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United States
Department of Agriculture
YEARBOOK of
AGRICULTURE
1937
75m Congress, 1st Session
House Document No. 28
UNITED STATES
GOVERNMENT PRINTING OFFICE
WASHINGTON : 1937
YEARBOOK
OF AGRICULTURE
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UNITE!) STATKS DEPARTMENT OF AGRICULTURE
Organization
of the United States Department of Agriculture
Secretary of Agriculture Henry A. Wallace.
Under Secretary M. L. Wilson.
Assistant Secretary Harry L. Brown.
Director of Extension Work C. W. Warburton.
Director of Finance W. A. Jump,
Director of Information M. S. Eisenhower.
Director of Personnel W.W. Stockberger.
Director of Research James T. Jardine.
Solicitor Mastin G. White.
Agricultural Adjustment Administration ; . . . H. R. Tolley, Administrator.
Bureau of Agricultural Economics A. G. Black, Chief.
Bureau of Agricultural Engineering S. H. McCrory, Chief.
Bureau of Animal Industry John R. Mohler, Chief.
Bureau of Biological Survey Ira N. Gabrielson, Chief.
Bureau of Chemistry and Soils Henry G. Knight, Chief.
Commodity Exchange Administration J. W. T. Duvel, Chief.
Bureau of Dairy Industry O.E. Reed, Chief.
Bureau of Entomology and Plant Quarantine Lee A. Strong, Chief.
Office of Experiment Stations James T. Jardine, Chief.
Farm Security Administration W. W. Alexander, Administrator.
Food and Drug Administration Walter G. Campbell, Chief.
Forest Service Ferdinand A. Silcox, Chief.
Bureau of Home Economics Louise Stanley, Chief.
Library Claribel R. Barnett, Librarian.
Bureau of Plant Industry Frederick D. Richey, Chief.
Bureau of Public Roads Thomas H. MacDonald, Chief.
Soil Conservation Service H. H. Bennett, Chief.
Weather Bureau Willis R. Gregg, Chief.
For sale by the Superintendent of Documents, Washington, D. C* Price $2.00 (vellum)
Contents
Page
The Secretary's Report to the President ; 1
Better Plants and Animals - II
What the Book Is About 119
GOVE HAMBIDGE
Vegetable Crop Breeding and Improvement — An Introduction . 171
VICTOR R. BOSWELL
Improvement and Genetics of Tomatoes, Peppers, and Eggplant . 176
VICTOR R. BOSWELL
Breeding and Improvement of Cucurbits 207
T. W. WHITAKER AND I. C. JAGGER
Onion Improvement 233
H. A. JONES
Breeding and Improvement of Peas and Beans 251
B. L. WADE
Improvement in the Leafy Cruciferous Vegetables 283
ROY MAGRUDER
Improving the Root Vegetables 300
C. F. POOLE
Improvement of the Salad Crops 326
ROSS C.THOMPSON
Improvement of Vegetable Crops — Appendix 340
VICTOR R. BOSWELL
Improvement of Sweet Corn * 379
C. F. POOLE
Popcorn Breeding 395
ARTHUR M. BRUNSON
Breeding and Genetics in Potato Improvement 405
F. J. STEVENSON AND C. F. CLARK
Strawberry Improvement 445
GEORGE M. DARROW
Page
Blackberry and Raspberry Improvement ........ 496
GEORGE M. DARROW
Improvement of Currants and Gooseberries 534
GEORGE M. DARROW
Some Unusual Opportunities in Plant Breeding 545
GEORGE M. DARROW AND GUY E. YERKES
Improving the Wild Blueberry 559
FREDERICK V. COVILLE
Progress in Apple Improvement 575
J. R. MAGNESS
Progress in Pear Improvement 615
J. R. MAGNESS
Grape Development and Improvement 631
ELMER SNYDER
Improvement of Stone Fruits 665
F. P. CULLINAN
Improvement of Subtropical Fruit Crops: Citrus 749
HAMILTON P. TRAUR AND T. RALPH ROBINSON
Nut Breeding 827
H. L. CRANE, C. A. REED, AND M. N. WOOD
Improvement of Flowers by Breeding 890
S. L. EMSWELLER, PHILIP BRIERLEY, D. V. LUMSDEN
AND F. L. MULFORD
Breeding Miscellaneous Forage and Cover Crop Legumes . . . 999
ROLAND McKEE AND A. J. PIETERS
Breeding Miscellaneous Grasses 1032
H. N. VINALL AND M. A. HEIN
Improvement of Timothy 1103
MORGAN W. EVANS
Alfalfa Improvement 1122
H. M. TYSDAL AND H. L. WESTOVER
Improvement in Soybeans 1154
W. J. MORSE AND J. L. CARTTER
Clover Improvement 1190
A. J. PIETERS AND E. A. HOLLOWELL
Varietal Improvement in Hops 1215
D. c. SMITH
Page
Improvement of Forest Trees 1242
ERNST J. SCHREINER
Breeding Problems With Angora Goats 1280
W. V. LAMBERT
Improvement of Milk Goats 1294
V. L. SIMMONS AND W. V. LAMBERT
Heredity in the Dog 1315
W. M. DAWSON
The Breeding of Turkeys 1350
STANLEY J. MARSDEN AND CHARLES W. KNOX
Duck Breeding 1367
A. R. LEE
The Breeding of Fur Animals 1379
FRANK G. ASHBROOK
Bee Breeding 1396
W. J. NOLAN
Fundamentals of Heredity for Breeders 1419
E. N. BRESSMAN
Vegetative Reproduction 1450
J. R. MAGNESS
A Chronology of Genetics 1457
ROBERT COOK
Index 1479
LIMITATIONS of space made it necessary to omit from this volume some of the material
prepared as a result of the survey of plant and animal improvement. Two complete arti-
cles were omitted — one on the Improvement of Subtropical Fruits Other than Citrus, by
Hamilton P. Traub and T. Ralph Robinson and one on the chromosomal basis of heredity
(Studies in the Behavior of Chromosomes) by A. F. Blakeslee, consulting member of the
Secretary,s Committee on Genetics. Both of these articles, however, will be published in
the 1937 Yearbook Separates, obtainable from the Superintendent of Documents, Wash-
ington, D. C, at a nominal cost. In order to keep the record complete and unified, the
summaries of the articles have been retained in the introductory chapter beginning on page
119. The remaining omitted material consists of the bibliographies on flower breeding and
on forest-tree breeding, which include a large number of references, and which will also be
published with the text of the articles in the Yearbook Separates; and a few pages of miscel-
laneous agricultural statistics. The latter are included in substance in the volume entitled
Agricultural Statistics, 1937, obtainable from the Superintendent of Documents. A notice
of the fact that Agricultural Statistics would hereafter be published as a separate volume
appeared in the foreword to the 1936 Yearbook.
riioto of Mendel-* suden by G. II. Bhull
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CREGOR MENDEL, the Austrian monk who bred fMH in the small monastery garden
at Uriinn, Austria (now Brno, Czechoslovakia), and a jMgp of the manuscript in which he
announced, in 1868, the fundamental lairs of heredity he hatl discovered. Mendel's researches
attracted no attention until the rediscovery of his trnrk in 19(H). Then Mendelism became
the foundation for mmlern plant and animal breeding.
THE YEAR
IN AGRICULTURE
REPORT OF THE SECRETARY OF AGRICUL-
TURE TO THE PRESIDENT OF THE UNITED
STATES, WASHINGTON, NOVEMBER 10, 1936
PROGRESS OF FARM RECOVERY
J? OUR years ago American agriculture was in the depths of de-
pression. Though farm commodity prices had dropped to nearly
50 percent below the pre-war average, the prices of the goods and
services that farmers usually buy were at or above the pre-war level.
This disparity was a cause of widespread agricultural ruin. Farm
bankruptcies were at record heights, dispossessed farmers joined the
urban unemployed, and farmers still struggling could not make ends
meet. There was a tremendous surplus of farm products; yet con-
sumers were suffering scarcity. Falling farm prices did not help
them much, because their incomes were falling too as a result of
declining trade and employment. The whole economic system was
out of balance.
Since then conditions have changed for the better. The improve-
ment has come about in the manner envisioned in 1933 — through
agricultural-price recovery with resulting increased demand for city
goods. Net farm income this year will be three times that in 1933.
All groups of farmers and all agricultural regions have participated
in the recovery, though not to the same degree. There is still distress
in some regions, as a result of drought in 1934 and again this year.
On the whole, however, agriculture is out of the red and making
progress toward financial rehabilitation.
This improvement has not been accomplished at the expense of other
economic groups. On the contrary, it has promoted their welfare.
Consumer buying power has risen with farm incomes, and the average
employed wage earner can buy more food today than he could at the
peak of urban prosperity in 1929. Food prices are still 15 to 20 per-
cent below the predepression level. In spite of two great droughts in
3 years the total food supply for the current marketing season will be
within 1 or 2 percent of what it was in 1935-36. Meat production is
below normal requirements; but the output of some other products
has increased, and exports are relatively low. Hence the national
average per-capita consumption of foods has shown little change.
Industrial production is 80 percent above the low point of 1932. In
short, the economic system has moved toward balance, with larger
incomes in both town and country, and with profits replacing deficits
in both farm and city balance sheets.
2 YEARBOOK, 1937
Farm recovery began in 1933 promptly after the adoption of a
national farm-readjustment program, accompanied by revaluation of
the dollar. As the farm income rose, farmers started clearing off their
debts and taxes. They recommenced buying industrial goods. Re-
covery went on at a faster pace in 1934, 1935, and 1936, despite the
handicap of drought. Between 1932 and the end of 1934 shipments
of industrial goods to agricultural areas increased nearly 43 percent,
and shipment of goods used in farm production increased 75 percent.
New-car registrations in agricultural States in the first half of 1935
were 147 percent larger than in the first half of 1933. Farmers were
not monopolizing the benefits of farm recovery but were diffusing it
throughout the country and putting life blood into business. What
nonf armers had contributed in processing taxes and benefit payments
they got back with interest. Reciprocally the revival of urban trade
benefited agriculture, and the whole economic picture brightened.
The Production-Control Programs
In the early stages of the farm recovery, the production of farm
commodities had to be restricted so as to reduce the surpluses that
were not moving into foreign markets. When drought in 1934 and
again this year reduced production too drastically, some people
questioned the logic of crop adjustment. Scarcity, however, was
never intended and never approached. This country's farm produc-
tivity is so tremendous that recovery from drought comes quickly.
Full use of the available acreage normally means surpluses. Agri-
culture produced as usual in the first years of the depression, while
urban industry reduced its output by nearly 50 percent.
In bringing their production more nearly in line with demand,
farmers were simply copying the behavior of other groups when
faced with overproduction and declining markets; with the import-
ant difference, however, that only export surpluses came within the
farm-reduction program. As soon as the demand improved, farm-
ers increased their acreage and livestock breeding. Though drought
in 1934 and 1936 kept the production from rising proportionately,
it will rise eventually. Both the farmers and the present National
Government aim at adequate production for domestic requirements,
plus whatever additional supply can be sold profitably abroad.
Undoubtedly, most Americans want to maintain our agriculture on
a proprietary, landowning, family basis. Certainly this Adminis-
tration does. It is not desirable to have either a peasant agriculture
manned by tenants and laborers, or a collective agriculture run by
the central Government. This idea involves certain responsibilities.
Farmers must be permitted to earn a profit, a margin of income
oyer expenditures ; otherwise the family farm becomes bankrupt, and
either tenancy or Government farming supervenes.
But if agriculture is to be profitable, it must have prices sufficient
on an average and in the long run to exceed its fixed charges and
expenses of production ; and this is impossible when supplies greatly
exceed the effective demand. Those who object to the rational ad-
justment of the farm output to the farm demand practically take
the position that farmers should produce, without regard for the
reward obtainable, as long as anyone needs their crops. Needless to
THE YEAR IN AGRICULTURE 3
say, production on that basis cannot continue in any business. Profit-
able farming, in short, means farming adjusted to the available
market. If want continues after that has been accomplished, the
remedy is to create more buying power, rather than to compel farmers
to produce indefinitely at a loss.
Comparison With Industrial Production
Farmers cannot be charged with having promoted scarcity when
they readjusted their production for export more nearly in line with
the available market. Index numbers of production and prices have
been computed in this Department, with the 5 years 1925 to 1929
taken as 100. Farm production was 100 in 1930 and 106 in 1931, from
which point it declined moderately to 90 in 1934 and 1935. Indus-
trial production fell year by year after 1929 until it reached a low
point of 56 in 1932. Thereafter it recovered gradually until in 1935
the index stood at 82, as compared with the farm production index
of 90. It should be borne in mind that the industrial index includes
the output of food manufacturers, an item which, of course, reflects
farm production. Were this item excluded from the industrial index,
the contrast between farm and factory production would be still
more striking. Farm production remained high and farm prices
relatively low until farm adjustment got under way. Industrial pro-
duction and prices showed the reverse relationship.
Moreover, the farm situation in 1933 was such that reduced produc-
tion would have come about eventually in any case, with or without
Federal assistance. That is the typical end-product of low prices.
Usually, reduced production results from drastic competition and
the elimination of the weaker producers. Concerted action after
1933 enabled the vast majority to survive. But this procedure did
not reduce production more than it would have been reduced eventu-
ally by the other process, and it prevented deterioration of the
agricultural plant through farm abandonment.
Looking back over the last 4 years, we can see that despite the
droughts we have advanced toward balanced abundance. Four years
ago our factories were producing below and our farms above con-
sumer requirements, with both branches of production losing heavily.
Today we have a forward movement in both town and country. Farm
recovery has reanimated urban life without hurting any group. The
disparity between urban and rural production has been substantially
removed; likewise the disparity between farm and nonfarm prices.
That the results have been beneficial everyone can testify from
his own experience. Our higher national income, our increased
employment, and the increase that has taken place in the money
value of both agricultural and industrial assets show that recovery
has been general.
FARM INCOME AND BUYING POWER
This Department makes available two series of farm-income statis-
tics. One series records current receipts from sales plus A. A. A.
payments, and the other shows the estimated gross income from the
production. Farmers' receipts from sales plus A. A. A. payments in
1936 will probably reach $7,850,000,000, or about 11 percent more than
4
YEARBOOK, 1937
the corresponding receipts in 1935. This figure is 81 percent more
than the cash farm income of 1932 and only 25 percent less than that
of 1929. Table 1 shows the decline that took place from 1929 to 1932
and the subsequent steady recovery :
Table I. — Changes in income from 1929 to 1936-37
Calendar year
Cash income
from market-
ings
Crop year
Gross income1
1929
$10, 479, 000, 000
8,451,000,000
5,899,000,000
4, 328, 000, 000
5,117,000,000
6,387,000,000
7, 090, 000, 000
7,850,000,000
1929-30
1930-31
1931-32
1932-33
1933-34
1934-35
1935-36
1936-37
$11, 941, 000, 000
9,454,000,000
6, 968, 000, 000
5, 337, 000, 000
6,406,000,000
7, 276, 000, 000
8, 508, 000, 000
9, 200, 000. 000
1930
1931
1932
1933
1934
1935
1936«
includes cash returns from calendar-year marketings of livestock, and from crop-year marketings of
crops plus the farm value of production retained for use in the farm home. A. A. A benefit payments in-
cluded in gross-income estimates as well as in the annual cash income service.
> Preliminary.
It will not be possible to indicate in detail the gross income from
the farm production in 1936 until well along in 1937, when the
marketings will be more nearly completed. It probably will approach
$9,200,000,000, as compared with $8,508,000,000 from the production
of 1935. It represents a total advance of about $3,900,000,000 or
72 percent, from the low point of 1932, but it is about $3,000,000,000,
or 23 percent, below the figure for 1929. Gross income in that year
was 17 percent higher than in 1934-35 and 59 percent higher than in
1932-33. It was 71 percent of the 1929-30 total.
Net income remaining to farmers increased after 1933 proportion-
ately more than the gross income because farm-commodity prices rose
more than production expenses and other charges. After paying
current production expenses, allowing for the depreciation of build-
ings and equipment and deducting rent, interest, taxes, and the wages
of hired labor, the income available to farm operators for their labor,
capital, and management from the production of 1935 was $4,538,-
000,000. This may be compared with $3,467,000,000 in 1934 and
$1,492,000,000 in 1932. Whereas the increase in the gross income
from 1934 to 1935 was only 17 percent, the increase in the income
available to farm operators was 31 percent. It will be noticed that
it was more than three times as large as in 1932. Moreover, much
of the expenditures for production items in 1935 went for machinery,
buildings, and repairs, which are in the nature of permanent im-
provements. Farmers' expenditures for capital items m 1935 approx-
imately equaled the estimated depreciation of their buildings and
equipment, for the first time since 1930.
Exchange Value of Farm Products
Another index of the farm position is the ratio between prices re-
ceived and prices paid by farmers. Farm commodity prices have
risen more since 1933 than the prices of nonfarm goods and services.
Previously the trend had been in the opposite direction. In March
THE YEAR IN AGRICULTURE 5
1933, with agricultural prices only 55 percent of the pre-war average,
nonagricultural prices were still at 100 percent of the pre-war level.
Farm products in 1935 averaged 108 percent of pre-war prices, while
nonagricultural prices had risen to 125 percent. Farm prices had
gained on nonfarm prices, but had not attained pre-war parity. This
ratio indicates the exchange value of farm commodities or their unit
purchasing power. The index of farm-commodity purchasing power
was 55 percent of pre-war in March 1933, 73 percent for the year 1934,
and 86 percent for the year 1935. By August 1936 it had climbed to
98 percent.
The purchasing power of farm commodities is not identical with
the purchasing power of the farmer. It indicates what a given
quantity of farm products will buy, but not what the total volume
will command. A closer estimate or the farmer's purchasing power
can be derived from the ratio between the cash farm income and the
prices that farmers have to pay for goods and services. With prices
paid by farmers in 1936 equal to 80 percent of what they paid in 1929,
the 1936 cash income of $7,850,000,000 is equivalent to $9,800,000,000
in terms of 1929 nonfarm prices. Otherwise stated, the purchasing
power of the cash farm' income in 1936 will be only 7 percent less
than that of 1929. As compared with the purchasing power of the
cash farm income in 1932 it represents an increase of 60 percent.
Moreover, agricultural debt charges, taxes, and wage costs were lower
in 1936. Allowance made for this additional factor would give an
agricultural purchasing power still closer to that of 1929.
Certain aspects of the distribution of the farm income should be
noticed. Cash income from meat animals in 1935 exceeded the corre-
sponding figure for 1932 by 73 percent, and in the first 7 months
of 1936 it advanced 27 percent over the total for the corresponding
period of 1935. From dairy products in 1935 the cash income was
30 percent more than in 1932 ; the income from poultry and eggs was
45 percent more. These industries made small additional gains in the
first 7 months of 1936. From grains the cash income in 1935 was 61
percent more than in 1932 and from cotton 46 percent more. Fruits
and vegetables recorded a 41-percent gain. Income from marketings
of all crops was 36 percent greater in the first 7 months of 1936 than in
the corresponding period of 1935. These percentages do not include
the A. A. A. payments.
With marketings and benefit payments included, the total cash
income from grains in 1935 was 133 percent larger than in 1932.
From cotton it was 77 percent larger. In the first 7 months of
1936 the total cash income from marketings with A. A. A. payments
included was 17 percent more than in the corresponding period of
1935 though the A. A. A. payments were considerably smaller.
Regional Percentages Vary
Regional percentages of gain in 1935 over 1932 range from 33
percent in the North Atlantic States to 81 percent in the South
Atlantic States. Mainly the regional differences reflect the different
price behavior of various commodities, but the aftermath of the
1934 drought was a factor also. Proportionately less gain for the
dairy regions than for other regions was a natural consequence of the
6 YEARBOOK, 1937
fact that the dairy regions had suffered less in the early years of the
depression.; but for the opposite reason the grain-growing areas show
a relatively large increase, though reduced marketings have tended to
offset the price gains.
Each of the principal agricultural regions, except the South Cen-
tral States, showed an increase in income in the first 7 months of
1936, as compared with the corresponding period in 1935. In the
South Central States, where smaller Government payments offset an
increased return from marketings, the income was approximately
the same. The gains in the other regions ranged from 14 percent
in the North Atlantic, South Atlantic, and Western States to 23
percent in the West North Central States.
Accurately to measure the respective influences of the factors re-
sponsible for the recovery in farm incomes is difficult if not impos-
sible. Mainly the improvement reflects price gains, supported by
increased consumer buying power. Factors in the price gain include
the revaluation of the dollar, the A. A. A. adjustment programs, the
reduced production caused by the 1934 drought, and the liquidation
of surpluses. In 1936 increased marketings were a factor in the
income gain. Farm prices in the first 7 months of the year averaged
slightly lower than in the corresponding months of 1935. In the
later months, however, farm prices advanced as a result of the
drought, and for the full year the farm-price average will probably
exceed that of 1935.
In estimating the prospects for the longer future the most basic
factor is the level of consumer incomes. Broadly, the income of agri-
culture varies more closely with the national income than with the
level of farm prices. It is encouraging to note that the money income
of the nonfarm population in August 1936 averaged 13 percent more
than in August 1935 and 32 percent more than in the corresponding
Eeriod of 1933. With their improved income, consumers were able to
uy 7 percent more food and 12 percent more of the other items in
their budget than in the previous year, but 6 and 11 percent, respec-
tively, less of these items than in 1929. Earnings per employed worker
have more than kept pace with food prices. Needless to say, farmers
as a result of their income gains can deal more effectively with
the consequences of the 1936 drought than they could with those
of the drought of 1934.
Farm Prices and the Consumer
Effects of the drought on the cost of living will probably be similar
to those produced by the drought of 1934. From crop data available
in September it was estimated that for the 1936-37 season food sup-
plies m general will be about 3 percent below the 1935-36 level, about
1 percent below the level of 1934-35, and about 5 percent below the
1925-29 average. Certain vegetables, particularly potatoes, will be in
short supply. The output of fruits and vegetables and of dairy prod-
ucts will be lower, and after the turn of the year the supply of meats
will be reduced. This will result in higher meat prices to some
extent offset by seasonal declines in other food prices. In the com-
parable situation after the 1934 drought, retail food prices as a whole
in the first half of 1935 averaged about 11 percent higher than they
THE YEAR IN AGRICULTURE 7
did during the first half of 1934. Food constitutes only about one-
third of total living costs, hence an increase of, say, 10 percent in the
cost of food tends to produce a rise in total living costs of only about
3 percent.
Analysis of the trend in nonfarm income indicates that consumers'
incomes in the first half of 1937 will increase at least as much as the
cost of living. In other words, the purchasing power of consumers
generally, in terms of goods and services, will not decline. Had there
been no drought, it would have increased ; and the foregoing remarks
do not signify that consumers can regard with indifference the great
change produced by the drought in the supply situation. But the
main effect will be temporarily to arrest a gam rather than to cause
a drop in the real income of consumers. Wage earners actually
employed could buy with their wages more of the necessities of life
in the summer of 1936 than they could in 1929 because retail prices
were lower on the average. In terms of foods the purchasing power
of employed workers actually advanced after 1929, when farm prices
began falling. It remained above the 1929 level and reached a new
high point in 1936.
In total purchasing power the position of city workers deteriorated
during the first years of the depression. Pay rolls declined, while
many nonfood items in the family budget remained unchanged. In
1934, 1935, and 1936, however-, nonfarm labor incomes increased.
These incomes for the first half of 1936 aggregated $23,492,000,000,
as compared with $19,617,000,000 in the first half of 1933. More men
were engaged in manufacturing in the summer of 1936 than at any
previous time in the last 5 years ; in July industrial production was
108 percent of the 1923-25 average, the highest point reached since
November 1929. .According to the seasonally adjusted index of the
Federal Eeserve Board, the July industrial production was 83 percent
above the low point to which it fell in March 1933. The relatively
small rise in the cost of living which will be the inevitable consequence
of the drought will be substantially offset by recovery in urban
buying power.
OUR NATIONAL AGRICULTURAL POLICY
It is commonly believed that the United States never had a truly
national agricultural policy until after the World War; but the coun-
try has always had a national agricultural policy. In the period of
westward migration, of rapid land settlement, and of ruthless ex-
ploitation of natural resources, the policy was negative. It was
mainly one of noninterference with the private appropriation of land
for use or misuse. Despite its laissez-faire character, we cannot call
that procedure a mere lack of policy. It expressed a definite philoso-
phy and, indeed, a definite program. It was what the dominant
forces in the country wanted and what the majority of the people at
least tacitly accepted. Our national agricultural policy in the nine-
teenth century reflected the belief that national welfare could best be
promoted through individualism and unrestricted competition.
For a long time this theory apparently stood the test of practice.
With abundant land, an open frontier, and a relatively sparse popula-
tion, the quickest way to increase production, and therefore wealth,
8 YEARBOOK, 1937
was to get the resources into private hands. Occasionally production
overshot the market; but the resulting depression did not last long
and did not shake the country's faith in the exploitation program.
Various administrations encouraged farming, ranching, lumbering,
and other land uses through homestead laws, grazing privileges, land
grants, favors to transportation companies, lenient taxation, and irri-
gation. Few looked forward to the closing of the frontier and to the
ruthless competition that would ensue. Most people seemed to think
the policy that had been adopted could be continued indefinitely.
As a matter of fact, as most people now perceive, the exploitation
policy created problems that today necessitate a conservation policy.
Recklessness in one age inevitably imposes prudence on the next.
There are sharp contrasts between the agricultural views and pro-
grams that dominated the nineteenth century and those that shape
our agricultural policy today. But the contrast does not mean that
the present has broken with the past or that tradition has been sharply
wrenched from its natural path. On the contrary, it signifies that
cause and effect have operated normally. The new agricultural policy
is the direct result of the old one and of the conditions and problems
which the old policy created. As the occupation of the continent pro-
ceeded, the expansion program ran out of material. It ran out of
land and forced the land hungry into submarginal farming, destruc-
tive grazing practices, and forest devastation. Land charges accumu-
lated on the older-settled land and drove producers into overproduc-
tion. Exploitation, in short, created the need for conservation, and
simultaneously excessive competition generated a need for corrective
regulation. It is because our forbears went too far in one direction
that we must now move in another.
No Break With Evolutionary Trend
In the transition from the old to the new agricultural philosophy
there is no sudden break with the evolutionary trend, and no capricious
improvisation of new doctrine. On the contrary, the link between the
old exploitation and the new conservation, and between the old unreg-
ulated competition and the new principle of cooperative adjustment,
is direct and close. Perhaps the authors of the exploitation program,
were they here today, would disown their offspring ; but the parentage
can be demonstrated. After the spendthrift has wasted his money he
must begin to save; after a country has squandered its natural re-
sources it must learn to husband what remains. Our national agri-
cultural policy since the World War has been criticized as confused
and uncoordinated, but study of it will reveal a logical and indeed
predestined course.
Thus the Federal Farm Board came into existence to handle sur-
pluses left by wartime and post-war expansion. The McXary-Haugen
plan, though twice vetoed, stamped its mark on subsequent legislation
as a first approach to the problem of the export surplus. The A. A. A.
programs were an emergency effort to substitute concerted for hap-
hazard crop adjustments in a catastrophically falling market and to
bring agriculture abreast of urban industry in the regulation of pro-
duction. The new Soil Conservation and Domestic Allotment Act,
though weaker in crop-adjustment power than the measure it replaced,
THE YEAR IN AGRICULTURE 9
had the great merit of launching a positive attack on the dual prob-
lem of soil destruction and unbalanced cropping. In varying degrees
all these approaches to the agricultural problem betokened a national
recognition of the fact that modern problems cannot be solved by
ancient formulas, and that agricultural policy today is necessarily in
large measure the opposite of what it was in the period of the open
frontier.
Agricultural policy draws its inspiration, not from the accidents
of politics but from fundamental economic changes. In the shaping
of American agricultural policy we can distinguish two great con-
trolling forces, each of recent origin. First, of course, is the dis-
appearance of the open frontier and the resulting pressure of popu-
lation on the resources available with its threat of soil wastage and
soil destruction. Second is the world-wide growth of economic regu-
lation, not only in trade but in production. Governments are assum-
ing greater and greater responsibilities for the regulation of com-
merce both domestic and foreign, and industry is becoming cartelized
throughout the world. Into an economic system of that kind, a
purely competitive, wholly unregulated agriculture will no longer fit.
These two great forces seem destined to exert an increasing influence
which will express itself in legislation and policy no matter what
political party may be in power. Modern agricultural policy in the
United States is not the arbitrary invention of an economic group
with a special interest to promote but is a national response to
an altered economic world. It is not merely an attempt to deal
with temporary evils but a profound readjustment to permanently
changed conditions.
Landmarks in Agricultural Policy
It is interesting to recall the contribution of the past to present
agricultural policy. In 1862 Congress passed the Morrell Act, pro-
viding Federal grants of land to the States for the establishment of
colleges in agriculture and the mechanic arts. After half a century
of progress in agricultural technology, agriculture began to demand,
economic guidance. Accordingly, this Department developed exten-
sive and varied economic services in which research was combined
with the regular gathering of crop and market data, and with nu-
merous related services such as commodity grading and standardiza-
tion, and shipping- and receiving-point inspection. In 1921 these
and other activities were concentrated in the Bureau of Agricultural
Economics. In 1922 Congress passed the Capper-Volstead Act, giv-
ing legal recognition to the right of farmers to organize cooperative
associations for the marketing of their products. In 1927 and again
in 1928 Congress passed the McNary-Haugen legislation, though each
time the legislation encountered a Presidential veto. Then came the
Agricultural Marketing Act of 1929 and the creation of the Federal
Farm Board. In 1933 the Agricultural Adjustment Act: with its
provisions for processing taxes and cooperative crop adjustments,
went into effect and remained in effect until the United States Su-
preme Court invalidated it in January last, through decisions in the
Hoosac Mills and rice millers' cases. Throughout the entire period
covered by this brief review American farmers manifested an in-
138904''— 3T 2
10 YEARBOOK, 1937
creasing tendency to effect organization and also to look to the
Federal Government for aid in solving their economic problems.
Because of the adjustments made under the Agricultural Adjust-
ment Act during the last 3 years and because the drought helped to
liquidate certain of the surpluses, the present program under the Soil
Conservation and Domestic Allotment Act is well fitted to present
needs. Farmers recognize that, while this agricultural conservation
program will be of immediate help in stabilizing supplies through
the encouragement of more extensive uses of land, the program itself
is not a direct production-control measure. A return to normal
weather conditions would revive the problem of agricultural sur-
pluses. I am inclined to believe that farmers understand what con-
fronts them in the future and that they will look forward to making
use of the method of meeting the problem of surpluses which the
Supreme Court left open to them. The Soil Conservation and
Domestic Allotment Act contains a provision which will facilitate
this step in 1938 should farmers decide to meet their supply problem
through cooperation of the States. This provision is, of course, the
direct descendant of the invalidated Agricultural Adjustment Act,
and preserves some of the ideas contained in that measure, as well
as some of the principles developed in the application of the A. A. A.
programs. It would be well, therefore, before examining methods
and results under the new law, to glance back at the legacy bequeathed
by the A. A. A.
Agricultural Adjustment Act Effective
It is evident, from the improvement that took place in the position
of agriculture between 1932 and 1935, that the Agricultural Adjust-
ment Act forwarded its main purpose. This was to eliminate the
crushing surpluses that had piled up previously and to raise farm
incomes immediately through various measures calculated to support
prices. From 1932 to 1935, the period during which A. A. A. pro-
grams were in effect for cotton, wheat, tobacco, corn, and hogs, the
combined farm cash income from these commodities increased 90
percent. Cash income from these five major commodities increased
from $1,365,000,000 in 1932 to $2,593,000,000 in 1935. From all other
farm products the cash income increased from $3,012,000,000 in 1932
to $4,307,000,000 in 1935. In 1932 the largest farm population in
the Nation's history had the smallest farm cash income reported in
the 26 years for which records are available. The turning point came
with the adoption of the Agricultural Adjustment Act, though this
measure was only one of the factors responsible for the agricultural
improvement. Dollar revaluation, business recovery, credit relief ex-
tended through the Federal Farm Credit Administration, and other
influences contributed. All these influences combined gave farmers
in 1935 a cash income available for living larger than in any year
since 1929. They had to pay somewhat more for goods and services
in 1935 than they did in 1932, but with allowance made for that, the
purchasing power of the farm cash income in 1935 was still 35 percent
larger than it had been in 1932.
The great drought of 1934, which cut our production of feedstuffs
in half, necessitated modifications in the A. A. A. program so as to
THE YEAR IN AGRICULTURE 11
encourage production of emergency feed crops that year and to pro-
vide for certain increases in production the next. It became ad-
visable also to work toward a better coordination of the various
commodity programs and to provide for greater regional and area
differences so as to promote good farm management and good land
use. Certain shortcomings had developed in the emergency applica-
tion of the programs, notably a tendency to fix or freeze production
in the historic mold, without proper regard for the changing re-
quirements of different areas. But the crop-adjustment programs
had shown themselves to be useful in promoting soil conservation
and good farming. They fostered some shift from soil-depleting
cash crops, such as cotton and wheat and corn, to soil-building crops
such as grasses and legumes.
To strengthen and develop this favorable tendency, the A. A. A.,
working with the State experiment stations and with other branches
of this Department, launched studies in regional planning and modi-
fied its crop-adjustment contracts with farmers. It began to place
less emphasis on flat percentage changes in production and more on
differential adjustments to the requirements of local as well as of
national conditions. In this way the A. A. A. developed principles
which found continued application when the invalidation of process-
ing tax and production control provisions of the Agricultural Ad-
justment Act led Congress to pass the Soil Conservation and Do-
mestic Allotment Act. Under the A. A. A. the primary objective
was production control, with soil conservation a secondary though
increasingly important object. Under the new law soil conservation
becomes the primary aim, with some crop adjustments coming as a
byproduct. Probably in a period of good crops and high yields the
degree of crop control attainable under the new measure will not be
adequate, but for the time being it works for a better crop balance.
The emphasis it puts on grass and legumes has the double advantage
of making our agricultural system less intensive, while at the same
time conserving soil wealth.
Methods Under New Law
Under the Soil Conservation and Domestic Allotment Act the
Federal Government in 1936 made grants to farmers cooperating in
soil-conserving and soil-building programs. It did not make use of
contracts. Cooperating farmers simply planned their operations in
line with definite soil-conservation standards, worked out with pro-
ducers, soil specialists, and State agricultural leaders. They obtained
their grants after officials had checked the performance with the
standards. For this purpose Congress made $470,000,000 available
for the year, the goal for which was to have 130,000,000 acres in
soil-conserving crops as compared with 100,000,000 acres in 1930.
Though the program for the year was national in scope, the country
was divided for administrative purposes into five regions — the north-
eastern, the east central, the southern, the western, and the north
central — and the practices for which payments were made and con-
ditions which had to be met were varied so as to meet the particular
needs of the farmers in each region.
12 YEARBOOK, 1937
After January 1, 1938, the program will enter upon a State-aid
phase; in other words, the Federal Government thereafter will make
soil-conservation grants, not directly to individual farmers, but to
the States for distribution to cooperating farmers. The Soil Con-
servation and Domestic Allotment Act sets up five objectives:
Preservation of soil fertility, diminution of soil exploitation, promo-
tion of the economic use of land, the protection of rivers and harbors
against the results of soil erosion, and the attainment of parity income
for agriculture. Power to promote the last-named object will not
be available until the State-aid phase of the act goes into effect, but
economists and farm-management specialists are already studying
the means by which it may be used, provided it is needed.
Soil conservation and good farm management were important
objectives under the A. A. A. programs. As experience showed the
need, the A. A. A. modified its original requirements so as to give
contracting farmers more scope in combining their various crop enter-
prises in harmony with the national crop-adjustment programs and
more incentive to protect and restore soil values. In the north-
central region, for example, from two-thirds to three-fourths of the
acreage diverted from corn, wheat, cotton, and tobacco went into
legumes and grasses. This diversion, though of a temporary nature,
was a good beginning in cooperative soil conservation. It was the
first large-scale effort to correct the bad effects of cropping practices
developed in the wartime and post-war booms, when much land not
suited to continuous intensive cultivation was brought under the
plow. In the South, farmers were allowed to increase their acreage
and production of food and feed crops, which meant an increase in
the farm standard of living.
The necessity for soil-conserving practices was long overdue. Soil
depletion had characterized American agriculture for decades, and
the overcropping which took place during and after the World War
made matters worse. Though the demand for farm products declined
in the twenties, and though farmers had apparently a strong motive
to alter their cropping systems, the acreage of cultivated, soil-deplet-
ing crops continued to increase. Burdened with debt and driven by
low prices to seek compensation through more and more production,
farmers kept on mining the soil. The A. A. A. enabled them to
adopt a better course. With higher prices and benefit payments in
view, they could begin to think of their permanent, as well as of their
immediate, interest in the land and, to some extent, could stop selling
the fertility of the soil piecemeal with the crops at low prices to
foreign countries.
Research and Demonstration Authorized
The soil problem received special recognition when Congress passed
the Soil Conservation Act of 1935, which provided for a general
program of research and demonstration to be conducted by the Soil
Conservation Service in cooperation with the State experiment sta-
tions and with farmers. Broadened and amended after the Hoosac
Mills decision, the measure evolved into the Soil Conservation and
Domestic Allotment Act. This act recognizes a social as well as an
individual interest in soil conservation and provides the individual
THE YEAR IN AGRICULTURE 13
farmer with means to advance both interests simultaneously. It
facilitates a concerted effort to correct the grave mistakes that have
been made in the past, and particularly since the World War, in the
use of farm land.
Much of the land that came under the plow for the first time
during and after the World War lies in the western Great Plains,
and cannot be expected in normal circumstances to give profitable
yields. Moreover, it is extremely subject to wind erosion. In the
older cultivated regions, especially in the Corn Belt and South, there
is heavy overcropping. In the Corn Belt, according to a report of
the National Eesources Board, overcropping is a major soils prob-
lem, particularly on the erosible land along the eastern edge of the
sand hills, the plains of southern Nebraska, and the hilly areas
of southern Iowa, northern Missouri, and western Illinois. Over-
cropping in this area is damaging more than 36,000,000 acres of
farm land. Besides exposing the land to erosion, it is making soil
harder to work, reducing the plant-food content and exposing land
to increased danger of drought. Erosion and the drastic depletion
of soil fertility due to overcropping are common throughout the
South, and erosion is far from unknown in New England, even
though much of the farm land is already in soil-conserving crops.
What is happening to farm lands throughout wide areas may be
indicated by the results of experiments on the historic Morrow plots
at the University of Illinois. One comparatively level plot which
had been continuously in corn and oats for 23 years lost 4 tons of
humus per acre, and yields steadily declined. On another plot, on
which corn, oats, and clover were rotated, and on which fertilizers
were applied, the soil retained 14 tons more of organic matter per
acre than did the soil of the corn-and-oats plot. Studies in Ohio
revealed that during the last 60 years the adoption of better varieties,
better seed, and scientific methods for the control of insects and
plant pests merely balanced the downward trend in the average
productivity of the soil. In other words, more than half a century
of applied science showed no net gain because it did not include
effective soil conservation. Comparable studies in Iowa demon-
strated that present farm practices will not maintain the fertility
of the soil and control erosion, and that in order to do so it will be
necessary to reduce the corn acreage considerably. On rolling land
the major problem is soil washing. Land cropped continuously in
corn, in soil tests at the University of Missouri, lost seven times as
much soil as land planted to a rotation of corn, wheat, and clover,
though the slope was only 4 percent. Land kept in bluegrass lost
only one-sixtieth as much soil as that kept in continuous corn.
Soil Depletion in the South
Because of the system of farming followed in the South, the soil
has been greatly depleted. Southern farmers devote a larger per-
centage of their cropland to soil-depleting crops than do farmers in
any other part of the country. In the nine States of the southern
region, with the exception of Florida, the ratio of soil-depleting
cropland to the total cropland ranges from 76 to 92 percent and
averages approximately 80 percent. The large percentage of clean-
14 YEARBOOK, 1937
tilled row crops is a heavy drain on soil resources. In acreage cot-
ton and corn are the principal crops, though there is a considerable
acreage of wheat in Oklahoma and Texas. Cotton and corn both
leave the land comparatively bare in the winter and subject to soil
erosion. The mild climate and the heavy rainfall aggravate the
problem.
In 1936 the nine States shifted about 13 million acres from soil-
depleting commercial crops to soil-conserving noncommercial crops.
This was more than 40 percent of the total acreage so diverted in
the United States. Soil conservation in the South calls for a rela-
tively large percentage of diversion. But the dense farm popula-
tion and, in recent years, the low price of cotton have made the
operation difficult. Eleven million people, or one-third of our farm
population, live in the nine States included in the southern region.
Prior to 1936 this situation was alleviated to some extent by the
agricultural adjustment programs, which embodied a number of
soil-conserving features ; and in 1934 and 1935 about 14 million acres
normally in cotton was shifted to the production of food and feed
crops, and to crops that conserve the soil. The acreage of soil-
conserving crops in the South in 1936 was the largest on record.
In setting up the soil-conservation program in the western region
it was necessary to take into consideration a great diversity of crops,
of types of farming, and of farming practices. This region comprises
Arizona, California, Colorado, Idaho, Kansas, Montana, New Mex-
ico, Nevada, North Dakota, Oregon, Utah, Washington, and Wyo-
ming. In the more humid areas the major problem is that of prevent-
ing erosion by water, while in the Great Plains erosion by wind de-
mands attention. The so-called dry-land area requires special safe-
guards. Irrigation farming has its peculiar problems. In parts of
Oregon, Washington, and northern Idaho summer fallowing enters
into the system of farming and calls for appropriate conservation
practices. In certain areas payments were made for contour cultiva-
tion, and particularly for contour listing, which tends to check
erosion by both wind and water. Where wind erosion is serious, strip
cropping and strip fallowing were encouraged. In three States pay-
ments were made for the use of lime or gypsum in soil building ; and
in States where noxious weeds are very prevalent, weed-control meas-
ures were regarded as a soil-building practice.
Organization for the Program
The organization set-up for carrying out this year's program re-
tained the principle of farmer cooperation, which had been developed
under the A. A. A. programs in 1934 and 1935. As a coordinating
body between the Federal Administration and local bodies there was
established for each State a State agricultural conservation commit-
tee. This consisted of from three to five members, appointed from
more or less distinct type-of-f arming areas. The State committees
generally exercised advisory and supervisory functions. They as-
sumed the responsibility for checking the work of the county com-
mittees in establishing bases for supervising the checking of perform-
ance by cooperating farmers and tor reviewing county expenditures
THE YEAR IN AGRICULTURE 15
and program disbursements. They were also responsible for the rela-
tive cost, operation, and the effectiveness of the programs.
Within the counties the organization was similar to that established
under the earlier A. A. A. programs. Each county had its county
and community committeemen, all of them farmers. These commit-
teemen were elected by their neighbors in each township or other simi-
larly defined area, to assist program participants in executing work
sheets and in planning their farming operations in line with conser-
vation standards. Also, the township committeemen helped, at the
end of the season, to check performance and to certify the claims of
cooperating farmers for Federal grants. Responsibility for super-
vising and coordinating the work of the various community com-
mitteemen, for reviewing program forms and documents, and for
making final recommendations for the adjustment of individual "soil-
depleting bases" within the prescribed limits for the county, rested
with the county committee, which accordingly had authority to in-
vestigate local problems. Educational work necessary in the ex-
planation and application of the programs was under the direction
of the State agricultural extension services, which also were given
large administrative duties in the West and South.
In determining an individual farmer's contribution to the national
soil-conservation goal and therefore establishing the amount of his
claim upon the grant funds available the starting point was the soil-
depleting base. Cropland uses were divided into two major classifi-
cations, soil-depleting and soil-conserving. Among the soil-deplet-
ing crops may be mentioned corn; small grains harvested for grain
or hay, or- seeded alone and pastured ; annual grasses pastured or
harvested for grain or hay; soybeans, cowpeas, and field beans if
harvested for grain; the sorghums, potatoes, commercial truck and
vegetable crops, sugar beets, tobacco, and cotton. In the soil-con-
serving category were included most of the legumes and perennial
grasses; soybeans, field beans, cowpeas or field peas, if these crops
were turned under as green manure ; small-grain crops if turned un-
der as green manure and followed by soil-conserving crops; orchards
and vineyards interplanted with winter cover crops; acreages sum-
mer-fallowed if followed with soil-conserving crops. The two cate-
gories include many crops not here mentioned. Those cited merely
illustrate the principle. After drought conditions developed in June
and July, the Administration authorized many changes and addi-
tions to the crop classifications so as to meet the unexpected weather
conditions.
For the farm owner or operator who planned to cooperate, the
county committees established a general soil-depleting base, and in the
South special bases were established for cotton, tobacco, and peanuts.
This base represented a normal acreage of the soil-depleting crops on
the farm, with the total acreage serving as the starting point. The
county limit was the ratio of the soil-depleting crop acreage to all
farm land or to all cropland in the county. As representing the most
normal period for the production of soil-depleting crops in recent
years, the north-central region took 1932 and 1933 as the base years for
establishing the county limits, the western and southern regions took
1928-32, and other regions adopted different base years. County
16 YEARBOOK, 1937
committees notified farmers of their preliminary bases, but these were
not necessarily final. Farmers had the right to appeal for recon-
sideration of their bases, first to the county committee and then to the
State committee. This appeal procedure, besides being consistent
with the democratic principle underlying the whole program, per-
mitted the correction of unintentional errors. By taking all possible
precautions to have the bases fairly established, the Administration
hoped that they would prove satisfactory not only for the current
year but for subsequent programs.
Two Classes of Payments
Farmers cooperating in the soil-conservation program could qualify
in 1936 for either or both of two classes of payments, the class 1 or
soil-conserving payment, and the class 2 or soil-building payments.
The class 1 payment was available to farmers who diverted a portion
of their soil-depleting base acreage to soil-conserving crops or uses.
Farmers were eligible to receive this payment on any number of acres
up to 15 percent of their general soil-depleting bases, up to 35 percent
of their cotton bases, 30 percent of their tobacco bases, and 20 percent
of their peanut bases. It was determined on a per-acre basis and
averaged approximately $10 an acre for the entire country, varying
quite widely, of course, with variations in the productivity of different
counties and of different farms. Farmers desiring to qualify for the
class 2 or soil-building payment had to adopt certain approved prac-
tices calculated to restore soil fertility.
These practices varied in different parts of the country but gen-
erally included new seedings of legumes and perennial grasses, seeding
of soybeans, cowpeas, etc., for green manure, and applications of lime-
stone. In certain dry areas farmers could qualify for small per-acre
payments if they planted rye as a nurse crop for pasture grasses or if
they strip-fallowed in such a way as to check wind erosion. In some
areas payments were made for terracing. There was a top limit on
the total amount of class 2 payments that a cooperating farmer might
receive, which was generally the same number of dollars as there were
acres of soil-conserving crops on cropland on his farm in 1936. Hence
the larger the acreage of soil-conserving crops on the farm in 1936 the
larger the soil-building allowance. A farmer could earn all or part
of the allowance, in proportion to the extent to which he applied the
recommended practices.
The farmer's response to the agricultural-conservation program
has been gratifying. Although the entire program had. to be
developed after the signing of the Soil Conservation and Domestic
Allotment Act on February 29, more farmers applied for work sheets
or asked for bases to be established than cooperated in the several
commodity programs under the A. A. A. In general the cooperation
was about the same as under the A. A. A. in those areas where corn,
cotton, wheat, and tobacco were the major crops, and much greater
in those areas where general and mixed farming is found, as, for
example, in dairy regions like Wisconsin and New England and the
mixed-farming sections in California. This, of course, was due to the
fact that the new program was much more flexible than the old com-
THE YEAR IN AGRICULTURE 17
modity programs, that it was better regionalized, and that each farm
was considered as a unit.
As already indicated, the primary aim of the new program is the
conservation and improvement of the soil, with crop control an inci-
dental byproduct. With the move next year from a Federal to a State-
aid basis, crop adjustment may become more important. When the
States disburse the soil-conservation grants, soil conservation and crop
adjustment may be combined legally. In fact, the two principles go
naturally together. There was a steady growth of soil conservation
under the original A. A. A. programs, and there should be a similarly
steady growth of crop control when the national program for soil
conservation gets well advanced. For it is obvious that the shift from
soil-depleting to soil-conserving crops answers not only the needs of
the soil but also the needs of the permanent agricultural market.
The shift from soil-depleting cropsj such as cotton, tobacco, and
wheat, to soil-conserving crops, including primarily hay and forage,
may go along with an increase in the animal enterprises commonly
using the latter crops, particularly the beef and dairy enterprises.
This tendency the present drought partially obscures. An increase
in the relative output of these two enterprises, particularly dairying,
appears desirable from the national point of view. But it should be
recognized that farmers in the major dairy areas have long followed
farm practices and cropping systems of a soil-conserving and soil-
building character. Care must be taken not to work a disadvantage
upon them. This problem has been attacked by continued efforts to
secure orderly and stabilized fluid-milk markets through marketing
agreements and orders, through the purchase of price-depressing tem-
porary surpluses and their distribution through relief channels, and
through the elimination of cattle infected with Bang's disease and
tuberculosis. In addition payment for practices of a soil-improving
character enables these farmers to improve their pastures and hay
Long-Time Effects on Production
The present phase of drought-caused shortage can only be tempo-
rary. Under normal weather conditions our agricultural industry can
oversupply its market, and the natural reaction from the present
drought will be for it to do so. For the moment it may seem prema-
ture to talk again about overproduction, but experience proves that
under blind competition one or two good crop years can pile up
surpluses.
It will be well to remember, when overproduction impends, that
soil conservation alone is not a sufficient preventive. Soil-conserva-
tion practices tend to have more effect on output at first than they
do later. In their early stages they reduce the average intensity of
cultivation significantly, and therefore the tendency to oversupply
the market. Eventually, however, they increase soil productivity;
it is obvious, moreover, that less intensive cultivation of part of the
farm area may promote more intensive cultivation of the remainder,
particularly if the farm population is excessive. Unless the foreign
as well as the domestic demand for American agricultural products
revives, the rehabilitation of the soil through soil-conservation pro-
grams will combine with other factors in the agricultural situation
18 YEARBOOK, 1937
to confront the country again in the near future with the absolute
necessity of establishing a good adjustment between production and
market requirements. Permanent agricultural policy should achieve
soil conservation, consumer protection, and crop control together.
The transition from emergency crop adjustments to a more per-
manent program, with good land use and higher current incomes
ranking equally as objectives, began in 1935, nearly a year before
the Supreme Court decided the Hoosac Mills case. It started with
a regional-research project undertaken by this Department in co-
operation with the land-grant colleges and the State experiment
stations.
Farm-management specialists had recognized that a shift toward
less-intensive cropping, accompanied by soil conservation and soil
building would reduce surpluses and at the same time lower the
costs of production. They did not know, however, exactly what
adjustments were necessary in cropping systems. Neither did they
know what the effect of specific regional changes would be on total
production. The research project sought light on these questions.
At the same time that it sought the advice of the experiment sta-
tions, the Department asked farmers for their recommendations.
It did so through a county-planning project, which was in full
swing by the fall of 1936. Committees of farmers were formed in
2,500 agricultural counties throughout the United States. These
committees offered opinions on the same questions that were asked
of the experiment-station specialists. They estimated the county
adjustments apparently necessary in crop and livestock systems to
maintain soil fertility, control erosion, and promote more efficient
farm management.
Specialists in the Department and in the State experiment stations
are summarizing the results. The estimates of the farmers are being
combined by type-of -farming areas, so that they may be compared
directly with the estimates of the experiment station specialists. It
will then be possible to arrive at final estimates which will com-
mand the agreement of both the farmers and the experiment station
group. This year the farmers' committees studied the apparent re-
sults of the soil-conservation program, and offered suggestions for
its improvement.
This work with the farmers and the technical specialists reflects
the Department's recognition of the importance of drawing on the
knowledge and experience of local groups in formulating national
agricultural programs. Eeliance on local interest and cooperation
is more necessary now than ever, because the shift from crop control
to soil conservation enhances the importance of local knowledge and
local action. There was considerable decentralization of adminis-
trative responsibility under the original A. A. A. programs. There
must be considerably more in planning agriculture on the new basis.
In no other way can the procedure be at once efficient and democratic.
METHODS OF EROSION CONTROL
This year's exceptional weather drew attention forcibly to the need
for a regional and local, as well as a national, approach to the prob-
lem of the soil. Floods in the Northeast and elsewhere and dust
THE YEAR IN AGRICULTURE 19
storms in the Great Plains demonstrated that in some areas all the
land should be brought under uniform programs for the control of
erosion. Operations launched under the Soil Conservation and Do-
mestic Allotment Act moved in the desired direction, but the national
approach cannot do everything that is necessary.
There "is need also for intensive local operations in which each
farm may be treated as part of a regional pattern. As is well
known, good soil care on one farm may be counteracted by neglectful
methods on neighboring farms. Efficient soil conservation cannot
be promoted merely by the action of individual farmers ; it requires
coordinated effort through entire land-use regions.
Research, demonstration, and operations in this field are the spe-
cial tasks of the Soil Conservation Service, which was established in
1933 in the Department of the Interior and transferred 2 years later
to the Department of Agriculture. This Bureau cooperates in research
with other Federal agencies as well as with the State agricultural
experiment stations. It cooperates also with the Extension Service
in the development of demonstration projects and in educational
matters relating to erosion control. Essentially the methods of the
Soil Conservation Service are intensive. It makes detailed surveys
and studies the erosion conditions of entire land-use regions as a basis
for specific recommendations and preventive practices.
The studios include topographical and contour mapping, erosion
surveys, soil analyses, observations of land-use practices, and the
testing of different expedients and practices. The demonstration
projects accomplish three distinct purposes : They test various meth-
ods of erosion control, provide demonstrations of the appropriate
methods, and actually prevent erosion on the particular lands in-
volved. All available methods, such as correct cropping and rota-
tions, tillage and engineering practices, moisture conservation, and
pasture and forest development are applied in combination.
Mistaken land-use practices in the United States have caused the
ruin by erosion of some 50,000,000 acres and seriously damaged
50,000,000 acres more. Much additional land is in danger. Soil
erosion injures not merely the owners or the occupants of the eroded
lands and their immediate neighbors; its harmful consequences ex-
tend through whole watersheds and throughout the country. Ero-
sion dissipates fertile soil in dust storms, piles up soil on lower
slopes, covers rich bottom land with poor subsoil, destroys food and
cover for wildlife, and increases flood hazards. Furthermore, it
causes the silting and sedimentation of stream channels, reservoirs,
dams, ditches, and harbors, and damages roads, railways, irrigation
works, power plants, and public water supplies. It is a public
as well as a private liability, and it can be dealt with effectively
only by cooperative endeavor.
Soil Losses Heavy in 1936
Soil losses from the floods last spring were tremendous in the North-
east and in Texas and Colorado. Soil blowing in the Great Plains,
with reduction of the vegetative cover, emphasized the need for a radi-
cal change in the farm system in certain areas, as well as for compre-
20 YEARBOOK, 1937
hensive soil-conserving programs. These conditions brought home to
farmers generally, and to other interested groups, the fact that the
soil problem has distinct regional and local peculiarities, the treatment
of which requires methods appropriate to each region and each local-
ity. Visible damage left by the floods and dust storms was only a
fraction of the total damage, but it emphasized the helplessness of
individual farmers in dealing with conditions that affect entire land-
use regions.
Even in New England, much of which is forest-clad or in pasture,
there is preventable erosion. Perhaps the most serious and widespread
damage in 1936 occurred in the cotton States from North Carolina to
Oklahoma and Texas. Overcropping caused erosion in the Corn Belt
and overgrazing and overplowing were main soil hazards in the Great
Plains. In certain regions the cultivation of steep slopes and the
practice of setting brush fires did great harm. In some localities the
most urgent need is for engineering work such as terraces, check dams,
ditches, and ponds, and in all localities there is need for adjustment
in tillage practices. In some areas the problem is principally one of
clothing denuded slopes with vegetation or of increasing the ratio of
soil-conserving to soil-depleting crops. Everywhere, however, the
problem has local peculiarities which interdict the use of blanket
methods.
In the demonstration projects, 139 of which have been established in
41 States, the Soil Conservation Service begins by marking off a nat-
urally bounded tract about 25,000 acres in extent. (There are three
very large public-land projects in the Southwest and one in Wyoming,
but these are not typical.) Next follow various soil and farm-
management studies, including analyses of cropping systems and
farm-income conditions. The results become the basis for a soil-
conservation plan applicable to the demonstration area, to which the
Soil Conservation Service gives effect by two principal means.
(1) It reaches an understanding with the proper public agencies
that may be involved; then (2) it enters into^ 5-year agreements with
private landowners. Each agreement contains a plan for land use
and appropriate practices, specifies the assistance to be given by the
Service and the proportion of the work to be done by the farmer, and
obligates the operator or owner to maintain for the 5-year period any
improvements that may be constructed and also to follow the agreed
program of cropping and tillage. The Soil Conservation Service also
draws up land-use programs for the entire area, including land not in
farms as well as the land in actual cultivation.
Yet work of this type touches directly only the fringe of the prob-
lem. It covers only a fraction of the Nation's farm land, and directly
involves a comparatively small number of farmers. Compared with
what needs to be, done, the amount of erosion control effected is very
small. Research results and practical recommendations reach a wide
audience through the extension services and find application on mil-
lions of farms in the national soil-conservation programs. Neverthe-
less much remains to be done. There is need for cooperation not only
between the Federal and State agencies but between these agencies
and local farm groups.
THE YEAR IN AGRICULTURE 21
Soil Conservation Associations
Accordingly, besides conducting demonstration projects and car-
rying on similar work with Emergency Conservation Work camps,
the Soil Conservation Service is encouraging soil-conservation asso-
ciations, more than 400 of which have been organized already. Most
of them are on or near areas where there are demonstration projects
or where Emergency Conservation Work projects are under way.
Membership in an association ranges from 10 to 400 farmers. It is
entirely voluntary, and most of the associations have adopted articles
of association without formal organization. They have the legal
status of partnerships for limited purposes. Their members agree
to live up to certain cropping and tillage practices and to cooperate
in operations requiring concerted effort, such as the construction of
terraces, check dams, ponds, and ditches.
There is a fundamental relationship between soil erosion and land-
use practices on both farm and nonfarm land. It does not suffice to
check erosion on farms here and there if other farms nearby continue
to erode. Improper slope cultivation, with consequent heavy erosion,
may ruin a whole valley lower down. In other words, the problem
of preventing soil erosion is a social as well as an individual prob-
lem, and the soil-conservation associations rest on this principle.
The organized farmers of an entire land-use area make a united
attack on a problem which they could not solve individually.
In tackling the problem of the soil, however, voluntary organiza-
tions of the kind above described have obvious limitations. At the re-
quest of State agencies this Department has prepared a standard State
conservation-districts law to serve as a recommendation regarding
the nature of appropriate legislation, which, if enacted by State leg-
islatures, would authorize the formation of public agencies with
power to enter into agreement with farmers relating to the perform-
ance of appropriate control operations on eroding lands, and in case
of majority vote, to establish land-use regulations. Texas has passed
such legislation, providing authority to wind-erosion districts to ex-
pend funds and carry on work on lands not properly treated by the
owners. In that State 14 conservation districts have been organized.
Several other States are considering the enactment of similar laws
at the next sessions of their legislatures.
The standard measure provides that proposed land-use regulations
must be submitted to a referendum of the land occupiers and may not
be enacted without a favorable majority vote. Once approved, the
regulations would be binding on all lands within the district. There
are provisions for notice, hearing, referenda, administrative appeal,
and judicial review. No district could be organized without a
majority in favor of it, and no specific regulation could be imposed
without a referendum.
Boundaries of the conservation districts would be determined by
a State soil-conservation committee, which could not act, however,
until a petition had been filed with it by at least 25 farmers and until
a public hearing had been held. The committee would fix the dis-
trict boundaries by a State plan, drawn up to indicate the soil, the
topography, and the types of farming. Once organized, the dis-
22 YEARBOOK, 1937
trict would have the authority to accept funds and services and
otherwise to cooperate with Governmental agencies in the develop-
ment of plans and programs for the district.
It would receive an annual appropriation from the State legisla-
ture, and technical and other assistance from both State and Federal
agencies. It would have the power to make intensive studies of its
territory and to contract with farmers for the performance of neces-
sary control work. Wide adoption of this plan would provide the,
opportunity to develop erosion-control operations on an intensive
local basis as a useful and, indeed, necessary complement to the more
general agricultural conservation program instituted under the Soil
Conservation and Domestic Allotment Act.
Land Use and Flood Control
In the Flood Control Act, which was approved June 22, 1986,
Congress recognized the importance of land-use methods in flood con-
trol. Floods, of course, are erosion phenomena. They waste soil as
well as water. The new law provides that Federal investigation of
watersheds, measures for run-off and water-flow regulation, and meas-
ures for the prevention of soil erosion on watersheds shall be instituted
by the Department of Agriculture. Studies and projects relating to
the improvement of rivers and other waterways for flood control are
the responsibility of the War Department. The act declares it to be
the sense of Congress that flood control on navigable waters or their
tributaries is a proper activity of the Federal Government in coopera-
tion with the States and their political subdivisions, and that investi-
gations looking to the protection of watersheds are in the general
welfare. Thus the act emphasizes the complexity of the flood problem
and points to the necessity for an approach to it from an agricultural
as well as from an engineering standpoint.
LAND POLICY
It is coming to be generally recognized that the cornerstone of a
sound national economy is a rational land policy. The droughts of
recent years, with the resulting soil blowing and dust storms, have
focused attention on the need of long-time land-use planning. Need-
less to say, wind erosion is not the only indication of the need. Forest
devastation, the progress of soil erosion by water, the wide extent of
submarginal farming on land unsuited to farming, the growing
seriousness of tenure problems in many areas, and the prevalence of
destructive cropping and overgrazing are a few of the problems
which betoken the want of a coordinated land policy. Fortunately
we have made a good start in recent years toward the development of
a socially desirable land-utilization program.
The Resettlement Administration has begun to acquire poor farm
lands and to promote their development for other uses. It has also
aided farm people in some areas to find better locations. In the last
fiscal year the Resettlement Administration obtained options on
9,500,000 acres of poor farm land in 207 projects. On the bulk of
this acreage the Administration took up the options at an average
price of about $4.50 an acre. Approximately $38,000,000 has been
already allotted for the conservational development of these lands,
THE YEAR IN AGRICULTURE 23
and the undertaking gave employment to as many as 55,000 relief
workers.
Among the 207 projects 46 were sponsored by the National Park
Service of the Department of the Interior. These will be developed
for recreational purposes. The Bureau of Biological Survey has
sponsored 32 of the projects for the propagation and protection of
migratory waterfowl. The Indian Service has sponsored 31 projects
to provide more land for Indians. The Resettlement Administra-
tion has sponsored 96 projects primarily of an agricultural charac-
ter, though some of them include recreation, wildlife, and forestry
aspects. In its resettlement activities the Resettlement Adminis-
tration has approved 97 projects calling for the purchase of 730,000
acres of land and the building of homes for 13,255 families. Funds
are now available for the construction of 40 of these projects. In
addition there are 43 subsistence-homestead communities either
completed or in process of completion.
As noted elsewhere in this report, the Bureau of Biological Survey
has acquired considerable land for the preservation and conserva-
tion of wildlife. Prior to 1933 it had purchased 215,365 acres with
funds appropriated to it by Congress. These lands formed the
nucleus for 11 wildlife refuges, within which, however, additional
lands were needed. Since 1933 the Biological Survey has purchased
considerably more land with emergency funds made available
through the Resettlement Administration. On July 1 about 893,000
acres in 42 refuge units had been, or were being, acquired at a total
land cost of $5,359,254. Another important aspect of the national
land policy is being developed under the Taylor Grazing Act, which
Congress amended last year in important respects. One amendment
enlarged (from 80,000,000 to 142,000,000 acres) the area of vacant
unappropriated and unreserved lands of the public domain available
for the creation of grazing districts under the act, which is ad-
ministered by the Department of the Interior.
Land settlement, as well as the diversion of poor farm land to
other uses, forms an integral part of the national land policy. Land
settlement or resettlement will doubtless continue as long as we have
suitable land available. Between 1930 and 1935, according to the
Census of Agriculture, the number of farms in the country increased
by approximately half a million. This is an indication of the extent
to which farming has cushioned th& shock of the industrial depres-
sion. Industrial workers have established many of the new farms
in and near industrial centers, but a larger proportion of the in-
crease has resulted from the fact that in the depression years the
natural increase of the farm population could not find nonfarm
employment. The new farms have developed largely on self-suffic-
ing lines. Part-time farming underwent considerable development.
Numbers of industrial workers acquired small plots near their work.
They produced some of their own food and something to sell besides,
and reduced their living expenses in other ways. Many suburban
families started small-scale farming without moving. Some of them
were able to rent land near their homes. This whole movement
caused the census to classify as farms many places which previously
it had not so classified.
24 YEARBOOK, 1937
Return Migration to Submarginal Lands
Another major type of recent land settlement is taking place on
the poorer farm lands in several regions. In these areas, the chief
of which are the southern Appalachian, the Lake States cut-over,
and the Ozarks, considerable migration and farm abandonment had
previously taken place. After 1930, however, many of the people
who had gone away returned. They had lost their city jobs, and
their former farm homes offered them at least a subsistence. But
in some areas the part-time nonfarm work that had previously been
available could no longer be obtained. Many lumbering and mining
industries had collapsed. As a result the rural folk had to depend
more than ever upon farming. The number of both part-time and
full-time farmers increased. Furthermore, these areas have normally
a high birth rate and there was no place for the rising generation to
go. In consequence the rate of increase in the number of farms was
greater in these areas than over the country as- a whole. As a matter
of fact, there was relatively little new settlement in the better com-
mercial farming areas. In some such areas, indeed, as for example
in central Indiana and Illinois, the farm population decreased, and
farms became larger.
This tendency toward an increase in the number of farms in poor
farm areas inevitably created difficult problems. It is not an easy
matter to start a new farm and get it well established even in good
times. In hard times, particularly where the land is poor and where
the settlers have little money, the obstacles are greater. Many
farmers who returned to their former homes, or who took up other
land, found themselves unable to make ends meet.
Small, poor farms inadequately stocked and equipped do not fur-
nish an easy livelihood, and the occupants will be quick to move
when better prospects appear. The Resettlement Administration is
studying the problem and, where possible, is providing opportuni-
ties for the relocation of farm families on land better suited to their
needs. The creation of new farms in regions of poor land, where
soil depletion is serious and where the standard of public services
is low, simply means the creation of rural slums. The new farms
established in the last few years have commonly been smaller and
poorer than the old ones, and sufficient additional part-time work
can seldom be had. Resettlement alone cannot cure the trouble,
though it may help. More is to be hoped for from the revival of
industry, which will tend to lessen the pressure of population on the
land; but unless employment opportunities in industry can be sta-
bilized we shall continue to face the problems created by the periodic
swings of a large segment of our rural population back and forth
between country and city, moving cityward in good times and coun-
tryward in periods of depression.
The development of better land use is largely dependent on the
improvement of land-tenure systems. Most people now recognize
that not all the land should be in private hands. Public ownership
is better for parks, for various recreational uses, for wildlife refuges,
and frequently for forests. Certain types of grasslands, as well as
forest lands, can be best managed as public property. These facts,
THE YEAR IN AGRICULTURE 25
which scarcely anyone now denies, do not warrant going to extremes
in the public ownership of land resources. They simply indicate that
the public ownership of land has a place in a good land system, and
that tradition and custom should not be allowed to block reform.
There are good and bad methods of private ownership. Certain
widely established practices stimulate unwise speculation, soil min-
ing, absentee landlordism, and excessively high rates of tenancy.
These are not the inseparable and unavoidable results of private
ownership. Methods can be developed which tend to minimize them,
as the experience of some other countries amply demonstrates. Our
traditional land-tenure system has shortcomings which can be
remedied without changing its fundamental character. But it is
necessary to recognize that there are different types of land, some
of which can best be used as private property and some of which
can best be used in public ownership.
Conditions Peculiar to United States
It is necessary also to recognize that the tenure practices developed
in this country are not the only practices available. Our methods of
private ownership have developed tenancy conditions very different
from those of some other countries. Thousands of our farm tenants
change their farms every year, and thousands more have only the
semblance of security in their tenure. Few tenant farmers, except
those who occupy the farms of relatives, can be sure of operating
their farms for longer than the period covered by the lease, which
is generally for only one crop-year. Moreover, they have no stake
in any improvements which they may make on the farms. If they
keep the buildings and equipment in good repair and build up the
soil through good tillage or the application of fertilizer, or if they
prevent erosion by terracing or other methods, they may have their
rent raised. Should they be forced to leave they will not be com-
pensated for the improvements. This fact discourages tenants from
making farm improvements and from conserving the soil. The new
Soil Conservation and Domestic Allotment Act is seriously handi-
capped in its application to tenant farmers by these difficulties.
Other countries have taken steps to reduce tenancy or to change
and improve it, and eventually the^ United States must do the same.
It must face the problem of providing security for its great mass
of landless farm people. The farm census of 1935 reported about
2,865,000 tenant farmers, whose families aggregated 12,500,000 people.
This was the largest number of tenant farmers ever reported by the
census. In most States the percentage of tenancy increased signifi-
cantly between 1930 and 1935. In certain areas more than two-
thirds of the farm operators are tenants. Many of them frequently
shift from farm to farm to the injury of the land, to the deteriora-
tion of community institutions, and to the decline of their own
morale. Also, our farm population includes several million farm
laborers, a large proportion of whom lead a migratory life, with
only casual and uncertain employment. This group, as well as the
tenants, should be considered in our land policy.
This Department, in cooperation with the Kesettlement Adminis-
tration and other agencies, is studying ways and means of improving
138004°— 3T 3 ++
26 YEARBOOK, 1937
the tenancy system. The problem is national in scope and of tre-
mendous importance. In some areas an acceptable remedy would be
a more widespread diffusion of farm ownership provided such own-
ership can be protected from the worst vicissitudes of our economic
life. One of the Resettlement Administration's projects seeks to aid
1,000 southern tenants to become farm owners. Then there are ways
of improving leasing agreements. It should be possible to do so with
advantage to landlords as well as tenants. The problem is to reshape
our land-tenure system so as to promote a type of agriculture cal-
culated to conserve the soil, to give the cultivator a more secure oc-
cupancy of his farm, to maintain the existing capital investment in
farm buildings and farm improvements, and to promote the develop-
ment of sound rural institutions. Most of the necessary steps will
require legislative action, both State and Federal. The whole prob-
lem requires statesmanlike treatment.
Farm-Land Values
Farm-land values increased for the third successive year during the
year ended March 1, 1936. This gain, of course, reflected continued
improvement in agricultural conditions. Not only were valuations
higher, but the farm-land market indicated increased interest on the
part of prospective farm buyers, particularly in the East North Cen-
tral and Pacific States. The number of farms purchased increased
considerably. With the equities of farm owners rising, loan compa-
nies showed more willingness to finance sales; sellers raised their
asking prices, and creditor agencies found themselves able to dispose
of more farms. Tenants showed a definite interest in buying farms.
This Department's index of the value per acre of farm real estate
rose during the period mentioned from 79 to 82 percent of
the pre-war level. Gains were far more general than in either of the
2 preceding years. All States but two reported some increase. Dur-
ing the preceding year only 31 States reported rising values. As a
group the Corn Belt States reported the greatest average increase,
nearly 8 percent. States in the wheat region and grazing area of the
West averaged 5-percent gains. The Cotton Belt States averaged
3 percent; the hay and dairy States averaged 2 percent. For 11
States the index was above the pre-war basis. Four of these States
were in New England ; one in the Middle Atlantic group of States ;
five in the South, and one on the Pacific coast.
There were favorable changes in the frequency of transfer. For
the country as a whole the number of farms transferred as a result
of debt difficulties was a little smaller than during the preceding
year, though the decline was not uniform. In fact, in a number of
States such transfers increased. For the country as a whole, how-
ever, forced transfers associated with debt declined from an esti-
mated frequency of 21.0 to 20.3 per thousand of all farms. The
number of voluntary transfers showed a definite upturn and reached
levels comparing favorably with those of the years immediately pre-
ceding the depression. This gain, though somewhat encouraging,
did not indicate that a whollv normal farm real-estate market had
become reestablished. Creditor agencies still had many farms which
THE YEAR IN AGRICULTURE 27
they were anxious to sell. Nevertheless, the emergency phases of
land financing declined in importance.
From the standpoint of the individual farmer attention now shifts
to making good on present loans and to securing normal financing
at reasonable cost. The Farm Credit Administration is giving sub-
stantial help. Its activities in refinancing, in the deferring of pay-
ments on principal, in the granting of extensions in facilitating the
handling of distressed mortgage debts, and in reducing interest
costs to farmers are important factors in the improvement of the
farm real-estate situation, as well as in tbe improvement of agri-
culture as a whole. How effective this work has been can be seen
in the decline in the number of farmers who need aid in preventing
foreclosures and also in the decline in the number of extensions
granted. Also, collections on loans held by the land banks are im-
proving. The important task now is to develop a farm-mortgage
system that will be more nearly shock proof than the system that
existed before the depression.
FOREIGN TRADE IN FARM PRODUCTS
Farm products participated in the general increase which took
place during the past fiscal year in ail branches of United States
foreign trade. This was true both of farm imports and farm ex-
ports, in spite of certain distorting influences that tended to enlarge
the imports and diminish the exports. Chief of the abnormal forces
was the persistent effect of the 1934 drought and a flight of capital
into the United States from other countries. General business re-
covery, together with the influence of the reciprocal trade agreement
program, benefited the farm export trade materially.
Exports of United States farm products rose from 669 million
dollars in the fiscal year 1935 to 767 millions in 1936. Imports of
farm products (including coffee, rubber, silk, and many other exotic
products) rose from 971 million dollars in 1934-35 to 1,185 million
dollars in 1935-36. As compared with the low points of 590 mil-
lion dollars in exports and 612 million dollars in imports during
1932-33, the increases seem large, but neither the exports nor the
imports of farm products were near the levels maintained from
1920 to 1929.
Substantially larger shipments of cotton, tobacco, and fresh and
dried fruits were mainly responsible for the improvement in the
exports. Our exports of cotton, including linters, totaled 6,702,000
(500-pound) bales, as compared with 5,328,000 bales the preceding
year. Leaf -tobacco exports amounted to 417,539,000 pounds, against
353,347,000 pounds the year before. Improvement in the exports of
fresh and dried fruits, practically all classes of which showed sub-
stantial gains, was in part a result of foreign duty reductions brought
about under the reciprocal trade agreement program. Exports of
lard, cured pork, and wheat, continued to reflect the reduction in
supplies caused by the drought of 1934 and by heavy rust damage to
wheat in 1935. Lard exports fell to the lowest figure in recent years.
There were practically no exports of domestically produced wheat.
An important part of the increase in the agricultural imports was
the so-called competitive products. It is necessary to distinguish
28 YEARBOOK, 1937
between products like sugar and wool, of which we regularly import
a great part of our supplies, and products such as corn, wheat, and
rye which we import in significant amounts only under exceptional
conditions. Most of the increase after 1932 in the value of our com-
petitive agricultural . imports was in the regularly imported items,
which tend to be imported in greater quantities as economic condi-
tions improve. But some of it in the last fiscal year was in grain and
feeds, meats, dairy products, and eggs, the domestic production of
which had been reduced by the 1934 drought. Imports of this char-
acter reached their peak during the first quarter of the fiscal year
and then declined. The 1936 drought may again increase the imports
of these products.
Another important distinction exists between noncompetitive im-
ports and imports similar to commodities produced in the United
States. Our total agricultural imports in 1935 amounted to 1,073
million dollars.1 Of this amount 483 million dollars, or 45 percent,
consisted of noncompetitive items, like coffee, rubber, raw silk,
bananas, spices, cocoa, and tea. There remained 590 million dollars'
worth of imports similar to or capable of being directly substituted
for our own agricultural products. About 134 million dollars' worth
of sugar came in under strict quantitative limitations and cannot
properly be deemed competitive. Subtracting the sugar leaves only
456 million dollars in competitive imports, or about 42 percent of the
total of all agricultural products imported during the calendar year
1935. This total may be compared with our farm export total of 747
million dollars during the same period.
Significance of Competitive Imports
Despite the domestic shortage of certain farm products, our im-
ports of competitive commodities were less than two-thirds as high as
the annual, average for the decade preceding the depression. In
most cases they represented an insignificant proportion of our normal
output of similar products. They fell far short of offsetting the defi-
cits left by the drought. Imports of corn in 1935 amounted to only
1.7 percent of our average annual corn production from 1928 to 1932.
Wheat imports were 3.2 percent of the average production, oat im-
ports only 0.8 percent, barley imports 4.7 percent, pork imports 0.1
percent, and beef imports of all kinds only 3 percent.
The drought of 1934 caused a reduction of 50 million tons from
our average production of feed in the United States. In the year
and a half from July 1934 to December 1935, imports of feed and
fodders of all types amounted to less than Sy2 million tons, or only
7 percent of the shortage. Imports made up only a trifling part
of the loss in production caused by the drought. The same was true
of wheat, meat, and dairy products. Farmers met the feed shortage
not primarily by imports, but by lighter feeding of animals, earlier
and heavier pasturing, and heavy marketing for slaughter.
As a result of this year's drought we may have to import some
feed. This is the logical procedure, good for both producers and
consumers. Agriculture's problem is not how to stop a moderate
1 Excluding distilled liquors.
THE YEAR IN AGRICULTURE 29
flow of competitive imports following a crop failure but how to plan
for its normal conditions, which are those of a surplus country. Nor-
mally, American agriculture encounters its major foreign competi-
tion abroad. It produces for export; and temporary shortages in-
duced by drought should not hide the fact that an import-exclusion
policy would react adversely on the export trade. Besides hurting
the farmers, who must purchase feed in short-crop years, such a
policy would permanently injure those who grow cotton, tobacco,
wheat, hogs, and fruit.
In the balance of international payments of the United States for
1935 the increase in imports, which consisted of agricultural products
brought in to relieve the drought emergency, tended to obscure the
persistent unbalance between our import and export trade. As a
result of these unusual temporary imports, our excess of exports was
only $236,000,000. While that figure is at about the level of the
balances during 1932 and 1933, it is lower than that for any other
year since the World War. The apparent approach of our merchan-
dise trade to an approximate balance, however, is illusory. It will
probably be reversed as soon as we have normal crops unless the
trade-agreements program greatly increases our imports of foreign
industrial specialties. The largest single factor in the balance of pay-
ments for 1935 was the continuing flight of capital from Europe and
elsewhere to the United States. This movement of capital tended,
of course, temporarily to hide the necessity for increasing our imports.
Reciprocal Trade Agreements
Agriculture is beginning to benefit from the Reciprocal Tariff Act.
During the last fiscal year the United States concluded reciprocal
trade agreements with nine countries, namely, . Colombia, Canada,
Honduras, the Netherlands, Switzerland, Nicaragua, Guatemala,
France, and Finland. It had entered previously into similar
agreements with Cuba, Brazil, Belgium, Haiti, and Sweden. All
14 agreements are in effect except those with Finland and Nicaragua.
It is difficult to measure the results as yet. Most of the agreements
have not been long in effect and the period covered by their operation
has been one of abnormally low production in the United States.
Moreover, the countries with which agreements have been concluded
ordinarily take only about a quarter of our total agricultural exports.
It will not be possible fully to test the reciprocal trade-agreement
program until agreements have been concluded with one or more of
the countries that constitute our leading foreign markets, namely,
the United Kingdom, Germany, and Japan.
Foreign countries have made important concessions on United
States agricultural products. The agreement with Cuba substan-
tially reduced that country's duties on American lard, potatoes, rice,
and many other products. Canada reduced its duties on cured pork
and lard and on a long list of fruits and vegetables. European
concessions include lower import duties and larger import quotas
on a long list of commodities and are particularly helpful to our
fruits. France has made important concessions as Avell on American
tobacco, and several countries have relaxed their restrictions on im-
ports of American lard and wheat. Cotton, our leading agricultural
30 YEARBOOK, 1937
export, can benefit only indirectly from the trade agreements, be-
cause the foreign countries with which tariff reductions can be ob-
tained through such agreements do not impose serious restrictions
on cotton. Most of the countries with which agreements have been
concluded admit our cotton either duty-free or at low rates.
The reciprocal concessions which the United States has made help
our exports by aiding foreign countries to get dollar exchange. We
have made a few concessions on agricultural products. Few of
them, however, were in effect during recent increase in agricultural
imports. Negotiating the agreements the United States has kept two
principles in mind: (1) That the import duties should not be re-
duced below the rates prevailing prior to the enactment of the dis-
astrous Tariff Act of 1930; and (2) that on products of primary
importance the reductions should be safeguarded either by seasonal
limitations or by import quotas.
In the Cuban agreement, for example, the duties on vegetables are
reduced for a limited period during which our own supplies are small.
In the Canadian agreement the duty reductions on cattle, seed pota-
toes, and cream apply to strictly limited quantities. The only impor-
tant agricultural items on which duty reductions have been made
without some such safeguard are various types of cheese and imported
wrapper tobacco. But the duties on cheese have not been reduced
below the rate prevailing previous to the Tariff Act of 1930, and most
of the types of cheese concerned are not produced commercially in
this country. As for wrapper tobacco, few American farmers grow
it, while many thousands produce the filler and binder tobacco which
has to be combined with the imported article.
Concessions by the United States
Most of the tariff concessions made by the United States are reduc-
tions on specialized industrial items or agreements to keep on the free
list noncompetitive products such as coffee, cocoa, and bananas.
Other countries have made concessions to us on industrial products;
and the advantage goes to American farmers as well as American
manufacturers. Increased industrial exports mean more buying of
farm products.
Broadly speaking, there are three types of reciprocal-trade agree-
ments: (1) Bilateral arrangements for the exchange of exclusive con-
cessions with individual countries, (2) arrangements based on condi-
tional most-favored-nation treatment, and (3) arrangements based on
unconditional most-favored-nation treatment. The United States has
favored the third method, and it may be useful to glance at the
reasons.
(1) The strictly bilateral approach is open to the objection that it
would reduce our foreign trade. In our trade with most countries we
export more than we import. To equalize matters with these nations
individually would require a reduction in our exports. This has been
the experience of European countries that have tried to achieve
bilateral balances of trade. Under our present policy triangular and
multiangular trading squares matters. It enables countries that buy
more than they sell here to even things up by transactions with other
countries which in turn may divert products to the United States.
THE YEAR IN AGRICULTURE 31
(2) Under the second approach, the conditional most-favored-nation
treatment, reciprocal concessions might be granted to countries that
made equivalent concessions to us. But this method, too, tends to
decrease the total trade. Few countries other than the parties to an
agreement will be equally interested in the same commodities and
duty reductions. Most countries will therefore be unwilling to make
the equivalent concessions required. Moreover, they will object to
discriminatory tariff treatment and may retaliate with higher duties
against our goods.
The result may be a tariff war and new obstacles to international
trade. Even without retaliatory measures discriminatory treat-
ment under the conditional principle may force trade into more
restricted channels. Changes in foreign trade affect the domestic
markets.
(3) The third or unconditional most-favored-nation approach has
been followed by the United States in all cases except that of Cuba,
under the present trade-agreement program. This is the policy re-
quired by the Eeciprocal Trade Agreements Act, which directs the
Government to grant any tariff reductions to all countries except
those that discriminate against the commerce of the United States.
Under this last restriction Germany and Australia have been denied
the benefit of most-favored-nation treatment, but all other coun-
tries receive it. The unconditional most-favored-nation treatment,
which has been followed by the United States since 1922, has the
great advantage of affording a guarantee of no discrimination against
us in our foreign markets.
In negotiating the Brazilian agreement the United States did not
get a reduction in the Brazilian duty on wheat flour. Subsequently,
however, the Brazilian Government reduced its flour tariff on its
own initiative. The unconditional most-favored-nation clause in
our trade agreement with Brazil gave the benefit of this reduction
automatically to the United States, as well as to other countries.
Conversely, Germany has been unwilling to come to an uncondi-
tional most-favored-nation understanding with the United States.
As a result we have lost part of our market for agricultural
products in that country.
What Should We Import?
In deciding the kind of imports that we should encourage under
reciprocal-trade agreements it is important to remember that the
United States tariff has had its greatest effect in the past in pre-
venting imports of industrial products, and therefore in raising the
prices of the things that farmers buy. The domestic market for most
industrial products is relatively elastic, whereas the domestic market
for most agricultural products is relatively inelastic. Many existing
tariffs merely serve to bolster industrial monopolies, which use their
advantage to obtain high prices. The major markets for United
States farm exports are to be found in industrial producing countries
such as Great Britain, Germany, and Japan. If the trade-agree-
ments program is to go forward successfully we must conclude agree-
ments with the large industrial countries and offer reductions in our
duties on manufactured products.
32 YEARBOOK, 1937
THE 1936 CROPS
The year 1936 ranks next to 1934 as the most disastrous season for
crops in the history of the country. Kecords going back to the
early 1860's include no seasons comparable with 1936 and 1934 in
loss of acreage and reduction of yields. Both years brought great
droughts. This year's drought reduced crop production to about
one-fourth less than the usual output; whereas the drought of 1934
reduced it to about one-third less.
Geographically, there was a striking resemblance between the two
droughts. They were particularly severe in the whole area stretch-
ing from North Dakota and eastern Montana to north -central Texas,
and extending eastward over Missouri, southwestern Illinois, south-
ern and western Iowa, and west-central Minnesota. Northeastern
Wyoming, parts of eastern Colorado, northeastern New Mexico,
and northwestern Arkansas also suffered severely in both years. In
both seasons the production of wheat, corn, oats, barley, rye, and
grain sorghums was greatly reduced ; but in 1936, except in limited
areas, there was no repetition of the acute shortage of hay and
roughage that caused so much trouble in 1934.
Corn production in 1936, as a result of the drought, was slightly
smaller than that of 1934 and was the smallest corn crop harvested
since 1881, when our population was only 40 percent of what it is
today. Of the eight States which usually produce two-thirds of the
total corn crop seven had even less rainfall during the summer
months than they had in 1934. The corn crop was particularly poor
in the Dakotas, Nebraska, Kansas, Missouri, and Oklahoma. In
these States the acreage that could be harvested for grain was largely
limited to the river bottoms, to areas favored by local showers, and
to irrigated sections. Much of the crop was cut early for forage
and silage or was pastured by livestock. Grasshopper damage was
severe in some areas and in these localities crops had little value
even for fodder. Present indications are that the total corn crop is
only about 1,458,000,000 bushels as compared with an average of
2,553,000,000 bushels for the period 1928 to 1932.
About one-fourth of the acreage seeded to winter wheat was a loss
as a result principally of drought conditions. Scarcely more than
half of the seeded spring wheat acreage was harvested for grain.
The total wheat production was only about 630,000,000 bushels. This
is more than was produced in any of the preceding 3 years, all of
which were very unfavorable, but less than the production of any
other year since 1917. Rye suffered likewise. Abnormally high
temperatures and drought combined reduced oat yields in practically
all the important oats-producing States except those along the Pacific
coast, and in some States caused nearly a total loss of the crop. Oats
production is estimated at 777,000,000 bushels, or about two-thirds of
the usual production. However, it was about 43 percent greater than
the very short oat crop of 1934 and slightly above the crop of 1933,
though below the production in any other year since 1896. The bar-
ley crop was reduced by one-half. It is estimated at 145,000,000
bushels, as compared with 282,000,000 bushels in 1935. Production
of grain sorghums is estimated at 59,000,000 bushels, as compared
with 97,800,000 bushels in 1935.
THE YEAR IN AGRICULTURE 33
The Feed-Grain Supply
Production of com, oats, barley, and grain sorghums combined is
only about 58,000,000 tons, as compared with 93,000,000 in 1935, and
54,000,000 in 1934. In other years since the World War the combined
production of these grains has averaged 100,000,000 tons and has
ranged from 85,000,000 to 117,000,000. Reserves of grain on land
will be closely utilized and net imports of grain and feedstuff's may
have to be increased somewhat ; but most of the shortage will be met
by feeding hogs less grain than usual.
There is a fair supply of hay and roughage. Hay production is
only about 10 percent below the average. In 1935, three-fourths of
the States had hay crops above the average, and the supply of old
hay on farms at the beginning of the season was rather large. But
many farmers had to use some of their old hay this summer. By
utilizing straw, fodder, and other roughage a little more closely than
usual and by using part of their reserves, farmers will be able to feed
nearly the usual quantity of hay per unit of livestock.
Rice, sugar beets, and irrigated crops generally gave good yields.
So did cotton and peanuts east of the Mississippi River. Tobacco,
with yields about the average, was moderately light, drought having
prevented expansion of the acreage. The buckwheat crop was the
smallest since the Civil War. Drought damaged it severely in prac-
tically all producing States. Flaxseed production, though greater
than in 1934, was below that of any other season in 60 years. Potato
production was below average and sweetpotatoes about an average
crop. As noted elsewhere in this report there was a fair supply of
commercial vegetables and a light pack of most canning vegetables
except tomatoes.
WEATHER CONDITIONS OF 1936
Weather conditions in the United States in 1936 were extremely
abnormal. During the spring months they produced unprecedented
floods in the Eastern States, bad dust storms in the Middle West, and
destructive tornadoes in the South. Later the most severe drought of
record developed in the interior States. The drought was the third
in recent years, others of tremendous national significance having
occurred in 1930 and 1934. This year's drought, besides causing
enormous damage to crops, inflicted great hardship on farm people
throughout an immense area, particularly in States that had not
recovered from the drought of 1934. It aroused fears among some
people that our climate might be undergoing a permanent change,
though there is no scientific evidence that such is the case, and led
to speculation as to whether recent conditions might possibly be due
to some human activity. Various suggestions for preventing drought
have been made. In general these suggestions fail to distinguish be-
tween basic changes in climate and proposals for mitigating or pre-
venting some of its untoward effects. It will be interesting, after
glancing at what the weather did to us in 1936, to notice what mete-
orological science has to say about the causes of floods and droughts —
for both floods and drought have a common origin in the natural laws
that govern evaporation and precipitation.
34 YEARBOOK, 193 7
The floods in the Eastern States followed a severe winter, accom-
panied by the heaviest snowfall in many years in the country north of
the Potomac, the Ohio, and the Missouri Rivers. Mild, rainy weather
late in February and early in March caused rises and ice gorges in
the rivers of New England and the Middle Atlantic States. About
March 17 heavy rains fell on well-saturated and semifrozen soil, and
the percentage of run-off was unusually high. Moreover, the north-
ern rivers were at or above flood stage, and those in Maryland and
Virginia, while not in flood, were higher than normal.
The result was disastrous floods in the James, the Potomac, the
Susquehanna, the Connecticut, and the Merrimack Rivers, in some of
the tributaries of the Ohio River, in Pennsylvania, and in the Ohio
from Pittsburgh, Pa., to below Wheeling, W. Va. The Ohio River
flood gave a record crest stage of 46.0 feet at Pittsburgh on March 18.
The previous high-water record was 38.7 feet on March 15, 1907.
Flood damage in the Northeastern States was undoubtedly the great-
est of record. Many houses were destroyed, and business was par-
tially or completely paralyzed in many industrial areas. Losses to
wage earners and retailers were heavy.
The weather of 1936 was decidedly unfavorable for agriculture
over the greater portion of the United States. Precipitation in the
winter and early spring was very scanty in the Southwest, where the
soil became extremely dry, and severe dust storms caused much dam-
age. In May, however, there came abnormally heavy rains, which
were especially helpful to winter wheat over large areas, particularly
in Kansas. Other parts of the country were less fortunate. Serious
conditions developed over large areas. Dry weather in May and
June brought widespread damage to early truck, hay, and pastures.
Spring Exceptionally Dry
The spring was the driest of record in many southeastern localities.
Great harm resulted to early crops in considerable areas, especially
from North Carolina southward and southwestward to central Ala-
bama. The winter-wheat crop, however, was not seriously affected,
principally because of May rains in the western portion of the Wheat
Belt and comparatively cool weather in the eastern part. Some
deterioration of the crop occurred, especially in northern districts.
The spring-wheat crop and other small grains in the Northwest were
severely damaged. The livestock situation became desperate. Over
large areas there was neither feed nor sufficient water available.
However, conditions continued favorable in the North Pacific States.
The summer was abnormally hot and dry in all Central and North-
ern States between the Appalachian and Rocky Mountains. July had
less than 10 percent of normal rainfall in considerable areas; there
Avas less than half of normal (usually much less) in the western part
of the Ohio Valley, the Great Lakes region, the upper Mississippi
Valley, and throughout the Plains from Oklahoma northward to
North Dakota and Montana. The States from Oklahoma northward
to North Dakota had only from 20 to 36 percent of normal ; Minnesota
had about 20 percent ; and Iowa less than 15 percent. July 1936 was
drier than July 1934 in every State from Kentucky, Missouri, and
Oklahoma northward to the Canadian border.
THE YEAR IN AGRICULTURE 35
The months of Juno and July combined had an average of only
about one-third of normal rainfall in the Plains States and about 40
percent of normal in the western Ohio and middle Mississippi Valleys.
In the interior States the 2-month period was much drier than the
same 2 months during the great drought of 1934. Abnormally high
temperatures aggravated the effect of the deficient moisture.
The 4 months of the growing season up to the end of July were the
driest of record in the Dakotas, Minnesota, Wisconsin, Iowa, Missouri,
Illinois, and Indiana, and the second driest in Ohio, Kentucky, Okla-
homa, Kansas, and Montana. Of the Central and Northern States
between the Appalachian and Rocky Mountains, only Michigan,
Kansas, and Nebraska were drier in 1934 than this year for these 4
months.
The weather during August, for the most part, continued decidedly
unfavorable throughout the central valleys, with afternoon tempera-
tures in many places reaching 100° F. or higher nearly every day.
Lower temperatures and rather frequent showers were decidedly help-
ful in northern sections from New England westward to the Great
Plains, including considerable portions of the eastern and northern
Ohio Valley and some upper Mississippi Valley sections. However,
during this month the drought extended southward to Texas, Arkan-
sas, northern Louisiana, Mississippi, and Tennessee.
THE CAUSE OF DROUGHTS
There are two basic principles in rain production — evaporation
which charges the air with moisture, and condensation, which re-
leases it. The first is important, but the latter much more so in con-
nection with droughts. The only way rain can be produced in ap-
preciable amounts is by the air, including the invisible vapor of
water, becoming cooled on a large scale. Cooling causes condensa-
tion because warm air can hold more moisture, more water vapor,
per unit volume than cool air. The capacity of air, or rather of
space, for holding invisible moisture doubles Avith each increase of
20° F. in temperature. Tims, a cubic foot of saturated air at 80° F.,
if cooled down to 60° F., must lose by condensation half of its water
content, which appears as cloud and rain.
Air cools when rising because it comes under less and less pres-
sure, and therefore expands; the normal fall in temperature for an
ascending column of air is 1° for each 183 feet of rise. Nature
effects this method of cooling in a number of ways, usually on an
immense scale. Air moves from place to place over the earth's sur-
face in mass formation. These masses come from two main regions —
polar and tropical. Those from the Poles are dense, heavy, and
relatively cold; those from the Tropics are warmer and lighter.
When polar and tropical air masses meet, the tropical air, being
lighter, naturally flows up over the opposing dense air, just as it
would flow up a mountain side. As it ascends it expands and cools,
and the water vapor is cooled enough to condense and fall as rain.
Cooling the water vapor in this way is nature's method of producing
rain in appreciable amounts. It is the only effective way.
When the normal courses of these opposing air masses are dis-
rupted for a considerable period, abnormal conditions, such as
36 YEARBOOK, 1937
droughts, result. These processes have a world-wide relation. Na-
ture's weather factory is the whole world, and some of its operations
have not yet been discovered. Just how and why these abnormal
conditions establish themselves and persist so long, meterologists
have not determined. Enough is known, however, to make ridiculous
any suggestions that men can basically change the order of things.
New Methods in Weather Forecasting
It has become practicable during recent years to supplement
empirical methods of weather forecasting, as developed in the nine-
teenth century on the basis of experience alone, with rational pro-
cedures based on an understanding of the physical processes involved ;
and as a result, weather forecasting has for some time been
developing along sound physical lines, though for a long time it
must continue to be a combination of physical reasoning with
methods based on accumulated practical experience with synoptic
charts.
Modern contributions to the difficult problem of weather fore-
casting are being actively studied and tested in the meteorological
services of the United States and other countries, and the Weather
Bureau is keeping informed on all important developments in this
field. During the fiscal year 1936 substantial progress was made in
developing air-mass analyses and applying them in forecasting.
In air-mass analysis attention is primarily directed to the great
streams of air that are present over a given region and are com-
posed of masses of air of different origin, properties, and motions,
separated from one another by more or less pronounced discontinui-
ties. The analysis of the synoptic map consists of the identification
and delimitation of the different air masses, the determination of
their motions and physical properties, and the relations of the
weather phenomena to the physical processes operating.
To develop an adequate and effective working procedure in this
analysis, to articulate it with the other work of the Weather Bureau,
and to amalgamate it with the accumulated knowledge and experi-
ence gained in the past, requires prolonged study and trial. The
work now being carried on is designed to develop, as quickly as pos-
sible, a satisfactory and workable technique. It has continually
been made of greater and greater assistance to the official forecasters,
who utilize it more and more in their work.
During January 1936 Sverre Petterssen, of the Norwegian Me-
teorological Service, conducted a series of lectures and conferences
at the central office of the Weather Bureau on the physical analysis
of weather maps (by the principles of air-mass analysis and also by
certain principles based on the kinematic theory of fluid motion) ,
and on weather forecasting. The analysis of maps and the making
of forecasts are two quite distinct things; and Dr. Petterssen's in-
vestigations have dealt particularly with the step from analysis to
forecast. Great benefit to the work of the Weather Bureau has
resulted.
In addition,_ a limited amount of research work on several prob-
lems involved in air-mass analysis and its practical applications has
been done — particularly a preliminary study of the physical phe-
THE YEAR IN AGRICULTURE 37
nomena leading to the development of the severe cold waves which
often enter the United States from Canada.
The past 7 years have been characterized by extreme heat and
widespread droughts in summer, wind and dust storms of unprec-
edented violence, damaging floods, and during 1935-36, extremely
low winter temperatures extending over wide areas of the country.
As a result of these abnormal weather conditions thousands of hu-
man lives have been lost, millions of dollars worth of property has
been destroyed, and the income of many farmers has been wiped
out or greatly reduced. The need for pursuing research studies look-
ing toward the making of long-range weather and crop predictions
is more apparent today than ever before. If there is one chance in
a hundred of discovering the causes of abnormal weather, the effort
is worth making, for agriculture, business, and the whole Nation
would gain thereby.
Projects Uptoer Bankhead- Jones Act
Under the Bankhead- Jones Research Act two lines of work have
been undertaken. One, in which the Weather Bureau, the Bureau
of Agricultural Economics, and meteorologists of Harvard University
and the Massachusetts Institute of Technology are cooperating, is a
survey and critical appraisal of methods now employed in attempts
at long-range weather forecasting by foreign countries and by pri-
vate individuals and agencies in tins country. This survey should
give a basis for research projects to be carried out during the fiscal
year 1937 and. thereafter. Certain statistical investigations also are
being carried on concerning planetary and lunar relationships with
terrestrial weather, and periodicities in weather and solar phenomena.
The other study is concerned with, the relationship between weather
and crop yields and involves the cooperation of several bureaus of
the Department, such as the Weather Bureau, the Bureau of Plant In-
dustry, and the Bureau of Agricultural Economics, and also the
assistance of a number of State agricultural experiment stations.
From these preliminary studies the Department expects to develop
more intensive research in crop-yield variations and weather factors
during 1937 and subsequent fiscal years.
Comprehensive soil, phenological, yield, and weather data have
been collected from experiment-station records in nine North Central
and two Middle Atlantic States and from records of the dry-] and
farming stations of the Bureau of Plant Industry. Statistical tech-
nique is being developed for determining the validity of combina-
tion or segregation of yield series of different rotations, soil treat-
ments, variety tests, etc., in order to form series that may be used
in measuring crop-yield responses to fluctuations in weather phe-
nomena. Most weather-crop research to date has been on an exten-
sive scale geographically; averages of crop yields and weather by
States and regions have been studied. It is believed the present,
more intensive approach will lead to greater knowledge of the basic
laws involved. A beginning has been made in the evaluation of work
previously done in this field.
Under the Bankhead-Jones Research Act a project has been set
up in the Bureau of Agricultural Economics in cooperation with
38 YEARBOOK, 1937
Harvard University to provide for the study of relationships be-
tween solar and terrestrial phenomena, especially relationships hav-
ing a bearing upon long-range weather forecasting. Equipment is
being designed, using the principles of telephotography, for mak-
ing daily observations of the sun's corona. Heretofore measure-
ments of this important indication of changes in solar activity
have been possible only at infrequent times of complete eclipse of
the sun.
In addition the Weather Bureau, with an allotment of funds from
the Works Progress Administration, has continued its investigations
begun with funds assigned it by the Civilian Works Administration.
This work consists in computing correlations between conditions in
the United States and precedent conditions in foreign countries. So
far correlations have been completed between temperatures by quar-
ters in 12 districts of the United States and pressure conditions at
60 foreign stations distributed throughout the world, both in the
Northern and Southern Hemispheres. The time intervals employed
were 3, 6, and 9 months. The survey of rainfall conditions in the
United States as compared with precedent pressure conditions at
the 60 foreign stations is rapidly nearing completion. It is planned
next to compute con-relations between foreign temperatures and
foreign rainfall with subsequent temperature and rainfall conditions
in the United States.
MEASURES FOR DROUGHT RELIEF
With other Government agencies both Federal and State, this De-
partment cooperated in measures for drought relief. It so modified
the soil-conservation program as to make allowance for conditions
beyond the control of the farmers ; issued supplementary provisions
to increase the production of feed and forage ; encouraged the plant-
ing of emergency forage and hay crops; and in general enabled
farmers in drought areas to take advantage of the income-insurance
features of the program. The Government's readiness to make pur-
chases of livestock from drought areas protected markets against
sharp declines. Loans for the purchase and storage of seed enabled
farmers to prepare for the next crop. An agency established at
Kansas City facilitated the movement of feed into drought-stricken
areas and also the movement of livestock from drought areas to
localities where surplus feed and pastures were available.
Under the surplus-removal clauses (sec. 32) of the amended Agri-
cultural Adjustment Act, quantities of food and feed became avail-
able for relief in drought States. Between June and September the
shipments included 1,171 carloads of foodstuffs for human consump-
tion and 375 carloads of millfeed for livestock. Some shipments of
this kind would have been made in any case ; but the drought emer-
gency necessitated a considerable increase in shipments to drought
areas. The Resettlement Administration made loans and grants to
farmers for the purchase of feed, seed, forage, and food ; the Works
Progress Administration provided employment to farmers in road
construction, in well digging, and in building small dams and res-
ervoirs. The Farm Credit Administration alleviated credit diffi-
culties, and the Federal Surplus Commodities Corporation carried
THE YEAR IN AGRICULTURE 39
out a small-grain seed-conservation program. Western and Middle
West carriers reduced freight rates on feed and livestock.
Beef-cattle numbers were more nearly in balance with feed sup-
plies and with market requirements than they had been during the
drought of 1934. Indications were that prices would be favorable
to producers in 1937. There was no need, as there had been in the
previous emergency, for the Government to buy several million head
of cattle. It purchased only enough to prevent sharp price declines,
and restricted the purchases to the classes and grades of cattle least
suitable for resale as stockers and feeders and least desirable for
breeding herds. It disturbed the commercial cattle trade as little as
possible and encouraged a movement back to the country for feeding
and breeding.
The A. A. A. began purchasing cattle in the drought area on Au-
gust 3, when market receipts above normal requirements caused a
decline of prices. It made limited open-market purchases at termi-
nal markets serving the drought territory. Up to September 4, how-
ever, it had purchased only 2,964 head. By that time fall rains in
parts of the drought territory had encouraged farmers to retain cat-
tle and had increased the demand for feeder stock. Funds available
under section 32 of the amended Agricultural Adjustment Act pro-
vided the means for purchases of surplus livestock. The payments
to farmers and ranchers were purchase payments only; they did not
include additional benefit payments, as the cattle and sheep pur-
chases in 1934 had done. Meat resulting from the buying programs
went to the Federal Surplus Commodities Corporation for relief
distribution. „
Seed-Grain Situation
There was a shortage of small grains suitable for seeding in the
drought territory. The seed-grain purchase program helped to pre-
vent an acute deficiency and to obviate the planting of light and
undesirable seed in 1937. It provided for an advance of not more
than $10,000,000 to the Farmers' National Grain Corporation, a
farmers' cooperative, for the purchase of between 7,000,000 and
9,000,000 bushels of spring wheat, durum wheat, oats, barley, and
flax. Seed grain thus acquired will be sold to farmers at reasonable
prices before seeding time in 1937. Supervised by the Federal Sur-
plus Commodities Corporation, the seed-purchase program included
efforts to conserve and store desirable seed stocks.
It became evident in September that little corn suitable for seed
in the western and north-central part of the Corn Belt will be avail-
able for the year's crop. Keports from large sections of the western
Corn Belt indicated it would be necessary to get from 2,000,000 to
3,000,000 bushels from other localities outside the worst drought-
stricken sections. As a means of guarding against a shortage of
adaptable varieties, the Government offered two types of non-recourse
loans on farm-stored seed corn. One type made available a loan of
$1.75 a bushel on field-selected corn having proper germination and
storage qualities. The other offered a loan of $0.55 a bushel on good
Duality and properly stored crib corn, suitable for sorting at a later
ate. Each loan note gave the Government a purchase option
40 YEARBOOK, 1937
amounting to $3.50 per bushel on the field selected and $1.50 a bushel
on crib-selected corn, shelled and graded in the sack.
It proved difficult for the railroads to grant blanket reductions
in freight rates on shipments of feed and livestock. They feared
to incur some liability for discrimination, against which they had
been specially protected in 1934 by a provision in the Drought Belief
Appropriation Act. However, they made piecemeal concessions.
In the most seriously affected areas carriers quoted emergency rates
on hay amounting to two-thirds of the normal rates. On coarse
roughages they quoted 50 percent of the usual hay rates. On coarse
grains and feeds and on feed ingredients they accepted shipments
at two-thirds of the normal rates. These concessions enabled
farmers to obtain feed from distant points and helped to keep local
feed prices at more reasonable levels. On shipments of livestock to
surplus-feed and pasture areas the railroads made a rate of 85 per-
cent of the normal rate, with the privilege of returning the cattle
on a 15-percent basis.
Comparison With 1935 Feed Supply
The production of feed grains as estimated on September 1, 1936,
was approximately 42 percent below the average for the 5 years,
1928 to 1932. But the number of livestock on farms was slightly
less than during the 1928-32 period. In consequence, the production
of feed grains per grain-consuming animal unit was only about 38
percent below the 1928-32 level. In terms of feed-grain production
per animal unit, the output was about the same as that of 1934. The
1936 drought came later than that of 1934 and covered a smaller
portion of the range and pasture areas of the West. Early hay pro-
duction was not so seriously affected. Hay production per hay-
consuming animal was only about 14 percent below the 1928-32 aver-
age, as compared with 35 percent below in 1934. Because the 1934
drought became serious early in the season, Congress appropriated
$525,000,000 for drought-relief activities. This year's drought did.
not become serious over large areas until late in June. No special
appropriation for meeting it had been provided. Federal and State
agencies modified their programs, however, in such a way as to pro-
vide substantial assistance to farmers in the drought areas.
LONG-TERM POLICIES FOR DROUGHT AREAS
Looking toward the development of a long-term program cal-
culated to render future droughts less disastrous in the Great Plains
region, a committee appointed by Executive order visited the region,
conferred with farmers and public officials in the areas most seriously
affected, and drew up a series of recommendations. The committee
utilized the experience of numerous Federal and State agencies,
many of which had dealt for many years with the problems of the
semiarid lands. These agencies placed a mass of material at the
committee's disposal, and the conclusions reached were in large part
the result of studies and experiments begun long ago. In thus
bringing to a focus the best available knowledge on the subject the
committee accomplished a work of outstanding public importance
and laid a foundation for an effective remedial policy. The com-
THE YEAR IN AGRICULTURE 41
mittee's findings, in which I heartily concur, may usefully be sum-
marized in this report.
Analyzing the causes of the present disaster, the committee
assigned primary importance to the attempt which has been made
for several decades to impose on the Great Plains a system of agri-
culture not adapted to the region. Methods suited on the whole
only to a humid region Avere introduced into a semiarid region.
This was largely the outcome of a mistaken public policy. The
Federal homestead law, for example, kept land allotments low and
required that a portion of each allotment should be plowed. This
policy, the committee said, caused immeasurable harm. On the
western Plains it Avas both a stimulus to overcultivation and a
condemnation of the cultivators to poverty.
Efforts to cure the trouble by enlarging the allowable individual
holding did not work. In western North Dakota and Montana tracts
two or three times the size of those actually granted would have
been necessary to support farm families adequately. As the ranges
were enclosed, feed crops were grown by intensive cultivation and
the ranges were overstocked. Overcropping, overgrazing, and im-
proper farm methods generally made the soil loose and unstable, pro-
moted soil blowing and washing, lowered the ground-water level,
and rendered the whole area extremely vulnerable to periodic
droughts. The settlers themselves could not avoid these mistakes.
They lacked both the knowledge and the incentive to do so and were
the victims of a mistaken national policy.
Settlement of the western Plains began, the committee observes, at
the end of what appears to have been a 40-year dry period. It pro-
ceeded during a wet period which now seems to be terminated.
Droughts in the region during the latter part of the nineteenth cen-
tury and the early years of the twentieth century were brief and
infrequent. Farmers regarded them as exceptional and did not
change their farming methods. Weather records indicate, however,
that a long dry period preceded the settlement of the Great Plains
and that we may now be in the midst of another prolonged dry
period. This may have its wet years but may keep the average rain-
fall for a period below the long-time average.
It is impossible to make a confident forecast. But whether the
present drought condition be brief or prolonged, the problems of the
Great Plains region will remain essentially the same. Continued
farming and ranching by the existing methods will cause continued
trouble under any climatic conditions that are likely to prevail. The
problem is not the product of a single drought or even of a series
of bad years. It is the outgrowth of a mistaken policy pursued for
decades.
The Critical Area
The Great Plains comprise an area stretching from west central
Texas to the border of Canada. On the west the Kocky Mountains
are the border. On the east the region is irregularly delimited near
the one-hundredth meridian, where formerly the short-grass country
merged into the tall-grass or prairie country. In the critical area are
the Texas Panhandle, the Oklahoma Panhandle, northeastern New
138904°— 37 4
42 YEARBOOK, 1937
Mexico, and all the northern portion of the Plains. Annual rainfall
is low throughout the entire region. There are short, intense storms,
wide fluctuations of temperature, and strong prevailing winds.
Frost and snow make wind erosion a less serious danger in the north
than in the south ; but soil blowing and soil depletion occur through-
out the region, particularly in areas of excessive plowing.
Millions of acres of the natural cover, the buffalo grass and grama
grass, have been destroyed in the Great Plains and the soil made
loose by continued cultivation, decay of grass roots, and reduction
of the humus supply. This destructive process has been accelerated
since the World War. Eight States lying partly within the region
had 103,200,000 acres of harvested crops in 1929, as compared with
87,800,000 in 1919 and 12,200,000 in 1879. How wrong this plow-
up program was can be inferred from the records made under the
Homestead Act. Only 60 percent of the entries were perfected
prior to 1916. Since then only 45 percent of the entries have been
perfected.
The results of attempts at the intensive cultivation of the Great
Plains over a tremendous aggregate area have been bankruptcy, tax
delinquency, absentee ownership, and excessive tenancy. In 1935 the
percentage of tenant farmers in eight Great Plains States was 41.1,
as compared with 15.5 in 1880. Many farms have been abandoned.
Many residents moved out of the Great Plains between 1930 and 1935.
The "suitcase farmer", of whom there were too many, visited his
land only a few weeks each year for planting and harvesting. In
drought years he abandoned his crop. He never made permanent
farm improvements. Community services declined. The problem is
not simply one of short-term relief but of long-term readjustment
and reorganization.
Primarily, it is necessary to check overcropping and overgrazing,
so that both soil and water may be conserved, and this end cannot
be attained exclusively by individual action. Yet the committee's
proposals do not strike at the independence of the individual farmer.
On the contrary, the action recommended should restore an inde-
pendence that has largely been lost. New public policies, designed
to correct the existing mistaken policies, will stabilize the econ-
omy of the region and increase its power to maintain independent
farm families. The fundamental requirement is to bring farm-
ing and livestock-raising methods into conformity with the natural
conditions.
_ In many measures the Federal Government should take the initia-
tive, particularly in leadership and guidance. Federal participation
may be necessary also in the construction or financing of public
works. Past Federal policy encouraged the misuse of the Great
Plains. Present Federal policy should encourage the correct use.
In emphasizing this principle the committee states that there need
not be any conflict of jurisdiction between Federal agencies on the
one hand and State and local agencies on the other. It believes that
joint cooperative effort will prove workable, and more effective than
any other method. Needless to say, the action taken should be con-
tinuous over a long period, with Federal and State agencies under-
taking the functions they are best able to perform.
THE YEAR IN AGRICULTURE 43
Combination of Measures Necessauy
Efforts to develop a Great Plains economy capable of withstand-
ing recurrent drought will require various measures involving Fed-
eral, State, and local cooperation. The basic aim should be to arrest
excessive soil erosion and to conserve water. Public grants and
subsidies should be harmonized with a plan calculated ultimately to
do away with the need for such aids.
Soil and water conservation will require engineering, good agron-
omy, changes in tillage practices, financing, and public education.
On cultivated land it will be necessary to promote contour plowing,
listing, terracing, strip cropping, and other soil-conserving practices.
Dams may be of use in checking water erosion and in holding water
for use in dry periods. Reservoirs and wells should be developed.
Small irrigation systems for groups of families will be found useful.
In some areas large irrigation projects may be needed. Certain sub-
marginal lands should be permanently.withdrawn from farming.
Measures of this kind? however, can merely improve the conditions
and practices on individual farms. They cannot effect the basic
changes necessary in the whole land-use pattern. Therefore the com-
mittee recommended that public acquisition of lands should be
continued on the basis of selecting those areas less suited to cultiva-
tion and grazing. Extension of the grazing range could be brought
about in certain areas by bringing some arable farm land under
public ownership. Abandoned farms or tax-delinquent land could
sometimes be acquired. Land in some areas, it proposed, should be
leased or optioned, with a stipulation that the users shall carry on an
approved program of restoration to grass or forest.
Public land buying and regulated grazing, however, will not be
fully efficacious if private owners may still use their holdings in a
manner destructive to neighboring property as well as to their own.
Therefore the committee suggests that the possibility of restraining
wrong land uses should be explored within legal and constitutional
limits.
In some areas cooperative grazing districts are attempting to pre-
vent the overgrazing of their lands; and this policy the committee
warmly endorsed. Each thing done, it declared, should be part of a
coordinated project covering the entire region. As an aid to the
cooperative control of grazing, it suggested that public land buying
in some areas would help to block out desirable ranges. Such a
project could be set going without arbitrary action by any public
agency, and it could be carried out democratically by using existing
facilities for ascertaining local interests and wishes. The pooling of
scientific knowledge in a well-conceived educational campaign would
be indispensable.
Research should be undertaken to determine how many people the
region can properly support. With that determined, the problems
of migration and relocation would be simplified. While discourag-
ing aimless migration, the committee believes that in some areas a
regrouping of the population would be beneficial. It is impossible,
as yet, to determine whether or not the region can adequately sup-
port its present population. A shift from cropping to grazing might
reduce the population in some localities but at the same time increase
44 YEARBOOK, 1937
the real wealth of the region as a whole. Ultimately, the change
would provide additional income. The fundamental purpose is not to
depopulate the region, but to make it permanently habitable. Any
other aim would be a confession of failure. In the long run the
Great Plains will support more people on a higher standard of living
if its agriculture is regulated intelligently than it can possibly sup-
port if present tendencies run their course.
In some localities farm holdings should generally be larger than
those now prevailing. Such necessary increase in the size of farms
would require governmental assistance. State and county govern-
ments may expedite the consolidation of small units by making avail-
able to grazing and other cooperative agencies certain tax-delinquent
lands, which will not again be cultivated by their nominal owners.
The aim should be to develop holdings large enough to support farm
families in independence and comfort.
It is proposed that the possibilities of rural zoning be explained
as a means of preventing the sporadic settlement and breaking up of
lands better adapted to range use than to arable farming.
The committee recommends the use of public credit to enable com-
petent tenants to purchase and operate their own farms. Tenancy,
it says, promotes soil mining and does not suit the Great Plains.
Also, the committee recommends the study of crop insurance and of
ways and means to promote the transfer of certain croplands to
grass farming. It urges public guidance in resettlement, and investi-
gations to determine what new Federal legislation, if any, will be
necessary. Essentially the committee finds that, while present
methods in the Great Plains do not promise success, methods suited
to the region can be developed through Federal, State, and local
cooperation. _
Crop Insurance
In the farmer's life luck and chance are important factors. Each
crop planted is a speculative venture. Unfavorable weather condi-
tions, floods, insects, or disease may cause a partial or a complete fail-
ure of his crop. Studies of total farm income for all farmers do not
tell the whole truth. Increases in prices in years of low production
enhance the income of farmers who have a good crop, but benefit very
little those whose crop fails. The distress due to widespread crop
failure and the resulting necessary expense for relief suggest the need
of some form of crop insurance.
The programs of the Agricultural Adjustment Administration con-
tained a measure of crop insurance. The benefit payments were the
only income of many farmers after the drought of 1934 had destroyed
their crops. Undoubtedly the soil-conservation payments of 1936 will
likewise serve as crop insurance in drought areas. Crop insurance
resulted as a byproduct of the adjustment program in connection with
the administration of the Bankhead Cotton Control Act. In 1934
many farmers in the western part of the Cotton Belt produced less
cotton than their allotment of tax-exemption certificates covered.
Through the operations of a pool set up to make transfers, they were
able to sell their surplus certificates to farmers elsewhere who had pro-
duced cotton in excess of their allotments. Sale of their certificates
THE YEAR IN AGRICULTURE 45
enabled farmers who had suffered a partial or complete crop failure
to recoup part of their losses.
The principle of crop insurance merits a prominent place in any
broad plan for a national farm policy. Insurance viewed from the
standpoint of the individual appears primarily as a contract for the
indemnification of losses. Viewed from the standpoint of the whole
group, however, it appears rather as an averaging of losses. The
insured individual pays the average loss instead of taking the chances
of suffering a larger loss. Insurance is a social device by which "the
loss lighteth lightly upon the many rather than heavily on tne few."
Crop insurance is a means by which systematic contributions by
farmers, made in proportion to the risk to their crops, create a reserve
out of which agriculture can finance its own relief from crop disaster.
It does not prevent disaster, but it does provide that the full weight
shall not fall on a few.
Crop insurance differs in some respects from other types of insur-
ance. It insures against the loss, not of an existing value, but of a
prospective value. In fire insurazice loss can readily be measured,
because the value of the property is known or can be estimated. But
if a crop fails, what is the loss? Is it the difference between the actual
production and a bumper crop ; between the actual production and an
average crop; or between the actual production and the investment
in the crop ?
Many have questioned whether it is sound policy to insure prospec-
tive profits and have advocated insuring only the investment in the
crop. But the investment in the crop is difficult to determine. Much
of it represents the farmer's labor and other items that must be
evaluated. Little of it represents a cash outlay that can be measured
accurately. It seems better to insure only a certain proportion of the
average yield. That is much simpler. If only a reasonable per-
centage of the average yield is insured, the plan does not include the
insurance of prospective profits.
Requirements of Crop Insurance
Crop insurance should have a large element of saving. That is, it
should involve not merely a horizontal averaging of losses for each
year but also a vertical averaging of losses over a period of years.
Losses in certain years may be so widespread that accumulations from
more successful years are necessary to help carry the burden. This is
very important. Hence the rates for crop insurance should be based
on the average losses over a long period or over a shorter period that
was worse than the average for most short periods of years. The
successful operation of a plan for a few average years does not prove
that it could successfully meet widespread disaster for several years.
Substantial reserves should be built up in good years.
All-risk crop insurance is not available to the farmer today. Insur-
ance companies have made several attempts to insure the crop of
wheat and other grains. In 1917 such an attempt in the spring-wheat
area failed partly because of drought and partly because insurance
was written after it became apparent that there would be a short crop.
In 1920 another attempt failed largely because it included price insur-
ance, and prices fell off sharply. Still another attempt in 1931 and
46 YEARBOOK, 1937
1932 failed because of a sharp drop in prices. But hail insurance, a
specialized type, has proved successful.
Insurance has quite frequently been written on fruit and vegetable
crops, particularly against frost and freeze hazards. Such insurance
has sometimes been taken out only to protect the creditor. There is
little being written today, most or the companies having withdrawn
from the field. The experience was not always successful. The
hazards were so great that a single company could not afford to carry
the risk and reinsurance on such business was difficult to arrange.
The large uncertain hazard for a single company necessitated high
rates.
If crop insurance is to be made generally available to the farmer,
probably the Government must assist. The Government is better
able than private enterprise to carry out the venture on a scale large
enough to reduce the impact of heavy losses in certain areas. Insur-
ance, where extensive public protection is at stake, is not new for the
Federal Government. We have insurance of bank deposits, insurance
of loans for financing the construction and repair of houses, and life
insurance for veterans. Also, we have unemployment insurance and
a system akin to insurance for providing old-age annuities. Crop
insurance would provide the farmer with a measure of social security
comparable in some ways to the unemployment insurance and old-
age retirement from which he is excluded under the Social Security
Act.
Crop insurance, to be successful, should have an actuarial basis.
There is little crop-insurance experience to study and reliance must
be placed on the loss experience of farmers in general, with proper
allowances for an adverse selection of risks. This Department is
studying the problem with data for individual farms gathered inci-
dent to the adjustment programs of the Agricultural Adjustment
Administration. These data cover a 5- to 6-year period which in-
cluded several drought years. They are supplemented by estimated
average-yield data for a long period. The estimates of cost derived
therefrom should be conservative. The study emphasizes a type of
insurance in which the coverage would be a certain fraction of the
yield on the insured farm. Such a plan would not put a premium on
the farming of poor land or on poor farming practices.
Differences among areas and counties are being studied, because
rates would have to vary. Kates based on average costs over a wide
area would attract only those who were favored by these rates. They
would bring into the insurance group only farmers with risks greater
than the average. In that event the losses would exceed the premiums
collected. As far as possible, premium rates and insurance coverage
should be so adjusted that each type of farmer and each type of farm
would bear its own cost. Over a period sufficiently long, each farm
should bear its own cost.
Crop insurance must not benefit the shiftless at the expense of the
thrifty, and the poor land at the expense of the good. In large
measure the insurance coverage and the premium rate should be
based on the experience of the individual farm. The insurance cov-
erage for an individual farm should probably be a given percentage
of the average yield for that farm. The premium rate should prob-
THE YEAR IN AGRICULTURE 47
ably, in a measure, be based on the average crop losses of that farm.
The data acquired for individual farms in the agricultural-adjust-
ment program might provide a starting point.
Principle of the Ever-Normal Granary
Crop insurance would be an attempt to solve the problem of short
crops. But bumper crops have not been an unmitigated blessing to
the farmer. Frequently a large crop sells for less than a medium
or a small crop. Both problems arise from wide variations in pro-
duction, the one being the counterpart of the other. Perhaps a single
solution could be worked out for both problems. Some system that
would tend to level off the amount that individual farmers could and
would place on the market in various years would tend to solve both
problems.
In line with this thought the Department, in its studies of the
costs of crop insurance, has given some consideration to the possi-
bilities of the option oi paying for the insurance "in kind", out of
the production of years oi surplus. This should make the burden of
the insurance premiums lighter and easier to bear. In the sample
studies that have been made the surplus production was calculated
for each farm, the surplus production per acre being considered as
the excess of the actual yield over the average yield. Only a fraction
of that surplus would be needed to pay for insuring the yields up to
75 percent of the average yield for each insured farm. In fact, for the
G-year period 1930-35 only from one-third to two-thirds of the surplus
production would bo necessary to meet the net cost of such insurance.
The plan, involving payments in kind and payment of premiums
only in years of surplus, would really become the ever-normal granary
plan with crop-insurance requirements serving as an automatic regu-
lator. In years of surplus a part of the crop would be drawn off the
market and put into storage — the amount so drawn off being regu-
lated by the predetermined insurance rates based on actuarial calcu-
lations. In years of crop failures the stored commodities would be
released, the amount being automatically determined by the amount
of indemnities necessary as defined by the insurance contracts. Since
the plan would operate automatically, with the commodities being
released from storage only in case of crop failure, the commodities in
storage would not be a potential supply on the market tending to
depress the price.
During surplus years the removal of the excess commodities from
the market would tend to support the price. The part of the crop
not used for insurance premiums would still be more than the farm-
er's average production, and with a supported price the income from
the crop should be reduced but little, if at all. The release of com-
modities from storage in years of crop failure would tend to hold
down the price, but farmers without a crop do not benefit from high
prices. Under this plan the farmers who lost their crop would be
indemnified, while the farmers who produced a crop would get at
least average prices.
Furthermore, as a form of price stabilization this plan would re-
quire no funds to buy up the commodity. The participating farmers
would provide the capital in the form of premium payment in kind.
48 YEARBOOK, 1937
Any Plan Should Be Optional
While the above plan for crop insurance has many excellent fea-
tures, it would present many problems. The Department is com-
mitted to no single plan. It is interested in all possible angles of the
problem and in various possible plans. Certain plans may be suited
to some areas, and other plans to other areas. Any plan adopted
should be voluntary and optional with the farmer.
Crop insurance is needed most in the single-crop areas. In regions
of diversified farming the loss of a single crop is less calamitous.
But though diversification is a form of self-insurance, it does not
adequately offset losses from extensive droughts, floods, and infesta-
tions. Another form of self-insurance is the accumulation of re-
serves of feed and supplies and the accumulation of savings in some
form of investment. But this method, too, needs often to be sup-
plemented.
Farmers have learned much in recent years about handling their
local farm problems. Their experience under the A. A. A. should
provide a base for the local administration of an insurance pro-
gram. But if crop insurance is tried, it should be as an experiment
and should be confined at first to one or two crops — wheat and pos-
sibly corn or cotton. It should be limited in the beginning to areas
where there is a real need and a real demand. It should not be con-
sidered a complete protective program in itself, but should be part
of a larger unified program involving soil conservation, retirement
from farm uses of land unsuited to agriculture, judicious commodity
loans, and the ever-normal granary.
COTTON
In some respects the cotton situation is better now than it has been
for several years. This year's crop of 12,400,000 bales (November
estimate) is larger than that of 1934 to 1935, but the carry-over of
American cotton is the smallest since 1930, and the world supply of
American cotton is the smallest in 12 years. There is no shortage of
American cotton. On the contrary the supply is more than ample,
but in comparison with the situation in recent years the present sup-
ply-and-demand relationship is not so unfavorable to the producer.
In fact, returns to domestic growers promise to exceed those received
for any crop since 1929.
Since August 1932 the world carry-over of American cotton has
been reduced from 13,000,000 to 7,000,000 bales. Though still some-
what larger than an average carry-over, this quantity is 2,000,000
bales below the carry-over in August 1935 and is the smallest in 6
years. The total world supply of American cotton this season will
be about *4 million bales less than in the previous season, despite
the increase in the 1936 crop.
Income to farmers for cotton marketed during the present crop
year will probably be the largest since 1929-30, though about 30 per-
cent below the average for the period 1919 to 1929. Among the
causes of the improvement are of course recovery of business at
home and abroad, changes in the supply position, and the reciprocal
trade agreements program which the Government has insti-
tuted. This program benefits cotton exporters by enabling foreign
THE YEAR IN AGRICULTURE 49
buyers to get dollar exchange. Part of the advance which has taken
place in the price of cotton since 1933 may be attributed to dollar
revaluation. Production control has been an important factor. The
revaluation by itself would probably have encouraged farmers to
increase their output and would have tended to counteract the influ-
ence of the monetary policy. The improvement in the cotton situa-
tion is the outgrowth of numerous factors the separate influence of
which cannot be accurately measured.
Certain unfavorable aspects of the situation should be noticed.
World consumption of cotton in the 1935-36 season was about
27,700,000 bales, the largest consumption on record. American cotton
accounted for 12,500,000 bales, as compared with 11,300,000 bales the
previous season. Though American cotton represented a slightly
larger proportion of the consumption in 1935-36 than it did in 1934-35,
it was materially below the average for the decade ended 1933. Mill
consumption of foreign cotton, on the other hand, increased to a new
high level and was above the 10-year average and above the consump-
tion of American.
Numerous factors contributed to this shift in the relative consump-
tion of American and foreign cotton, some of them of long standing.
The production of cotton in other countries increased rapidly after the
World War, side by side with an increase in our own production.
Meantime trade restrictions throughout the world, among which our
own tariff policy exercised a large influence, tended to handicap our
cotton-export trade. Foreign countries turned as much as possible to
foreign cottons, particularly when they could offer industrial com-
modities in exchange. They wanted to buy where they could sell,
and the American tariff policy made it difficult for them to do so in
the United States.
Obstacles to Cotton-Export Trade
When cotton prices and income fell to the low levels of 1932, it was
evident that something had to be done to help American growers.
With the aid of the Federal Government domestic producers under-
took to readjust their output. The ensuing price recovery inevitably
benefited foreign as well as American cotton growers, and the trend
toward relatively increased production of foreign growths, which had
long been in evidence, continued, although perhaps not to the extent
implied in the trade press.
Obstacles quite independent of our production policy stand in the
way of increased foreign consumption of American cotton: (1) The
difficulty foreign consumers still have in getting dollar exchange, and
so long as we bar out foreign goods this difficulty cannot greatly
diminish. (2) Other countries are forging ahead in cotton production.
(3) The competition of other fibers is growing. These obstacles, how-
ever, can be surmounted. Recent trends in our tariff policy are steps
in the right direction. Our advantages in cotton growing are sub-
stantial, and the world demand for cotton should continue to increase.
When he can do so without losing money, the American grower will
respond. The Department is engaged in an extended cotton-
breeding program which should play its part eventually in making
the American cotton grower the most efficient in the world.
50 YEARBOOK, 1937
WHEAT
Despite the effects of the drought the total supply of -wheat in
the' United States for the 1936-37 season is large enough for the
usual domestic requirements. Supplies of hard red spring wheat and
durum wheat are short, however, and imports of these types will
continue. The drought reached its greatest intensity in the hard
red spring and durum wheat areas. The winter-wheat crop was
larger than that of 1935 and of good quality. Probably the spring-
wheat mills will use a larger percentage of hard red winter wheat
and Pacific Northwest wheat this year than they did last. More
than the usual quantity of soft red winter wheat will probably be
used in bread flour. It is expected therefore that the imports
of milling wheat in 1936-37 will not exceed the 26,000.000 bushels
imported in 1935-36.
The Pacific Northwest, the principal white-wheat region, again
produced a surplus. In 1933-34 the disposal of its surplus was
financed out of processing-tax funds. In 1935-36 exporters in the
Pacific Northwest were indemnified for losses sustained on exports
to the Philippine Islands, funds for which were made available from
tariff revenues under section 32 of the amended Agricultural Adjust-
ment Act. In this same year, as well as in 1936, considerable
amounts of white wheat from the Pacific Northwest moved east of
the Rockies, some of it going into relief channels. Ordinarily, how-
ever, wheat from the Pacific Northwest cannot compete east of the
Rockies with Great Plains wheat, which normally constitutes the
bulk of our supply of bread wheats. In years of average United
States production the Pacific Northwest must seek a market abroad.
Since 1933 wheat prices in the United States have been high in
relation to the world market price. They have ranged from 20 to
30 cents a bushel higher than they would probably have done had our
production been normal. Average or above-average yields in this
country next year would give an export surplus and cause an adjust-
ment of the domestic price toward an export basis. On an acreage
equal to that seeded for the 1936 crop, yields one-fourth below the
average would provide enough wheat for the usual domestic utiliza-
tion.
Our wheat farmers continue to expand their acreage. The area
seeded for the 1936 crop was 74,500,000 acres, the largest on record
with the exception of that seeded in 1919. In 1935 growers who had
signed the A. A. A. wheat-adjustment contract had the right to
plant 95 percent of their base acreage. But many had seeded winter
wheat in the fall of 1935, before the contract Avas offered to them,
and there was a tendency for farmers to plant larger acreages. In
addition, nonsigners increased their seedings. Large acreage does
not always mean large production. In years of normal growing
weather, however, the existing wheat acreage in the United States
will produce large export surpluses, for which satisfactory outlets
do not now exist.
It is better to have a balanced acreage. With a balanced acreage
less land shows a loss in drought years, and less wheat has to be
sold below cost in years of normal crops. In 1936 the soil-conserva-
tion program provided payments to wheat growers for the diversion
THE YEAR IN AGRICULTURE 51
of land from soil-depleting to soil-conserving crops. However, the
list of soil-depleting crops included many crops besides wheat, and
participating growers did not have to make any adjustment in their
wheat acreage if they were in a position to divert other land from
soil-depleting to soil-conserving uses.
Cash farm income from wheat in 1936 may be between $425,000,000
and $465,000,000, exclusive of payments to wheat farmers under the
agricultural conservation program. The corresponding figure for
1985 was $353,284,000, excluding the $115,368,000 in the A. A. A.
adjustment payments. Cash farm income from wheat in 1932 was
only $195,860,000. Needless to say, the income from wheat this year
will be very unequally distributed as a result of the drought. Growers
in the States worst affected will receive comparatively little, while
growers in the States not affected will make large returns. This
rough estimate of wheat income rests partly on the expectation that
world wheat prices in 1936-37 will be materially higher than they
were in 1935-36. Several important wheat countries, as well as the
United States, have below-average production this year.
Distribution Within the United States
Market outlets will have more effect on the distribution of wheat
within the United States in the future than they have exercised here-
tofore. In the 1920's there was a good demand for wheat in the
markets of the world. All that was grown was sold at prices fairly
remunerative. That is no longer the case. Formerly this country
exported principally hard red winter, durum, and soft white wheats;
there was a sufficient market at home for all or nearly all our hard
red spring and soft red wheats. Hereafter the absence of an
adequate foreign demand may create new problems of internal
convpetition.
Our high-quality hard wheat is produced in the Great Plains under
changing weather conditions and with widely fluctuating yields.
Other regions are not adapted to producing it. Varieties of hard red
spring and hard red winter wheat are grown to some extent in the.
Pacific Northwest and in the Corn Belt, but the product is less desir-
able for milling than the wheat grown in the western Great Plains.
Farmers in the soft red winter wheat region may shift from wheat to
other crops, as the prices of the latter crops rise in relation to wheat
prices. In the Pacific Northwest, however, the farmers have fewer
alternative crops to which they may turn, and this region will continue
to be a specialized wheat region. This area will continue to have a
considerable surplus of the soft wheats for export.
In the Great Plains the bread wheats will be the mainstay. Part of
the area plowed during the 1920's is better suited to ranching. Else-
where, however, the Great Plains will continue to produce wheat,
despite the prevailing climatic and other hazards, because the wheat
grown there has exceptional value for milling and because wheat in
large areas of the Great Plains had a marked comparative advantage
over other crops. Measures should be taken to stabilize the income
from wheat in this region so that the Nation may have a reasonably
dependable supply of bread wheat.
52 YEARBOOK, 1937
LIVESTOCK AND FEEDS
Recovery in livestock production was under way last year follow-
ing the 1934 drought, but this year's drought checked it. On Janu-
ary 1, 1936, the number of grain-consuming animal units on farms
was somewhat greater than it had been a year earlier, when it was
the lowest since early in the present century. On the other hand,
the number of hay-consuming animal units on farms was slightly
lower than a year ago, though above the 10-year (1925-34) average.
In January 1937 the number of both grain- and hay-consuming
animal units on farms may be as low as, or even lower than it was,
in January 1935. There was relatively heavy marketing of cattle
and hogs in the fall of 1936, and close culling of dairy herds and
poultry flocks. Moreover, the fall pig crop was smaller than that
of 1935.
Total feed-grain production in 1936 Avas larger than that of 1934.
There was a larger supply of hay and roughage. In consequence
the feed situation following the 1936 drought will be easier than
was that following the 1934 drought. Farmers will be better able
to winter their cattle, sheep, and work stock. But supplies of pork
and the better grades of beef will be reduced next year. They may
be almost as small as in 1935.
In 1936, for the third consecutive year, the demand for meats
improved. Though lower than in the 5-year period prior to 1931, it
was about equal in the first half of 1936 to what it was in the first
half of 1931. Consumers spent for meat in this period about 12
percent more than in the corresponding period of 1935. They spent
about 50 percent more than in the first half of 1933. The improve-
ment, of course, reflected general economic recovery. There was a
marked increase in both the total live and dressed weights of animals
slaughtered under Federal inspection; the second half of the year
will probably record a further increase. Total slaughter for the year
will be much larger than it was in 1935, though less than the average
for the 5-year period 1930-34. In 1937, however, both the number
and weight of the animals slaughtered will decrease. It is not prob-
able that total yearly slaughter will again be equal to the average
of 1930-34 before 1940. The feed situation will affect the trend of
hog numbers more than the trend of any other species of livestock.
Indications on September 1 were that the 1936 corn crop would
be slightly smaller than that in 1934 and the smallest in 55 years.
On the other hand, the production of oats, barley, and grain sor-
ghums was large enough to give a combined production of feed grains
of approximately 58,000,000 tons, as compared with 54,000,000 tons
in 1934 and 93,000,000 tons in 1935. Corn prices will be relatively
higher during most of 1937, and hog production will be sharply
curtailed. Though the number of hogs available for slaughter in
the 1936-37 marketing year will be larger than in 1935-36, hog pro-
duction for the calendar year 1937 will be smaller than in 1936. Hog
prices for the marketing year beginning October 1 will probably
average about the same as they did in 1935-36.
Despite the drought, the income to corn and hog producers was
materially larger than that of 3 years ago. During the winter of
1932-33 the farm price of hogs fell below $3 per 100 pounds, the
THE YEAR IN AGRICULTURE 53
lowest level in more than 50 years. Income from the sale of hogs in
1932 amounted to only about $440,000,000, as compared with an in-
come of about a billion dollars for a number of years prior to 1930.
In 1936 the income from the sale of hogs was about $840,000,000, and
the farm price averaged $8.80 per 100 pounds. This sharp increase
in prices and income from the depression level in 1932 occurred
despite the absence of any material improvement in foreign demand
for hog products. The foreign market for United States hog prod-
ucts retains only a fraction of its former proportions. Import re-
strictions in foreign countries and a marked revival in European
hog production, which began effectively to curtail United States
exports of hog products a number of years prior to 1932, continue to
be the principal causes of greatly reduced exports. Exports of pork
and lard fell from about 2,000,000,000 pounds in the early post-war
years, to a little more than one-third as much in 1932, and since have
remained at approximately that level.
Uneven Distribution of Corn-Hog Income
Although the income of farmers in the Corn Belt States was much
greater in 1936 than in recent years, its distribution was very abnor-
mal. In the States hardest hit by drought, such as South Dakota,
Nebraska, and Missouri, the supply of corn, hogs, and other farm
products for sale was very small, and even though prices were very
favorable the income of farmers was small as compared with the
income in the other Corn Belt States, where the effects of the drought
were not nearly so great. The uneven effects of the drought were
reflected in uneven distribution of farm income. In such States as
Nebraska and South Dakota, where farmers had not recovered from
the effects of the 1934 drought and where very little was obtained
from the sale of cash crops in 1936, the payments received for par-
ticipation in the 1936 agricultural-conservation program constituted
a substantial proportion of their total income for the year. As was
the case in 1934, payments for participation in the agricultural pro-
gram received by farmers in the drought areas were in the nature
of partial insurance against reduction in incomes resulting from
drought. _
Cattle
The general cattle situation was less influenced by drought in 1936
than in 1934. In parts of the northern Great Plains, however, heavy
liquidation of cattle was necessary. Beef cattle numbers at the be-
ginning of 1937 will probably be smaller than they were at the
beginning of 1936, though still above the average for the 10 years
1925-34. In January 1936 the total number of beef cattle, including
calves on farms, was approximately 32,300,000 head, as compared
with 36,100,000 head in 1934, when beef -cattle production was Hear-
ing a peak in the typical production cycle. Because of the reduced
level of hog supplies, in competition for the consumers' meat dollar,
the cattle industry is now in a rather favorable position, and for
the next few years the trend in cattle numbers will probably be
upward. In the first half of 1936 the average price paid by packers
for all cattle slaughtered under Federal inspection was $6.60 per
100 pounds, or slightly lower than that in the first half of 1935.
54 YEARBOOK, 1937
Sheep
Sheep and lamb producers fared comparatively well during the
last months of 1935 and most of 1936. Prices were above the levels
of recent years, though slaughter was relatively high. Sheep and
lamb production in 1936 was less affected by drought than in 1934.
The feed position is better for sheep at present than for hogs and
cattle, though in the Corn Belt many lamb-feeding areas have short
feed supplies.
The 1936 lamb crop was about 9 percent larger than that of 1935
and only slightly smaller than the record lamb crop of 1931. Fur-
ther expansion in the western sheep industry may be checked, how-
ever, by grazing-control measures instituted for the public domain
in western areas under the Taylor Act.
The production of shorn wool in 1936 was slightly smaller than
in 1935 and total supplies of wool on hand in this country at the
end of June were smaller than a year earlier. Wool prices in 1936
rose to the highest levels since 1929. Relatively high wool consump-
tion in Europe and a relatively low foreign wool supply strengthened
both foreign and domestic prices.
In the United States, however, the consumption of wool during
the first 7 months of 1936 was somewhat below that of the first half
of 1935, though above the corresponding monthly average for the last
10yearS- DAIRYING
Increased business activity and fuller employment caused an im-
provement in the demand for dairy products, while the drought cur-
tailed production. Prices for fluid milk rose and also prices for
manufactured dairy products. Butter prices were 100 percent above
the low point of the depression. Consumption of fluid milk and
cream, which declined in the early years of the depression, turned
upward in 1935 and continued upward in 1936. Markets that had
been burdened with surpluses faced temporary shortages. The con-
sumption of ice cream, and also of evaporated milk and cheese,
increased. With prospects good for further improvement in business
activity and employment, the dairy industry expected continued im-
provement in the demand for its products.
It seems probable that the drought, like that of 1934, will have
proportionately less net effect on dairy production than on the out-
put of other livestock products. In 1934-35 total milk production
per capita was only about 5 percent below the peak of 1931. Dairy
production in 1936-37 will probably be only from 5 to 7 percent less
than it would have been had the weather of 1936 been normal. How-
ever, the effects of the drought will be felt in 1937-38 in a reduction
in the number of cows on farms and in the number of heifers raised.
It is expected that the number on farms will decline in 1937 to a
relatively low level, owing to the heavy reduction caused by the
drought in the supply of feed.
Between January 1, 1927, and January 1, 1934, the number of
milk cows on farms increased 21 percent. This was much more than
the proportionate increase in the human population. In fact, in 1934
the number of cows per capita was the highest in 35 years. From
this point the drought of 1934 caused a decline, which continued in
THE YEAR IN AGRICULTURE 55
1935. By January 1, 1936, the number of milk cows per capita was
about equal to the average for the 30-year period 1900-1929.
The trade agreement with Canada that went in effect on January
1, 1936, contains provisions affecting the dairy industry. It provides
for a reduction of the import duty on cream from 56.6 cents a gal-
lon to 35 cents a gallon on not more than 1,500,000 gallons annually,
and also for a reduction in the duty on Cheddar cheese in original
loaves from 7 cents a pound, with a minimum of 35 percent ad
valorem, to 5 cents a pound, with a minimum of 25 percent ad
valorem. However, the reduced rate on cream is 5 cents a gallon
higher than the rate established by Presidential proclamation effec-
tive June 13, 1929 ; it is the highest rate on cream the United States
has ever had, with the exception of the rate established in the Tariff
Act of 1930. The reduction in the rate on Cheddar cheese brings it
down to the level that was in effect from September 1922 to June
1930.
In the first 6 months of the agreement the importation of cream
amounted to only 6,233 gallons. The total imports of cheese
amounted to 24,400,000 pounds — about the same as the relatively low
imports of the first half of 1935. Canada contributed about a sixth
of the total. In judging the effects of the reduced tariff rate on
cheese it should be remembered that less than 6 percent of the milk
produced in the United States goes into the production of cheese and
also that our imports of Cheddar cheese are a small proportion of
our total cheese production. The reductions in the tariff rates on
cream and cheese will have little or no effect on the level of dairy
pnCeS- TOBACCO
The 1936 tobacco crop, oil the basis of September 1 indications, was
the smallest since 1921 with the exception of the crops of 1932
and 1934. It amounted to 1,142,900,000 pounds, or 11.9 percent below
the production of 1935 and 16.2 percent below the average for the
7-year period, 1923-29. Drought conditions were mainly responsi-
ble for the reduction. In many tobacco areas the acreage planted
exceeded that of 1935. Only the cigar binder, the cigar wrapper,
and the Georgia-Florida flue-cured types showed an increase in
production. The production of all other types was much below that
of last year, and the quality in many of the drought areas was
impaired.
However, the stocks of domestic tobacco (farm-sales weight) held
by dealers and manufacturers, though 1.5 percent below those of
1935-36, were still 24.6 percent above the 7-year average, 1923-24
to 1929-30. The available supply is estimated at more than 200
million pounds above normal requirements for domestic consumption
and exports and for carry-over at the end of the year. The consump-
tion of nearly all tobacco products increased in 1936. In the first
7 months of the year cigarette consumption reached an all-time record
for that period. Indications are that the increase will continue.
Tobacco consumption per capita does not seem to be much affected
by changes in price, but it increases with business recovery and em-
ployment. Our tobacco exports increased. Flue-cured tobacco, the
predominant export type, represents about 70 percent of the total
56 YEARBOOK, 1937
exports; and the exports of flue-cured tobacco in the last fiscal year
were 32 percent above those of the preceding fiscal year, though 2.3
percent below those of 1933-34. Exports of Maryland tobacco
increased in 1936, while exports of other types declined.
Should the weighted average price for all types of tobacco
not fall below the August prices for the Georgia and Florida flue-
cured type and for the South Carolina flue-cured, the income to
farmers from the sale of leaf would be about equal to what it
was in 1935. FRmTS AND VEGETABLES
Fruit and vegetable production, according to the September esti-
mate, was about 11 percent less than in 1935, 9 percent less than in
1934, and about 6 percent below the average for the period 1928-32.
Truck crops decreased 13 percent, all fruits 9 percent, potatoes 20 per-
cent, and sweetpotatoes 19 percent. On the other hand, truck crops
for fresh market shipment were about 5 percent larger than in 1935.
Reduced plantings and the drought were the chief causes of the drop
in the production of truck crops for canning, of potatoes, and of
sweetpotatoes. Fruit crops suffered comparatively little from the
drought, but a severe late spring frost damaged apples, peaches,
cherries, and grapes. Favorable growing conditions later failed to
offset the damage, though citrus production was larger than in the
previous year.
Acreage planted to all truck crops for canning was about 4 percent
less than in 1935, but slightly larger than the harvested acreage in
1935 or in any previous year. Abandonment was substantial, owing
to the drought. Drought and heat combined reduced the yields, which
for all canning crops were about 10 percent below those of the pre-
vious year, and, in fact, were the lowest on record. Drought damage
was severe to sweet corn, snap beans, and green peas. The total sup-
ply of canned vegetables will be about 10 percent below the figure for
1935, but 19 percent above 1934. Production of vegetables for fresh
market shipment was higher than in 1935 owing to an increase in the
acreage. Yields were generally about the same, though dry weather
injured late cabbage. On the whole, the supply of fresh vegetables
was ample. Income to the growers, moreover, was higher than for
several years.
Potato production was estimated at only 312,000,000 bushels, as com-
pared with 388,000.000 bushels in 1935. The acreage, however, was
10 percent less, and drought damage was severe except in the far
West. For the country as a whole the indicated yield was only 97
bushels per acre, as compared with 109.2 bushels in 1935 and a 10-year
(1923-32) average of 112.7 bushels. Sweetpotato production, though
small in comparison with that of 1935, was above the 5-year (1928-32)
average.
In fruit production the 9-percent decline was largely in apples,
peaches, cherries, and grapes. The apple crop was 35 percent less
than in 1935 and was the smallest since 1921. Production of pears,
apricots, fresh plums, prunes, strawberries, cranberries, and citrus
was larger than in 1935. Citrus production may be one-sixth larger
than last year, while production of all fruits combined, except apples
and citrus, may be 12 percent smaller.
THE YEAR IN AGRICULTURE 57
POULTRY
With poultry flocks not fully recovered from the reductions caused
by the 1934 drought, the drought of 1936 is causing reductions again.
However, hatchings increased greatly last spring. There will prob-
ably be as many laying birds in farm flocks at the beginning of 1937
as there were a year before.
One important effect of the drought will be observed in the relation
of egg prices to feed prices. When feed prices rise more than egg
prices, sales of laying birds tend to be greater, production per bird
declines, and in the spring some reduction in hatching occurs. The
hatch of 1935 was reduced following the drought of 1934 because of
an unfavorable relationship between feed prices and egg prices.
Hatchings in 193Y may decline similarly.
On the whole, prices of eggs and poultry in the first part of 1936
have been favorable to the producer. Poultry prices, however, are
now declining. After the drought liquidation ceases they may re-
sume the upward trend of the last 3 years. Egg prices in early
1937, if they follow the course set after the drought of 1934, may
continue the present rising tendency.
AGRICULTURAL CREDIT
Farm-credit conditions have improved materially during the last
year or so, largely as a result of improvement in farm incomes and
a large amount of refinancing for long terms at low rates of interest.
In 1935 the demand for farm-mortgage loans declined sharply but
remained more nearly steady in the first half of 1936. Private lend-
ers began to return to the farm-loan field; and borrowers had the
further advantage of continued low interest rates.
The character of the 1936 mortgage financing, moreover? was very
different from that for the last 3 or 4 years. Loan applications to
an increasing degree were from farmers who were in no particular
emergency. An increasing number of the applications received by
Farm Credit Administration agencies were made by young farmers
and tenants. The increased prices of farm commodities were en-
couraging them to try to become farm owners. A large proportion
of the other applications were made by farmers interested mainly in
refinancing their debts for a long term of years in order to take
advantage of the existing low interest rates.
The passing of emergency financing among farmers with a reason-
able amount of collateral for farm-mortgage credit is indicated by
the decline in the number of applications for loans from the Federal
land banks andthe Land Bank Commissioner, and by the reentry
of private lending agencies into the farm-mortgage field. Appli-
cations for land-bank and Commissioner loans declined from 20,000
a week at the peak in 1933 to fewer than 3,000 a week in the summer
of 1935 and to an average of 1,620 a week by May 1936. Private
lending agencies- that were estimated to be doing only about 23
percent of the farm-mortgage business in the first quarter of 1934
and 49 percent during the first quarter of 1935 were doing approxi-
mately 70 percent of the business by the middle of 1936.
During the first half of 1936 new loans of the Federal land banks
were about offset by repayments and liquidation of loans as their
1389040—37 5 ++
58 YEARBOOK, 193 7
loans outstanding remained about steady. Commissioner loans out-
standing increased slightly. Loans made by other leading lending
agencies did not quite offset repayments and liquidation as their loans
outstanding continued to decrease, but at a reduced rate. Further-
more, there was some evidence in farm-mortgage recordings that
farm-mortgage loans made by individuals were on the increase.
Some debt distress persisted, however, in areas that had suffered
partial crop failures for several years, and among farmers whose
debt charges reflected previously excessive farm valuations. In spite
of this, the general situation had improved to the extent that Com-
missioner loans, which in ,amount are about 63 percent second-
mortgage loans, were decreasing at a more rapid rate than were the
land-bank loans made during the first half of 1936.
The principal backset to ,a more rapid improvement of the farm-
credit situation came when drought developed again this year. As a
result, there was an increased demand for loans for relief and
rehabilitation by midyear.
Farm-Mortgage Debt
It is unusually difficult just now to estimate the amount of the
total farm-mortgage debt in the United States because so much re-
financing has been done recently. Adequate statistics are not avail-
able to show the net changes produced by the delinquencies, the fore-
closures, the compositions, the extensions, and the charge-offs of
recent years. The last official estimate placed the amount at
$8,000,000,000 as of January 1, 1934. There are no precise data on
all the changes that have taken place since then, but indications are
that through foreclosures and other means the total has been brought
down somewhat from the 1934 figure. Needless to say, the amount
of the farm debt does not by itself indicate the financial position of
the farmers. Whether or not it is burdensome depends on the size
of the debt relative to the farm income out of which principal and
interest payments can be made.
Licensed member banks of the Federal Reserve System held farm-
mortgage loans amounting to $253,000,000 in the first quarter of 1936,
as compared with $263,000,000 in the first quarter of 1935. Farm-
mortgage loans held by agencies of the Farm Credit Administra-
tion totaled $2,869,089,100 in January 1936, as compared with
$2,586,206,691 in January 1935. These figures, however, do not
indicate the whole trend, as financing through other agencies is quite
important, though details are not available.
Farm borrowing for current production increased during the past
year. Agricultural prices were at the highest level since 1930, and
some expansion took place in farm acreage and livestock breeding.
Many country banks increased their loans to farmers for current
production, though frequently their total loans showed little change.
Lending by the production-credit associations of the Farm Credit
Administration increased. In May 1936 the outstanding loans of
these production-credit associations totaled $135,467,214, as compared
with $101,269,485 in May 1935. It is characteristic of the early
phases of agricultural revival for current production loans to in-
crease more rapidly than mortgage financing.
THE YEAR IN AGRICULTURE 59
Federal credit agencies during the year aided farmers through
low interest rates. Interest rates on outstanding Federal land-bank
loans, which had been temporarily reduced in 1935 to 3y2 percent,
were continued by legislation on that basis for the period ending
June 30, 1937. On new mortgage loans the Federal land banks con-
tinued to charge 4 percent per annum. Other financing agencies
offered low interest rates likewise, and the first half of 1936 saw
some increase in farm-mortgage lending. Feed and seed loans made
by the Federal Government, new lending by commercial banks, and
loans from the production-credit associations helped farmers in some
areas to pay cash for more of their supplies and reduced the volume
of costly store credit. The Eesettlement Administration enlarged its
activities in handling distress cases; and by April 1936 its total
loan commitments had risen to $53,793,000. After the drought the
volume increased more rapidly.
The drought, of course, is complicating the farm-credit situation
and delaying liquidation. Short-term credit by the Farm Credit Ad-
ministration agencies and by commercial banks amounted at the end
of 1934 to about $1,121,000,000. Other personal loans, store credit,
credit extended by implement firms, and loans negotiated by farmers'
cooperative associations made up an important additional amount.
Probably the total short-term credit outstanding did not change
greatly between the end of 1934 and the middle of 1936, as country-
bank loans outstanding continued to decline and outstanding short-
term loans by Farm Credit Administration agencies continued a steady
Character of New Short-Term Credit
As in the case of farm-mortgage credit, more important than any
change in the amount of short-term credit outstanding was the change
in the character of the new short-term credit being extended during
the first half of 1936. More of it was for productive purposes and
less of it for emergency financing of old debts. As an example, total
short-term credit extended by Farm Credit Administration agencies,
including the emergency and relief agencies during the first half of
1936 declined steadily and was less than for the same period the year
before. On the other hand, loans made by the production-credit
associations alone increased during the first half of 1936 and were
larger than for the same period a year earlier.
After the midyear, however, the drought increased the demand for
short-term credit of a relief nature, which had fallen off in the spring
months of 1936. Emergency crop loans and drought-relief loans out-
standing have steadily increased since 1929 and 1930 and now con-
stitute more than 40 percent of the total outstanding short-term credit
administered by the Farm Credit Administration. In addition, loans
or grants in the more distressed cases are being made by the Resettle-
ment Administration.
AGRICULTURAL TAXES
Tax levies per acre on farm real estate have changed on an average
very little in the last 3 years. They run about 54 percent above pre-
Avar (1913) level and about 36 percent below the level of the peak
year 1929. Factors governing the farm-taxation trend include, of
60 YEARBOOK, 193 7
course, the volume of the farm income, the expenses of local and
State government, and the extent to which taxing bodies rely on the
property tax for revenue. With respect to all these factors there are
some favorable indications.
As indicated earlier in this report, the outlook for the national farm
income is favorable despite this year's drought, though the regional
distribution will be extremely abnormal. There is a possibility of
continued economies in local and State expenses. Further drastic
cuts, however, are unlikely as great curtailment has already been
accomplished; moreover, local bodies may have to assume more re-
sponsibility for activities recently supported heavily by Federal aid.
As to the place of the property tax in State and local revenues,
progress is being made toward developing additional sources, and
toward shifting part of the burden from real estate to other forms of
taxpaying ability.
Some of the reductions that have been made in farm-realty taxation
are the result of curtailment in essential public services. For ex-
ample, school terms have been reduced and teachers' salaries lowered.
School budgets, in fact, have been drastically cut in many areas.
Belief and rehabilitation expenditures have been extremely heavy,
but the diversion of these expenditures to State sales and to Federal
taxation has been a factor in lowering the farm-tax burden. As yet
not much farm-tax relief has come from the reorganization of local
and State governmental machinery, though this method offers impor-
tant opportunities.
Improvement in farm income will have a dual effect on the farm-
tax situation. It will decrease the burdensomeness of any given tax
payment, but it will also lessen the economic pressure toward further
tax decrease and even toward continuation at the present level. As
mentioned above, many of the decreases in real estate taxes during
the past several years have been made possible by curtailment of
basic governmental services. Such curtailments have in many com-
munities been deplored and have been considered only temporary
expedients. With further improvement in the economic situation
and in farm income there undoubtedly will be a decided tendency to
restore the curtailed services to their previous levels. The tendency
probably will extend also to increases in any services which before the
recent curtailment had been locally considered as inadequate.
Over a long period of years preceding 1929 there had been a prac-
tically continuous increase in average farm real-estate taxes per acre
for the country as a whole. This is demonstrated by a preliminary
index computed by the Bureau of Agricultural Economics for the
period 1890 to 1913, coupled with the Bureau's current series
(1913-34) and a preliminary 1935 estimate. These series indicate an
increase of about 267 percent in farm real-estate taxes per acre from
1890 to 1935. General price levels for the period increased about
40 percent, but even if adjustment is made for the price factor,
there remains an increase of over 160 percent in farm real-estate
taxes per acre. This figure of 160 percent should not be assumed
to be altogether accurate, because changes in the general price level
may not well represent changes in the composite price of govern-
mental services, but it is believed to be a useful approximation for
THE YEAR IN AGRICULTURE 61
the present purpose. On the assumption that local-government effi-
ciency remained the same, these increases beyond the increase in
prices should largely represent increase in governmental services.
The importance of this trend as it affects the future is its sugges-
tion of a more or less constant demand for expansion of the services
furnished by local and State governments. So long as such demand
continues, there probably will be a decided tendency for farm taxes
to increase in periods when farm income is relatively satisfactory
and taxes are consequently less burdensome. The effect of this again
will be influenced by any substitution of other tax sources for real-
estate taxes.
There is heavy accumulated delinquency in farm taxation in many
States. The acreage delinquent seems to have reached a maximum
in 1932. Probably the amount of taxes delinquent continued to in-
crease until 1934. These arrears, which farmers are beginning to
pay up, often exceed their current tax bills, and farmers' tax pay-
ments in many cases will similarly exceed their bills for current
t&XGS
MARKETING AGREEMENTS
Marketing programs authorized in the original Agricultural Ad-
justment Act and modified under the subsequent amendments con-
tinue to help farmers to sell milk, fruits, and vegetables to better
advantage. As of July 1, 1936, there were in effect 39 marketing-
agreement, order, or license programs. They included 21 licenses
and 3 orders for fluid-milk markets, 1 marketing agreement and 1
license for the national evaporated-milk industry, 1 marketing agree-
ment for the national dry skim-milk industry, and 11 marketing
agreements supplemented by 4 licenses and 6 orders for 11 such
crops as fruits, nuts, and vegetables. With processors, handlers, and
farmers' cooperative associations acting together under these pro-
grams, destructive competition has diminished, and more stable mar-
keting conditions have been established. Launched as emergency
measures, the programs have come to be valued for permanent use.
Many of the more successful have been built on foundations already
laid by the farmers' cooperatives. Others have given the initial
impulse to cooperative marketing in various localities. They have
helped farmers to coordinate marketing with production and to
apply up-to-date methods of sorting, grading, and distribution.
After the decision of the United States Supreme Court in the
Hoosac Mills case, it became necessary to reorganize the administra-
tive set-up for dealing with marketing programs. Marketing activi-
ties that had previously been handled by the commodity divisions of
the A. A. A. were centered in the Division of Marketing and Market-
ing Agreements. Meantime, regional divisions were established for
administering the Soil Conservation and Domestic Allotment Act.
The A. A. A. continued to develop and administer marketing pro-
grams, because the sections of the act relating to these activities were
not before the court in the Hoosao Mills case. In subsequent suits,
however, the marketing-agreement provisions of the Agricultural Ad-
justment Act have been questioned. The issue is whether the Hoosac
Mills decision did or did not invalidate the mai'keting-agreement
features along with the crop-control provisions of the act.
62 YEARBOOK, 193 7
Final determination of the matter awaits action by the Supreme
Court. In two out of three cases considered by Federal district
courts, the marketing-program provisions of the Agricultural Ad-
justment Act have been upheld. In United States v. Hugh David
Edwards, Judge Yankwich, of the United States District Court for
the Southern District of California, found the marketing-agreement
and order sections of the act to be separable from the crop-adjust-
ment and processing-tax provisions. In United States v. David But-
tnoh et al., Judge Brewster, of the United States District Court of
Massachusetts, took a contrary view. He held that the marketing-
agreement and order provisions were inseparable from the crop-
control and processing-tax provisions. Later, in United States v.
Jerry BucJdey et al., Judge St. Sure, in the United States District
Court for the Northern District of California, continued in effect
a restraining order that had been issued to halt violations of an order
issued by the Secretary regulating the handling of deciduous-tree
fruits.
As required by the amendments to the Agricultural Adjustment Act
which were approved August 27, 1935, the Administration is replacing
licenses with orders and carrying out the other requirements of the
amended act. It has been possible to establish for various milk areas
conditions tending to give all the producers an equitable- share in the
market. The agreements and orders usually provide for the classifi-
cation of milk according to its use by the handlers ; for the payment
of minimum prices by handlers, and for the payment of uniform
returns to producers under pool plans. Programs for the marketing
of fruits and vegetables are simpler. They deal principally with the
rate at which produce is shipped to market and tend to adjust market
supplies more nearly to the prevailing demand. They affect, of course,
only commodities already produced and ready for market. Addi-
tional programs are being developed at the request of producers and
handlers, with the latter group showing an increased recognition of
the fact that they have a common interest with farmers in the main-
tenance of fair prices to producers.
Sukplus-Removal Operations
Surplus-removal operations have been developed as a supplement to
the marketing-agreement programs. The authority is section 32 of the
amendments of August 1935 to the Agricultural Adjustment Act.
This section makes available an amount equal to 30 percent of the
annual customs receipts for the encouragement of exports and the
diversion of surpluses to other uses. Congress has subsequently
amended it so as to include Government purchases of surplus farm
products for relief distribution. The funds it makes available are in
addition to congressional appropriations for the purchase of surplus
dairy products for relief distribution. Operations under the section
have dealt effectively with a number of farm-surplus situations,
though the method is not universally applicable.
Advantages have resulted both to producers and to the needy.
Surpluses that might otherwise have gone to waste have been moved
into consumption, with a net gain both in farmers' prices and in food
consumption among low-income groups. The purchases for relief
THE YEAR IN AGRICULTURE 63
distribution have included apples, citrus fruits, primes, pears, dried
beans and peas, onions; turnips, cabbage, carrots, and eggs. In addi-
tion, the funds available under section 32 have made it possible to
find new uses and new outlets for some farm products. More than
a dozen surplus-diversion programs are in operation, under agree-
ments between the Secretary and organizations of producers and
handlers. They include programs for walnuts, pecans, raisins,
prunes, dried figs, California fall and winter pears, dark air-cured
and fire-cured tobacco, peanuts, and cotton.
The diversion programs authorize purchase of the commodities
on the basis of grades or other requirements, at prices approved by
the Secretary of Agriculture. The industry groups sell the products
to anyone who will contract to convert them into byproduct or other
authorized uses. Differences between the prices received and the
prices paid for the products, plus incidental handling costs, are
made up out of section 32 funds. Other types of diversion programs
do not involve agreements between the Secretary and any industrial
group. In these cases the diversion payment goes directly to indi-
viduals who comply with the requirements. For example, in a pro-
gram designed to increase the exportation of pecans, the diversion
payment went to the exporters and represented the difference between
the domestic buying price and the export selling price.
The benefits have much exceeded the costs. Purchases of prunes
for relief distribution involved only a small outlay; but the opera-
tion prevented a disastrous break in prune prices, and in fact caused
an advance in the market for the entire crop. Frequently the diver-
sion of surpluses into relief or other channels outside the usual course
of trade brought about an increased distribution of the commodities
through ordinary trade channels. It had this effect because the
resulting price gain removed any incentive to let the products go to
waste. Certain of the diversion programs include efforts to develop
and expand uses for various products. In other cases, as for ex-
ample, the export program for pecans, the programs introduced the
commodity into markets previously unfamiliar with it.
Marketing Problems
The farmer's interest in marketing is less direct than his interest
in production, because as an individual he must take the marketing
system about as he finds it. It requires group action, such as the
organization of cooperative associations or the passage of legislation,
to make significant changes in the marketing system. There are
some things the individual farmer can do. He may choose between
grading his crop, or selling it field run; between selling it at harvest
time or storing it; and between selling it to a local buyer or to dealers
in central or terminal markets. Sometimes he can sell direct to the
consumers. Federal inspection services, and the Federal market-
news service, give the farmer increased facility in marketing. But
as an individual there is not much he can do to lower the costs of
marketing or to make the distribution system operate more smoothly.
Farmers believe, however, that substantial improvements can be
effected through legislation and through cooperative action. They
are impressed with the size of the national bill for transportation,
64 YEARBOOK, 1937
processing, and marketing. Even before the depression, in the dec-
ade of the 1920's, transportation, processing, and marketing absorbed
about 55 cents of the consumer's food dollar. At the bottom of the
depression these services absorbed about 67 cents. Since 1933 the
proportion left to the farmer has increased, but it is not yet back
to what it was before 1929. This fact is not in itself a proof that
marketing and distribution are inefficient or extortionate; but it is
evident that we need to be concerned with the cost of these services
fully as much as with the costs of production on the farm. The
whole subject needs thorough study ; and farmers' organizations show
an increasing awareness of the fact.
One way to reduce the costs of marketing and distribution is to
suppress unfair and dishonest trade practices and to prevent rack-
eteering. Enforcement of the Perishable Agricultural Commodities
Act, the Packers and Stockyards Act, the Grain Futures Act, and
the Food and Drug Administration Act has had a salutary influence.
Investigations by the Federal Trade Commission have raised the
standards of commercial practice. Trade regulation by State and
municipal authorities contributes to the same end; in fact, many
phases of agricultural marketing are necessarily in State and local
jurisdiction, since they do not affect interstate commerce directly.
But the problem usually transcends local or State lines. It is ob-
vious, for example, that the California artichoke grower has a direct
interest in preventing an artichoke racket in eastern markets. In
many cases Federal, State, and local authorities must cooperate in
preventing unfair trade practices, and perhaps in working out coordi-
nated programs for improvement.
Research and service agencies, both Federal and State, must go
beyond the provision of commodity inspection and market news, and
the suppression of unfair trade practices. There is need for a posi-
tive program to improve the marketing system. Much could be
done to promote efficient, low-cost handling of commodities, and to
improve both the placing and the timing of the distribution. Many
crops do not yet go to all the places where they could be profitably
sold, and do not reach all their possible markets at the most advan-
tageous moment. There is a field here for significant improvement.
But the problem is so intricate and involves so many aspects of
intercommodity competition that cooperative study seems indispensa-
ble to effective Federal and State action.
Rapid Progress Unlikely
It is unwise to expect extremely rapid progress. Our delicate and
complicated marketing system has evolved gradually, in response to
gradually changing conditions. Sudden and drastic overhauling
might wreck it. But adjustments here and there are urgently needed.
Recent years have seen important developments to which parts of
the marketing system have not become well-adapted. The growth
of large-scale processing and distribution raises new marketing prob-
lems. Motortruck transportation, commodity exchanges, and direct
buying also have an important bearing on the marketing process.
Study of these matters is a necessary preliminary to the development
THE YEAR IN AGRICULTURE 65
of a legislative policy that will bo fair to producers, distributors,
and consumers.
One part of the marketing machinery which obviously needs ad-
justment is the wholesale and jobbing markets for perishables. In
many large cities the cost of marketing and distributing perishables
seems unnecessarily high. City marketing facilities have not been
fully adapted to the motortruck, to direct purchasing by chain stores,
and to other recent developments. Competitive building of railway-
terminal facilities has tended to split markets and has added to the
costs of both buyer and seller. Trucking and rehandling could be
greatly reduced in many large cities through better coordination of
the available facilities. A related problem arises from the develop-
ment of regional or concentration points in the country. Several
types of regional markets have grown rapidly since the beginning
of the depression, and continuation of the growth will require research
to keep it on sound lines.
An alarming development is a tendency toward the exclusion of
outside foods from some markets and some States. Local protection-
ism of this type is profoundly repugnant to the spirit of our institu-
tions and diminishes the Nation's prosperity exactly in the same
manner as the excessive development of international tariffs dimin-
ishes the volume of international trade. Among the causes of- this
country's prosperity in the past, free trade among the States ranks
high ; and no consideration of a purely local nature should be allowed
to interfere with it.
In the handling of certain products, for example milk, health fac-
tors enter ; and the right of the several States to impose and enforce
sanitary regulations cannot be questioned. In other cases it may be
necessary to limit free trade in order to prevent the spread of insect
pests or diseases, or for other sound reasons of public policy. No
one should object to such legislation when it really contributes to na-
tional welfare. But there can be little doubt that in some cases the
welfare of consumers and similar considerations have been used as
an argument for regulations the main purpose of which is to benefit
one group of producers at the expense of other groups.
Such legislation, if it is effective at all, prevents efficient produc-
tion and efficient marketing. If carried to extremes it will raise food
prices and lower consumption without benefiting producers. Tempo-
rary advantages gained by producers in one locality may be nulli-
fied by retaliatory legislation in other localities. It is extremely
important to maintain among the States as high a degree of free
trade as is consistent with the other legitimate objects of public policy.
INSECT CONDITIONS
Climatic factors played an important part during the year in the
abundance and destructivoness of many major insect pests. The
tent caterpillar and canker worms continued to occur in outbreak
numbers in many sections of the Eastern States, and to- defoliate
trees over rather large areas. In the same general region, however,
the codling moth and the oriental fruit moth were less abundant
than normally. One of the introduced sawflies which feeds on grasses
and grains was unusually abundant and destroyed wheat plants in
66 YEARBOOK, 1937
certain parts of the upper Ohio Valley. Various kinds of cutworms
were destructively abundant generally throughout the region east
of the one hundredth meridian. The cotton boll weevil was less de-
structive than in average years. The cotton leafworm invaded the
fields unusually eai'ly, stripping the plants over large areas in Texas
and adjoining States in the Cotton Belt. The boll worm, or corn ear-
worm, was more destructive to cotton than in any year since 1929,
but was generally scarce in corn over the eastern half of the country.
It occurred in outbreak numbers in many sections in the west, and
caused material losses of tomatoes. The house cricket was unusually
abundant in many localities in the East. The abundance of these
and many other insects is affected rather directly by the weather
conditions. Some kinds, for example the periodical cicada, which
occurred this last spring generally throughout the United States, are
little affected by changes in weather conditions.
A few of the less familiar insect pests, such as the vetch weevil,
the pepper weevil, tomato pinworm, cherry scale, and vegetable
weevil, were found in new localities. A scale insect which had not
previously been reported from the United States was discovered in a
limited area in California and eradicated by the cooperative effort
of State and Federal agencies.
During the summer of 1935 grasshoppers occurred in outbreak
numbers in several of the Western and Middle Western States, but
not to the same extent as they did in 1934. During the 1935 season
the application of poison bait left over from the previous year mate-
rially contributed to reducing their numbers and protecting crops in
several of the more severely infested States of the northern Plains
region, particularly North Dakota. Drought conditions in the spring
of 1936 were, however, very favorable for the development of grass-
hoppers, and outbreaks, accompanied by material damage, occurred
in Nebraska, Iowa, Kansas, Missouri, Oklahoma, Minnesota, Mon-
tana, New Mexico, Arkansas, and eastern Colorado. This condition
was anticipated and State officials for those sections, where coopera-
tive surveys had been made the previous fall, were fully informed
as to the possibility of grasshopper outbreaks, together with the esti-
mate of the amount of material that would be needed to combat them.
The area surveyed did not include Missouri, Oklahoma, and Arkan-
sas, and accurate information was not available as to the sections
of these States where the outbreaks were expected.
Limited amounts of bait materials left over from the previous
control campaigns or secured through local and State agencies were
available in a few sections only. These amounts, together with those
secured with the special congressional appropriation of $250,000,
made late in June 1936, were not adequate to meet the need, and
farmers were urged to secure and distribute additional bait to pro-
tect their crops and reduce the numbers which menace next year's
crops. The grasshoppers developed into winged forms perhaps a
month earlier than usual and in the absence of food and effective
control moved generally throughout the area, including sections
where they had not been abundant previously.
The great numbers of chinch bugs that entered hibernation in the
fall of 1934 presaged the most-severe outbreak of this pest in 50
THE YEAR IN AGRICULTURE 67
years. Fortunately, the cold, wet spring which occurred over most
of the area was so destructive to the bugs that outbreaks developed
only in a few sections. It was, therefore, not necessary to use the
special authorization and appropriation for chinch-bug control in
the summer of 1935, and only $48,000 was expended of the $2,000,000
provided as an insurance fund to protect corn from bugs of the first
generation.
The European corn borer caused severe damage in limited areas
along the eastern seaboard, particularly to sweet corn. With the
aid of an allotment from emergency funds, a survey was carried on
to determine its spread, distribution, and relative abundance through-
out the previously known infested area. To determine the status in
the known infested area, 1,124 townships and 64 counties of 11 States
were surveyed. During this survey 5,817 fields and 32,578 acres of
corn were inspected. This survey disclosed that there was a general
increase in borer abundance through much of the infested area. To
determine the possible spread of the borer into new areas, scouts
visited 712 townships in 28 counties in 11 States, examining 14,690
fields, totaling 192,222 acres. New infestations were found in 237
townships, but all of these were adjacent to areas previously known
to be infested. This indicates that the spread had occurred largely
by natural means.
The infestation of screwworm, first discovered in the South-
eastern States in the fall of 1933, continued but was very materially
reduced, largely because of the adoption of methods of treatment and
handling livestock recommended during the cooperative educational
campaign in 1935. The special appropriation of $480,000 which pro-
vided for the cooperative educational campaign made it possible to
acquaint stockmen and others throughout the newly infested area
with the approved methods of combating screwworms. During the
summer of 1935 screwworms were unusually abundant throughout the
Southwest, where infestation has annually caused material losses to
cattle, sheep, and goats.
The educational and demonstrational work on screwworm control
was extended to this section in the spring of 1936, and is now being
conducted throughout the area infested by this pest. The extension
and continuation of the work is provided for by an additional special
appropriation of $460,000. The low temperatures which occurred
during the winter over much of this area, together with the effective
effort of combating the screwworm in areas where it overwintered,
urged as a part of the educational campaign, greatly reduced the num-
ber of screwAvorm cases throughout the infested area. While the re-
search to improve control measures should continue, the cooperative
educational work can be brought to a close during the current year.
Plant-Pest Control
The date palm scale, an important introduced insect which at one
time appeared to be the limiting factor to the development of date
culture in the Southwestern States, has been eradicated from the
United States. Continued intensive inspections failed to disclose the
presence of this pest, and eradication activities begun a number of
years ago were discontinued at the end of the fiscal year. At the same
68 YEARBOOK, 1937
time the quarantine regulating the movement of date palms in the
United States was withdrawn.
The restrictions governing the importation of plants likely to in-
troduce this and other pests continue in effect. These and other regu-
lations were studied, however, to determine whether conditions had
altered sufficiently to justify modification of the requirements. Two
special quarantines restricting the entry of pines were in fact re-
scinded, the evidence indicating that adequate protection was included
under another quarantine.
Regular activities carried on in cooperation with State agencies for
the control of plant pests were augmented by allotments from emer-
gency funds to provide relief employment. Trained workers planned,
organized, and directed the expansion of these activities so as to use
relief labor effectively. At the peak of the active season 25,242 work-
ers were employed in 1,497 counties in 44 States, and during the year
the work provided 21,398,000 man-hours of employment. The regular
activities expanded and benefited by this employment are : White-pine
blister-rust control; gypsy-moth control; phony -peach eradication;
citrus-canker eradication; barberry eradication; and the eradication
of the Dutch elm disease. In some instances, including the gypsy-
moth campaign east of the barrier zone, barberry eradication in Penn-
sylvania, West Virginia, and Virginia, and white-pine blister-rust
eradication in the Appalachian Mountain States, the work was ex-
tended into sections not previously covered with regular funds.
The brown-tail moth, an introduced pest which has been present
for many years in part of the New England States, though its spread
into other sections has been prevented by the enforcement of a Fed-
eral quarantine, was combated in the infested area by relief workers
employed under a special allotment. They destroyed millions of the
webs in which the pest overwinters. The work of destroying wild
cotton in southern Florida to eliminate the pink bollworm and pro-
tect the Cotton Belt against this pest, was expanded by relief em-
ployment. To lessen the risk of the spread of the dry-land form of
the cotton boll weevil, of which wild cotton is a native host, relief
labor employed under a special allotment located and destroyed
615,596 Thurberia plants in 163 square miles in the Tortollita Moun-
tains of southeastern Arizona.
With the aid of emergency funds, the eradication of peach mosaic,
a disease of major importance .to peach culture recently discovered
in certain western areas, was undertaken in cooperation with State
agencies. This infectious disease materially affects the growth of
the peach tree and causes the production of small knobby fruit of
little commercial value. It was first discovered in Texas. A few
infected trees were reported from western Colorado in 1934, and in
the spring of 1935 thousands of infected trees were located in three
western counties of this State. The only known way of combating
the disease is to locate and destroy infected trees. Through the co-
operative eradication effort thousands of infected trees were de-
stroyed in western Colorado during the summer of 1935. Surveys
so far conducted in 1936 disclose the presence of only a comparatively
few infected trees in this area and demonstrate the effectiveness of
the eradication work. Within the last few months the disease has
THE YEAR IN AGRICULTURE 69
also been located in parts of California, Utah, and New Mexico.
Plans to extend the eradication effort to these sections are being
perfected. Outlying infections may have been established through
the movement of infected nursery stock.
The Dutch elm disease, -which threatens the destruction of elms
throughout the country, is an important problem in plant-pest con-
trol. Only a small amount of regular funds was provided to combat
this disease. Allotments have been made from emergency funds and
the cooperative eradication work pushed. The personnel-selection re-
quirement, the necessity for training scouts and workers, and the un-
certainty as to when and in what amount funds would be available,
increased the difficulties. A few infected trees were found at out-
lying points, notably at Brunswick, Md., and Norfolk and Ports-
mouth, Va. ; Old Lyme, Conn. ; and Indianapolis, Ind. The infected
trees were promptly destroyed. In the more heavily infected area —
within a 50-mile radius of New York Hax-bor — the work included not
only the location and removal of trees known to be infected, but
also the location and removal of sick and dying trees, which may not
only harbor the disease but may also serve as breeding places for the
insect known to transmit the disease. All but a few of the 14,000
or so infected trees so far discovered in the United States were
destroyed at the close of the fiscal year. Scouting during the past
spring and early summer — the season most favorable for the location
of infected trees — disclosed the presence of only a few infected trees
as compared with the numbers discovered during the comparable
period in 1935. This appears to demonstrate the practicability of
eradicating the disease by methods used, the only ones known to be
effective. _
Research on Insects
Research to determine effective ways of combating insect pests has
continued along many lines. In the search for new insecticides, espe-
cially ones which will not leave harmful residues on the marketed
food product, the chemists have synthesized more than 100 organic
compounds which have been tested by the entomologists to determine
their effect on insects. In the initial tests some 20 of these, mostly
those in the azo group, were very toxic to insects and appeared to
hold promise for use in combating at least certain kinds of insect
pests.
Detailed studies of pyrethrum demonstrated that the chemical
formula for the toxic principles from pyrethrum flowers is much
simpler than had been believed. This discovery may make it pos-
sible to develop the active principles of these flowers synthetically.
At present our only source for this valuable insecticide is the im-
ported flowers, approximating 10 million pounds annually. New
compounds of nicotine have been made. Two promising ones are
prepared from nicotine and peat, one soluble and the other insoluble
in water. These are being tested on various insects including the
codling moth, the principal pest of apples. An improved method of
analyzing small amounts of nicotine opens up new ways of using
this material, particularly as a fumigant. It has been demonstrated
that the nicotine present in certain common types of tobacco is not
present as a glucoside. This discovery has a practical bearing on the
70 YEARBOOK, 1937
preparation of liomo-macle tobacco preparations used for control
of various insects.
Laboratory and field tests with organic insecticides, particularly
derris and cube, have brought many modifications in the recom-
mendations for the control of certain insect pests. It has been
demonstrated that these insecticides Avhich do not leave residues
objectionable from the standpoint of human health can be effectively
used against a number of different truck-crop pests, such as certain
cabbage worms and the Mexican bean beetle, and that they are effec-
tive against flea beetles destructive to growing tobacco. The further
usefulness of these recently developed materials is evidenced by the
determination that one application of sprays or dusts of derris or
cube is effective against the pea aphid over a longer period than
other recommended materials such as pyrethrum and nicotine. The
practicability of protecting sugar beets grown for seed purposes from
destruction by curly top by the application of pyrethrum and oil
as an atomized mist has also been demonstrated.
The low per-acre Aralue of most cereal and forage crops prevents
the use of direct measures to control certain important insect pests,
and cultural and biological control methods are not always effective,
particularly because community action is usually required. Various
varieties and strains of these crops have shown marked insect resist-
ance, and investigations along this line have been intensified. Cer-
tain strains of field corn have been demonstrated to have marked
resistance to the European corn borer independent of the time of
maturity of the corn. One of the important factors in cutting
down infestation is a delayed tasseling common to certain inbreds.
No resistant character has, however, so far been found in sweet-corn
varieties and strains which is not directly associated with date of
maturity. Strains of alfalfa entirely immune to alfalfa-aphid attack
have been obtained by selection. Marked progress has been made in
developing wheats suitable for California, Kansas, and Indiana con-
ditions which are resistant to the hessian fly. A variety of wheat
substantially immune to fly attack has been developed in California,
and the incorporation of this characteristic in varieties suitable for
commercial use is under way in cooperation with plant breeders.
Two varieties of soft red winter wheat highly resistant to fly attack
have been discovered in Indiana. Certain varieties of hard red
winter wheat have been discovered which may be utilized in pro-
ducing suitable wheats for production in Kansas and surrounding
States. Studies on chinch bug in sorghum and wheat have revealed
that certain varieties of both of these crops show marked resistance
to chinch-bug attack. The development and use of these may offer a
means of avoiding the heavy annual losses, including those occurring
during chinch-bug outbreaks, such as that of 1934. Certain varieties
of field and sweet corn are definitely less susceptible than others to
attack by the corn earworm. The practical possibilities of this dis-
covery have not, however, been determined.
Investigations to determine the possibility of using predacious and
parasitic insects as aids in combating injurious insect pests have been
extended to new fields and include such pests as the pea moth, the
lima-bean-r>od borer, and the pea weevil. An allotment from the
THE YEAR IN AGRICULTURE 71
sugar-processing-tax funds from Hawaii provided for expeditions to
Africa, South America, and the Orient in search of natural enemies
to aid in combating the Mediterranean fruitfiy and the melonfly in
Hawaii. The introduction of natural enemies of insect pests into
Puerto Rico, including an expedition to South America, was sup-
ported from a similar allotment from Puerto Rican tax funds. Eight
beneficial insects have already been recovered on that island, three of
which are well established and are being recolonized in parts of the
mainland. Cooperative observations in Cuba fully substantiated the
previous reports that the parasite of the citrus blackfly introduced
on that island in cooperation with the Cuban Government in 1930
is effective in controlling this pest and reducing the possibility of its
reaching our shores.
Studies on the secretions from the larvae of those species of flies
used in treating chronic ulcers and bone lesions disclosed that one
of;, the secretions is urea, a well-known chemical, which is widely
used and produced synthetically. Reports received from physicians
and surgeons who cooperated in testing urea produced synthetically,
and chemically identical with that in the fly secretion, suggest that
it contributes to the healing of certain types of wounds and has a
soothing and beneficial action on many kinds of skin infections as
well as deep-seated wounds. This discovery, if supported by further
investigations, may be of material benefit to the medical profession
and may reduce human suffering.
CHEMISTRY AND SOILS RESEARCH
Chemists in the Bureau of Chemistry and Soils have long been
engaged in developing useful products from agricultural raw mate-
rials such as straw, cobs, fruit, and vegetable culls, and other byprod-
ucts of agriculture. Farm byproducts constitute more than 60 per-
cent of the material annually removed from the land. These mate-
rials are part of the farmer's assets, as they are the fruits of his
labor and of the fertility of the land. The straw, stalks, hulls, and
other residues of the leading crops amount annually to more than
260,000,000 tons and contain approximately 115,000,000 tons of cel-
lulose, 66,000,000 tons of pentosans, and 53,000,000 tons of lignin. A
large proportion of this material, now wasted, is available for indus-
trial utilization.
Efforts by Department chemists to tap this reserve of potential
wealth have yielded substantial results, among the more recent of
which may be mentioned a process for making high-grade cellulose
from sugarcane bagasse, methods for producing furfural cheaply
from cobs or hulls, a continuous destructive-distillation process for
making charcoal and useful chemicals from various crop wastes, and
fermentation processes for the production of fuel gas, organic acids,
solvents, and residual cellulose fibers from crop wastes.
For the utilization of surplus agricultural products and culls the
chemists of the Department have developed processes for making
commercial products from citrus fruits, a process for the extraction
of starch for industrial uses from sweetpotatoes, and mold-fermen-
tation processes for making organic acids from corn sugar. Im-
proved methods of using cornstalks and cereal straws for making
72 YEARBOOK, 1937
high-grade papers have received much attention, though the compe-
tition of other raw materials impedes commercial progress.
Chemical research in the Department during the last year con-
tributed materially to the growing fund of knowledge of the utiliza-
tion of agricultural products and byproducts. In cooperation with
the Texas Agricultural Experiment Station, and using laboratories
furnished by local chambers of commerce, the Department's chemists
further studied the utilization of surplus citrus fruits, culls, and by-
products. They gave special attention to the production of fruit
juices and concentrates, alcoholic beverages, vinegar, marmalade,
candy, and volatile oil. Several commercial firms cooperated. That
this work is valuable is attested by the fact that the number of com-
mercial plants utilizing citrus culls in Texas increased from 3 in
1933 to 17 in 1935. In the same period the amount of money paid
annually to growers in that State for citrus culls increased from
$10,000 to $250,000.
In California investigators studied the production of wines and
brandies from surplus and cull deciduous fruits, the loosening of
stick-tight walnut hulls by ethylene, the preservation of fruit and
fruit pulps by freezing, and the production of sirups and concen-
trates from apples, pears, and dates. In cooperation with the Wash-
ington State College of Agriculture and Agricultural Experiment
Station, the Department established a new laboratory at Pullman,
Wash., known as the Fruit and Vegetable Byproducts Laboratory,
where it will investigate the utilization of fruits and vegetables
grown in that section.
Experimentation at Byproducts Laboratory
Work proceeded at the agricultural byproducts laboratory at Ames,
Iowa, on the production of cellulose, paper pulp, destructive-distil-
lation products, and fermentation products from crop wastes. In
these studies the Department cooperates with Iowa State College.
In cooperation with the New York Agricultural Experiment Station
at Geneva, 1ST. Y., the Department is investigating the utilization
of grapes, berries, and other fruits in the manufacture of commercial
fruit juices, wines, and beverages. In cooperation with Stanford
University the Department is studying at San Francisco the phar-
macology of insecticidal materials. In Louisiana with the assistance
of the Louisiana Agricultural Experiment Station, the Department
is investigating the influence of cultural conditions on the compo-
sition and workability of juices from different varieties of sugarcane
and the prevention of deterioration in harvested sugarcane during
short-time storage. In cooperation with the North Carolina Agri-
cultural Experiment Station the commercial fermentation of cucum-
bers into pickles and related products under southern climatic con-
ditions is being studied.
Commercial development of a process discovered in the Depart-
ment for producing sweetpotato starch is going forward under the
leadership of the Bureau of Chemistry and Soils, in cooperation with
the Bureau of Plant Industry and the Mississippi Agricultural Ex-
periment Station, at a plant operated by a farmers' cooperative
association at Laurel, Miss. In cooperation with the Alabama Poly-
THE YEAR IN AGRICULTURE 73
tecbnic Institute the Bureau of Chemistry and Soils established a
field laboratory at Auburn, Ala., to promote the industrial utiliza-
tion of sweetpotato starch. The Chemical Foundation recently
established a research fellowship in the Bureau to find new technical
uses for sweetpotato starch. Studies are in progress in cooperation
with the Mississippi Agricultural Experiment Station on the quality
and composition of sirups prepared from different portions of sorgo
stalks. Improved methods developed by the Department for making
sorgo sirup and sugarcane sirup are being introduced in Mississippi.
Alabama, and Florida. The Texas Agricultural Experiment Station
recently demonstrated the use of farm-scale equipment in making
high-grade sugarcane sirup by the Department's method.
Cooperation was extended from the Department to a commercial
firm in developing the improved nitric-acid process for producing
cellulose from bagasse. Cooperation with commercial firms ad-
vanced also the technique of utilizing byproduct milk sugar in
fondants for confectionery, and in determining the yield and quality
of paper pulp from wheat straw, flax straw, cornstalks, and arti-
choke tops. In the last-mentioned experiments the Department's
investigators used patented equipment designed for the production
of paper pulp from straw by a continuous soda cooking process at
atmospheric pressure.
Fundamental Research on Proteins and Enzymes
Fundamental research in the Bureau of Chemistry and Soils dealt
with the chemistry of proteins, enzymes, plant pigments, cuticle
waxes of fruits, lignin, turpentine, resin acids, and vegetable oils;
also with the chemistry and physics of soils, the chemistry and
physics of elements and compounds in fertilizer materials, the phar-
macology of insecticides that may contaminate fruits and vegetables,
and with microbiology as it relates to food spoilage, food prepara-
tion and preservation, industrial fermentations, and the curing of
hides and skins. As part of a basic-research program provided for
in the Bankhead-Jones Act of June 29, 1935, the Bureau organized
three new research projects. These are: (1) Research into the in-
dustrial utilization of the soybean and soybean products, (2) the
chemistry of enzymes and of enzyme action at low temperatures, and
(3) a study of the allergens of agricultural products. In addition,
chemists and plant pathologists will cooperate in a Bankhead-Jones
project for the study of plant viruses.
The work on soybeans and soybean products is going forward at
the Regional Soybean Industrial Products Laboratorj', which has
been established at the University of Illinois, in cooperation with the
agricultural experiment stations of the 12 Corn Belt States. Spe-
cialists from the agricultural experiment stations will cooperate with
chemists and agronomists from this Department. The object is to
improve the quality and increase the yield of soybean products, and
especially to develop industrial uses for them. It will include the
selection of types and varieties for particular purposes. In the fun-
damental studies of enzyme action several of this Department's bu-
reaus will cooperate. Special interest attaches to the little-under-
stood activity of enzymes at low temperatures because such activity
138904°— 37 6
74 YEARBOOK, 1937
affects frozen and cold-storage products in many ways. The work
on allergens should yield information about the chemical nature of
the plant and animal products known to cause physical ailments
such as rash, hives, hay fever, and asthma, in susceptible persons.
It has been estimated that 10 percent of the population is allergic.
Anticipating the eventual need for motor fuels other than gasoline,
the Bureau of Chemistry and Soils is expanding its investigations
into the possibility of producing such fuels economically from farm
products and byproducts. One line of research will explore the effi-
ciency of the microbiological conversion of starch and sugars into
alcohol or other liquid compounds having fuel value. In the produc-
tion of industrial alcohol in the past, it has always been necessary
to give due consideration to the possibility that the alcohol might
be used in such a way that its potability would be of primary im-
portance. However, in the production of power alcohol from farm
products potability is not a factor. It is possible, therefore, that
fermentative processes based on this conception of the function of the
end product may yield greater amounts of liquid fuel at a lower pro-
duction cost. It is planned to give careful attention to this phase of
the liquid-fuel problem. The possibility of using solid fuels, derived
from agricultural products, in internal-combustion engines will also
receive attention. _,
The Soil Survey
Another branch of the Bureau's work is the soil survey. Funda-
mental knowledge about the soil is more important today than ever
before and more generally appreciated. Efficient farming depends
essentially on suitable adjustments in plant-soil relationships, and
rational land utilization is impossible without knowledge of the soil
and its capabilities.
During the fiscal year 1936 the Soil Survey Division, in cooperation
with local agencies, mapped about 20,000 square miles of rural lands
in 31 States, Puerto Rico, and Hawaii. This work completed the
survey of Puerto Rico and brought the total area covered to more
than half the arable lands of the United States. The soil survey of
Hawaii will be completed during the present fiscal year.
At the present time the Department is cooperating with the agri-
cultural experiment stations of the seven States having an interest in
the watershed of the Tennessee River which, in turn, are cooperating
with the Tennessee Valley Authority for expediting the completion
of a detailed soil survey of this region. This survey is absolutely
essential in developing systems of agriculture for the improvement
of the land and the protection of the reservoirs.
Information obtained from the survey of areas in Western States
has permitted an extension in the acreage of certain special crops,
and has indicated the areas where the accumulation of salts and
the development of alkali would be a menace to irrigation projects.
Progress has been made in the development of a system for rating
the various soil types according to their productivity for adapted
crops and an increasing number of published soil surveys contain
tables showing the inherent productivity of the soil as well as its
productivity under different systems of management.
THE YEAR IN AGRICULTURE 75
Tho Soil Survey Division prepared a special report on the charac-
teristics and distribution of various kinds of organic soils and peat
in the Pacific Coast States. This report paid special attention to
the problems of soil conservation and flood prevention.
In July 1935 the Department issued C. F. Marbut's work, entitled
"The Soils of the United States", which constitutes the final section
of the Atlas of American Agriculture. This gives the accumulated
results of the Department's soil surveys and brings into a focus the
findings regarding soils as gained by Dr. Marbut and his associates
during the last 35 years. It contains maps showing the areas cov-
ered by soil surveys up to June 1934, the distribution of the soil
groups, the distribution of the parent materials of soils, and the
distribution of soils without normal profiles.
An especially important feature is a large map of the United
States in 12 sections showing the distribution of the country's soils
according to 137 differentiated and 6 undifferentiated soil groups.
There is also information on the classification of soils, their geo-
graphic relationships, their derivation and development, and their
profile characteristics, as well as their physical properties and chemi-
cal composition. This report is the culmination of Dr. Marbut's life
Soil Chemistry and Physics
The Bureau of Chemistry and Soils is carrying on research on the
chemistry and physics of soils to develop fundamental knowledge on
composition and properties which has an important bearing on soil
classification, soil conservation, and soil utilization, as well as on varia-
tions in the yield, composition, and food value of crops. It is also
studying the causes for nonfertility of certain soils, the effects of
arsenical insecticides on soils, and the value of peat as a soil amend-
ment. During the past year several important publications have been
issued as a result of these investigations. One of them, Technical
Bulletin 484, presents analytical data for eight soil profiles, repre-
senting six of the great groups of soils, which show that the colloids of
the great groups of soils differ from each other and that there exists
a chemical basis for the characteristics of soils as manifested in the
field. Another, Technical Bulletin 482, reports the results of studies
on the occurrence of selenium in the soils of the United States. A
second bulletin on this same subject is in process of publication.
Additional seleniferous areas have been found which produce toxic
vegetation. Kesults of recent -surveys indicate that toxic seleniferous
areas are ordinarily found in certain geological formations. New
areas where the soils are likely to be seriously seleniferous, judging
from geological data, are now being explored. There seems to be no
definite relation between the quantity of selenium in a soil and the
quantity taken up by plants growing on it. The distribution of
selenium in soils has been shown to be very widespread, and its pri-
mary source appears to be from volcanic activity. Its occurrence in
small quantity in wheat appears to be world-wide.
Soils from the erosion experiment stations were studied with re-
gard to the relationships between their physical constants. The
same soils were examined by newly developed methods for certain
elements which occur onlv in minute quantities and are not ordi-
76 YEARBOOK, 1937
narily included in soil analyses. Selenium, arsenic, copper, cobalt,
nickel, zinc, barium, chromium, and vanadium were found in de-
terminable quantities in each of the 11 profiles examined. The
quantities varied from less than 0.1 part per million for selenium,
cobalt, and nickel to as much as 708 parts per million for barium.
It is becoming increasingly apparent that these and other trace
elements play an important role in soil behavior, as well as in plant
nutrition and the food value of agricultural products. More exact
knowledge concerning the chemical composition of soils, including
their content of trace elements, will be essential in connection with
a very comprehensive and fundamental cooperative research project
that is being planned by the Bureau of Chemistry ' and Soils to
determine the effects of soil, fertilizers, climatic conditions, crop
rotation, cultivation, and variety of plant on the mineral and other
constituents of plants and the value of plants for food purposes.
Fertilizers
Fertilizer studies demonstrated that the elimination of filler from
fertilizers would save the farmers of the United States about $7,500,-
000 annually. It appears also that the purchase of double-strength
mixtures, which can be manufactured without difficulty, would re-
sult in substantial savings. Nationally, the United States is self-
contained as regards the principal fertilizing elements, and scientific
research in this Department has contributed to the development of
commercial fertilizer production. Interest is turning now to the
comparatively recent recognition of the fact that mixed fertilizers
should contain neutralizing agents to prevent the development of
soil acidity. Research is advancing the production of fertilizer mix-
tures that are nonacid forming. One useful method is the use of
ground dolomitic limestone.
Interest is growing also regarding the proper placement of fer-
tilizers with respect to seed and plants, and the Department has de-
veloped a granulating process for mixed fertilizers to prevent the
segregation of materials. Recent work on calcined phosphate indi-
cates that the plant-food value of this product is as high as that of
commercial superphosphate, and that the calcining process offers
attractive possibilities for the production of phosphate fertilizer at
low cost. A process has been developed in the Department for the
production of potassium metaphosphate from potassium chloride and
phosphoric acid. This product holds much promise as a fertilizer
material because it consists almost entirely of potash and phosphoric
acid and does not absorb moisture from the air. Also the Depart-
ment has developed new compounds of urea with magnesium sulphate
and magnesium nitrate which are useful for incorporating the sec-
ondary plant nutrient, magnesium, in fertilizer mixtures, as well as
nitrogen.
New fundamental scientific knowledge has been acquired through
basic research on the chemical and physical properties of elements
and compounds contained in fertilizer materials, on the principles
underlying catalytic action in industrial nitrogen-fixation processes,
and on the fixation of nitrogen by living organisms and organic ma-
terials. The facilities of the Bureau of Chemistry and Soils for
THE YEAR IN AGRICULTURE 77
modern physical and physicochemical research have been used to as-
sist other bureaus of the Department having problems in this field.
Thus, in cooperation with the Bureau of Plant Industry, the effect of
X-rays on corn seed and tobacco plants was determined and spcc-
troanalyses were made of the differences in the mineral elements
content of toxic and nontoxic specimens of the roots of Tephrosia
{Cracca) virginiana (devil's shoestring) which were under investiga-
tion as a source of insecticide.
Chemistry and the Farmer
Both hopes and fears cluster about the possibilities of chemical
research and its bearing upon new uses for the products and by-
products of the farm. Enthusiasts foresee important new markets
and a quick solution of the whole farm problem. Warning voices
say the chemist will synthesize foods in the factory and put the
farmer out of his job. Industrial chemistry, they point out, has no
particular preference for agricultural sources of raw material and
may find what it wants elsewhere. Botli the hopes and the fears
should be discounted. There is no possibility either that chemistry
will solve all the farmers' difficulties overnight or that it will do away
with the need for farms.
The worth of a chemical discovery depends on the economic as
well as the technical factors. Such things as cornstalks and cereal
straw, for example, have some value as feed for livestock and as
fertilizer. It pays the farmer to sell them for industrial utilization
only when he receives more from their sale than they are worth to him
as feed and manure. After the chemist has demonstrated that an
industrial use for a farm product is possible, the manufacturer must
test its commercial feasibility. Also, the farmer should remember
that the development of new uses for one of his products may hurt
the market for others.
In like manner we may discount the fears generated by the prog-
ress of industrial chemistry. Chemists have synthesized a small
number of organic compounds formerly obtained from plants, but
man must still apply to nature direct for food, clothing, and shelter.
Probably agriculture will always have to produce most of the food
substances that man requires, most of the clothing materials, and a
good part of the materials required in providing shelter. In any case
the change of emphasis is not likely to be appreciable in the near
future. For as far ahead as we can see, chemistry will aid and not
supplant the farmer.
There is, however, a side of the industrial-utilization problem which
should be considered carefully. Chemical discovery, like other
aspects of technical progress, is not necessarily an unmixed blessing,
particularly to the farmer. If it opens new possibilities, it creates
also a need for readjustment, especially when it affects intercommod-
ity competition. For example, the utilization of sugarcane bagasse
in the manufacture of rayon may diminish the demand for cotton.
Soybean-oil productionj stimulated by a demand for soybean prod-
ucts in the automobile industry, may come directly into competition
with cottonseed and other vegetable oils. Sometimes, too, the devel-
78 YEARBOOK, 1937
opment of new uses for farm products attracts more people into
farming and disturbs the balance between town and country.
Such considerations should not deter chemical research, for science
cannot foresee all the probable consequences of its discoveries. That
is beyond human wisdom. But the exploitation of particular prod-
ucts is not the only thing to keep in mind. Success in that direction
Avill inevitably benefit some groups more than others, and public
agencies engaged in chemical research should cooperate with other
branches of the public service in promoting the most nearly equitable
distribution of the benefits. There is special need for the collabora-
tion of chemists and economists.
This Department endeavors simultaneously to promote the interests
of producers, manufacturers, and consumers, because it is interested
not only in the production but also in the commercial utilization and
final consumption of agricultural commodities. While the work of
the chemist in creating new uses for farm products may temporarily
benefit some lines of production to the disadvantage of others, the
Department believes the final balance will usually be in favor of the
farmer.
It is important to prevent the unscrupulous exploitation of pro-
ducers or would-be producers on false grounds. There are opportu-
nities in parts of the United States for the culture of the tung tree.
But land unsuited to that purpose is being sold to gullible investors.
The same thing has happened in the case of hemp ; and the sale of
land is not the only means of diverting technical progress to improper
ends. Everyone should understand that hard-headed cost accounting
and commercial research are necessary to get the best results and that
the laboratory discovery is only the first step, which may not be fol-
lowed for a long time by the final demonstration on a commercial
scale. In the files of this Department are recorded scores of chemical
discoveries and innovations, which, though technically successful,
remain unutilized commercially for years because the original costs
were too high. For example, the Department developed a process,
using dilute nitric acid as the pulping agent, for making high-grade
cellulose from bagasse. But it was not until ways had been found to
cheapen the production of the acid that the process became commer-
cially practicable. Premature exploitation of research findings is a
constant source of loss to investors and producers.
UTILIZATION OF DAIRY BYPRODUCTS
Investigations in the Bureau of Dairy Industry to develop ways
to utilize whey or its separate constituents more efficiently have given
promising results. The whey produced annually in the United
States, as a byproduct in the manufacture of cheese, contains about
300,000,000 pounds of milk solids. Yet whey is commonly wasted or
used only in limited amounts as feed for pigs and poultry. Dairy
investigators have long considered this practice inefficient. They
regard the feeding of whey to livestock as justifiable only until better
methods of producing human food from whey can be developed.
Whey contains nearly half the food solids of milk. It contains
all the valuable sugar and at least one vitamin, so that it possesses
exceptional nutritive properties. Yet it has found few uses as
THE YEAR IN AGRICULTURE 79
human food because it has no pleasing taste itself, and no special
ways have been developed heretofore for using it. Within the last
year the Bureau has found that whey may be used to enrich a variety
of food preparations by taking advantage of its chief distinguishing
characteristic, which is its lack of casein.
Casein is the substance that causes coagulation in milk under high
temperatures or in the presence of acid vegetables or fruits. Manu-
facturers of vegetable soups can use condensed whey, whey powder,
or whey cream in place of normal milk or cream to enrich their
products. The whey solids Avill cause less difficulty with coagulation,
the soups will retain their natural color better, they will have the
characteristic milk flavor, and a greater nutritive value than soups
made without milk solids.
The solids can also be combined with highly acid fruit juices, such
as orange, grapefruit, strawberry, and similar fruits. Because of
the high acidity of the combination little heat is required for sterili-
zation, and these beverages and whips may be canned without a
cooked flavor. > By varying the combinations, sterilized whips, fruit
drinks, and mixes suitable for freezing in a mechanical refrigerator
can be made available to the housewife. These are probably only a
few of the ways in which whey solids may be combined with other
materials to improve old or create entirely new food products.
Young pigs will grow satisfactorily on pasture supplemented with
whey, but it is often a problem to adjust the supply of whey to the
requirements of the growing pigs. In the flush season there is likely
to be a greater supply of whey than the pigs can consume. The
Bureau's investigations^ indicate that surplus whey can be acidified
with an active lactic-acid culture and concentrated at the factory to
make an acid product that can be held until it is needed for feeding.
Also, to provide, for feeding roughage and whey when pasture is not
available, concentrated sweet whey may be mixed with grass or alfalfa
and ensiled. Preliminary trials show that pigs will consume this
ration and make satisfactory growth.
Information developed in the Bureau's laboratories has found ex-
pression in a number of new commercial ventures. Cheese of the
Roquefort type is now being made by a small factory which uses an
abandoned coal-mine shaft for a curing room. The ideal natural
temperature and humidity conditions of the shaft eliminate the neces-
sity of providing artificial curing conditions. Arrangements have
been made to start a similar operation in which a natural cave will
provide the right conditions for curing. In one factory, with rooms
artificially cooled and humidified, the Bureau's method for manufac-
turing a soft cheese of the Italian Bel Paese type has been estab-
lished. A dairy-byproducts company has built and is successfully
operating a factory for the manufacture of lactic acid by fermenting
whey. A large volume of whey is being utilized.
Experimental shipments of concentrated frozen milk have been
made tothe Canal Zone under the Bureau's direction, to determine
the feasibility of providing fluid milk in the Tropics, on shipboard,
and in other places where good-quality milk is unobtainable or the
supply is inadequate. Research in the Bureau has demonstrated that
milk may be concentrated to one-third of its volume, or less, held at
80 YEARBOOK, 1937
*
temperatures below freezing for weeks, and then brought back to its
original volume by adding water, without losing the characteristics
of fresh clean-flavored milk.
ANIMAL INDUSTRY
Superior types of livestock continue to be one of the most promis-
ing means of increasing the efficiency and economy of production.
Great variation in the growth of pigs, similar in outward appear-
ance, has occurred at the National Agricultural Research Center,
Beltsville, Md. Under the conditions of management and on identi-
cal rations, pigs of the same litter varied as much as 100 days in the
time required to attain a weight of 225 pounds. And within the
same breed the quantity of feed required by different litters to make
100 pounds of gain varied from 325 to 500 pounds. Such observa-
tions indicate the feasibility of selecting the breeding hogs that are
naturally fast and economical growers. There are indications also
that rapid growth is associated with tenderness in meat.
Studies with Danish Landrace hogs imported a few years ago have
now reached a stage to permit comparisons with American-bred hogs.
When the chilled, dressed carcasses of 40 Landrace hogs and 36 of
2 American breeds were compared, the former had the higher per-
centage of ham, loin, and bacon and lower percentages of picnic
shoulder and head. The higher yield of bacon in the Landrace hogs
is especially noteworthy. In general, the Landrace hog excelled in
the production of the more valuable cuts of pork.
In the study of more efficient cattle production, the Department
has sought a type of animal that will produce beef profitably under
adverse conditions of heat and insect pests. Such cattle are es-
pecially needed in the Gulf coast region and in other sections having
a similar climate.
Crosses between Brahman cattle and several beef breeds already
established in the United States have given promising results.
Cross-bred types developed from the Guzerat (Brahman) and the
Aberdeen Angus breed have shown high adaptability to semitropical
conditions. The second generation of calves carrying three-fourths
Aberdeen Angus blood and one-fourth Guzerat have, in all instances,
been polled and black. A noteworthy result is the increased weight,
at weaning age, of cross-bred calves over purebred Aberdeen Angus
calves. First crosses, containing 50 percent of the blood of each
breed, averaged 455 pounds, whereas Aberdeen Angus calves aver-
aged 391 pounds. Second-cross calves, possessing three-fourths
Aberdeen Angus and one-fourth Guzerat breeding, averaged 491
pounds at the same age. These results are in the direction of im-
provement both in adaptability to the region and in desired market
characteristics.
Other breeding studies have been supplemented with tests on the
tenderness of the resulting meat. Four years' experimental work has
shown that roasted rib cuts from grade Hereford cattle were more
tender than corresponding cuts from cattle of native breeding
slaughtered at the same age. These studies indicate the presence of
hereditary differences in fat distribution and tenderness.
THE YEAR IN AGRICULTURE 81
In a comparison of methods of wintering cattle under "western-
range conditions experiments showed wide differences in costs. When
breeding cows were kept on reserved creek bottom and allowed to
graze sagebrush range supplemented by 83 pounds of cottonseed
cake per cow, the wintering cost per animal was $2.84. The cost of
wintering similar cows on alfalfa hay at the rate of 765 pounds per
head was $4.51. Experiments of this kind indicated the economies
possible by altering systems of management. When applied to large
herds of cattle, even small differences of the kind cited result in
large savings and impressive net profits.
A valuable scientific aid in sheep breeding and in the raising of
other animals for hair or fur is a device recently developed in the
Department's animal-fiber research laboratory. The instrument
makes possible the procurement and study of very thin cross sec-
tions of fiber in a few minutes' time. The various characteristics of
fiber associated with suitability for commercial purposes are readily
observed by the use of this device. Already it is being used in many
fields of industry. Still another instrument developed in the same
laboratory during the year makes possible the measurement of length
and crimp of wool and hair fibers in a more accurate and efficient
manner than with previously available equipment.
Foreign Breeds Introduced
In connection with improvement of animal types the Department
has obtained from various foreign sources species and breeds of
livestock having noteworthy characteristics. Such stock, introduced
in 1935 and 1936, includes Nonius horses and Puli sheep dogs from
Hungary, red Danish cattle from Denmark, and south Devon cattle,
large black hogs, white Austrian turkeys, and White Wyandotte
chickens from England. After receiving veterinary inspection and
meeting other quarantine safeguards these animals were admitted
to Department experiment stations for breeding and feeding studies
and related observations. To some extent also they are being used in
cross-breeding experiments with selected types raised in the United
"" ' Security From Livestock Diseases
Each year the livestock industry of the United States becomes
more secure from diseases, parasites, and other pests. Through
methods supplied by scientific research, stockmen and their veterinary
allies have recently extended the frontiers of animal health very
materially. A brief appraisal of the animal-disease situation at the
end of the last fiscal year indicates several noteworthy advances in
this field.
Bovine tuberculosis has been practically eradicated from 40 of
the 48 States in the Union and from 95 percent of all the counties.
There is considerable need, however, for continued retesting of herds
to locate and eradicate any remaining infection. Cattle carcasses
which, because of tuberculosis, failed to pass Federal inspection at
the principal livestock markets numbered less than 10,000 in 1936
as compared with more than 28,000 the previous year. Condemna-
tions of parts of cattle carcasses likewise were much less, being about
half as many as during the previous year. A reduction in tubercu-
82 YEARBOOK, 1937
losis, though in less degree, was observed also in swine. These
figures, based on official veterinary inspection of millions of animal
carcasses, signify a large saving of meat as well as an unmistakably
improved condition in the health of cattle and swine.
Extensive public interest in the elimination of Bang's disease, or
infectious abortion, has caused the Department to continue the test-
ing of cattle in cooperation with State officials and livestock owners.
Agglutination blood tests for the detection of this disease were ap-
plied to approximately 6,600,000 cattle. About 7 percent were re-
actors as compared with 11 percent during the preceding year. The
elimination of Bang's disease, which has in the past caused heavy
losses and much discouragement in cattle breeding, has resulted in
greater optimism among dairymen and others whose herds have thus
been placed on a more secure health basis.
In search of an improved diagnostic agent for the identification
of cattle affected with this disease, the Department recently developed
a biological product known as a stained antigen for the purpose.
This product makes possible a rapid whole-blood test, which has
several practical benefits over the present slower and more expensive
methods of diagnosis. A thorough field trial of the new method was
begun by the distribution of sufficient stained antigen for testing
13,000 cattle under Department supervision.
In the eradication of the cattle fever tick the area in continental
United States still under Federal quarantine has been reduced to only
9 percent of its original size. The sections still infested with ticks
are confined to jparts of three States — Florida, Louisiana, and Texas —
in contrast to infestation of 15 States when the work began in 1906.
Systematic eradication of cattle ticks was recently begun in Puerto
Bico.
Control of hog cholera has reached the point where immunization
by the serum-virus treatment, developed by the Department, is largely
a routine procedure. The method is widely known ; serious outbreaks
of the disease are infrequent ; and the Department has largely relin-
quished direction of control work to the States. However, it con-
tinues to supervise the preparation and distribution of the virus and
serum, of which a total of more than 500,000,000 cubic centimeters
was produced last year under Federal licenses. As a means of assur-
ing adequate production of these products for possible emergencies,
the Department has aided manufacturers in perfecting a marketing
agreement directed toward this end.
A New Immunizing Product
As a still further measure of hog-cholera control, the Department
recently developed a new immunizing product. Known as crystal-
violet vaccine, this product has given distinctly encouraging results
in experimental trials. It has provided approximately 99 percent
satisfactory protection and has several advantages, including greater
safety, over the familiar serum-virus method of immunization. Dur-
ing the last year commercial production of the vaccine on a small
scale was sanctioned by the Department in order that this new product
might be thoroughly tested under various field conditions. "Until the
merits of the vaccine are more thoroughly established, however, reli-
THE YEAR IN AGRICULTURE 83
ance must still be placed in the serum-virus treatment, the efficacy
of which, when properly administered, has been fully established.
A present limitation of the crystal-violet-vaccine method of immuni-
zation is its slowness in furnishing protection. Immunity does not
appear to be established usually until at least 2 weeks after a hog has
been vaccinated.
The drought of 1934, with resulting extensive shipments of live-
stock, retarded several lines of livestock disease-eradication work.
Some spread of scabies in cattle and sheep occurred in Central and
Western States, but scabies of horses now appears to have been eradi-
cated, inspections revealing no cases during the year. The eradication
of the horse disease, dourine, likewise appears to be virtually accom-
plished, but State authorities are continuing the quarantine of a few
areas where the presence of the disease is suspected. Any remaining
infection is considered to be very slight, judging from the evidence of
only one animal giving a positive reaction to this malady within the
last year.
A comparatively newly identified disease of horses and other equines
has caused anxiety as well as serious loss in several localities. Known
as infectious encephalomyelitis, and occasionally by such nonspecific
terms as blind staggers, brain fever, and sleeping sickness, this malady
has appeared in no less than 20 States. It is caused by an infectious
virus which produces nervous symptoms resulting from inflammation
of the brain and spinal cord. The mortality is high, and in animals
that recover there may be permanent impairment of the brain. Out-
breaks occur chiefly during the summer and fall months and in low-
lying and moist areas. The use of a specific serum has been helpful
in preventing the spread of infectious encephalomyelitis, but it pro-
duces only a short-lived immunity. The Department is studying the
disease and testing various biological products and drugs reported as
being beneficial for its prevention or treatment.
Anthrax caused comparatively slight loss during the year, no serious
outbreaks being reported to the Department. Assistance in prevent-
ing the disease was given to Indians on reservations where outbreaks
occurred several years ago. The horse disease, glanders, which at one
time caused heavy losses, has been practically eradicated.
Recent research has disclosed several highly effective methods of
combating injurious internal parasites? such as kidney worms of swine
and liver flukes of cattle and sheep. Livestock owners have been quick
to adopt and apply the Department's recommendations. In several
instances supplementary benefits derived have greatly exceeded the
original purpose of control methods.
For instance, Department investigators have shown that drainage
of wet, marshy, and boggy pastures is the most practical procedure
for controlling liver flukes. In several areas these parasites were kill-
ing as many as 50 percent of the sheep and stunting or killing calves.
The broadcasting of copper sulphate to destroy the snail intermediate
host is, at best, only a temporary expedient and must be continued
from year to year in order to insure the destruction of the fresh crops
of snails which reappear sooner or later. Drainage, on the other hand,
is an effective bulwark against aquatic snails, which invariably perish
on dry land. Eecently reclaimed boggy meadows contained thousands
84 YEARBOOK, 1937
of dead snails, many of which were the potential and actual conveyors
of the liver fluke that is deadly to sheep and injurious to cattle as well
as to several species of wild animals.
But besides controlling liver flukes, the drainage of wet pastures has
produced a marked change in the type of vegetation. The coarse
aquatic grasses containing little or no nourishment for livestock grad-
ually disappear as the pastures become dry ; and, as a result of natural
seeding, highly nourishing forage, including clover, timothy, and
other nutritious plants, take their place. This results in a permanent
improvement of the land; and, with reduced water in the soil, the
land produces good forage earlier in the spring and later in the fall.
In the Western States where liver-fluke control is in progress drain-
age of marshy meadows makes considerable water available for irri-
gation. In Utah, particularly, the water from the drainage ditches is
being diverted into irrigation canals, thereby adding materially to the
supply of water available for irrigation. Incidentally drainage of
wet and boggy lands has considerable value as a mosquito-control
measure.
In short, the control measures for liver flukes are not only effective
in reducing serious losses in sheep and stunting in cattle but are also
of marked value in converting submarginal lands into productive pas-
tures, adding to the available water supply of areas dependent on
irrigation, and aiding in the control of mosquitoes.
Pullorum disease, a major drawback to poultry raising, is being
controlled by progressive flock owners through the use of the rapid
whole-blood test developed by the Department a few years ago. Com-
mercial production of the stained antigen used last year in making the
test was sufficient for testing more than 10,000,000 fowls. Under the
provisions of the national poultry improvement plan thus far adopted
by 34 States, the Department approves the quality of all this antigen
used in official testing, thus insuring a high quality of this diagnostic
agent.
Besides these advancements in curbing losses from livestock diseases,
the Department has continued its quarantine and inspection services
against the possible introduction of infection from abroad. During
the year the United States remained entirely free of foot-and-mouth
disease, rinderpest, surra, contagious pleuropneumonia, and other mal-
adies that cause heavy losses to livestock owners in some foreign
countries.
The increase of about 7 percent in enrollment reported by the 10
federally accredited veterinary colleges of the United States augurs
well for continuing the foregoing measures for the protection of the
Nation's livestock.
Supervision of Livestock Marketing
Supplementing its regulatory work of veterinary character, the
Department has sought to improve conditions of livestock market-
ing. Several noteworthy developments of the year resulted from
procedures under the Packers and Stockyards Act.
Three cases involving orders of the Secretary which prescribed
reasonable commission rates and stockyard charges at Chicago, 111.,
and St. Joseph, Mo., were upheld by the United States Supreme
THE YEAR IN AGRICULTURE 85
Court. As a result legal action lias been taken in the lower courts
for the return of excess commissions and stockyards charges to
shippers. The amount of such returns involved probably will ex-
ceed $1,000,000. The decisions of the Supreme Court were im-
portant and significant in that they sustained procedures followed
by the Department in determining stockyard charges and commission
rates.
Congress amended the Packers and Stockyards Act during the
year to include the supervision of poultry marketing in a manner
similar to the supervision of the marketing of other classes of live-
stock. The amendment provides for the licensing of persons en-
gaged in furnishing facilities or rendering services for marketing live
poultry in interstate commerce in cities designated by the Secretary
of Agriculture. The regulation of rates and practices of licenses
is a further provision of the amendment.
Investigations of the poultry-marketing situation, together with
requests for supervision from a number of cities, resulted in the des-
ignation of poultry markets in 15 cities as being subject to Depart-
ment supervision, up to the close of the fiscal year 1936.
FORESTRY
Most people have regarded forestry as largely a means of assuring
an adequate future supply of timber, and it should, of course, be
valued for that purpose. Four-fifths of our commercial forest land,
and at least 90 percent of its potential productivity, are in private
ownership; and private ownership has not generally endeavored to
maintain a continuous timber harvest. It is extremely important,
therefore, to promote sustained-yield practices on the publicly owned
forest land and to encourage such practices on the privately owned
land. Sustained forest production is essential for the general wel-
fare. But forestry has other ends as well, notably the conservation
of soil and of water — in other words, the prevention of erosion and
of floods. Fortunately, the methods which conserve timber produc-
tivity at the same time promote the other objects of scientific forestry
so that no conflict arises. Curbing forest exploitation is good for
the timber industry and also for the public interests that depend upon
the forests. This Department recommended, and Congress in part
approved during the last year, a program for coping with some of the
responsibilities involved.
That a common interest extends to all forest lands and that private,
as well as national, forests ought to be managed on a sustained-yield
basis is now generally acknowledged. There is a public, as well as a
private, obligation. Accordingly, fire protection by the Civilian Con-
servation Corps under the direction of the Forest Service is under
way on private, as well as public, forest lands. The expenditure on
private lands for this purpose has already exceeded $58,000,000. For
the current fiscal year Congress has appropriated increased funds for
forest-fire protection by Federal agencies in cooperation with the
States and with private owners. Forest research carried on by the
Forest Service similarly benefits public and private land ownership,
through its influence on the utilization, as well as the production, of
timber.
86 YEARBOOK, 1937
Federal acquisition of forest lands through purchase was first
authorized in 1911, national forests .previously having been set aside
only from the western public domain. Prior to 1933, however, the
Federal acquisition of forest lands never exceeded 550,000 acres in
any one year. The total area approved for purchase was only 4,727,-
680 acres in the first 22 years of the program. In 1933 Congress
authorized accelerated activity, and the area acquired in the 3-year
period ended June 30, 1936, exceeded 11,400,000 acres. The acquisi-
tions in the last fiscal year aggregated 2,998,060 acres. Besides add-
ing to the system of federally owned and managed national forests
this accelerated program assured county governments of future reve-
nue from lands that might otherwise have been tax-delinquent, and
harmonized with other aspects of the national agricultural policy.
The national forest system now covers more than 170,000,000 acres
in 37 States and 2 Territories.
Advantages resulting from the Federal ownership and multiple-
use management of forest lands are substantial and varied. They
include protection to watersheds, conservation of merchantable tim-
ber, scientific management of more than 83,000,000 acres of livestock
range, preservation of wildlife, particularly big game and fish, pro-
vision of recreational facilities, and soil and water conservation, with
resulting benefit to power development and irrigation. They afford
innumerable opportunities for recreation; more than 17,000,000 per-
sons visited the forests last year for rest and relaxation. Adminis-
tered by the Forest Service under a system of coordinated use, our
national-forest resources furnish support directly to more than
1,000,000 persons. Modern forestry thus includes more than pro-
ducing continuous crops of timber. It comprises the planned man-
agement of forest, range, and wild lands, and of their many re-
sources; it has to do with conservation through the use. of organic
resources and services in the interest of general welfare.
Forest Protection and Flood Control
How important it is to protect forest, range, and other vegetative
cover so as to retard the water run-off and prevent erosion becomes
evident when floods occur. For example, Pickens, Frankish, and San
Dimas are mountain canyons opening out into fertile valleys of south-
ern California. Fire denuded 5,000 acres in Pickens Canyon in 1933.
Fire similarly swept Frankish Canyon in 1935. Fire did not visit
San Dimas Canyon. On New Year s Day 1934 a flood swept out of
Pickens Canyon, destroyed 200 homes, and killed 34 persons. Though
the same storm hit nearby San Dimas Canyon, it caused no flood there.
This year in January and February floods swept out of Frankish
Canyon through the cities of Upland and San Bernardino. Though
the same storm struck the unbumed San Dimas Canyon, it did not
precipitate a flood there.
Near Centerville, Utah, in 1930 overgrazing was the primary cause
of a flood which wrecked homes and buried orchard lands under soil,
rock, and debris. There was no flood from a nearby watershed that
had been properly grazed. Floods come less frequently and have
lower crests where a vigorous vegetative cover remains.
THE YEAR IN AGRICULTURE 87
Reservoirs arid distributing systems that carry water to some
20,000,000 irrigated acres had a value in 1930, according to the census,
of more than $1,000,000,000. Many billions have been spent for down-
stream engineering to control floods that start with small streams and
additional sums for removing silt from navigable waterways. The
Federal Government has incurred most of this expense. Yet it has
invested less than $70,000,000 to purchase lands where floods and ero-
sion begin, and less than $14,000,000 for replanting denuded forest
and range lands. One of the best and cheapest ways to prevent soil
erosion and combat the danger of floods is to reclothe denuded slopes
with forest and other vegetative cover. In dealing with the flood
problem, prevention is better than cure.
As a flood-prevention measure, the Federal acquisition of 81 mil-
lion acres of lands on important watersheds in 27 States east of the
Rocky Mountains has been recommended. Such lands should be
protectedj revegetated where necessary, and administered as parts of
our existing national forests. The Forest Service has outlined an
expanded program and recommended it to Congress. Preventive
measures in foothills and mountains will help to conserve investments
already made in downstream engineering. Without such preventive
measures the work downstream may not have much effect.
In the fall of 1934, following the great drought of that year, the
Forest Service began to plan shelterbelts in the Great Plains. Such
shelterbelts serve as barriers against soil drying and wind erosion.
They help to catch and retain snow, and to delay the surface run-off.
The shelterbelt planting was not started until the problem had been
thoroughly studied, surveys made of existing shelterbelts, and analy-
sis completed of 25 years' experimental work by Federal bureaus and
State agricultural colleges. By agreement with farmers, the Forest
Service planted about 7,000 acres in the spring of 1935. This year
it planted nearly 24,000 acres, using 23,,000,000 trees in the work.
Examinations in June of all the plantings revealed an average sur-
vival of 81 percent, a highly satisfactory figure for any forest-plant-
ing operation. However, Congress decided to discontinue the Plains
shelterbelt project and appropriated $170,000 to conclude the work
and to dispose of the trees still remaining in the nurseries.
Report on Range Resources
In response to Senate Resolution 289 (74th Cong., 2d sess.), this
Department made a special report on the original and present con-
dition of our range resources. The report was prepared by the
Forest Service. As required by the resolution, it dealt with the fac-
tors that have led to the present condition of the range, with the
social and economic importance of range use and conservation, and
with methods for restoring its productivity. Various Federal and
State agencies furnished data for the report.
The western range is much larger and more important to the
national welfare than most people realize. It includes some 728
million acres, or nearly 40 percent of the total land area of the
country. It is the mainstay of a 4-billion-dollar western livestock
industry, and includes four-fifths of the principal water-yielding
areas on the watersheds of major western streams. Low precipita-
88 YEARBOOK, 1937
tion makes water the limiting factor in nearly all western develop-
ment.
In the range country in 1930, according to the census, there were
775,745 farm units and nearly 400,000,000 acres of land in farms.
Normally these farms grow 35 percent of the feed for western live-
stock. Except for highly specialized crop farming, mostly on irri-
gated land, western agriculture is primarily an integration of range-
livestock grazing and crop farming.
Forage depletion for the entire range area averages more than 50
percent — the result of a few decades of livestock grazing. Kange
depletion on the public domain and grazing districts averages 67
percent; on private lands about 50 percent. Seventy -six percent of
the area is still on the downgrade.. No less than 589 million acres of
range land is eroding more or less seriously, reducing soil produc-
tivity and impairing watershed services. Three-fifths of this area
is adding to the silt load of major western streams. An outstanding
cause of range depletion has been excessive stocking. Some 17.3
million animal units are now grazed on ranges which it is estimated
can carry only 10.8 million. . •
Severe recurrent drought has contributed to this overstocking.
Stockmen have been forced to damage the range, in order to meet
their immediate obligations. Unsuitable land laws have made the
range a bewildering mosaic of different kinds of ownerships and of
uneconomic units. Most spectacular among the maladjustments of
range-land use has been the attempt to use more than 50 million
acres for dry-land farming. About half of this area, ruined for
forage production for years to come, has already been abandoned for
cultivation.
The national forests furnish indispensable summer range. The
83 million acres grazed by domestic livestock has improved so that
it is now depleted only 30 percent; important water-yielding areas
on national forests are being afforded proper watershed protection
and it has been necessary to exclude livestock from only a compara-
tively small area. Kesearch carried on by the Forest Service is show-
ing how to manage range lands for stable forage and livestock pro-
duction, how to reseed severely overgrazed range and abandoned
dry farms in the range area, and how to coordinate grazing use with
erosion prevention, flood control, and water delivery, tree reproduc-
tion, wildlife, and recreation.
PLANT RESEARCH
Excellent results continue to be secured with the two outstanding
varieties of upland cotton introduced and developed by the Bureau of
Plant Industry. These varieties are Acala and Lone Star. These two
cottons, with the strains and varieties developed from them, are now
annually planted on more than 1,000,000 acres in the Cotton Belt,
distributed from Georgia to California. Practically the entire upland
cotton acreage in the irrigated valleys of the Southwestern States —
Texas, New Mexico, Arizona, and California — is planted to Acala.
Because of its productiveness and superior quality of fiber, Acala has
become outstandingly popular with growers in parts of Oklahoma and
Arkansas, and in test plantings conducted for several years at State
THE YEAR IN AGRICULTURE 89
and Federal stations in Texas, Acala has been shown to be especially
well adapted to the great blackland soil area of that State.
One of the outstanding results of the past year's work concerns the
Hopi cotton, a small-boll type grown, probably for centuries, by the
Hopi Indians in northern Arizona. This cotton has a staple only
thirteen-sixteenths of an inch long, but fiber studies and spinning testa
conducted by the Bureau of Agricultural Economics show that it
approaches sea island in fineness and produces a yarn as strong as that
made from l%2-inch upland cottons. The 1%-inch fiber from a first-
generation cross between Acala and Hopi produced a yarn as strong as
that derived from 1%-inch upland cotton.
Interest in sea-island cotton has greatly increased, both among
former growers and among manufacturers desiring this finest of the
world's staples for special textile purposes. In spite of the many
hazards of production under weevil conditions in the Southeastern
States, about 700 acres were planted in 1935 in northern Florida.
Seed for this acreage was the increase from a small reserve stock
furnished by the Bureau in 1934, through the Florida Extension
Service, to a few growers for experimental demonstrations. Only 15
bales were produced on the 175 acres planted in 1934, but 170 bales
were produced on the 700 acres planted in 1935, and sold at prices
ranging from 25 to 28 cents a pound. As a result of the more favor-
able returns in 1935, about 4,000 acres were planted in northern
Florida and southeastern Georgia in 1936.
The need for developing earlier and more prolific strains of sea
island or a substitute for this cotton better adapted to present condi-
tions has become acute. Special studies are being made, therefore, of
hybrids between sea island and outstanding upland long-staple va-
rieties to find a type combining the long, silky quality of sea-island
fiber with the larger bolls and earlier maturity of upland. Approxi-
mately 8,000 hybrids were made in 1935, about 3,000 of these being sea
island crossed on upland and 5,000 upland crossed on sea island. A
system of convergent crosses, in which hybrids are back-crossed to
one or both parents, is being used in an effort to establish pure strains
having the desired combinations of fiber quality and plant char-
acteristics.
Among the extra-staple upland cottons showing special promise as
a substitute for sea island is a selection out of the Tidewater variety
developed by a former sea-island breeder near Charleston, S. O, in
cooperation with specialists of the Bureau. The new strain is much
more productive than sea island, has bolls about twice the size, and
produces a fine quality of fiber 1% inches long. The stock is being
further selected and used in the hybridization work with sea island.
Improved strains of Meade, an early upland variety, with fiber
similar to sea island in length and quality, are also being developed
for use in the studies of extra-staple cottons adapted to production
in the Southeastern States.
The most important result in Egyptian- type cotton breeding during
the past year is the establishment in commercial production of the
SxP variety, derived from a cross between Sakel, the longest in staple
of the Egyptian varieties, and the Pima variety of Arizona. Ap-
proximately 1,700 acres of SxP were grown in the Salt River Valley
138904°— 37 7 ++
90 YEARBOOK, 1937
in 1935, and the yields were so satisfactory and the market for the
product was so active that the demand for planting seed in 1936
greatly exceeded the supply. Some 10,000 acres of this variety are
being grown in 1936 in the Salt River Valley and neighboring dis-
tricts. Production on this scale should determine definitely the posi-
tion of this cotton in the markets as compared with that of Pima.
If SxP can be substituted satisfactorily for Sakel cotton, large quan-
tities of which are imported annually into the United States, a con-
siderable expansion of the acreage of Egyptian-type cotton in the
Southwest would be likely to result, and increased production should
place the American-Egyptian industry upon a more stable basis.
Grains
The stem rust epidemic of 193S was perhaps as severe as or even
more so than those of 1904 or 1916. Late seeding in the spring wheat
belt, delayed. maturity of winter wheat in Kansas and Nebraska fol-
lowing late germination due to a dry fall and winter, a rank growth
of wheat late in the season, unusually favorable conditions for the
development of the rust, and an abundance of inoculum from the
wheat fields of Texas, combined to produce the most widespread
epidemic in the history of the Great Plains. The loss in North
Dakota alone has been estimated at more than $100,000,000 and losses
were proportionately as great in South Dakota and Minnesota. The
winter wheat crop also suffered though not to so great an extent.
The Thatcher variety of wheat, produced as a result of research
by this Department and the Minnesota Agricultural Experiment
Station and distributed to farmers last year, withstood the epidemic
remarkably well. Nominal damage only was suffered by this va-
riety as compared with complete or nearly complete failure for the
Marquis variety under similar conditions. Ceres, which is somewhat
resistant to rust, was also severely injured, though not to so great
an extent as Marquis. Thatcher has proved acceptable to the grain
and milling trade and popular with farmers. The acreage is being
rapidly increased.
Three other new varieties of wheat, produced as a result of the
cooperative work of the Bureau, have recently been distributed to
farmers. Eex, produced at the Moro and Pendleton, Oreg., field
stations, was first grown commercially in 1934. Several thousand
acres were seeded for the 1936 crop. The chief characteristics which
commend this variety to farmers are its resistance to the principal
races of bunt occurring in the Pacific Northwest, early maturity,
winter hardiness, stiff straw, resistance to shattering, and high
yields. It is recommended principally for the area south of the
Snake River in Washington and Oregon.
Hymar, produced at the Washington Agricultural Experiment Sta-
tion, is also highly resistant to the races of bunt most generally
prevalent in the Pacific Northwest. It is popular with farmers
chiefly because of a relatively high test weight and high relative
yields with favorable conditions with respect to moisture. It is
grown chiefly in the Palouse area of Washington north of the Snake
River.
THE YEAR IN AGRICULTURE 91
The quantity of water in the soil at seeding time is definitely re-
lated to the yield of winter wheat. Recent analysis of soil-moisture
and crop-yield data obtained in experiments extending over a period
of 26 years in the central Great Plains has developed principles by
which the farmer may recognize at seeding time conditions that in-
dicate high probabilities of failure or success and regulate the seeded
acreage accordingly. The depth to which the soil is wet can be
determined by observation, and is a good measure of the quantity
of water in the soil. The prospect of a good crop increases with the
depth to which the soil is wet. When wheat is planted in a dry or
nearly dry soil, the probability of success is extremely low. At
three stations in western Kansas the chances were 71 out of 100 that
the crop would be a failure (4 bushels or less per acre), and there
were only 18 chances in 100 or producing a 10-bushel or better yield.
When the soil was wet to a depth of 3 feet at seeding time, the
chances of failure were reduced to 10 in 100 and the chances of
producing a 10-bushel or better crop were 84 in 100.
When little or no rainfall occurs soon after seeding in soil moist
to a depth of only a few inches, the probability of failure is greatly
increased. When the initial soil moisture is deficient and the pre-
cipitation is low to April 1, it is probable that abandonment of the
crop and the conservation of water in a summer fallow for a future
crop will pay far better than allowing the water to be wasted by the
poor crop and the weeds on the land.
Much of the hazard of winter-wheat production in the central
Great Plains can be avoided by limiting the acreage in years when
wheat must be planted on soil that is not wet to an adequate depth.
In some sections a summer fallow for an entire season may be neces-
sary to store the necessary quantity of water, and in sections with
heavier precipitation cultivation beginning immediately after harvest
may be sufficient in most seasons. In particularly dry seasons no
method of cultivation may be able to provide the necessary protection.
Fifteen varieties of oats, developed by breeding mostly in coopera-
tion with the Iowa, New York, Oregon, and Idaho Agricultural
Experiment Stations, were distributed from 1913 to 1931. These
improved varieties are now grown on 10,000,000 to 15,000,000 acres
annually. Among these varieties Richland and Iogold are highly
resistant to stem rust, and Markton is extremely resistant to smut.
These varieties have been crossed with others resistant to crown rust,
and certain of the hybrid selections from the crosses are resistant to
all three diseases and in addition are very promising in yield.
Eleven corn hybrids developed in cooperation with the Iowa, Illi-
nois, and Indiana Agricultural Experiment Stations were distributed
during the period from 1932 to 1934, inclusive, and were grown on
nearly 115,000 acres in 1935. Each of these hybrids has yielded an
average of 12 to 26 percent more than good local varieties in compara-
tive tests during the last 4 or 5 years. These hybrids also have been
much more resistant to lodging than the open-pollinated varieties with
which they have been compared.
Experiments with newly developed early maturing varieties, such
as Sooner milo, indicate that they may be planted as late as July 1 or
15 in most of the commercial grain sorghum producing areas and still
92 YEARBOOK, 1937
mature a crop of grain. For late planting, certain of these newly
developed varieties are far superior to the ordinary varieties that are
more productive when planted early. Sooner milo has matured and
yielded satisfactorily as far north as South Dakota, and also under
irrigation at Logan, Utah, in the intermountain region.
The root-rot disease attacking milo and darso has been found to be
caused by the organism known as Pythium arrhenomanes Drechs.
This organism occurs in the soil of many localities and attacks corn
and sugarcane and certain varieties of sorghum. This disease can be
controlled by the use of resistant varieties. Resistant strains of milo
have been selected bjr the Kansas Agricultural Experiment Station in
connection with cooperative studies of the disease. Susceptibility to
the disease is inherited in a simple genetic manner.
The "white-tip" disease of rice has been demonstrated to be caused
by an iron deficiency. The disease is characterized by a loss of chloro-
phyll from the leaf tips and by chlorotic spots in older leaves.
Plants severely affected have dwarfed, twisted culms and twisted
leaves and panicles, a condition that results in a marked reduction
in yield. Some varieties are less susceptible than others. In green-
house experiments the deficiency of iron, which is associated with
an alkaline soil condition, was corrected by applications of calcium
cyanide, sulphur dust, or ammonium sulphate.
Grass and Pasture
Ecological studies in the central and southern Great Plains to
determine the effect of heat and drought on native grasses were
made at eight different stations in this region in cooperation with
the Kansas Agricultural Experiment Station, and the Division of
Dry Land Agriculture, and the Soil Conservation Service of the
Department. Buffalo grass and blue grama constituted more than
90 percent of the total vegetation on all soils except those which
were very sandy. Buffalo grass was more abundant than any other
grass on the heavier soils, but blue grama was found to be adapted
to a much wider range of soils. A large percentage of the native
grasses were killed during the drought in 1933-34. Soil blowing and
overgrazing contributed materially to the damage, but heat and
drought caused much more injury than grazing. As the intensity
of grazing was increased the actual ground cover of buffalo grass de-
creased. Heavy grazing and drought caused more injury to blue
grama than to buffalo grass. Pastures were severely injured by the
drought but surviving plants remained evenly distributed so that
with favorable climatic conditions and proper management recovery
to normal stands should be possible in a few years.
Woolly fingergrass introduced from South Africa was grazed for
the first time at Tifton, Ga., in comparison with other grasses. This
grass, planted vegetatively in 1934 on unfertilized Tifton sandy loam
soil and with an incomplete stand, carried for 21C days three head
of steers with an initial average weight of 443.3 pounds. The aver-
age gain per steer was 340.3 pounds or a daily average gain of 1.58
pounds per head. This was the largest daily gain on any grass
pasture at Tifton, and these steers were in better condition than any
others. Comparable steers on a pasture of carpet grass, Dallis grass,
THE YEAR IN AGRICULTURE 93
lespedeza, and white clover fertilized annually Avith 600 pounds per
acre of complete fertilizer made an average daily gain of 1.40 pounds
per head. Bermuda grass and lespedeza produced an average daily
gain of 1.02 pounds per head, and kndzu was the only type of pasture
at Tif ton on which the daily gains of the steers exceeded those of the
woolly fingergrass pasture, the average for kudzu heing 1.60 pounds.
The introduction of woolly fingergrass has revived hopes of pro-
viding productive pasture on poor upland soils of the Cotton Belt.
It is both palatable and nutritious but, unfortunately, has failed thus
far to produce viable seed. Breeding designed to overcome this
weakness was begun this year.
During the past year, three new lettuce varieties or strains have
been released to the seed trade. One of these varieties released to
seedsmen under the designation Columbia No. 1 is a crisp heading
sort similar in appearance to the New York and is adapted to cul-
ture in the eastern part of the United States. It appears to be
resistant to tipburn and better adapted to eastern conditions than
any strain of the New York type of lettuce previously grown. An-
other variety is a midseason or summer crop, one adapted to the
Salinas-Watsonville section in California and designated as Imperial
847. It appears to be brown blight-resistant. The third variety
of the group is a mildew-resistant strain of the Grand Rapids variety
for greenhouse culture. It has been released under the name Grand
Rapids No. 1. _, _,
Fertilizer Placement
In cooperative tests having to do with the placement of fertilizer
in the soil with reference to the position of the tobacco plant, strik-
ing results were obtained with respect to both the survival of trans-
plants and the final growth and quality of the crop. Perhaps the
most critical period in growing the tobacco crop is that immediately
following transplanting, a good stand and a quick, even start in
growth being highly important. Certain placements of the fertilizer
resulted in a high mortality of plants, so that although the crop was
replanted two to four times perfect stands were never obtained and
the growth of the surviving plants was irregular. Side placements
have produced uniformly good results, whereas mixing the fertilizer
in the band of soil from I to 6 inches in width and depth around
the plant gave poor results. When the fertilizer was placed in a
banc! underneath the plant, the results were unsatisfactory. Where
the fertilizer was drilled in the open furrow and stirred with the
soil and the row then ridged, the results as a rule were good,
although they did not equal those obtained with the side placements.
Split applications of fertilizer, with a portion applied to the side,
usually produced the highest yield and value of crop obtained in the
tests. In comparative tests with standard-strength and high-
analysis mixtures, the results obtained were in close agreement.
On some of the principal cotton-producing soils of the Southeast
the reinforcing of fertilizers with magnesium and calcium neutraliz-
ing agents has rendered fertilizers more effective in the growing of
cotton. When fertilizers are made nonacid-forming, the less costly
soluble organic and inorganic sources of nitrogen may be as effi-
cient on many cotton soils as the .more expensive natural insoluble
94 YEARBOOK, 1937
organic sources of nitrogen and all the fertilizer may be applied at
or in advance of planting on many soils without serious danger of loss
by leaching. The application of such fertilizers at planting tends
to reduce the production cost of cotton when compared with the
system of applying the mixture containing part of the nitrogen at
planting and the remainder as a separate application after the crop
is up. Fundamental work with machine placements of fertilizers to
cotton, in cooperation with the Bureau of Agricultural Engineering,
has shown side placements to be the most satisfactory. Efforts are
being directed toward devising practical and inexpensive means of
accomplishing this placement of fertilizer.
WILDLIFE
With allotments from emergency funds aggregating $8,500,000, the
Bureau of Biological Survey on July 1? 1934, undertook the task of
averting the most serious crisis with which waterfowl in this country
have ever been faced. Of this amount, $8,100,000 has been expended,
and the balance has reverted to the Treasury.
The most protracted drought in our history, drainage operations,
and attempts to reclaim land for agricultural purposes had combined
to bring about an extremely serious shortage of waterfowl breeding,
resting, feeding, and wintering grounds. This condition, augmented
by an increase in botulism and other waterfowl diseases, large-scale
bunting activities, and the toll taken by predatory animals had so
alarmingly reduced the waterfowl population as to forecast extinction
of many species within the space of the next 5 years unless preventive
steps were taken at once.
To save waterfowl and restore them to approximately their former
abundance was and is the primary consideration of the Survey's
activities, but it should not be overlooked that these activities con-
stitute a powerful weapon in the battle toward economic recovery
and reconstruction. This will be evident from consideration of the
following integral parts of the duck-restoration program :
1. Purchasing large areas of submarginal land, which in practically
every case has proved entirely unfit for agricultural usages. The sale
of their land has enabled distressed farmers to move to more desirable
locations and start anew.
2. Employment by the Survey of a large number of men, many of
whom were on relief rolls. This is especially important, since, in the
main, these activities are located in drought-stricken areas that have
been the hardest hit by the depression.
3. The construction of storage dams, marsh embankments, and
other water-impoundment devices in the course of the development
of practically every wildlife refuge. These improvements will con-
serve valuable water resources which are now being dissipated to an
alarming degree. The drought has emphasized the need for the con-
servation of water, and the popularity of the Survey's activities in
the Dakotas, for example, shows that there is great public interest
in this phase of conservation.
4. The propagation and protection of heavy growths of vegetation
for waterfowl food and cover. Such work forms an important part
THE YEAR IN AGRICULTURE 95
of the refuge-development program and helps to repair the damage
which the uncontrolled action of wind and water has inflicted.
Between $800,000,000 and $1,000,000,000 is spent annually for
sportsmen's equipment and outdoor facilities, and a million people
depend wholly or in part upon some aspect of this business for their
livelihood. In addition, there is the fur industry, with an estimated
$500,000,000 annual turn-over in retail trade. The threat to industries
of such proportions obviously merits attention.
The educational and esthetic value of wildlife is important, and
laboratory facilities are being provided on a number of the water-
fowl refuges. The fund of data in the natural sciences will thus be
enriched. The hunting, as well as the observation, of waterfowl
furnishes millions with healthful recreation. On many wildlife
refuges the Survey is developing picnic grounds and bathing facili-
ties for the use of the public.
The total acreage of bird-refuge land actually administered by the
Biological Survey as of February 29, 1936, exclusive of the acreage
of those refuges located in Alaska, Hawaii, and Puerto Rico, and
exclusive also of a large acreage of big-game land on which birds
are also protected, is 2,118,433 acres and includes more than 100
refuges. There are additional areas on which options for purchase
have been approved by the Migratory Bird Conservation Commis-
sion. These areas total some 999,398 acres and include 36 areas that
are now, or soon will be, functioning as waterfowl refuges through
special permits from the owners. Thus it may be said that there are
now under the Bureau's jurisdiction over 3,000,000 acres of bird-
refuge land.
Big-Game Refuges
Two outstanding big-game refuge projects have been inaugurated
under the $6,000,000 appropriation approved June 15, 1935. One of
these provides for the enlargement of the Elk Eefuge in Teton
County, near Jackson, Wyo., to take care of the great bulk of the elk
of the southern Yellowstone herd which winter in the Jackson Hole
country. This project involves the acquisition of 20,000 acres to be
administered in connection with the 4,500 acres already owned and
operated at that point. Roughly, the area includes the land lying
north of Jackson, east of the Jackson-Moran Highway, south of the
Gros Ventre Riyer, and west of the boundaries of the Teton National
Forest. The elimination of private interests from this area and the
restoration of grazing therein will provide an abundance of winter
feed for the elk. This project is very important.
The other project is known as the Hart Mountain Antelope Range,
in Lake County^ southeastern Oregon. It has been established by
Executive order in connection with the organization of grazing dis-
tricts under the Taylor Act. The_ purchase of some 25,000 acres of
privately owned lands has been initiated under the 1935 appropriation
above mentioned.
Other pending projects for the designation of ancestral game
ranges have been agreed upon in connection with the grazing districts
being organized under the Taylor Act.
Improvement of big-game refuges by C. C. C. camps has continued
at the National Bison Range, Mont.; the Niobrara Game Preserve,
96 YEARBOOK, 1937
Nebr. ; the Charles Sheldon Antelope Refuge, Nev. ; and the Wichita
Mountains Wildlife Refuge, OHa.
Federal authority over migratory birds will be reinforced and
extended by an act of Congress approved June 20 to give effect to
the convention between the United States and Mexico for the protec-
tion of migratory birds and game mammals. The United States
Senate on April 30 consented to the ratification of the treaty. Mexico
has not yet ratified the treaty. It will take effect on the exchange
of ratifications. Federal authority over migratory birds has hereto-
fore depended on the Migratory Bird Treaty with Great Britain.
The new treaty reinforces this authority by providing for a dual
basis for the Federal regulations conserving ducks, geese, and other
migrants.
With the signing of an agreement by State agencies in Ohio, nine
States are now cooperating with the Biological Survey in investiga-
tions to learn how to increase, maintain, and use wildlife resources
and to show on trial areas how research results can be applied. The
cooperating States are Alabama, Connecticut, Iowa, Maine, Ohio,
Oregon, Texas, Utah, and Virginia. These were selected for research
on a regional basis and to avoid duplication of effort. Each State
program is arranged so that the information obtained may ba
applied in a large area.
AGRICULTURAL ENGINEERING
The best regulation and use of the waters of at least 11 of the
Western States depend upon reliable forecasts of stream flow. Ad-
vance knowledge of stream flow is indispensable to the proper opera-
tion of irrigation, hydroelectric, and flood-protection works. In the
making of such forecasts, however, adequate snow surveys are neces-
sary, and snow surveying has not yet reached the required propor-
tions. Accordingly, the Bureau of Agricultural Engineering, in
cooperation with other Federal and State agencies, is planning several
hundred new snow courses for survey during the winter of 1936-37.
This undertaking will extend the snow-survey work into areas not
now served.
This Bureau has had the responsibility of coordinating, standardiz-
ing, and extending the snow-survey work of various agencies. It
issued forecasts of the 1936 season's water supply for the greater
parts of California, Oregon, Nevada, Idaho, Utah, Wyoming, and
Colorado shortly after April 1936. These forecasts indicated that
most of the streams would yield 100 to 125 percent of the normal
supply and that the run-off would equal the highest recorded in the
last 10 years. With this assurance, irrigators prepared to plant all
the area that had heretofore been irrigated.
However, the unusually warm spring resulted in a very early and
very heavy run-off. In areas having inadequate storage facilities
much water ran to waste; and in some areas little irrigation water
was left for late-season needs. Warned against planting late crops,
farmers adjusted their cropping programs and avoided certain loss.
Where long snow-survey records were available, it was possible to
distribute the water among the storage reservoirs in such manner as
to effect the greatest economy in its utilization.
THE YEAR IN AGRICULTURE 97
The net safe yield of water for irrigation from western watersheds
depends upon reservoir storage. Evaporation from lakes and reser-
voirs results, however, in a material loss. This loss is largely un-
avoidable, but knowledge of its magnitude and of the factors that
influence evaporation helps in devising means for reducing the loss,
in estimating the available reservoir supply, and in determining the
feasibility of reservoir-construction projects. It is useful also in
planning irrigation, municipal water supply, and hydroelectric proj-
ects. The data collected by the Bureau provide the basis for estimat-
ing the evaporation losses from the surfaces of stored water and from
water transported long distances in open conduits.
The best use of water requires an understanding of soil character-
istics, particularly those related to the absorption and retention of
water. Studies of the rate of movement of capillary moisture have
high practical value in determining soil-moisture conditions, with or
without irrigation. Studies of the infiltration of water into the soil
indicate what types of soils can best be irrigated, and how land
should be prepared for irrigation. Research in the Bureau of Agri-
cultural Engineering is throwing new light on these problems.
Irrigation to protect high-value crops against drought is receiving
increased attention in the Eastern States. Where suflicient water can
be had at reasonable cost, the practice is profitable in growing fruits
and vegetables. In the spring of 1936 irrigated strawberries on the
Eastern Shore in Maryland produced an excellent crop of high-grade
berries. The increased income this year practically paid the cost of
installing the irrigation equipment. Adjacent unirrigated fields, be-
cause of drought, produced no marketable berries. Profitable results
from irrigating fruits and vegetables were reported also from Flor-
ida, Michigan, New Jersey, Ohio, Virginia, and West Virginia. But
results from the irrigation of general field crops in the East do not as
a rule justify the expense.
Common tillage practices in the production of cotton can readily
be modified so as to increase the yield and lower the cost of pro-
duction on at least one soil type — Greenville sandy loam. This has
been discovered in tillage experiments carried on for 5 years at
Prattville, Ala. The methods and the tools used in tillage influence
both fiber length and yield. Operations repeated each year with
implements that improve or injure the soil structure have a cumula-
tive effect on the crop. The depth and the method of turning under
green manure crops also influence the yield of cotton on this soil.
Improved Farm Equipment
New or improved equipment is being put out by farm-machinery
manufacturers partly as a result of investigations by Department
engineers. This machinery includes (1) fertilizer distributors that
place the fertilizer, during the planting operation, at the proper dis-
tance to the side and below the seed to be of greatest benefit to the
crop ; (2) the variable-depth cotton planter, which eliminates the
necessity for replanting except under extraordinarily unfavorable
weather conditions; and (3) a basin-forming attachment for the
lister when used in planting corn, designed to form dams at short
98 YEARBOOK, 1937
intervals in the lister furrows to conserve moisture by holding rain-
fall and to prevent or reduce erosion by water and by wind.
Farm-machinery sales have increased. Information received by
the Bureau of Agricultural Engineering indicates that the value of
all the equipment sold in the United States by manufacturers in
1935 was $325,566,909, as compared with $248,979,523 in 1931. Sales
during 1936 will probably exceed $400,000,000. Much of the increase
will be due to the sale of newer types of equipment, such as the
general-purpose tractor on pneumatic tires, and the small combined
harvester-thresher. It is estimated that no fewer than 7,500 com-
bines operated from the tractor by power take-off and mounted on
pneumatic tires were used this year in the Corn Belt and the South-
ern States. These machines harvest a variety of crops satisfactorily,
particularly soybeans and small grain. The power take-off, which of
course does away with the need for an engine on the combine, re-
duces the cost of the machine greatly; and the pneumatic tires make
lighter construction possible. Though the small machines have a
narrower cut than the machines formerly in common use, the rate of
harvesting is not proportionately lower, because the smaller machines
can be pulled at higher speeds.
Tests conducted at the Department's cotton-ginning laboratory at
Stoneville, Miss., have attracted wide interest. Many ginners are
modernizing their gins and following the recommended methods. In
the 1935-36 ginning season 200 seed-cotton driers, built on a principle
patented by Department engineers, conditioned about one-third or a
million bales of damp cotton for ginning. About 300 such driers may
be in operation in the 1936-37 ginning season.
In buildings for the storage of fruits and vegetables in commercial
quantities, especially in cold climates, the control of temperature and
humidity (or air-conditioning) is important not only for the safe and
economical holding of the crop but for the prevention of damage to
the buildings. Investigations of potato storage by this Department
in cooperation with the Maine Agricultural Experiment Station have
developed an improved method of obtaining the desired air condi-
tions. These methods take advantage of the well-known fact that
moist air coming in contact with a cold surface deposits moisture,
and in so doing liberates about 1,000 British thermal units of heat
per pound of moisture condensed. In this way the walls of the
storage house are dampproofed and the ceiling is insulated more
than the walls, so that high humidities to aid in Keeping the potatoes
in good condition can be held without damage to the building. In
cold weather excess moisture given off by the potatoes is drained
away as water, with much less loss of heat from the building than
if it were carried away as vapor by ventilation. Heating and venti-
lation during cold weather are reduced to the minimum and loss of
weight by the potatoes is lessened. The same principle is applicable
to the storage of other vegetables and fruits. With some modification
it may be useful in buildings for livestock and for other purposes.
Improvement of Farm Homes
The improvement of farm homes remains one of the unaccomplished
tasks of agriculture. Observations in many parts of the country indi-
THE YEAR IN AGRICULTURE 99
cate that comparatively few farm families have as yet found it
practicable to provide themselves with modern homes either through
new construction or by modernizing the old dwellings. Sooner or
later there must be a tremendous volume of farm-home improvement
and new construction. Therefore this Department, in cooperation
with the State Universities of Wisconsin and Georgia, is gathering
facts about the comfort and service provided by various types of farm-
houses found in the North and in the South. One phase of the in-
vestigation deals especially with the factors in house design that con-
tribute to comfort in hot weather. The results should aid materially
in the development of improved designs.
GRADING AND STANDARDIZATION
A new principle entered the grading and standardization work of
the Department this year. It was the use of the referendum to de-
cide whether or not a group should have mandatory inspection based
on Federal standards for market quality and condition.
This new development was provided for in the Tobacco Inspection
Act, signed in August 1935. Permissive inspection, which began in
1929, has demonstrated the feasibility and practical value of tobacco
inspection based on standard grades. Several referenda indicated
that tobacco growers in large numbers want mandatory inspection.
They see in it a means of reducing the costs and improving the
efficiency of marketing and distribution.
The tobacco-inspection service has for its object the certification
of the grade on each lot of tobacco offered for sale at auction. It is
designed to overcome the average producer's lack of technical knowl-
edge of the qualities and values of his tobacco and to improve the
general technique of marketing the crop. It is coupled with a price-
reporting service that gives the current average prices for the vari-.
ous grades. These two services enable the grower to have, at the
time he sells his tobacco, a competent and disinterested judgment on
the quality and approximate market value of his offering.
As a result of favorable votes in several referenda, mandatory
inspection service has been ordered for 18 tobacco markets, and an-
other market has voted favorably on the matter and will soon be
designated. The law, however, has been challenged in the courts,
and a temporary injunction issued, which for the time being stops
the grading of tobacco on three designated markets in South
Carolina.
The first official inspection service known to have been provided
for any agricultural commodity was a tobacco-inspection service. It
was passed by the Virginia House of Burgesses in 1619. Since then
much legislation pertaining to tobacco inspection and to other phases
of production and commerce in tobacco has been enacted. However,
the Tobacco-Inspection Act is the first piece of national legislation
providing for tobacco inspection that has had for its primary object
the protection of the producer's rights and interests when he offers
his tobacco for sale. The first State legislation of a similar character
was enacted by Virginia in 1933. It related to fire-cured tobacco,
type 21, which is produced in a group of counties south of the James
River.
100 YEARBOOK, 1937
An educational program has been started in connection with the
mandatory tobacco inspection and the market-news service to promote
improved methods of sorting tobacco and preparing it for market.
This program is limited at present, but it has met with an encouraging
response from county agents, agricultural teachers, farmers, and the
tobacco trade.
Permissive Federal Standards
There has been for many years an extensive use of Federal stand-
ards on a purely permissive basis. Along with the use of mandatory
Federal standards for cotton and grain under certain interstate mar-
keting conditions, the voluntary use of optional Federal standards has
developed. Progress has been particularly noteworthy in the fruit
and vegetable industry. Ten years ago the Federal Inspection Serv-
ice inspected 198,075 cars. Last year it inspected 395,250 cars. In
the concurrent development of the two methods the compulsory and
voluntary use of Federal standards have promoted each other. This
year marks the first meeting of compulsory and voluntary action in
the case of a single commodity.
Extensively revised standards were recently promulgated for grain
and cotton to meet the needs of changing production and marketing
practices and to embody new knowledge.
The United States standards for cotton also serve as the universal
standards for American cotton. Accordingly representatives of nine
principal European organizations were consulted in the revision of
the standards. Leading representatives of American organizations of
producers, manufacturers, and shippers were consulted also. The
revised standards became effective in August 1936. They are more
representative than the former standards of the characteristics of the
cotton now produced and are more readily used. The number of
grades is reduced from 37 to 32, and the number of standard boxes
from 25 to 13.
Along with the whole question of what constitutes quality in cotton,
methods are being studied for the further measurement of quality
New techniques are being devised and tested. They may permit
further improvement in the standards.
The revised grain standards were drawn to meet changes in mer-
chandizing, milling, other processing, and baking. All groups
interested m grain marketing from the farm to the export wharf
were urged to examine and test the revised standards before they
were promulgated. Somewhat less significant, but not less useful,
revisions are being made in the permissive standards from time
to time.
Farm products inevitably include wide ranges in quality. Stand-
ards must change with significant changes in production practices,
bometimes preferences and requirements of consumers vary decidedly
in different markets. Changes in industrial technique or in methods
oi marketing may change the importance of certain quality fac-
tors or quality standards. New knowledge of nutritive values may
upset previously formulated specifications of desirability, and new
techniques for the measurements of quality may make improve-
ments possible. It is, therefore, necessary to revise the standards
periodically.
THE YEAR IN AGRICULTURE 101
Improvements in Standardization
The first Federal standards were largely empirical, but in expert
hands they served. As a basis for transactions between distant
points, for a common trade language between farmers, dealers, and
consumers, for market quotations, for price and market comparisons,
and for agricultural financing and credit, they answered many vital
wants. But research and experimentation in the Department stead-
ily improved the standards and the methods of applying them.
Methods, instruments, and other apparatus were adapted to specific
ends. Many public-service patents have been obtained for appa-
ratus designed especially for grain standardization and inspection,
and for other agricultural commodities. This year saw the conclu-
sion of an exhaustive practical test of a new grain-sieving device
known as the Federal dockage tester, the making of new conversion
charts for use with electric meters in determining the moisture
content of Argentine flint corn and several other grains, and an
improved refractometric method for determining the oil content of
flaxseed. This method requires only a half hour instead of the 16 to
24 hours formerly required. In commodity grading much still re-
mains subject to human judgment and skill, particularly in regard to
such factors as flavor, body, and color in butter. But accurate meas-
urements, through mechanical or chemical means, are steadily re-
placing the earlier empirical knowledge and ways.
These techniques are the results of laboratory and economic re-
search supplemented by practical observation. The studies are fre-
quently intricate but the resulting tests must be simple and prac-
tical. As a general rule, the standards reflect the normal spreads in
the market value of a commodity. The steps between grades corre-
late fairly closely with the price differentials that prevail in the mar-
ket. Research is providing more precise measures of the price sig-
nificance of separate quality factors. Some quality factors that
affect prices, however, may not yield to statistical measurements, and
it is necessary then to rely on observation and judgment.
The relationship between the grades and market price differen-
tials does not remain constant necessarily. Price spreads between
grades of a product frequently reflect the proportions of the product
that fall within each of the grades. There are other influences.
Buyers' opinions as to value do not always correspond to intrinsic
value. Before the Federal standards were adopted, for instance,
"pea-green color" was the quality factor in alfalfa hay that com-
manded a premium. Research disclosed that the feed value of alfalfa
hay correlates more closely with its leanness. Then the factor of
leafmess was given greater emphasis in the standards. Steadily in-
creasing premiums paid for leafy as compared with pea-green alfalfa
apparently reflect the influence of the revised standards. Present
studies give special consideration to the carotene or provitamin
content of hay.
Naturally, standards have limitations. They cannot meet all re-
quirements. Some believe they are too general, and do not ade-
quately measure variations in quality. This difficulty often lies in
the products. As research yields more accurate measures of quality
factors, the descriptive standards will become more precise.
102 YEARBOOK, 1937
Sometimes the margin recognized between the upper and lower
limits of some grades may seem to be too wide and may not ade-
quately reflect qualities peculiar to the products of various regions.
But the national grades have to serve the national industry. It is
impracticable to narrow them so as to cover all gradations in quality.
Eegional characteristics that have market value may be covered in
additional local notations. It may prove desirable for some com-
modities to have different sets of standards for different stages in
marketing. Special consumer grades may sometimes be practicable for
retail use. _
Consumer Interest Awakeneb
In fact, an outstanding recent development has been the awaken-
ing of consumer interest in commodity standardization. Led by
informed and organized groups, the consumers' voice increasingly
demands grade specifications that can be used in making household
purchases, and truthful and informative labeling based on these
grades. Consumers have a right to know what they are buying. The
Federal standards for meat are adapted to consumer needs, and the
Federal labeling of meats by grade has had excellent consumer re-
sponse. Beginning in 1927, in the first full year of this service,
28,000,000 pounds of meat were officially graded and stamped. Dur-
ing the last fiscal year 423,000,000 pounds were so graded and
stamped. Originally only beef was stamped; now beef, lamb, mut-
ton, sausage, and certain other meat products are included. Seattle
in 1934 passed an ordinance requiring that all .beef, lamb, and mutton
sold within the city limits be graded and stamped. Schenectady,
N. Y., has passed a similar ordinance.
The labeling of canned fruits and vegetables according to grade
has made rapid progress. The movement has strong consumer sup-
port, and strong support among certain groups in the canning trade.
One large chain-store organization is using Federal grade designa-
tions on its pack of several fruits and vegetables and giving them
national distribution. National advertisers, however, are reluctant
to adopt uniform grade labeling. They fear that their brands will
lose prestige. But brands do not give consumers the information
they want. There is no reason, moreover, why both the brand name
and the grade designation cannot be used on labels. The Federal
standards for butter, eggs, and certain kinds of poultry are suitable
for consumer use. Labels based on these grades are coming into
retail use.
Possibly the next line of decisive progress will be in the greater
use of Federal grades by consumers. That may require the develop-
ment of speciaigrade specifications or descriptions.
HOME ECONOMICS
Letters that pour into the Bureau of Home Economics indicate that
the American public has turned "consumer conscious." Men as
well as women are asking daily for help in planning budgets. They
want to know how to get the most for their money, no matter how
adequate or how limited their income. The economic situation of
recent years has made families at all levels of living conscious of
the need to budget their resources, to buy wisely, and to save. This
THE YEAR IN AGRICULTURE 103
is true of heads of families and of single men and women whose
letters indicate a good educational background, but it is equally
true of those whose letters indicate that their educational oppor-
tunities have been meager. It is true of families who are trying
to adjust, to the budgeting of incomes of $5,000 to $6,000 a year when
they formerly were distributing very much larger amounts for
family needs, and also true of families who are trying to make ends
meet when the total resources consist of less than $60 a month from
work relief.
The solution of such problems must come in part through study
of the spending habits of American families. Yet there has never
been a comprehensive study of American consumption habits and
needs. For this reason the Bureau of Home Economics is now
cooperating in such a study, which has been launched under the
Works Progress Administration.
When the Emergency Relief Appropriation Act of 1935 was passed
proposals to undertake a study of consumption habits as a Federal
Works project were submitted jointly by the National Resources Com-
mittee, the Bureau of Home Economics, and the Bureau of Labor
Statistics, the latter Bureaus constituting the administrative agencies.
The study of consumer purchases was approved by the Works Prog-
ress Administration in December 1935. Methods for collecting, edit-
ing, and tabulating the necessary data were developed cooperatively
by the Bureau of Home Economics, the Bureau of Labor Statistics,
the National Resources Committee, the Central Statistical Board, and
the Works Progress Administration.
The work of selecting a staff and of setting up regional and local
offices in 27 States was begun in a preliminary way in January 1936.
The field work, begun shortly thereafter, is now nearing completion,
and statistical pools are engaged in tabulating the data. Information
has been collected from about 50,000 families interested in cooperating
to the extent of giving facts about their income, about the age and
occupation of their members, and about the commodities and services
they buy. About half of these families have given more detailed
information on their expenditures for housing, food, clothing, trans-
portation, medical care, and various other types of goods and services,
and on their savings. In addition, from a smaller number of families,
detailed information has been obtained on the kinds and quantities of
food, household equipment, furnishings, and clothing procured.
Families living on farms, in villages, and in small city areas are
cooperating with the Bureau of Home Economics. City families are
cooperating with the Bureau of Labor Statistics. When all of the
facts are consolidated we shall know for the first time what typical
American families actually buy and what kind of living they get.
The cooperating families represent different occupations and family
incomes ranging from $250 up to $5,000 or more a year. The facts
will typify living conditions in different sections and will show varia-
tions due to rural and city living.
Not only will the families profit who assist in the study but the
findings will be valuable to all families who want guidance in
budgeting. Consumers' wants should eventually be met more satis-
factorily because the information, when summarized and interpreted,
104 YEARBOOK, 1937
will help farmers and manufacturers to produce with less waste.
Merchants will have a better guide to probable changes in consumer
demand. The United States Chamber of Commerce requested such
a guide a few years ago.
The social value of the study will be important. The public, and
local, State, and Federal agencies concerned with public health and
general welfare, will have new facts to show the prevailing levels of
living in this country and to indicate the need for betterment.
Value of Diet Statistics
Facts about what the public eats are indispensable in planning farm
production and distribution. Such facts also have an important bear-
ing on education in dietary problems. The general well-being of a
people is largely dependent on the adequacy of their diet. Many fam-
ilies who now fail to get a satisfactory diet can have a satisfactory diet
for the same expenditure if they will consider both nutritive value and
cost in choosing their foods. In order to help them the Bureau of
Home Economics prepared Farmers' Bulletin 1757, Diets to Fit the
Family Income. This bulletin discusses scientific principles of nutri-
tion and food economics in nontechnical language.
During the past year, the Bureau analyzed the kinds and quantities
of food purchased and the nutritive value of the diets of wage-
earning families. The necessary records were collected by the Bu-
reau of Labor Statistics, in conjunction with a study of the dis-
bursements of families of wage earners and low-salaried clerical
workers. About 2,500 records became available for this analysis.
As a result, extensive figures will soon be available on the kinds and
quantities of food purchased by city wage-earner families in different
sections of the country, at different seasons of the year, and at dif-
ferent levels of expenditure.
The diets have been analyzed for their nutritive content and ap-
praised in the light of dietary standards. A preliminary report of
the work appeared in the July 1936 issue of the Monthly Labor Re-
view. This report, with an analysis of the diets of nonf arm American
families as shown by studies made during the last 20 years, was
sent to the International Labour Office and to the health committee
of the League of Nations in December 1935.
The quantity of all food purchased (on a per-capita basis) in-
creases, as one would expect, with the expenditure for food. This
was shown by classifying into groups the diets of all families
studied, by $32 intervals adjusted to 1935 price levels. From a level
of expense for food of $32 to $65 per capita per year to a level of
expense for food of $258 to $290 per capita per year, the increase in
weight of food per capita as shown by this classification was almost
threefold. Naturally, however, the percentage increase from one
level to another was much greater at the lower than at the upper
levels of expenditure.
For some food groups, such as the grain products, purchases in-
crease relatively little as expenditures increase. Foods from the
cereal grains usually are cheap in relation to their ability to assuage
hunger. Hence, they appear, as might be expected, in generous
amounts in low-cost diets, as well as m expensive diets. The con-
THE YEAR IN AGRICULTURE 105
sumption of milk increases rapidly with increasing expenditures at
the lower levels, but less rapidly after the pint-a-day level of con-
sumption is reached.
With increasing expenditure for food, changes in the quantities
consumed of fruits and vegetables (other than potatoes and dried
legumes) are very striking. The increase from the lowest to the
highest level of expenditure is almost sixfold. Citrus fruits, to-
matoes, and leafy, green, and yellow vegetables comprise about 40
percent of the total in each level of expenditure for food. These
fruits and vegetables are mentioned especially because of their sig-
nificance as sources of vitamins and minerals.
The increase in the consumption of lean meats and fish is almost
threefold between the lowest and highest levels of expenditure, while
the consumption of fatty foods almost doubles. Butter consumption
increases almost five times, but the consumption of other fatty foods
remains almost constant. Butter seems to be used in addition to and
not as a substitute for lard, bacon, salt pork, and other fats and oils.
The fourth of the nonfarm population that spends the most for
food consumes about one-third of the milk, fruits, vegetables (other
than potatoes and dried legumes), meat, fish, and eggs, whereas the
fourth that spends the least for food consumes about one-sixth of
those products. Differences in consumption at different economic
levels in any one region are much more important than differences
between geographical regions at any one level.
Social Implications of the Data
The most frequent level of expenditure for food among the families
from whom dietary records have been taken was found to be that
ranging from $100 to $130 per capita per year (1935 price levels).
About half of the families were spending less than $130 per capita
per year. According to 1935 prices, a minimum-cost adequate diet
could be obtained with careful food selections for just about $130
per capita per year. The inference is that the diet of half the non-
farm population probably fails to provide a desirable margin of
safety over minimum requirements. At the lowest levels of expendi-
ture for food the calorie intake is far below the average for the
population and far below the probable need ; one need not, therefore,
be surprised to find retarded growth in children and undernutrition
in adults.
On the other hand, the figures shown for families spending the
larger amounts for food probably represent quantities available to
the household rather than quantities actually eaten. They include
considerable household waste. Hence the quality of the diets of the
higher-income groups depends on how much and what is wasted.
Calorie for calorie, the food supply purchased by families spending
the largest amounts for food is only slightly higher in proteins,
minerals, and vitamins than the diets of low-income groups. But
if the milk and vegetables and fruits purchased are almost completely
consumed, while waste occurs principally in the fats, sugars, and grain
products, the food actually eaten by the higher-income groups may
be considerably richer in minerals and vitamins than the diets of
low-income groups.
138901°— &7 8
106 YEARBOOK, 193 7
The percentage of the calories purchased in the form of grain
products is much higher in low-income groups than in the higher
income groups; it ranges from more than 40 percent in the lowest
level of food expense studied to somewhat less than 30 percent of the
calories at the highest level. An opposite trend may be observed
for most other groups of foods. The percentage of calories derived
from milk almost doubles as the expenditures for food increases, and
the percentage derived from lean meats, fish, and eggs increases
significantly.
Futher study of these consumer purchases will furnish more au-
thoritative figures on food-consumption habits and on food expendi-
tures. It will show, for example, how food-consumption habits may
vary among families spending the same amounts for food, but repre-
senting different socioeconomic groups. It will also provide figures
on the proportion of the native-white families of each type that
represent different levels of food expenditures.
There is widespread interest in these data, not only from the stand-
point of science and social welfare but also from the standpoint of
the economic implications. The governments of many nations, as
well as international and national bodies of economists, educators, and
others interested in social and economic planning, are giving much
attention to these problems.
COMMODITY EXCHANGE ADMINISTRATION
To improve and protect the means furnished by properly con-
ducted futures-contract markets for the hedging of price risks by
growers, dealers, and processors of essential agricultural products,
the Gram Futures Act of 1922 was strengthened by amendment on
June 15, 1936. It was extended to cover cotton, rice, millfeeds,
butter, eggs, and potatoes, and the short title changed to the Com-
modity Exchange Act.
The principal amendments include the following :
That commission merchants and brokers executing orders for cus-
tomers in a contract market shall register with the Department of
Agriculture and shall keep adequate accounts and records, which
shall be available for official inspection; that copies of all bylaws,
rules, and regulations adopted by contract markets shall be filed
with the Secretary of Agriculture and their books and records be
made available for inspection; that operators of warehouses from
which any commodity is made deliverable on futures contracts shall
keep such records, make such reports, and permit such visitation as
the Secretary of Agriculture shall require ; that when so directed by
the Secretary, each contract market shall provide for a period, after
trading for future delivery in any delivery month has ceased, in
which to make settlement by delivery, such period to be not less than
3 or more than 10 business days ; that each such market shall require
the party making delivery to furnish the party receiving delivery
written notice of the date of delivery at least i day prior thereto;
that deliverable commodity grades must conform to United States
standards, if such standards shall have been officially promulgated;
that receipts of federally licensed warehouses, as such, shall not be
discriminated against in deliveries upon futures contracts.
THE YEAR IN AGRICULTURE 107
Provisions of importance to cooperatives are that no contract mar-
ket shall forbid the payment of patronage dividends by a coopera-
tive association to bona-fide members; that a properly qualified
cooperative association shall not be excluded from membership in
and trading privileges on a contract market unless such exclusion is
authorized after notice and hearing before the Commodity Exchange
Commission, except for failure to meet its obligations with the clear-
inghouse of the exchange; and that cooperative associations of the
federated type are authorized to compensate on a commodity-unit
basis their regional member associations for services rendered, pro-
vided such compensation is distributed as a dividend on capital stock
or as a patronage dividend out of net earnings or surplus of the
federated association.
Special protection has been thrown around the margin moneys of
the customers of futures commission firms. The act requires all
futures commission merchants to treat and deal with all margin
moneys, including securities and property, as belonging to customers.
Such funds must be separately accounted for and may not be com-
mingled with the funds of the commission merchant or used to mar-
gin the trades or contracts or extend the credit of any person other
than the one for whom the same are held.
The danger of excessive trading by individuals or allied groups
is also given special attention. The Commodity Exchange Com-
mission has wide discretion in fixing limits for speculative trading
whenever it appears that such limits are necessary. Ample latitude
for hedging is carefully preserved.
Fraudulent trading is made more hazardous. Criminal penalties
may be imposed for various offenses, such as conducting a bucket
shop, speculative trading in excess of a limit fixed for such transac-
tions, the manipulation of prices} engaging as a futures commis-
sion merchant or floor broker without prior registration, trading
against customers' orders, dealing in privileges, making wash sales
and cross trades, and fictitious trading.
During the past year three cases pending under the Grain Futures
Act of 1922 were dismissed following decision of the Circuit Court
of Appeals of the Seventh Circuit that the law did not apply to
past offenses. This defect in the original law has been remedied in
the amended act, which provides penalties for any person who has
violated the act as well as for any person who is violating the act.
COOPERATIVE EXTENSION WORK
The cooperative agricultural extension system operates in two prin-
cipal fields of service: (1) It mobilizes Federal, State, and county
facilities for helping farm people to solve their ordinary problems
of production and marketing, homemaking, and country-life improve-
ment. (2) In great national emergencies it tackles the resulting
special problems. In the last few years it has taken an active part
in the administration of production-adjustment programs; loans to
farmers on stored crops; drought-relief measures; programs for the
prevention of soil erosion ; programs for debt adjustment and farm-
credit improvement ; and rural rehabilitation and relief.
108 YEARBOOK, 1937
In advancing these programs and activities the extension agents
directly represented the Federal and State agencies. They acted as
advisers and assistants in the organization and educational work,
and functioned also in an administrative capacity in cooperation with
local committeemen and producers' groups or associations. The
county extension offices were the centers where committeemen and
extension agents gave practical help and necessary instructions.
Local committeemen assisted capably in the administration of the
national programs, particularly in dealing with regulations, rulings,
agreements, papers, and essential forms. They relieved extension
agents of much detail work and enabled them to handle more effi-
ciently their larger responsibilities. In many counties local com-
mitteemen handled most of the local routine involved in the national
programs.
Both paid agents and volunteer leaders furthered the educational
features of the extension programs. Without the help of local
volunteer leaders the rural boys' and girls' 4r-H club work would
have suffered. Local le.aders helped also to conduct adult demon-
strations and rural educational meetings. As a result farmers are
coming to understand better how general economic conditions affect
their individual problems. They discuss the effects of tariffs, quotas,
price policies, price levels, currency measures, monetary systems,
credit, taxation, and land-use policies. They are learning more
about the interdependence of town and country and about the limita-
tions of individual self-sufficiency. They are grasping the logic of
group action in meeting emergencies. That agriculture is constantly
changing and needs to make constant readjustments is now a potent
conception in the rehabilitation of rural life.
The Extension Service aided farmers to take advantage of the
agricultural conservation program inaugurated this year and to
adopt other soil-improvement practices. It encouraged them to put
land in better shape by seeding legumes for hay and for soil im-
provement, by sowing or treating pastures, by terracing, by planting
cover crops, by strip farming, by listing, by building sod-saving
dams. Such work is going forward on a scale never approached
before.
When drought became serious this year the Extension Service aided
farmers in growing emergency crops and in making the best use of
the feed available. Temporary silos were built by the thousands.
Feed-supply surveys were made and feed supplies budgeted. Ex-
change lists of feed were distributed. Feeds and emergency fodders
were brought in from nondrought areas and distributed through
central agencies.
Extension agents and local leaders cooperated with the regional
agency set-up for clearing feed supplies. They helped farmers in
pooling their orders so that they might obtain reduced freight rates.
They helped farmers to make applications for crop-production loans
and feed and seed loans. In cooperation with the Agricultural Ad-
justment Administration, the Extension Service conducted State-
wide corn-fodder and feed-conservation campaigns. Water sources
were tapped.
THE YEAR IN AGRICULTURE 109
Combating Insect Plagues
Extension agents facilitated Federal and local cooperation in com-
bating insect plagues. Thus in Illinois county agents were notified
on June 8 that creosote would be made available by the Federal Gov-
ernment for building barriers against chinch bugs. At 9 : 30 the fol-
lowing morning orders for this Federal creosote were placed with
the Federal purchasing agent. In all, 1,281,800 gallons were allotted
to the 60 counties of the State where this pest threatened to do the
most damage. About 10,000 miles of chinch-bug barrier were con-
structed in Illinois with the Federal creosote.
In areas affected by the droughtj the consequences of which will be
felt for years, the Extension Service is seeking with the aid of tech-
nical advisers to determine what the future farming program should
be. It will encourage farmers to reorganize their cropping systems
and to initiate different soil practices wherever the conditions of soil
and climate warrant that course.
The farmers who have suffered are anxious for sound programs
for both long- and short-time needs. They want the facts from which
they may develop programs suited to their needs. The Extension
Service recognizes the resulting responsibility. With recovery, and
with time released from emergency projects, extension workers will
not simply go back merely to old lines of work. New and larger
problems demand attention, involving economic and social relation-
ships as well as production facitors. This calls for coordinated
research and planning.
Accordingly, extension agents and research agencies are pushing a
county agricultural planning project. After meetings with farm
groups in every county it is hoped to develop recommendations for
adjusting farm operations in terms of (1) national and interna-
tional economic influences, (2) rational land use, and (3) farm man-
agement. Such recommendations should serve to develop county
programs of the greatest significance.
City dwellers commonly think of farm life as synonymous with
good food and health. Yet in some rural sections the problem of
nutrition is acute. In certain areas some groups of farm people
actually suffer from a lack of essential foods, though most of these
foods could be produced there. The drought and the depression
made this situation worse. Therefore the Extension Service gave
more impetus to campaigns for growing and preserving food for
home use, and the campaigns met with an extremely favorable re-
sponse. County extension agents estimated in 1935 that the value of
the food canned or preserved on farms in that year was $18,875,090.
Home-produced vegetables, milk, eggs, meat, and fruit now appear on
the table of many a farm where formerly the idea prevailed that the
purpose of a farm was merely to produce crops for sale. The farmer
who makes a living on the farm will have that living and some cash
besides. When drought and depression strike, the family's living is
surer and better.
The relief load was lightened, too, by the work done to produce
food for home consumption in industrial centers. Thousands of
gardens brightened mine settlements and industrial towns and helped
to provide needed wholesome food. In one Eastern State the home-
110 YEARBOOK, 1937
garden and food-preservation movement required the services of about
125 garden supervisors and 175 canning supervisors. Four and a
half million pounds of produce was grown in these gardens. More
than a million cans of high-quality vegetables were prepared for dis-
tribution by welfare boards last winter.
Methods of Reducing Living Costs
Extension programs developed to aid people in lowering costs of
living Avere popular. In fact, extension work with farm families was
marked by constant adaptation to the problem of lowered family in-
comes, unemployment, relief, and social welfare. Encouragement and
instruction were given in producing handicraft articles and other
things for sale. Making, remodeling, and repairing garments were
taught.
Drought and depression and recovery have forced farm people
generally to recognize the needs of a profoundly changing country
life. They will continue to want help and direction in adjusting
themselves to these changes. By study and planning, many things
may be averted or their bad effects modified. By planning and acting
in cooperation with the community, the State, and the Nation, farmers
may make recovery more lasting. It is the task of the Extension
Service to furnish the information and the organizational help neces-
sary to accomplish this result.
COOPERATIVE RESEARCH PROJECTS
Federal and State agencies cooperated in new and extended lines
of agricultural research during the year, and improved their organ-
ization for greater service to agriculture and the general public. As
usual the State agricultural experiment stations worked closely with
other State agencies, with local organized groups, with each other
in regional groups, and with this Department individually and in
regional and national groups in efforts to plan and coordinate re-
search. Cooperative research thus fostered dealt not only with the
adjustment and relief policies of the National and the State Gov-
ernments, but with permanent policies of agricultural production,
land use, and rural life. The Office of Experiment Stations exam-
ined and recorded 818 new or revised formal cooperative agreements
between bureaus of this Department and the experiment stations.
The agreements covered 731 major research undertakings. All the
State experiment stations and all but one of the Department's re-
search bureaus participated. There were also many informal coop-
erative agreements, some of them of major importance.
Certain regional and national cooperative research undertakings
which had been started on an emergency basis as parts of the na-
tional recovery program in 1934 and 1935 were modified and ex-
panded to meet more permanent requirements. These studies
brought more closely together the parallel interests of plant- and
soil-science research and those of crop- and animal-production re-
search with more thorough consideration of their economic and social
influences. Studies of adjustments in farming by regions and type-
of-farming areas from the standpoint of national agricultural ad-
justment received considerable attention in this connection and were
THE YEAR IN AGRICULTURE 111
typical of the renewed and expanded efforts in cooperative research.
In this case, a review of similar work done the previous year indi-
cated the need for more complete studies.
A general plan for further action was agreed upon by State and
Federal representatives at the meeting of the Association of Land-
Grant Colleges and Universities in the fall of 1935, and formed the
basis of widely extended cooperative research in regional adjustment
policies in 1936. Nearly all of the States cooperated in this impor-
tant study. This Department contributed to the work primarily
through the Bureau of Agricultural Economics, but also through the
Agricultural Adjustment Administration, the Soil Conservation
Service, and the Forest Service. Among the State experiment sta-
tions it was common to find from 5 to 10 subject-matter departments
actively engaged in coordinating their studies so as to fit both State
needs and the national adjustment study program.
Another significant development in cooperative research during
the year was the adoption of a policy for establishing and operating
regional research laboratories under the Bankhead-Jones Act of June
29, 1935. Following negotiations with the land-grant colleges and
the State experiment stations, this Department issued a statement of
policy on December 19, 1935, which embodied suggestions from its
bureaus and recommendations from the State stations approved by
the executive body of the Association of Land-Grant Colleges and
Universities. Among other things, the statement of policy provided,
as a basis for the activities of the regional laboratories, that the
Secretary of Agriculture will receive suggestions from the experi-
ment station directors and from bureau chiefs in this Department;
that he will locate such laboratories solely with regard to the tech-
nical requirements and the facilities available; and that the Depart-
ment and the State experiment stations will enter into memoranda
of understanding regarding the work to be done, the cost of doing it,
the sources of the funds, and the coordination of the laboratory re-
search with regular activities of the States and the Department.
Federal and State specialists will cooperate in preparing detailed
Three Regional Laboratories Approved
In accordance with this policy three regional laboratories were
approved during the last fiscal year; one for research in vegetable
breeding; one for soybean research, with particular reference to the
industrial uses of soybeans ; and one for the study of grass breeding
and pasture improvement. In the agreement covering the soybean
laboratory, which is typical, 2 bureaus of this Department and 12
State experiment stations participated. It provides for integration
of research at the laboratory with research at the experiment stations
in the region and for the revision and reformulation annually of
the research program.
The study during the year of grain storage on the farm is typical of
the cooperative research into broadly important regional or national
problems, initiated uuder the provision in the Bankhead-Jones Act
for research by this Department other than at regional laboratories.
In this undertaking, three of the Department's bureaus and seven of
the State experiment stations, together with several other organized
112 YEARBOOK, 1937
Sate groups, cooperated in a manner which brought to bear on the
problem the correlated knowledge and training of several different
specialists. Besides avoiding duplication of effort, the arrangement
avoided unnecessary duplication of research equipment.
Before the fiscal year ended, officials of this Department and a
majority of the directors of the State experiment stations adopted a
memorandum of understanding covering research relationships be-
tween the Soil Conservation Service and the stations. It recognized
that effective cooperation in research by these agencies is primarily
dependent on working to a common end, rather than on financing,
and that each agency should contribute what it can in experience,
knowledge, and personnel. It was agreed that such research as may
be mutually agreed on with reference to soil erosion and its pre-
vention requires mutual helpfulness, if it is to be fully effective.
Accordingly, the memorandum provided that details of cooperative
research projects within a State shall be planned and executed jointly
by the State experiment station and the Soil Conservation Service.
This understanding has far-reaching significance because it recog-
nizes not only the need of regional policies in erosion control but
also the limitation of action by individual States and Federal bureaus.
Federal and State agencies cooperated during the fiscal year in a
national survey of plant and animal improvement. This provided
the basis for material published in the Yearbook of Agriculture for
1936 regarding the character and availability of superior germ plasm
in 19 plants and animals, and preliminary material for subsequent
work on other animals and plants. This cooperative study brought
together in a usable form the available information on animal and
plant genetics and exercised a favorable influence on the further
planning of similar studies.
As part of an enlarged Federal-State program in the study of land
utilization, land-use adjustment, and soil conservation the inventory
of soil resources was expanded to include 30 States. In six other
States the work was completed. The widespread cooperative efforts in
crop improvement were continued and expanded. Typical of these
were the forage-crop investigations which were extended to include
11 States; the work in 5 States was completed. Other similar, widely
cooperative researches were the breeding and improvement of grasses,
corn, and potatoes.
Important New Cooperative Studies
Cooperative studies on other agricultural problems included several
important new undertakings, among them a study of milk marketing in
New England, the development of a program of agricultural econom-
ics in New England, studies of tobacco and cotton diseases, an evalua-
tion of meat investigations, and a master study on human nutrition.
At a conference in November 1935, sponsored by the directors of the
interested experiment stations, plant pathologists engaged in tobacco
disease investigations in the southern tobacco-growing States formed a
permanent organization known as the Tobacco Disease Council. This
council laid plans for a coordinated attack on particular problems by
special groups composed of experiment station and Department spe-
cialists and including representation from a privately endowed uni-
THE YEAR IN AGRICULTURE 113
versity. A second conference, in June 1936, reviewed progress, took
steps toward further voluntary coordination and cooperation along
specific lines, extended the movement to more northern tobacco areas,
and united it with the efforts of specialists on insect pests.
A similar conference, initiated by experiment station specialists
with the cooperation of specialists of this Department on diseases of
cotton, resulted likewise in the organization in February 1936 of a
cotton disease council, with parallel objectives. As a result several
serious disease problems of the Cotton Belt were taken up coopera-
tively by experiment station and Department specialists.
Food and nutrition specialists of several of the middle western
experiment stations formulated a regional cooperative program of
research on the nutritional status of college women. There is accumu-
lating evidence of a relatively widespread chronic undernutrition
among young women of college age. An executive committee has
been appointed by experiment station directors to guide the work.
The cooperation of the medical staffs of departments of hygiene and
physiology has been enlisted.
FOOD AND DRUGS LAW ENFORCED
Artificially flavored and colored beverages which simulate genuine
fruit products are frequently found to be in violation of the Federal
Food and Drugs Act. Artificially colored, .acidulated, and otherwise
camouflaged products masquerading as bona-fide fruit beverages can-
not fail to reduce the utilization and consumption of fruit. Operation
of the Food and Drugs Act caused one manufacturer of an orange-
oil-flayored beverage to change his formula to conform to the label,
which indicated the presence of fruit juice. He began, in consequence,
to purchase annually about 1,000,000 gallons of orange juice. This
required some 10,000 tons of oranges. Previously the only orange
product used in his beverage was orange oil.
In the spring of 1935 it became evident that maple sugar and sirup
were occasionally contaminated heavily with lead. The contamina-
tion was traced to the use of sap buckets coated with lead alloy, and
steps were taken to obviate this threat to health. But large stocks
of the contaminated product were on hand. Investigations in this
Department have suggested a simple procedure for the elimination of
the poisonous contaminant. If this is successful, these stocks can
be salvaged, and it will be unnecessary to divert thousands of gallons
of the sirup and thousands of pounds of the sugar from food use,
with consequent heavy loss to the producers.
One of the problems always before food and drugs law enforce-
ment officials is that of the decomposition of foods. Procedures for
the better preservation of perishable commodities and methods for
the detection of unsound products, either in their raw state or as
ingredients of food compounds, are very necessary. Research in the
Food and Drug Administration constantly improves the technique.
The application of various methods of analysis specially developed by
the .chemist, the bacteriologist, and the microscopist, to detect un-
wholesomeness in foods, not only results in the necessary condemna-
tion and destruction of spoiled products, but frequently suggests bet-
ter methods of handling and storage.
114 YEARBOOK, 1937
The study of vitamins has practical applications in food and drug
enforcement. More than 4,500,000 gallons of cod-liver oil were used
in this country last year, of which approximately 95 percent was
imported. There are no statistics of the respective proportions used
for human consumption and animal feeding, but it has been esti-
mated that more than half of this oil is used for animal feeding,
mostly for poultry. Cod-liver oil added to poultry feeds yields
profits under efficient poultry management. When there is a lack
of sunshine it supplies the necessary vitamin D to obtain maximum
growth and egg production.
Surveys of the vitamin D content of the cod-liver oils used in poul-
try feeds revealed that a surprisingly large proportion fall below the
required standard for vitamin D. Some of the oils are practically
worthless. Examinations of a number of importations indicated that
a significant portion of the imported oils are deficient in vitamin D.
Cod-liver oils are now being examined for their vitamin content
before their entry is permitted. The detention of shipments pending
vitamin assays means inconvenience and expense to importers, but it
is the only way to assure the users that the product is of satisfactory
Livestock and Poultry Remedies
Of particular interest to farmers is enforcement of the Food and
Drugs Act with respect to livestock and poultry remedies. Annually
many of these are found to be worthless. During the past year the
Federal courts in three contested cases upheld the Government's ac-
tion against a contagious abortion remedy composed of cornstarch
with a trace of potassium permanganate, which was sold for from
$5 to $12 a pound ; a protection powder labeled as a preventive for
almost all the diseases of livestock and poultry, which consisted es-
sentially of Glauber's salt and baking soda, sold at $7.50 per hundred
pounds; a poultry remedy composed of water, alcohol, carbolic acid,
and potassium chlorate, at 75 cents per quart, labeled an effective
treatment for all poultry diseases.
Enforcement of the Food and Drugs Act on these veterinary
preparations prevents serious losses to farmers. The price paid for
the fake remedies is not the only thing involved. More serious is the
fact that reliance on ineffective drugs delays the application of the
proper treatment and sacrifices animals that might be saved.
ROAD CONSTRUCTION
Road construction administered by the Department during the year
included work on the main through highways, the construction of sec-
ondary roads reaching into farming areas, extensions of the main sys-
tem into and through municipalities, the improvement of roads in Fed-
eral areas, and the elimination of railroad-highway grade crossings.
A total of 27,373 miles of highways, roads, and trails, and 310 grade-
crossing structures were brought to completion during the year. Of
this mileage, 22,133 was improved with Federal funds administered
solely by the Department. The remainder consisted of 204 miles
of national-park roads built for the National Park Service by the
Bureau of Public Roads ; 2,319 miles of loan-and-grant projects of the
Public Works Administration, also supervised by the Bureau of Public
THE YEAR IN AGRICULTURE 115
Roads ; and 2,718 miles in work-relief projects, the labor on which was
supplied by the Federal Emergency Relief Administration. Other
costs connected with these projects were paid with Public Works
funds, and supervision was furnished by the Bureau of Public Roads
and several State highway departments.
The major activity of the Department in road construction con-
sisted of the administration of funds provided as direct grants to the
States for relief of unemployment through highway and grade-
crossing work and as Federal aid to the States for highway purposes.
The work was carried on cooperatively with the various State high-
way departments in accordance with the general plan of administra-
tion of Federal aid for highways., but modified to meet the need of
giving employment to those on relief rolls.
Work of this kind resulted in the completion during the year of
13,789 miles of roads and streets — 7,355 miles on the Federal-aid high-
way system outside of cities, 755 miles on city extensions of the
Federal-aid system, and 5,679 miles of secondary or feeder roads. On
these classes of highways combined there were completed 310 railroad-
highway grade-separation structures. Also completed were improve-
ments on 22 miles of flood-damaged highways, on 236 miles of forest
highways, and on 436 miles of highways through other public lands
built by the Bureau of Public Roads, and 5,684 miles of forest roads
and 1,965 miles of trails built by the Forest Service.
The current program at the end of the year involved a total of
25,812 mnV. in all classes of projects. It comprised 10,006 miles on
the Federal-aid system outside of cities, 991 miles on city extensions
of the system, 7,921 miles of secondary or feeder roads, 716 miles of
forest highways, 261 miles of public-lands highways, 537 miles of
national-park highways, 2,478 miles of loan-and-grant projects, and
2,902 miles of work-relief roads, the last three supervised by the
Bureau of Public Roads as agent for other Federal departments. The
current program also included 1,664 structures separating the grades
between railroads and highways.
Railroad Grade Crossings
Authorization of $200,000,000 to eliminate danger at railroad-
highway crossings under the Emergency Relief Appropriation Act of
April 8, 1935, enabled the Department, for the first time, to participate
in such work on a large scale with funds not subject to other demands
for highway improvement. It has included in the program many
urgently needed improvements not undertaken before because of
hesitancy to spend large amounts of highway funds on a few struc-
tures. Approximately 2,000 crossings are to be eliminated with the
new funds. Nearly 7,000 grade crossings have been eliminated with
Federal assistance since 1916, but comparison with this figure does not
give a fair picture of the value of the new work, because many of the
new projects are of exceptional importance.
The work of the last year resulted in the elimination of 300 grade
crossings either by structures or by relocation of the highway, the
reconstruction of 10 existing structures, and the installation of pro-
tective devices at 185 additional crossings. Work under contract and
approved at the end of the year will increase the number of grade
116 YEARBOOK, 1937
eliminations by 1,466 and the number of protected crossings by 813.
The total employment for the year on work supervised by the
Bureau of Public Roads was 1,673,935 man-months, or the equivalent
of an average full-time employment each month of 139,500 men. The
number of individuals actually employed, some of them on a part-
time basis, averaged approximately 195,000 persons per month. In-
direct employment in the production and transportation of equipment
and materials is estimated at one and six-tenths times the direct
employment for work of the character done during the year. This
resulted in an indirect employment of 2,678,000 man-months, and this,
added to the direct employment, gives a full-time employment oi
4,352,000 man-months, the equivalent of the full-time continuous
employment of 362,000 men.
Secondary or Feeder Roads
Secondary or feeder roads have been receiving increasing attention
from the Department. Actual participation in the construction of
such roads began in 1933 ; 15,037 miles of secondary roads have been
completed. Improvement of these roads is now a fixed policy of the
Department. The general demand for better farm-service roads is
reflected in the trend toward placing local roads under the control of
State highway departments.
State and Federal highway officials must now plan for the im-
provement of secondary roads while they continue to make needed
improvements on the main highways and to carry on work in still
another new direction — the improvement of main routes through
and around cities. Highway administrators face a difficult situa-
tion if they attempt to plan for these different classes of work on
the basis of the incomplete knowledge now available. Serious mis-
takes and set-backs to highway development can be avoided only by
knowing the amount of each class of improvement that is economi-
cally and socially justified and what will be the annual cost of
needed improvements. Plans must be based on a thorough study
of highway revenues, the sources from which they come, and the
fairness with which taxes for highwaj's are imposed.
Recognizing the need for highway planning on a businesslike basis,
the Department has invited all of the State highway departments
to participate in State-wide highway-planning surveys to be financed
with V/g percent of certain Federal highway funds and under spe-
cific legislative authority for the making of surveys and investiga-
tions for future work.
At the close of the fiscal year 40 States had indicated their desire to
carry on planning surveys, and work was under way in 31 States. In
these surveys data are being collected as to the highway mileage and
its present condition of improvement, the extent to which each road is
used, the extent to which various classes of residents use the different
classes of roads, and the amount of taxes they pay for road purposes.
It is believed that the surveys will result m the assembly of facts
necessary to the formulating of a definite, economically, and socially
defensible, integrated highway-improvement program.
Henry A. Wallace,
Secretary of Agriculture.
19 3 7 YEARBOOK OF AGRICULTURE
BETTER PLANTS
AND ANIMALS
Book II
A SEQUEL TO THE 1936 YEARBOOK ON PLANT
AND ANIMAL BREEDING
EDITORS
GOVE HAM BIDGE • E. N. BRESSMAN, Scientific Adviser
THE SECRETARY'S COMMITTEE ON GENETICS
O. E. REED, Chairman
Bureau of Dairy Industry
R. R. GRAVES
Bureau of Dairy Industry
M. T. JENKINS
Bureau of Plant Industry
ROLAND MCKEE
Bureau of Plant Industry
H. R. FULTON
Bureau of Plant Industry
F. J. STEVENSON
Bureau of Plant Industry
H. C. MCPHEE
Bureau of Animal Industry
C. \V. WARBURTON
Extension Service
E. N. MUNNS
Forest Service
J. T. JARDINE
Office of Experiment Stations
J. R. FLEMING
Office of Information
F. G. ASHBROOK
Bureau of Biological Survey
J. I. HAMBLETON
Bureau of Entomology and
Plant Quarantine
A. F. BLAKESLEE
Carnegie Institute of Washington
IN SENDING out to the public this second and last of the two
yearbooks on genetics and breeding, I would not want anyone to
think that they complete the account of the efforts of plant and
animal breeders in the United States. On the contrary, I would
wish these yearbooks to be looked on as pointing the way toward a
field of activity that will accomplish much more in the future than
has been accomplished in the past. Life is always changing be-
cause environment is always changing. There are always new
types of diseases, new insect pests, changes in soil fertility, changes
in consumer demands. The work of the plant and animal breeders
is directed to meeting these changes. It has only just begun. We
have reached our present stage of development largely by rule-of-
thumb methods; but discoveries not dreamed of a few years ago are
being made, and they counsel greater boldness in experiment and
promise closer control because they give us an increased under-
standing of the processes that go on in the minute cells ivhere life
has its beginning.
If genetics enables us to outdo nature's own efforts, it is because
it is in the tniest sense a science of cooperation with nature. We
want to do different things than nature does — for example, in the
creation of hogs with plump hams or ivheatX grass hybrids with
plump seeds — but we have to learn nature's methods of doing them.
I think that more knowledge of how to cooperate with nature for
our own good is the greatest need of the world today. Man's
control of his own future may depend in the long run on whether
his biological knowledge, which is constructive, can catch up with
his knowledge of the physical sciences, which has taught him so
much about how to destroy. He>iry a_ Wallace>
WHAT THE BOOK
IS ABOUT
GOVE HAMBIDGE, Principal Re-
search Writer, Office of the Secretary
XhIS book rounds out the work of the committee on genetics ap-
pointed by the Secretary of Agriculture in 1933. The task set for the
members of the committee was to make a national and to some extent
an international survey of practical breeding and genetic research
with those- plants and animals that are important in American farming.
The first fruits of the work appeared in the 1936 Yearbook of Agri-
culture as a series of papers dealing chiefly with the major crop plants
and classes of livestock. The present volume covers an enormous
and varied field, dealing with garden vegetables, northern tree and
bush fruits, subtropical fruits, flowers, nut trees, forest trees, forage
grasses and legumes, Angora and milk goats, turkeys, ducks, fur-
bearing animals, honeybees, and finally that good friend of the farmer,
his dog.
Many of the articles are unique in that nothing of a similar kind
has been done in their field, and the two yearbooks together probably
contain the most complete and up-to-dato account of breeding work
and genetic research in relation to farm plants and animals that can
be found gathered in one place. Even in those cases where there is
little work of a really scientific nature to report — and this is true in
some instances, for scientific breeding is by no means universally
applied as yet — the writer of the article has explored possibilities and
endeavored to foresee fruitful lines of effort. Indeed, the possibilities
of the future are necessarily a theme that runs through both books,
because this science of genetics is relatively young, and much as it
has accomplished in creating new forms of life better suited to the needs
of man than the old, its greatest achievements undoubtedly lie ahead.
The genetics yearbooks, it may be said frankly, have something
of the hybrid nature of much of the material with which they deal.
They are intended for two groups: (1) Readers who want to know
what is going on in the field of plant and animal breeding in order to
enlarge their understanding and to enable them to carry on their
farming operations more intelligently, and (2) students and others
who have, or expect to have, a closer concern with the science of
genetics. The latter group comprises scores of thousands of indi-
viduals, including young people now in schools and colleges who will
be the American farmers and the agricultural scientists of tomorrow — ■
some of them future leaders in shaping agricultural progress; a large
number of workers in various parts of the country who are engaged
in the practical effort to create better plants and animals ; and teachers,
extension workers, and others whose business it is to know as much
as possible about all the major factors in modern agriculture.
119
120 YEARBOOK, 1937
To combine the interests of these diverse groups in a single volume
is a difficult task, but judging from the generous reception given the
last Yearbook, the results have at least been characterized by a
certain hybrid vigor.
Another purpose also underlies this survey of breeding and genetics.
It is an attempt to make a frank appraisal of the present situation
on a major segment of the agricultural front — not only to sum up
achievements, but to expose weaknesses and shortcomings. The
reader of the 1936 and 1937 Yearbooks will admit that the short-
comings have not been neglected. In almost every case, it is shown
that we are far short of attaining the objectives that scientists believe
we may attain with means as potent as genetics. As a matter of fact,
though systematic breeding with such major crops as wheat has been
going on for some time and has shown splendid results, it has only
been begun in the last few years with many of the crops treated in
the present book, and it has not had time to show what it can do.
In other cases, the work is necessarily so slow that the results of the
very earliest systematic efforts are only now beginning to be used.
In the case of a new apple variety, for example, it takes nearly 40
years from the time the cross is made to the time when the variety
is actually in commercial production. Tree breeders live in the
present but think in the future.
On the positive side, however, there have been such outstanding
achievements as the development of the wilt-resistant Marglobe
tomato, which is now widely grown and saved the Florida producers
from ruin; strains of cantaloups resistant to powdery mildew and
of lettuce resistant to brown blight and powdery mildew — both of
vital importance to California growers; snap beans resistant to some
of the chief diseases that plague producers; cabbages resistant to
yellows; sweet corn of such uniform and superior quality that it has
remade canning practices; superior varieties of raspberries; blue-
berries far better than those produced by nature; a large number of
improved navel oranges from bud selections; and many interesting
new fruits created by hybridizing different kinds of citrus. Some
of the new varieties and strains of plants developed by this constant
activity are not yet quite ready for introduction.
Thus it is both heartening to discover how much has been accom-
plished and humbling to realize how little we know. There is probably
not one writer of these articles who does not feel that the effort to
sum up the past achievements and present status of the work in his
field has been worth while. It has forced him to find out where we
stand, to make a critical examination of what has been done, and to
bring together many scattered fragments, so that their significance
can be seen in the whole picture, including their relationship to the
work of others in different fields. It would be well if a similar audit
or stock taking could be made in other major branches of agricultural
science, and, in fact, such a plan is now projected in the Department.
Much of the material was collected, as in 1936, through cooperative
survey forms, or questionnaires, designed to survey the breeding and
research work in all State agricultural experiment stations and in
similar public institutions abroad. Private or endowed institutions,
and even individuals, were included sometimes when it seemed that
SUMMARY 121
they might have valuable data. The information reported from
institutions in the United States and Canada was in general consider-
ably more detailed and complete than that from overseas, but in the
latter case there was not always sufficient time to prepare complete
data. A great deal of work was required in filling out some of these
survey forms, and the Department heartily thanks all who cooperated.
The preparation of the papers was assigned to Department scientists
actively specializing in work with each kind or group of plants or
animals. The authors have drawn on their own experience and
knowledge, and on the whole field of technical literature, as well as
summarizing the information obtained from the cooperative survey
of plant and animal improvement. The only uniform rule adopted
for the papers was that the material of most interest to the intelligent
farmer or the general reader was to come first and to be put in language
as nontechnical as possible. The more strictly technical material
was placed last. Thus, after the principle successfully followed by
Jack Spratt and his wife, the general reader may skip the brief techni-
cal section at the end of most of the articles if he wishes, and the
technical reader may skip the first part of the article if he is so inclined.
Basic data and tables, including lists of plants with superior germ
plasm for various characteristics available for future breeding work,
appear in appendices to the articles.
Though the genetic background and breeding techniques are
essentially the same with a good many different plants, it will be
found that some discussion of these aspects of the work has been
repeated to a certain extent. Since each such discussion is related
to a particular organism, however, it seemed best to let the repetition
stand, partly for the benefit of readers who may be interested only in
certain articles. Moreover, the subjects dealt with in the present
book will appeal to a large number of gardeners, orchardists, bee-
keepers, and other enthusiasts or specialists who may have only vague
notions about genetics, even when they carry on practical breeding
with the plants or animals in which they are most keenly interested.
In such instances a certain amount of repetition should be useful in
making the basic facts understandable.
Four articles in the last part of the book — which some readers may
prefer to read first — deal in greater detail with some of these funda-
mentals. The science of genetics is not a particularly easy subject,
though its broad principles are not difficult to grasp, and anyone
who wishes to go very far in plant or animal breeding must be pre-
pared to undergo some mental discipline in the study of theory and
technique if he expects to get all the facts straight. But for that
matter, the details of the radio are not easy to grasp, either, yet there
are thousands of capable radio amateurs who know a good deal about
them. And in breeding work there is the advantage that the tech-
niques involved, and the facts of genetics as far as they go, are at
least relatively definite, which is more than can be said, for example,
of the technique of writing good prose or poetry.
These concluding articles have been written with the lay reader
in mind, but it will be found that they cannot be skimmed over like
a detective story. On the contrary, they need to be read with the
close attention that the detective in real life would give to some rather
138904°— 37 9
122 YEARBOOK, 1937
difficult technical evidence. For one of these articles we are indebted
to A. F. Blakeslee, of the Carnegie Institution of Washington, who has
been doing extraordinary things with the chromosomes of Datura, the
genus to which our common jimsonweed belongs. Research in the
field of unusual chromosome numbers is now attracting a good deal
of attention among practical breeders because it suggests unique
methods of creating new varieties and even new species of plants —
that is, methods that are unique insofar as man is concerned, though
it would seem that nature has used them from the beginning. For
the chronology of genetics we are indebted to Robert Cook, editor of
the Journal of Heredity, and to many of the leading geneticists and
breeders in the United States, who critically examined his manuscript.
E. N. Bressman has undertaken the difficult task of explaining some
of the theory on which modern breeding practices rest; and J. E.
Magness has dealt with the differences between vegetative repro-
duction and reproduction by seeds, which must be clearly understood
in breeding work.
For a glossary of genetic terms the reader is referred to the 1936
Yearbook of Agriculture.
SUMMARY OF YEARBOOK ARTICLES
In the following pages all of the articles in the 1937 Yearbook are
briefly summarized so that the general reader may quickly grasp
the scope of the work as a whole.
Vegetable Crops — Introduction
In comparison with such major farm crops as the cereal, fiber,
sugar, and forage plants, the vegetable crops are far more numerous,
less understood genetically, and usually more limited to regional or
national use. For example, superb English varieties of peas or
cucumbers, or Italian varieties of tomatoes, either do not do well in
this country or do not suit our habits and prejudices. In some coun-
tries Amercian sweet corn is not considered fit for human food; and
on the other hand, many vegetables commonly eaten in Asia are
unknown in the United States. Vegetable breeding, in other words,
is a highly localized affair. We draw on the whole world for variant
plant forms, obtained by the Division of Plant Exploration and Intro-
duction in the Bureau of Plant Industry, but today these are used
almost entirely as sources of genes for specific characteristics needed
to strengthen and improve our own favorite types.
Systematic vegetable breeding by public agencies in this country is
for the most part not more than 10 or 15 years old — in some cases,very
much newer. Prior to that time, for decades and generations indi-
viduals and commercial firms had been busy producing better vege-
tables, largely by mass selection, with a little hybridizing here and
there. Naturally, we owe most of our present varieties to the work
of these men. The number of improved new forms introduced by
public agencies is as yet very small, though in acreage they make a
more respectable total. They will steadily increase. The kinds of
problems that are pressing today, notably the urgent one of disease
resistance, and the increasing complexity of the research needed for
quicker and more certain results make the old haphazard methods
SUMMARY 123
obsolete, excellent as they were in their time, and necessitate a well-
organized scientific attack by public institutions. The commercial
agencies in turn benefit by the work of these institutions. Seed cer-
tification in itself, though not directly connected with breeding, has
been a State function of great value in holding the advances made by
breeders.
Two new Federal institutions are of unusual interest and potential
value. One is the United States Eegional Vegetable Breeding Lab-
oratory just established at Charleston, S. C, under the authority of
the Bankhead-Jones Act of 1935. This is the only station in the
United States devoted exclusively to vegetable breeding, and it will
be concerned with basic problems affecting the Southeast. The other
is the Great Plains Horticultural Field Station at Cheyenne, Wyo.,
where everything possible will be done to extend the meager list of
vegetables now available for growing under the trying conditions
found in this region.
There is a single appendix for most of the articles on vegetable
breeding in the Yearbook, and this appendix includes work being done
with some crops — sweetpotatoes and peanuts, for example — on which
there was too little material to warrant separate articles.
Tomatoes, Peppers, Eggplant
As in the case of some of our literature and other native American
products, Europe appreciated the tomato first, while Americans did
not generally know that it was good to eat until about 1850, and the
first improved varieties came from England and France. After 1870,
commercial breeders in this country were active in selecting chance
variants characterized by large handsome fruits, high yield, and
plants adapted to local conditions. Among the leaders in this work
was A. W. Livingston, of Columbus, Ohio. He and his associates
were geniuses at selecting and perpetuating superior tomatoes. By
1910 there was a rich range of varieties, and the old methods are still
used with some good results.
Chance variation is not certain enough, however, to meet the pres-
sure of modern needs for resistance to disease, heat, and cold, and
adaptability to long-distance shipment, new areas of cultivation, new
processes and uses. Since 1910, there has been a more systematic
attack on these problems by State and Federal workers, and a greater
use of genetic analysis and controlled hybridization to meet them.
Major attention has been given to resistance to fusarium wilt, but
nailhead rust, leaf spot, leaf-mold, mosaic, and curly top have all had
some attention. Practically speaking, no research agency today
would introduce a new tomato unless it was resistant to at least one
very troublesome disease.
Many State stations have done and are doing notable work in this
field, and the list of new varieties is growing to respectable length.
Federal workers have also been very active. The most important
variety of tomato in the world today, Marglobe, was developed by
Pritchard and Porte in the Department. Marglobe is highly resistant
to wilt under most conditions and to nailhead under all conditions,
and it came in time to save the Florida tomato-shipping industry from
ruin. But Marglobe has faults too, and it will be superseded by
124 YEARBOOK, 1937
better tomatoes that will develop from the active research and experi-
ment now going on.
Hot and sweet peppers, or chilis, also are native to tropical America.
There has been comparatively little breeding work with these plants,
and all the types grown today were known 200 or 300 years ago. A
few enthusiasts among private breeders, however, have made improve-
ments, particularly in uniformity, conformity to type, thickness of
flesh, and earliness of maturity. The New Mexico and the Louisiana
stations have introduced improved strains of hot peppers, and the
Massachusetts and Connecticut stations have introduced early sweet
peppers adapted to New England.
Even less systematic breeding work has been done with eggplant
because of the relative unimportance of this crop in the United States.
Native to the Tropics of the Old World, it has long been esteemed in
some of the oriental countries. All the important varieties grown
here were developed by private gardeners and seedsmen. The New
Hampshire, Rhode Island, and Wisconsin stations are doing some
breeding work for increased earliness, and the Central Experimental
Farms of Canada have introduced an early productive strain of
Black Beauty.
A rather impressive amount of research has been done on the
genetics of the tomato, but there is a great need for the development
of more accurate tests to measure degrees of resistance to disease as a
foundation for working out the inheritance of resistance. More basic
information of this kind is needed if practical breeding is to achieve
results with greater certain ty. Of great theoretical interest is the
newer work on forms with abnormal chromosome numbers — both
triploids and tetraploids have been produced artificially. There has
been much less genetic and cytological research with the pepper and
the eggplant. In the case of the eggplant, Japanese workers have
made some interesting studies of hybrid vigor and parthenocarpic
fruiting (without fertilization of the ovules).
Cucurbits
Cucumbers and muskmelons are believed to have come originally
from India and watermelons from tropical Africa. Pumpkins and.
squashes are of American origin. Columbus thoughtfully brought
muskmelon seeds to North America, and in a few years native tribes
from the West Indies as far north as Canada were growing melons.
The early commercial and private breeders did their job so well with
all these crops that some varieties originated over a hundred years
ago are still popular among growers. Indeed, improvement by
breeding today centers largely on fighting disease and spreading the
climatic range of some of the cucurbits.
Cucumber growers suffer heavy losses from mosaic, downy mildew,
and bacterial wilt. In the search for resistant varieties, plant breeders
of the Department of Agriculture have found promising material
among stocks from the Orient— China, Japan, India. Inbred lines of
these show considerable resistance to mosaic and some resistance to
mildew and wilt. Work is now in progress to introduce resistance
into otherwise good American varieties by hybridization. At the
Maine station, cucumber scab has received attention, and inbred
SUMMARY 125
lines pure for resistance, as determined by artificial inoculation, have
apparently been found.
The story of the development of our numerous melon varieties from
material drawn from many parts of the world is a complicated and
interesting one. The most striking work in disease resistance has
been in connection with powdery mildew, which suddenly became a
menace in the Imperial valley, the chief muskmelon section of the
United States, in 1925. By 1928 J. T. Kosa of the California station
and I. C. Jagger of the Department of Agriculture had discovered
resistant plants in material from India. Commercially useless, they
were crossed with good American varieties, then backcrossed to the
American parent variety to improve quality, and a resistant hybrid,
of which Hale Best is one parent, was ready for use by 1932. Further
backcrossing to Hale Best and 2 years more of selection brought the
still better Powdery Mildew Resistant Cantaloup No. 45 in 1936.
The mildew threat m this area has been beaten. Resistant strains of
Honey Dew and Honey Ball are now being developed.
The California station has recently developed superior watermelons
from the old Klondike and Stone Mountain, and from Russian stock
the Minnesota station has bred a watermelon that can be grown
farther north than others. The most serious watermelon disease is
fusarium wilt. Within the last few years, the Iowa station has bred
a number of resistant strains, and in 1936 both the Florida and the
California stations released new wilt-resistant watermelons. It is
interesting to note that the first recorded attempt to synthesize a
commercial plant resistant to a particular disease was a hybrid
between watermelon and stock citron (wilt-resistant but inedible),
made by Orton of the Department of Agriculture and produced in
1911.
Squash breeding has had rather different objectives — the production
of varieties superior in uniformity, earliness, quality, and appearance.
This has been done chiefly by isolating superior lines among varieties
rich in variable characteristics — a task that is facilitated by the fact
that inbreeding generally has no harmful effect on cucurbits (and,
conversely, crossing apparently does not result in hybrid vigor). The
Vermont station has been a leader in this work. The North Dakota
station has produced a squash of high quality in an attempt to create
a substitute for sweetpotatoes in the northern Great Plains area. The
California station and the Connecticut station at New Haven have
recently introduced new squashes.
Some inheritance studies have been made with all the cucurbits,
and interesting work has been done on reproductive responses, breeding
behavior, and pollination technique, in all of which there are peculiari-
ties not common to other plants.
Onions
The Israelites wandering in the wilderness complained bitterly to
Moses because they had no onions. The unique, pungent flavor of
onions makes them in no less universal demand today. Americans
consume well over a billion pounds a year, worth $17,000,000 to
growers — not counting the onion relatives, garlic, leeks, shallots, and
chives.
126 YEARBOOK, 1937
Varieties have a rather strict regional adaptability partly because
they refuse to produce 100 percent normal bulbs except with a certain
definite length of daylight. One group will do this with a short day
of 12 hours. Another requires a 13-hour day, and another I3)i hours.
Yellow Globe Danvers demands 14 }£ hours of daylight, and Sweet
Spanish strain no. 2 still more. Extra-early varieties, like Bermudas,
will not do well when seeded in the North because the day has already
passed the minimum bulbing length by the time seed is sown. Late
varieties will not do well in the South because when the day is the
right length for bulbing, heat, sunscald, pink root, and thrips retard
growth. These conditions can be changed when breeders develop
varieties resistant to diseases and insects and adaptable to a wider
range of climatic conditions.
The principal troubles of onions are pink root, smut, mildew, smudge,
neckrot, yellow dwarf, thrips, and bolting (premature seeding).
Until recently, there was little or no attempt to overcome these
troubles by breeding. Today the prospects look very promising.
One of the most valuable aids in breeding for resistance to various
troubles may prove to be the Japanese onion, especially the Nebuka
type. Nebuka onions belong to a different species than our onions,
and they are of very little use commercially in the United States
because they produce no bulbs. But they are resistant to various
diseases, insects, and adverse climatic conditions, and by suitable
crosses, these qualities can be transferred to American types.
Active work is in progress now in the breeding of hybrids with
Japanese onions that are resistant to thrips, pink root, and smut.
Work is also in progress in isolating strains of onions resistant to
mildew. Resistance to smudge, it has been determined, is due to a
certain acid associated with the pigment in yellow and red bulbs;
whether the genes responsible for this acid can be incorporated into
white onions remains to be seen. A substance in the outer scales of
colored bulbs also seems to be poisonous to the fungi that cause neckrot.
The Sweet Spanish variety of onion has beeniound to be very resistant
to the virus disease, yellow dwarf. Resistance to thrips shown by
certain varieties and species seems to be due to growth habits and
leaf shapes that fail to offer protection to the insects; perhaps there are
also other characters involved that help the plants to withstand injury.
Certain varieties have been found to be highly nonbolting, and these
are being crossed to produce nonbolting hybrids. Indications are that
the same thing may be done to secure resistance to freezing injury.
With such facts determined, the breeder is in a position to carry on
a well-directed program. Techniques of inbreeding and cross-breeding
are well developed. The onion is normally cross-fertilized, and
selfing results in rapid deterioration, but with care it produces pure
strains for hybridization. In making difficult species crosses — as
with Nebuka — flies are specially grown and let loose in a cage that
covers the emasculated seed parent and also contains a cut flower
stalk of the pollen parent.
The onion has been used in interesting studies to develop methods
of identifying specific chromosomes under the microscope, and there
has been some genetic analysis of the inheritance of color and of certain
abnormalities in chlorophyll development.
SUMMARY 127
Peas and Beans
Peas apparently originated in Ethiopia, and according to one
authority they are the only vegetable that can with certainty be
traced back to the Stone Age. They are also the first crop with which
controlled breeding was done to produce new varieties (by Thomas
Andrew Knight, 1787), as well as the plant used by Mendel in deter-
mining the laws of inheritance that founded modem genetics.
They reached their greatest perfection in England, and many
American varieties trace directly to the splendid products of the
famous English breeders, beginning with Knight, who introduced the
first sweet wrinkled pea. The most highly evolved variety so far is
probably Laxton Progress, which blooms at the eighth or ninth node
and is therefore a few days earlier than its nearest competitor, Hun-
dredfold— a characteristic that, to pea fanners, was worth years of
breeding effort.
American breeders received their greatest stimulus from the canning
industry after 1900. Slight differences in such characteristics as pod
size, pod curvature, tightness of peas in pod, number of peas in prime
condition at one time, node of first bloom, and straightness of stem
have been important breeding objectives to achieve the closest possible
adaptation to machine handling and other needs of the industry. In
garden peas, the chief American contribution has been a great reduc-
tion in the incidence of the defect known as "rabbit ear." Today,
preservation by freezing presents new objectives; and with all types of
peas, American workers are now concerned with breeding for resistance
to fusarium wilt and other diseases, as well as to insects and adverse
weather conditions. Active breeding work is being carried on by
several State experiment stations, notably Wisconsin, by the United
States Department of Agriculture, and by some of the larger seed
companies.
Elimination of strings was the chief objective of the early commercial
breeders of snap beans, and the most successful among them was
Calvin N. Keeney, of New York, who produced many varieties still
popular, including Burpee Stringless Green Pod, Giant Stringless
Green Pod, Stringless Green Refugee, and Brittle Wax. Later, the
ravages of disease made it imperative to give major attention to breed-
ing for resistance. New York State has led in breeding beans resistant
to anthracnose. The Michigan, Idaho, and Wisconsin stations, the
United States Department of Agriculture, and the Department in
cooperation with the Wisconsin station, have produced varieties
resistant to mosaic, and some of these are tolerant to bacterial blight.
Strains resistant to bea,n rust have been bred by the Department and
by the Virginia station. Thus the major bean diseases have been
overcome to some extent, and the work is being actively carried on
to make greater gains.
Little controlled breeding work was done with lima beans until a
project was recently started in the Department. All the present
varieties resulted from selection. Of the two most extensively grown
today — Henderson Bush and Fordhook (also a bush lima) — the
former was found on a Virginia roadside by a Negro laborer in 1885
and sold originally to a seedsman in Richmond, and the latter was
128 YEARBOOK, 1937
discovered growing in a field of pole limas in California in 1903. A
hardy, high-yielding strain recently selected by the California station
came from stock grown by the Hopi Indians.
Considerable genetic research has been done with peas, although
this plant proved to be far more complex genetically than Mendel's
early work would have indicated. To date, 68 genes have been listed.
Eesearch in bean genetics has also been extensive, and the inheritance
of disease resistance has received, and is still receiving, a good deal of
attention. Very little genetic research has been done with the lima
Cabbage and Its Leafy Relatives
At least 4,000 years ago men were eating the leafy wild cabbage
found on the coast of Europe and northern Africa; and this plant is
supposed to be the original ancestor of such varied forms as the culti-
vated cabbage, cauliflower, broccoli, green-sprouting broccoli, Brussels
sprouts, kale, collards, and kohlrabi. For our modern varieties of
these vegetables we are largely indebted to farmers and to the assidu-
ous work of commercial seedsmen, in both Europe and the United
States, beginning in the late 1700's.
The most important single achievement in modern cabbage breeding
in the United States has been the development of varieties resistant to
yellows (fusarium wilt) — an achievement that has saved growers from
ruin in many sections and paid an enormous return on the cost. The
problem was first attacked in 1910 in Wisconsin by L. R. Jones; and
later J. C. Walker, of the Department of Agriculture, and his associates
devoted many years to it. As a result of these intensive attacks, the
wilt risk is now eliminated and there are yellows-resistant cabbage
varieties of all the major types.
New varieties of cabbage that show improvements in other ways
have been developed in Pennsylvania, Louisiana, and New York ; and
at several other State stations, as well as in the Department, breeding
programs are in progress that promise worth-whileresults. The chief
objectives today relate to diseases other than fusarium wilt, improved
ability to hold up well in storage, better adaptation to particular
localities, and a closer approach to consumer preferences, which favor
a small or medium-sized hard head, mild or sweet in flavor, with crisp
or succulent leaves.
Cauliflower and kohlrabi seed cannot be grown most successfully in
this country, but broccoli seed can be, and new strains that mature at
different times have been developed by private seedsmen in California.
Green-sprouting broccoli has also been improved by breeding. New
strains of Brussels sprouts have been privately produced in Oregon,
and a new strain of kale has been released by the Virginia Truck
Experiment Station. The Louisiana Station has introduced a new
strain of collards.
One outcome of the breeding work with cabbage has been the
development of interesting practical techniques for handling the
plants and inducing the setting of seed under unusual conditions.
Self-sterility is a problem with this plant, and as a result of intensive
study much light has been thrown on the nature of self-sterility and
self-incompatibility not only in cabbage but probably in other plants
also.
SUMMARY 129
Wide crosses between the cabbage and other species of the
same genus have been fruitful in yielding cytological information,
and there have been genetic studies of the cabbage concerned with
the inheritance of characteristics of the leaf, the head, and the stem,
as well as of plant height, bolting habit, season of maturity, and
yellows resistance. Some work has been done on locating certain
genes in definite chromosomes.
Root Vegetables
The turnip, rutabaga, radish, beet, carrot, parsnip, salsify, and taro
are biennial plants, which means that they store a rich supply of
food (mostly starches and sugars) in their roots during the first season
to support growth during the second season, when they produce seed.
Early in his history man learned to take this food supply for his own
nourishment, just as he learned to steal the store of honey from the bee.
Over a long period of time improvements wrere made and definite
types were set in these root crops by crude selection. Even in our
own times, practically no other kind of breeding work has been done
with them. But though the results of mass selection have in some
cases been excellent — as with the carrot — the method no longer meets
modern needs. In particular, the attacks of diseases and insects
make it imperative to develop resistant types by the newer methods
of inbreeding, crossing, and the introduction of valuable germ, plasm
from wild forms of these species.
There is very little work of this kind to report. On the other hand,
there has been some interesting genetic research with these plants,
and the unusual difficulties that some of them offer in breeding
technique have been ingeniously overcome. The road has been
cleared to some extent for going ahead with practical breeding pro-
grams based on definite objectives.
In order to "purify" the genetic make-up of a plant as a basis for
combining desirable characteristics by crossing, it is necessary first
to inbreed the plant. This is difficult in the case of some of the root
vegetables. Turnips, rutabagas, radishes, and probably beets con-
tain genes that make them sterile to their own pollen or pollen of
certain other plants of the same variety. The mode of action of
these genes has now been worked out. They are rccessives and must
be present both in the pollen and in the ovule to produce self-sterility.
Their characteristics can be overcome to a considerable degree by
applying pollen to a bud before it opens; or they can be replaced by
"normal" genes through appropriate crosses; or naturally self-fertile
lines can be discovered by enough searching and the others discarded.
In the case of the beet, the extreme dustlike fineness of the pollen,
which can float in through tiny crevices, makes accurately controlled
pollination difficult. This has been overcome by suitable techniques.
The carrot was long thought to be self-sterile. Now it is known
that the ovary merely develops before the pollen of the same flower
is mature. Self-fertilization can readily be accomplished by using
pollen from an older flower on the same plant. The flower parts
are so minute that the usual methods of controlled pollination cannot
be used, but this has been overcome by making flies do the work,
inside special cages.
130 YEARBOOK, 193 7
Along with such technical developments, research has uncovered
facts about the inheritance of characteristics in these plants, some of
which are of importance agriculturally — for example, bark and flesh
color of turnip and rutabaga ; color, corkiness, early and late flowering
in the radish; color of root and top, and root shape in the beet; root
color in the carrot. Investigation of chromosome behavior has also
been fruitful. Certain wide crosses have been made, as between
radish and cabbage, radish and Chinese cabbage, turnip and rutabaga,
that may develop worth-while breeding possibilities.
Salad Plants
Since the public became vitamin-conscious, the salad crops —
lettuce, celery, endive, chicory, cress, and parsley — have increased
in importance. Very little scientific breeding work has been done
with any of these plants except lettuce and celery, the major salad
crops. The production of both is confined to rather specialized
areas. Lettuce, one of the oldest vegetables grown, came originally
from India or central Asia and was introduced into the United States
early in the colonial period. Celery, native to the Mediterranean
region, was long considered to be poisonous and has been eaten only
in modern times.
Lettuce breeders have several solid achievements to their credit.
Most notable of these is the development of the Imperial strains by
I. C. Jagger, of the Department of Agriculture. This work was
started in 1922 to meet the combined threat of brown blight and
powdery mildew, which were on the point of wiping out growers in
some of the largest western producing sections. The resistant
Imperial strains, developed by hybridization, saved the industry in
these areas.
Since transportation developments made possible the shipment of
western lettuce to the East, eastern consumers have preferred the
crisp western type. The present varieties of this type cannot be
grown well in the eastern climate. A start was made in 1928 toward
developing crisp-head types for eastern growers, and the first of these,
Columbia No. 1 and No. 2, were released by the Department in 1936.
A wholly new type of lettuce, Cosberg (a cross between Cos or romaine
and Iceberg) was also introduced in 1936. This is comparatively
free from tipburn, which is very troublesome in the East. The
Department is now cooperating with several eastern State stations
for the development of other crisp types adapted to local conditions.
Tipburn and mildew are both serious in greenhouse forcing. The
Ohio station has developed a tipburn-resistant strain of Grand
Rapids, and the Massachusetts Station a butter-head type, Belmay,
resistant to mildew.
Celery growers need earlier maturing plants and plants resistant to
yellows, premature seedstalk development (bolting), and pithiness.
Breeders have been attacking these problems. Michigan released its
Michigan Golden Yellows Resistant celery in 1933 and its Curly
Leaf Easy-Blanching (also yellows-resistant) in 1936. A new Non-
Bolting Golden Plume has been introduced by a private seed concern
in California. Pithiness has now been proved to be an inherited
characteristic, which paves the way for breeding nonpithy strains.
SUMMARY 131
Although lettuce flowers are difficult to handle in breeding opera-
tions, some genetic studies have been made on the mode of inheritance
of various characteristics, including plant height, time of flowering,
habit of growth, length, width, and area of leaves, and particularly
color. Genetic studies in celery indicate that pithiness is due to a
single dominant gene, and that bolting may also be a dominant
characteristic controlled by several genes but greatly influenced by
environment. „ „ _,
Sweet Corn and Popcorn
Some of the greatest advances in breeding technique in recent
times have been made with field corn — in particular, the method of
crossing certain inbred lines to produce a hybrid that has remarkable
uniformity and productiveness. These advances have naturally been
reflected in sweet-corn breeding also.
Two outstanding needs have dominated breeding work: (1) The
canning industry requires stocks that are as uniform as possible in
every way, besides having high yield. (2) The fact that sweet corn
cannot be grown in the South, largely because of the ravages of the
corn earworm and of bacterial wilt, makes it highly desirable to
develop resistant varieties.
Breeders have met the first need so effectively with the newer types
of hybrid corn that the canning industry itself has been revolutionized
by the uniformity in texture and consistency of grains and the
uniformity of ripening in the field. Whole-grain canned corn,
frozen packs, and new machinery have been made possible by the
work of breeders. About 80 percent of the yellow sweet corn grown
for canning now consists of the newer hybrids, and about half of this
is Golden Cross Bantam, a product of the Department in cooperation
with the Indiana station. Other States that have led in recent
breeding work have been Maine, Illinois, Connecticut, and Minnesota.
Not the least of the advantages of Golden Cross Bantam corn is its
resistance to bacterial wilt.
Promising work is in progress to meet the second major need —
extension of the sweet corn region southward — by hybridizing sweet
corn with the naturally earworm-resistant dent field corns of the South.
The factors that make this dent corn resistant to the earworm have not
yet been satisfactorily determined, but varieties developed from sweet-
dent hybrids like Honey June and Surecropper Sugar have more
resistance than any other sweet corn. Leaders in this work have been
the stations in Texas, Florida, Georgia, and California. Truck and
home gardeners in the South are keenly interested in these efforts.
The characteristic kernel composition of sweet corn, which dis-
tinguishes it from field corn, depends on a recessive form of the gene
for starchiness. The presence of this recessive prevents the conversion
of some of the sugar into starch. A good deal of work has been done
on inheritance in sweet corn.
Popcorn pops because the horny endosperm in which the starch
grains are embedded confines the steam generated by heat until it
develops sufficient force to explode the kernel. Popcorns differ in
popping expansion, and the differences can be easily measured. They
also differ in tenderness and flavor of the popped kernels, productive-
132 YEARBOOK, 1937
ness, and resistance to diseases and insects. Fortunately" high
poppability and tenderness seem to go together, but unfortunately
high poppability and productiveness do not, so that in breeding a
compromise is necessary between these two characteristics.
Breeding work with popcorn has been relatively limited, but it has
produced some promising results. Mass selection, based on actual
popping tests or on a rough comparison of the amount of soft white
starch in kernels (the more starch, the less popping expansion) is
useful in bringing about a gradual improvement in popping expansion,
at least up to a certain point. The improvement in a 6-year experi-
ment conducted by the Department in cooperation with the Kansas
station was about 36 percent, and the improved strain has been
distributed as Supergold. Hybridization of inbred lines has been
carried on by several stations. At the Minnesota station, 250 lines
of a selection of Jap Hulless were developed by inbreeding, then culled
to 7 lines by selection, and all possible crosses were made among the
7 lines. One cross was selected as superior; the hybrid, named
Minhybrid 250, has had a 16-percent higher yield and a 29-percent
higher popping expansion than the Jap Hulless used for comparison.
A continuation of this project with new inbred lines is now in prog-
ress in Minnesota. At the Iowa station, a promising three-way
hybrid, is now under test, and a group of inbreds is in the develop-
mental stage. In a cooperative project between the Department
and the Kansas station, 81 hybrids have been produced recently,
of which aboxit one-fourth show seme improvement in popping
expansion, and almost 90 percent show a marked improvement in
yield. The Michigan station is now carrying on an interesting ex-
periment in producing synthetic varieties by combining a fairly large
number of inbred lines.
Injury caused by diseases and insects is a distinct drawback in
commercial popcorn. In the case of some diseases, selection for
commercial characteristics tends also to bring about some selection
for resistance. In the Southern States particularly, damage from the
corn earworm and from storage insects is serious. The Texas station
has a project under way in which an attempt is being made to intro-
duce the insect resistance of their adapted field corn varieties into
popcorn of good popping quality.
Potatoes
Native to cool regions in South America, potatoes were taken to
Europe by early Spanish explorers and grown there for a hundred
years before they were introduced into the New England colonies
from Ireland (1719, Londonderry, N. H.).
For another hundred years, little improvement was made in varieties.
Then there was a rush to produce better potatoes. A minister, Eev.
C. E. Goodrich, of Utica, N. Y., laid the foundations for potato
breeding. He thought the ravages of late blight were due to loss of
vigor through long vegetative reproduction by tuber cuttings, and
he proposed to restore vigor by growing plants from seed. Some
170 varieties can be traced back to a single one of his seedlings,
Garnet Chili. C. E. Pringle, of Charlotte, Vt., was the first to make
systematic attempts to obtain seed by controlled hybridization.
SUMMARY 133
In the United States today, potato breeding is extensive and well
organized under a national potato-breeding program. Under this
program, the Department coordinates the work in 13 States that are
carrying on active breeding projects, with 21 States cooperating
in testing worth-while material developed in these projects. Regional
problems are considered, and States in which seed cannot be grown
obtain it from States in which it can be grown. The various Depart-
ment field stations and State agricultural experiment stations stress
different aspects of the general problem, but altogether practically
every aspect of potato breeding receives attention, including disease
resistance, yield, adaption to locality, earliness, tuber shape, smooth-
ness (depth of eye), cooking quality, breeding methods, genetic
analysis, and study of chromosomes.
The breeding methods include the full range of those used in modern
plant breeding — the introduction of new varieties or species, selection
of colonal lines, crosses between varieties, brother-sister crosses (sib-
mating), backcrosses to parents, selling and the recombination of
selfed lines (as in the breeding of hybrid corn), outcrossing to unrelated
strains, the synthetic building of strains by a combination of various
methods, and wide crosses between different species (as between a
cultivated and a wild form).
The outstanding problem is resistance to diseases, including a
whole group of virus diseases, late blight, common scab, fusarium wilt,
rhizoctonia, early blight, blackleg. These diseases add enormously
to growers' costs. Late blight, the most important, has caused losses
of 9,000,000 bushels of potatoes a year for the last 10 years; in 1928,
the loss was 28,000,000 bushels. The severest possible tests for
resistance are given, and so far very promising progress has been made
in the development of many varieties resistant to late blight, a large
number resistant to scab, a large number resistant to mild mosaic,
and one variety and several of its progenies immune from latent
mosaic. The search for disease resistance will be continued until
every possibility has been exhausted.
From a practical standpoint, six new varieties have been named
and distributed in the last 5 years (Katahdin, Chippewa, Golden, and
Houma by the Department; Warba and Red Warba by the University
of Minnesota). Another, not yet named, is being tested by farmers.
Katahdin and Chippewa are now firmly established as commercial
varieties.
With a wealth of available breeding material, breeding methods well
tested, considerable genetic and cytological information, and a
planned cooperative program, potato breeders are in a position to
expect further progress with confidence.
Strawberries
The strawberry is not of ancient lineage as a cultivated fruit,
though the Indians of Chile were growing remarkably fine selections of
the wild beach strawberry before the time of Columbus. Five plants
of this type reached France in 1714, and these were crossed with the
wild meadow strawberry of eastern North America, which had
previously been taken to Europe. The result was a vigorous hybrid,
the modern cultivated strawberry — a European creation out of Ameri-
134 YEARBOOK, 1937
can parentage, so welcome and adaptable that it is now grown from
Alaska to New Zealand.
Since the strawberry is relatively so new, most of our varieties are
products of breeding, though a few have been found as chance seedlings
in the wild. These are natural hybrids of cultivated and wild berries,
for many of the wild sorts now contain chromosomes obtained from
the pollen of their cultivated neighbors. Extensive commercial
production did not begin until after the Civil War, when the first
firm-fruited variety, Wilson, made strawberry growing in the South
possible. Today, 20 varieties created in the last 45 years (Gandy,
the oldest, in 1885) account for over 99 percent of the total acreage,
and 6 of these (Klondike, Howard 17, Aroma, Blakemore, Missionary,
and Marshall) for 78 percent. Most of the 20 varieties were produced
by private breeders, and several famous private breeders of outstand-
ing varieties are still living and carrying on their work.
Systematic strawberry breeding is now being carried on by the
Department and by the agricultural experiment stations in 26 States,
as well as in Alaska and Hawaii. Hundreds of thousands of seedlings
are constantly being grown, of which perhaps two in a hundred are
selected as worthy of a first fruiting test, and a very small percentage
pass the final rigid test and are named and introduced. At many of
these stations the work is new and has not yet had time to produce
results. The Department has released 7 varieties, Minnesota 16,
New Jersey 1, New York 21, North Dakota 1, Oregon 1, South
Dakota 2, Tennessee 1, and Alaska 1. Strawberry growers readily
adopt improved varieties, and such new introductions will account for
an increasing acreage in the future. Breeding work is also actively
carried on in Canada, England, Norway, Sweden, Germany, Switzer-
land, Czechoslovakia, the Union of Soviet Socialist Eepublics, Japan,
and Australia.
The usual method of breeders is to cross varieties and species and
backcross to the parents. The newer method of inbreeding and
combining inbred lines has been used very little, partly because the
strawberry plant loses vigor so rapidly with inbreeding. This method
will very likely be necessary, however, to eliminate recessive genes that
probably account for susceptibility to certain diseases as well as for
other weaknesses. There is considerable confidence today that the
excellent characteristics of many varieties and of the three wild
56-chromosome species (meadow strawberry, beach strawberry, Kocky
Mountain strawberry) can be combined in a few outstanding types
suitable for the wide range of strawberry-growing regions. Broadly,
the objectives today are greater resistance to several diseases, and
possibly to insects and nematodes ; greater resistance to high tempera-
tures, low temperatures, and drought; better adaptation to long
and short days; better dessert quality under adverse weather condi-
tions; increased firmness and toughness of skin; and better adaptation
to certain specific uses such as canning, preserving, freezing, and
flavoring.
Fundamental research with the strawberry has been concerned with
the inheritance of a few contrasting characters and with chromosome
behavior, largely in crosses between species with different chromosome
numbers.
SUMMARY 135
Blackberry and Raspberry
By clearing the forests, Americans set up a vast natural blackberry
breeding project, for in the clearings the sparse growth of blackberries
became dense, and since all blackberries need cross-pollination, a
multitude of natural hybrids arose. For the last 75 years or so we
have been making selections from this pool of mixed, germ plasm,
which has been the source of almost all our commercial varieties,
including Lawton, Eldorado, Snyder, and the dewberry or trailing
blackberry Lucretia. However, in the West the Logan (Loganberry)
came from a cultivated variety, the Young dewberry (Youngberry)
is an artificially produced hybrid, and the Evergreen (Black Diamond)
and the Himalaya are of European origin. Whether the Logan is a
blackberry-raspberry hybrid is still in dispute.
Comparatively little systematic breeding has been done with black-
berries by public agencies, but the Department and several of the
State stations are doing some work. There is much interest in
developing thornless varieties. This has been accomplished several
times by the use of mutations, but unfortunately only the outer
layers of the plant tissue carry the characteristic of thornlessness,
and new plants developing from the inner layers — as they do in the
case of root cuttings — are all thorny. Also, thornless plants generally ■
tend to be sterile. Other major practical objectives in breeding are
superior hardiness, productiveness, vigor, flavor, firmness, and size;
smaller seeds; and resistance to diseases, nematodes, and drought.
Many crosses have been made by the Department and by the New
York, Rhode Island, and Texas stations, and a few improved varie-
ties have been introduced as a result. Workers at the Texas station,
and in England, have been especially interested in experimenting
with blackberry-raspberry crosses, but none of these has as yet pro-
duced a worth-while commercial variety.
Both European cultivated red raspberries and selections from
native wild varieties were probably grown in the United States before
1800, but the red raspberry did not become commercially important
until after 1865, when an industry was founded on the famous Cuth-
bert variety, discovered as a chance seedling in New York. The best
cultivated red raspberries were developed by definite breeding work,
mostly by the State stations, far more than has been the case with
blackberries, and since this work began a considerable number of
superior varieties have been introduced, including such important
ones as Latham, Chief, Ohta, King, and Viking.
Breeding work is being actively carried on by the Department and
the experiment stations in New York, South Dakota, Illinois, Wash-
ington, Minnesota, Tennessee, and North Carolina, and many thou-
sands of seedlings that have resulted from crossing and selection are
being tested. This includes work with the black and purple rasp-
berries, crosses between red and black and between American varieties
and Asiatic species, and the development of fall fruiting or everbearing
forms and of varieties adapted to special purposes. Among other
results are the production of berries bigger than would have been
thought possible 10 years ago, and considerable success with varieties
able to resist or escape major diseases.
136 YEARBOOK, 1937
But there are still great possibilities for improving the red rasp-
berry, notably by bringing together in a single combination some of
the superior characteristics now found separately in cultivated Ameri-
can and European varieties. Moreover, a large number of wild
varieties exist in Asia and elsewhere, with extremely varied character-
istics of plant and fruit, that the breeder has hardly yet begun to use
in his programs. New possibilities will undoubtedly develop as these
are more systematically explored.
Currants and Gooseberries
White-pine blister rust is not passed from pine to pine ; it goes from
pine to currant or gooseberry and then back to pine. This is unfor-
tunate for currants and gooseberries ; they have had to be wiped out
in a good many places to save the pines. Extension of the now greatly
reduced acreage will depend largely on the development of resistant
varieties.
There are two kinds of currants, red and black. Of the red cur-
rants, live species, native to Europe and Asia, are considered especially
important for breeders, and most of the leading American varieties
(Fay, Wilder, Eed Cross, Diploma, and Perfection) came from two
of them. These American varieties were developed between 1877
and 1887 out of material that had been coming from Europe almost
since the first settlement of New England. The European black
currant is useless for this country because of its high susceptibility
to blister rust, but the American black currant — which also has
golden or white forms — is more resistant. Four improved American
black varieties (Tonah, Atto, Mato, Wanka) were introduced by the
South Dakota Station in 1925.
Very little systematic breeding work has been done with currants
by either State or Federal workers. The South Dakota station has
worked with black varieties ; a number of crosses have been made and
are being studied in New York; Minnesota has recently introduced a
red selection, Red Lake ; and Federal workers have made some crosses
and selections but have introduced no varieties as yet. The most
promising rust-resistant variety is Viking, an introduction from
Norway. It seems in fact to be immune and is now being extensively
tested by the Department cooperating with State stations. There
are promising possibilities in breeding work with currants, especially
the hardy, drought-resistant, vigorous American black varieties.
Greater promise, however, lies in the work with gooseberries. The
greatest development of this fruit has been among the English, who
became connoisseurs of gooseberries, held gooseberry shows, and
offered prizes that stimulated breeding work, especially for large size.
In the United States, gooseberry growers were discouraged by mildew
until after 1900, when fungicides were used to control the disease.
The most important gooseberry in this country has been Downing, a
mildew resistant variety introduced about 1855. Poorman (1896) is
the largest American-European hybrid. About a dozen species native
to the United States are promising for breeders. They have a wide
climatic range and such valuable characteristics as resistance to
mildew, leaf spot, and high summer temperatures. These character-
istics need to be combined with the great size, fine flavor, and attrac-
SUMMARY 137
tiveness of European varieties, and some of the hybrids developed
show the possibilities.
Breeding work has been carried on by several State stations. The
South Dakota station has made crosses between a native wild species
and European varieties, and these have resulted in some dozen
introductions. The North Dakota station has recently introduced
three varieties from crosses and is studying the inheritance of import-
ant characteristics. The New York station at Geneva has introduced
one variety, and the Minnesota station has introduced an improved
variety. The Illinois station is working for greater production, larger
size, higher flavor, fewer thorns, and resistance to leaf diseases. The
Department is doing some selection and hybridization, and has
recently introduced one gooseberry, Glenndale, adapted to the upper
South.
The breeding of both currants and gooseberries has been actively
carried on in Canada, and in England research work has proceeded
far enough so that the use of X-rays to induce mutations is now
being studied. Breeding work is also being done in Sweden and in
the Union of Soviet Socialist Kepublics.
Unusual Bush Fruits
All cultivated plants came originally from the wild, but only the
most outstanding or the most adaptable have been extensively grown
by man. Others from which men gather food might be adapted to
cultivation and improved by breeding, just as the wild blueberry has
been adapted and improved in recent years. Among the plants useful
for landscaping there are also a number that might yield new forms or
be made more valuable in other ways, if breeders would give them
systematic attention. For example, columnar deciduous trees other
than the Lombardy poplar might be created by breeding and would
be extremely useful.
A few ornamental plants whose fruit is promising as food have
received some attention. The actinidias (Chinese or Japanese
gooseberries) are climbing shrubs bearing fruit up to the size of an
egg, with a texture like that of a fresh fig, edible fresh or as a jelly or a
cooked sauce. A single vine may produce several bushels of fruit in
some years, but the need is to develop types that will bear regularly.
The American cranberrybush or highbush cranberry (a close relative
of the elderberry) produces fruit that makes a highly colored jelly of
strong flavor. Several State experiment stations have cooperated
with A. E. Morgan and the Department in improving this fruit by
breeding, and three varieties are now available commercially. The
goumi, or Eleagnus, has a tart fruit that is good in sherbets and is of
considerable importance in central Asia. The plant is hardy and
drought-resistant and might well be improved by breeding. The
fruit of the oriental or flowering-quinces (Japanese quince is a common
form) is extremely useful for jellies and preserves in combination
with other fruits because it is rich in pectin and contributes an agree-
able acid flavor. By breeding, it should be possible to develop larger
fruit, with more acid and pectin and better color, which would be of
great value in the preserving industries. The Chinese bush cherry
(Manchu or Nanking cherry) is now receiving attention for its fruit,
138004°— 37 10
138 YEARBOOK, 1937
which has an attractive tang and an agreeable range of flavors and
textures. This fruit too has commercial possibilities, and some
breeding work has been done with it in Iowa, New York, and Massa-
chusetts. ~
Blueberries
Only a short time before his death on January 9, 1937, Frederick V.
Coville completed an article for this Yearbook describing his work in
developing the cultivated blueberry from the wild blueberry. Dr.
Coville served 49 years in the Department of Agriculture, and prob-
ably his work with blueberries will stand out as the most important
achievement of a fruitful career. It founded a new and thriving
industry.
The work began in New Hampshire in 1906 with a study of the
fundamental facts in the life history of the wild blueberry. The first
fact established was one not before known — that blueberries, rhododen-
"drons, azaleas, the mountain-laurel, and many other plants require
acid soils.
Next, methods of grafting, budding, division, layering, propagation
of twig cuttings and root cuttings, and pollination were worked out.
Then plants with superior fruit were chosen for breeding experi-
ments. The first one, a highbush blueberry found in a pasture in
Greenfield, N. H., was named Brooks. To the excellence of this first
berry, Dr. Coville attributed much of the success of many of its later
descendants. Efforts were made to self-polinate the Brooks, without
success, and after other attempts, this method was abandoned in favor
of cross-pollination. Much later, it was found that in cross-pollination,
chromosome numbers were all-important. Even distantly related
plants with the same number of chromosomes would cross, but if they
did not have the same chromosome numbers, the cross yielded no fruit.
The second wild blueberry chosen was Russell, also from New
Hampshire. In 1911 this was crossed with Brooks, and some of the
first-generation hybrids were crossed with each other. Among 3,000
second-generation progeny, there was much segregation for various
characteristics.
Thereafter, Dr. Coville made an intensive search for superior wild
berries, enlisting the cooperation of Elizabeth C. White, of New
Lisbon, N. J. Up to the year 1936 about 68,000 pedigreed blueberry
seedlings were fruited and carefully tested for superior characteristics
of bush, size of fruit, ease of picking, size of scar when picked, size of
calyx, keeping quality, firmness, tendency to crack, and flavor.
Taste tests were especially exacting and, with the consumer in mind,
Dr. Coville would release no variety, no matter how remarkable its
size or how good its other commercial characteristics, unless its flavor
met his standards.
The largest berry developed in this work had a diameter of more
than 1 inch, but it was not released because of inferior flavor. A
hybrid between this and the finest-flavored berry, Stanley, has so far
reached a diameter of nearly 1 inch. It is not yet ready to release,
but Dr. Coville named it Dixi. His article describes the character-
istics and ancestry of all his improved varieties — Pioneer, Greenfield,
Cabot, Katharine, Rancocas, Jersey, Concord, June, Scammell,
Stanley, Redskin, Catawba, Wareham, Weymouth, and Dixi.
SUMMARY 139
Apples
To evaluate a new apple variety takes 25 years from the time the
cross is made, and another 5 to 15 years will elapse before it is in
commercial production. Practically speaking, the apple breeder works
for his descendants, not for his own generation. Therefore as yet few
of our widely grown varieties are the result of systematic hybridizing,
even though this work was under way in 1895. Most of them came
from superor chance seedlings. Apples were brought over from Europe
by the early colonists, the seeds were widely disseminated, and since
apples do not come true from seed, the range of differences in tree and
fruit was very great. In fact this process extended back into early
times. Primitive man appreciated the wild apple, though it was a
wry tiling, and he early began selecting and cultivating it. Budding
and grafting were practiced over 2,000 years ago.
Today we need fruit with quite definite superior characteristics,
and the hope of obtaining it lies in the extensive breeding programs of
the present and the future. What are the objectives? Increased
winter hardiness, of first importance in northern regions; disease
resistance (the major diseases are scab, blotch, bitter rot, fire blight,
and apple cedar rust); resistance to spray injury; late blooming to
escape spring frosts in some sections; a combination of rich-flavored
fruit with desirable tree characters (disease resistance, etc.); a greater
range of fruits with high color and quality combined with ability to
keep well in storage; varieties adapted to the far South — at present
there are none that are satisfactory.
There is sufficient variation among the many different kinds of
apples to give assurance that many of these desirable characters can
be brought together in new varieties.
Three methods are available to bring about these improvements:
(1) Keeping a careful watch for bud mutations ; this has been practiced
rather intensively during the last decade, and some very superior
strains have resulted. The method is still highly promising, though
it is limited to a relatively narrow range of improvement among exist-
ing varieties. (2) Hybridization to produce really new varieties by
combining different characteristics. In some cases it is possible to
go rather far afield; hardy crab apples are being crossed with com-
mercial varieties of apples, for example, to get extreme cold resistance.
(3) Producing varieties with unusual chromosome numbers. It hap-
pens that about 25 percent of our commercial apple varieties are
triploids — that is, they have three full sets of chromosomes in their
body cells instead of the normal two sets. Always these triploids
have unusually large fruit and a vigorous type of tree; that is why
so many of them happen to have been selected as superior. But the
occurrence of triploid apples is very rare in nature, and so far it has
been impossible to create them by controlled breeding methods. This
is a secret that the apple breeder is trying intensively to solve.
Breeding projects are under way at the experiment stations in several
States, and tens of thousands of seedlings are under test. So far,
the Iowa station has introduced 13 named varieties; Minnesota, 5;
Missouri, 7; New York, 15; South Dakota, 17. Work is also in
progress in Idaho, Illinois, Maine, Maryland, Massachusetts, Ohio,
140 YEARBOOK, 1937
and Virginia, and the Department is doing a limited amount of breed-
ing. A major program has been carried on in Canada, and apple
breeding is combined with the breeding of other fruits in several
European countries. _
Pears
Europeans have the same fondness for pears that Americans have
for apples, and a great many delicious varieties have been developed
in Europe. A Belgian physician, Von Mons (1765-1842), had as
many as 80,000 seedlings in his gardens and developed over 400
varieties. At least as early as 1794, however, pears in the United
States met the nemesis that has dogged them ever since. This is
fire blight, a bacterial disease that attacks roots, crown, trunk, limbs,
blossoms, and fruit. It is ruinously virulent in most of the East; in
the West, relatively cool dry summers make it less destructive; but
even there, it is a source of great trouble and expense to growers, since
the only known method of control is by careful surgery.
Thus the fire blight menace dominates pear breeding in the United
States. The European pear, source of all the fine-fleshed, buttery,
melting, aromatic varieties such as Bartlett, Anjou, Bosc, and Winter
Nelis, is especially susceptible. The Chinese or sand pear, coarse,
gritty, and inferior, is resistant. Around the middle of the last cen-
tury, hybrids between the European and the Chinese pear began to
appear — Le Conte and Kieffer, for example. Although these are
inferior in quality, they are about the only pears that have enough
blight resistance to be grown in most parts of the East. One pear
apparently of straight European parentage, the Seckel, is also resistant.
The problem, then, is to develop a wider range of the superior
European varieties with resistance to the disease, either by hybridiza-
tion or by selection. The most important basic breeding material
includes the European pear (generally susceptible but with occasional
resistant forms), the snow pear of southern Europe (susceptible), the
Chinese or sand pear (variable resistance), the Ussurian pear of
China and Siberia (very resistant, and especially valuable because
the quality is fair), the Callery pear of China (resistant), the birchleaf
pear of China (variable resistance). There is enough range in the
available material to meet all requirements, including superior winter
hardiness, which is needed in some parts of the country; but it may
be another hundred years before the problem of fire blight is really
solved, considering the length of time it takes to test a single genera-
tion of tree fruits.
The Oregon Station has led in this work. There F. C. Reimer has
tested the resistance of practically all known species and varieties of
pears, and of many hybrids, using artificial inoculation as well as
natural infection. One of the most valuable breeding stocks is a
highly resistant Anjou seedling called Farmingdale, found accidentally
on a farm in Illinois. Ten other very resistant Eurpoean pears have
been found in 10,000 seedlings, and all transmit a high degree of
resistance in crosses.
The Department has also carried on fairly extensive breeding work
for blight resistance, and 5,000 seedlings, inoculated each year, are
now being grown to fruiting. Work has also been done in California
(for range of ripening season), Georgia (studies of resistance), Iowa
SUMMARY 141
(winter hardiness), Maryland, Michigan, Minnesota, New York
(primarily for high quality and long ripening season), and Tennessee.
Some new varieties have been introduced as a result of this work.
A limited amount of work has been done on the cytology and genetics
of pears, but inheritance studies are difficult because selling is imprac-
ticable in most varieties. „
Grapes
Obedient to official urging and command, the early colonists in the
eastern United States planted grapes of the traditional fine European
varieties. All of these ventures failed miserably; the European
varieties could not stand the diseases, the insects, and the cold that
faced them in this part of the new land. In California, however, they
throve ever since they were introduced by Mission Fathers from
Mexico in 1769, and after 1850 grape culture in that State grew with
great rapidity. Meanwhile, tardily, easterners began to become
aware of the value of their own native grapes, which grew abundantly
in the wild. Three chance seedlings — the Cape (believed to be
identical with Alexander), discovered in 1806; the Catawba, first
propagated in 1819; the Concord, named and introduced in 1854 —
had sufficient merit and popularity to turn the attention of breeders
to these native species. Thereafter several men did notable work
in selecting native varieties and hybridizing them both among them-
selves and with European grapes. Outstanding among these early
workers were E. S. Rogers (Agawam), A. J. Caywood, Charles Arnold
of Canada, G. W. Campbell (Campbell Early), Louis Suelter (Beta),
J. H. Eicketts (Downing), and T. V. Munson, who originated more
hybrids than any other man in the country.
Thus American grape growing has had two distinct lines of develop-
ment. On the Pacific coast (especially in California), where 90 per-
cent of the commercial grape culture is centered, European varieties
are grown for the production of table grapes, raisin and currant
grapes, and wine grapes; throughout the rest of the country, native
varieties, hybrids between these, and hybrids with European varieties
are grown for table grapes, wine grapes, and unfermented-juice grapes
(the foxy flavor of the Concord, which is a fox grape, is important for
this last use). Even the European grapes in California, however,
must be grafted on native American rootstocks, which alone are
resistant to phylloxera, an American insect that, finding its way to
Europe, compels European growers also to use American grapes as
rootstocks.
Grape breeding is actively carried on by the Department and by the
State agricultural experiment stations in California, Georgia, Mary-
land, Minnesota, Missouri, New York, South Dakota, Texas, and
Virginia. Many thousands of seedlings from an immense number
of crosses are being grown and tested, and improved varieties have
been released by the Georgia, the New York (Geneva and Fredonia),
and the South Dakota stations. The general objectives in this work
are improved fruit quality, disease resistance, and local adaptability;
but there are separate objectives for the three main types of grapes.
Thus, for American native bunch grapes it is desirable to have larger
clusters and berries; some of the rich vinous flavor of the European
grape ; more edible skin, more melting flesh, seeds more free from the
142 YEARBOOK, 1937
pulp, increased sugar content. For the native muscadine grapes of the
South, it is desirable to have larger bunches, better adherence of berry
to stem, more tender skin, better flavor, smaller seeds. For the
European grapes, it is desirable to have among the table types, more
seedless varieties and a larger assortment of black, red, and white
grapes ripening from early to late; among the raisin types, several
improvements to meet specific needs ; among the wine types, improved
flavors (perhaps a blend of several flavors for certain kinds of wine),
juice of better color, vines resistant to phylloxera to eliminate the
necessity for grafting.
Needless to say, grape-breeding work is also being actively carried
on in foreign countries, notably France, Germany, Italy, Czechoslo-
vakia, the Union of Soviet Socialist Republics, and Australia.
Genetic analysis is slow, and there is need for more information on
the inheritance of characters of importance, especially resistance to
Stone Fruits (Peach, Plum, Cherry, Apricot)
Grown in China thousands of years ago, the peach early spread
throughout Europe and was brought to North America by the
colonists; but commercial growing did not begin here until the nine-
teenth century, when orchards propagated from cuttings were first
established. Between 1850 and 1900, peach growing became highly
specialized, and to meet the need for types suited to different regions
many varieties were developed by seedling selection, including such
present stand-bys as Hale Early (1850), Belle and Elberta (1870),
Crosby (1876), Champion (1880), Carman (1889), Rochester (1900).
Today, systematic breeding by hybridization is conducted by the
Department of Agriculture and by the agricultural experiment stations
in California, Illinois, Iowa, Maryland, Massachusetts, Michigan,
New York, New Jersey, Texas, and Virginia, as well as in Canada.
Many of these have only started recently, but the Department has
introduced 4 varieties (1935), New Jersey 18 (1925-34), California 1
(1933), Iowa 1 (1932), Michigan 1 (1932), and Canada 6 (1925-30).
The extent of some of this work can be realized from the fact that the
New Jersey Station maintains 276 varieties of peaches and nectarines
(a smooth-skin peach) on its breeding grounds for study and hybrid-
ization.
Objectives, of course, are different at different stations, depending on
regional requirements and on the use for which the crop is intended.
In general, there is still a need for a variety of high quality adapted to
cold climates, and one that will not delay coming into leaf in climates
where the winters are warm. Better varieties than Elberta — the
best commercial peach so far — have been produced, but they are not
so widely adapted. Promising hybridization work is now in progress
with the Crawford type, which has very high quality, and with the
J. H. Hale. A good deal of interesting genetic work has been done
with the peach, but there is need for more.
Of the many species of plums native to various parts of the world,
four are especially important commercially in the United States — the
European plums, brought over by the first colonists, large, attractive,
green and golden yellow (Reine Claude) to red and dark purple (Italian
prune); the damsons of the Old World, yellow (Mirabelle) to blue
SUMMARY 143
(Shropshire), small, tart, used for preserves; the Japanese plums,
introduced into this country in 1870, yellow overlaid with red (Kelsey,
Burbank), excellent flavor; the native American plums, especially the
Prunus Americana species (De Soto, Weaver), red to reddish orange,
good quality but a thick, tough skin and clinging pit. These species
are rich in varieties available as breeding material, and there are also
many other interesting species.
Several private breeders have done notable work with plums, includ-
ing H. A. Terry and C. G. Patten, of Iowa, and J. W. Kerr of Mary-
land, who were interested in the selection of native varieties; Luther
Burbank, who selected and hybridized Japanese plums and other
species; Millard W. Sharp and A. F. and August Etter, of California,
who are now engaged in hybridizing.
Much systematic hybridizing, both among the plum species and
between plums and other stone fruits (cherry, apricot) is being con-
ducted by State stations in California, Iowa, Minnesota, New York,
and South Dakota, and by Federal field stations in California and
North Dakota. Where the work has been longest in progress, as in
South Dakota, New York, and Minnesota, several varieties have been
introduced; elsewhere, promising material is still under test. The
growing of plums has been declining in the United States during the
last 20 years, and there is a great need for the breeding of varieties of
really high quality adapted to regions characterized by extremes of
heat or cold.
There are two species of cultivated cherries, the sweet and the sour.
Sweet cherries are subdivided into two groups' — heart or gean cherries,
soft, tender, either dark colored (Black Tartarian) or light (Coe);
and bigarreaus, firm, crisp, either black (Bing) or light (Napoleon).
There are three groups of sour cherries — the amarelles, light (Mont-
morency); the morellos, dark (English Morello); and the marascas,
native to Jugoslavia, used for making maraschino cherries. Duke
cherries (May Duke) are probably hybrids between sweet and sour
species. Other species useful in breeding include the Nanking cherry
of Asia ; the sand cherry, the western sand cherry, and the chokecherry
of the United States ; and the mahaleb cherry of Europe and the pin
cherry of North America, used as rootstocks. _
Commercial production of sweet cherries is practically limited to
the Pacific and intermountain States, and that of sour cherries to
regions along the Great Lakes. The trees are too tender for colder
regions; they do not thrive in hot, dry regions; and in hot, humid
regions cherry diseases are disastrous. Breeding work is very much
concerned with overcoming these major handicaps and making this
delicious fruit available over a much greater area, and also over a
longer season.
There has been little work by private breeders, though the develop-
ment of black bigarreau varieties (Republican, Lambert, Bing) by
the Lewelling brothers founded the cherry industry in the Pacific
States. Among State stations, New York (Geneva) has taken the
lead, introducing two new varieties so far. South Dakota has intro-
duced several varieties, and work is in progress at the Iowa and
North Dakota stations, the Federal field station at Mandan, N. Dak.,
and in Canada, where one new variety has been introduced. In
144 YEARBOOK, 1937
addition, collections of breeding material are maintained in Ohio,
Colorado, Utah, California, and Oregon. In the search for necessary
characteristics, native American wild cherries are being extensively
used in some of this breeding work.
Apricots (probably native to China) are grown commercially only in
Pacific Coast States because the blossoming habit of the trees makes
them particularly susceptible to spring frosts in the colder regions.
The species grown commercially is the common apricot, but several
other species and subspecies are useful for breeding, including the
black apricot, the Japanese apricot, the Russian apricot, and the
Manchurian apricot. The raw material used by breeders consists
largely of older varieties from England (Blenheim, Moorpark), from
France (Peach, Guillans Early), and from the Union of Soviet Socialist
Republics (Alexander, Budd), and newer American strains (New-
castle, Alameda). The chief objectives of breeders are to combine
the good characteristics of these varieties and eliminate the faults;
and also to develop hardier types adapted to a wider territory. Apri-
cots from northern Asia are particularly hardy, but there is need for
still more material of this sort.
Among the wide crosses that have been made is that of the apricot
with the plum, producing the so-called plumcot* — though some
cytologists do not consider this a true hybrid.
Systematic breeding with apricots is quite new. The Department
began work at Palo Alto, Calif., in 1922, and about 60 promising
hybrids are now being studied and tested. Work began in New
York (Geneva) also in 1922, and so far one variety (Geneva) has been
named. In 1924 the North Dakota and the South Dakota stations
began breeding work; the latter station has been experimenting with
material from Manchuria and Siberia. Breeding work in Davis,
Calif., began in 1930. Apricot-breeding projects are also in progress
in Australia and Morocco.
Citrus Fruits
Grown for thousands of years in the Orient, citrus fruits were estab-
lished in Florida by 1579 and California by 1769 and were worth over
134 million dollars to growers in the United States in 1934. They are
an outstanding source of vitamin C and an important source of vitamin
B. Their unique sprightly flavors come from a combination of sugars
(sweetness), acids (tartness), glucosides (bitterness), esters (aroma),
peel oil (aroma). The chief types, including those used as rootstocks,
are sweet orange, sour orange, King orange, tangerine orange, satsuma
orange, shaddock, grapefruit, pummelo, citron, lemon, lime, Ichang
(lemon), kalpi, calamondin, and kumquat.
Today, large production, decreasing returns, and increased compe-
tition place great stress on improvement by breeding. Breeding
work was begun in Florida by the Department in 1892 and by the
State stations in California in 1910, in Florida in 1924, in Alabama in
1933, and in Texas in 1934. It is being carried on in Hawaii, Mexico,
Brazil, Argentina, Spain, Italy, Greece, Morocco, Palestine, Japan,
China, India, Zanzibar, Australia, and New Zealand.
Improvement of citrus fruits in the United States prior to the use
of modern breeding methods was by introduction of varieties from
SUMMARY 145
abroad, the selection of chance seedlings, and probably selection of
some bud mutations. The record of the earlier development of varie-
ties is full of interesting vicissitudes. Among the outstanding suc-
cesses is the story of the Washington Navel orange. Through the
help of a missionary, William Saunders, who was then Superintendent
of Gardens and Grounds in Washington, D. C, got 12 navel orange
trees from Bahia, Brazil, in 1870. Mrs. Eliza Tibbetts, migrating to
Riverside, Calif., in 1873, took two of them along. They proved to
be almost as important in California history as the discovery of gold,
since all of California's Washington Navel orange plantings came from
these two original trees.
The objectives of breeders today include: Tree characters — com-
pactness, vigor, productiveness, disease resistance, cold resistance,
congeniality with rootstocks, and correct market maturity. Fruit
characters — high dessert quality, seedlessness or near seedlessness,
correct size and shape, good shipping and storage quality, attractive
exterior, standard vitamin C content, firm pulp for canning, and
attractive juice color. There are o'ther special requirements for
rootstocks. In the past the chief methods of improvement were by:
(1) Selection of superior seedlings without controlled pollination.
Citrus fruits have the peculiarity of producing several seedlings from
one seed. Usually only one is the product of the union of male and
female parental cells; the others are practically buds within the seed
tissue and are produced nonsexually. This adds to the difficulty of
breeding work. (2) Selection of superior bud mutations. This has
been very important since the intensive studies made by A. D.
Shamel, of the Department, and his coworkers. In the last 18 years,
probably 10 million buds have been sold to California growers alone
as a result of this work. (3) Hybridization, especially between
different species of citrus. This method is being used chiefly to
create new types with unique flavors and other characteristics.
The last two improvement methods are still actively employed.
Hybridization is being carried on by the Department and State
stations, with promising results in several cases. Almost every kind
of citrus fruit has been crossed with almost every other kind. Among
the new typos produced are the tangelo (mandarin orange X grape-
fruit); tangelo X grapefruit; tangerine X sweet orange; Perrine lemon
(lemon X lime) ; citrange (trifoliate orange X sweet orange); citrange-
quat (citrange X kumquat) ; citrangedin (citrange X Calamondin) ;
limequat (lime X kumquat) ; tangemon (mandarin X lemon) ; tangor
(orange X mandarin) ; orangelo (grapefruit X orange) ; oramon (lemon
X orange); lemelo (grapefruit X lemon) ; lemon X grapefruit; lemon
X citron. The hybrids are so numerous and varied that naming
them is becoming a problem in itself.
In connection with breeding work, several technical problems are
being studied, especially polyembryony (the asexual production of
embryos) and the inheritance of disease resistance.
Subtropical Fruits Other Thajj Citrus
While many of the subtropical fruits important in other regions,
such as the loquat, jujube, cherimoya, granadilla, jaboticaba, and
white sapota, are relatively unimportant in the dietary and agri-
146 YEARBOOK, 193 7
culture of the continental United States, others, such as the pineapple,
fig, olive, avocado, and date, are the basis of established industries;
and still a third group, including the mango, papaya, lychee, and guava,
give promise of taking rank with those already firmly established.
Most of those in the first group are adapted to one section or another
of the United States, or to Hawaii, the Philippines, Puerto Rico, and
the Canal Zone. With practically all of these fruits, breeding work
and genetic studies are only at their beginning in this country, though
there are some extensive and valuable collections of germ plasm made
by such farsighted plant explorers as David Fairchild and Wilson
Popenoe and their coworkers. Though the areas of possible cultiva-
tion are limited, interest in several of the subtropical fruits is growing,
and with it the need for superior forms achieved through breeding.
The raw material is fascinating in range and variety, and breeders
are sufficiently well acquainted with it to have worked out techniques
and determined the desirable objectives in considerable detail.
Fig growing is now the basis of a sizeable industry in California
and Texas. Smyrna fig culture in California did not get into its
stride until the discovery, at the end of the last century, that a small
wasp, which makes its home in the inedible capring, is necessary for
the pollination of quite a different type, the Smyrna fig of commerce.
Improvement of figs — as of most other subtropical fruits — since that
time has been largely by introductions from abroad and the selection
of superior strains. However, hybridization has been conducted in
California since 1922, and of some 4,000 hybrid seedlings that have
fruited, several have been found with desirable characteristics. In
Texas, hybridizing was started in 1935.
Avocado breeding is in the fortunate position of having a rich col-
lection of varieties brought in by Wilson Popenoe and some of the
early pioneers, available for hybridizing to obtain combinations of
resistance to low temperatures, high quality, long range in marketing
season, and other superior characteristics. These varieties are being
intensively studied and several worth-while selections have been
made. Although hybridizing has only begun, some excellent hybrids
have already been secured and the future looks promising.
Thousands of date offshoots have been brought into the United
States by the Department of Agriculture and others, totalling over
140 varieties, and of these some 16 varieties are now important in
Arizona and California and many varieties are under test in Texas.
Date breeding is an extremely slow process. Methods of controlled
pollination have now been worked out, but progress so far has been
by mass selection.
Pineapple growing has been revived in Florida since 1933; it is
extensive in Hawaii, and fairly extensive in Cuba and Puerto Eico.
Hybridization has been begun by the Department; some work is
being done in the Philippines ; but most of the breeding work is in
Hawaii, where promising results are being secured.
The papaya, a "tree melon", is counted an outstandingly fine fruit
by those familiar with the best varieties. Florida seems best adapted
to papaya culture in the United States, though the fruit is grown in
California and Texas also. It is very important in the dietary in
Hawaii, the Canal Zone, and the Philippines. .The Department has
SUMMARY 147
introduced many strains and related species, and a breeding project
is now in progress. Breeding work is also being done in Hawaii, the
Philippines, and the Union of South Africa.
The mango, one of the oldest of cultivated fruits, with a flavor
somewhat like pineapple and apricot combined, is grown in Florida —
where over 200 introductions have been made by the Department,
including more than 50 varieties and a number of related species —
as well as in the island possessions of the United States. No method
of controlled pollination has been worked out, but selection of superior
seedlings holds considerable promise, and it is now being practiced in
breeding for disease resistance and other characteristics.
Miscellaneous subtropical fruits with which little breeding work
has as yet been done in this country include the olive, persimmon,
granadilla, guava, feijoa, jaboticaba, pomegranate, jujube, lychee,
loquat, white sapote, and cherimoya. All have possibilities for im-
provement and some are exceptionally interesting.
Nuts
Until recent years there was practically no attempt to develop
better nut trees by controlled breeding. Nature's products usually
seemed quite good enough. There is not much breeding work under
controlled conditions today, but it has been started, and though the
work has many difficulties , it also has very great possibilities for those
with the inclination," the time, and the facilities to carry it on.
Chestnut breeding became a pressing need because the American
chestnut, a magnificent tree characteristic of large forest areas in the
eastern United States, was practically killed out by chestnut blight,
a disease from the Orient that first appeared on Long Island, N. Y.,
in 1904. Some hybridization of American and European chestnuts
had been done before the blight appeared, but the hybrids were
doomed because both parental species are highly susceptible. The
Japanese chestnut tree is quite resistant, but the nuts lack flavor.
Much more promising is the Chinese chestnut (first extensively intro-
duced into the United States in 1907), which is highly resistant to
blight and produces a nut as large as the European and often as fine
in quality as the American. Present selection and hybridization
work, therefore, is practically confined to the Chinese chestnut, with
consideration being given to the Japanese. The Department and
the Illinois station are engaged in this work, as are several private
breeders. No variaties have been officially released by public insti-
tutions as yet. Chestnut blight will quite probably be overcome by
breeding and it is not impossible that another major enemy, the
chestnut weevil, will also be overcome.
Commercial filbert growing is confined to a region in the Pacific
Northwest, particularly the Willamette Valley of Oregon and parts of
western Washington naturally adapted to the superior filbert varieties
of two European species (Barcelona, Du Chilly, Daviana, White
Aveline are well known horticultural varieties of these). In the east-
ern United States these European filberts are handicapped by a fatal
blight, which spreads to them from the American species, and by lack
of winter hardiness. A few somewhat superior American varieties
(Rush, Littlepage, Winkler) are available for growing in the East, but
148 YEARBOOK, 1937
the breeding problem here is one of developing hybrids with resistance
to disease and cold. In the Pacific Northwest, the problem is to
develop filberts commercially and culturally superior to those now
grown. There is a good supply of breeding material, and work is being
actively carried on by the Department (at Beltsville, Md., and Cor-
vallis, Oreg.), the Minnesota station, and the New York station at
Geneva, as well as by several private breeders.
The breeding of pecans, the most important nut of the hickory
group, is somewhat confused by existing uncertainties as to the sizes of
nuts wanted by the market. The shelled-nut market wants very
small pecans, and there is doubt as to whether they can be grown
profitably except in uncultivated forest groves. The one-time de-
mand for very large pecans has steadily diminished, so that breeding
for extra size no longer seems desirable. In addition, most of the best
of the older varieties of pecans proved to have so many drawbacks
that the nuts are no longer marketed by varieties (as are apples and
pears), but the varieties are blended. Nevertheless, selection and
hybridization proceeds with certain definite objectives — hardiness
(for northern pecans), disease resistance, fruitfulness, size of nut (at
present a compromise), shell thinness, shelling quality, kernel quality.
The work of the Department is divided regionally; the Illinois Station
is carrying on a selection project; several private breeders are active;
and pecan breeding by selection is being conducted in New South
Wales and in Mexico.
Hickories other than pecans have received very little attention from
breeders — the market demand is too limited. Nature has accom-
plished considerable hybridization between the various species (pecan,
shagbark, shellbark, bitternut), and trees of some hybrid forms are
avadable commercially. Hickories superior in thinness of shell,
cracking quality, and flavor would fill a real need. A limited amount
of selection work is being done by the Department of Agriculture, the
stations in Illinois, Ohio, and New York (Geneva), and private
breeders.
Breeding the Persian walnut (called English walnut because it first
came to this country from England) has largely been confined to
selection, which has about reached its limit of practicability. The
next step is hybridization to develop varieties resistant to blight and
possessing greater fruitfulness, superior hardiness, better cracking
quality, and superior flavor. Such work is being conducted by the
Department, the Minnesota and New York (Geneva) stations, and at
least one private breeder. Selective breeding is being done in Mexico.
Selective breeding with the eastern black walnut is being conducted
by the Department, the Illinois, the Minnesota, the Ohio, and the
New York stations, and many private breeders. Similar work with
the Japanese walnut (much like the butternut) is being conducted by
the Connecticut station and several private breeders. The Depart-
ment is now starting a project to create a form of walnut unlike any
now existing by crossing the Persian walnut with the butternut for
hardiness and flavor, then with the eastern black walnut and the
Japanese walnut for sturdiness and fruitfulness of tree.
Almond breeding is being systematically carried on by the Depart-
ment in cooperation with the California station at Davis, with the
SUMMARY 149
objective of combining in a few new and definitely superior varieties
as many as possible of the superior characteristics of the existing
varieties. _ If this is successfully done, American almonds should not
only dominate the American market but have a place in foreign trade.
Practically no breeding work has been done with the pistache nut
(adapted to hot, dry regions), though it deserves attention. The
tung tree, the nuts of which furnish a valuable oil that dries more
rapidly and is more resistant to water than linseed oil, was introduced
into this country from China by the Department of Agriculture in
1905. The Florida Station began hybridization work in 1929, and the
Georgia Station began selective breeding in 1933.
Very little genetic analysis has been made with nut trees, but a
good deal of valuable technical work has been done on pollination
technique, pollen viability, receptivity of the stigma, fertilization, and
incompatibdity. ~
r J Flowers
The enormous number of our named varieties of flowers has re-
sulted from generations of breeding effort on the part not only of com-
mercial growers but of untold numbers of amateurs from every walk
of life. There are 15,000 varieties of roses alone, 8,000 varieties of
tulips, 7,000 varieties of dahlias, 7,000 varieties of narcissus. Many
of these are romantic in origin and testify to the deep love of the
breeder for his work.
Yet most of this work has been unscientific in nature, and too much
of it still is. Flower breeders, both amateur and professional, have on
the whole had only a slight acquaintance with the modern science of
genetics, which has played so important a part in the breeding of the
more important food crop plants. They proceed by trial-and-error
methods and wait for the breaks, and the result is much waste of time
and effort, and the persistence of practices that cannot bring the
expected results. Modern genetics goes out and makes the breaks.
The time has come when those interested in breeding flowers should
go to some trouble to study the facts and theories of heredity devel-
oped since Mendel's paper was rediscovered in 1900, and to master
the technical methods that have revolutionized other fields of plant
breeding. Genetics has a vast amount to contribute to the improve-
ment of flowers, though professional geneticists have paid relatively
little attention to ornamental plants except as these have been used
as laboratory material for the study of theory.
Flowers differ in their requirements for pollination, depending on
the structure of the flower parts and on different degrees of self- and
cross-sterility. Emasculation (removal of the anthers) is quite com-
monly necessary in cross-pollination, and the bagging technique must
frequently be used to prevent contamination with unwanted pollen.
The older method of improvement was by selecting superior plants
from a large mixed mass ; it is still widely used, but it is slow and very
limited compared with later methods. Then came line breeding, or
selection from the progeny of a single plant. Hybridization, the most
important method in plant breeding today, will probably be used
more and more with flowers; but what some flower breeders fail to
realize is the necessity for continuing the breeding work after the first
hybrid generation, to provide segregating groups with different com-
150 YEARBOOK, 1937
binations of parental characteristics; and. also the necessity for keeping
the right kind of records. Unusual plants produced by gene mutations
or by variations in the number, structure, or behavior of chromosomes
are sources of valuable material, and some of the newer methods of
artificially bringing about these changes seem promising for the flower
breeder. This emphasizes the need for an understanding of chromo-
somes, which has contributed definite practical results— notably, for
example, in the case of double-flowered stocks — and will contribute
much more.
Representative flowers considered are the amaryllis, China-aster,
canna, carnation, chrysanthemum, dahlia, gladiolus, hemerocallis,
iris, lily, nasturtium, rose, snapdragon, double-flowered stock, and
sweet pea. Some of these have a rich historical background and
several have been subjects for much patient selection and hybridiza-
tion. In two cases — the China-aster and the snapdragon — breeding
has been responsible for the development of forms resistant to de-
structive diseases. In all cases there are as yet untouched opportunities
for improvement through better breeding methods, a closer study of
inheritance and cytology, or the use of germ plasm not yet incor-
porated into our cultivated varieties.
Miscellaneous Forage and Cover Crop Legumes
Among the Cinderellas of the plant world are many humble le-
gumes— relatives of our common peas, beans, alfalfa, and clover — that
are valuable for soil building and conservation because they will thrive
where better-known crops fail, and they enrich the soil with nitrogen.
Some are known as weeds; some have been grown by farmers here and
in other countries both for forage and for human food. Not much has
been done to study the adaptability of these plants to special condi-
tions or to explore the possibility of improving them by breeding ; but
as this country passes out of the large spending stage in agriculture,
they will be given more attention. Their use is like having a savings
account in the bank.
A few of these plants are already of considerable value. The cowpea
is extensively grown, a large number of varieties are recognized, and
some State stations as well as the Department have carried on breed-
ing work with it. At least one outstanding variety, the Victor —
resistant to wilt and nematodes — has been developed by controlled
hybridization, and others have resulted from selection. The field
pea, also widely used, has given good results with selection and is now
the subject of breeding programs by the Department and by the
Georgia, the Alabama, and the Tennessee stations. The velvetbean
is a leading legume crop in the Southeast; several superior varieties
have resulted from selection over a period of years, and a breeding
program with this crop would probably be profitable. A large number
of species of vetch are in general use, and the Oregon station, cooper-
ating with the Department, has led in developing improved varieties.
The lespedezas or bush clovers, invaluable in southern agriculture,
have recently been receiving considerable attention. New varieties
have been introduced from Japan and Manchuria, and the Depart-
ment has been carrying on active selection work, but the possibilities
are by no means exhausted as yet. The bur-clovers are grown to
SUMMARY 151
some extent and have received some attention from breeders, but the
species has rich possibilities not yet explored. Rattlebox (crotalaria)
is a new forage plant in the United States, and the Department,
cooperating with the North Carolina, South Carolina, Georgia, and
Florida stations, has been selecting early varieties. Kudzu and the
peanut are grown as forage crops, but no breeding work has been done
with them from this standpoint.
Among the completely or almost completely neglected legumes,
some of which undoubtedly have potential value in the United States,
are the milk vetches for arid conditions; beggarweed or tick trefoil;
bonavist, long grown in Africa and Asia; the chickpea; fenugreek,
grown to some extent in California ; the grass pea and guar, both used
in India for animal and human food; kidney vetch, the subject of
breeding programs in Wales and Denmark; Lotus, commercially im-
portant in Europe and Australia; lupine, now being bred by German
and Russian workers; the pigeonpea, a valuable legume in tropical
countries; sainfoin, long grown in Europe; serradella, used in Europe
on acid sandy soils; Sesbania, adapted to wet soils in the South; sulla,
used in Europe and Australia.
Interesting technical studies with some of these plants, both in the
United States and abroad, have helped to develop fundamental
facts useful in breeding.
Miscellaneous Grasses
Man lives largely on grass. His grains are grasses. His meat and
milk are transformed grass; in the United States, grazing lands furnish
nearly half the sustenance of livestock. In addition, grasses are of
great importance in reducing erosion and maintaining soil fertility;
and this country spends over $100,000,000 a year on private lawns,
and some $90,000,000 on turf for other purposes. Systematic efforts
to improve grasses by breeding are therefore of major importance. In
the United States these efforts with the miscellaneous grasses are rela-
tively new; many State projects were begun not more than 5 years
ago — though sporadic work has been going on for a long time — and it
is too early to expect results. The work is older in Canada, the British
Isles, New Zealand, Australia, Sweden, Germany, Denmark;. and
probably more has been accomplished at Aberystwyth, Wales, than
anywhere else. But modern genetics proves that plants must be
bred for specific environments. We shall have to solve our own
grass-breedmg problems.
The sources of breeding material are as wide as the world, for each
region, from desert to swamp, from the Arctic to the Equator, from
mountain to sea beach, has its peculiar grasses, adapted to persist
and thrive there. The number of grasses developed under these
varied conditions is extremely large and the range in characteristics
correspondingly great. Long ago the migration of grasses to other
regions began. South American cattle live on forage grasses that
originated in tropical Africa, cattle in the Corn Belt on grasses from
Europe. The United States today may be divided into six regions
from the standpoint of climate, and the major types of grasses in these
regions into nine broad groups — Kentucky bluegrass, Canada blue-
grass, and timothy; the red top and bentgrasses; orchard grass and
152 YEARBOOK, 1937
tall oatgrass; Bermuda, Johnson, and Dallis grasses; carpet, Napier,
Bahia, and Para grasses; awnless bromegrass and crested wheatgrass;
native short grasses and prairie grasses; slender and western wheat-
grasses; Sudan, reed canary, and other grasses.
What are the needs and possibilities for improvement by breeding?
Shy seed production handicaps the use of many valuable grasses.
Diseases play havoc in certain regions and with certain types. Some
excellent grasses are not aggressive enough in growth to maintain
themselves in competition with other plants; others are too aggressive
to make possible the maintenance of desirable legumes in mixture.
Some are not vigorous enough in renewing growth after grazing or
cutting. For some pasture and range uses increased longevity is
needed, and this may be largely affected by drought resistance and
winter hardiness. Greater ability to thrive in wet and in saline soils
is very important in some places. Some good grasses would be more
useful if they were more palatable to livestock and had higher nutritive
value. In turf grasses, texture, ability to withstand hard usage, and
uniformity are of major importance. On all of these eight counts
there are sufficient variations within the best-adapted types to give
promise that breeding by selection or hybridization would accomplish
improvements. Already, selective breeding work in the United
States has furnished improved new strains, either introduced or soon
to be ready for introduction, of Washington and Metropolitan bent,
velvet bent, highland reed canary grass, tall fescue, tall oatgrass,
Bahia grass, tift Bermuda grass; and in Canada, of slender wheat-
grass, crested wheatgrass, bromegrass, and orchard grass. Twenty-
three additional improved strains in Canada are being increased for
more extended trials and distribution.
The manipulations in grass pollination by controlled methods are
often as fine as jeweler's work and must be performed under a magnifier
or microscope. Ingenious techniques have been developed, and much
study has been given to flowering habits, to the question of self
sterility, and to chromosome behavior, especially in wide crosses.
There has been little work as yet on the mode of inheritance of
characteristics. ~,
Timothy
Timothy, the most important of the agricultural grasses, was first
cultivated in North America, though it is of European origin. It
received its present name, presumably, from Timothy Hansen, who
introduced it into Maryland from New England or New York about
1720. In 1929, one- third of the total acreage in hay in the United-
States was all or part timothy. It is also widely used in pastures,
being one of the most palatable pasture grasses to livestock.
Varieties and strains of timothy differ rather widely in earliness or
lateness of maturity, length and degree of fineness of stems, width of
leaves, tendency for the leaves to remain green, resistance to the
principal timothy disease (rust), and in other ways. These variations
are the basis for breeding improved kinds. The objectives of breeding
programs include rust resistance, increased productivity, early varie-
ties for the South, late varieties for the North, varieties adapted for
hay production when grown in mixtures with clover or alfalfa, and
varieties especially suitable for use in pastures.
SUMMARY 153
Timothy is normally cross-pollinated, so that most of it is quite
hybrid in make-up. Methods of breeding include repeated selection
among open-pollinated strains, and also some self-pollination and
crossing of inbred lines.
Up to the end of the last century, timothy was timothy ; there were
no improved varieties, as there were of wheat, oats, and other grains.
In 1889, Willet M. Hays pioneered in making selections of timothy
plants at the University of Minnesota, for increased productivity and
a longer harvesting season. In 1894, A. T. Hopkins, a well-known
entomologist, began making selections and continued^ the work for
several years. Hopkins had a notable faculty for arousing enthusiasm
in others over the possibilities in timothy improvement.
After 1900, timothy breeding was started at Cornell University
and is still being carried on there. An early and a late variety, both
somewhat rust-resistant, have been produced, and a number of
teclmical studies have been completed. Other stations that have
had timothy breeding programs include those in Iowa, Minnesota,
Pennsylvania, Kentucky, New Jersey, and Wisconsin. Some breed-
ing work was conducted by the Department from 1899 to 1909, and
thereafter it was carried on more intensively in cooperation with
the Ohio Station. The outstanding variety developed from this work
is the Huron — late, leafy, rust-resistant— released in 1933.
Abroad, several varieties with regional adaptation have been devel-
oped at Svalof, Sweden, and at the Welsh Plant Breeding Institute,
Aberystwyth, Wales. Notable among Welsh developments were
low-growing types that root at the nodes, expecially suitable for
pasture. These have been tried only to a very limited extent in
the United States. Timothy-breeding work has also been carried on
in other European countries.
Technical studies with timothy include biometrical analyses of
yield trials, determinations of chromosome numbers, seed production
under self-pollination, self -sterility, and effects of selling on vigor,
yield, disease resistance, and other characteristics.
Alfalfa
Alfalfa, which means "best fodder" hi Arabic, is very old. One
writer has suggested that it was the "grass" on which Nebuchadnezzar
fed when he was driven into the fields. It was fed to sleek chariot
horses in ancient Eome. The Spanish conquerors of Mexico and
Peru took the Indians' gold but brought them alfalfa seed. Forty-
niners, sailing to California around the Horn, picked up some Chilean
alfalfa and took it with them. It soon spread to other Western States.
It did not winter well in the North. But in 1857 Wendelin Grimm,
a German immigrant, brought alfalfa from his homeland into Minne-
sota. For 50 years he stubbornly and patiently saved seed from
plants that survived the winter. In the end, he had the one hardy
alfalfa. Subsequently, experiment station workers made Grimm
alfalfa famous.
This was both a boon and a drawback. Grimm alfalfa was so
satisfactory that there was little incentive to develop other improved
varieties. Nevertheless, between 1903 and 1915 a number of State
and Federal workers were busy breeding alfalfa, and they did some
138004°— 37 31
154 YEARBOOK, 1937
interesting work introducing varieties that are now standard —
though the limitations of the methods they used were not then fully
understood. This work was stopped by the World War, with its
emphasis on food crops rather than feed crops.
Some years later, stands of Grimm and other alfalfas began
to die out prematurely and alarmingly, first in Iowa, Kansas, and
Nebraska, then in other Midwestern States. By 1925, Federal
workers traced the mysterious destruction to the organism now
known as the insidious phytomonas — Phytomonas insidiosa. Today
it costs farmers several million dollars a year in lost alfalfa crops
and expense of resceding. This catastrophe put pressure on breeders
to see what they could do.
Plant explorers of the Department have scoured the earth for
alfalfas, bringing back a thousand different strains. None proved
to be very resistant to the disease except some from Russian Turkistan,
northern India, western China, northeastern Iran. The chief problem
in the- present breeding program, then, is to combine the resistance
of these strains with the good commercial qualities found in Grimm
and other American alfalfas. Dovetailing with this is another
problem of developing strains especially well adapted to various
broad regions in the United States. Other desirable objectives
include heavier seeding, better forage quality, suitability for grazing,
insect resistance, drought resistance, and higher protein content.
For a concerted attack on these problems, State and Federal breeders
have recently organized the Alfalfa Improvement Conference, to
insure close cooperation between all the workers concerned.
Work has been done on breeding technique; correlations between
various characteristics in alfalfa; hybrid vigor; inbreeding and its
effects; the possibility of making species crosses; and segregating and
purifying strains for disease resistance and cold resistance, with the
object of recombining them. The general genetic behavior of alfalfa
has been explored, but little has been done on the inheritance of
specific characters. Recently a number of workers have been inter-
ested in the cytological study of the plant.
Soybeans
In the Orient soybeans have been grown since time immemorial,
and it has been said that some oriental countries could not exist
without them. The plant was introduced into the United States
(Pennsylvania) as early as 1804. Since 1890 most of the State sta-
tions have experimented with it, but it aroused comparatively little
enthusiasm until the last few years. In that time its rise has been
dramatic. Acreage has increased 110 times in 28 years, seed produc-
tion 13 times in 15 years. The United States is now second in seed
production to Manchuria, though still far behind that "Land of
Beans."
The reason for this phenomenon is to be found in the versatility
of the soybean. Every part of the plant is useful, and a tabulated
list of uses takes up a page of fine print. Forty-five oil mills in the
United States are now crushing soybeans; 40 concerns are manufac-
turing soybean food products; 75 factories are turning out industrial
products made from soybeans.
SUMMARY 155
Altogether, the Department of Agriculture and State stations
have brought in some 10,000 selections for testing and experiment.
Thirty-two stations and the Department are engaged in breeding
work. About 100 varieties have been introduced for commercial
growing since 1894. Yet the breeding work is only at its beginning,
for several reasons.
The soybean is very particular in its local requirements. This
means that special varieties for each kind of use have to be developed
for each separate region or locality. This has long been done in the
Orient. The uses themselves demand quite distinct characteristics.
Thus beans grown for oil should have a high oil content and a high
iodine number, which is associated with good drying quality. The
lecithin content of the oil is also important for some industrial uses.
Beans for certain industrial uses should have a high protein content.
Beans grown for food protein should be high in the three amino acids,
cystine, tryptophane, and tyrosine. Those grown to be cooked as
dried whole beans should be tender and of excellent flavor. Those
grown for use as green shelled beans must be especially adapted to
this purpose. And so on.
Progress has been made in developing varieties for local use that
meet these needs. But there is much still to be done. The breeder,
however, has a wealth of material, and the measurements and tests
already made indicate the range of some of the characteristics among
different varieties. Oil content, for example, ranges from 12 to 26
percent, iodine number from 118 to 141, protein content from 28
to 56, lecithin content of the oil from 1% to 3 percent; the percentage
of the amino acids mentioned varies over a wide range. The breeder
can choose and combine, build up this, reduce that. Diseases are not
yet a serious factor with soybeans in this country, but it is known that
resistance to several diseases varies also, and when that complication
enters he has some information on which to proceed.
The soybean is a self-fertilized plant, and artificial crossing is
difficult and tedious. Hybridization, however, offers the best means
of combining desirable characteristics and getting a wide variety of
segregates from which to make selections. The inheritance of a good
many characteristics of the flower, stem, leaf, and seed has been
worked out, and a beginning at least has been made in mapping the
location of a few genes on the chromosomes.
Clover
The ancient belief that clover brings luck has proved to be abund-
antly true for agriculture. First grown as a cultivated crop in the
sixteenth century, its use became the foundation for good farming
practice. It is at once food for the land and food for animals. Sys-
tematic improvement by breeding, a recent development, is bemg
carried on in several countries.
Natural adaptation has been the prime factor in developing regional
strains of red clover — the most important of the clovers in the United
States — that differ in productivity, winter hardiness, and disease
resistance. For several years, these regional strains have been closely
studied by the Department in cooperation with the Kentucky, Ohio,
and Iowa stations, partly to determine regional needs, partly to dis-
156 YEARBOOK, 1937
cover superior plants that may be used in breeding. Broadly, the
chief objectives for the three red-clover regions of the humid eastern
United States are: Southern — disease resistance, especially to anthrac-
nose; central — disease resistance and winter hardiness; northern —
ability to withstand a long period of winter dormancy. In addition,
powdery mildew, the potato leafhopper, and the clover root borer arc
clover enemies in all regions.
So far, anthracnose-resistant strains have been developed by the
Tennessee and Kentucky stations, and the Department of Agricul-
ture has during recent years cooperated in improvement of the strains
developed by the Tennessee station many years ago. Lines resistant
to powdery mildew have been developed in cooperation with the
station in Wisconsin. Other developments are in progress in cooper-
ation with the Illinois Station; and the stations in Minnesota, Penn-
sylvania, Tennessee, Indiana, New Jersey, and Idaho have red clover
breeding programs under way. Abroad, nearly all European coun-
tries, and Australia and New Zealand, are doing breeding work with
red clover, and in several of these countries superior strains have
been introduced. Selection from natural stocks has played a large
part in improvement programs, but the isolation of self-fertile lines
and controlled crossing are also used. The Welsh Plant Breeding
station has carried on important basic studies.
There has been no breeding work with white clover in the United
States, but work has been done in New Zealand, Denmark, Sweden,
Finland, and Wales. Crimson, alsike, subterranean, berseem, and
Persian clovers have not been bred in this country, though some of
them have received attention abroad.
Sweetclover, which was classed as a weed a few years ago, has had
a phenomenal rise in popularity and now holds an honorable place in
the agriculture of the north-central region and the Great Plains
States, as well as in several foreign countries. Several varieties,
resulting from selection and introduction from abroad, have been
introduced by the Department of Agriculture, by several State sta-
tions, and by individuals. Canada leads in systematic breeding, and
work is also in progress in Wisconsin, Minnesota, Kansas, Washing-
ton, Texas, Nebraska, Illinois, West Virginia, and Idaho, as well as
in the Union of Soviet Socialist Republics and in Germany. One of
the chief objects in all breeding studies is the development of strains
low in coumarin, since the presence of coumarin or of closely related
substances appears to make spoiled sweetclover hay toxic to livestock
and lowers the palatability of the green plant. So far, the results in
this direction are promising.
Studies have been made of fertility and sterility relationships in
clover that have cleared up misconceptions, and pollination tech-
niques have been developed. There have been some cytological
investigations and genetic analyses, especially in sweetclover.
Hops
Beer is made with hops, water, malted barley and other cereals.
The hops supply lupulin (resins and essential oils) which gives the beer
its characteristic flavor, and tannins which help to clear it. Thus hop
growing is vital to the brewing industry, though unfortunately for
SUMMARY 157
growers, a small quantity of hops makes a great deal of beer. In
Europe hop growing goes back at least to 768 A. D. Kings who liked
hopped beer sometimes compelled farmers to grow hops by law; those
who preferred beer without hops forbade farmers to grow them.
Kings of the latter type were apparently in the minority, and in
Europe much effort was devoted to improving hop varieties.
The hop is a peculiar species. It is a perennial vine, grown on poles
or trellises, and extremely sensitive to sun, wind, heat, rain, insects,
and diseases. Male and female flowers are borne on separate plants,
though it is not unknown for a plant to change its sex, sometimes more
than once. The hop of commerce is something like a fir cone but more
papery and fragile, and it is borne only on the female plant. Fertiliza-
tion is not necessary for the development of the hop, but the cone
bears seeds only when the flowers are fertilized.
Commercially hop vines are repoduced by cuttings, like sugarcane
and some other plants. Since the seed is always a product of cross-
fertilization, the plants are of hybrid origin genetically, and seeds from
the same mother will produce many different types. It is chiefly from
these diverse seedlings that hop breeders get their raw material for
superior selections. Hop breeding presents some especially knotty
problems and has some difficulties similar to those of animal breeding.
Because the male plant bears no cones, it is uncertain just what it
contributes to improvement, even when controlled pollination is
practised so that the nature of the male parent is known.
Breeding work in the United States is relatively new. It was
started by the Department of Agriculture in 1900, but later the World
War discouraged and prohibition finished it. Now, however, it is
being continued again in cooperation with the Oregon station. The
chief objectives are increased yield; favorable periods of maturity:
resistance to several diseases, especially downy mildew, the bane of
growers in various sections; and quality, an elusive character depend-
ing on type, color, soundness, and lupulin content. Of these, only
the amount and quality of lupulin can be accurately measiired by
laboratory methods. The importance of quality may be better under-
stood from the fact that at present brewers in this country frequently
mix some European hops with their American-grown hops and usually
pay a high premium for hops from Germany and Bohemia.
Thus far the breeding program in the United States has been con-
cerned largely with making a close study of the available raw material
so that an accurate catalog of plant characteristics may be available.
It has been necessary to work out techniques for some of the more
difficult problems such as control of pollination, evaluation of breeding
methods, controlled development of the downy mildeAV disease, meas-
urement of resistance, and determination of quality. With these
difficulties on the way to solution, a basis is being laid for future breed-
ing work. Good results with seedling selection in Europe indicate the
possibilities, though improved European varieties have failed to give
comparably good results in this country. Growers on the Pacific
coast are now very much interested in hop improvement by breeding,
and the New York (Geneva) station has also recently initiated a
varietal improvement project.
158 YEARBOOK, 1937
Forest Trees
In forestry, genetics is almost a new word, and breeding as it is
practiced with other economic plants is a virgin field. Economic
pressure in the wood-using industries and the urgent national need to
build up forest areas, however, have turned attention to tree breeding
as a vital part of an intelligent forest program. There is ample evi-
dence that, like other plants, forest trees differ individually in the
characteristics that are of value to man; and the possibility of breeding
superior individuals and populating large areas with their descendants,
as is done with wheat and other crops, is one we cannot escape
exploring.
Obviously there are difficulties not involved with small, quick-ma-
turing plants, in many of which pollination is fairly easily controlled,
and it will take a good deal of study and ingenuity to overcome some of
these difficulties. The methods and possibilities, however, are funda-
mentally the same as with other plants. They include a clear formula-
tion of the type of tree desired for a given use; the selection of superior
individuals by extensive testing and observation; establishing pure
lines where possible; as much use of vegetative propagation, by cut-
tings, etc., as possible, to reproduce superior individuals absolutely
true to type; the crossing of strains, varieties, species, and genera, both
to creat new types and to obtain hybrid vigor; a thorough study of
polyploids — that is, individuals with an increased number of chromo-
somes in the cells beyond the normal number — as sources of especially
valuable stock. At present, polyploids are receiving special attention
because these plants with extra chromosomes are so often character-
ized by unusual size and vigor, but the enlarged cell size in some types
of polyploids, resulting in coarseness of structure, may prove to be a
drawback for many commercial uses.
It need hardly be said that research in the cytology of forest trees,
particularly in cytogenetics, and in the mode of inheritance of char-
acteristics, should be carried on along with a practical program.
Much work is also needed to determine standards and tests applicable
in the forest and in the selection nursery.
In every one of these fields, a beginning at least has been made.
Fairly extensive tests are being conducted to determine superior varie-
ties and individuals for both regional forest requirements and use
requirements, and these tests include disease resistance, weather
resistance, rapidity of growth, and other important characteristics.
Hybrids, superior in various ways to either parent, have been made, a
notable example being the creation of fast-growing poplar hybrids for
paper pulp. Experiments are being carried on in methods of control-
led pollination and vegetative propagation. Efforts are being made
to devise better progeny tests — not an easy matter under practical
forest conditions — and ways to reduce the time involved in testing.
Perhaps the least work is being done in fundamental research in
genetics; but so far there are very few geneticists in forestry — practi-
cally none in comparison with other branches of agriculture. '
To other plant breeders the amount of breeding work in forestry
would seem small indeed, and doubtless quite elementary in nature.
Nevertheless, the foundations necessary for a science of forest genetics
SUMMARY 159
are being laid, in the United States and m other countries. More-
over, the forest-tree breeder, challenged as he is by difficulties, is in
the stage where he is filled with enthusiasm for the possibilities not
only of eliminating some of the most costly mistakes of past forestry
practice, but of adding something genuinely valuable to nature's
own magnificent achievements in creating trees useful to man.
Angora Goats
The goat performs two useful functions. It cleans up brush,
thereby saving its owner a great deal of work; and through its diges-
tive processes, it converts the brush into food and clothing for man,
in the form of milk, meat, mohair, and skins.
The domestic goat is probably descended from the pasang or Greek
ibex of the Near East. The long-haired Angora was originally
developed by the Turks centuries ago. The first importations to
Europe were apparently made in the sixteenth century, and to the
United States as late as 1849. South Africa, Turkey, and the United
States are the leading producers today. There are now over 3 million
Angoras in this country, and the industry is concentrated chiefly in
the Southwest, with Texas well in the lead. Of the 15 million pounds
of mohair produced in the six leading States in 1935, Texas produced
13 million.
Improvement of the Angora goat has been entirely in the hands of
private breeders. In the range herds, it has been carried on by the
method of breeding high-grade does to registered bucks that conform
to the standards of the breed association. Very little research work
on breeding or genetics has been done by public institutions. The
Texas station has been the leader in this field, and at its branch
station near Sonora it is now carrying on three active projects on
inheritance of type, inheritance of cryptorchidism or undescended
testicles, and cytological and hybridization studies.
The best present representatives of the breed produce up to 75
percent more mohair than the average for the country. But there is
a very great lack of uniformity even in good herds. If further progress
is to be made, a research^ program will be needed to work out better
methods than those now in use to determine an animal's inheritance,
and a far better knowledge of the mode of inheritance of characters
concerned in the production of good fleeces. Research usually pays
well, but there are many difficulties and complications involved in
such a program, and it can only be carried on with the active encour-
agement of the industry.
Meanwhile certain practical steps might be taken by the industry
that would tend in the right direction. Among these would be a
system of pedigree recording based on production of mohair, with
certification of the records, as with dairy cattle and poultry; the
selling of mohair on a quality rather than a weight basis, to stimulate
improvement of the breed from this standpoint; and the adoption of
different methods of awarding prizes at shows, on the basis of get
of sires and outstanding families rather than individual appearance —
a practice that would be in line with the use of the progeny test,
which is overwhelmingly important in evaluating breeding stock,
whether plant or animal.
160 YEARBOOK, 1937
Milk Goats
The milk goat is a handy pocket edition of the cow, and it will
subsist where the keeping of cows is impracticable. In certain areas
and under certain economic conditions, it can be an important factor
in contributing to the family food supply. The milk is not significant-
ly different from cows' milk in nutritive value, and goat meat is
palatable and wholesome. The official maximum production record
in the United States, made by a Saanen doe, is nearly 7 quarts a day
for a period of 9 months and 10 days. Average production is very
much under this, and there is great variability between individuals.
Efforts to improve the productivity of milk goats in the United
States, therefore, are worth while not only from the standpoint of the
present industry, with its breeding and dairy investment, but also as
one method of economically raising the nutritional level of some
sections of the population.
In this country, only two projects have been carried on by public
agencies involving research and experiment in milk goat breeding —
one conducted by the Department, one by the New Mexico station.
The Federal project was started in 1909. It has consisted largely
in grading up common American does by crossing and top-crossing
with registered Saanen and Toggenburg bucks. Progress has been
slow partly because of the very small number of breeding does used.
However, the average length of the lactation period has been increased
145 percent over that of the native does, and the average annual milk
yield by 385 percent. Analysis shows that the period of maximum
production is between 4 and 6 years of age. Index measurements of
the sires used show marked differences in ability to transmit superior
inheritance to daughters.
At the New Mexico station, native does have been graded up by the
use of registered Toggenburg bucks, and studies have been made of
the inheritance of horns and wattles, length of gestation, prolificacy,
sex ratio, and the effects of inbreeding and outcrossing on milk pro-
duction and birth weight of kids. Marked increases in production
were obtained from the top-cross does, and several does in the herd
have made creditable records under advanced registry. Line breeding
was practiced with three outstanding bucks, the results indicating
that it would be worth while to continue this as an experimental
procedure. Fertility in the herd was high, 144 parturitions producing
286 kids.
Other researches with milk goats include nutritional experiments
with the milk and studies on the physiology of milk secretion, includ-
ing the effect of pituitary extract on lactation. There has also been a
limited amount of genetic research on inheritance of horns, wattles,
short ears, color, cryptorchidism, multiple births, and a peculiar
nervous instability.
Improvement of herds has been mainly in the hands of private
breeders and their three registry associations. Considerable progress
has been made, but more might be done by the keeping of more com-
plete records; the development of a more extensive record-of -perform-
ance program; the more extensive use of proved sires through a
system of exchanges; the elimination of factional tendencies among
SUMMARY 161
groups of breeders; and the working out of better procedures for the
selection of breeding animals. There is a need also for further re-
search and experiment on the uses of goat products, and for more
study of the economics of production.
Dogs
Dogs supplement the brains of men. Their usefulness depends
almost entirely on intelligence and temperament. No other animal
serves so many purposes; they are hunters, guards, companions,
guides, messengers, herders, detectives, haulers and carriers, scaveng-
ers, and even, in parts of the world, sources of fur and food. It is
surprising, then, that so little has been done in the way of systematic
research in the genetics of the dog, in spite of the fact that in other
fields — physiology, psychology, medicine — work with dogs has helped
to make possible some major scientific advances of great benefit to
humanity.
Scattered studies have furnished information on the inheritance of
coat colors, which apparently depend on many genes, often with
multiple effects. Certain characteristics of form and structure have
also been studied, including the inheritance of modified secretion of
the endocrine glands, which has been under investigation by Stockard
at the Cornell University Medical College. Some work has been done
on the inheritance of aptitudes, notably at Fortunate Fields, in
Switzerland, where German Shepherd dogs have been trained as
guides for the blind and for army and police service. Here marked
progress has been made in breeding superior animals by assuming that
valuable characteristics were controlled by a few major genes.
In practical breeding, dog competitions of various kinds have had
a marked influence, since persistent winners at field trials and dog
shows have a favored position as breeding stock. On the whole, this
has probably been a good influence in dog breeding, though from the
standpoint of sound scientific practice undue weight is given to the
appearance or performance of the individual animal. Awarding
prizes and selecting breeders on the basis of a genuine progeny test
would put dog breeding on a sounder genetic foundation.
In some cases these contests have been responsible for splitting a
breed in two different directions, one strain being especially adapted
to perform well in the field, the other being notable for show points.
The field competitions — greyhound racing, dog-sled racing, hunting
and retrieving contests, sheep-herding contests, obedience trials — are
of interest as indicating certain kinds of measurements that would
have to be developed in a program of genetic research so that one dog
might be accurately compared with another.
What are the possibilities in genetic research for the future? There
is little doubt that it would help to accomplish improvements in dogs
themselves, especially in the development of types for special pur-
poses. Beyond this, however, is the fact that dogs are probably
better suited than any other animal for investigations in the inheritance
of psychological traits. These traits are important in many farm
animals; nothing is known about their behavior in heredity. The
Department of Agriculture has recently made a modest beginning in
an investigation of this sort, using the Puli dog — a sheep dog of
162 YEARBOOK, 1937
Hungary — which is being crossed with various other breeds. From
these experiments it is hoped that worth-while information may be
developed regarding the inheritance of intelligence and certain apti-
tudes of practical value in dogs, the influence of temperament in such
problems as effective feed utilization, and the possibilities for similar
investigations with other farm animals.
Turkeys
Before the nineties, this country produced turkeys at the rate
of 1 a year for every 5 persons. In subsequent years the blackhead
disease, scourge of turkey growers, reduced this to 1 for every 15
persons. Recently research taught us how more nearly to control
blackhead, and the number of turkeys has now risen to 1 a year
for every 6.5 persons. But less scientific attention has been paid
to breeding problems than to those of feeding, management, and
disease control.
Our modern domesticated turkeys are descended from the North
American or common wild turkey, of which there are five subspecies.
Wild turkeys were apparently domesticated by the American Indians,
and some of them were taken to Spain as early as 1498. Several
European domesticated varieties were developed from this ancestry,
and some of these were brought back to the colonies to become the
foundation stock of our six present American breeds — the Bronze,
the Narragansett, the White Holland, the Bourbon Red, the Black,
and the Slate. The differences between these breeds are largely in
plumage color.
Several major objectives stand out as desirable in turkey breeding,
though little in the way of coordinated or intensive work has been done
toward achieving them. (1) There is an increasing demand for a
smaller bird to meet the needs of the average family. Hitherto,
breeding has tended toward increased size. There is still a demand
for large birds for hotels, etc., but they now actually sell at a discount
because of the greater demand for smaller sizes. This situation can
be corrected by breeding (2) There is need for improved body type
to provide a larger proportion of meat to bone, especially on legs and
breast. (3) Birds should be bred to reach market maturity at an
earlier age. (4) Higher egg production is desirable, especially in
making possible an earlier and longer laying season, which now
covers a maximum of about 6 months. (5) Higher fertility and
hatchability of eggs are desirable to reduce production cost. (6)
Attention should be given to breeding for lower mortality, whether
from disease or other causes.
In achieving such ends, use might be made of a breeding system
based on production records, pedigrees and, progeny tests, such as
that now used by progressive breeders of chickens. There is need for
more trap nesting and pedigree recording to serve as a basis for iso-
lating superior families and breeding from them. State and Federal
agencies might well lead the way by developing strains notable for
viability, quick maturity, and good market quality.
The small amount of genetic research with turkeys at State stations
has been concerned with tracing the inheritance of plumage colors.
The Department has experimented in making crosses between tur-
SUMMARY 163
keys and chickens. All the hybrids died as embryos, though one lived
almost to the hatching state. At its range experiment station in
Montana, the Department carried on a 5-year inbreeding project
which indicated the possibility of establishing inbred lines not inferior
to outbrod turkeys in fertility, hatchability, production, and weight
of eggs. A similar outbreeding project was successful in improving
fertility, hatchability, and production of eggs, and maintaining egg
Weight- * Ducks
There arc places along the South Shore of Long Island, N. Y.,
where for many miles the air is filled with the quacking of ducks, and
the creeks and small coves are white with the birds. This is the center
of the commercial duck industry. The flocks are all Pekins, which
are sold as "green ducks" at the age of 9 to 13 weeks, after a period of
rapid fattening. Elsewhere in the country there are a few commercial
duck farms, and ducks are raised as a side line on farms in every State.
The Pekin is everywhere the outstanding breed, though the Rouen,
Aylesbury, Cayuga, and Muscovy are also represented among the
meat breeds; the Indian Runner among the egg breeds; and the White
Call, Grey Call, Black East India, Mandarin, and wood duck among
the ornamental breeds.
In the United States little has been done in the way of scientific
duck breeding. Yet the best commercial flocks are remarkably uni-
form in the size and quality of the market birds, and remarkably
efficient in fattening under good management; in 12 weeks they in-
crease their weight 50 times. This uniformity may be in part due to
the small number of Pekins in the original importations, from which
nearly all the ducks of this breed are descended. As compared with
chickens, the degree of inbreeding would be comparatively high, which
would tend to make for homogeneity.
Duck breeders still rely entirely on their ability and experience in
selection, and have not resorted to trap nesting, progeny testing, and
the keeping of individual pedigree and production records. Mass
matings are used exclusively, and the breeding birds are kept for only
one laying season, on the ground that young birds lay earlier and are
more prolific. These conditions preclude the keeping of individual
records or the making of individual tests. Experimental inbreeding
or cross-breeding is negligible or lacking, though the Aylesbury is
sometimes crossed with the Pekin in England, and the mule duck, a
cross of the Muscovy and the common domestic duck, is occasionally
seen in this country.
In England trap nesting is practiced with the egg-la,ying breeds,
and in the 16 years since individual records have been kept there has
been great progress in improving egg production. The highest indi-
vidual production runs over 360 eggs in a year, and there are many
records of over 300 eggs. In egg-laying contests the average produc-
tion per pound of body weight is much greater than is the case with
chickens.
Ducks offer a virgin field for poultry-breeding research, especially
in the inheritance of meat characters, since they are chiefly used for
meat in this country. The same general principles should apply here
as apply in the case of chickens. Research of this nature, however, is
164 YEARBOOK, 193 7
not likely to be undertaken except in response to definite needs felt
and expressed by those concerned in the industry.
Fur Animals
Breeding and genetic research is important in two ways in the
conservation and improvement of fur resources. First there is the
problem of maintaining the wild fur resources of the United States.
There was a time when this country was the world's chief source of
furs. Fortunes were made in the fur trade. Partly because of the
lavish exploitation of fur animals, we no longer supply more than a
third of our own needs. Meanwhile our demand for furs has increased,
and little is done to conserve the fur animals we have left. An intelli-
gent conservation policy requires, among other things, much more
knowledge than we now have of the breeding habits and gestation
periods of the animals in the wild. Studies of the marten made by
the Bureau of Biological Survey, for example, show that this animal
has a gestation period of 9% months. This means that under any
ordinary system of closed and open seasons, it would rapidly become
extinct; in order to save the martens, it is necessary to prohibit trap-
ping for several consecutive years. Similar accurate information on
wild fur animals other than foxes is practically nonexistent.
The second need for research is in connection with the produc-
tion of fur animals on farms. This is a rapidh* growing industry
in which an increasing number of farmers engage as a part-time
enterprise. It is relatively very young, but it has now passed the
early speculative stage and is settling down to a healthy basis. In
1923 the total value of silver fox pelts was less than $820,000; in 1936
it was over $8,000,000.
Fox farming has reached the stage where it needs the same kind of
help from science that has long been given to other livestock industries.
There is little in the way of a well-thought-out or scientifically tested
procedure in present breeding practices. At the same time, fur color,
which is the primary factor from the market standpoint, lends itself
particularly well to inheritance studies and genetic analysis. A re-
search project begun in 1928 by the Bureau of Biological Survey
indicates what may be done in this direction. That study was an
attempt to find out how the major types — the red fox; the standard
silver fox, a mutation that occurred in Canada ; the Alaska silver fox, a
mutation that occurred in Alaska; and the cross fox, a hybrid between
red and silver — behave in inheritance. Two pairs of genes, A, a, B, b,
apparently accounted for these variations in color; and in breeding
experiments, supplemented extensively from records of matings made
by fox farmers, this genetic hypothesis worked out with remarkable
accuracy, so that it was possible to tell, by referring to a genetic chart,
just what results any given combination would give in a large popu-
lation.
The Bureau is now engaged in a project to determine the inheritance
of degrees of silvering in the pelts, since this is the fundamental basis
of market classes. Both studies, however, have been limited by the
small amount of funds available for such projects. There is need for
more extensive research on this and other aspects of fur animal breeding
by public agencies, both Federal and State.
SUMMARY 165
Bees
The individual bee has such a painful and distracting way of making
its personal importance felt that probably few of its victims have ever
realized that in the United States bees are also the nucleus of a 35-50-
million-dollar beekeeping industry, or that they give us much of our
food supply by fertilizing blossoms. Both facts underscore the
importance of breeding better bees.
The bee breeder, however, has a peculiar and in some respects an
exceedingly difficult task. For example, he is confronted by at least
five factors not faced by the breeder of other farm animals. (1) Bees
mate in midair, and until recently it was impossible to make con-
trolled matings, except in an uncertain way through the use of isolated
mating yards. (2) The drone is produced by virgin birth and there-
fore receives its inheritance entirely from its mother. (2) The drone
dies immediately after mating, and the queen mates only once in her
lifetime; therefore their use in line breeding has been impossible.
(4) The worker bee, which does the work of gathering and storing
honey, is not fully developed sexually and therefore cannot be bred
for a direct study of its inheritance, although it does at times produce
males by virgin birth. (5) Identification of individuals and even
races of bees often depends on very small points, which must be
measured by special methods.
As a groundwork for breeding, it has been necessary (1) to study
sex physiology and functioning, and (2) to develop physical measure-
ments that can be used for identification.
The greatest hurdle was passed when methods were developed
within recent years for artificially inseminating queens. This is
now done in three ways — by taking spermatozoa from the male
and introducing them into the female with a tiny syringe; by bring-
ing about a compulsory mating between a queen and a drone, both
held under constraint; or by removing the sex organs of the drone
and inserting them in the queen. The first two methods were
developed in the United States, the last in the Union of Soviet
Socialist Republics. All three now involve the use of a microscope
and delicate instruments. A limited approximation to line breeding
may even be made by removing spermatozoa from a fertilized queen
and introducing them into a daughter of the drone from which they
originally came.
It remains to develop a technique for controlled mating under more
natural conditions.
Progress has also been made in cataloging traits that will be useful
in identifying individuals, tracing the effects of inheritance, and
measuring colony behavior.
Meanwhile, without waiting for the uncertain appearance of useful
mutations or for an exhaustive study of inheritance, the bee breeder
is in a position to go ahead toward the goal of producing a bee better
adapted to the needs of agriculture. He has several traits available
in the germ plasm of the common black, Caucasian, Carniolan, Italian,
and Cyprian races that it should be possible to combine — long tongue
to reach deeper sources of nectar, gentleness, the tendency to make
white comb cappings, reluctance to swarm, resistance to European
166 YEARBOOK, 1937
foulbrood and to common hive enemies, industriousness, and uniform-
ity of body markings.
Some interesting but inconclusive work has been done on the
ctyology of the honeybee. Genetic research has been scanty, but the
inheritance of some characteristics has been studied, dominance and
recessiveness has been determined for a few factors, and a few linkages
have been worked out. It is known that Mendel worked with honey-
bees in his effort to determine the fundamental laws of inheritance,
but unfortunately his notes have been lost.
Fundamentals of Heredity
Reproduction by means of sex involves the union of two cells, a
male and a female, each of which carries a set of chromosomes con-
taining large numbers of genes that determine hereditary characteris-
tics. For example, when two parents with contrasting character-
istics have been bred pure, the first generation resulting from their
union has all the chromosomes and therefore all the genes of both
parents. If a plant of this generation is selfed (the closest possible
inbreeding), the characteristics of the original parent will begin to
assort or segregate into groups among the offsprings of the second
generation. The chromosome mechanism is such that all possible
combinations come together if the number of second-generation off-
spring is large enough.
Thus beginning with the second generation, most of the progeny
are not like either original parent but have different combinations or
groupings of characteristics from both of them. In this wealth of
new combinations of genes derived from two selected individuals,
the breeder finds the particular combination he is looking for — or
something that approximates it.
The segregation of characteristics occurs in definite ratios, first
discovered by Mendel. They can be worked out mathematically
from the fact that all possible combinations occur in a large number
of progeny, but Mendel worked them out by observation and thereby
found the clue to this fundamental law of inheritance.
A knowledge of the segregation ratios gives the breeder the clearest
possible insight into the actual behavior of characteristics in inheri-
tance, and in addition these ratios are of practical value in a number
of ways. There are a great many different ratios because the effects
of dominant and recessive genes, and various gene interactions, bring
about many modifications of the basic numbers. The typical ex-
amples can be readily understood by patiently following, step by
step, what actually happens in inheritance.
Other concepts constantly used by the breeder include linkage (the
location of certain genes in the same chromosome), crossing over (the
exchange of segments between two paired chromosomes), sex linkage
(location of genes in the sex chromosomes), and mutations. All of
these help to explain what actually occurs in nature and to define
what the breeder can expect and what he cannot expect to accomplish.
Animal breeding does not lend itself to the same kind of neat and
definite analysis for several reasons: (1) Selfing is impossible, and the
closest inbreeding does not approach that in plants. (2) More prog-
eny are required for many genetic analyses than can usually be
SUMMARY 167
obtained with animals. (3) Most valuable characteristics in animals
are quantitative (amount of milk produced, etc.), and such character-
istics usually depend on relatively large numbers of genes interacting
in complex ways. Nevertheless, there is an abundance of proof that
animal inheritance works just like plant inheritance, and the basic
concepts of genetics have been of enormous value in clarifying and
improving animal-breeding methods. Even though the animal breeder
will probably never be able to make the fine-spun analyses possible
for the plant breeder, the newer knowledge of genetics is already
reflected in animal-breeding practices, and it will undoubtedly make
for more certain and more rapid progress, and fewer costly errors, on
the part of those who will take the trouble to understand it.
Vegetative Reproduction
When plants are reproduced by means of cuttings, buds, tubers,
runners, rattoons, or other vegetative parts, the breeding situation
is different than when reproduction is by means of seeds.
A seed results from the union of two cells, male and female. Even
if these come from the same flower or the same plant, many of the
male and female cells will contain different chromosomal material
unless the plant has been bred pure so that all its male and female
reproductive cells have identical chromosomes. The differing chro-
mosomes will be divided up among the progeny in such a way as to
produce different types of individuals.
In reproduction by means of vegetative parts, there is no union of
sex cells, and each new plant has precisely the same chromosomes as
the plant from which it came. Exact copies of the original parent
can be reproduced for any number of generations. Winesap apple
trees have been reproduced by budding or grafting for many genera-
tions, and theoretically every Winesap tree today is exactly like its
original ancestor of 200 years ago. Thus by the use of vegetative
reproduction, all the trouble of "purifying" a strain is eliminated.
Even the most mixed hybrid reproduces true to type. When this
method is feasible, then, it is often a valuable short cut, especially
where it is difficult — as in the case of many forest trees — to obtain
true-breeding material from seed.
But occasionally the new individual is not exactly like the parent.
Rarely, there are mutations in one or more genes in a vegetative
cell, or some unusual behavior of the chromosomes, that make a part
of the plant different from the rest. Usually this occurs only in one
case out of several thousand. When the new form is valuable — as
has been the case with some of the bud mutations of tree fruits — it
too can be multiplied by means of vegetative reproduction.
# On the other hand, this very ease of exact reproduction has limita-
tions. The true genetic make-up of the breeding material is neglected ;
there is no need to know it, as there is in inbreeding and cross-breeding.
Yet it is through the diversity of forms brought about by combining
different chromosomal material that the modern breeder gets valuable
additions to our economic plants. If he desires to make planned
improvements, he must resort to seed production even with those
plants that normally are reproduced by vegetative means. This has
been amply proved, for example, in the case of potatoes and straw-
168 YEARBOOK, 1937
berries. By combining chromosomes, the breeder deliberately creates
what he desires. When he uses vegetative mutations, he merely
waits for nature to produce something that will be useful to him,
trusting to trained observation to* find it.
Do plants reproduced by vegetative means for many generations
tend to run out or be weakened for the battle of survival? This has
long been a popular belief. It may be said flatly that there is no real
evidence that running out occurs. Where plants seem to run out it
has been found in every case that the deterioration has been due to a
virus disease or some other definite cause.
New Studies in Chromosomes
By studying the architecture of the molecule, chemists have been
able to achieve marvelous results in synthesizing nature's products in
the laboratory. How far geneticists may be able to go in this direction
is not yet known, but new advances seem to be foreshadowed in the
researches now being made on nature's methods of juggling chromo-
somes. Intensive study of the jimsonweed has been fruitful of
knowledge in this field that may prove to have significant applications
to breeding work with plants of economic value.
The present-day Mendelian analysis of inheritance, with its domi-
nant and recessive traits, assumes that chromosomes go in pairs in
the body cells. It is now known that they do not by any means always
go in pairs. Rarely, there is only one of each kind instead of a pair.
More frequently there are three or four of each kind, or even more.
In some genera of plants, this arithmetical multiplication of chromo-
somes may run in a regular series, different species being characterized
by different numbers of chromosomes in the set, though all the species
in the genus have the same number of sets. This regular increase
gives rise to what are called balanced chromosomal types, since the
balance between the sets is maintained in spite of the additions.
But there are also unbalanced chromosomal types in which only a
single set has an extra chromosome or chromosomes added to it. The
balance within the cell is then disturbed ; there is an excess of the mate-
rial contained in the extra chromosome. Sometimes a complete
extra chromosome or two is added to a set. Sometimes two identical
half-chromosomes are added, joined together like a worm with a head
at each end and the tails missing. Sometimes the addition is half of
one chromosome and the opposite half of a chromosome from a
different pair, joined together like a head and a tail from different
worms. And so on.
Detecting this kind of jugglery within the cell might be interesting
but academic if it were not for the fact that chromosomes carry the
determiners of hereditaiy characters. Careful observation in jimson-
weed shows that each of these changes results in specific alterations in
the characteristics of the plant, both qualitative and quantitative.
Large numbers of such changes have been classified and correlated
with the addition or subtraction of whole chromosomes or different
parts of chromosomes. The differences between races of jimsonweed
m different parts of the world have been found to be due to rearrange-
ment of chromosome material. In this way new lands of chromosomes
SUMMARY 169
have been produced, which have been used in building up now kinds
of jimsonweeds. Types can be arranged in a regular series, and what
effects will be produced by deleting or adding certain chromosome
material can be predicted in advance.
From a practical standpoint, the significance of this lies in a possible
increase in the controlled synthesis of plants of desired types. It
suggests a somewhat different operation than that based on the usual
analysis of unit factors alone. Cytological examination shows that
many of out most valuable plants are characterized by unusual
chromosome numbers of one kind or another. Can we repeat these
deliberately, or bring about new and different additions and sub-
tractions of chromosome material that will have significant effects?
The experimental production of extrachromosomal types in jimson-
weed is promising. Not the least interesting part of it is the fact that
by suitable laboratory treatment of living cells such changes in
chromosome material can be made to occur far more frequently
than they do in nature.
Chronology of Genetics
The modern science of genetics is a fusion of several sciences and
practices that for a long time developed separately — animal breeding,
plant breeding, cytology, or the science of the microscopic cell, and
certain branches of mathematics. If today men not only dare to
dream of emulating and surpassing nature by creating new, improved
forms of life, but actually do it on an ever-increasing scale, it is because
they have a rich store of facts and theories on which to base their
work — facts and theories contributed by patient researchers in many
countries over many generations.
Both animal and plant breeding of a practical nature, of course,
are very old, but all of the early work was hit-or-miss and uncertain,
since it was not based on adequate knowledge. The first great mile-
stone in modern genetics was the announcement by Camerarius of
Germany in 1694 that plants reproduce by the union of male and
female cells. This suggested deliberately uniting two different kinds
of plants and was followed by the hybridization work of Fairchild in
England about 1717, and of many others after him. It was not long
(1727) before hybridization was put to commercial use by the Vil-
morins in France, and by 1840 they were actually using a kind of
progeny test. In 1859 Darwin put biological science on an experi-
mental basis with his Origin of Species, and in 1866 Mendel in Austria
worked out the mathematical laws of dominance, recessiveness, and
segregation, previously observed but not interpreted by other workers.
Mendel's paper remained unnoticed for many years, but meanwhile
others were hot on the trail of the same conclusions. When his work
was rediscovered in 1900, it gave a tremendous impetus to research
and practical breeding alike. Shortly after this (1902-03), the ob-
served phenomena of heredity were definitely and finally linked with
activities within the cell.
The development of knowledge of the cell goes back at least to the
time of Leeuwenhoek in the Netherlands, who first discovered the
world of the microscope (around 1677). In 1838-39, Schleiden and
Schwann in Germany generalized that all bodies are made up of cells;
l«8904'>— 37 12
170 YEARBOOK, 1937
10 years later Hoffmeister in Germany actually saw chromosomes.
In 1864, Nageli in Switzerland was attributing the control of heredity
to solid particles in the cell — an idea finally clinched by Weismann
in 1892, after Haeckel, Strassburger, Flemming, Von Beneden, and
others had developed more knowledge of the cell nucleus. From this
time on the study of chromosome phenomena proceeded rapidly
through the work of many cytologists, up to our own day when genes
are accepted as the basis of inheritance and more and more of the facts
of heredity are being checked against observed happenings in the
cell nucleus. These developments have contributed also to an under-
standing of animal breeding, which on the practical side goes back
through the work of Bakewell, the Collings, and others of a century
ago, to Mago the Carthaginian, who in pre-Christian times developed
the first known score card for livestock judging. Without mathe-
matics, much of this knowledge would be unusable, and the work of
many mathematicians has contributed to the exact interpretation of
phenomena and to the practical application of theory.
Outstanding among recent developments are the identification of
hundreds of genes in various organisms; the "mapping" of genes
on chromosomes by genetic studies, and cytological proof of the
actuality of these concepts; the use of the pomace fly for extremely
fruitful genetic investigations; an understanding of many complex
gene interactions that modify the original Mendelian laws; an in-
creasing body of knowledge about chromosome behavior, which
promises to open up new possibilities of practical control in breeding;
and the beginnings of knowledge, through the use of X-rays and other
forms of wave energy, of how basic changes in genes and chromosomes
are brought about, so that controlled genetic change becomes a
speculative possibility.
The most recent developments indicate that new researches in
biological chemistry may in their turn throw light on some of the
many unsolved secrets of the gene and its control of heredity.
VEGETABLE CROP BREEDING
AND IMPROVEMENT—
AN INTRODUCTION
VICTOR R. BOSWELL, Principal Horticul-
turist, Division of Fruit and Vegetable Crops
and Diseases, Bureau of Plant Industry
IN CONTRAST with the comparatively small number of different
species of important extensive farm crops — a half dozen cereals, two
fiber crops, two sugar crops, and perhaps a dozen forage crops —
literally scores of common vegetable-crop species are widely grown
over this country. The scientific basis for orderly and efficient breed-
ing of most vegetables is much less highly developed than in the
cereal and sugar crops, for example, and therefore less can be said
concerning the genetics of most individual vegetable-crop species.
Even so, the large number of crops to be considered compels drastic
limitation of subject matter and scope of the articles that follow.
FEW FOREIGN VARIETIES ADOPTED
IN THE UNITED STATES
The excellent and comprehensive treatments of wheat, corn, and
certain other crops in the 1936 Yearbook of Agriculture include much
data upon foreign varieties, breeding, and improvement ; but for many
of our vegetable crops such information either is not available or is
of such limited interest in the United States that its compilation and
publication are hardly practicable. In the main, foreign varieties of
vegetables either do not appeal to our tastes or are not well adapted
to the environment and the methods of handling in the United States.
There are noteworthy exceptions, of course, for there is some inter-
national agreement in consumers' tastes and a few crops show wide
ranges of adaptability. But the activities of foreign workers have
thus far remained to a a large extent of academic interest to us, except
insofar as they dealt with basic problems of genetics or plant culture.
A few examples will explain our limited use of foreign productions.
England stands preeminent in the improvement of the garden pea.
More of our pea varieties (or their parent varieties) originated there
than in all other countries combined. The English climate is quite
cool and moist, ideally adapted to the garden pea, which is sometimes
called the English pea. Even though many of our varieties are
readily traceable to English work, they constitute only a fraction of
the number that have been produced and are still grown in that
country. Most of the English varieties are not at all adapted to
our more extreme and changeable climate. Most of our own varieties
of peas are inferior in quality to the English varieties as these are grown
in England .
Tomatoes are grown in England almost exclusively in greenhouses.
None of our important commercial sorts will bear satisfactorily out
171
172 YEARBOOK, 1937
of doors in England, because the climate is too cool; neither are they
adapted to the English hothouse industry. On the other hand,
English varieties of tomatoes have never become popular in the
United States, because they are too small to suit our growers and
consumers, even for production under glass.
Our growers envy the Italians their ability to produce tomatoes of
such high color and high content of solids and have repeatedly
attempted to adapt Italian varieties to this country, but without
success. Italian tomatoes are not adapted to our climate and soils,
and furthermore, the small size of some of the best makes them
expensive to harvest. Americans demand bigness, not only for
appearance but to facilitate handling and to reduce production costs.
World-wide collections of tomato varieties grown in this country
have revealed none that we can afford to adopt as they are.
The huge Telegraph type of cucumber grown in English greenhouses
has contributed to the development of some of our own varieties, but
Americans will not buy the enormous English sorts. Likewise our
ideas of a good cucumber are unacceptable to the English; our varie-
ties would be considered as nubbins. Again, our varieties for outdoor
culture are of no interest in England, where cucumbers must be grown
under glass.
As .we owe a debt to England for fine peas, so we are indebted to
the Netherlands, Germany, and Denmark for our principal varieties
of cabbage and spinach. The leafy crops reach perfection in those
cool north European countries. Although we adopted their produc-
tions as the best immediately available, they were developed under
environments so different from our own that they are really well
adapted to very few localities in the United States. A Danish seeds-
man who supplies large quantities of cabbage and other seeds for our
growers once said in effect with reference to this fact: "I have never
seen a crop of cabbage in the United States that would be considered
good in Denmark." .
We have adopted a few varieties of vegetables from France, but
only a few — lettuce and celery in particular. Again, French require-
ments and American requirements are so different that one country
rarely seems to be able to make use of the varieties considered good
by the other.
In some countries other than those mentioned there are highly
developed and carefully controlled stocks that are all important to the
respective regions. But in much of the world vegetable breeding and
improvement remains as a quite local enterprise in the hands of
unskilled and untrained workers, or is indeed nonexistent. Imported
or adopted varieties that were once acceptable here, when we had no
others and before growers were beset with so many problems, are now
considered inadequate. Increasing severity of insect and disease
attacks, new techniques of production, handling, and processing, and
ever-changing requirements for market and culinary quality, all com-
bine to make new variety problems and to make them rather pecu-
liarly our own.
In general, vegetable-crop species do not have the world-wide
importance possessed by the cereals, sugar plants, fiber plants, and
tobacco. Tomatoes, peppers, sweet corn, squash, and pumpkin are
VEGETABLE BREEDING 173
all believed to be of New World origin and do not have tbe long cul-
tural history of certain staple crops ; they are comparatively unknown
in large parts of the Far East. Until a scant hundred years ago the
tomato was thought to be deadly poisonous even in America, and
most Europeans still think corn is unfit for human consumption. In
our turn we are entirely unacquainted with scores of Asiatic vege-
tables, some of which might well be consumed in this country.
This "local" or national interest in varieties and species does not
mean that we minimize the value of foreign sorts as possible parents
in breeding and improvement work in the United States. Some of
the most significant improvements ever effected have been through
using certain commercially worthless and practically inedible forms
for hybridizing with commercially desirable varieties to obtain new
disease-resistant sorts.
PRIVATE AND PUBLIC IMPROVEMENT AGENCIES
In an appraisal of vegetable-variety improvement up to about 1925,
primary recognition must be given to private growers, seedsmen, and
amateurs. It is only in the last 10 or 15 years that research institu-
tions in this country or abroad have been much of a factor in the
breeding and selection of new and improved varieties of vegetables.
Prior to that time most of the advancements in yield, appearance,
and quality had been brought about by private workers, mainly
through mass selection. Some very productive hybridizing was pur-
posefully done, and approximate pure-line selection methods were
applied to closely self-fertilized crops like peas and beans.
In recent catalogs of two of the larger and more progressive seed
firms, approximately 675 and 500 vegetable varieties are listed,
respectively. Of these numbers, approximately 6.5 and 5.5 percent,
respectively, represent varieties originated and introduced to the
trade by State and Federal research agencies, the remainder being
the results of private enterprise. It must not be concluded, however,
that these percentages represent the proportions of total acreage and
production of varieties bred by State and Federal workers. In
certain areas and for certain crops a very large share of the total
consists of new disease-resistant varieties. Furthermore, hundreds
of varieties listed are of quite minor value. Ten years ago probably
not over 1 or 2 percent of the varieties listed were the result of work
by public investigators; and it is predicted that 10 years hence the
proportion will have increased much more.
Until the last few years private growers and seedsmen were able to
effect improvements of such character and at such a rate that the
requirements of the industry were reasonably met. With increased
knowledge of breeding technique as demonstrated by research workers,
the seedsmen can do and are doing better work than in the past ; but
the increasing complexity and magnitude of numerous problems are
demanding that public agencies provide solutions to them. With
public agencies searching out genes for superior characteristics and
introducing them into new varieties, private interests will extend the
distribution of those genes into many more varieties and strains.
It should not be supposed that two catalog lists of new varieties
bred, named, and introduced by public agencies represent their entire
174 YEARBOOK, 1937
contribution to vegetable improvement. As has been pointed out for
other kinds of crops, they have devised shorter and more effective
methods of improvement that are gradually coming into general use
by commercial agencies. The Federal and State workers have also
accomplished incalculable benefits by the simple procedure of develop-
ing superior stocks of old varieties by selection, freeing stocks of
mixture and disease, and releasing the resulting material into trade
channels. Some of the best and latest productions will not be gen-
erally offered for sale for another year or so.
NEW INFLUENCES IN VEGETABLE IMPROVEMENT
Although the avoidance of contamination with disease is perhaps the
foremost consideration in seed certification by several States, certi-
fication also relates to trueness to varietal type and freedom from
rogues and mixtures. This certification does not involve original
breeding or improvement but does compel the application of up-to-date
methods of maintaining advances that have been made by breeders.
Certification, therefore, deserves mention as a public service closely
allied with improvement. From a practical standpoint it has resulted
in very substantially raising the standards of performances of tens of
thousands of acres of vegetable crops.
Under authority of the Bankhead-Jones Act, passed in 1935, the
Division of Fruit and Vegetable Crops and Diseases is developing near
Charleston, S. C, a well-equipped vegetable breeding laboratory for
the study of fundamental breeding problems that are basic to the pro-
duction of new and improved varieties for the South and Southeast.
Solutions to these problems of national and world interest will of
course be forthcoming. Rapid progress is being made in providing
facilities for research, and a small but able and active staff has been
at work since the spring of 1936. The establishment of this station,
the only one in this country devoted exclusively to vegetable breed-
ing, is a particularly significant step, but is only one of the signs of the
times. The study and application of genetics are certain to solve an
increasing number of our problems and contribute greatly to the
general welfare.
Another station in the United States that may well be expected to
make unusual contributions is the Great Plains Horticultural Field
Station, of the Division of Fruit and Vegetable Crops and Diseases, at
Cheyenne, Wyo. A most extensive collection of thousands of domes-
tic and foreign varieties, strains, and stocks of vegetables has been
acquired by that station in the quest for characteristics of earliness,
drought resistance, and cold resistance. Vast stretches of our western
United States have such a short growing season by reason of high lati-
tude or altitude, and such extremes of temperature, with low humidity,
drying winds, and short water supply, that only a very meager list of
vegetable varieties can be grown. There is pressing need for either
introducing or breeding varieties of nearly all crops for home and local
market use by people living in those areas. The staff of the station
at Cheyenne includes men highly trained in horticulture, genetics,
cytology, and physiology. The joint efforts of all are directed to the
examination of promising material and the execution of a breeding
program designed to meet the.requirements of the region.
VEGETABLE BREEDING 175
The Division of Plant Exploration and Introduction of the Bureau
of Plant Industry plays an. important part in the breeding programs,
not only of Federal agencies but of all the State experiment stations
that call upon that Division for help. Their information upon the
geography of plants, their constant close contacts with investigators
and dealers all over the world, their exploring expeditions into obscure
places, combine to make available to plant breeders in this country a
wealth of the world's plant materials that is remarkable. And natur-
ally the Division assists foreign investigators by supplying in exchange
considerable quantities of material from American collections. The
world's supply of plant materials is becoming diffused into all coun-
tries for anyone to use who will.
PRESENTATION OF SUBJECT MATTER
A few words are in order with reference to the organization of subject
matter in the articles on vegetable breeding. It is obviously imprac-
ticable to treat each crop extensively, therefore crops have been
grouped for treatment. Groups are based on botanical and struc-
tural similarities in most cases, but a few on the basis of similarity of
use or purpose for which they are grown. This grouping has been
adopted purely as a matter of convenience in compiling the informa-
tion or for presenting together crops of related interest regardless of
botanical relations. It is not to be considered as a scientific classifi-
cation. In most cases the authors of the respective articles are now
conducting breeding or genetic investigations or have had special
breeding experience with the crops under discussion.
It will be noted that the appendix to this group of articles (p. 340)
contains data on a number of unclassified crops not discussed in detail
in the articles, such as peanuts, sweetpotatoes, and others. Definite
information on the breeding, improvement, and genetics of these crops
is indeed meager despite the great economic importance of some of
them. There is practically no exact knowledge about inheritance in
the sweetpotato, and even the origin of surprisingly few sorts is known.
The peanut until quite recently has been almost ignored by scientific
breeders and students of genetics, but it is due for increasing attention.
IMPROVEMENT AND
GENETICS OF TOMATOES,
PEPPERS, AND EGGPLANT
VICTOR R. BOSWELL, Principal Horticul-
turist, Division of Fruit and Vegetable Crops
and Diseases, Bureau of Plant Industry
I
TOMATO
NSOFAR as we are able to tell from written record, the tomato is
a very new crop (18).1 The oldest records of it date back less than
400 years, a brief time when compared with the oldest available records
of many other crops. The tomato is of tropical American origin, and
early reports indicate that it was planted in maize fields and eaten
by the ancient Mexicans, who called it tomati. Apparently it attained
no very important place in the lives of those people, perhaps on
account of the highly perishable nature of the edible fruit and the
absence of known means for its preservation. Although it is believed
to be native to the same regions as certain early forms of maize, there
are no known prehistoric remains, no prehistoric sculpture or ceramics
to record its early culture as in the case of maize, kidney beans, lima
beans, and squash in North America, or wheat and numerous other
plants in' the East. We thus are able to form no definite idea of its
antiquity and early importance. The absence of record or remains of
plant parts might imply relative unimportance and little use. On the
other hand, the earliest references in the literature describe essentially
the same forms that are grown today. No new markedly different
fruit types are known to have appeared since, and the large forms have
never been found truly wild. It is therefore believed that the tomato
was already improved far beyond the wild state when North America
was discovered. Even so, our smooth, large, symmetrical-fruited
varieties of today are in marked contrast to the rough, variable types
known in this country a century ago.
We have all heard how the able, up-and-coming young man is
rarely appreciated in his native environment but must go abroad to
make good, and then returns to receive the approval of his country-
men. Some of our native American crops, including the tomato,
have gone through a similar experience. The potato, native to the
New World, is called "Irish potato" because colonial America repatri-
ated it to the New World from Ireland, where it had become a very
important crop while it was being ignored close to its native land.
The tomato was introduced into Europe early in the sixteenth century
and became widely distributed. In the seventeenth century it Avas
grown in England for ornament only, although it was known to be
eaten elsewhere. By the end of the eighteenth century it was grown
i Italic numbers in parentheses refer to Literature Cited, p. 204.
176
TOMATOES, PEPPERS, AND EGGPLANT 177
on a field scale in Italy and used extensively as food, but it was a half
century more before people in the United States generally dared to
Early Varietal Adaptation
Although each of several countries in which tomatoes are grown to
any large extent usually has a number of varieties that show a con-
siderable range in varietal characteristics among themselves, the
group of varieties grown in each region is rather distinct from those
grown in certain other parts of the world. Not every country has
its own distinct general type, but there are marked differences between
geographic areas. It is probable that definite selection and breeding
work with the tomato for adapting it to warm-temperate and cool-
temperate regions has been in progress but a short time, not over two
centuries and perhaps only half that. Nevertheless, in a certainly
brief span this tropical or subtropical plant has been adapted to a
wide range of environments far different from its native home. The
efforts at selection by early growers of the crop together with natural
factors produced a very interesting and effective assortment of general
types, each of which apparently points toward the maximum adapt-
ability in each region.
The best Italian varieties in general are of long season and are
large, vigorous growers, with a profusion of thick-walled fruits of
unusually brilliant color and high content of solids. A wide range in
fruit size exists among these varieties, some of the most valuable
being small, as judged by United States preferences. The important
point is that those varieties do better in Italy than elsewhere and are
better for Italian purposes than others that have been tried in Italy.
There is a considerable outdoor culture of tomatoes in Germany
and some adjacent north-European areas. The varieties grown
there are early, relatively small-vined, and medium- to small-fruited.
THE early tomato breeders did excellent work in producing plants
with good yields of large handsome fruits, adapted to local or regional
conditions; hut the situation has changed, and new problems and
requirements have arisen so fast that it is not now possible to keep
ahead of them by the old method of selecting chance valiants in the field.
Systematic effort is necessary to find and bring together character-
istics that will make entirely new varieties resistant to specific dis-
eases and to heat and cold, and adaptable to long-distance shipment,
to new areas of culture, to new processes or means of utilization.
This is the kind of work being done by State and Federal agencies-
The disease problem especially is so important today that practically
no research agency would introduce any new variety unless it were
resistant to at least one very troublesome disease.
178 YEARBOOK, 1937
Italian and most United States varieties are not adapted to the cli-
mate of Germany, and the German varieties when grown in the
United States are distinctly inferior to our own. Except for color
differences, the north-European sorts are largely of the one general
type described.
As mentioned in the introductory article on vegetables, the English
have developed a characteristic type of greenhouse tomato, some
varieties of which are practically parthenocarpic, requiring no polli-
nation, by hand or otherwise, as American varieties do, in order to
set fruit. These varieties are very prolific, setting very large num-
bers of fruits that are too small to suit American growers and con-
sumers— but they are well adapted to the region and to the purpose
for which they are grown. They were the first improved varieties
in the modern sense.
In a large country like the United States, with a climatic range from
subtropical to cool temperate and from humid to arid, different variety
groups have been developed to suit different parts of the country.
Until about 10 years ago most of this adaptation had been effected
by private growers and seedsmen, who selected chance variants or the
progeny of natural crosses that were particularly promising in a given
region. A few of the old important varieties were the results of
artificial hybridizing. Extensive commercial tomato production in
this country is not much over 50 years old. Sixty years ago the only
large sorts were rough, ugly, heavily ribbed, variable "varieties" of
indifferent quality, although some good small ones of the greenhouse
type had been brought in from England.
The old varieties were certainly quite heterozygous or mixed in
their hereditary composition, for the tomato frequently crosses
naturally in the field. Bailey (3) and others have referred to tomato
varieties running out. These cases were doubtless due to the effects
of. more or less accidental selection within very mixed populations.
These few rough and ready mixtures, our early so-called varieties,
were the confused mass of raw material from which so many of our
really good varieties have been selected, directly or indirectly, by
keen-eyed growers. Tomatoes are now grown commercially in every
State in this country.
Improvement in the United States, 1850-1910 2
Prior to 1860 no tomato varieties had been developed in the United
States. The few varieties known had been brought in chiefly from
England and a few from France. It appears that most of the large-
fruited varieties, if not all of them, had been obtained by selection
from the old Large Red or ribbed type that had been known since
about 1550. The smaller fruited, more prolific forcing or greenhouse
types and similar sorts presumably were first selected from the round
tomato (smooth), which was originally described by Tournefort about
1700. Since there has been only a minor interest in the small-fruited
forms in this country, a chronology of tomato improvement will be
confined largely to the story of the old Large Red and its descen-
■ln the preparation of this historical review the writer has freely used unpublished notes and records in
the files of the Division of Fruit and Vegetable Crops and Diseases made by the late W. W. Tracy, Sr., and
by D . N . Shoemaker and other former staff members.
TOMATOES, PEPPERS, AND EGGPLANT
179
dants. The old Round, however, has apparently contributed some
genes of value. The cherry-, pear-, and plum-shaped tomatoes have
been known as long as the Large Red but have undergone no appreci-
able change.
Probably the first true dwarf or "tree" variety, named Tree, was
introduced by Vilmorin-Andrieux & Cie., of Paris, in I860, and was
promptly brought into this country. It was found as a chance variant
in a tall variety by a private gardener of an estate at Chateau de Laye
in France. Two other imported varieties of interest in the United
States, introduced about that time, were Fiji Island (1862) and Cook
Favorite (1864). Several forcing types of European origin were being
grown, but their origin is obscure.
Probably the first United States contribution to tomato improve-
ment was the introduction of the Tilden variety by Henry Tilden, of
Davenport, Iowa, in 1865. It
originated as a chance seedling in
a field of a variety the name of
which is not recorded (3).
The next notable advance oc-
curred in 1870 with the introduc-
tion of Trophy, a result of hy-
bridization and selection by a
Dr. Hand, of Baltimore County,
Md. It is said to have been from
a cross of Large- Red X Early
Red Smooth. The variety was
introduced by G. E. Waring, of
Newport, R. I., who received it
as a supposedly fairly well-fixed
stock from T. J. Hand, the son
of the originator. It has been
stated that Trophy was involved
in the parentage of most of the
varieties introduced in the follow-
ing quarter century, and un-
doubtedly it has contributed, at
least indirectly, to a great number
of later varieties. The old origi-
nal Trophy was evidently not
very well fixed, however, for
before 1900 it had practically ceased to exist (3). Through both pur-
poseful and accidental hybridization, and through artificial selection
and natural selection within a rather heterozygous variety, superior
variants were saved and inferior ones discarded. There is evidence,
too, that the perpetuation and increase of undesirable variants appear-
ing in the variety (running out) as a result of segregation, natural
crossing, mechanical mixture, or combinations of these, hastened the
demise of the variety.
The work of A. W. Livingston (fig. 1), of Columbus, Ohio, and his
associates and successors in the Livingston Seed Co. has resulted in the
introduction of more new varieties than that of any other private group.
Most of the varieties introduced by the Livingstons were of their own
Figure /.— A. W. Livingston (1822-98),
pioneer tomato breeder of Columbus, Obio,
who developed many tomato varieties still
in current use.
180 YEARBOOK, 1937
finding or origination, but some were obtained from other growers.
Paragon, from a chance seedling, was their first introduction (1870).
The famous old variety Acme was developed by A. W. Livingston
from a single superior plant found in a field of mixed stock and intro-
duced in 1875. Like the Trophy, this variety was the source or served
as one parent of many subsequently introduced varieties. In 1880
Perfection, a chance variant in Acme, was introduced. Livingston
next brought out Golden Queen in 1882, Favorite in 1883, Beauty in
1886, Potato Leaf in 1887, Stone (4) in 1889, and Royal Red in 1892.
This last was developed from seven similar plants found in a field of
Dwarf Champion by M. M. Miesse. The others just named were
chance seedlings occurring in varieties the names of which are not
known. These were followed by Aristocrat and Buckeye State in
1893, Honor Bright in 1897, and Magnus in 1900, as chance seedlings
in varieties not recorded. In 1903 Dwarf Stone was introduced;
it was a chance seedling found in Stone. Globe (4) is from a cross
between Stone and Ponderosa made about 1899 by Robert Livingston
and was introduced in 1905. Hummer, another introduction, was
selected out of Paragon.
Of this impressive list introduced by the Livingstons, Stone and
Globe are among the most important varieties grown today. Acme,
Beauty, Buckeye State, Dwarf Stone, Golden Queen, and Perfection
are still listed by some seed producers although they are not exten-
sively grown.
In 1882 D. M. Ferry & Co. obtained a selection made by a farmer
grower from an unknown variety, and they introduced it in 1885 as
Optimus.
Some introductions of W. Atlee Burpee & Co. were Matchless,
introduced in 1889; Fordhook Fancy, a production by E. C. Green,
of the Ohio Agricultural Experiment Station, in 1898; Combination
(Lorillard X Acme X Comet) in 1896; and Quarter Century in 1899 —
a cross between Lorillard and Dwarf Champion. These last two were
developed by Walter Van Fleet, then of the Rural New Yorker.
In 1887, at the Michigan Agricultural College, L. H. Bailey "selected
a single outstanding plant from a plot of a German variety, Eiformig
Dauer. This was released as the Ignotum variety and proved to be of
major importance for many years.
Several varieties that had attained importance prior to 1910 are
either of obscure parentage or their parentage has been reported and
the introducer's name is not definitely known. Lorillard, named for
its producer, was introduced in 1888 and was said to be from a cross
between Acme and Perfection. The following are of unknown
parentage: Chalk Early Jewel, by Moore & Simon in 1900 ; Ponderosa,
by Peter Henderson in 1891; Early Detroit (4), from seed obtained
from a Mr. Rosendahl, of Fort Leavenworth, Kans., introduced in
1909 by D. M. Ferry & Co.
The Stone variety has been the supposed parent stock of several
varieties of considerable importance, among them Dwarf Stone, men-
tioned above; Earliana (4), found by George Sparks, of Salem, N. J.,
and introduced in 1900 by Johnson & Stokes; Greater Baltimore (4),
found by John Baer, of Baltimore, Md., and introduced by J. Bolgiano
& Sons in 1905.
TOMATOES, PEPPERS, AND EGGPLANT 181
Johnson & Stokes introduced Bonny Best (4) in 1908. It came
from a single plant selection in a field of Chalk Early Jewel by G. W.
Middleton, of Jeffersonville, Pa.
With all duo credit to the important contributions of other growers
seedsmen, and investigators, it is not out of place to call attention
again to the great contribution of the Livingston Seed Co. to tomato
improvement. Of about 40 varieties that had attained a distinct
status prior to 1910, a third were productions of or introductions by
the Livingston company. If we add those varieties derived directly
from Livingston productions and introductions, it appears that half
of the major varieties were due to the abilities of the Livingstons to
evaluate and perpetuate superior material in the tomato.
Private Introductions, 1910-36
Due credit must be given the early workers mentioned in the pre-
ceding pages. Their object was to get good yields of large handsome
fruits borne by plants adapted to local or regional conditions, and they
succeeded admirably — so well, in fact, that about half of the 40
important varieties known in 1903 are still listed by at least a few of
the larger producers and dealers. A few varieties, ' notably Chalk
Early Jewel, Earliana, Ponderosa, Stone, and the dwarf sorts are
universally listed. This older type of effort still continues, and from
time to time some quite worth-while strains result from it. In com-
parison with the period 1875 to 1900, however, the old method of
selection and crossing among present commercial sorts has in recent
years resulted in a smaller number of marked improvements. Many
of those obtained have been of value, particularly with respect to
regional adaptation and suitability for long-distance shipping or for
manufacture.
The Cooper Special, a variety with a distinctive, determinate, or
"self- topping" habit of vine growth, was introduced by C. D. Cooper,
a farmer near Fort Lauderdale, Fla. It was found as a chance
seedling by Bert Croft in Florida in 1914.
Grand Rapids Forcing, long a popular greenhouse variety, was pro-
duced by John Nellist, a grower near Grand Rapids, Mich., by crossing
Bonny Best and Comet, an English variety.
In 1915 John Baer, of Baltimore County, Md., turned over a selec-
tion from Bonny Best, which was named John Baer, to J. Bolgiano &
Sons for introduction. Although similar to Bonny Best in many
respects, this strain or variety seems particularly adapted to the north-
eastern group of tomato-growing States and is often preferred to other
stocks offered under the name of Bonny Best.
In 1920 the Everett B. Clark Seed Co. introduced an early shipping
variety, named Clark Early, for culture mainly in the South. It was
obtained by selection. D. M. Ferry & Co. in 1921 introduced Gulf
State Market, a variety very similar to Globe but a trifle earlier in
the South and less susceptible to cracking. It was found as a single
plant in a field of Early Detroit by Walter Richards, of Crystal
Springs, Miss., in 1917.
The J. T. D. is an interesting example of a local type developed for
adaptation to a specific set of conditions and needs. It was developed
182 YEARBOOK, 1937
by the Campbell Soup Co. for growing in New Jersey, mainly for its
own factory use. It has not become widely grown elsewhere.
In addition to these rather distinct sorts, several commercial firms
and seed growers have given special attention to the isolation of
superior stocks and strains of a number of the leading commercial
varieties. Some of these stocks have been introduced under new
names but frequently with only slight variation in the accepted
name. A new name or a modified name does not, of course, insure
improvement or even a difference. It may fairly be stated, however,
that a number of these carefully handled "special" commercial strains
of well-established varieties have proved to be superior to stocks
generally available under the common name.
Improvement by Public Agencies
A discussion of the research that makes possible more rapid and
orderly improvement of the tomato will be found in the section on
Studies of Inheritance and Cytology at the end of this article. At
this point will be presented a historical review of the new varieties
introduced by State agricultural experiment stations and the United
States Department of Agriculture.
In the last 25 years new problems and requirements have arisen so
fast that tomato breeders cannot find naturally occurring chance
variants with the desired characteristics fast enough to keep ahead of
requirements. Special efforts are necessary to find and bring together
these newly required features to produce new combinations, entirely
new and different varieties. Of course the old objectives of large,
smooth, high-quality fruit and high yields are still sought, but they
must be in combination with such factors as tolerance or resistance to
specific diseases, to heat, to cold, and adaptability to long-distance
shipment, to new areas of culture, and to new processes or means of
utilization. These characteristics are difficult to find and combine
quickly with other desired properties.
Introductions prior to 1910 by public agencies were few and far
between. Reference has already been made to Ignotum, selected by
Bailey at the Michigan Agricultural College, and Fordhook Fancy,
produced by Green at the Ohio station.
The major part of the tomato breeding by State and Federal agencies
has been done in efforts to develop varieties resistant to disease.
Thus far most attention has been devoted to resistance to fusarium
wilt (fig. 2), but resistance to other diseases has also been sought,
namely, nailhead rust, leaf spot, leaf mold, mosaic, and curly top.
The disease problem in general has become so important that today
there is little inclination on the part of research agencies to introduce
any new tomato variety unless it is resistant to at least one very
troublesome disease.
Selection for resistance to fusarium wilt was first started in 1910 by
Essary (Id), of the Tennessee Agricultural Experiment Station, and by
Edgerton (18), of the Louisiana station. Two years later Essary dis-
tributed a resistant strain of the general type of Beauty but with a
scarlet fruit like the color of Stone. This new sort, developed by mass
selection from a diseased field near Gibson, Tenn., became known as
TOMATOES, PEPPERS, AND EGGPLANT
183
Tennessee Red. Later Essary distributed a wilt-resistant variety with
scarlet-red fruit, named Tennessee Pink, also developed by mass se-
lection in seriously diseased fields. Edgerton, in Louisiana, announced
his first wilt-resistant sort in 1912. It was called Louisiana Wilt Re-
sistant and was developed from a single resistant plant selected in a
badly infected field of Acme.
Although Louisiana Wilt Resistant proved highly resistant to the
disease, it was late and a poor yielder. Edgerton crossed it in 1912
with the Langdon strain of Earliana to get earliness and fruitfulness.
From the progeny of this hybrid a scarlet and a scarlet-red strain —
~*!ps
V
^^^^^H
- •■
X*'' r"*-
,
JyBSfqBDB
^r*K' /*l\Tg»-'
!&&
■ ~< - v - y
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gifcVg
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Figure 2. — A comparison of wilt-susceptible (A) and will-resistant (B) varieties of
tomatoes on heavily infected land.
commonly called "red" and "pink", respectively — were isolated, named
Louisiana Red and Louisiana Pink, and distributed about 1918.
Norton {40), of the Maryland station, began selection for wilt re-
sistance in 1912, selecting from a large number of varieties grown neat-
Preston, Md., on a field naturally heavily infected. A number of un-
named resistant selections were distributed in 1915 to tomato growers
and investigators. One of these, a wilt-resistant strain of Greater
Baltimore, was further selected and grown for seed for several years
by O. W. Twilley, of Hurlock, Md. In 1912 Norton selected a wilt-
resistant sort from a field of badly damaged mixed varieties near
Vienna, Md. This was included among strains given in 1915 to F. J.
Pritchard (fig. 3), of the Department of Agriculture, who started his
disease-resistant improvement work in that year. Two years of fur-
184
YEARBOOK, 1937
ther selection in this strain by Pritchard resulted in the Norton variety,
distributed in 1917 by the Department and named for the man who
made the original resistant plant selection. Two other resistant
strains that Norton gave to Pritchard in 1915 were selected by the
former from fields of Greater Baltimore. Pritchard selected them
further under conditions of heavily artificially infected soil and dis-
tributed them in 1918 under the names of Columbia and Arlington.
These three varieties, Norton, Columbia, and Arlington (42), de-
veloped by the informal joint efforts of the Maryland Agricultural
Experiment Station and Department workers, were widely dissemi-
nated and were the leading resistant varieties, particularly in the
East, for some years.
Pritchard distributed a third improvement in 1918 under the name
of Marvel. He obtained it by selection from a French variety,
Merveille des Marches (Marvel of
the Market) , which sh ows a rather
high and fairly uniform resistance
(42).
Since 1917 the wilt-resistant
varieties produced by the De-
partment have greatly predomi-
nated over those originated by
others. For reasons not entirely
clear, those produced by various
State experiment stations have
remained more or less localized,
and the total acreages of them are
not very great. It may be that
in the course of production and
testing the limited opportunities
of determining wide adaptability
resulted in selections that were
especially adapted to a rather
narrow range of conditions; or it
may be that the larger resources
of the Department made possible
not only more extensive tests but
larger supplies of seed for original
distribution and more effective
dissemination of information
about the new sorts. It seems
probable that some of the State work has resulted in varieties quite the
equal of the Department sorts now commonly grown, or even superior
to them in some respects, but still the latter dominate the field.
It should be recognized here that some of the first stocks of certain
Department varieties distributed were the result of massing a number
of selections that were apparently similar under the conditions of
selecting. Under other growth conditions, undesirable variations in
fruit and plant form appeared. Numerous State and private agencies
have contributed to the success of these varieties by careful rogviing
or selection within the early stocks, keeping them in closer conformity
to the ideals for the respective sorts.
Figure 3. — F. J. Prilchard, of the United
Stales Department of Agriculture, who did
notable work inbreeding improved disease-
resistant varieties of tomatoes.
TOMATOES, PEPPERS, AND EGGPLANT 185
In 1922 Pritchard introduced Norduke, a cross (Norton X Duke of
York) between two resistant sorts. Marvana (Marvel X Earliana)
and Marvelosa (Marvel X Ponderosa) followed in 1924. All these
earlier introductions by the Department are still listed by commercial
firms (most firms list only one or a few of them), but they are unim-
portant and are not generally grown except in certain localities.
Subsequent superior productions have largely displaced them.
The Marglobe (4), introduced by Pritchard and Porte in 1925, is
without doubt the most important variety of tomato in the United
States and in the world today. Its range of adaptability to both en-
vironmental and utilitarian requirements and its dominant position
have been surprising. Marglobe is the result of a cross between Globe
and Marvel made in a greenhouse of the Department in Washington in
1918. Globe has considerable resistance to wilt but is very susceptible
to nailhead rust. Marvel is highly resistant to both. Marglobe
proved highly resistant to wilt under most conditions and to nailhead
under all conditions of which there is record. It was introduced just in
time to save the Florida tomato-shipping industry from virtual ex-
tinction through the ravages of nailhead and wilt. It was developed
primarily as a shipping tomato, but it has turned out to be the princi-
pal canning variety in the Middle Atlantic and South Atlantic States,
as well as the leading shipping variety of the whole Atlantic region.
It was the dominant variety in Mexico during the heyday of the
tomato-shipping industry in that country ; it is one of the best varieties
recommended in Australia, and it is currently listed by commercial
vegetable seedsmen in many foreign countries. The Marglobe has
been to the present generation what Trophy and Acme were two
generations ago. But ultimately, perhaps before long, it will be
superseded by still better sorts, for, like all varieties, it has its limita-
tions. It cracks rather badly, particularly in the Middle West, and it
is not appreciably resistant to a number of diseases that are becoming
increasingly important.
Three more recent productions by Pritchard and Porte should be
mentioned before returning to some of the earlier work of the State
stations. Marglobe was a parent in two of these — Break o' Day
(Marglobe X Marvana), introduced in 1931, and Pritchard8 (Cooper
Special X Marglobe), introduced in 1932. Break o' Day was re-
ceived much more enthusiastically than Pritchard, as a result of
preliminary trials; but it has subsequently slipped into a relatively
unimportant place, largely because it fails to meet rigid color require-
ments under most conditions. Pritchard, however, has become very
popular on account of its superior scarlet color, despite the fact that
it tends to bear most of its crop in a short time. It was expected to be
of no value to canners because of this habit, but it is being used more
each year. The third variety, Glovel 4 (Globe X Marvel), is a "sis-
ter" to Marglobe but is scarlet-red ("pink") instead of scarlet ("red").
It is otherwise rather similar to Marglobe and is especially interesting
because it cracks much less than Marglobe. Although reports on it
> Introduced under the name of Scarlet Topper. Renamed Pritchard in 1932 after Pritchard's death in
January 1931.
* Produced in cooperation with the Florida Agricultural Experiment Station.
138904°— 37 13+ +
186 YEARBOOK, 1937
are generally good, it is too early to determine its value, since it was
introduced in the spring of 1935 and first grown commercially in 1936.
These last three varieties are all resistant to both fusarium wilt and
nailhead.
The most important variety in the middle-western canning area
of Illinois and Indiana is the Indiana Baltimore, developed by the
Indiana Agricultural Experiment Station by selection from Greater
Baltimore and distributed in 1919. It represents a distinct improve-
ment over its parent variety, although the casual observer would
consider it similar.
Yeager (54) , of North Dakota, has done some of the most interest-
ing tomato breeding in this country, but his work is not generally
known and appreciated outside the northern Great Plains area.
Yeager has bent his efforts to the development of a list of varieties
adapted to a short, rather dry season in- a region of wide extremes
of temperature and frequent desiccating winds. These conditions
are decidedly unfavorable for tomatoes in general. It is only in the
last 12 years that farmers and gardeners of the northern Great
Plains have had varieties that could be grown there with any sat-
isfaction, but now they have several. Even though these varieties
from the North Dakota station are adapted to the area in question
and are far better there than anything heretofore available, they are
of little interest elsewhere. The very characters that enable them
to succeed in North Dakota appear valueless, for example, in
Virginia. That, however, is no discredit to the varieties or the
introducer. They serve the purpose for which they were bred, and
that is enough.
The seven varieties introduced by Yeager up to this time are all
early and bear their moderate crops on comparatively small plants
in a short time. This is necessary in order to meet the requirements
of the region. All were developed by hybridization, one of them
involving an interspecies cross. Red River (Earliana X Sunrise), in-
troduced in 1925, and Bison (Red River X Cooper Special), introduced
in 1929, are the best known and most important thus far. The latter
has shown an appreciable resistance to heat. Two yellow varieties,
Fargo Yellow Pear (Bison X Yellow Pear) and Golden Bison (Bison X
Golden Queen), introduced in 1932, meet the requirements of those
gardeners who desire yellow-fruited sorts. Farthest North is of
particular interest because of its parentage (Bison X Red Currant) and
its extreme earliness. It was introduced in 1934, so it may be rather
too new to tell how important it is going to be. The other two of
Yeager's introductions are Early Jumbo (June Pink X Globe), dis-
tributed in 1929, and Pink Heart (Bison X Ohio Red), distributed in
1932.
The Santa Clara (4) tomato, which is now the principal variety
grown for canning in California, is the result of work by several agen-
cies and men. It traces back to a single plant selection made in 1923
by a representative of the Canners League, in a field of a variety called
Trophy or Canner. This was not the old original Trophy previously
mentioned, nor even the variety generally cataloged under that name
by seedsmen. It was a large, irregular, rough-fruited sort that was
wasteful and difficult to prepare for canning on account of corrugations
TOMATOES, PEPPERS, AND EGGPLANT 187
and catfaces, and was grown only for canning in that section. The
Canners League, the Ferry-Morse Seed Co., the California Packing
Corporation, and the California Agricultural Experiment Station all
contributed to the further selection and final development of this
huge, moderately smooth-fruited variety that entered into commercial
production about 1926. It has a very large heavy-yielding plant
that produces the largest fruits of any of the extensively grown com-
mercial sorts, but anyone who tries to grow it east of the Rocky
Mountains will bo disappointed in it. It is excellent in parts of
California but almost a failure in other parts of the country.
In 1928 the California station released a selection from Santa Clara
developed through careful inbreeding and called California 55. It
was produced for its smoother fruits, high yield, and more intense
red color.
The Illinois, Massachusetts, and Michigan stations have placed
emphasis on greenhouse sorts because of the magnitude of the forcing
industry in their States. In 1930 Illinois introduced Lloyd Forcing
and Blair Forcing, both derived from Louisiana Pink X Grand Rapids.
Both varieties are wilt resistant. In 1931 Massachusetts introduced
Waltham Forcing, a selection from an unknown sort for adaptation
to adverse northern greenhouse conditions.
The New Jersey station distributed the Rutgers variety in 1934.
It is a cross of Marglobe X J. T. D. and has been reported especially
valuable on the light sandy soils of New Jersey. The Illinois station
has just released sorts that will set fruit and not grow out of bounds
on the high-nitrogen praire soils of Illinois. The Washington (State)
station introduced in 1930 Seedling 36 and Seedling 50, results of
crossing Bonny Best X Best of All to obtain higher productivity under
Washington conditions. They were intended to be adapted to a
specific environment, hence it is not surprising that they have remained
of rather local interest.
Within the last year or two many stations have released several
additional strains and varieties that may or may not make important
places for themselves. Small plot tests, even though numerous and
fairly widespread, often fail — in fact usually fail — to reveal the true
commercial possibilities of a new line and to indicate the reactions of
the tomato-growing industry and the consuming public. Only time
and general commercial trial can determine these tilings. The newer
introductions, as reported by their originators, are listed in table 4
of the appendix to the vegetable articles, along with those discussed
in this brief survey.
Gratifying progress has been made in the selection of verticillium
and fusarium wilt resistant strains of tomato in California by Michael
Shapovalov, of the Department, and B. A. Rudolph, of the California
station, working cooperatively.
PEPPERS
History
The hot and the sweet peppers grown in the United States belong to
a quite different group of plants from the black or white pepper of
commerce. The peppers that we grow in this country are Capsicum
188 YEARBOOK, 1937
annuum L., a New World species native to the Tropics. There are
no ancient eastern names for the species, and the first record of it
(1493) indicates that Columbus took the first specimens to Europe
on returning from his first voyage to the West Indies. Peppers or
chilis are known to have been one of the principal foods of the native
inhabitants of tropical America. The pepper had already reached
a fairly modern state of improvement at the time of its discovery by
Europeans, as evidenced by the wide diversity of the several distinct
sorts described in the early records. All the types current today were
known to be used by the natives of Central America in the seventeenth
century (18). It would thus seem that the prehistory of the pepper
might closely parallel that of the tomato.
There seems to have been no such aversion in Europe and colonial
America to the use of peppers as there was to tomatoes. Peppers
were apparently adopted immediately, and their use quickly became
almost worldwide. Certain types became established so promptly in
India, for example, that some of the early botanists believed them
native to the East. However, the name "chili", which is still used in
India, strongly indicates importation from South America.
Although they were quickly adopted and have been generally used
beyond their native land for over 400 years, the properties of most
varieties of peppers do not make them a product to be eaten in large
quantities as a staple vegetable by most users. Generally peppers,
even the sweet or nonpungent varieties, form a small proportion
of salads or mixed vegetable dishes. Some nationalities, however,
use them more or less "straight", the Mexicans in particular con-
suming almost incredible quantities of them. And those who are
familiar with Mexican cookery know how generously the fiery varieties
are used.
Improvement in the United States
Since the pepper is not a major crop, it has received far less attention
than its relation the tomato. Even though a few enthusiasts have
effected some excellent improvements, the importance of the crop
itself has not been great enough to attract much attention to more
than a few of the advances made. As a result, the records concerning
early improvement are very sketchy and incomplete. Unfortunately,
no such dependable varietal history can be written for this crop as
for the tomato.
In 1901 American seedsmen listed between 125 and 150 varietal
names of peppers in their catalogs. Of this number only 18 to 20
probably denoted really distinct varieties, the others being merely
synonyms or cases of misnaming. The history of those varieties,
with few exceptions, is indeed obscure. It is noteworthy, however,
that after 35 years these distinct sorts are all still available commer-
cially with one or two possible exceptions. Furthermore, there have
been few very distinct or very marked improvements in type. Many
new names have appeared for old forms, and the old stocks have been
improved in uniformity and conformity to type. The principal other
improvements made have been in securing somewhat thicker flesh and
increased earliness. These improvements have been effected almost
entirely by private agencies.
TOMATOES, PEPPERS, AND EGGPLANT 189
The list of practically all really distinct sorts noted by Tracy
(46, 47) follows:
Pungent varieties — Mild varieties —
Bird's Eye Bellior Bull Nose
Cayenne Black Nubian
Celestial Chinese Giant
Cherry Golden Dawn
Large Red Chili (or Mexican) Golden Giant
Red Cluster Monstrous (or Grossum)
Small Chili (Red Chili) Ruby King-
Tabasco Squash or Tomato
Yellow Cayenne Sweet Mountain
Yellow Cherry
Until recently most of the hot varieties were the same as when
they were first found by Europeans over 400 years ago. One type,
however, has been a subject for improvement since about 1900. The
large, long, hot type variously known as a Cayenne or Mexican type,
or just as plain Chili, is a very important vegetable in the Southwest.
This should not be confused with either the very hot Cayenne variety
or the very hot small Chili pepper that is used in making pepper
sauce. It is a large elongate sort that is eaten green or ripe and used
fresh, canned, or dried.
In 1903 Musser (14) introduced Anaheim Chili, named for the town
of Anaheim, Calif., an important center of production and drying of
this type of pepper. It was developed by mass selection from the
Mexican Chili for longer, thicker-fleshed pods. It is still an important
variety.
About 1917 Garcia (16), of the New Mexico Agricultural Experi-
ment Station, introduced Chili No. 9, also a selection from the native
Mexican type. He selected specifically for larger size, thicker flesh,
a sloping shoulder to facilitate peeling, productivity, and general
adaptability to canning under New Mexico conditions; Incidentally,
he obtained an intermediate resistance to fusarium wilt. The strain
has replaced most of the older ones grown in the warmer parts of
New Mexico.
Recently, by pure-line selection, Miller, of the Louisiana station,
has developed a number of highly uniform, intensely colored, produc-
tive strains of very hot peppers of the Tabasco and Cayenne types.
The production of Tabasco peppers for making Tabasco pepper sauces
is an important industry in Louisiana. In 1935 Miller distributed
Tabasco 10-1 and Tabasco 10-2. These were developed from the
locally grown strains of the variety. Sport was distributed in 1936.
It was developed by crossing the local Sport X Honka, an intensely
red Japanese variety, then backcrossing to Honka in an effort to
further intensify color. A fourth production of Miller's isSelection
C-28-11, derived by inbreeding from a locally grown strain, Baton
Rouge Cayenne. He selected for superior earliness, greater pungency,
yield, and resistance to cercospora leaf spot.
Although the sweet varieties are much more important commer-
cially than the hot varieties, less attention has been given to them by
public research agencies in the United States. This is doubtless
190 YEARBOOK, 1937
because of the keen interest private agencies have shown in the sweet
peppers and the very satisfactory contributions they have made.
Two sweet varieties of pepper have been introduced by experiment
stations, but so recently that it is impossible now to indicate their
probable importance. The Waltham Field Station of the Massa-
chusetts Agricultural Experiment Station introduced Waltham Beauty
in 1935. It was selected from an unidentified variety. The Con-
necticut station introduced Windsor-A in 1936, developed from a
hybrid of California Wonder X Bountiful. Both of these new intro-
ductions are early, show improved wall thickness, and are adapted
to New England conditions.
Practically all of the large-fruited, mild-fleshed varieties were de-
rived by selection or the finding of valuable segregates of natural
crosses. The pepper is cross-fertilized to a considerable extent, so
that under field conditions natural crosses between varieties may
occur frequently. The parent varieties of most of the commercial
varieties that have been prominent for the past 50 years are unknown
and many of them are relatively old.
As mentioned above, the hot varieties, except for very recent im-
provements that hardly involve major varietal characters, have been
known for 250 to 300 years and even longer. Among the sweet
varieties the names of Bell or Bull Nose, Oxheart, and Squash have
been current for over 150 years. Most of our present sweet varieties
have come from these types. The types were first described about
400 years ago.
Just as the period from 1875 to 1900 was very productive of new
introductions and selections of tomato, so it was with peppers. Al-
though many new names and some improved stocks appeared, few
really marked advances can be recorded. Many of the supposedly
new introductions during that period represented varieties that could
be recognized by detailed descriptions in the literature over 200 years
old. We may be safe in assuming that nearly all varieties known
about 1850 were very old and that about half the "new" varieties
introduced between 1875 and 1900 had been known for 100 to 200
years. Table 1 shows only too well the fragmentary nature of our
present knowledge of the origin of some of the better known varieties.
There are a few varieties that command special interest. Chinese
Giant and Ruby King are doubtless selections out of the old Bell or
Bull Nose, and Chinese Giant represents no very great deviation
from its supposed parent variety. It is rather late, tends often to be
rough, and is only a moderate to shy producer. Ruby King, intro-
duced by Burpee, was a real improvement over the old type, having
more attractive, uniform shape, higher productivity, and better
quality. The chief claim of Chinese Giant to fame was its size.
Ruby Giant and World Beater are two varieties of some importance
that were developed from crosses of Chinese Giant and Ruby King.
Royal King was selected from Ruby King, and Magnum Dulce,
popular for many years, was selected from Chinese Giant. Although
the records are incomplete, it appears almost certain that several of
the more recent introductions also have been selected from one or the
other of these two varieties or from crosses in which one or both were
involved. Ruby King is still one of the half dozen most important
TOMATOES, PEPPERS, AND EGGPLANT
191
sweet varieties and is perhaps more widely grown than any other
single variety. California Wonder is considered the most important
improvement in many years, on account of its large size, attractive
form, uniformity, and very thick, firm flesh. It is rather late, however,
and not well adapted to the northern third of the United States. Harris
Early Giant, introduced by the Joseph Harris Seed Co., is very popular
in the more northerly areas where California Wonder is too late.
Table 1 . — Origin of some of the more important pepper varieties of the United States
Early
referenco
to va-
riety
Varietal history in United States
Name
First
described
or adver-
tised
Origin
1903
(')
1991
1828'
1887
(')
1887
W
«
1900 2
1892
1890
1882
1906
1887
1920
1890
(0
(0
1904
1867
1903
1895
1917
1844
1912
1918"
1006
1884
(')
1922
1849
(0
1935
1919
Bell (or Bull Nose)
1774
1753
Precolonial; New World.
1542
1731
1686
1588
Cherry .- ..
Chilli (or Chili)
Precolonial; New World.
Do.
Selection from Bell (?) .
1640
1632
1813
1832
Do.
Long Yellow Cayenne
Do.
Selected from Chinese Giant.
Selected from Bell (?).
Nepal Chili
1809
Selected from Spanish "pimiento" by S. D. Riegel.
Squash (or Tomato)
1686
Precolonial; New World.
&Co.
Selected from Bell (?).
Tabasco
1888
Introduced from Mexico.
Chinese Giant X Ruby King.
i Unknown; very old.
2 Approximate date.
The sweet peppers of the Squash or Tomato type are very popular
for home garden and local market use, but are relatively unimportant
in the heavy commercial shipments. Sunnybrook, introduced by
Burpee, is the best known and most important of these. A tempest
raged a few years ago in the horticultural press over claims that
certain varieties of this group represented hybrids between pepper
and tomato. The new names involved in the controversy implied
hybrid origin, and the varieties were advertised and sold with the
claim that they were new hybrids. However, numerous botanists,
horticulturists, and growers who know peppers and tomatoes have
never been able to detect any trace of tomato characteristics in either
the plant or the fruit. The tomato shape proves nothing, for that
192 YEARBOOK, 1937
has been known in peppers for about 400 years. Furthermore, tomato
and pepper belong to such distantly related genera that crossing the
two is believed to be impossible. There is, at least, no convincingly
documented case of such a hybrid known, despite the fact that skillful
workers have often tried to cross them.
Another interesting varietal development is that of the Perfection
pimiento pepper, selected to meet a specific requirement by S. D.
Riegel, of Georgia. The introducer of this variety was engaged in
the canning of peppers and required a very mild, very thick-fleshed
sort having specific qualities of flavor and adaptability to canning.
Since no such variety was grown in the United States at that time, -
he obtained seed of a Spanish pimiento from Spain. The variety
name was not stated, but it was probably Sweet Genua or a closely
related form. From this Spanish stock a single plant was selected
having the desired characters and apparent adaptability to conditions
in the southern United States. The variety Perfection was developed
by selection from the progeny of this plant and first introduced to
the trade about 1912.
EGGPLANT
History
The eggplant, Solarium melongena L., is believed to be native to the
Tropics of the Old World. It was referred to in Chinese writings of
some 1,500 years ago, and by various early writers in the sixth, ninth,
twelfth, and thirteenth centuries (18). It appears to have been un-
known in Europe in ancient times and is therefore believed to be
Asiatic in origin. Vavilov (48) has concluded through his botanical-
geographic studies that there were two centers of origin, the first in
subtropical or tropical India, the second in China.
In the sixteenth century various writers described eggplants of the
several colors known today — purple, yellow, wliite, ash-colored, green,
and brownish. The oblong or elongated, pear-shaped, and round
forms were also known in that early day. At present there is almost
no interest in any but the purple-fruited sorts in the United States,
but occasionally other colors are grown for ornament. There is good
evidence that no new or distinct types have been developed within
historic time, although of course numerous variations or varieties have
been found and propagated within each type. It is probable that
considerable increase in size has resulted from comparatively modern
efforts, because the varieties described early in the seventeenth
century seem to have been rather small. A hundred years later de-
scriptions are found indicating fruit sizes that are comparable with
our present sorts.
Vilmorin-Andrieux & Cie., Paris (49), in 1856 described 7 varieties,
including Long Purple, Kound Purple, Chinese Long White, Large
Purple, and Guadaloupe Striped. Burr (5), in this country, in 1865
listed these same varieties as of interest here, and in addition described
New York Improved. New York Improved and Long Purple are
still among the half-dozen varieties of commercial importance in the
United States today.
The eggplant does not have any great appeal to the majority of con-
sumers in this country, so it remains a minor crop — and probably will
TOMATOES, PEPPERS, AND EGGPLANT 193
so remain for a long time. This general lack of interest is reflected in
the small attention it has received here from plant breeders and inves-
tigators. There are few varieties grown in the United States, and
little is being done to produce new ones. In the Orient, however, the
situation is quite different. The eggplant is one of the most important
vegetables in China, Japan, and India, holding in those countries a
position more nearly comparable with that of the tomato in North
America. Because of its extensive use and popularity in the Orient,
numerous varieties have been developed and it has been the object of
perhaps more genetic and cytological study than in Europe or North
America. Numerous oriental varieties have been introduced for trial
by American growers and seedsmen but have never attracted interest.
Some of them are quite productive, but generally they are of small-
fruited types or of colors that do not appeal to us.
Breeding and Improvement
All our important commercial varieties are the result of work by
private gardeners and seedsmen. Most of them were doubtless ob-
tained merely by selection from the old long-established types and
represent minor improvements except in fruit size and uniformity.
Unfortunately we are unable to determine with certainty the time,
manner, and place of origin of our present varieties.
The white, striped, and scarlet-fruited sorts are all very old and are
of interest only as novelties or ornaments, so they will not be discussed
here.
Of the purple-fruited sorts, Round Purple and Long Purple doubt-
less were imported from Europe a century or more ago. Vilmorin-
Andrieux & Cie. (49) lists Large Purple as of American origin, intro-
duced in 1854. The parentage is unknown.
Burr (5) lists New York Improved, indicating that it was derived
from Large Round. It was described as having spiny leaves. It
appears that the variety was developed by selection about 1850 by
Brill, a gardener and seed grower of Long Island, N. Y., and named
by him. The modern strains of New York Improved are spineless.
Spineless strains have been available since about 1900.
Black Pekin was a popular variety for many years but is now rarely
listed. It was introduced from China about 1870.
Black Beauty appeared about 1900. It is said to have been orig-
inated by Ashcraft, a gardener and seed grower of Swedesboro, N. J.
There is" little question that Black Beauty has been the most popular
eggplant variety grown in the United States. The intensely dark-
purple, or purplish-black, fruits of medium-large size are very attrac-
tive and are largely responsible for its outstanding prominence.
The old Long Purple variety has been the subject of selection for
earliness, particularly in the Northern States. Early Long Purple, or
simply Long Purple, is the earliest variety commonly grown, but is
grown extensively only where earliness is essential.
The most important development since Black Beauty is the Florida
High Bush. It was introduced about 1905 by a Florida grower who
selected it for its tall upright growth and habit of bearing its fruits
well up off the ground. This character is often of considerable im-
194 YEARBOOK, 1937
portance as an aid in avoiding losses from, fruit rots or other damage
resulting from contact with the soil.
The agricultural experiment stations of New Hampshire, Rhode
Island, and Wisconsin are all working for increased earliness in egg-
plant to permit its being grown profitably farther north. The Central
Experimental Farm of Canada, at Ottawa, has introduced Blackie, a
selection smaller and earlier than Black Beauty that is also more pro-
ductive in the North.
Kakizaki {25), in Japan, demonstrated the commercial feasibility
of artificially produced hybrid eggplant from inbreds known to be
superior for the purpose. In 1931 he introduced Black Bountiful, a
first-generation hybrid which has been offered for sale in the United
States by Japanese seedsmen. It is distinctly smaller than our well-
established sorts and so has not become popular here. However, it is
early and very productive.
STUDIES OF INHERITANCE AND CYTOLOGY
IN SOLAN ACEOUS FRUITS6
Tomato
The first investigators (17, 41) of the mode of inheritance of specific
characters in the tomato quite naturally and logically examined certain
of the most obvious features of plant and fruit, such as cotyledon size
and shape, leaflet size and shape, leaflet surface character, plant stat-
ure, growth habit, fruit color, fruit shape, and internal structure of
fruits. Such studies have been made over the last 30 years, but the
most conclusive results have been reported in the last 15 years. J. W.
MacArthur, at the University of Toronto, and E. W. Lindstrom, at the
Iowa Agricultural Experiment Station, are the most active in studying
inheritance in "normal" individuals, while J. W. Lesley and M. M.
Lesley in California, F. W. Sansome in England, besides Lindstrom,
are engaged with cytological studies, induced mutations, polyploidy,
and the occurrence of aberrant forms.
A large number of workers have contributed to the present knowl-
edge of inheritance of specific characters in the tomato, but it is not
necessary to cite here all the literature of all workers. Table 2 pre-
sents a summary of the characters studied to date, with data concern-
ing dominance and indications as to whether the contrasted charac-
ters are due to differences in one or more factors. Most of those
listed represent single factor differences.
Unfortunately, the characters that we most desire to incorporate
into our new varieties to meet new needs cannot be listed in the table
at this time. These are resistance to specific diseases, such as fusa-
rium wilt, verticillium wilt, nailhead, leaf mold, septoria, mosaic,
streak, and curly top. Although there are many varieties showing
a fairly high resistance to fusarium, a few resistant to nailhead, and
resistance to leaf mold, nothing certain is known about the number
of factors involved in resistance to any of these diseases, and there are
only general unconfirmed indications of the dominance or recessiveness
of resistance.
•This section is written primarily for students or others professionally interested in breeding or
genetics.
TOMATOES, PEPPERS, AND EGGPLANT
Table 2. — Inheritance in the tomato
195
Characters
Flesh color:
Bed v. yellow.
Red v. tangerine orange.
Skim
Yellow v. colorless
Dark-green base v. uni-
form green fruit.
Smooth c. pubescent
Shape of fruit:
Globe v. pear _
Short v. elongated
Normal v. fascia ted
Normal !>. nipple-tipped.
Locules in fruit:
2 locules v. many.
Size of fruit:
Large v. small
Plant habit:
Tall p. dwarf
Dwarf v. extreme dwarf-
Tall v. brachytic
Normal v. self-topping.
Leaves:
Qreen t>. yellow color. . _
Norma] v. potato leaf— _
Normal v. wiry-
Normal v . wilty.
Normal v. hairless.
Inflorescence:
Simple r. complex.
Normal v. leafy
Stem color:
Purples, green
Purple v. becoming green .
Time of maturity:
.Early p. late
Pedicel:
Jointed v. nonjointed
Hereditary radium-
induced mutations of
Lindstrom:1
Leaves:
Normal v. rough
Normal v. yellow
Cotyledons:
Normal v. rolled
Sterility:
Normal ». sterile
Seedlings:
Normal v. yellow
(lethal)
Normal v. virescent
white.
Genes
R-r
r-t
Y-V
XJ-u
P-p
O-o
I'-f
N-n
Di-di
Di-iii
B,-br
Sp-sp
JA
C-c
W-w
Wt-
Wl
11-h
S-t>
Lf-lf
Ai-ai
Ai-ai
J-i
Ri-ri
L-l
Rc-r.
Sr-s,
Y.-V.
V-v
Behavior
inFi
Bed..
....do
Yellow
Dark-green
base.
Smooth
Globe..
Short-
Normal.
....do..
2 locules—
Intermediate
Tall
Dwarf-.
Tall
Normal.
Green— .
Normal -
.do.
.do.
.do.
Simple..
Normal.
Purple.
do-
Intermediate
Jointed- ..
Segregation in F2
3 red to 1 yellow.
3 red to 1 tangerine
orange.
3 yellow to 1 colorless.
3 dark green to 1
uniform.
3 smooth to 1 pubes-
cent.
Gradations. Tend
toward 3:1.
3 short to 1 elongated .
3 normal to 1 fasciated
3 normal to 1 nipple-
tipped.
Approximately 3:1-—
All gradations
3 tall to 1 dwarf
3 dwarf to 1 extreme
dwarf.
3 tall to a brachytic..
3 normal to 1 self-
topping.
3 green to 1 yellow
(lutescent) .
3 normal to 1 potato
leaf.
3 normal to 1 wiry. . .
3 normal to 1 wilty...
1 normal; 2 interme-
diate; 1 hairless.
3 simple to 1 complex.
3 normal to 1 leafy. .
3 purple to 1 green. .
3 purple to 1 becom-
ing green.
All gradations
3 jointed to 1 non-
jointed.
| Tetraploid
Authoritv segregation
Autnontj . (afterSan.
some, 44)
(17,29,34,87,40
(.Si, ST)
(17, i9, 34,87, 40
(S7)
(17,29,84,87)...
(34,37)
(S9, 34, 37) _
(34,37)
(Si, 37)
(40 -
(89, 30,30, 37, H)
(17,29,37, il)-..
(Si, ST)
(Si, 87).
(Si,S7).
(17, 34, 37, 41).
(17,34,87,41).
(34, 87).
(84,87).
(34,87).
(S4, 37).
(34,87).
(34, 37).
(34,37).
(7).
(6).
Between 22:1
and 35:1
Approxi-
mately
35:1.
Approxi-
mately
22:1.
Approxi-
mately
22:1.
Approxi-
mately
22:1.
1 All 6 characters monorecessives; / shown to be same character previously known (32).
196 YEARBOOK, 1937
Several difficulties have stood in the way of acquiring this much-
needed information. First, strong resistance to certain of these
diseases is at present unknown in any form of tomato. Wide search
has yielded no appreciable resistance to mosaic, streak, or curly top.
And in those cases where a degree of resistance is known, it is usually
such an intermediate or partial resistance that it cannot be measured
with any dependability. Until methods are developed that will
permit accurate determination of the amount of resistance in a plant,
under even a single set of reasonably standardized experimental con-
ditions, progress will necessarily be slow. It must be possible to
repeat tests with given stocks and get results that will consistently
agree if we are to know much about resistance.
Another difficulty is space requirement and cost of conducting such
tests with the tomato. Thousands of small-grain plants or peas can
be tested on a few square rods of land or a few benches in the green-
house; but in the field, 15 to 20 square feet is needed for each tomato
plant, and 3 to 4 square feet of precious space in the greenhouse.
The worker with small plants can test thousands or hundreds of lines
where the tomato investigator can handle only hundreds or dozens.
There also has been too much pressure for quick practical results,
and many workers have felt it necessary to hurry without being able
to make the desirable and often essential preparatory surveys and
studies. Now a number of research agencies are backing up for a
new start, but they are first carefully preparing to ferret out essential
basic information before launching further into practical application
of research. It is hardly possible to apply what isn't known.
In his quest for leaf -mold resistance, Alexander (/), at the Ohio
station, has isolated apparently homozygous resistant lines from
segregating progenies of a cross between an off-type resistant plant
and the variety Marliio. The off -type plant bore very small fruits
on simple inflorescences and appeared to be from a chance cross with
the Red Currant variety. Von Sengbush and Loschakowa-Hasen-
busch (45) have reported that Solanum racemigerum Lange (known
in the United States as Lycopersicon pimpinellvfolium Mill.) is com-
pletely resistant to leaf mold and that resistance in this species is
due to a single dominant factor. They have also reported a recessive
form of resistance in the variety Stirling Castle. Alexander's data,
although admittedly meager and not taken as part of a genetic study,
also indicate a recessive resistance in Stirling Castle and a dominant
resistance in Satisfaction, another English greenhouse sort.
D. R. Porter, at the California station, has noted appreciable
resistance in L. pimpinellifolium to western yellow blight, a virus
disease, and is attempting through crossing and backcrossing to
incorporate the resistance rapidly into acceptable commercial types.
He is also studying the genetics of resistance.
Porte and Wellman, of the Bureau of Plant Industry, found one
line of Lycopersicon pimpinellifolium, when grown in heavily artificially
infected fusarium wilt soil, to be practically immune to wilt and highly
resistant to a number of leaf diseases. They used a technique similar
to Porter's in order to transfer higher degrees of fusarium resistance
to commercial sorts than they commonly carry. By controlled pol-
lination they have also developed a large number of inbred lines of
TOMATOES, PEPPERS, AND EGGPLANT
197
commercial varieties resistant and susceptible in all degrees. This
was preparatory to determining the nature of such disease resistance
as the lines possessed, which might be used in further breeding. It
has not been possible to observe consistent percentages of resistant
and susceptible individuals in repeated tests of a stock or line, or con-
sistent degrees of injury to the plants in repeated inoculation tests.
The effects of the texture, moisture, hydrogen-ion concentration, sol-
uble salts, temperature, and fusarium content of the soil, the temper-
ature and humidity of the air, the effect of light, age, and size of plant,
and other such factors upon infection and reaction of the plant to the
parasite are almost if not entirely unknown. These must be learned
and test conditions properly standardized before dependable compar-
isons of resistance can be made. Special studies are, therefore, in
progress in efforts to perfect a technique for dealing with the incom-
plete type of fusarium resistance, the only type definitely reported to
date.
C M. Tucker, at the Missouri station, has recently reported to the
writer that among many seed lots of Lycopersicon pimpinellifolium
tested, one appears to possess complete dominant resistance to fusa-
rium wilt. Other lots either were 100-percent susceptible or showed the
intermediate resistance that is typical of resistant commercial vari-
eties. At this writing his studies have not proceeded far enough to
determine more.
A number of other investigators are busy with disease resistance
and with selection for improved adaptation to specific requirements,
but reports are not now available as a basis for discussing their work.
(See list of projects and workers in the Appendix.)
Wellington (51 ) reported yields of ¥x intcrvarietal hybrid tomatoes
about 21 percent higher than the yields of the more productive parent,
45 percent higher than the mean of the two parents, and 71 percent
higher than the lower yielding parent.
Linkage in the Tomato
Thus far, the chromosome map of the tomato hardly has its outlines
well drawn. MacArthur (34, 85 } 86, 37) and Lindstrom (29, 80, 83)
have made the major contributions to knowledge of this problem.
Of some 20 genes that are known, the positions of 16 have been located
on 10 of the 12 pairs of chromosomes. Six of the groups now contain
two or more known genes.
The chromosome map showing the linkage groups and the probable
order of the genes within the groups may be represented roughly
as follows:
Chromosome Genes
Chromosome
(ienes
I
Di-P-O-S (arid genes for
VI
L (and genes for earl
earliness ?).
ness and size ?).
11
R (?).
VIT
V-H-T.
III
Br-Y.
VIII
A* (?).
IV
C-Sv.
IX
r>2 (?).
V
F-Ai-Li-J.
X
Wr-N.
The second, sixth, eighth, and ninth chromosomes each bear but
one known factor.
198 YEARBOOK, 1937
Currence (7) has recently pointed out a relation between genes of
the DiPOS region of the first chromosome and genes affecting earliness.
The actual nature of the factors involved has not been determined,"
but T) and DP lines were, on the average, 9 and 14 days earlier respec-
tively than corresponding d and dp progenies.
MacArthur (36) has also recently added evidence of a possible
linkage of genes for earliness and size — if there are such — with certain
qualitative factors. He showed that I, a recessive gene for yellow-
green foliage, retards maturity about 2 weeks and reduces fruit size
30 percent. The author recognized that the existence of size and
earliness genes linked with I was not demonstrated, for the effect
might possibly be due directly to I or other genes. It is logical to
suppose that I, would have a marked direct effect on plant and fruit
development.
It is unfortunate that we do not yet have accurate information
regarding inheritance of disease resistance and possible linkages with
qualitative genes. Some observations might lead us to suppose that
at least certain types of resistance are linked closely with specific
Cytology of the Tomato
Thus far very little if any attention has been given to the cytology
of hybrids of Lyeopersicon esculentum Mill, and related species. The
large number of small chromosomes make cytological study quite
difficult. In the intensive drive for disease resistance, however, it
seems sure that wider and wider crosses will be attempted, with the
failures, sterilities, and various aberrations that accompany such
efforts. Workers will then find it necessary to study both the normal
and the abnormal material cytologically more than has been done in
the past.
Most of the cytological work done on the tomato has been in the
study of triploids, trisomies, and both natural and artificially induced
tetraploids. All three of these chromosomal aberrations occur rather
frequently in cultivated fields and may become evident through the
departure of the plant from the typical vegetative form and fruitful-
ness of the variety in which the aberrations appear. A number of
these have been described in detail by Lesley (26, 27), Lindstrom
(31), and others. In general the plants are characterized by a sturdier,
stockier appearance; thicker, more rugose leaves; and little or no
fruit. They generally produce a large proportion of abortive pollen
and may be unfruitful for that reason if not for others.
The normal n number of chromosomes hi the tomato is 12, and the
2n or somatic number is 24. Aberrant plants have been found with
25, 26, 27 (aneuploids), 36 (triploids), and 48 (tetraploids) somatic
chromosomes, and also some with fragments of additional chromo-
somes. Lesley (27) has obtained 12 different simple trisomies, each
with a different supernumerary chromosome, by crossing a triploid
(2ft=36) plant with a normal diploid (2n=24). He has identified
these as Triplo-A, Triplo-B, Triplo-C, etc., depending on which one
of the 12 chromosomes occurred as a supernumerary. These identifica-
tions of extra chromosomes and the determinations of trisomic ratios
in the progenies of hybrid trisomies have afforded additional confirma-
tion of the connection between genes and chromosomes and may add
TOMATOES, PEPPERS, AND EGGPLANT 199
to knowledge of linkage relations. An understanding of what is hap-
pening to the chromosomes of those aberrant plants helps to make it
clear why they will not breed true and why it is so difficult, if not
impossible, to make practical use of certain desirable characters that
some of them have.
Several workers — Winkler (52), Jprgensen (23), Sansome (44), and
others — in addition to those already named have induced the for-
mation of tetraploids by cutting off stems of plants. Callus tissue
rapidly forms under proper conditions, and in this tissue cells are
occasionally formed with 48 instead of 24 chromosomes. Some of
these cells may develop into shoots and continue growth in a more or
less normal manner. Since these tetraploids are usually nearly sterile
or quite so, and since they do not breed true, they are usually prop-
agated vegetatively for experimental purposes. Thus far there is
no proved case of a commercially valuable tetraploid.
Lindstrom (81 ) has reported a highly fertile tetraploid of Lycopersicon
pimpineUifolium obtained from callus tissue, but it is apparently the
only such case noted. Some are inclined to believe that the parent
plant was not homozygous but that L. escvlentum was involved. The
tetraploid was cross-sterile with the parent type.
A variation with less than the normal number of chromosomes has
also been observed. Lindstrom has described a haploid tomato (12
somatic chromosomes as well as 12 in the germ cells). It was found
in the F2 of a varietal cross of completely fertile varieties. The hap-
loid was smaller than normal and almost completely sterile. Its
pollen was apparently impotent and few seeds were borne when other
pollen was applied to its flowers. There was no tendency to pairing
of the chromosomes, but evidence of a tendency toward reduction or
separation in the meiotic division. It appeared that any germ cell
receiving less than 12 chromosomes aborted.
A few diploid cells were noted in roots, so the plant was carefully
perpetuated by cuttings in the hope that doubling might occur in a
cell destined to become a growing tip and thus give rise to an abso-
lutely homozygous tomato. Not only diploid but tetraploid plants
were finally obtained.
Lesley and Lesley (28) have obtained tomato plants bearing frag-
ments of single chromosomes by crossing a double trisomic (2n+l + l
chromosomes) with a normal plant. Certain of the progenies of this
cross variously contained 2w+l, 2n+l+a fragment or 2n+a frag-
ment. These fragments or incomplete supernumerary chromosomes
represent a partial trisomic condition. Such plants resemble certain
trisomies. It has been found that fragmentation occurs in those un-
paired chromosomes that lag behind in the course of meiosis.
The results of chromosome injury or of "knocking out" factors from
chromosomes by irradiation may well be considered at this point.
Lindstrom (82) irradiated various portions of tomato plants with
radium-bearing needles. Irradiation of growing tips induced the
most variations in the progeny of the treated plants. The irradiated
parent plants showed no sudden variation except what could be ac-
counted for as a result of direct injury by the radium in cases of over-
dosage. The progeny of these plants, however, showed much sterility,
200 YEARBOOK, 1937
pollen abortion, and malformation, supposedly caused by chromosome
damage.
From these progenies Lindstrom isolated six variations that bred
true and were shown to be due in each case to a single recessive factor.
Five of these never before had been observed in tomato, while I for
yellow foliage was shown to be the same factor that had been known
for many years (table 1).
MacArthur (88) accomplished somewhat similar results by irradiat-
ing seeds with X-rays. All plants and fruits from these seeds were
normal, but their progeny showed 12.4 percent of mutants of diverse
forms — all of them economically worthless. There were many lethals
and semilethals among them, only about a dozen being capable of
perpetuation in the homozygous condition. Most of the variations
appeared as chlorophyll and leaf abnormalities, and the plants were
very slow-growing. Most of the new characters susceptible of genetic
study, as in Lindstrom's radium-induced variations, behaved as single
recessive factors. _
Pepper
The principal contributions to the knowledge of inheritance in the
pepper have been made by Halsted (17), Webber (50), and Dale
(8, 9, 10) in this country, Ikeno (20, 21) in Japan, Atkins and Sherrard
(2) in England, and Deshpande (11) in India. These workers are in
general agreement on the inheritance of a number of characters but
disagree on others. In cases of disagreement it appears that the more
recent workers are probably more nearly correct because they have
fenerally used larger progenies and have studied the results in F3 and
ackcross generations as well as in the Fi and F2 generations. In
some of the earlier work the importance of environment in its effect
on expression of specific characters was not fully appreciated and diffi-
culties were encountered. In table 3 are presented data on the inher-
itance of 16 characters in pepper. Conflicting data are not presented ,
but only those believed to be most dependable as indicated by the
respective experimental procedures.
All investigators of foliage and flower color agree on the dominance
of purple A over nonpurple a and on the close linkage or identity of
factors responsible for foliage and flower color. Deshpande (11), how-
ever, only recently pointed out the effect of a second factor for purple
foliage, an intensifier, B, which is without effect when A is absent.
Numerous workers agree that red color of the ripe fruit is dominant
over yellow and that green color of the immature fruit is dominant
over yellow. Each is due to a single factor. Again Deshpande (11)
contributed new information when he showed the effect of A upon
fruit color. Plants with purplish-red fruit crossed with pure yellow
gave four color types in a typical dihybrid 9:3:3:1 ratio in the F2,
namely, purplish red, pure red, yellow overcast with purple, and pure
yellow. He also pointed out a close association between fruit color
and seed color. Bed fruits bear reddish-yellow seeds, while yellow
fruits bear light or pale yellowish seeds.
Dale (8) plotted size distribution curves of pod lengths of Ft and F2
progenies of Coral Gem X Anaheim Chili (short X long pod) and cer-
tain backcrosses. The curves were skewed when plotted against class
intervals of equal arithmetical magnitude,butwerenormalwhen plotted
TOMATOES, PEPPERS, AND EGGPLANT
201
on a logarithmic basis. It was concluded that the several undetermined
factors for pod length exerted proportionate rather than additive
effects, and that there was no disturbing influence of dominance.
Table 3. — Inlieritariee in the pepper (Capsicum annuum)
Characters '
Genes
Behavior in .Fi
Segregation in Fa
Investigators
Plant habit:
Normal v. dwarf..
Flower color:
Violet v. white. --
Normal
Intermediate violot..
3 normal to 1 dwarf.
3 violet to 1 white. .-
Foliage and stem color: '
Purple v . nonpurple
Intense v. normal purple-
Fruit colore
Red ». yellow or orange..
Green «>. yellow (imma-
ture).
Fruit shape:
Blunt v. nonblunt apox._
Bulged v. nonbulged
base.
Fruit position:
Pendent v. ereel
A-a
B-b
R-r
Intermediate purple
Intermediate purple (in-
tensifler only) .
Red...
Green.
3 purple to 1 nonpurple.
Together with A gives
1:3:8:4, three grades
purple, 1 nonpurple.
3 red to 1 yellow or
orange.
3 green to 1 yellow
Fruit calyx: 4
Nonclasping v. clasping..
Fruit flavor:
Pungent v. mild
Fruit size and shape:
Large v. small
Elongate v. globose
Pedicel length:
Shorty, long
Pubescent foliage:
Pubescent v. glabrous.
Inflorescence:
Nonumbel v. umbel- . .
D-d
F-f
P-p
E-e
Intermediate..
Bulged
Mostly pendent..
Nonclasping
Pungent
Intermedia te.
do
Short
Intermediate..
Nonumbel
3 not blunt to 1 blunt. .
3 bulged to 1 nonbulged.
3 pendent to 1 erect
3 nonclasping to 1 clasp-
ing.
3 pungent to 1 mild
All grades
Many grades; 3 factors
indicated.
3 short to 1 long.
15 pubescent to 1 gla-
brous.
3 nonumbel to 1 umbel-
Dale (10).
Ikeno (W),Desh-
pande (//).
Deshpande (//).
Do.
Several.
Webber (SO),
Deshpande
Deshpande (11).
Do.
Deshpande (11),
Kaiser (2h).
Deshpande (11).
Webber (SO).
Several.
Deshpande (11).
Do.
Ikeno (SO).
Do.
1 Hybrid vigor pronounced in plant vigor, height, yield, increased earliness, and fruit diameter (Desh-
pande (11). Length of pedicel, petal, and fruit linked with plant color and fruit position; these in turn
linked with fruit color. AH these factors on 1 chromosome (Deshpande (11)).
2 Purple of sterns and foliage closely linked with flower color; A affects fruit color, giving typical dihybrid
ratio 9:3:3:1 in F2.
3 Seed color closely linked with flesh color.
* Nonclasping calyx closely linked with bulged base; 3 percent cross-over.
Branching habit, leaf size, and fruit size were shown by Webber (50)
and others to be controlled by several factors, as evidenced by the
intermediate character of the P\ and the occurrence of all gradations
of habit or size in the F2.
Kaiser (24) showed the hereditary position of the fruit (pendent v.
erect) to be due to a response to geo tropic stimulus rather than
orientation with reference to the plant axis or branch. A single
dominant factor is responsible for the pendent position.
Dale (10) studied a leaf variegation in the pepper, which he found
to be inherited maternally. Ikeno (21) observed other variegated
forms in which the variegation was transmitted by either male or
female gamete. Selfing of these races yielded only variegated off-
spring. Crossing variegated with green resulted in dilution of the
variegated character. Cytoplasmic transmission is thought to have
138904°-— 37 -14
202 YEARBOOK, 1937
been involved in both these instances. Other workers dealing with
other plants have reported many cases of apparently cytoplasmic
inheritance, particularly in cases of leaf variegation.
With one exception, all reports on the chromosome number of popper
are in agreement. Kostow, according to Huskins and La-Cour {19),,
reported a haploid number of 6 for Capsicum annuum, but later workers
have consistently reported 12. Huskins and La-Cour (19) studied a
dozen varieties among three subspecies and found only normal figures
of 12 chromosomes in the haploid and 24 in the diploid states. Dixit's
(12) results agreed with these.
No such interesting observations of polyploidy have been made in
pepper as in tomato. It can hardly be said that polyploidy does not
occur in pepper, but a search of recent literature failed to reveal record
of studies of polyploids or chromosomal aberrations in this plant.
Cases will come to light as the cytologist turns more attention
to it, no doubt, for the family Solanaceae is one of the most produc-
tive of these types of variation.
Eggplant
As mentioned above, the eggplant has been studied very little from
the cytogenetic standpoint, and most of the work done has been by
other than United States investigators.
Halsted, of New Jersey (17), Nolla (39), of Puerto Eico, studying
at Cornell University, and Kakizaki, in Japan (25), have studied the
inheritance of color.
Halsted found two pairs of genes for fruit color. Purple skin v.
colorless skin is due to a single dominant gene, as is also green flesh v.
white flesh. He obtained four color types — PO purple (purple skin,
green flesh), Pg pink (purple skin, white flesh), p6 green (colorless
skin, green flesh), and pg white (colorless skin, white flesh). He also
studied a variegated fruit color that he found to be recessive.
Nolla confirmed Halsted's studies on fruit color and extended his
observations to leaf and stem color, corolla color, and a striping of the
anther. He found purple color in vegetative and floral parts to be
either very closely linked with fruit color and with each other or con-
trolled by the same gene. Without exception fruits with purple skins
were borne on plants with violet or purple corollas and purple-tinged
foliage. Green-fruit forms were borne on pure green plants with
white corollas. Violet or purple corolla v. white was due to a single
dominant factor, as was striping v. nonstriping of the anther. Mono-
hybrid ratios in close conformity to the theoretical were obtained in the
F2 for all these characters.
In his studies of hybrid vigor in eggplant, Kakizaki (25) determined
the seed and fruit weights, stem diameters, and heights of some 30
interparietal crosses. He also recorded the Fi behavior with reference
to branching habit, leaflet size, fruit shape, color, and occurrence of
calyx spines.
In the Fi generation branching, leaflet size, fruit shape, and calyx
spines were intermediate between the parents. Purple skin was
dominant over white.
The mean seed weight of 30 crosses was 18 percent heavier than that
of the mother parents. These results were generally consistent in 3
TOMATOES, PEPPERS, AND EGGPLANT 203
successive years, and were compared with selfed maternal parent
seeds grown in the respective years.
The Fx plants showed a mean stem diameter and height increase of 6
percent over the mean of the parents, and 36 percent increase in yield.
The Fi progenies were 70 percent more productive than the lower
yielding parent and 17 percent more than the higher yielding parent.
The hest two parents for crossing gave Ft progenies 90 percent more
productive than the standard. Other Japanese workers have also
noted marked hybrid vigor in eggplant. This work led to the com-
mercial production of hybrid seed mentioned above.
It does not follow, however, that all interparietal crosses will prove
to be subsequently productive in all respects. Rao Balaji (48) has
noted a high degree of partial sterility in the Fx plants of certain wide
crosses of Indian varieties. The pollen was 90 to 95 percent abortive.
Yasuda (53) has induced the formation of fair-sized parthenocarpic
eggplant fruits by pollinating the flowers with petunia pollen. Cyto-
logical study showed that the petunia pollen tubes never reached the
micropyle of the eggplant ovule, indicating that the stimulus of polli-
nation alone induced ovary development. Injections of an extract of
petunia pollen into ovarian tissue of the eggplant produced a similar
effect, but tomato pollen extract was less effective.
The haploid chromosome number of eggplant is 12, the diploid 24.
A few cases of polyploidy have been observed, but thus far none has
any economic value. Janaki Ammal (22) found a tetraploid in a
field culture that was nearly barren. Among the progeny of this
tetraploid, triploids (36 chromosomes), tetraploids (48), and aneu-
ploids of 44 to 46 chromosomes were found. He concluded that the
triploids arose from a diploid pollen grain. Selling of one of the trip-
loids yielded 14 seeds, which produced 13 living plants. Of these, 2
were tetraploids and 11 were near-tetraploids, the counts of which
could not all be determined with certainty. All these plants with
aberrant chromosome numbers were decidedly undesirable from an
economic standpoint and were almost entirely sterile.
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1934. leap mold resistance in the tomato. Ohio Agr. Expt. Sta. Bui.
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1896. survival op the unlike; a collection op evolution essays
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1933. descriptions op types op PRINCIPAL AMERICAN VARIETIES op
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DESCRIPTIONS OP NEARLY ELEVEN HUNDRED SPECIES AND VA-
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1936. inherited characters in the tomato. ii. jointless pedicel.
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YEARBOOK, 1937
CuRRENCE, T. M.
1934. GENES IN THE FIRST CHROMOSOME OF THE TOMATO AS RELATED TO
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Dale, E. E.
1929. inheritance of fruit-length in capsicum. Mich. Acad. Sci.,
Arts and Letters Papers 9: 89-110, illus.
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1931. maternal inheritance in a chlorophyll variegation in
capsicum. Mich. Acad. Sci., Arts and Letters Papers 13: 5-8,
illus.
Deshpande, R. B.
1933. studies in Indian chillies. (3) the inheritance of some
characters in capsicum annuum l. Indian Jour. Agr. Sci.
3: 219-300, illus.
Dixit, P. D.
1931. a cytological study of capsicum annuum. Indian Jour. Agr.
Sci. 1 : 419-433, illus.
Edgerton, C. W., and Moreland, C. C.
1920. tomato wilt. La. Agr. Expt. Sta. Bull. 174, 54 pp., illus.
Erwin, A. T.
1932. the peppers. Iowa Agr. Expt. Sta. Bull. 293, pp. [120]-152, illus.
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Garcia, F.
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Halsted, B. D.
1918. COLORS IN VEGETABLE FRUITS. TOMATO, EGGPLANT AND PEPPER,
BELONGING TO SAME FAMILY, HAVE SIMILAR GROUPS OF SIMPLE
color factors. . . . Jour. Heredity. 9: 18-23.
Hedrick, U. P., ed.
1919. sturtevant's notes on edible plants. 686 pp., illus. Albany.
(N. Y. Dept. Agr. Ann. Rcpt. 27, v. 2, pt. 2.)
Huskins, C. L., and La-Cour, L.
1930. chromosome numbers in capsicum. Amer. Nat. 64: 382-384.
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1913. STUDIEN uber die bastarde von paprika (capsicum annuum).
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1934. polyploidy in solanum melongena linn. Cytologia [Tokyo]
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J0RGENSEN, C. A.
1928. THE EXPERIMENTAL FORMATION OF HETERAPLOID PLANTS IN THE
genus solanum. Jour. Genetics 19: 133-211.
Kaiser, S.
1935. THE inheritance of a geotropic response IN CAPSICUM FRUITS.
Bull. Torrey Bot. Club 62: 75-80, illus.
Kakizaki, Y.
1931. HYBRID VIGOR IN EGG-PLANTS AND ITS PRACTICAL UTILIZATION.
Genetics 16: 1-25, illus.
TOMATOES, PEPPERS, AND EGGPLANT 205
(26) Lesley, J. W.
1926. THE GENETICS OF I/YCOPEBSICUM ESCULENTUM MILL. I. THE
teisomic inheritance of "dwabf." Genetics 11: [352]-354,
illus.
(27)
1928. A CYTOLOGICAL AND GENETICAL STUDY OF PROGENIES OF TRIPLOID
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(28) and Lesley, M. M.
1929. CHROMOSOME FRAGMENTATION AND MUTATION IN TOMATO. Gc-
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(29) LlNDSTROM, E. W.
1928. LINKAGE OF SIZE, SHAPE, AND COLOR GENES IN LYCOPERSICUM.
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(30)
(31)
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(33)
1931. FRUIT SIZE AND SHAPE GENES ON THE FIRST CHROMOSOME OF THE
tomato. Iowa Acad. Sci. Proc. (1929) 36: 189-190.
1932. A FERTILE TETRAPLOID TOMATO CROSS-STERILE WITH DIPLOID
species. Jour. Heredity 23 : 115-121, illus.
1933. HEREDITARY RADIUM-INDUCED VARIATIONS IN THE TOMATO. Jour.
Heredity 24: 129-137, illus.
1935. SEGREGATION OF QUANTITATIVE GENES IN TETRAPLOID TOMATO
HYBRIDS AS EVIDENCE FOR DOMINANCE RELATIONS OF SIZE CHAR-
ACTERS. Genetics 20: 1—11.
(34) MacArthuh, J. W.
1931. LINKAGE STUDIES WITH THE TOMATO. III. FIFTEEN FACTORS IN
six groups. Roy. Canad. Inst. Trans. 18: 1-19.
(35)
1932. INHERITED CHARACTERS IN THE TOMATO. I. THE SELF-PRUNING
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(36) -
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(37) MacArthuh, J. W.
1934. linkage groups in the tomato. Jour. Genetics 29: [123J-133.
(38)
1934. x-ray mutations in the tomato. Jour. Heredity 25: 75-78.
(39) Nolla, J. A. B.
1932. inheritance of color in the eggplant (solanum melongena l.).
Jour. Dcpt. Agr. Porto Rico 16: 19-30, illus.
(40) Norton, J. B. S., and Hunter, H. A.
1933. tomato diseases and their control. Md. Agr. Expt. Sta. Bull.
345: 490-494.
(41) Price, H. L., and Drinkard, A. W., Jr.
1908. inheritance in tomato hybrids. Va. Agr. Expt. Sta. Bull. 177,
pp. [17]-53, illus.
(42) Pritchard, F. J.
1922. development of wilt-resistant tomatoes. U. S. Dept. Agr.
Bull. 1015, 18 pp., illus.
(43) Rao Balaji, T. K.
1934. partial sterility IN THE Fi plants of crosses between wide
varieties of the common eggplant (SOLANUM melongena).
Current Sci. 2: 285-286.
206 YEARBOOK, 1937
(44) Sansome, F. W.
[1931]. GRAFT HYBRIDS AND INDUCTION OF POLYPLOIDS IN SOLANUM.
Internatl. Hort. Cong. Proc. 9: 92-99.
(45) Sengbusch, R. v., and Loschakowa-Hasenbusch, N.
1932. IMMUN1TATSZUCHTUNG BEI TOMATEN. VORL&UFIGE MITTEILUNG
UBER DIE ZUCHTUNG GEGEN DIE BBAUNFLECHENKRANKHEIT
(CLADOSPORIUM FULVUM COOCKE) RESISTENTER SOBTEN. Zuchter
4: [257]-264, illus.
(46) Tkacy, W. W., Je.
1902. A LIST OF AMERICAN VARIETIES OF PEPPERS. U. S. Dept. Agr., Bur.
Plant Indus. Bull. 6, 19 pp.
(47)
1903. LIST OF AMERICAN VARIETIES OF VEGETABLES FOB THE YEAES 1001 AND
1902. U. S. Dept. Agr., Bur. Plant Indus. Bull. 21, 402 pp.
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1935. [botanical-geogbaphical principles of selection.) 60 pp.
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1912. preliminary notes on pepper hybrids. Amer. Breeders' Assoc.
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(51) Wellington, R.
1912. influence of crossing in increasing the yield of the tomato.
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(53) Yasuda, S.
1934. the second report on the behavior of the pollen tubes in
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BREEDING AND
IMPROVEMENT
OF CUCURBITS
T. W. WHITAKER, Associate Genelicisl,
I. C. JAGGER, Senior Pathologist,
Division of Fruit and Vegetable Crops
and Diseases, Bureau of Plant Industry
A HE cucurbits — cucumbers, muskmelons, watermelons, pumpkins,
and squash — belong to the family Cucurbitaceae. Botanically they
form rather a homogeneous group. While they are extremely diverse
in fruit and vine characteristics, their floral structures are in many
respects very similar.
In general, the family is characterized by the flowering habit known
as monoecious. A monoecious species or variety is one that bears its
pistillate or female organs of reproduction and its staminate or male
organs in separate flowers, both kinds of flowers occurring on the same
plant. In the Cucurbitaceae the female and male flowers are easily
distinguished, even before they open. The showy corolla, or petals,
of the pistillate flower is attached to the end of an easily recognizable,
small, undeveloped cucumber, squash, or melon as the case may be
(fig. I, A). The male flower is at the end of an ordinary flower stem,
without any enlargement (fig. 1, B). The corolla surrounds the pistils
or the stamens in the respective sexes.
Cucumber, squash, and pumpkin are normally strictly monoecious,
but certain varieties of muskmelon and watermelon show a modifica-
tion of this condition that is termed andromonoecious. An andro-
monoecious plant is one that bears bisexual or complete flowers,
instead of strictly pistillate ones, in addition to purely staminate
flowers.
Although at a cursory glance these bisexual, complete, or hermaphro-
dite flowers appear like ordinary pistillates, examination within the
corolla will show the presence not only of the stigmas but of functional
stamens as well. Such flowers can be self -fertilized by their own
pollen, or by the pollen from a purely staminate flower or from an-
other complete flower on the same plant.
Our knowledge of the genetics of the cucurbits is very meager and
fragmentary. There are several reasons for this. Probably the
most important one is economic. The plants are large, and the space
required to produce the numbers demanded for statistical significance
in genetic experiments is enormous. Recently, however, j>romising
results from systematic breeding programs with melons, watermelons,
and squash have enriched our knowledge of the fundamental genetic
nature of these crops (IS),1 and this in turn should bo useful in further
breeding work.
' Italic numbers in parentheses refer to Literature Cited, p. 231
207
208
YEARBOOK, 1937
Figure 1. — Squash blossoms, structurally typical of the cucurbits: A, pistillate flower
showing undeveloped fruit to which the corolla is attached;
B, stamina te or male flower.
BREEDING RESPONSES AND POLLINATION TECHNIQUE
Studies made by numerous investigators of the cultivated cucurbits
show that the several species are alike in certain breeding responses
and variations in reproductive behavior. These points may well be
treated here, since they seem to apply to the several crops.
Haber (8), working with Des Moines squash, a trailing variety of
Cucurbita pepo L.; Scott {25) with three bush types of C. pepo
(White Bush Scallop, Giant Summer Crookneck, and Zucchini), and
also {23) with muskmelon; Porter {18) with watermelon; Cummings
and Jenkins {3), with Hubbard squash, a variety of C. maxima
Duchesne; and other investigators have shown that loss of vigor does
not necessarily follow as a result of inbreeding these plants. This is
quite contrary to the usual situation with normally cross-bred plants.
Scott and Porter have shown that inbred lines having greater, equal,
and less vigor or size of fruit may all be isolated from a given individual
and that no difficulty may be expected from self-sterility in such
mbreds. The work of Rosa {21), of Scott {25), and of Porter {18)
CUCURBITS 209
indicates that hybrid vigor does not occur as a result of crossing
inbreds — also contrary to what might be expected.
Kosa (20) has sought evidence of metaxenia in muskmelon and
Hibbard (9) in squash, but no such phenomenon was observed in
either case. Metaxenia here refers to an immediate effect of pollen
upon the character of the fruit or gross seed characters.
The constancy of these results for a wide range of varieties among
several species of the cucurbits is rather conclusive evidence against
the loss of vigor from inbreeding or the occurrence of hybrid vigor or
of metaxenia in any of the cucurbits discussed in this article.
Another characteristic common to cucumber, squash, muskmelon,
and certain other cucurbits is the wide variation within varieties in the
ratio of male and female flowers. This ratio is profoundly influenced
in many varieties of cucumber by changes in season (length of day)
and in nutrients (5, 29) ; and in squash by season and load of develop-
ing fruits borne by the plant (24). Under certain unfavorable
conditions some varieties may become almost monosexual (all pistillate
or all staminate), so that the investigator has great trouble in obtaining
the desired set of fruit and seed.
Whitaker (32) has published a brief review of the literature on this
subject, together with data on the typical sex expression of 49 varieties
of cucurbits in 8 species and 4 genera and on deviations from typical
expression in each species. His data showed very wide fluctuations
in the ratio of male to female flowers in the several varieties and
species. He concluded that sex determination in these cucurbits
appeared to conform to Correns' theory as applied to monoecious
flowering plants. According to this theory the gene complex for
maleness may be represented as A and that for femaleness as B;
another gene or complex, which may be indicated as Z, determines
the sequence of activation or expression of A and B. A and B in
themselves are believed to be relatively stable, but Z, which represents
TWELVE years ago, powdery mildew suddenly appeared in
destructive form on melons in the Imperial Valley, Calif., the lead-
ing muskmelon-producing section in the United States. It could
not be controlled by fungicides, and plant breeders began a search
for disease-resistant material. In 3 years of careful testing they
discovered several resistant varieties among melons imported from
India. They were poor melons, but by suitable crosses their
resistance to mildew was bred into good American varieties, and in
another 4 years the first of the hybrids was released to California
growers. Four more years of selection gave Powdery Mildew
Resistant Cantaloup No. 45, which has superior shipping qualities
in addition to disease resistance. This was released to growers
in 1936, and the mildew problem is now largely solved in this area.
210 YEARBOOK, 1937
the factors controlling the expression of maleness and femaleness,
may be responsible for a reaction to environment that results in
stimulation or retardation of A or B within very wide limits.
The pollination technique developed by Porter (18), working with
watermelons, illustrates the general method employed in making
controlled pollinations with flowers of the cucurbits. _ Approximately
24 hours before the flowers open, pistillate and staminate flowers are
selected and covered with small muslin bags (in the case of melons
and cucumbers, 1-pound manila bags are satisfactory). As soon as
possible after the flowers open, the staminate flower is removed and
its pollen is applied to the stigma of the pistillate flower. After
pollination, the pistillate flower is covered with a 1 -pound manila
bag, held firmly in place by string or a paper clip. The pollination
data are written on a tag attached to the flower, or directly on the
paper bag. Several days after pollination the bags are removed, the
fruit is tagged, and its location is marked by a stake.
It has been found unnecessary to cover the staminate flowers with
a bag before they open. By placing a string around the corolla the
flower is prevented from opening, and insects cannot enter. This
eliminates one step in the process and increases the number of flowers
that can be pollinated in a given length of time. Hermaphrodite
flowers that are to serve as the female parent in a cross must not only
be bagged before they reach full bloom but emasculated before the
anthers shed pollen, to prevent self-pollination. Since the anthers
may discharge pollen 24 hours before the flowers open, emasculation
should be done more than 24 hours before opening. Purely pistillate
flowers that require no emasculation need not be bagged before pol-
lination, but the corollas may be tied shut as described above.
CUCUMBERS
The cucumber, Cucwnis sativus L., is supposedly a native of India
(SO), although plant explorers have never been able to discover a
wild prototype. Cucumbers have been cultivated since earliest
antiquity. Reliable records indicate that they were used as food in
ancient Egypt, and were a popular vegetable with the Greeks and
Romans. They are very important staple vegetables among the
Russians and many orientals. In the United States cucumbers are
widely grown in home gardens, in local-market gardens, and on truck
farms for shipping, but in spite of their wide distribution under
cultivation, their commercial importance is not so great as that of
some of the other cucurbit crops.
Varietal Improvement
Cucumbers are usually divided into two classes according to use —
slicing varieties and pickling varieties. This distinction is maintained
even though the slicing variety may be used for both purposes. The
plants of slicing varieties produce a moderate number of medium-
length thick fruits generally with white spines. The pickling varieties
are characterized by the production of very numerous, small, black-
spined fruits. The fruits of most pickling varieties are so small,
while still immature, that they are not adapted to slicing.
CUCURBITS 211
In England, a special forcing type of slicing cucumber is grown in
greenhouses. This type sets fruit without any pollination and the
fruits attain great length — over 2 feet in some varieties. Unless
pollination is insured, the fruits are seedless, straight, dark green, and
generally spineless. American consumers, however, do not like the
huge English type, and American greenhouse varieties are either of
the White Spine slicing type mentioned above or of an intermediate
hybrid type somewhat longer than White Spine and darker green.
Most growers of greenhouse cucumbers in this country use especially
adapted strains; many use their own selections.
With one exception, all of our extensively grown commercial varie-
ties of cucumber are the results of breeding, selection, or introduction
by private growers and seedsmen. Many of the names commonly
listed today are very old and represent varieties introduced from
Europe. The origin of verj^ few varieties is a matter of record, even
in the case of comparatively recent introductions. Confusion in
names is perhaps more extreme in cucumber varieties than in many
other crops because of the ill-defined nature and lack of stability of so
many of the supposed varietal characteristics. Vine habit, bearing
habit, fruit size, shape, and color are all subject to marked variation
under different conditions of culture, making the identification of
varieties difficult. In all cucurbits, natural cross-pollination within
a species complicates the problem of maintaining the purity and
uniformity of stocks and varieties, but mixtures are especially difficult
to detect in cucumbers because many so-called varieties have few
really distinguishing features. With the exception of special green-
house types and novelties, there are probably not over 15 to 20 really
distinct cucumber varieties grown in this country.
It is questionable whether many of the supposedly superior varieties
introduced successively in the last 50 years represented improvements
distinct enough to justify now variety names. Seedsmen and growers
have long attempted to develop varieties that will produce fruits of
good size, uniform cylindrical shape, and attractive dark-green color
before they begin to show signs of full maturity. Color is espe-
cially important because paleness or a yellowish tinge suggests too
advanced maturity. A uniform dark green is most desired, and of
course the flesh must be tender, crisp, and free from objectionable
flavor.
A more recent breeding objective, not yet realized, is to develop
varieties with a wide range of adaptability and resistance to various
adverse conditions that result in low yields and poorly shaped fruits.
Early Cluster, Early Frame, Early Russian, Long Green, and White
Spine were listed by the earliest seed catalogs in the United States,
and have been grown here for at least 125 years. The first three are
small, early, prolific varieties typical of the black-spined type; the
last two bear larger, less numerous white-spined fruits that are more
like the present popular slicing varieties. The origin of none of them
is known.
Improved Long Green is a very long (12 to 13 inches), black-spined,
dark-green, slightly tapered, late variety selected from London Long
Green by D. M. Ferry & Co. and introduced in 1872. Arlington
White Spine, a selection from White Spine that appeared about 1880,
212 YEARBOOK, 1937
is still a leading strain of White Spine. It is about 8 to 9 inches long,
2% inches in diameter, medium green, and has a tendency to turn pale
green or w.hite at the blossom end. Davis Perfect (1905) was origi-
nated by Eugene Davis, of Grand Rapids, Mich., from a cross between
White Spine and Telegraph, an English forcing variety. Davis
Perfect is about 10 inches long, 2}i inches in diameter, white-spined,
smooth, dark green, and distinctly tapered at both ends. Fordhook
Famous, introduced by W. Atlee Burpee & Co. in 1902, was originated
by A. Mclnnis, a grower in Ontario, Canada, who selected it from a
cross of White Spine and Noa Forcing, made about 1894. It is a
t3Tpical White Spine type, showing but little of the Noa Forcing charac-
ter. Early Fortune was selected from a field of Davis Perfect by
George E. Starr in 1906 and introduced by the Jerome B. Rice Seed
Co. This has been an important and popular White Spine type for
many years on account of its desirable size (about 8% by 2)i inches),
attractive cylindrical shape with rounded ends, good retention of
green color, and productivity. Other popular current varieties are
Stays Green or Black Diamond, Klondike, and Longfellow. The
origin of these is obscure.
Deltus, a popular forcing variety, was obtained from a cross be-
tween White Spine and Tailby Hybrid made in 1896, the progeny of
which was later crossed with Long Green. Adelbert Titus, a grower
near Rochester, N. Y., originated the variety. Another popular
variety of the Rochester district is the Irondequoit, developed by
J. H. Wirt & Sons from a cross of White Spine and Telegraph
made in 1904. In 1929 the New York Agricultural Experiment Sta-
tion at Geneva, N. Y., introduced a parthenocarpic (seedless) va-
riety named Geneva. It was developed from a cross of Arling-
ton White Spine X Rochford Market made in 1916. All three of
these are intermediate between the White Spine and the English
types-
It is evident that the old White Spine is involved in the parentage
of nearly all the slicing vazieties grown in this country, both field
and greenhouse types. Except in cases of known hybridization with
Black Spine or English forcing sorts, one might be justified in con-
sidering all our white-spined field types simply as strains of White
Spine.
Of the pickling type, Boston Pickling (1865), Chicago Pickling (about
1880), National Pickling (1929), and Snow Pickling (1906) are by far
the most important. The first two are selections from unknown va-
rieties grown near the places of origin indicated by the names. Snow
Pickling was introduced by J. C. Snow, of Rockford, 111., in 1906.
National Pickling was developed by George E. Starr, of the Michigan
Agricultural Experiment Station (1929), to meet the specifications of
the National Pickle Packers' Association, who cooperated with the
station in the work. The pickle packers desired a variety producing
a large number of small, black-spined, dark-green fruits, similar to
Snow Pickling but more nearly cylindrical or blocky, having the
same diameter well out to the ends instead of being slightly tapered.
These specifications are of special interest to those who pack
pickles in glass containers and desire the most attractive product
possible.
CUCURBITS 213
Disease Resistance
Reference to the appendix at the end of the section on vegetables in
this Yearbook will show that several investigators, both in the United
States and abroad, are trying to develop good commercial varieties
having resistance to one or more of several diseases, particularly
mosaic, downy mildew, and bacterial wilt.
Mosaic is a serious problem wherever cucumbers are grown in the
Central, Eastern, or Southern States, particularly in the areas de-
voted to pickling ATarieties. Losses of 15 to 30 percent of normal
production may be expected annually, and in many isolated cases
much heavier losses occur.
Downy mildew is generally distribiited. It is especially severe in
the South, where it is in effect the dominant limiting factor in cu-
cumber production. The losses usually depend on how early the
disease attacks the plants, for it occurs every year and terminates
harvesting soon after it becomes established in a field. Thorough
spraying two to three times weekly is often an inadequate although a
very expensive attempt at control.
Bacterial wilt is a serious disease, in the Central and Eastern States
in particular. Plant pathologists estimate general losses to be 10
to 20 percent of a normal crop, while often certain fields may be prac-
tically a total loss.
The Bureau of Plant Industry has obtained a number of stocks of
oriental varieties of cucumbers, chiefly from China, Japan, and India,
some of which contain distinctly disease-resistant individuals. Con-
siderable tolerance to mosaic has been found in certain inbred lines,
and in some a measure of resistance to mildew and to wilt. High-
quality American susceptible varieties have been crossed with the
low-quality resistant kinds and the hybrids back-crossed to the
American parents. Inbreeding is also being continued in efforts to
isolate lines that are pure (homozygous) for resistance to specific
diseases.
Bailey and Burgess, at the Maine Agricultural Experiment Station,
are engaged in breed ing cucumbers resistant to scab. This disease
causes very severe losses by spotting the fruits, making them un-
salable, as well as by reducing yields. It is confined almost entirely
to the northernmost States. Inbred lines of commercial varieties are
subjected to artificial inoculation to determine resistance or suscepti-
bility. A number of lines apparently homozygous for resistance have
been isolated. Preliminary studies indicate that resistance is dom-
inant and due to a small number of factors, possibly only one.
MUSKMELONS
It is generally believed that the muskmelon (Cucumis melo L.) is
native to India (SO). Although there are indications that it was in
use about the beginning of the Christian Era, it is not believed to
have been in cultivation in very ancient times.
From its center of origin in northwest India it spread to China and
Japan but has not reached a high state of development in those lands.
To the westward, in Iran (Persia), in Turkistan, and in other regions of
Asia Minor and -about the Mediterranean, it was developed to a very
214 YEARBOOK, 193 7
liigh state of perfection. Columbus first brought the species to the
New World, and the natives of the West Indies and the mainland of
North America quickly adopted it. By 1535 it was grown by the
Indians as far north as Montreal, Canada.
Although the muskmelon is grown in every State, most of the
commercial production is concentrated in a few sections of southern
California, Arizona, Colorado, Texas, Michigan, and Indiana and in
the tri-State area of Maryland, Delaware, and New Jersey.
There is a large number of varieties of muskmelons under cultiva-
tion in the United States. Many of them closely resemble one
another, and improved forms are gradually replacing the older vari-
eties. Muskmelon varieties may be arbitrarily divided into two
classes — (1) shipping or commercial melons and (2) local-market and
home-garden melons. Most shipping varieties produce compara-
tively small fruits with a tough rind and firm flesh and are adapted
for shipping in standardized packages to distant markets. Local-
market melons generally have softer flesh and are often large.
The name "cantaloup" is quite generally used in the United States
to designate the small, oval, netted shipping type of muskmelon.
Much confusion over the term has resulted from the fact that in
Europe it is applied to a different type of melon, a long-keeping sort
with a hard, ridged or warty rind, practically unknown to American
growers (14)- The American usage is now so well established that we
must accept the name cantaloup as defined above. Obviously all
cantaloups are muskmelons, but many varieties and types of musk-
melons are not cantaloups by this definition. The kinds that lie
outside the definition are the winter types, as Persian, Casaba, and
Honey Dew, the Honey Ball, and the large, ribbed sorts like Bender
and Montreal.
Varietal Improvement and Breeding
The number of varieties of muskmelon that have been and are
being grown in this country is so great that no attempt to review the
early history and development of all of them can be made here.
Only the leading present varieties and a few of their supposed pro-
genitors can be discussed, together with a brief reference to certain
kinds that were formerly important.
Prior to 1850 most of the few varieties of muskmelon then grown
inthis country were introduced from Europe. Efforts were begun
prior to that time to improve the crop from the standpoint of adapt-
ability, particularly to the northern part of the country. Increased
earlincss and productivity were of special interest, since most of the
imported varieties then available were apparently from warmer
regions or for greenhouse culture. Nutmeg and Pineapple appear to
have been varieties similar to our present cantaloups, and apparently
the famous Netted Gem — later called Rocky Ford — was derived
from the latter. Pineapple was_ described by Burr (1865) as roundish
to oval, without ribs or with ribs faint, size small, skin olive green
with abundant net markings. Nutmeg was described as slightly
larger, ribbed, and otherwise similar. Both were old well-known
European types. Most sorts described at that time were large,
heavily ribbed, and netted. Numerous melons of the winter Casaba
CUCURBITS 215
or Persian type were described, but there is no indication that they
were important. Most of the supposed American varieties mentioned
by Vilmorin in 1856 were indicated as being related to the "American"
variety Pineapple.
One of the earliest instances of muskmelon improvement in this
country was the origination of the Christiana melon. It was devel-
oped about 1835 by Josiah Lovett, of Beverly, Mass., and is supposed
to have been a cross of the variety Green Malta and an unnamed
early sort. Despite poor quality, it was popular because of its
earliness and was commonly listed for over 75 years.
About 1875 keen interest in muskmelon improvement was shown
by both seedsmen and growers for the market, but the latter were
perhaps the more active in actual selection and hybridization. Little
artificial pollination appears to have been done, but natural crossing
in mixed plantings furnished these growers with an abundance of
material for selection.
About 25 rather distinct varieties besides the winter melons are of
commercial importance or considerable home-garden interest and are
listed by the leading seedsmen of this country at present. About a
third of these are over 50 years old and only a half dozen are less than
25 years old. This survival indicates that the old "practical breeders"
achieved results not easy to surpass and that the introducers brought
in varieties well adapted to cultural conditions and consumer tastes.
In 1901 there were about 25 or 30 fairly distinct and important sorts
commonly listed, and about half of these are still current.
The old Surprise, of unknown origin, was introduced in 1876 and is
supposedly the parent of Bender Surprise, a large, prominently
ribbed sort that is an important home and market melon of the
Northern States today.
The Netted Gem, apparently a form of the very old Pineapple,
was first listed by W. Atlee Burpee & Co. in 1881. Its notably suc-
cessful adaptation to shipping and market needs stimulated a great
deal of interest in obtaining different and still better varieties of the
same general type. Varieties of this typo, with different flesh colors,
slightly different sizes and shapes, and adaptability to different regions,
soon were developed in the commercial muskmelon areas.
In 1886, Acme or Baltimore was introduced by J. Bolgiano, of
Baltimore, and Emerald Gem, by W. Atlee Burpee & Co. Anne
Arundel, introduced by Griffith & Turner, of Baltimore, in 1894, was
believed to have been selected from Acme. About 1905 another
selection, apparently from the Acme-Anne Arundel line of develop-
ment, was introduced under the name of Sweet Air by George Tait
& Sons, of Norfolk, Va. Tliis same variety had been sold in Maryland
as Knight for some years. The two names are known to be synony-
mous and the variety is still widely grown in the Chesapeake Bay
section.
In 1897 the Netted Gem was renamed Rocky Ford to advertise its
merits as grown and shipped by a group in the Rocky Ford, Colo.,
district, whereupon it became more popular than ever. When it
proved to be adapted to the Imperial Valley, that desert area having
been placed under irrigation a few years later, a truly phenomenal de-
velopment of the cantaloup industry began. Several years later, green-
216 YEARBOOK, 1937
fleshed selections with salmon-tinted cavity were made from Netted
Gem or Rocky Ford and appeared as Salmon Tint and Pollock 10-25;
and deeply salmon or orange-fleshed selections appeared as Perfecto
(1919) and Superfecto (D. V. Burrell & Co., 1926). These improved
varieties of the Netted Gem type are more nearly spherical, more
heavily netted, and thicker fleshed than the parent variety, and the
present vogue is for solid salmon-colored flesh. They also differ
somewhat in adaptation to climate, culture, and handling methods.
Hale Best, introduced in 1924 by I. D. Hale, became the leading
commercial or shipping variety. It was developed by selection from
a mixed stock obtained from a Japanese gardener in the Imperial
Valley. The vines are medium in size ; fruits small, usually weighing
2 or 3 pounds each, oval to round, slightly ribbed, well covered with
dense heavy netting; flesh thick, firm-textured, solid salmon in color.
Hale Best is the earliest of the high-quality shipping melons. The
variety was quite variable when introduced, but improved forms have
been and are being developed. Hale Best No. 36 and Hale Best
No. 112 are popular strains at present. Since the variety is susceptible
to mildew, it is certain to be displaced, at least in the Imperial Valley,
by the new mildew-resistant varieties.
Hale Best is similar to Perfecto but is usually a few days earlier.
The fruit is somewhat larger and the flesh possibly firmer, and it tends
to hold up in shipment longer than Perfecto. Superfecto and Per-
fected Perfecto (Garwood & Woodside, 1925) are improved strains
of Perfecto.
It is rather striking to note how the old Acme type and its elongate,
green-fleshed descendants have tended to dominate the field in the
Middle Atlantic States while the Netted Gem and its nearly round,
salmon-fleshed deiivatives have moved West and dominated that
area from the beginning of the industry. Two other types or lines
of development, from Osage, are also of particular interest, since the
varieties that have resulted from them compete more or less with the
two types just mentioned.
The Osage was originated by Roland Morrill, an active muskmelon
breeder of Benton Harbor, Mich. It is claimed that it was selected
from a natural cross of Orange Christiana and "a small black melon
obtained from a Swedish gardener on the Osage River in Missouri",
about 1880. It was introduced by Vaughn's Seed. Store in 1887.
Some believe that Osage is a selection from Miller Cream, with which
it is now synonymous, regardless of its possible origin. Miller Cream
was developed by J. D. Miller, of Elmira, N. Y., from a supposed
cross of Sills Hybrid and Casaba. About 1890 one of Morrill's asso-
ciates discovered a single plant in a field of Osage that was believed
to be a cross between Osage and Netted Gem. Selection from this
plant ultimately produced the variety Hearts of Gold that was intro-
duced about 1895 or 1900. Morrill is said to have sent seed of cer-
tain selections from this supposed Osage X Gem cross to Paul Rose
for trial, and the latter selected and introduced the varieties Paul
Rose (also called Petosky and Osage Gem) about 1898 and Hoodo
about 1900. Both were very similar to Hearts of Gold. Hoodoo and
Hearts of Gold now are considered synonymous. It is further report-
ed that from Osage Gem D. M. Ferry & Co. selected a strain named
CUCURBITS
217
Defender, introducing it in 1901; and that Burrell Gem is a strain of
Defender, introduced by the D. V. Burrell Seed Co. in 1904. Burrell
Gem and Defender are now synonymous. In 1907 D. M. Ferry
& Co. introduced Extra Early Osage, a distinctly earlier variety of
the Osage type.
Most varieties that attained importance and later practically dis-
appeared are of unknown origin, although a few are of interest as
examples of early purposeful hybridization. Cosmopolitan, intro-
duced in 1894, was from a cross between Green-fleshed Malta and an
unnamed netted type. Christiana has been mentioned.
The probable interrelations of some of the important muskmelon
varieties are given in figure 2.
Pineapple
Netted Gem or Rocky Ford
Green-fleshed
Molto
Salmom Pollock
Tint 10-25
Perfecto
_J ,.
Christiana
Perfected Super-
Perfec+o fec+o
Mildew resistant
Indian muskmelon
"\ r
T
?Z Hybrid
Hale Best
I
Y
Osage
\ /
Y
/HaleBest Hale Best Hoodo Hearts Petosky or
i 112 36 of Gold Osage Gem
T
Mildew Resistant No.50
Defender
or
Burrell Gem
Mildew Resistant No.45
Figure 2. — Probable interrelations of some important muskmelon varieties.
Some old varieties still commonly listed are of unknown origin, but
the date of introduction is known. These include Banana (1884),
Texas Cannon Ball (1894), Hackensack (1883), Jenny Lind (1866),
Montreal (1884), Tip Top (Livingston Seed Co., 1892), Eden Gem
(1905).
Among more recent results of introduction and breeding should be
mentioned Fordhook (Emerald Gem X Jenny Lind), introduced by
W. Atlee Burpee & Co. in 1908. Honey Dew (the old French variety
White Antibes Winter) was introduced into the United States about
1900. It not only became popular, but has also often been used as a
parent in attempts to introduce its particular quality and flavor into
varieties of the cantaloup type. Honey Ball is an important hybrid
of Honey Dew and Texas Cannon Ball developed by W. H. Parker, a
Texas grower. The original cross was made in 1916 and the variety
introduced in 1924 by the Robert Nicholson Seed Co., of Dallas, Tex.
Honey Rock is said to have been produced by crossing Champlain,
Irondequoit, and Honey Dew. It was introduced about 1920 by
Watt Richardson, of Ohio.
138004°— 37 15
218
YEARBOOK, 1937
The origins of the Persian and the whiter (Honey Dew and Casaba)
types of melon are unknown. They are very old varieties and were
introduced from Europe and Asia.
The Japanese melon is a distinct new variety that lias become popu-
lar in the local markets of California. It is worthy of trial in other
sections with a long growing season. The fruits are fairly large,
round, flattened at the blossom end; the rind is tender, thin, pale
grayish green with dark blotches, sparsely netted, and very slightly
ribbed. The flesh is light salmon in color, soft, and juicy.
In the new variety, Weaver
Special, the white rind of the
Honey Ball is combined with the
salmon flesh of the shipping-type
cantaloup. It was selected from
a cross by J. C. Fluke, of C. If.
Weaver & Co., in the Imperial
Vallev, and introduced to the
trade in 1933.
Breeding for Disease
Resistance
Thirty or more years ago
growers noticed differential sus-
ceptibility of muskmelon to cer-
tain diseases. Hoodoo was men-
tioned as being resistant to blight.
In 1904 Blinn (/), of the Col-
orado Agricultural Experiment
Station, started mass selection in
the Rocky Ford variety in efforts
to obtain strains resistant to rust
(Macrosporium cucumerinum Ell.
and Ev.). Beginning in 19 06,
progenies from individual plants
and fruits were studied and sub-
jected to selection under severe
rust-infection conditions. Although selections were from open-
pollinated individuals, marked success was obtained and strains of high
commercial value were readily established. The andromonoecious
habit of the variety resulted in less cross-pollination and mixture of
strains than might be expected to occur in other varieties and species of
curcurbits. Blinn also selected for superior shipping and eating quality
and developed the first of the salmon tint strains of the Netted Gem type.
In 1925 powdery mildew (Erysiphe cichoracearitm DC.) suddenly
appeared in destructive form on melons in the Imperial Valley of
California. Fungicides were found to be inadequate in controlling the
trouble, and the crop was seriously injured for the next several seasons.
In searching for resistance, melon varieties and strains from all
parts of the world were grown by J. T. Rosa (fig. 3), of the California
Agricultural Experiment Station, and I. C. Jagger, of the United
States Department of Agriculture, in the Imperial Valley in 1920,
1927, and 1928 (12). There was no appreciable success until 1928.
Figure 3.— J. T. Rosa (1895-1928), who
made important contributions to the breed-
ing of cucurbits, particularly muskmelons
and watermelons.
CUCURBITS
219
In that year numerous plants were found in several unfixed varieties
from India that were practically free from mildew throughout the sea-
son, while other plants of the same varieties, and all plants of many
other varieties, were badly injured. Unfortunately, the fruits of all
the mildew-free plants were commercially useless because of poor
shipping and eating qualities. Several commercial varieties were
immediately crossed with the mildew-free plants. Resistance to
mildew appeared to be inherited as a simple dominant Mendelian
character. Back-crossing has considerably hastened the production
of varieties that combine the resistance of the Indian melons with
Figure 4. — Comparative test of mildew-resistant and susceptible varieties of muskmelon
in the Imperial Valley, Calif.: A, Powdery Mildew Resistant Cantaloup No. 45 is
practically mildew-free; B, Hale Best has leaves largely destroyed by the disease.
the shipping and eating qualities of the American varieties. The
development of resistant strains has now largely solved the mildew
problem in this area.
Powdery Mildew Resistant Cantaloup No. 50, distributed for com-
mercial trial in 1932, was the first fully resistant variety developed.
The fruits are quite variable in size, shape, and quality. It was pro-
duced from a cross between the Hale Best variety and one of the resist-
ant plants in the Indian varieties. Individuals from the F2, or second
hybrid generation, were backcrossed to Hale Best, and this was fol-
lowed by two additional generations of selection. Starting with No.
50, four more generations of selection finally gave Powdery Mildew
Resistant Cantaloup No. 45 (fig. 4), grown commercially for the first
time in 1936. No. 45 is quite uniform in size, shape, and quality (fig.
5). It resembles Hale Best, but matures somewhat later. The flesh
220
YEARBOOK, 193 7
has even a firmer texture than that of Hale Best. This characteristic
gives promise of making it a superior shipping melon in districts
adapted to its production.
Powdery mildew-resistant strains of Honey Dew and Honey Ball are
being developed for the Imperial Valley under the same project and
Figure 5. — Powdery Mildew Resistant Cantaloup No. 45, showing type and
uniformity of field run melons.
by similar means. Powdery Mildew Resistant Honey Dew No. 60 has
been in commercial use in this district since 1935. Outside of freedom
from mildew, it has not been quite so satisfactory from a com-
mercial viewpoint as the standard Honey Dew. Backcrossing with
Honey Dew and further selection should correct its objectionable
characters.
CUCURBITS 221
WATERMELONS
The watermelon, Citrullus vulgaris Schrad., is supposed to have been
in cultivation some thousands of years, because it had a name in
ancient Sanskrit. It is believed to be native to tropical Africa. In
1857, David Livingstone reported it as growing profusely in the
Kalahari Desert after an unusually heavy rainfall. Both edible sweet
and inedible bitter forms were present. The natives prized the sweet
ones highly and made long journeys to obtain them. In parts of
Africa the watermelon is a very important crop, furnishing not only
food but also drink during periods of drought. In parts of the Union
of Soviet Socialist Republics the fruits are important as a staple
commodity, being pickled, used as a source of sirup, and eaten fresh.
In parts of China certain firm-flcshed varieties are cut into strips,
dried, and then made into pickles, sirup, preserves, or glace sweets.
The commercial production and shipping of Avatermelons to distant
markets, to be used fresh, is much more extensive in the United States
than anywhere else in the world. Although the crop is grown for
home use and local markets in nearly every State, its culture for
shipping is confined to the Southern States and to California.
In this discussion the word "type" is occasionally used in referring
to groups of varieties of watermelons. It is admitted that the term
is loosely used, for there is do single basis for classifying American
watermelon varieties that is generally accepted as being adequate.
They might be classified according to general features of shape and
color, but that would bear no relation to use or to other qualities. A
classification according to use, whether for home and local iise or for
shipping, would denote something concerning eating quality and rind
characters, since the favorite varieties of any crop for home and local
use are those that are highest in eating quality but are often too
perishable for long-distance shipment. Within these two large classes,
however, would be found nearly the whole range of colors and shapes.
Any attempt to identify a few distinct types, all of which possess
numerous qualities in common, presents perplexing difficulties. The
problem is to establish a basis of classification in which the individual
types are neither too exclusive nor too inclusive to be of practical value.
Vabietal Improvement
A hundred years ago varieties of watermelon were ill-defined and
seedsmen's listings usually referred to types rather than to varieties in
the modern sense. With the exception of Bradford, which is still
listed by a few dealers, no variety mentioned previous to 1850 is
listed today, but a few were still common in the early 1900's. Among
these were Black Spanish, imported from Portugal in 1827; Carolina,
known in 1825; Imperial, Mountain Sprout, Seminole, and Mountain
Sweet, introduced by southern growers around 1840 to 1850, or before.
Bradford, Clarendon, Odell, Ravenscroft, and Souter all originated in
South Carolina sometime prior to 1850.
Although the leading shipping varieties of today are comparatively
recent developments, three home and local -market melons still listed
by dealers are 60 to 75 years old. Peerless or Ice Cream was intro-
duced in 1860, Phinncy Early in 1870, and Georgia Rattlesnake about
1870 by M. W. Johnson, of Atlanta, Ga.
222 YEARBOOK, 1937
As in many other vegetable crops, the period from 1880 to 1900
marked the beginning of active varietal development and introduction
by growers. A large proportion of the varieties listed at present were
introduced during that time, and many of them are unsurpassed by
later developments except in carrying better quality and disease
resistance. The originators or introducers of only a few are now
known, and the parentage of even fewer.
W. Atlee Burpee & Co. introduced Cuban Queen in 1881. Round
Light Icing appeared in 1885. Kolb Gem, originated by Reuben F.
Kolb, of Alabama, was introduced in 1885 by D. M. Ferry & Co.
Hungarian Honey apparently was introduced from Hungary about
1885 by persons now unknown. Florida Favorite, said to be a cross
between Pierson and Georgia Rattlesnake, was introduced by Girar-
deau, of Monticello, Fla., in 1887. Dark Icing was brought out by
D. M. Ferry & Co. in 1888. Gray Monarch or Long Light Icing
appeared in 1889.
Dixie was produced by George Collins, a North Carolina grower,
and introduced by Johnson & Stokes in 1890. Stories differ as to
whether Cuban Queen or the old Mountain Sweet was one of the
parents, but they agree that Kolb Gem was the other. Cole Early was
introduced by Cole's Seed Store, Pella, Iowa, in 1892. Sweetheart was
developed by a Mr. Wittenmeyer of southern Indiana about 1890 and
introduced by D. M. Ferry & Co. in 1894. One of the superior varie-
ties, in eating quality, is Kleckley Sweet, developed by W. A. Kleckley,
an Alabama watermelon grower. Its popularity and quality en-
couraged renaming, and Monte Cristo is one synonym that has
persisted. It is said to be from a cross of Boss and Arkansas Traveler
(introduced 1892). W. Atlee Burpee & Co. introduced the variety
in 1897.
The Chilean, a variety, or perhaps more accurately a type, intro-
duced from the west coast of South America, was first grown in Cali-
fornia about 1900. Both white-seeded and black-seeded strains of this
variety are now available and are extensively grown in the West.
Angeleno was introduced to the trade by Johnson & Musser, of Los
Angeles, in 1908, although it had been grown locally for some time.
Its origin is obscure, but it is believed to have been selected from a
South American stock related to Chilean. White-seeded and black-
seeded strains are available, and they possess unusually dark red in-
terior color and high quality. Another variety that gained prominence
in the West is Klondike. Its origin is unknown, but it appeared about
1900. Solid-green and striped strains are grown. These three varieties
are dominant in California at present and are hardly known elsewhere.
Conversely, the important varieties elsewhere are largely unknown in
the Pacific coast and southwest areas.
D. H. Gilbert, of Monticello, Fla., introduced Excel in 1906. The
origin of Excel is not clear, but it was evidently a poorly fixed inter-
varietal hybrid. The introducer has stated that the original stock
persisted in showing off-shape melons and, variations in seed color. A
white-seeded strain, introduced in 1926, was said to be free from these
objections.
Tom Watson, the dominant shipping melon for the last 20 years or
more, originated in Georgia and was introduced in 1906 by the
CUCURBITS 223
Alexander Seed Co . , Augusta, Ga. It is a large, long, dark-green melon,
with a thick, tough rind, that ships well. Unfortunately, however,
the quality is only medium.
The original Irish Gray is reported to have been a volunteer plant
found growing in an unoccupied stock-feeding pen by Charles Renew,
of Rebecca, Ga. , in 1 9 1 3 . Some believe the chance seed from which the
variety was increased was brought in with feed imported from South
America, but there is no proof of such an origin. In 1917 it was being
shipped in carload lots, and it was doubtless second in importance in
the early 1920's. It has yielded place, however, to Thurmond Gray,
a variety originated and introduced by a Mr. Thurmond, a water-
melon grower of Perry, Ga. Thurmond Gray first became prominent
in 1923.
Stone Mountain originated in Georgia, near Stone Mountain, and
was introduced in 1924 by the H. G. Hastings Co., of Atlanta. This
melon is round or nearly so, green, of good quality, and a fair shipper.
The vines are said to be prolific and resistant to foliage diseases.
The California Agricultural Experiment Station has effected some
substantial improvements in uniformity, flesh color, eating quality,
and shape of several varieties through the careful selection of lines
inbred for several generations. California Klondike (from Klondike)
was introduced in 1933, striped Klondike (from stock of the same name)
in 1936, and Long Mountain (from Stone Mountain) in 1936.
In 1932 the Minnesota station introduced an unusually early variety,
Northern Sweet, that extended the culture of the watermelon farther
north. It was developed by inbreeding and selection from a stock
introduced from the Union of Soviet Socialist Republics.
The Oscar H. Will Seed Co., of Bismarck, N. Dak., has introduced
two varieties designed for growing in the northern Great Plains —
Will Sugar in 1889 and Golden Anniversary in 1934. The latter
is from a cross of Wikara X Kleckley Sweet, and the other from
an unrecorded cross.
Breeding for Wilt Resistance
Until comparatively recently watermelons have been given very-
little attention by scientific workers. The work of Orton (17) is of
more than ordinary historical interest, since it is one of the first re-
corded attempts of a plant breeder to synthesize a commercial variety
resistant to a particular disease. Orton crossed the nonedible wilt-resist-
ant citron melon with the edible wilt-susceptible watermelon variety
Eden. From a large second-generation hybrid population, selections
were made of plants with potentially desirable characters. By
further selection a wilt-resistant edible variety, Conqueror, was
produced in 1911. This variety never became a popular commercial
type on account of unsatisfactory market and eating qualities.
Fusarium wilt is perhaps the most serious watermelon disease today,
preventing profitable culture of susceptible varieties in many localities.
Wilt-resistant strains of commercial importance have been de-
veloped by Porter and Melhus (19) at the Iowa station, by selection
from crosses of Orton's wilt-resistant variety Conqueror and certain
commercial varieties. The two varieties developed by crossing (Iowa
Belle and Iowa King) were about 65 percent resistant compared to the
224
YEARBOOK, 193',
1-percent-resistant commercial varieties. The exact origin of these
two varieties is rather uncertain, but they were selected from appar-
ently chance hybrids between Conqueror and one of the commercial
varieties. Porter and Melhus also developed Pride of Muscatine,
about 50 percent resistant, by selection of an inbred line of Kleckley
Sweet. These three varieties were introduced in 1930.
The Florida station released a new wilt-resistant watermelon in
1936, the Leesburg, developed by M. N. Walker by pure-line selection
in Kleckley Sweet grown on heavily infested soil.
Scalloped
Flat Thick
Fusiform
Short Long
Globular
Flat Thick
&Q 00
Conic
Broadly Sharply
(Turbinated) '
on
Pyriform
Short Long
Necked Cylindrical
Straight Crooked
A
a
Stem large at fruit
Cucurbita moschata
/Fleshy stem
C. maxima
Woody stem
C.pepo Turbinated
Figure 6. — Fruit shapes of varieties and stem characters of Cucurbita species.
The California station in 1936 introduced Resistant Klondike
^No. 7, a wilt-resistant sort selected from a cross of Iowa Belle X
Klondike. PUMPKINS AND SQUASHES
Pumpkins and squashes (Cucurbita pepo L., C. moschata Duchesne,
and G. maxima Duchesne) are undoubtedly of American origin.
Erwin (6) states that he has been able to identify fragments of stemsj
seeds, and fruits of C. pepo and C. moschata recovered from the cliff
dweller ruins of the southwestern United States. With the help of
archeologists, Erwin has determined that some of the material is
from the basket makers, whose civilization antedates that of the
CUCURBITS
i22.->
cliff dwellers; indeed, they were probably the oldest agricultural
people of whom we have any record on the North American continent.
Vavilov (30) believes that C. moschata originated in the Mexican-
Central American region and that C. maxima originated in the
Peruvian-Colombian-Eeuadorean area.
Pumpkin and Bquash varieties are numerous, but many are of local
importance only. The fruits of the summer squash are used in an
immature stage, while the rind is still tender. There are three im-
portant types — scallop, crookneck, and marrow or Italian. Each is
represented by a number of varieties. Winter squashes and pumpkins
arc used when fully mature, after the rind has hardened. Hubbard
is the leading type of winter squash, and Connecticut Field and
Small Sugar are the leading pumpkins.
As has been previously stated, the differentiation of pumpkins from
squashes is very uncertain, because as popularly classified there are
both pumpkins and squashes in all three cultivated species of Cucur-
bita. Castetter and Erwin (£) have proposed that all varieties
belonging to C. pepo and C. moschata be classified as pumpkins and
the varieties of C. maxima as squash. Adoption of this classification
would mean including the summer squash with the pumpkins, and
various other changes in present popular usage. To seed growers and
plant breeders the species are important, since varieties of the same
species cross very readily, while those belonging to different species
practically never cross in nature, contrary to popular belief. Figure
6 illustrates some of the principal differences among these three species
of Oucurbita, and figure 7 illustrates stem characteristics.
Figure 7. — Stem characters typical of the three species of pumpkin and squash.
A, Cucurbita pepo; note five-angled stem not expanded next to fruit. B, Cucurbita
mosehala; stem neither angled nor fleshy but much expanded at attachment to fruit.
C, Cucurbita maxima; stem neither angled nor expanded but fleshy and enlarged,
becoming rather spongy when mature.
Varietal Improvement
A study of the origin of our present varieties of pumpkin and squash
would require delving into colonial history, and in a number of cases
the trail of a variety appears to lead into the history of Indian tribes,
where it can no longer be followed.
Large Cheese and Connecticut Field pumpkins were common under
those names before the Revolutionary "War. Small Sugar is doubtless
a hundred years old. The Cushaw has been listed in catalogs for
226 YEARBOOK, 1937
nearly a hundred years and represents a distinct form, perhaps a
variety, that was being grown by the Indians in 1586.
Of the winter squashes, Acorn, a Turban form, was listed over a
hundred years ago. Boston Marrow was described by Burr in 1865
as synonymous with Autumnal Marrow. This variety has been
widely grown under one of these names in the United States and
Europe for a hundred years. John M. lyes, of Salem, Mass., dis-
covered its merits in 1831 and popularized it. He obtained the seed
from a friend in Buffalo, N. Y., who in turn is said to have obtained
it from a tribe of Indians (unnamed) that visited Buffalo periodically.
The Hubbard was introduced to the trade by J. J. H. Gregory, a
seedsman of Marblehead, Mass., about 1855. He stated that it had
been introduced in the vicinity of Marblehead some 60 years before.
The variety is thus conservatively 150 years old and probably older.
Marblehead, also introduced by Gregory, is thought to have been
imported direct from the West Indies about 1865. Winter Crook-
neck was described accurately, though not under that name, in 1686
and has been listed in seed catalogs for about a century.
The summer squash varieties are also very old. Both White Bush
Scallop and Yellow Bush Scallop were common in 1865, and Bun-
says the yellow variety had been common for over a hundred
years at that time. They were being shipped from the South to
northern markets before the Civil War. Yellow Summer Crookneck
and various forms of Vegetable Marrow2 like some grown today
have been listed in catalogs for over a century and are believed to
have been in common use much longer than that. Three additional
varieties' — Italian Vegetable Marrow (before 1850), Cocozelle (Vil-
morin, 1856), and Mammoth (1826) — were listed by seedsmen and
described at the dates indicated; but some or all of them are cer-
tainly older, if we may judge by their importance and widespread
distribution as stated or implied in the early references. A few vari-
ety names of 75 to 100 years ago have almost entirely disappeared
from our catalogs and modern literature, but very few, among them
Sweet Potato, common about 1850; Valparaiso (1827); and Yoko-
hama, introduced from Japan about 1850.
Is there anything new in squash or pumpkin? Few distinct vari-
eties have been introduced in the last 50 years that are superior, or
even equal, to the important old-timers mentioned. Pikes Peak, a
winter squash said to have originated in Iowa, was introduced in
1888. Fordhook was introduced by W. Atlee Burpee & Co. in 1889.
Des Moines or Table Queen is said to have been introduced from his
native country by a Danish farmer about 1900. It was 15 to 20 years
later that it became popular and acquired its present name. Delicious,
probably a selection from Hubbard, was introduced by Gregory in
1905. Golden Hubbard was introduced in 1896 by a Mr. Harrison of
Painesville, Ohio. It was found as a chance plant in a field of Hubbard.
Because of their adaptability to pollination by insects, pumpkin and
squash varieties and stocks are difficult to maintain free from mixture.
This characteristic also is a prolific source of variation even within
^Vegetable Marrow designates a group of summer varieties of C. pepo or summer squash characterized by
ova] or elongate, cylindrical fruits that are harvested tor use in a quite immature stage. Cocozelle and
Zucchini are common varieties of Vegetable Marrow.
CUCURBITS 227
good stocks. In recent years numerous seedsmen have taken greater
care in isolating selections made with specific objects in view. As a
result, there are now available many good strains that represent im-
provements in uniformity, earliness, quality, arid appearance overthe
old parent stocks. The State experiment stations have proved the
value of inbreeding in isolating superior, highly uniform strains, and
their work indicates the practicability of selecting, from this g roup
that has such rich potentialities, strains that will meet almost any set
of specifications desired.
Twenty-five years ago Cummings and Stone (4), at the Vermont
station, initiated their important studies of selection in open-polli-
nated and inbred lines of Hubbard squash with reference to yield,
chemical composition, and quality. The Vermont Hubbard, an in-
bred line, was introduced in 1914, along with other slightly different
strains. Some 6 years later the Vermont workers introduced Long
Storage Hubbard, an inbred strain selected specifically for superior
storage qualities. About 1921 Bushnell and others of the Minnesota
station introduced Kitchenette, an earlier, smaller type of Hubbard
produced by inbreeding and selection. In 1932 Krantz and others at
Minnesota introduced a very large inbred selection from Hubbard
under the name of New Brighton.
In 1932 Yeager and Latzke (34), of the North Dakota station, pub-
lished an account of the development of their new Buttercup squash.
This variety is of particular interest because it resulted from a breed-
ing program designed to develop a highly productive, high-quality,
highly nutritious squash, adapted to northern Great Plains conditions,
as a substitute for the sweetpotato — meaning the real sweetpotato,
not the Sweet Potato variety of squash. Inbred selections from a
chance cross of QualityXEssex Hybrid best met these specifications.
Buttercup is a small (3 to 3% pounds), yellow, neat, Turban-like
variety with flesh of an unusually high solids content (25 percent and
higher), containing about 15 percent of starch, 5 percent of sugar, and
2.5 to 3.0 percent of protein. It came from a wide cross and has
been difficult to make uniform.
Other varietal improvements have been made to meet specific mar-
ket demands. In 1936 the California station introduced Gray
Zucchini, an inbred strain of Zucchini, and the Connecticut station
introduced Connecticut Straight Neck from a Straight Neck inbred X
. Golden Summer Crookneck.
INHERITANCE IN THE CUCURBITS3
Cytologically this family has proved to be less interesting than the
vast amount of variation within the group would indicate. Further-
more, the material does not lend itself easily to cytological investiga-
tion by the ordinary methods. Although a long list of genera and
species has been investigated, there are no established cases of poly-
ploidy, fragmentation, or other gross chromosomal phenomena. Of
the cucurbits, cucumbers (Cucumis sativus) have 7 pairs of chromo-
somes, muskmelons (C. melo) have 12 pairs, watermelons (Citrullus
vulgaris) have 11 pairs, and the pumpkins and squashes (Cucurbita
pepo, C. moschata, and C. maxima) have 20 pairs (81).
" This section is written primarily for students or others professionally interested in breeding or genetics.
228 YEARBOOK, 1937
Inheritance in Cucumber
Information regarding the hereditary behavior of specific characters
in the cucumber is very meager. It has been shown that (1) spininess
is dominant over spinelessness ; (2) black spines are dominant over
white ones; and (3) the tendency toward the production of fruit
lacking viable seeds (parthenocarpic fruit) is apparently associated
with black spines, suggesting that these factors are linked.
Some recent work by Hutehins (10) has uncovered an interesting
green-flowered variation. This variant is female sterile. As a result,
the characteristic can be carried along only in the heterozygous condi-
tion. Tests with the normal yellow-flowered form indicate that this
green-flowered character is dependent on a single geue recessive to
normal yellow, the second-generation hybrid population segregating
into 3 normal yellow plants to 1 green-flowered plant.
Inheritance in Muskmelon
Since very early times melons have attracted both the professional
and the amateur plant breeder. Sagaret (22) in 1824, some 40 years
before the time of Mendel, made a series of interesting genetic studies
with melons. He was undoubtedly one of the earliest forerunners of
modern geneticists. His work very definitely shows that he had the
idea of contrasting unit characters in his crosses. However, he failed
to follow his results into the F2 generation or to analyze them mathe-
matically. From a cross of two distinctive varieties, Sagaret found
that in the Ft yellow skin was dominant over white skin, netted
epidermis over smooth epidermis, pronounced ribbing over smooth
ribbing, and acid flavor over sweet flavor.
Lumsden (16) attempted to determine the inheritance of the
following contrasting fruit characters: Yellow versus green skin color,
round versus obtuse-elliptical shape, large versus small seeds, ribbed
versus nonribbed, netted versus smooth surface, and large versus
small fruit size. He worked with commercial stocks of unknown
purity, but they were apparently heterozygous for the characters
studied, for he reported segregation into numerous gradations
together with the appearance of both parental types in the 1<Y No
definite conclusions can be drawn from his work. His own conclusions
concerning dominance of specific characters are not supported by his
data. With the possible exception of skin color, it would appear,
that all the characters he observed were determined by multiple
factors.
Rosa (21) has obtained ratios indicating monohybrid segregation
of certain characters; that is, the monoecious condition was domi-
nant over the andromonoecious condition; the tricarpellate ovary
was dominant over the five-carpellate ovary. In some earlier work,
Rosa (20) had been able to demonstrate that pollen from different
sources has little if any immediate effect on the qualitative characters
of the fruit.
As all varieties of muskmelons are notoriously cross-fertile, most of
the commercial varieties are highly heterozygous. It is possible to
isolate superior strains by selection and inbreeding. These methods
have been adopted to stabilize varieties of commercial importance.
CUCURBITS 229
A carefully planned inbreeding program at the California station,
continued in a few cases to the seventh generation with Salmon Tint,
Hale Best, Honey Dew, Honey Ball, and Casaba varieties, has clearly
demonstrated that no deleterious effects result from this amount of
inbreeding. T „,
Inheritance in watermelon
Recently a comprehensive, systematic breeding program at the
California station has produced much information that will be of
value in dealing with problems of watermelon breeding in the future.
Besides developing an effective pollination technique, Porter (18),
has studied the biology of fruit setting in relation to certain environ-
mental factors and has made observations on the effects of inbreeding.
With reference to inbreeding, strains were isolated that were
comparatively homozygous for fruit-shape factors and for a number
of fruit characteristics — for example, flesh color, texture of flesh,
solidity of fruit, etc. Most varieties show no loss of vigor after four
to five generations of inbreeding.
]n the case of watermelon wilt, the phenomena of resistance and
susceptibility are relative. The commercial varieties are as a rule
very highly susceptible to wilt; the inedible varieties (as stock citron),
on the other hand, are more or less resistant. No variety observed
to date seems to be completely immune.
Rosa (21) found that the majority of watermelon varieties are
monoecious and a few varieties are andromonoecious. Crosses of
varieties representing these two types indicated that the difference
was monogenic, the monoecious condition being dominant.
Porter and Poole, at the California station, have determined the
mode of inheritance of a number of characters in the watermelon.
All of the characters investigated gave monohybrid ratios, and there
was no evidence of linkage among any of them. Their experiments
indicate that (1) in flesh color, red is dominant over yellow; (2) in
seed-coat color, black is dominant over white and tan; (3) in fruit-
skin color, dark green is dominant over striped and white; (4) in rind,
toughness is dominant over tenderness; and (5) in fruit shape, short
is dominant over long.
Inheritance in Pumpkin and Squash
The question of whether pumpkins and squashes will cross has
always interested amateur gardeners. Considerable confusion has
arisen from an imperfect understanding of botanical relationships.
There is no accepted basis for distinguishing pumpkins from squashes.
Botanically they belong to three species of the genus Cucurbita. As
popularly classified there are both pumpkins and squashes in all three
species.
Castetter and Erwin (2) and Erwin and Haber (7) have shown that
varieties belonging to the same species cross very readily, while those
belonging to different species practically never cross in nature. How-
ever, cross-pollinating certain varieties belonging to Cucurbita pepo
with varieties of C. moschata has produced partially fertile hybrids.
Until recently only sterile hybrids, or complete failure to develop
fruits, had resulted from cross-pollinating varieties of C. maxima with
varieties of C. jwpo and C. moschata. Van Eseltine, at the New York
230
YEARBOOK, 1937
(State) station, has recently obtained fertile hybrids of reciprocal
crosses of C. pepo and C. moschata and of C. maxima and 0. moschata.
Dana, of the Bureau of Plant Industry, in working for curly top
resistance in squash varieties, obtained hybrids of C. moschata and
C. maxima that were self-fertile in the Ft but male-sterile in the F2.
He has backcrossed the hybrid to both parents and obtained fertile
b'ackcross progenies.
Early attempts at a genetic analysis of this genus have proved to
be practically worthless, chiefly because the investigators were using
heterozygous material in their experiments. They underestimated
the value of establishing pure lines as a primary factor in securing
reliable results in genetic experiments.
The first attempt at a careful genetical analysis of Cucurbita was
made by Sinnott and Durham (26). They used several varieties of
C. pepo. After being inbred for several generations, the original types
were evidently homozygous, as evidenced by their behavior. At this
point, using the inbred material, an investigation of the inheritance
of certain characters was initiated. From their results the several
characters studied appear to be inherited, as indicated in table ] .
Table ].
-Inheritance in summer squash fruits, Cucurbita pepo
(after Sinnott and Durham)
Contrasting characters
Behavior in Fi
Segrcgat ion in Fa
Exterior "ground" color:
White
3 white to 1 yellow (cortain crosses produce (.5:1).
Whites, green
Exterior striping:
White fruits, nonstriped r. green-
striped.
Yellow fruits nonstriped r. white-
striped.
Flesh color:
White— -
12 white to 3 yellow to 1 green.
43 white and 0 green-striped.
Complex.
do _..
White-striped ..
White..
Surface:
do
Shape:
Disk..
!) disk to 6 sphere to 1 long. ] liferent crosses gave
different results. Maybe 1, 2, or more factors
involved. In some, tho situation is very com-
plex.
Sinnott and his coworkers (27, 28) have greatly extended this
analysis, particularly with regard to the genes governing sizes and
shapes in fruits. In general, these characters appear to be determined
by numerous factors, so their inheritance is complex and not com-
pletely clear. It has been shown that in the cucurbits inbreeding up
to at least 7 to 10 generations does not result in a general decline in
the vigor of the plants. This behavior is in distinct contrast to that
of corn, onions, etc., where inbreeding immediately brings about a
decline in vigor.
Hutchins (11), at the Minnesota station, has shown in different
color types of Hubbard squash (Cucurbita maxima) that green is
partially dominant to blue. The Fi was intermediate in color, and
the F2 and backcross populations segregated as for a single factor.
Lotsy (IS) showed that in C. maxima exterior fruit-color inheritance
CUCURBITS 231
is for the most part complex. In a cross of Turban (a red strain) X
Green Hubbard, the F2 segregated into 3 reddish to 1 green. The
dominance of the red was incomplete. In a cross of Turban X Silver
Gray, a very wide assortment of colors occurred in the F2. Lotsy also
showed that the Turban character (fig. 2), caused by incomplete
enclosure of ovarian tissue by receptacle or torus tissue, is due to two
dominant genes. Turban X Green Hubbard gave an F3 segregation
of 15 Turban forms to 1 non-Turban form.
LITERATURE CITED
Buns, P. K.
1908. cantaloupe brbeding. Colo. Agr. Expt. Sta. Bull. 126, 10 pp.,
illus.
Castetter, E. P., and Erwin, A. T.
1927. A SYSTEMATIC STUDY OP SQUASHES AND PUMPKINS. Iowa Agr. Expt.
Sta. Bull. 244, pp. [107]-135, illus.
Cummings, M. B., and Jenkins, E. W.
1928. PURE LINE STUDIES WITH TEN GENERATIONS OF HUBBARD SQUASH.
Vt. Agr. Expt. Sta. Bull. 280, 29 pp., illus.
— and Stone, W. C.
1921. YIELD AND QUALITY IN HUBBARD SQUASH. Vt. Agr. Expt. Sta.
Bull. 222, 4.8 pp., illus.
Edmond, J. B.
1931. SEASONAL VARIATION IN SEX EXPRESSION OF CERTAIN CUCUMBER
varieties. Amor. Soc. Hort. Sci. Proc. (1930) 27: 329-332.
Erwin, A. T.
1931. nativity of the cucurbits. Bot. Gaz. 91: 105-108, illus.
and Haber, E. S.
1929. species and varietal crosses in cuourbits. Iowa Agr. Expt.
Sta. Bull. 263, pp. [343J-372, illus.
Haber, E. S.
1929. inbreeding the table queen (des moines) squash. Amer.
Soc. Hort. Sci. Proc. (1928) 25: 111-114.
HlBBARD, A. D.
1934. metaxenia in the apple and squash. Amer. Soc. Hort. Sci. Proc.
(1933) 30: 140-142.
Hutchins, A. E.
1936. the inheritance of a green flowered variation in cucumis
sativus. Amer. Soc. Hort. Sci. Proc. (1935) 33: 513.
1936. THE INTERACTION OF BLUE AND GREEN COLOR FACTORS IN HUBBARD
squash. Amer. Soc. Hort. Sci. Proc. (1935), 33: 514.
Jagger, I. C, and Scott, G. W.
1932. cantaloupes. 6th Internatl. Cong. Genetics Proc. v. 2, p. 359.
Jones, H. A., and Rosa, J. T.
1928. truck crop plants. 538 pp., illus. New York.
Lloyd, J. W.
1935. muskmelon. In Bailey, L. H., The Standard Cyclopedia of
Horticulture, v. 2, pp. 2027-2031, illus. New York.
Lotsy, J. P.
1920. CUCURB1TA-STRIDJVRAGEN. II. EIGEN ONDERZOEKINGEN. Geiieti-
ca 2: J-21, illus.
LUMSDEN, D.
1914. mendelism in melons. N. H. Agr. Expt. Sta. Bull. 172, 58 pp.,
illus.
Orton, W. A.
1911. THE DEVELOPMENT OF DISEASE-RESISTANT VARIETIES OF PLANTS.
4th Conf. Internatl. Genetique, Paris, pp. 247-265.
232 YEARBOOK, 193 7
(18) Porter, D. R.
1933. watermelon breeding. Hilgardia. 7: 585-624, illus.
(19) and Melhus, I. E.
1932. THE PATHOGENICITY OF FUSARIUM NIVEUM (EFS.) AND THE DEVELOP-
MENT OF WILT-RESISTANT STRAINS OF CITRULLUS VULGARIS
(schrad.) Iowa Agr. Expt. Sta. Research Hull. 149, pp. [123]-
184a, illus.
(20) Rosa, J. T.
1927. DIRECT EFFECTS OF POLLEN ON FRUIT AND SEEDS OF MELONS.
Amer. Soc. Hort, Sci. Proe. (1 920) 23: 243-248.
(21) ■ —
1928. THE INHERITANCE OF FLOWER TYPE IN CUCUMIS AND CITRULLUS.
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(22) Sagaret, M.
1826. CONSIDERATIONS SUH LA PRODUCTION DES HYBRIDS DES VARIANTKS
ET DES VARIANTES EN GENERAL, ET SLR CELLES DE LA FAMILLE
DES CUCURBITACEES EN PARTICULIER. Ann. Sei. Nat., Bot.
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(23) Scott, G. W.
1933. INBREEDING STUDIES WITH CUCUMIS MELO. Amer. Sof. Hort.
Sci. Proc. (1932) 29: 485.
(24)
1934. SEX RATIOS AND FRUIT PRODUCTION STUDIES IN RUSH PUMPKINS-
Amer. Soc. Hort. Sci. Proe. (1933) 30: 520-525.
(25)
1935. OBSERVATIONS ON SOME INBRED LINES OF HUSH TYPES OF CVC\.:R-
bita pepo. Amer. Soc. Hort. Sci. Proc. (1934) 32: 480.
(26) Sinnott, E. W., and Durham, G. B.
1922. inheritance in the summer squash. Jour. Heredity 13: 177-
186, illus.
(27) and Durham, G. B.
1927. A FACTORIAL ANALYSIS OF CERTAIN SHAPE CHARACTERS IN SQUISH
fruits. Amer. Nat. 61: 333-344.
(28) and Hammond, D.
1930. factorial balance in the determination of fuuit shape in
cucurbita. Amer. Nat. 64: 509-524, illus.
(29) Tiedjens, V. A.
1928. SEX ratios in cucumber flowers as affected by different
conditions of soil and light. Jour. Agr. Research 36: 721-
746, illus.
(30) Vavilov, N. I.
1935. [botanical-geographical principles of selection.] 60 pp.
Moskva and Leningrad. [Translation in U. S. Dent. Aer..
Bur. Plant Indus.]
(31) Whitaker, T. W. .
1930. chromosome numbers in cultivated cucurbits. Amer. Jour
Bot, 17: 1033-1040, illus.
(32)
1931. SEX RATIO AND SEX EXPRESSION IN THE CULTIVATED CUCURBITS.
Amer. Jour. Bot, 18: 359-366.
(33)
1933. CYTOLOGICAL AND PIIYLOGENETIC STUDIES IN THE CUCURBITACEAE
Bot, Gaz. 94: 780-790, illus.
(34) Yeager, A. P., and Latzke, E.
1932. BUTTERCUP SQUASH, ITS ORIGIN AND USE. N. Dak. Agr. Expt
Sta. Bull. 258, 19 pp., illus.
ONION IMPROVEMENT
II. A. JONES, Principal Olericulturisl,
Division of Fruit and Vegetable Crops
and Diseases, Bureau of PianL Industry
J. HE onion is used as a food and for seasoning in nearly all countries,
and its culture no doubt dates back to very remote antiquity. Ac-
cording to Sturtevant, as reported by Hedrick (9),1 it is —
One of the things for which the Israelites longed in the wilderness and complained
about to Moses. * * * Onions were prohibited to the Egyptian priests, who
abstained from most kinds of pulse, but they were not excluded from the altars of
the gods. * * * They were introduced at private as well as public festivals
and brought to the table. The onions of Egypt wore mild and of an excellent
flavor and were eaten raw as well as cooked by persons of all classes.
ORIGIN, CULTURE, AND USES
Bailey (2) describes eight species of onions cultivated in North
America. Allium neopolitanum Cyr. and A. moly L. are grown as
ornamentals. Garlic (A. sativum L.) is used mainly for seasoning.
The leek (A. porrum L.), the Welsh or Japanese onion (A. fistulosum
L.), and the shallot (A. ascalonicum L.) are all used in the green
condition. The tops of chives (A. schoenoprasum L.) are used for
seasoning. A. cepa L. is the species cultivated most extensively.
Bailey divides this species into several botanical varieties as follows:
(1) The extensively cultivated bulbing type of onion propagated by
seed; (2) the potato or multiplier onion, which propagates by branch-
ing at the base; and (3) the top onion, which forms bulbils in the
inflorescence, which are often used for propagation.
Vavilov (21) names the middle-Asiatic center, comprising north-
western India, all of Afghanistan, the Soviet Republics of Tajik and
Uzbek, and western Tien Shan, as the primary place of origin of the
commonly cultivated onion, Allium cepa. As secondary centers of
origin of this species he lists (1) the Near East, which includes inner
Asia Minor, the whole of Transcaucasia, Persia (Iran), and the alpine
Turkmen Republic, and (2) the Mediterranean region. For the Jap-
anese onion, A. fistulosum, which is cultivated extensively in the
Orient, Vavilov gives the primary place of origin as the Chinese center,
which comprises alpine central and western China and the adjacent
lowlands.
From these centers of origin the onion has spread to all countries
where the crop can be grown at some season of the year. Just when
the cultivated onion was first introduced into North America is not
known, but at present it is cultivated everywhere in this country as a
1 Italic numbers in parentheses refer to Literature Cited, p. 24i).
233
188904°— 87 10
234 YEARBOOK, 1937
home-garden and market-garden crop. Extensive commercial pro-
duction, however, is confined to special regions.
The early crop for shipment is grown chiefly in Texas, California,
and Louisiana from transplanted plants set in the field in late fall and
early winter and harvested the following April, May, and early June.
The predominant variety is Yellow Bermuda, but Crystal White
Wax and Creole are also grown to a considerable extent. These
varieties are used for the early crop because they produce bulbs during
the time of the year when the days are short. The Bermuda type
cannot be stored successfully for more than a few weeks, but Creole
is a good storage onion.
The intermediate crop is grown primarily in Texas, New Jersey,
California, Oklahoma, Washington, and Iowa from transplanted
seedlings and from dry sets, the crop being harvested chiefly during
June and July. In Texas the principal intermediate variety is the
Yellow Bermuda; in California, the Stockton Yellow Globe and
California Early Ked; in Iowa, the Yellow Bottleneck; in the East,
the Ebenezer, Yellow Strasburg, and others of the same type. In
Texas and California the intermediate crop is grown from transplants;
in other districts dry sets are used.
The late or main crop, which is produced chiefly in Michigan,
New York, Indiana, California, Ohio, Massachusetts, Colorado,
Minnesota, Idaho, Oregon, Washington, Wisconsin, and Utah, is
usually seeded directly in the field and harvested in August and
September. This crop, most of which is stored, supplies the demand
from September until late March or April. Storage varieties arc not
OFTEN an onion crop that might have been a profitable one brings
the grower a loss because of unfavorable weather conditions and the
occurrence of certain insect pests and diseases that take their toll in
both field and storage. Smut occurs in practically all of the main
onion-growing States of the North, while pink root is present in
most of the onion districts of the South and West. Onion thrips
are always present on both the bulb and seed crop. Smudge, neck
rot, and other diseases take an additional share of the crop after
harvest. Other losses occur because of premature seeding in the
field and sprouting in storage. Until very recently, little has been
done to alleviate these difficulties by scientific breeding methods.
Present researches and experiments, however, make the possibility
of preventing many such losses by developing superior varieties of
onions more and more promising. In most cases resistant varieties
and strains have been found, and in some cases promising hybrids
have been produced and are under test.
ONIONS 235
the same for all sections. In California, Australian Brown is used;
in Oregon, the Oregon Danvers; in the Rocky Mountain States,
Sweet Spanish and Mountain Danvers, and in the Northern States
from Minnesota to Massachusetts, the yellow globe type such as
Yellow Globe Danvers, Southport Yellow Globe, and Ohio Yellow
Globe. Other varieties stored to some extent are Southport Red
Globe, Southport White Globe, Red Wcthersficld, White Portugal,
Ebenezer, and Yellow Strasburg. With the exception of Sweet
Spanish, these storage varieties are rather pungent.
During seasons of low production imports have been chiefly from
Spain, Egypt, Chile, Italy, and Canada.
The quantity of onions consumed per capita in the United States is
fairly constant regardless of price. During years of overproduction
a portion of the crop is usually plowed under, and during years of
underproduction imports are increased. The onion market is not very
elastic, oversupplies are not readily absorbed, and consequently it is
rather easy to have overproduction. As a rule, onions are used by
most families in comparatively small quantities but fairly constantly
throughout the year for seasoning, in salads, and as a main dish cooked
in a variety of ways. Onion salt is also being manufactured in con-
siderable quantities for use in catsup, chili sauce, soups, and sausage.
But while the quantity of onions consumed per capita is not large,
the total amount used gives this crop a commercially important place
among the vegetables. The average onion acreage for the United
States during the 5-year period 1928-32 was 84,430 acres, with a
production of 13,247,000 100-pound sacks, giving a yearly return to
the producers of approximately $17,353,000.
VARIETAL ADAPTATION
Among the onion varieties grown in the United States there are many
types differing in size, shape, and color of bulbs, pungency, keeping
quality, time of maturity, and tolerance to diseases, insects, sunscald,
and high and low temperature. It has been necessary to maintain
a considerable number of varieties, partly because of consumer
demands relating to season and use, but chiefly because of the different
environmental conditions under which the crop is grown. The storage
onions of the North, for example, do poorly in the South, and the
extra early varieties commonly grown in the South are ill-suited for
production in the North.
The adaptability of varieties to certain regions, according to
Magruder and Allard (14), is often determined by length of daylight,
called the photoperiod. The time when bulbing is initiated is deter-
mined by the length of the photoperiod and not by the age of the plant,
and the minimum photoperiod necessary to initiate bulbing vaiies
with different varieties. The investigators named above were able
to group the varieties into classes according to the minimum photo-
period required to produce 100 percent normal bulbs as follows:
12 hours, Yellow Bermuda, White Creole, and Early Grano; 13 hours,
California Early Red, Yellow Strasburg, Ebenezer, and Yellow Dan-
vers Flat; 13.5 hours, Early Yellow Globe, Mountain Danvers, Ohio
Yellow Globe, Australian Brown, White Portugal, Southport Yellow
Globe, and Sweet Spanish strain no. 1; 14 hours, Red Wethersfield,
236 YEARBOOK, 1937
Soutliport Red Globe, and Italian Bed; 14.25 hours, Yellow Globe
Danvers; normal day (maximum of 14.9 hours), Sweet Spanish strain
no. 2. Most commercial varieties are not homozygous or pure for
the genes that determine the minimum photoperiod for bulbing, so
there may be some plants tbat bulb at a shorter photoperiod than is
characteristic for the variety.
Early maturity, according to Magruder and Allard, seems to depend
on the ability of the plant to start bulb formation at short photo-
periods and to proceed very rapidly with the process after the minimum
period for bulbing is reached. In the North it is almost impossible to
secure good yields of the extra early varieties like the Bermudas,
Early Grano, and Creole by sowing seed directly in the field, because
seeding is usually done at a date when the length of day has already
passed the minimum for bulbing. Consequently the plant develops
only a few leaves and a small bulb. To secure large bulbs of the extra
early varieties in the North it is necessary to sow seed early in a
greenhouse or in a hotbed in order to have large plants before the
minimal photoperiod for bulbing occurs.
The late-maturing varieties of onions usually do poorly in the South,
chiefly because the photoperiod required for bulbing comes during hot
weather, when sunscald, thrips, and pink root combine to retard the
growth of the plant. Lateness of maturity, according to Magruder and
Allard, may bo due to a long photoperiod requirement, to a slow rate of
bulb development after the minimum occurs, or to a combination of the
two. Sweet Spanish, a late variety, is able to produce fair crops in the
South because it is somewhat resistant to sunscald, thrips, and pink root.
In central California there is a considerable acreage of the so-called
intermediate crop of onions. The seed is usually sown in field beds in
late August and the seedlings are transplanted in late November and
December. During the winter and early spring the plants usually
make a large vegetative development. Bulbing does not begin in
the spring until the hours of daylight reach the minimum for the
varieties in question. For this crop, varieties such as Stockton
Yellow Globe, California Early Red, and Italian Red are used. If
the late varieties of the North or the early varieties of the South are
used they make a good vegetative growth, but in the spring the
plants form seed stems instead of bulbs.
These few points regarding adaptation are brought out to show why
a variety may do well in one district and be worthless in another.
Sweet Spanish is much more widely adapted than many varieties
because of its resistance to high temperature conditions and to certain
insects and diseases. Other varieties will be more widely adapted
when plant breeders incorporate in them genes for resistance to
diseases and insects and others that permit them to grow under a wider
range of climatic conditions.
INTRODUCTION OF PRESENT COMMERCIAL VARIETIES
It is difficult to obtain authoritative information on the method and
time of introduction of the older important commercial varieties,
the first mention in seed catalogs of certain important varieties is as
follows: Silverskin (White Portugal), 1810; Crystal Wax, 1901;
Red Wethersfield, 1849; Ohio Yellow Globe, 1901; Soutliport Red
ONIONS 237
Globe, 1889; Southport White Globe, 1889; Southport Yellow Globe,
1888; Yellow Danvers (Flat), 1866; and Yellow Strasburg, 1844.
According to Morse (17), the variety Australian Brown was intro-
duced into North America from Australia, in 1894, under the name of
Brown Spanish, but later was renamed by W. Atlee Burpee. An
improved strain, Australian Brown U. C. No. 1, was introduced by
the California Agricultural Experiment Station in 1935. Sweet
Spanish seed was secured by the United States Department of Agri-
culture from Luis Tono, American consul in Spain, in December 1908,
under the name of Denia, and was distributed to seedsmen and
several agricultural experiment stations. An improved strain, Sweet
Spanish Colorado State No. 6, was introduced by the Colorado
Agricultural Experiment Station in 1936. According to Morse (17),
Prizetaker was first offered to the trade in America by William Henry
Maule in 1888, from seed grown by C. C. Morse the preceding year at
Santa Clara, Calif. In Europe this variety was known as Spanish
King. The Early Grano onion, named and introduced by the New
Mexico Agricultural Experiment Station (8), was secured from Spain
in 1925 under the name of Valencia Grano by the Barteldes Seed Co.,
of Lawrence, Kans.
Morse (17) states that the California Early Keel has been developed
from the Red Italian Tripoli. The latter was probably brought to
California by the early Italian emigrants before 1900. An improved
strain, California Early Red, U. C. No. 1, was introduced by the
California Agricultural Experiment Station in 1935. The variety
Stockton Yellow Globe was originated by a number of American and
Japanese growers in California in response to a demand for a non-
bolting yellow globe onion; consequently there are a number of strains
of this variety, the type of which has not as yet become definitely
established. According to Erwin and Harter (6), the parent stock of
Yellow Bottleneck was "Birn Zwiebel" and was secured from Germany
in the late sixties by a Mr. Laf renz, of Davenport, Iowa. The Creole
variety was probably brought to Louisiana by the early French
settlers. Yellow Bermuda (formerly called White Berrmida) was
probably introduced from the Canary Islands some time prior to 1901.
VARIETAL IMPROVEMENT
Often an onion crop that might have been a profitable one brings the
grower a loss because of unfavorable weather conditions and the
occurrence of certain insect pests and diseases that take their toll in
both field and storage. Smut occurs in practically all of the main
onion-growing States of the North, while pink root is present in most
of the onion districts of the South' and West. Onion thrips are always
present on both the bulb and seed crop. Smudge, neck rot, and other
diseases take an additional share of the crop after harvest. Besides
these, other losses occur because of premature seeding in the field and.
sprouting in storage. Little has been done until very recently to
alleviate these troubles by scientific breeding methods. Hope of
preventing many losses in the future by developing varieties resistant
to various insects and diseases and certain unfavorable climatic con-
ditions seems more and more promising. Some of the work actually
under way is described in later sections of this article.
238 YEARBOOK, 1937
Commercially Maintained Seed Stocks
To give a comprehensive idea of onion improvement as it is being
conducted at present, it will be necessary to review methods employed
by commercial interests as well as by State and Federal investigators.
Most of the onion seed produced at the present time is grown in Cali-
fornia. There the mother bulbs of the different varieties are grown
like those for market, with the exception that the rate of planting is
heavier so that the plants are more crowded and a somewhat smaller
bulb is produced. These are grown by contract at so much per 100-
pound bag. Harvesting is usu ally done in August and Sep tember, and
the bulbs remain in the bag until time to plant in the field in late No-
vember or December. Before planting, most seedsmen pass the mother
bulbs over a grading table to sort out the off-color ones and at the
same time select mother bulbs of good type to plant for the production
of stock seed. As a rule, the bulbs of the various varieties are distrib-
uted to ranchers who contract to grow the seed at so much per pound.
If mother bulbs are selected carefully, it is possible to maintain
fairly uniform stocks of the different varieties. Onions, however, are
highly cross-pollinated, and commercial varieties have a very mixed
heredity. Usually there are enough differences between the plants of
a variety so that it is possible to select rather widely for type. It is
seldom that any two people have exactly the same idea of what the
type should be in making selections. As a consequence there are many
strains of each variety. Also, by following the selection method exclu-
sively certain recessive colors and off- types are never bred out; they
are carried along indefinitely. Progressive seedsmen, however, are
beginning to use scientific methods to develop strains that are more
uniform in size, shape, and color. Breeding for the development of
resistance to diseases and insects, however, is being conducted chiefly
by the Federal Government and by the State-supported research
institutions. To understand these methods better it is well to know
something about the flowering habit and the floral characters of the
onion p an . Inflorescence and Pollination
■When mother bulbs are planted in the late fall or winter the ru-
dimentary parts of the flower stalks do not differentiate until the fol-
lowing spring, and it is usually 3 or 4 weeks after differentiation before
the flower parts emerge through the sheaths that surround them. The
flower stem elongates rapidly and may develop to a height of 5 or 6
feet but usually not more than 3 or 4 feet. The number of flower
stems per plant ranges from 1 to 20 or more, depending on the size
of mother bulb, the variety, and climatic conditions.
The flowers are borne in simple umbels at the upper end of the
elongated stalk, the young buds being enclosed within a papery bract
which is split open by pressure of the developing buds shortly before
the flowers open. The number of flowers per umbel may range from
50 or less to 2,000 or more. The flowers have six perianth lobes or
floral leaves in two whorls of three each and six stamens in two whorls
of three each. The pistil has a three-celled ovary with two ovules in
each cell. The anthers of the three inner stamens are the first to
open, shedding their pollen one after the other at irregular intervals,
ONIONS
239
Tnner whorl of sfamens
after which the anthers of the outer whorl of stamens open, also at
irregular intervals (fig. 1). The pollen of a single flower is shed
before the stigma becomes receptive, and the process is usually com-
pleted in 24 to 36 hours. The style is approximately 1 mm (0.039
inch) long when the flower first opens, not reaching its maximum
length of about 5 mm (0.197 inch) until a day or two after all the
pollen from that flower has been shed. The flowers of a single head
may continue to open
over a period of 2
weeks or longer, and
a plant may be in
flower for 30 days or
more.
Most of the pollen
is shed between 9 a.
m. and 5 p. m. Pol-
lination is effected
mainly by insects
that go from flower
to flower and visit the
nectaries at the base
of the three inner
stamens. Interpolli-
nation among flowers
of the same umbel is
no doubt of frequent
occurrence, as the
same insect has been
observed to visit
many flowers on an
umbel before leaving.
In the onion, how-
ever, cross-pollina-
tion is the rule.
Outer whorl ofshmms
Inrier wborlof$tamens(<iehisced)
Selfing an Aid in
Onion Breeding
In the onion selfing
or inbreeding, accom-
plished when a plant
is self -pollinated, is
Figure 1. — Method of flower opening and pollen shedding
in the onion: A, Flower bud just before opening; B, the
two outer whorls of floral organs expanding and the
inner whorl of stamens elongating; C, just before the
shedding of the pollen by the inner whorl of stamens;
note the short style; D, the three stamens of the inner
whorl have shed their pollen and the three of the outer
whorl have elongated; E, all six stamens have shed their
pollen; note the long style, now receptive. (From Jones
and Rosa, Truck Crop Plants.)
not an end in itself
but merely one of the tools used in the breeding program. Inbreeding
in the onion is almost always accompanied by a loss of vigor for a num-
ber of generations. However, it permits many undesirable characters
that have been carried along in the germ plasm, perhaps covered up
by dominant traits, to express themselves, so that the lines possessing
them can be rogued out. The main purpose of inbreeding is to
develop lines that will breed true for certain characters. Selfing is
accomplished in the onion by covering the entire umbel to prevent
contamination with foreign pollen. When the first flower opens on an
umbel the entire inflorescence is enclosed within a 1-pound manila
240
YEARBOOK, 1937
paper bag and tied closely so that there will be a crowding of the flowers
within the bag (fig. 2). If the umbels are small, as is usually the case
after several generations of inbreeding, a number of heads can be
enclosed in the same bag, thereby crowding flowers and facilitating pol-
lination. Once each day toward evening, when the pollen is dry, the
bags are tapped rather vigorously to help circulate the pollen within.
Breeding Program with Inbred Lines
Much of the improvement work, especially by commercial seedsmen,
has as its object the freeing of varieties from plants that are off-type
and making a variety or strain uniform for important commercial
Figure 2. — Method of self-pollinaling onions. Inflorescences are enclosed
in J -pound manila paper bags.
characters. This can best be done by selecting bulbs that are true
to type, selfing to secure uniform and true breeding lines, and finally
massing the apparently similar selected inbred lines to bring about
crossing, which will restore vigor. Such a program follows:
First year. — Select a large number of commercial bulbs that approach the ideal
for the variety; the larger the number the better the chance of securing desirable
lines. Plant the selected mother bulbs in late fall, winter, or early spring, depend-
ing upon the locality.
Second year. — Self-pollinate as described in the section on selfing.
Third year. — Grow progenies of all selfed plants separately. Destroy unde-
sirable lines during the growing season, or at harvest time, or upon their removal
from storage. Retain the best bulbs in 25 or more of the most outstanding lines
and plant for selfing and open-pollination.
Fourth year. — Half of the umbels on each plant are selfed and the others are
allowed to open-pollinate. By following this procedure it is possible to secure a
ONIONS
211
supply of open-pollinated seed of superior quality that can be increased rapidly
to quantity production. For practical purposes it is usually best not to inbreed
more than two generations, because as a rule the plant is greatly weakened and
it is difficult to secure a quantity of seed.
Fifth year. — Grow the progenies that were selfed in the fourth year separately
and again select the best bulbs from at least 25 lines for open-pollination.
Sixth year. — Group all selections and plant them in the field so that the maxi-
mum amount of crossing between unrelated lines will occur. Mass the seed and
increase.
Use of Flies to Facilitate Crossing
When new characters are to be incorporated in a variety, as is
necessary in most cases when breeding for disease resistance, then the
breeder must resort to crossing. Plants to be used for crossing are
figure 3. — Method of introducing flies into small pollination cages. The cages are
made of cheesecloth stretched over wire frames and tied at both ends.
(Courtesy California Agricultural Experiment Station.)
usually set 2 to 3 feet apart in the row to allow plenty of room for
manipulation of the small cage to be described later. The umbels are
bagged as soon as the first flower opens. At first only a few flowers
on an umbel open daily, but the number increases until full bloom,
when 50 or more may open in a single day. These early flowers are
removed several times daily from the umbel of the female parent.
When the weather is hot they must be removed often because the
anthers shed their pollen very soon after a flower opens. When
blossoming is at its peak, open flowers are no longer removed but are
emasculated and used for crossing. Umbels must be examined fre-
quently and the anthers removed from the open flowers before the
pollen is shed to prevent contamination of the umbel.
242 YEARBOOK, 1937
When enough flowers have been emasculated, the remaining buds
of the inflorescence are removed. The emasculated and disbudded
umbel is then enclosed under a small cheesecloth cage as shown in
figure 3. The inflorescence of the male, or pollen, parent, which has
also been kept covered to prevent pollen contamination, is cut off and
enclosed within the same cage, with the base of the stalk standing in a
bottle of water, When handled in this manner the flowers continue to
open and shed pollen for a week or more. Flies are added to the cage
to do the pollinating. This technique, as compared with hand-pollina-
tion, makes it possible to multiply greatly the number of crosses, and
also to secure a higher percentage of seed setting. To be certain that
flies are free from foreign pollen, it is necessary to raise them under
controlled conditions.
At Davis, Calif., where considerable onion -breeding work is under
way, a technique for the growing of flies for pollination purposes has
been developed. Lungs of beef, upon which the adult blowflies lay
their eggs, are exposed on tables in the open. The lungs are under a
roof to provide protection from a high temperature and rain, which
might kill many of the larvae. Within a few days the larvae hatch
and begin to feed. When mature they begin to wander about to find a
place to pupate, at which time they are trapped by attaching a
trough along the side of the table into which the larvae fall. A pail,
containing a small amount of finely screened sand, is suspended at the
end of the trough. Once each day the pail is removed and replaced
by another so that each pail will contain larvae of approximately the
same age. The larvae soon burrow into the sand to pupate, and later
the pupae are separated from the sand by screening. The pupae are
held at room temperature and are placed in a small screen cage before
the adults emerge (fig. 3). Each cage, measuring about 6 by 6 inches,
has a cone-shaped top, at the apex of which is a small opening closed
by a cork. As the flies hatch they gradually move up into the cone.
When used in pollinating, the cone is inserted into the lower end of
the cloth cage containing the two umbels, the cork is removed, and as
many flies as needed are allowed to escape into the cage. They soon
begin to feed and in doing this carry pollen from flower to flower and
accomplish pollination.
It is often desirable to accumulate mature pupae in order to have a
good supply on hand for the peak of the pollinating season. They
can be kept for several weeks at about 45° F. It is best not to store
them at this temperature until the adults are almost ready to emerge,
otherwise fewer of them will emerge. Also, the flies appear to be less
active when the pupae are stored early in the pupation period.
BREEDING FOR RESISTANCE TO DISEASE
Pink, root of onion, caused by the fungus Phoma terrestris Hansen, is
a major disease in many onion-growing districts, especially of the South
and West. Porter and Jones (18), working in California, found that
Sweet Spanish was slightly resistant to pink root and that the Japanese
onion, Allium fistulosum, Nebuka type, was very resistant. In
California, Australian Brown No. 17, a single plant selection, is
somewhat more resistant than the commercial variety from which
it was isolated, and Sweet Spanish No. 35, another single plant
ONIONS 243
selection, is also more resistant than the commercial variety. Felix (7)
has also reported that Winterhecke and White Welsh, varieties of
A. Jistulosum, as well as different strains of Nebuka (Natsu-negi
Nobiika, Senj-negi Nebuka, Tokyo-Nebuka, and Iwatsuki), are re-
sistant to pink root.
The various types _ of Allium Jistulosum have little commercial
importance in the United States, but it would bo desirable to have
certain insect- and disease-resistant characters they possess incorpor-
ated in varieties of A. cepa. With these objects in view, Emswel-
ler and Jones (S) have made a largo number of crosses between some
of the Nebuka types and many varieties of A. cepa. First-generation
hybrids of Yellow Globe Dan vers X Nebuka and Nebuka X Austra-
lian Brown have been grown on soil heavily infested with the pink
root organism; the roots showed some pink, but the plants apparently
were not checked in their growth. The Australian Brown variety
has proved very susceptible to pink root, jTet the hybrid grew vigor-
ously on infested soil throughout the season. Back crosses have been
made to the Australian Brown variety, but readings have not as yet
been made on resistance.
The smut disease, caused by the fungus Urocystis cepulae Frost, is
present in most of the onion-growing districts of the North. For-
maldehyde applied in the row at time of seeding is a satisfactory
control measure, but the cost of this treatment could be eliminated
by the development of resistant varieties. In 1925 Anderson (1)
suggested the use of Winterhecke as the logical parent for the breeding
of a smut-resistant onion by crossing. He states that it is almost
immune to smut, and by his description of the variety one is led to
believe that it is the Nebuka type of Allium fistulosum. In 1932 the
writer sent seed of the Nebuka to A. G. Newhall, of Cornell University,
who tested the seedlings under epidemic conditions and found them
to be practically immune to smut. Breeding work is under way at
present looking toward control by the use of resistant varieties.
Progenies involve crosses between the two species, A. cepa and
A.fistulosum. Only a few first-generation hybrid plants were secured,
and these have been self-sterile. Back crosses have been made to
both parents, however, but as yet these progenies have not been
subjected to resistance tests.
Mildew, caused by the fungus Peronospora schleideni Unger, is one
of the most destructive diseases to the onion seed crop. In Cali-
fornia losses may run as high as 80 percent in some seasons. Several
onion strains that are highly resistant to mildew have been isolated
by investigators of the California Agricultural Experiment Station.
One of these is a male-sterile strain of Italian Red, pedigree 13-53,
the leaves of which are highly resistant and the seed stems apparently
immune. Many progenies are now being tested under epidemic
conditions.
A disease called smudge, caused by the fungus Colletotrichum cir-
cinans (Berk.) Vogl., does considerable damage to the storage crop of
the North by causing bulb shrinkage and premature sprouting.
Walker, Link, and Angell {28) have shown that pigmented varieties
of onions are resistant to smudge, while the white are not. On pig-
mented onions the disease is confined mainly to the neck. Resist-
244 YEARBOOK, 193 7
ance is probably due mainly to the presence of protocatechuic acid —
one of the carbolic acids — which is in some way closely associated
with the yellow and red pigments in the dry outer scales of the bulb.
Insofar as known, this is the first case where resistance to a certain
disease has been shown to be due to a definite chemical constituent,
liieman {20), in a study of the relation of pigmentation to disease
resistance, states that the genes W (red) and Wy (yellow), which, are
responsible for the production of the red and yellow pigments, are also
responsible for the production of protocatechuic acid. Whether or
not resistance can be incorporated in the true-breeding white varieties
of onions remains to be determined .
According to Walker {22), pigmented onions are also more resistant
to the invasion of certain species of the fungus Botrytis {B. altii Munn,
B. squamosa Walker, and B. byssoidea Walker) . lie states that
resistance in colored bulbs appears to be due to a water-soluble toxic
substance in the outer scales that excludes the fungi. Colored bulbs
are not resistant once infection is established.
Yellow dwarf is a virus disease of onion that causes a characteristic
yellowing, wrinkling, twisting, and drooping of the leaves and dwarf-
ing of the plant. This disease was prevalent for a time in the Pleasant
Valley onion district of Iowa and has also been reported in other
districts. In a field test of 34 varieties in 1929 Henderson {10) found
that Sweet Spanish was the only variety showing marked resistance.
Plants of this variety did not contract the disease when inoculated
artificially and furthermore did not carry the disease in a masked
form. It will be rocalled that this same variety carries considerable
resistance to thrips and to pink root.
BREEDING FOR RESISTANCE TO INSECTS (THRIPS)
Thbifs are present wherever onions are grown, and it is estimated
that they cause more loss than all other insect pests and diseases com-
bined. Satisfactory chemical control has thus far been impossible,
because a large number of thrips are always protected between the
inner leaves of the plant, the pupal stage is spent in the soil, the species
is very prolific, the generations overlap, natural parasites are lacking,
and other host plants are numerous. The unsatisfactory control
secured by chemical means necessitates a mode of attack different
from that made in the past. Jones? Bailey, and Emsweller {11)
showed that certain varieties and species of onion have definite resist-
ance to thrips. Among the most resistant are White Persian, Nebuka,
California Early Red, Early Crano, and Sweet Spanish. Counts
made in 1932 and 1933 showed that the varieties used were resistant
in about the same order in both years, so that certain of their characters
evidently influenced the size of the thrips population per plant.
The White Persian variety (P. I. 86279), obtained from Persia
through the Division of Plant Exploration and Introduction of the
Bureau of Plant Industry, showed by far the most resistance (fig. 4) .
The resistance of this variety seems to be determined by certain
growth characters, which help to hold the thrips population to a
minimum, and perhaps by anatomical and physiological characters,
which help the plant to withstand injury. The shape of the leaves is
probably of importance in restricting the thrips population. In most
ONIONS
24,1
varieties the leaf blades have a flat side; iu opposite leaves these sides
are face to face and the young leaves are closely pressed together so
that the larvae are protected against insect enemies and adverse
weather conditions. In White Persian the leaves are almost circular
in cross section and protection is reduced to a minimum. The wide
angle between the two innermost leaves, especially in the young plant,
is another White Persian character that helps to restrict the thrips
population by reducing their protection to a minimum. Still another
character, probably of some importance, is the greater vertical distance
between the leaf blades, each new leaf extending its sheath farther
beyond the one encircling it than in other known cultivated varieties.
This habit of growth produces an extremely long sheath column.
Figure i. — Thrips-rcsistanl onions. The lliree rows to the left are the variety White
Persian (P. I. 86279); to the right are Australian Brown. Note the serious damage
done by thrips to the latter variety and the freedom of the White Persian from
injury. (From Jones, Bailey, and Emsweller, 11.)
If commercial varieties of onions had these leaf characters the thrips
population per plant would be reduced to a minimum and it would be
possible to secure more efficient control by spraying or dusting. The
shape and habit of leaf growth in the White Persian help to restrict
the number of thrips; other characters help the plants to withstand
injury, but these are as yet undetermined. Maughan and MacLeod
(16) are of the opinion that avoidance of the plant by the thrips, the
angle of contact of the leaves, the stage of growth of the plants, the
ability of the plant tissues to recover from injury, and probably other
influences have a bearing on resistance.
CROSSES BETWEEN SPECIES
The Nebuka type of Allium fistulosum has very little commercial
importance in the United States at the present time, but because of
its resistance to various diseases, insects, and adverse climatic condi-
2I(>
YEARBOOK, 193 7
tions it has become a valuable source of breeding material. Crosses
have been made between Nebuka and various important commercial
varieties of A. cepa by Emsweller and Jones (3), with the object of
incorporating certain resistance factors possessed by Nebuka into com-
mercial varieties of A. cepa. This species cross is rather difficult to
make, but with the aid of flies considerable numbers of first-generation
hybrid seed have been produced.
The Nebuka types are nonbulbing; the hybrids between them and
Allium cepa are intermediate in bulbing habit (fig. 5). Nebuka is a
perennial; A. cepa is a biennial; the hybrids between the two are
perennials, the tops remaining erect and the plants continuing to grow
Figure 5. — A, Commonly cultivated bulbing type of onion, Allium cepa, variety
Yellow Globe Danvers; B, Japanese onion, A. fistulosum, Nebuka type; C, first -
generation hybrid between the two. This species cross gives great promise for
breeding onions resistant to diseases and other adverse conditions (3).
as long as weather conditions are favorable. Although seed is pro-
duced in abundance by Nebuka, the plants continue to form divisions
at the base, and these can be used for propagation. In date of flower-
ing the hybrids are intermediate between the two parents. Nebuka
is usually in bloom 6 or 7 weeks before A. cepa. Blossoming occurs
irregularly over the entire inflorescence throughout the flowering period
in A. cepa, but in Nebuka the terminal flowers open first and blossom-
ing proceeds progressively toward the base. In the hybrid the ter-
minal flowers are the first to open, although with less precision than
in Nebuka; then a wave of opening extends toward the base, but this
does not terminate the blooming of the umbel, for blossoming then
continues for a time over the entire inflorescence as it occurs in A.
cepa. In A. cepa the perianth becomes fully expanded; in A. fistu-
losum it remains erect; the hybrid resembles the fistulosum parent very
ONIONS 247
closely. In the Nebuka varieties the leaves are circular in cross sec-
tion, whereas in most varieties of A. cepa the leaf blade is semicir-
cular; in the hybrid the semicircular type of leaf is dominant. Under
similar growing conditions the hybrids show more vigor than either of
the parents. They multiply rapidly by subdivisions at the base,
and should be able to increase and perpetuate themselves under nat-
ural conditions. The hybrids are practically self -sterile ; they are,
however, useful as pollen parents for back crossing to both A. cepa
and A. jistulosum. When the percentage of functional reproductive
bodies is very small, normal sperm cells are naturally more numerous
than normal egg cells, because of the much larger total number
produced.
PREMATURE SEEDING AND FREEZING INJURY
Premature seeding (bolting) occasionally causes heavy losses in the
early crop of the South and in those districts where an intermediate
crop is grown from dry sets or transplants. In central California the
percentage of bolting is high when a cool spring follows a warm fall.
A warm fall causes a large plant to develop. This size and cool spring
weather provide the proper combination of conditions for bolting,
according to Jones, Poole, and Emsweller (13). Because of the lower
temperatures prevailing along the central California coast, bolting is
more prevalent there than in the interior valleys, making it an ideal
place to select and breed nonbolting strains that may be useful else-
where. The difference in bolting habit between varieties is clearly
brought out by comparable plantings made in five locations in Califor-
nia during the season 1934-35. A few of the varieties, with the per-
centages of bolting, follow: Babosa, 73; Lord Howe Island, 66;
Earliest Express, 66; Early Grano, 63; Blood Red Rocco, 51; White
Italian Tripoli, 42; California Early Red, 19; and Italian Red, 17.
A selection out of Stockton Yellow Globe, strain 36-40, gave only 2
percent of bolters, while a selection out of Stockton Yellow, strain
21-l-3-4-S3, inbred for six generations, was entirely nonbolting.
These highly nonbolting strains are being used in crosses to incor-
porate this character into varieties that are prone to seed prematurely
when conditions favor.
MagTuder and Hawthorn (15) found varietal differences in resistance
to freezing injury, the soft-textured types of onion, such as Yellow
Bermuda, Crystal Wax, California Early Red, Extra Early Yellow,
and Italian Red, being the most susceptible.
GARLIC
The culture of garlic (Allium sativum), like that of onion, dates back
to time immemorial. Vavilov (21 ) gives middle Asia as the primary
center of origin and the Mediterranean region as the secondary center.
From these centers the culture of the plant has become worldwide.
It is highly prized for seasoning. Large collections of foreign varieties
of garlic have been secured by several States through the Division of
Plant Exploration and Introduction. These varieties vary widely in
such characters as number, size, keeping quality, color, and pungency
of the cloves, time of maturity, yield, resistance to thrips, and extent
of flower development. On some varieties flower stems have never
248 YEARBOOK, 1937
been observed to develop ; on others they reach a height of 4 to 6 feet
and contain umbels with a thousand or more flowers; and between
these two extremes there seem to exist all possible gradations. For
some reason, at present unknown, all varieties fail to produce seed.
Even on the profusely blooming Spanish and Creole types seeds have
never been observed. Because of the lack of sexual reproduction,
improvement must be secured entirely through the selection of bud
mutations.
CYTOLOGY AND GENETICS OF THE ONION 2
The onion has long been used as a source of material for studying
the behavior of the somatic and meiotic chromosomes. Emswellor
and Jones (4) studied the morphology of the chromosomes of the two
species Allium cepa and A. fistulosum, to develop a method by which
the chromosomes of a genom could bo identified, avoiding so far as
possible the use of total chromosome length. Chromosomes were
observed at the first division of the microspore, at which time they
are well spaced and only one of each pair is present. The length of any
individual chromosome when measured in different cells is not con-
stant because of lack of uniformity in stage of contraction and in
fixation. The constriction region is assumed to be located at a
definite point on the chromosome, making it possible at least at late
metaphase to recognize two arms, and a constant index figure can be
calculated by dividing the length of the short arm by that of the
long arm. Emsweller and Jones (5) have shown also that the type
of chiasma is gene-controlled. In A. fistulosum the chiasmata, at the
first metaphase, are localized at the constriction region, while in A.
cepa the chiasmata are placed at random. In the first generation
the chiasmata were at random as in the cepa parent. In back crosses
to A. fistvlosum chiasmata were localized in 10 plants and at random
in 7, indicating that the difference in type of chiasma is controlled
by a single gene, the localized type being recessive.
In a genetic analysis of the three bulb colors, red, yellow, and
white, commonly present in the cultivated onion, Rieman (20) found
that it was necessary to postulate five different genes to account for
the results secured — I, a gene for incomplete inhibition of color; i, a
gene allowing expression of color ; W, a gene< for red pigment ; Wy, a
gene for yellow pigment ; and w, a gene for white. The gene inhibiting
color, /, is dominant to its recessive allelomorph, %. The heterozygous
factor pair, Ii, produces red-necked and cream-colored bulbs in the
presence of the color genes W or Wy. The latter and the factor pair
Ii are inherited independently. The gene for red, W, is dominant to
the gene for yellow, Wy, and the gene for white, w. The color genes
are considered to be multiple allelomorphs.
Rasmusson (19) observed several abnormalities in chlorophyll
development, white, yellow, chlorina, and T-chlorina. The white
and yellow seedlings soon die. The chlorina form is yellowish at
first but later may become greenish. The T-chlorina is somewhat
paler in color than the chlorina and soon perishes. Some green
plants when selfed yielded progeny in the theoretical green to white
ratio of 15:1. Green and yellow, green and chlorina, and green and
s This section is written primarily for students and others professionally interested in genetics or breeding.
ONIONS 249
T-chlorina in each case occurred in a ratio of 3:1, but in some cases
green and chlorina were in a ratio close to 1 5 : 1. Green : chlorina : white
occurred in the ratio of 9:3:4, as did green: chlorina: yellow.
LITERATURE CITED
(1) Anderson, P. J.
1925. COMPARATIVE SUSCEPTIBILITY OP ONION VARIETIES AND OF SPECIES
op allium to urocystis cepulak. Jour. Agr. Research 31:
275-286.
(2) Bailey, L. II .
1924. manual op cultivated plants. . . 851 pp., ilhis. New York
and London.
(3) Emsweller, S. L., and Jones, H. A.
1935. an interspecific hybrid in allium. Hilgardia 9: 265-273, illus.
(4) ■ and Jones, H. A.
1935. meiosis in allium fistulosum, allium cepa and their hybrid.
Hilgardia 9: 277-294, illus.
(5) and Jones, H. A.
1935. A GENE FOR CONTROL OP INTERSTITIAL LOCALIZATION OP CH1ASMATA
in allium fistulosum l. Science (ti. s.) 81: 543-544.
(6) Erwin, A. T., and Harter, W. L.
1925. A STUDY OP THE ONION INDUSTRY IN PLEASANT VALLEY, IOWA.
Iowa Agr. Expt. Sta. Bull. 225, pp. [2591-286, illus.
(7) Felix, E. L.
1933. disease resistance in allium fistulosum l. (Phytopath. note)
Phytopathology 23: 109-110.
(8) Garcia, F., and Fite, A. B.
1931. early guano onion culture. N. Mex. Agr. Expt. Sta. Bull. 193,
15 pp., illus.
(9) Hedrick, U. P., ed.
1919. sturtevant's notes on cultivated plants. 686 pp., Albany.
(Now York State Dept. Agr. Ann. Rept. 27, v. 2, pt. 2.)
(10) Henderson, W. J.
1935. YELLOW DWARF, A VIRUS DISEASE OP ONIONS, AND ITS CONTROL.
Iowa Agr. Expt. Sta. Research Bull. 188, pp. 211-255, illus.
(11) Jones, H. A., Bailey, S. F., and Emsweller, S. L.
1934. thrips resistance in the onion. Hilgardia 8: 215-232, illus.
(12) ■ and Emsweller, S. L.
1934. the use op plies as onion pollinators. Amer. Soc. Hort. Sci.
Proc. 31: 160-164, illus.
(13) Poole, C. ¥., and Emsweller, S. L.
1935. bolting habit in the onion. (Abstract) Amer. Soc. Hort. Sci.
Proc. 33: 490. .
(14) Maghuder, R., and Allard, H. A.
1937. BULB FORMATION IN SOME AMERICAN AND EUROPEAN VARIETIES OF
onions as affected by length OP day. Jour. Agr. Research
54: 719-752, illus.
(15) ■ and Hawthorn, L. R.
1935. EFFECTS OP FREEZING AND COLD WEATHER ON IMMATURE ONIONS.
U. S. Dept. Agr. Circ. 355, 12 pp., illus.
(16) Maughan, F. B., and MacLeod, G. F.
1936. FURTHER STUDIES ON ONION VARIETIES AND ONION TIIRIPS. Jour.
Econ. Ent. 29: 335-338.
(17) Morse, L. L.
1923. field notes on onions. 48 pp., illus. San Francisco.
(18) Porter, D. R., and Jones, H. A.
1933. resistance of some of the cultivated SPECIES OF ALLIUM TO
pink root (phoma terrestris). Phytopathology 23: 290-298,
illus.
(19) Rasmusson, J.
1920. mendelnde ciiloropiiyllpaktoren bei allium cepa. Hereditas
1: [128J-134.
138904°— 37 17 ++
250 YEARBOOK, 1937
(20) RlEMAN, G. H.
1931. GENETIC FACTORS FOU PIGMENTATION IN THE ONION AND THEIB
relation to disease kesistance. Jour. Agr. Research 42: 251-
278, illus.
(21) Vavilov, N. I.
1935. fBOTANICAL-GEOGRAFHIC PRINCIPLES OF SELECTION.] 60 pp. MoS-
kva, Leningrad. [French tra/isl. in Rev. Appl. Hot. 10: 124-129,
214-223, 285-293. 1930.]
(22) Walker, J. C.
1926. botrytis neck rots of onions. Jour. Agr. Research 33: 893-
928, illus.
(23) Link, K. P., and Angell, H. R.
1929. • CHEMICAL ASPECTS OF DISEASE RESISTANCE IN THE ONION. Natl.
Acad. Sci. Proc. 15: 845-850.
BREEDING AND
IMPROVEMENT
OF PEAS AND BEANS
B. L. WADE, Senior Geneticist, Divi-
sion of Fruit and Vegetable Crops and
Diseases, Bureau of Plant Industry
N,
PEAS
I ATURALISTS have been interested in Pisum for several hundred
years, and there arc many unmistakable references to peas in the
writings of the old Greeks and Komans. Columbus' is reported to
have grown peas on Isabella Island in 1493, and General Sullivan
destroyed the growing peas of the Indians in western New York in 1779.
Pickering (50)1 states that of the culinary vegetables Pisum sativum
is the only kind that can with any certainty be traced back to the
Stone Age. It was uncommon for peas to be eaten in other ways
than as dry, cooked seeds before 1700.
Much of the history of Pisum has been well reviewed by Hedrick,
Hall, Hawthorn, and Berger (14). Ruellius in 1536 was the first
to distinguish between garden and field peas. Since Pisum sativum
L., the garden pea, and P. arvense L., the field pea, are completely
cross-fertile, the distinction seems entirely artificial, and most writers
now consider both types under P. sativum. In addition some varieties
of garden and canning peas (unquestionably P. sativum) are used
extensively for field peas.
It is noteworthy that peas were the first crop with which controlled
breeding work for the production of new varieties was begun, and also
that they were the crop with which Mendel conducted his historic
experiments, which were the beginning of the modem science of
genetics.
Vavilov (80) indicates that peas probably had their origin in Ethi-
opia, with secondary centers of diversity in Mediterranean Europe
and in southwestern and central Asia. Although many forms are
known in the Mediterranean region, peas have never been of much
importance in that area. Farther north, in England, peas have
reached their greatest perfection, and they are an important crop in
Scandinavia, Germany, the Netherlands, and France. The Union of
Soviet Socialist Republics at the present time probably surpasses all
other countries in the production of peas, mostly dry edible seeds.
In 1929 the acreage of peas for grain in the Union of Soviet Socialist
Republics was 1,435,750 acres. The estimated crop for 1931 was
2,750,000 acres.2 Further increases are anticipated. The United
States pea acreage for all purposes probably docs not exceed 1,000,000
acres.
i Italic numbers in parentheses refer to Literature Cited, p. 277
s Communication from E. K. Bonnett, Moscow, Idaho, 1931.
251
252 YEARBOOK, 1937
The pea. is a vegetable easily introduced in most places where the
climate is favorable. The plants of many varieties are cold-hardy and
will survive a winter under a snow covering. If slightly frozen they
will put out now shoots when the weather becomes warmer. The
blossoms are not particularly cold-tolerant and will survive only a
light frost. Peas do not thrive very well in warm weather, so their
culture in the southern and southwestern United States is confined
largely to the winter and spring months. In the southern part of the
Union of Soviet Socialist Republics, where summer quickly follows
winter, peas are grown to a limited extent. In the north-central part
of the Union of Soviet Socialist Republics, east of Leningrad, west of
Moscow, and in southwestern Siberia they are a very important crop.
Peas may be divided into at least five classes according to use:
(1) Forage or green-manure crops, (2) dry, edible seeds, (3) market-
garden or green shelling peas, (4) canning peas, and (5) edible-podded
peas, which have no lining membrane in the pod, a condition that has
been traced to two genes. The Union of Soviet Socialist Republics
and the southern United States devote large acreages to forage and
green-manure crops. Nearly all the important pea-producing coun-
tries devote large areas to the production of seed for food and feed-
stuffs, especially the Union of Soviet Socialist Republics, German3r,
the Netherlands, and the area around Spokane, Wash., in the United
States. Classes 1 and 2 above are usually referred to as field peas.
California produces more than two-thirds of the market-garden or
truck peas grown in the United States, of which the annual acreage is
now well over 100,000 acres.
The climate of England is especially favorable to the production of
large-podded market-garden peas of high quality.
Lately the preservation of shelled green peas by freezing has become
important in some parts of the United States, particularly the Pacific
Northwest. This industry uses both market-garden and canning
varieties, but several seedsmen are now working to develop varieties
especially adapted to freezing.
THE most highly evolved pea variety so far produced hy breeders
is probably Laxton's Progress. It has a very dwarf vine with a
zigzag stem, which makes it sturdy and upright; dark-green
foliage; and large, straight, dark-green, pointed pods, from which
the peas can be shelled readily. Each of these characteristics is
important to growers and each received attention in breeding.
The most notable characteristic of Progress, however, is that it
begins to bloom at the eighth or ninth node on the stem. This may
not seem significant to the inexperienced, but to pea farmers it is
worth years of difficult breeding work; for it means that Progress
is a few days ahead of its nearest rival in excellence, Hundredfold,
which does not begin to bloom until the ninth or tenth node.
PEAS AND BEANS 253
The United States cans annually from 12,000,000 to 20,000,000 cases
of peas,3 mainly in the States of Wisconsin, New York, Maryland,
Michigan, and Washington. The canning of peas is not an extensive
industry in any other country at present. Edible-podded peas arc
widely grown in continental Europe. They are for the most part more
tolerant to heat than are other peas and have now become a rather
common vegetable in Hawaii and southern China. In the continental
United States they are practically limited to home gardens.
Origin of the Older Varieties
Thomas Andrew Knight, of Downton Castle, Wiltshire, England,
the first great hybridizer, began his work with peas in 1787. Some
of his varieties are still used, and they have been the foundation
breeding stock for most modern pea varieties.
In 1822 John Goss published a paper in which he recognized the
dominance of yellow cotyledons and that green segregates from his
crosses bred true. If he had carried his observations a little farther
he would have antedated Mendel's discoveries by some 40 years.
Succeeding Knight, many famous pea breeders began their work
in England. About 1860 McLean, of Colchester, produced little
Gem and his important Advancer, from which the American varieties
Abundance and Perfection were derived. Thomas Laxton bred the
variety that bears his name, introducing it in 1898. Laxton Bros,
later produced Laxtonian about 1907, and Progress in 1921.
Culverwell originated Telegraph, a smooth-seeded variety with
long pods and a tall vine, some time before 1877. It became very
popular both in England and in the United States. Telephone, a
wrinkled-seeded strain of Telegraph, was derived from Telegraph by
Carter in 1878, and has largely replaced it, probably on account of
its much better quality. Alderman, introduced by Laxton about 1891,
has largely replaced Telephone in the United States, probably because
of the demand for darker pods.
Several English seed companies have for at least 50 years poured
a continuous stream of new varieties into the markets of the world.
Most of these have been successful only in England, but such a
diversity of varieties has been supplied that most countries find them-
selves using a number of varieties that originated in England. The
principal English seed companies contributing to pea improvement
have been Laxton Bros., Sutton & Sons, Carter & Co., and Hurst & Co
All American varieties are undoubtedly similar to English varieties
and in many cases confusion exists as to the origin of a given variety.
Alaska was introduced as an American variety by A. B. Cleveland
about 1880. It is so similar to the English variety Earliest of All, a
cross of Ringleader X Little Gem, introduced in 1881 by Laxton,
that these two varieties are now indistinguishable. Alaska is a smooth-
seeded, very early, straight-stemmed variety with light-green pods
and foliage, which typically begins blooming at the eighth node.
Dwarf Telephone as now grown is a midseason variety blooming
at about the fourteenth node. The vino is a sturdy dwarf with a
zigzag stem, and the pods and foliage are light green. The pods are
long and pointed. Introduced in 1888, the variety is now inextricably
3 A case equals 2 dozen 20-ounce cans. ■
254 YEARBOOK, 1937
mixed and apparently synonymous with Daisy, although originally
different. It originated in the United States as a cross of Stratagem X
Telephone, while Daisy had its origin in England as a cross of Stratagem
and an unnamed variety. Daisy was introduced by Carter about 1891 .
Potlatch (Leonard, 1906) is now synonymous with Stratagem
(Carter, 1879). These are essentially the same as Dwarf Telephone
except that they both have dark-green pods and foliage.
Current Important Varieties
The advent of the canning industry in the United States about 1850)
and technical improvements in canning machinery about 1890, gave
a great impetus to American pea breeding, and at present the United
States produces about as many varieties as are imported from England.
The practice of renaming makes it difficult in many cases to be certain
of the origin of a variety, since a single name may serve for several
closely related varieties, or a single variety may have many names.
The peas with which Knight began his work were smooth-seeded,
mostly tall (though a few were dwarf), late, and small podded. The
records do not show how he obtained his first wrinkled strain, but he
combined the wrinkled characteristic with somewhat larger pods.
The quality of sweetness brought in by the wrinkled characteristic
soon made his varieties popular, not only in England but in con-
tinental Europe.
The English breeders have given but scant attention to disease
resistance, but they have gone ahead vigorously to produce larger
pods, higher yields, better quality, earlier straius, and sturdier types
of vines.
When the early pea breeders began their work, they were interested
in dual-purpose peas, that is, peas that could be used in the green-
shell condition and also dry. As peas became a more popular vegetable
more emphasis was placed on desirable characteristics for a green
shelling pea until varieties were developed solely for that purpose.
In the early days peas for porridge were cooked whole and consequently
both smooth and wrinkled peas could be used. At the present time
most dry peas for cooking purposes are sold in a hulled, split condition.
As wrinkled peas split with, difficulty and it is extremely difficult to re-
move the hulls, they are no longer produced commercially for cooking
in the ripe, shelled condition.
The most highly evolved pea variety so far produced is probably
Progress (Laxton Bros., 1921). It has a very dwarf vine, with a
zigzag stem — that is, the nodes are not straight but are set at com-
pensating angles so that a very sturdy, upright plant is produced —
the pods and foliage are very dark green, and the pods are very large
and straight with pointed ends. Progress begins to bloom at the
eighth or ninth node and Hundredfold at the ninth or tenth. To the
inexperienced there may be no essential difference between Hundred-
fold and Progress, but to the plant breeder and pea farmers it is
worth years of difficult breeding work to have a variety that is a few
days earlier than Hundredfold and with pods slightly larger than
some strains of Hundredfold. Many peas that have competed with
Hundredfold and Progress — such as Blue Bantam (Burpee, 1912),
Peter Pan (Watkins and Simpson, 1910), and Laxtonian (Laxton
PEAS AND BEANS 255
Bros., 1907) — have failed because of their light-green pod color,
slightly smaller pod size, slight pod curvature, tightness of peas in
the pod, or some other slight difference of commercial importance.
Before the advent of large-scale shipping of market-garden peas
there was no particular reason why varieties with dark-green pods
should be preferred to light. However, retail customers began to
believe that the light-green pod color was associated either with over-
ripeness or staleness of the product, so that today no popular market-
garden variety has a light-green pod.
This brings us to the questions of synonyms and misnaming. If
a seedsman had a good trade in Laxtonian he might not object to
selling Progress or Hundredfold to his customers as Dark-Podded
Laxtonian, especially if his customers inquired whether he could not
furnish them with a dark-podded strain. After a few years the dark-
podded designation might be dropped and the new variety sold
under the old name of Laxtonian. As a matter of fact, in 1928 nearly
all strains of Laxtonian had light-green pods, while of the strains
examined in 1935 all had dark-green pods except one. Most of the
Laxtonian sold in 1935 appeared to be the Hundredfold of 1928,
whereas the Hundredfold of 1935 is an improvement over the original
strain, with pods that under the best of conditions may be larger than
those of Progress.
This process has probably been repeated in practically all groups.
In the midseason group (late varieties of peas are not grown in the
United States) Daisy and Dwarf Telephone were at first hopelessly
confused and then reduced to minor importance in competition with
dark-podded Stratagem and Giant Stride. In some places consider-
able quantities of Dark-Podded Dwarf Telephone are sold, but the
variety is in reality only a strain of Stratagem. Giant Stride is a
Stratagem type, excellent for shipping on account of its very heavy
pod walls. „ TT . .
Canning Varieties
The canning of peas did not attain much popularity in this country
until around 1900. There were no canning varieties, and canners
tried various market-garden types. They found that they needed
characteristics in their canning varieties that market gardeners
would find disadvantageous. For instance, they wanted peas with a
maximum number of seeds in the edible condition at one time, while
the market gardener desired his varieties to produce over a longer
period.
In the canning varieties very large pods have been purposely
avoided, since they are not particularly well adapted to "vining"
machinery, and the yield of shelled peas per acre from large-podded
varieties is usually considerably less than from small-podded varieties
of the same time of maturity. The early varieties of canning peas
all have straight stems with relatively long internodes. This makes
them convenient to harvest on poor soils, since early peas with zig-
zag stems would not make growth enough to be handled effi-
ciently by machinery. Alaska and Surprise are typical of this
group and both begin to bloom at the eighth or ninth node. The
small pods crack open readily under the impact of the beaters of the
pea viner.
256 YEARBOOK, 1937
The later canning varieties all have zigzag stems except the Ad-
mirals, and the pods are usually borne in pairs, although under adverse
environmental conditions single pods may be produced. Perfection
blooms typically at the fourteenth node. It deviates slightly from
Advancer in shape of pod apex and yield, and slightly from Abundance
in tightness of pod and node of bloom. Practically all canning peas
have light-green pods and seeds, in contrast to the successful market-
garden varieties. In an attempt at competition with the market-
garden and frozen peas, some cannors have canned varieties with
dark-green seeds.
The group of peas usually known as Gem has furnished prac-
tically all our canning peas. At the time canning became popular,
various Gem types were losing their popularity in competition with
large-podded market-garden varieties. Canners found, however, that
the Gem types that shelled with some difficulty by hand could be
shelled easily by machinery and that the yield per acre would be
larger than for large-podded peas. The Gem group might be charac-
terized as having on various types of vines, blunt or nearly blunt, well-
filled pods of small to medium size, not exceeding %% inches in length.
From this group, light-green varieties with good to high productiveness,
poor to high culinary quality, and early to midseason maturity were
selected or bred for canning purposes. There is no popular canning
pea with a pointed pod, although many such varieties have been
introduced.
Alaska is a smooth-seeded pea with some of the quality of Little
Gem, although this quality is not evident in the larger siftings or older
seeds from this variety. Alaska retains its prominence largely because
of its hardiness under adverse conditions, and the canned product is
popular in restaurants, where a fairly tough product is desired that
will stand up well after reheating.
Advancer was developed by McLean about 1860 as a market-garden
variety. It was from a cross of Beck Gem with some other wrinkled
variety. Perfection is of better quality than Advancer and is derived
from it by selection. Practically all strains now offered as Advancer
are in reality Perfection. Differences in Perfection and Advancer are
difficult to stateexactly, but in general the Perfection pods are slightly
larger and the yield is somewhat greater under comparable conditions.
Perfection, and improvements from it, now constitutes the most
important midseason canning pea variety.
Surprise (Horsford, 1889), from a cross of Earliest of All X American
Wonder, is one of the best-quality peas known. It is in season with
Alaska and before maturity can be distinguished from Alaska only with
difficulty. The major difference seems to be a greater amount of
marbling on the stipules of Surprise.
Prince of Wales is a large-seeded Gem type, somewhat later in season
than Perfection, but even under the best of conditions the pods do not
fill well. It is popular in limited areas for the canning of peas ungraded
as to size, of a darker green color than Perfection.
Many seed companies are now attempting to develop pea varieties
especially adapted to preservation by freezing. Perhaps the ideal
freezing varieties will have relatively large seeds and medium-sized
pods that can be handled by the vining machinery now used for
PEAS AND BEANS 257
canning varieties. To be successful as a variety for freezing, the
seed color must be dark green without developing a bronze tone
when the pack has been thawed.
Summary of Varieties
A summary of the principal varieties in common use at the present
time includes —
Canning peas: Market-garden peas — Continued.
Alaska Thomas Laxton
Perfection Early Gilbo
Surprise Dwarf Telephone
Prince of Wales Stratagem
Green Admiral „. . , ,, ... , ,
Yellow Admiral Ficld Peas (dl7 edlble a,ld cover"
crop groups) :
Market-garden peas: Alaska
Progress Blue Bell
Hundredfold First and Best
Giant Stride Extra Early
Alderman White Canada
World Record Austrian Winter
Gradus
Of the six canning varieties listed, only two are of undoubted English
origin — Prince of Wales (Green Giant) and Yellow Admiral (Fair-
beard Nonpareil) — and both are of minor importance. Green Ad-
miral, also of minor importance, was derived by selection by Rogers
from Yellow Admiral. Alaska has been subjected to intensive breed-
ing work by Delwiche, Renard, Rieman, Wade, and Temple, espe-
cially for resistance to fusarium wilt. Perfection (Gallatin Valley
Seed Co., 1914), derived from Advancer, has been the subject of much
breeding work for wilt resistance by Renard, Delwiche, and Wade.
New wilt-resistant Surprise types, derived from crosses of Surprise X
Alaska or Surprise X Peerless, have been bred by Delwiche, Wade, and
Renard.
Of the market-garden types none is of undoubted American origin
except Early Gilbo (Rogers, about 1934). The three of greatest im-
portance are unquestionably of English origin. The greatest contri-
bution of American seedsmen to the English market-garden varieties
lies in their selection of pure lines in which the incidence of "rabbit
ear" and other rogues is very low. Rabbit ear is a condition in which
the leaves, stipules, and pods are greatly reduced in width while retain-
ing approximately the same length, so that at a distance the stipules
look like the ears of a cottontail rabbit.
In the field-pea group Alaska is again first. Blue Bell, which
probably originated in continental Europe, had its name changed from
Blue Prussian during the World War. First and Best and Extra
Early are of American origin. White Canada and Austrian Winter
are probably from the countries indicated by the names. Little effort
has been expended in developing varieties suitable for field peas. The
University of Idaho strain of Blue Bell, named Idabell, is a superior
strain of that variety. Some seed companies that grow a great many
ficld peas possess pure lines that, in their freeedom from offtypes, are
equal to some of the best strains of canning peas.
258 YEARBOOK, 1937
Origin and Evaluation of New Varieties and Strains
The Wisconsin Agricultural Experiment Station group working
with canning peas have greatly influenced, the trend in the industry.
E. J. Delwiche has been prominent in this work and has contributed
at least 11 strains, of which Badger (1921), a variety like Perfection,
was the first introduction. Badger is of exceptionally high quality,
but the canning trend away from small seeds and susceptibility to wilt
has prevented its general use. Horal (1923), a small-vined Perfection
type, one of the heaviest-yielding peas known to the canning industry,
failed to achieve popularity because of its very decided lack of quality
coupled with small seed size. Alcross and No. 19 strains of Alaska
have been of value in breeding homozygous wilt-resistant strains of
Alaska peas. They are still grown to a considerable extent, and some
of the completely wilt-resistant strains of Alaska on the market have
been selected from them. Ashford (1924) is an exceptionally good
strain of Horsford, but it is later than Perfection, and therefore the
demand for it is very limited. Wisconsin Early Sweet (1931) is a
vigorous wilt-resistant type approaching Surprise in quality and hav-
ing the hardiness of Alaska. It promises to become a very important
variety. Wisconsin Perfection (1933) has achieved some popularity
on account of its hardiness and wilt resistance.
The Canners Seed Corporation has introduced several new strains
of peas since 1930. These have all resulted from the breeding work
of E. J. Renard. All introductions by this company have been pure
(homozygous) for wilt resistance and were bred especially for adap-
tation to conditions in Wisconsin. Wilt-resistant Perfection (1930),
wilt- resistant Alaska (1930), and wilt-resistant Early Perfection (1933)
have been very favorably received by the canning trade. The popu-
larity of large-seeded Perfection and Improved Wales will depend on
the trend of the canning industry toward or away from large-seeded
types.
The Washburn -Wilson Seed Co. has introduced several strains of
completely wilt-resistant peas since 1932. These are for the most
part the result of breeding work carried on by the writer. The most
successful of these seem to be Walah (1932), from Prince of Wales;
Alah (1932), which is a wilt-resistant Alaska; and Mardelah (1935),
a wilt-resistant Surprise type.
C. E. Temple, of the Maryland Agricultural Experiment Station,
has originated a strain of Alaska that does well under conditions
existing in Maryland and adjoining States. It is resistant to fusarium
wilt (caused by Fusarium orthoceras Appel and Wr. var. pid Linford)
and possibly to certain other diseases.
Stuart F. Smith, of the Sioux City Seed Co., has produced wilt-
resistant strains similar to Alaska and Perfection. M. C. Parker, of
the Gallatin Valley Seed Co., is breeding peas for fusarium wilt re-
sistance, types for freezing, and types with multiple pods.
It would appear from the emphasis on wilt resistance that fusarium
wilt has been of great importance in the United States. To a con-
siderable extent it has been important, even the limiting factor in
certain areas. Probably the most interesting thing in connection
with the work on fusarium wilt has been the general adoption of pure-
PEAS AND BEANS 259
line breeding by the seed companies. It was found that most stocks
of partially wilt-resistant strains did not give good canning results,
on account of the mixture of prematurely ripened peas from susceptible
plants with the normal peas from the resistant plants. After it was
found that pure lines were highly satisfactory in the wilt work, pure-
line methods were used in connection with other seed stocks, so that
the standards of the industry with regard to rogues have been very
definitely raised.
Much confusion usually exists in the seed industry as to the exact
identity of strains. It is not improbable that some one strain of wilt-
resistant Alaska or other varieties may come to be considered of out-
standing merit. However, with the lapse of time and the tendency
to substitute similar things for each other, confusion will arise as to
the actual strain employed. Many companies have found that wilt-
resistant Alaska and wilt-resistant Perfection are entirely satisfactory
as canning peas and cannot be distinguished in any definite way
from corresponding susceptible biotypes except in reaction to wilt,
so that they feel justified in carrying only one strain of each major
variety. New York State apparently does not have a wilt problem,
but many of the Alaska and Perfection stocks delivered in that State
are wilt-resistant.
The future canning types for this country are rather unpredictable,
but it seems likely that early peas with stems like Alaska or Surprise,
and later peas with heavier stems like Perfection, will be in demand.
Large-seeded strains are being sought for the canning of ungraded
"sweets", but so far they have not given entirely satisfactory yields.
Resistance to diseases other than wilt, to insects, and to adverse
weather conditions all are problems that will be worked on in the near
future by plant breeders, and in .some cases such work is already
under way. Searles, at the Wisconsin Agricidtural Experiment
Station, is doing some work on tolerance of pea varieties to aphid
injuries.
Among the market-garden types, Progress (Laxton Bros., 1921)
is the most important variety. Hundredfold (Sutton, 1910) is next
in. importance. These two varieties have largely replaced similar
varieties like Laxtonian, Blue Bantam, Pioneer, and Peter Pan.
Giant Stride (Carter, 1916) is now probably third in importance. It
has largely replaced Dwarf Telephone and Stratagem in the western
United States. As introduced it was quite a variable strain. Asgrow
No. 40 and Stridah are pure-line selections from Giant Stride or
similar material introduced in 1930 and 1931. Recently the United
States Department of Agriculture, partly in cooperation with the
California Agricultural Experiment Station, has proceeded with
crosses between Giant Stride and Progress in. which desirable early
Progress and Hundredfold types have been selected for resistance
to strains of Fusarium.
Seed stocks handled under the name of Alderman consist essentially
of two types. One type is true Alderman (Laxton, about 1891) and
is extensively grown in home gardens where a variety adapted to
trellising is desired, and to a limited extent in commercial market-
garden areas. The other type is common in the truck-farming areas
of the West and is either Quite Content (Carter, 1906) or a derivation
260 YEARBOOK, 1937
from a cross of Alderman with Quite Content. The largest pods and
most fancy packs of market peas obtained in the United States are
made from this second type of Alderman, which really deserves a
name of its own. Sometimes it is referred to as long-pod Alderman,
or Alderman with some geographic designation. The best way of
differentiating between the Alderman types is by noting pod-wall
thickness. The old type of Alderman has a thin pod wall and the
new type has a much thicker pod wall.
Early Gilbo (Rogers, about 1934) is an exceptionally promising
variety midway in season between Hundredfold and Giant Stride.
The pods are straight, well-filled, approximately as large as those of
Giant Stride, and moderately thick walled.
Gradus, Thomas Laxton, and World Record are popular in certain
areas in the eastern United States, but the pods are so small that
western shippers do not use them. These are all early, straight-
stemmed varieties blooming at the eighth to tenth nodes. Thomas
Laxton has blunt pods, the other two have pointed pods.
Many American seed companies have contributed to the introduc-
tion or breeding of superior varieties and strains of peas. Among these
should be mentioned Associated Seed Growers, Inc., and their prede-
cessor firms, the Everett B. Clark Seed Co., the John H. Allan Seed
Co., and N. B. Keeney & Sons; the Ferry-Morse Seed Co. and their
predecessor firms, D. M. Ferry & Co. and C. C. Morse & Co.; the
Rogers Bros. Seed Co.; the Washburn- Wilson Seed Co.; the Gallatin
Valley Seed Co. and its predecessor firm, the Davis Seed Co.; the
Canners Seed Corporation; the Sioux City Seed Co.; W. Atlee Burpee
& Co.; the Jerome B. Rice Seed Co.; Francis C. Stokes & Co. and their
predecessor firms; the Chas. IT. Lilly Co.; the Livingston Seed Co.,
and Vaughn's Seed Store.
SNAP BEANS
History and Use
Beans (Phaseolus vulgaris L.) were introduced from the Americas to
Europe and Asia, where they early became popular. They were
mentioned in Europe about 1542, and by 1616 a large number of
varieties of different types were described. Hcdrick, Tapley, Van
Eseltine, and Enzie (15) have given a very satisfactory summary of
the early history of beans and descriptions of varieties now grown or
once grown in the United States. The most extensive previous
studies of bean varieties were made by Irish (17), Tracy (77), and
Jarvis (18).
Beans may be divided into three major classes according to form
in which they are harvested and used — (1) dry shell, (2) green shell,
(3) snap or green beans. There is some overlapping of these groups.
For instance, Canadian Wonder is thought of as a dry shell bean in
this country but is considered a good snap bean in parts of the British
Empire. Low Champion as used falls in all three categories. Snap bean
varieties may be further divided into (a) market garden, (b) home
garden, and (c) canning beans, but distinctions on such a basis are not
particularly valid, since most of the canning beans are frequently
used for the other two purposes. Most of the present discussion will
be concerned with snap bean varieties and their development.
PEAS AND BEANS 261
Beans are also classified according to type of vine and pods. A
bush bean is a type in which the inflorescence is at the tip of the
plant ; when it appears, the plant stops growing. In a pole bean, on
the other hand, the flowers are along the stem, which continues to
grow indefinitely, its ultimate length depending on environmental
conditions. All bean pods arc green when they are very small, but
some turn white, yellow, or crystal 4 as they approach an edible
stage. The latter types are called wax beans. Pole beans are mostly
used for home gardens. Wax beans are everywhere less popular than
green, but they are used for canning, shipping, and home gardens.
Since wax pods readily show spots, there has been some discrimination
against them in sections where pod-spotting diseases are common.
From a shipper's standpoint beans are also classified as flat or round.
Beans heart-shaped or oval in cross section arc usually classed with
the round group, and any pod with a diameter in one direction less
than 80 percent of the diameter at right angles to it is considered flat.
At the present time Florida produces well over half the shipping
crop of market-garden snap beans. New York, Maryland, Wis-
consin, Michigan, and Colorado produce a large part of the crop for
canning. Origin of the Older Varieties
An interest in early bean varieties with stringless pods gave the
initial impetus to American bean breeding about 1890. Previous
to that time seed companies had given but scant attention to bean
breeding, apparently being content to introduce a selection made by
a farmer or a variety that had become common in some farming
community. White Kidney (shell), Dutch Caseknife, Lazy Wife
(pole), Early Yellow, Six Weeks, and Mohawk go back too far in
horticultural history to be traced with any degree of certainty. Wax
beans seem to have been introduced from Europe when Algiers (wax
pole) was brought to this countiy, and German Black Wax (bush)
was introduced about 1865.
Even after seed companies became interested in improvement work
it was confined mostly to selections from existing stocks or to developing
progenies from chance crossings. The seedsmen were seeking early
varieties with less fiber in the pod walls and a reduction or elimination
of strings as well as a certain smoothness of pod, and in some cases
they considered an increase in pod size important. However, these
seedsmen gave only incidental attention to offtypes appearing in
their stocks, and progress was not very rapid.
The most successful of these early plant breeders was Calvin N.
Keeney, of Le Roy, N. Y. Among his productions are Pencil Pod
Black Wax, Brittle Wax, Rustless Golden Wax, Wardwell Wax,
Burpee Stringless Green Pod, Surecrop Stringless Wax, Giant String-
less Green Pod, and one strain of Stringless Green Refugee. These
varieties were all stringless and of very high culinary quality when
compared with such varieties as Early Six Weeks and Mohawk, and
they all became popular in spite of the fact that they were not quite
so hardy as the older varieties. Brittle Wax has persisted as the most
popular wax for canning, and Stringless Green Refugee is still the
most satisfactory type for canning high-quality green beans. Pencil
* Crystal is the term used to describe a nearly colorless, rather translucent-appearing pod.
262 YEARBOOK, 1937
Pod Wax is of very high quality, but the tendency for the pods to
curve has kept it from being a popular garden or shipping bean, and
the black seed has prevented it from attaining great popularity as a
canner. At the time, however, Burpee Stringless Green Pod was
sensationally successful and was grown in most home gardens as well
as for canning and shipping. The great success of this one variety
stimulated Keeney, as well as other breeders, to continue the devel-
opment of new stringless varieties, while Burpee Stringless Green
Pod remained very popular with home and market gardeners, and
Giant Stringless Green Pod became the favorite for an early canning
variety for packs of cut beans. Part of Keeney's varieties were
introduced by the W. Atlee Burpee Co., part by himself. During the
last few years the Keeney stocks have been consolidated with those of
two other seed companies incidental to the formation of the Associated
Seed Growers, Inc.
D. G. Burlingame, of Genesee County, N. Y., introduced Bountiful
in 1898. Other early plant breeders were A. N. Jones, of Le Roy,
N. Y. ; W. H. Grenell, of Pierrepont Manor, N. Y.; and John Kramer,
of Doylestown, Pa.
At the present time the most popular flat-podded, early green snap
bean for shipping is Bountiful. There is some competition among
early round pods, but Black Valentine (Henderson, 1897), New
Stringless Green Pod (Associated Seed Growers, Inc., 1930, from
Tendergreen, Henderson, 1922), Full Measure (Henderson, 1906),
Burpee Stringless Green Pod, and Giant Stringless are the most
popular. Red Valentine, a very old bean of uncertain origin, is still
used to a small extent. In some sections Stringless Green Refugee
(Keeney, 1908) and 1000:1 Refugee (a very old variety) are still
used for late shipping beans. The former is also the most important
late canning bean where a high quality pack is desired.
Among the wax beans, Hodson Wax (Harvey Seed Co., 1902) is
the most popular late shipper. Webber Wax (1913), Sure Crop Wax
(Keeney, 1911), and Davis White Wax (Davis, 1895) are popular
early flat waxes for shipping. Brittle Wax (or Round Pod Kidney
Wax), Improved Kidney Wax (Keeney, 1906), and Pencil Pod Wax
(Keeney, 1900) are the most important of the wax beans for canning
Disease as a Factor in Bean Culture
The ravages of diseases early made it necessary for plant breeders
to do additional work on the varieties introduced by Keeney and
others after 1890. The three most important bean diseases in this
country are caused by organisms that invade the seed tissues, remain
dormant in them, start new outbreaks on the seedling plants, and cause
losses later. These diseases are anthracnose, bacterial blight, and
mosaic.
Anthracnose of beans results principally in dark, sunken spots
on the pods, which make such beans unmarketable. In the case of
dry shell beans the seed may be discolored. Anthracnose can be
eliminated from any stock of seed beans by growing the stock in any
of the seed-bean-producing areas west of the Mississippi River, since
conditions in such areas are unfavorable for anthracnose development.
Bacterial blights cause water-soaked spots that later throw off a
PEAS AND BEANS 263
gray or yellow exudate depending on the blight involved. Bacterial
blights can be eliminated by growing in dry-land seed-bean areas, or
in certain irrigated districts in Idaho and California.
Mosaic causes a green pattern in the leaf, and in severe cases the
leaves may be distorted and the pods reduced in size. Mosaic spreads
rapidly from one plant to another, and the symptoms often are not
apparent. There is no place known where it is possible to eliminate
mosaic from bean seeds by growing in a special environment.
In some cases organisms in the soil (frequently Fusarium martii
phaseoli Burk.) cause severe injuries to the roots, which may reduce
the stand or result in premature ripening, but such diseases are not
seed-borne.
The relationship of seed-borne diseases to breeding work with
various types of beans can perhaps best be explained by examples.
Previous to the moving of the seed-bean industry to the West, anthrac-
nose was the most serious bean disease. At the present time anthrac-
noso is seldom seen in market-garden or canning varieties of beans
unless the seed has been saved from an eastern-grown crop. On the
other hand, anthracnose is quite common in field beans grown in the
East, since most of the seed must necessarily be home-grown. New
York grows large acreages of both snap and dry-shell beans, of which
the latter are troubled yearly by anthracnose and the former only to a
minor extent. New York State has had a vigorous breeding program in
effect and has originated several strains resistant to various strains of
Colletotrichum lindemuthianum (Sacc. and Magn.) Briosi and Cav.,
the organism that causes anthracnose. There has been no major pro-
gram by any division of the Federal or State institutions to breed
snap bean varieties resistant to anthracnose. Resistance to root-
rotting organisms has been studied, but not much has been done
to breed for resistance against them.
The Newer Bean Varieties
Productions by Private Breeders
In some cases improved strains not possessing any disease resistance
have been introduced. Burpee Stringless Green Pod has been largely
replaced by Landrcth Stringless (about 1927), but the older name has
been retained. The latter undoubtedly was of higher quality, but in
some sections home gardeners object that the seed of the new strain does
not develop quickly enough. On the other hand, quick seed develop-
ment is a characteristic that shippers and most city consumers object to.
Giant Stringless, Full Measure, and Burpee Stringless have been
losing popularity in competition with New Stringless Green Pod
(Tendergreen). This new variety is more resistant to bacterial^ blights
than the other three varieties and yields quite well under a diversity
of conditions. It is said to come from an accidental cross of Stringless
Green Refugee with Full Measure. It was introduced by Henderson in
1922 as Tendergreen, but was pure-lined, renamed, and introduced by
the Associated Seed Growers, Inc., in 1930.
Asgrow Black Valentine Stringless was an introduction by the Asso-
ciated Seed Growers, Inc., in 1930. It is said to come from a cross
of Black Valentine with Pencil Pod Black Wax. It is interesting to
264 YEARBOOK, 1937
note in this connection, however, that some observers have found
white and variegated seeds segregating from this variety. Tins bean
is hardy and of very good quality — in contrast to the poor quality
of Black Valentine — and is replacing the old Black Valentine rapidly
in many shipping sections.
Stringless Green Refugee is very resistant to bacterial blights but
extremely susceptible to common bean mosaic and to many other
viruses infecting beans, as described by Zaumeycr and Wade (95)
and Pierce (SI). In some sections severe economic losses from
common bean mosaic on this variety have occurred.
In spite of the specialized machinery developed for canning beans,
snap bean varieties have remained essentially general-purpose vari-
eties. However, in a few cases canning has tended to intensify the
importance of certain varieties. Stringless Green Refugee lias set a
standard that canners have sought in an early variety. Stringless
Green Refugee is a late, light-green-podded bean, stringless, essentially
free from fiber in the side walls, fine-textured, and with small, straight,
nearly round pods. It has been used mainly for packing whole, but
any oversized pods are excellent for packing as cut beans. Some
canners are not interested in the whole pack and can use a variety
that will produce a large yield of beans of only moderate quality.
In some sections Full Measure is the favorite. It is early, dark-green
podded, stringless, essentially free from fiber hi the side walls, medium
to coarse in texture, with large pods. Where essentially the same
qualities are desired but with lighter pods, Giant Stringless Green
Pod is used. Flat beans are seldom canned. In the wax types a
white-seeded early wax with the quality of Refugee Green is desired.
The nearest approach is Brittle Wax, but canners object to the large
eye, which can sometimes be seen in the processed beans.
Bean Breeding by Public Agencies
The United States Department of Agriculture began breeding work
in 1922 to produce a Refugee type of bean resistant or tolerant 8 to
m'osaic. This work was started by Wilbur Brotherton in cooperation
with the Wisconsin Agricultural Experiment Station and was later
carried on by G. H. Rieman, W. J. Zaumeyer, and the writer. The
first introduction was U. S. No. 1 (1933), an early mosaic-tolerant
strain intermediate in type between Refugee and Full Measure. It
has been favorably received in limited areas only and will probably
remain of minor importance. The second Refugee type introduced
by the Department came in 1935 and is designated U. S. No. 5. All
reports on this bean have been very favorable. It is highly resistant
to common bean mosaic and tolerant to bacterial blight, and the pods
are not distinguishable from Refugee except that those of U. S. No. 5
are free from purple splashing caused by anthocyanin pigment. U. S.
No. 1 is from the tenth generation of a cross of Refugee X Wells Red
Kidney, and U. S. No. 5 is from a cross of U. S. No. 1 with a mosaic-
resistant Refugeo rogue. Previous to the introduction of U. S. No. 1
and U. S. No. 5, Rieman, in cooperation with the Wisconsin station,
« In this discussion the word "tolerant." is used to describe a variety that suffers no appreciable reduction
in yield as a result of infection, although other disease symptoms may be clearly shown. "Resistant" refers
to varieties that are apparently unaffected by the disease in any way.
PEAS AND BEANS 265
had made fairly extensive tests of No. 536 Canning Wax, which did
not prove to be commercially successful but which has since been
used in breeding work for mosaic resistance and for quality of pods.
The Wisconsin station began breeding work with Kefugee X
Corbett Refugee (a rogue type), from which came Wisconsin Refugee
and Idaho Refugee, both introduced in 1934. Wisconsin Refugee is
about the same in season as Stringless Green Refugee. It is mosaic-
resistant, but the type is not so well fixed as Idaho Refugee. Idaho
Refugee is about a week earlier than Stringless Green Refugee. It is
resistant to common bean mosaic and is being favorably received by
the canning trade. The pods carry a slightly heavier purple splashing
in both Wisconsin Refugee and Idaho Refugee than in the parent
varieties, although there is a possibility of eliminating this by further
selection. W. H. Pierce and J. C. Walker introduced these two
strains.
The first bean to be bred especially for mosaic resistance was Ro-
bust. It is a strain of Michigan Pea bean (dry shell) and was intro-
duced by F. A. Spragg, of the Michigan Agricultural Experiment
Station, about 1913 from field selections.
W. H. Pierce and C. W. Hungerford, of the idaho station, intro-
duced Idaho No. 1 Mosaic Resistant Great Northern about 1930.
It is a very hardy dry-shell bean obtained by selection from hetero-
geneous strains of Great Northern.
Further work on resistance to mosaic in snap beans is being carried
on at the Michigan station by C. H. Mahoney and at the New York
stations at Geneva and Ithaca.
One of the most interesting developments in connection with can-
ning string beans is the sudden popularity of a strain of White
Creaseback known in some places as Blue Lake. This is somewhat
different from the ordinary strains of White Creaseback grown in
home gardens. The pods are very long, dark-green in color, and
round in cross section at a very early stage. Nearly all beans canned
from this variety are put up in whole lengths in "asparagus" style.
The popularity of this excellent dark bean may mean the beginning
of a new era in American bean breeding, since the proponents of light-
podded Refugee types can no longer consistently claim that high
quality in a canning bean is associated only with light-green pods.
Bean rust is another problem that has required attention during
the last few years. Kentucky Wonder and most strains of white-
seeded Kentucky Wonder are susceptible to strains of rust. In 1934
L. L. Harter, of the Bureau of Plant Industry, United States Depart-
ment of Agriculture, introduced U. S. No. 3 and U. S. No. 4 strains of
white-seeded, rust-resistant Kentucky Wonder. These were pure-
line selections from heterogeneous strains from Europe known as
World Wonder and Phenomenon, respectively. U. S. No. 3 has been
very favorably received. It is a very early pole bean, coming in
bloom only a few days later than Full Measure. The pods are large,
round, stringless at all stages, and of high quality. U. S. No. 4 is
somewhat later than U. S. No. 3, and the pods are very long, flat,
and stringless in early market stages. They represent an improved
strain of what would ordinarily be considered white-seeded Kentucky
Wonder. Further breeding work is under way involving crosses of
138904°— 3T— 18
266
YEARBOOK, 1937
brown-seeded Kentucky Wonder with U. S. No. 3 and U. S. No. 4
and for resistance to other strains of rusts.
In connection with the bean-breeding program of the Department
several green and wax canning, market-garden, and pole strains re-
sistant to various diseases are now in the course of development.
These are being bred and tested for the most part at Greeley, Colo.,
Charleston, S. C, and Beltsville, Md. Those now engaged in this
work are W. J. Zaumeyer, L. L. Harter, and W. D. Moore in pathology,
and the writer and C. F. Poole in genetics. For the last few years
S. A. Wingard, of the Virginia Agricultural Experiment Station, has
been developing strains of the Kentucky Wonder type suitable for
growing in that State and resistant to rust. He has succeeded in es-
tablishing very satisfactory late strains that are not early enough for
growing seasons in northern or north-central regions.
List of Varietal Introductions
Table 1 shows in a condensed form some of the outstanding bean
varietal introductions of the last 20 years or so.
Taiit.f, ] . — Bean varietal introductions
Variety or strain
Type ! Special characteristics
Introduced by—
Dry shell (pea bean)
Dry shell..
Resistant to common
bean mosaic.
do..
i\ A. Spragg, Michi-
gan, 1913.
Pierce and Hunger-
ford, Idaho, 1930.
Gloyer, 1928.
Do.
Idaho No. 1 Great Northern
Geneva Ked Kidney
York Red Kidney
do
do
Resistant to strains of
anthracnose.
.... do. .
Virginia Kentucky Wonder.
Resistant to rust. _. .
do
do.
Tolerant to mosaic ...
Resistant to mosaic. _ .
do ..
Wingard, 1934.
tr. S. No. 3
U.S. No. 4
U. S. No. 1 .
do
do
Harter, 1934.
Do.
Wade and Zaumeyer,
U. S. Department
of Agriculture, 1933.
Wade and Zaumeyer,
U. S. Department
of Agriculture, 1935.
U. S. No. S
Idaho Eefugee
do
do
Wisconsin Eefugee . .
do
do ..
University of Idaho,
1934.
Kefugee rogue.
do .
University of Wis-
consin, 1934.
Corbett, Sioux City,
Iowa, 1931.
No. 536
Resistant to mosaic,
small pods.
High-quality, dark-
podded canner for
whole-length packs.
Stringiess . .. _
White Creasebaek . . .
Stringiess Valentine. _ .
Department of Agri-
culture and Univer-
sity of Wisconsin.
Clear Lake Canneries
(?), about 1930.
Asgrow Black Valentine. _.
Tolerant to bacterial
blights.
. . do .
ers, 1930.
New Stringiess Green Pod.
do
Landreth Stringiess Green
Burpee Stringiess
Red Valentine
ers, 1930.
Pod.
Stringiess Ked Valentine
The development of new disease-resistant varieties of beans has
done much to stimulate pure-line work among the seed companies,
and many have greatly improved the standards of their basic seed
stocks and of the stocks they deliver to canners and to market and
PEAS AND BEANS 267
home gardeners. The complex nature of present-day breeding work
makes it necessary for seed companies to employ plant breeders with
an adequate knowledge of genetics and plant pathology.
LIMA BEANS
Although the botanical differences between lima beans (Phaseolus
lunatus L.6) and common beans (P. vulgaris) are not great, it has so far
not been possible to cross the two species. The most conspicuous
difference is in the flower bracts. They are small, inconspicuous,
lanceolate, and pointed in P. lunatus and large, conspicuous, and oval
in P. vulgaris.
Lima beans cannot be grown as far north as common beans. In the
South or in the Tropics if a set of blossoms is dropped because of
drought or very hot weather, the long growing season still may give
plenty of time for beans to be set later. Where the seasons are shorter,
failure of the crop may result from the loss of the first blossoms. In
California the long growing season makes it unnecessary for the first
blossoms to develop into pods.
Limas became popular in the United States after 1824, when seed of
the large type — as contrasted with the small-seeded civet or sieva
type — was brought from Lima, Peru, by Capt. John Harris, of the
United States Navy. It was found that the lima did especially well
on the dry lands of southern California. The two limas now most
extensively grown are both dwarf varieties, Henderson Bush and
Fordhook. Henderson Bush was found along a roadside in Virginia
by a Negro laborer about 1885. He sold it to T. W. Wood & Sons, of
Richmond, who later sold the stock to Peter Henderson. It is a small
erect bush type with very small, flat seeds. It can usually be counted
on to produce a crop even under adverse conditions. Wood Prolific
Bush, a later selection from Henderson Bush, is a slightly larger plant.
U. S. No. 2 lima (1933) is a selection from Henderson Bush developed
especially for uniform maturity of the pods on the individual vine.
It is not distinct enough to constitute a variety, but under some con-
ditions it may be from a few days to 2 weeks earlier than most strains
of Henderson Bush. Henderson Bush and related types are grown to
some extent in home gardens but are more generally used for commer-
cial canning.
Canners have wished to combine the hardiness and yield of Hender-
son with the quality of Fordhook. In 1934 the McCrea Seed Co. in-
troduced the McCrea lima, which is green-seeded when mature, of
high quality, but late and not an especially good yielder in eastern
canning districts. The green seed character is not apparent in either
Henderson or Fordhook, so it is probable that the parentage is some
large, green-seeded variety crossed with Henderson.
Fordhook, a large-seeded dwarf plant, was discovered in a field
of Challenger pole limas by Henry Fish, of Santa Barbara, Calif., in
1903. Burpee introduced it in 1907. It is now the favorite market-
garden variety. A small quantity is canned, but its popularity for
canning has not been great because of its sensitiveness to adverse
weather conditions.
Gin ordinary botanical usage Phaseolus lunatus is the ciyet or sieva bean and P. lunatus macrocarpits
Benth. the lima bean.
268 YEARBOOK, 1937
During the last several years the California Agricultural Experiment
Station has introduced strains of a very hardy, high-yielding, small-
seeded lima known as Hopi, selected by Mackie from limas grown by
the Hopi Indians. Most of the Hopi and Henderson Bush grown
in California are used as dry, edible beans.
A very noteworthy fact about lima bean breeding is that prac-
tically all varieties have arisen by selection and very few from con-
trolled breeding work. Roy Magruder, of the Bureau of Plant
Industry, is at the present time carrying on considerable breeding
and genetic work involving seed-coat colors, seed sizes, and the
breeding of various types for canning.
In the southern United States pole limas with either colored or white
seeds are grown extensively in home gardens and to some extent for
marketing under the name of butter beans. These are very hardy
varieties and probably offer worth-while breeding material for crossing
with nonhardy, high-quality varieties such as Fordhook.
GENETICS OF PEAS AND BEANS 7
Peas
The many stable forms of Pisum sativum early attracted the attention
of those interested in theoretical scientific work as well as the atten-
tion of many breeders. It was with garden peas that Gregor Mendel
in 1856 began his historic experiment, which laid the foundation for
genetic science. His findings were made public in 1865 but attracted
no attention until they were rediscovered by Correns, De Vries, and
Tschermak independently in 1900.
Mendel worked with seven different factors: Yellow v. green
cotyledons, smooth v. wrinkled seed coats, normal v. fasciated stems,
tall v. dwarf growth habit, green v. yellow pods, parchmented v.
nonparchmented pods, and the pleitropic factor for colored v. colorless
seed coats, colored v. colorless leaf axils, and purple v. white flowers.
A pleitropic factor is one that affects many different characters.
In spite of Mendel's success with the plant, peas have not proved
to be ideal for genetic studies, and consequently most of the funda-
mental contributions since his time have been with organisms other
than peas. There are probably several reasons for this: (1) Many
single-factor differences frequently show wide divergences from a
3:1 ratio. (2) Linkage values may vary sharply from one cross to
another. (3) Different classification of phenotypes gives rise to
reports of more than 50 percent crossing over. (4) The number of
independent factors and groups of factors appears to exceed the
number of chromosomes. (5) Peas have proved to be rather difficult
material for cytological studies.
Wellensiek (85) brought the available data up to date and has
worked unceasingly to eliminate conflicts in designations of various
factors. Matsuura (39) also reviewed and tabulated the literature
dealing with Pisum genetics. The following lists of factors are taken
largely from Wellensiek, with a few modifications by De Haan (11)
and Winge (92). _ The number of genes listed is 68, but the known
number may be in excess of this. In some cases it has been difficult
' This section is written primarily for students or others professionally interested in breeding or genetics.
PEAS AND BEANS 269
to decide whether some ratios are the result of pleitropic effects of a
single gene or the effect of several genes completely linked. Winge
gives a table showing certain gene designations made by himself and
10 other authors, including De Winton (98), Wellensiek (86, 87, 88,
89, 90), Rasmusson (55, 57, 58), White (91), Lamprecht (SO), Pellew
and Sverdrup (49), Sverdrup (70), Nilsson (42), Kajanus (21, 22), H.
and O. Tedin (72, 73), and De Haan (11).
Pisum Factors
A. Basic gene for anthocyanin color of the flower. It also influences indenting
of seeds, seed-coat color, marbling of seed coat (except ghost marbling) , leaf-
axil color, violet and red pod colors.
A\, crypto purple; Ait purple dotted flowers; a, white.
Ar. Gone for reddening, salmon-pink flowers.
Ap. Apple blossom.
Am. Pinkish-white flowers.
B. Gene for bluing.
Bl, basic gene for wax or bloom; bl, waxless (emerald).
Bta, blunt apex; bta, acute apex.lBoth recessives must be present in homozygous
Btb, blunt apex; bib, acute apex./ condition to produce acute.
Cp, curved podj cp, straight.
Cr. Changes crimson to purple in presence of A. (Fedotov (7).)
Cv. Intensifies anthocyanin color in presence of A and B. (Fedotov (7).)
Cm. Cream flowers. (Fedotov (7).)
Em ', Em 2, normal; em1, em2, emergences if both are present.
^Z 'JThickness of seed coat. (Kaznowski (23) .)
Dw, D, d. Leaf axil ring double, single, absent. (Tedin and Tedin (72).)
F. Purple dotting of seed coat I. (Wellensiek.)
F3. Purple dotting of seed coat II. (Winge.)
Fe, normal pods, fertile; fe, split pods, sterile as female. (Sverdrup (70) .)
Fa, normal stem; fa, fasciated stem.
Fu, resistant to fusarium wilt; fu, susceptible.
Fl, gray spotting on leaves; fl, green leaves.
Fn, one or two flowers per peduncle; /«, three or more flowers per peduncle.
G, green cotyledon; g, yellow cotyledon. (Nilsson U#).)
Gp, green pod; gp, canary yellow pod.
H. With A gives orange seed coat.
I. Inhibits action of G, giving dominant yellow cotyledons.
If, intermediate flowering; if, early flowering.
J. In presence of A, causes dark-brown seed coat.
K, normal wings; k, keeled wings.
Kl. Inhibits coupling between A and Gp. (Hammarlund (18).)
L, L\, -L2. Genes for wrinkling or dimpling of seed.
Le, Le\, le. Long, very long, and short internodes.
La. Growth-inhibiting factor. (De Haan (It).)
Lb. Growth-inhibiting factor.
Lc. Growth-inhibiting factor.
Ld. Growth-inhibiting factor.
(Le dominates if La or Lb is present, biit not if the two recessives, la, lb,
are present. Either Le, la, lb, or le, la, lb is slender. 45: 15: 4 segregation
of tall, short, slender in F2.)
Lf. Retards flowering time caused by //; ineffective by itself.
Lo, Lo,, Lo2, Lo3. Genes for seed length. (Kaznowski (US).)
M with Z gives "ghost marbling" of testa; with both A and Z, brown marbling.
Mi to MA. Genes for susceptibility to mildew. (Hammarlund (IS).)
Mp. Rusty radicula. (Tedin and Tedin (73).)
N, thin pod wall; n, thick pod wall.
Nr, normal; nr, narrow rogues. (Pellew (48).)
0, or, oy. Green, lemon, gold pods, stems, and foliage.
Oh. Inhibits the expression of red, converts red to bright-brown seed coat.
P. Thin parchmonted membrane in pod; p, no membrane.
270 YEARBOOK, 1937
P1' Purolc Dod II fl*°*h dominants necessary to make pod purple.
Pa, green pods; pa, pale pods.
Pe, normal pods; pe, pearl pods.
PI, dark hilum; pi, light hilum.
Pt. Quick growth of pollen tube.
<?, aborted seed; q, normal seed. (Wellcnsiek and Kcyser (00).)
R, round seed; r, wrinkled seed surface.
(R is hypostatic to A; r is epistatic to A. In conjunction with genes Li
and L2 of Hadficld and Caldcr (IS), the following forms may be distin-
guished: Smooth, lx li l2 12 RR; dimpled, Li Lt L2 L2 RR; wrinkled, Lx L\ L2
L2 rr; wrinkled, li h L2 L2 rr).
Re, normal leaves; re; reduced leaves.
S, seeds free in pod; s, seeds clinging together (chenille or brochette).
Sa.it Sa2, Sfia- Genes for number of stomata. (Tavcar (71).)
Sgi to Sgt. Genes for seed weight.
Snj, intermediate value for node number; swi, low value.
Sn2, increases the value for node number caused by fin,; ineffective alone.
St, normal stipules; si, reduced stipules.
T, Ti, T2. Genes for internode number.
Td, leaves dentate; td, leaves not dentate.
Tl, tcntril leaves; tl, acacia (no tendrils).
U, violet seed coat.
Uni, Normal leaf; uni, unifoliate.
V, Strong membrane in pod; v, thin membrane.
Wb\. Strengthening gene for wax.
WT>2. Strengthening gene for wax.
W2, green foliage; w2, white variegated.
X. Stipule size. (Brotherton (1).)
Y. Stipule size.
Z, colored seed coat; z, uncolored seed coat.
As there are many factors influencing flower color, it is perhaps
best to illustrate the genetic constitution of some of the many colors
that occur. These are given from Dc Haan (11):
Purple A A Ar Ar B B Ap Ap Am Am
Violet A A ar ar B B Ap Ap Am Am
Rose A A Ar Ar b b Ap Ap Am Am
Light purple A A ar ar b b Ap Ap Am Am
Apple blossom A A Ar Ar B B ap ap Am Am
Apple rose A A Ar Ar b b ap ap Am Am
Apple violet A A ar ar B B ap ap Am Am
Pinkish white A A Ar Ar B B Ap Ap am am
White a a Ar Ar B B Ap Ap Am Am
A cross of violet by apple rose results in a purple Fi with a trihybrid
ratio in F2 of 27 purple : 9 violet : 9 apple blossom : 9 rose : 3 apple
violet : 3 apple rose : 3 light purple : 1 expected to have an appearance
between apple rose and light purple. According to the above scheme,
all those having aa arc white regardless of the rest of the genetic
constitution. A certain white8 X apple blossom results in an F2 segre-
gation of 9 purple : 3 apple blossom : 4 white. According to the
designations of Fcdotov (7) , Cm can produce a cream flower and it
is independent of the action of A.
In addition to flower color, the genes that have been listed have an
influence on color of the leaf axil. Purple and apple-rose flowers are
associated with purple axils; pinkish white, with dull-rose axils; violet
and apple violet, with violet; rose and apple rose, with rose; and light
purple, with light purple. Dw produces a two-ring effect in the
axils, D a single ring, and d no ring.
8 Only tho white of the constitution aaArArBBApApAmAm will give the ratio cited when crossed with
applo rose.
PEAS AND BEANS 271
There is considerable variation in the amount of waxiness or bloom
on peas. Waxiness is caused by a gene for wax Bl, and is intensified
by the presence of either W\ or Wb2 or both.
Two genes (6ia and btb) must be present in the homozygous condi-
tion for a pod to have an acute apex. Crosses between strains with
blunt pods and those with sharp result in the F2 either in a ratio of 15
blunt : 1 acute or of 3 : 1, depending on how many of the genes for
bluntness were present in the blunt parent. There is at least one
other factor influencing pod-apex shape.
The genefe is responsible for a rather peculiar condition in which
the developing pods split along the dorsal suture, resulting in the
death of the developing seeds.
The fasciated or flattened stem condition is due to a recessive gene,
fa. This flattened condition results in a terminal inflorescence that
superficially resembles an umbel. Some flower stalks may produce
from three to seven flowers, while others produce only one or two on
the same plant.
Tallness and shortness in pea plants have long been of much
interest, and it has been discovered that many factors are concerned
with stem length. In some cases simple 3 : 1 ratios of tall to short
are obtained in the F2 generations from crosses of tall with short.
In one such cross, however, De Haan (11) obtained an F2 seg-
regation of 45 tall : 15 short : 4 slender. Two recessive genes
must be present to produce a slender plant. Gene Le is epistatic to
La or Lb but hypostatic to la or lb. Genes le and Id result in a slightly
larger short plant designated "short 2." One of the factors for slender
is identical with le or Id, but it has not yet been determined which.
The edible-podded condition (no membrane) is determined by the
recessive gene p in the homozygous condition. The factor V results
in a very strong membrane when acting in conjunction with P.
Pt is a theoretical gene for quick growth of the pollen tube. Its
presence has never been determined by actual ratios.
Round seeds are dominant to wrinkled, and segregation is by
individual seeds. Several genes influence the condition known as
indenting or dimpling, and segregation is by plant. A three-factor
explanation has recently been given (12) of the conditions designated
smooth, dimpled, and wrinkled, respectively.
Seed weight is influenced by several factors, the exact number of
which has never been determined. Violet flower is sometimes asso-
ciated with abnormal hilum, which results in low seed weights on
plants having violet flowers. Many other factors also probably
influence seed weights.
The Gradus rogue (rabbit ear) character (1) is a rather unique
condition in which very rapid mutation of the recessive gene x for
normal Gradus type to the dominant X (rogue) occurs when these
genes are associated together in a cross. While other factors involved
in a cross may be segregating as expected, no plants of normal type
may be recovered in F2 or subsequent generations.
Seed-coat colore are also affected by the gene A for anthocyanin.
Factors Ar and B have an effect on seed-coat color parallel with their
272
YEARBOOK, 1937
effects on flower color, but Am and Ap have no effect on seed coat.
The effects of PI, M, F, Oh, Z, and Mp on flower color are known.
Disease Resistance
Hammarlund (18) reported that immunity of peas to powdery mil-
dew was due to the presence of four genes, Mx, M2, M3, and M4. The
varieties commonly grown in the United States are all susceptible to
powdery mildew, but artificial control methods have been effective in
preventing damage by this organism. Neither genetic nor breeding
investigations of powdery mildew resistance have been undertaken in
this country.
Wade (82) reported that resistance to fusarium wilt of peas was due
to a single dominant gene, Fu. This was slightly linked with Le.
Extensive breeding work has been carried out by many workers, and
|— 42 >!«-
42 •
36
DP2
ife.
47
Mp
St P,
16
3.2 2?
30
-32-
50-
-42-
26-
-35-
-45
-36-
2[
V Le
BTa
Pe
PI Fl
r i4 '
34 19
33
5.5|
3C
[- — 22
-16 — H
Cp Q
1
14
PaBtfa
]
|»— 25 — 4
Oh Ar Bl
I-H6-H
P.TI
7UB
8
Gp
42
41 7.3' 12 I 5 I °.9 »Z ' I 6 I ' '8 ' I
Figure I. — Linkage groups in Pisum. (Af ler Winge.)
at the present time all the canning varieties are available in wilt-
resistant forms.
Zaumcyer and Wade (96) have shown that different varieties of peas
show differential reactions to various types of legume mosaics. The
presence of many diseases, frequently epidemic in nature, indicates
that in the future much work will be done in connection with the in-
heritance and breeding of disease-resistant strains of peas.
Various reports have shown that many varieties of peas possess some
tolerance to the attacks of various root-rotting organisms, but the
genetic bases of these reactions have not been determined.
Linkage and Cytology
The contribution of Winge (92) on linkage in Pisum has greatly
clarified the linkage situation. lie describes eight linkage groups,
which are here redrawn (fig. 1) from his publication.
It is believed that further research will eventually reduce the number
of linkage groups to seven, to correspond with the number of pairs of
chromosomes known to be present in. Pisum sativum.
Ring formation (9) seems to be the most satisfactory explanation of
many of the variable linkage results obtained by Rasmusson, Wellen-
PEAS AND BEANS 273
siek, Tedin and Tedin, and other workers. Although Rasmusson (56)
shows the genetic nature of some linkage intensities, the number of
factors involved in the segregation of these intensities is not known.
Hakansson (10) reports a semistcrile condition in association with
chromosomal exchange. Sutton (69) reports an instance of half
disjunction in a case involving four chromosomes.
Beans
The literature on bean (Phaseolus vulgaris) genetics and breeding is
very extensive. Kooiman. (24) presents a very thorough review of the
subject and does much to clarify conflicts in terminology. Doornkaat-
Koolman (4) had previously reviewed the literature, especially that
dealing with disease resistance. Matsuura (89) also presents a sum-
mary. Much of the material in this paper is drawn from reviews by
these authors, with stress on literature published since 1929.
Inheritance in beans has been investigated for a long time, but
there are still many divergent results that need further studies for
adequate interpretation. This is especially true with regard to flower
colors and their relationship to seed and pod colors.
Shaw (66) and Shaw and Norton (67) present extensive observa-
tions on flower colors, which indicate that at least two factors must
interact for the production of pigment in flowers. According to their
observations, most varieties with pigmented seeds, with the exception
of Red Valentine, have colored flowers. However, many other excep-
tions to the observations of these authors are now known.
Johannsen (19) obtained a dihybrid ratio in progeny from a cross
of a white-flowered brown-seeded bean variety with a violet-flowered
black-seeded one.
Tjebbes and Kooiman (76) explain the results of a spontaneous cross
of violet X lilac-flowered, in which dark violet, light violet, lilac, and
white flowers appeared in association with red and blue pods and
various seed colors on the basis of three genes. B causes red pod strip-
ing whether or not the ground factor A for seed-coat color is present.
When A is present the flowers are lilac; the seed coat is red, due to E.
Bl changes these colors to bluish tints. Heterozygous Bl bl results in
light violet. They assumed a total of seven genes for flower color.
Kooiman (24) suggested an eight-factor explanation of the various
seed-coat colors encountered.
Sirks (68) presented a factorial explanation of various seed-coat
colors and summarized the literature up to that date.
Lamprecht (25, 26, 27, 28, 29, 81 , 82, 83, 84, 85) has presented a
very satisfactory explanation of most of the seed-coat colors encoun-
tered in beans. He assumes eight pairs of genes and the following
interactions among them:
P. Basic color factor, in itself producing no color.
C with P gives sulphur white; Cc, mottled.
J. Pale ecru in seed coat, also in hilum.
G with PCJB gives mineral brown; with PCJV gives maroon brown; with PCJBV
gives black; with Ca gives caruncle streak.
B with PCJG gives mineral brown; when heterozygous with PCJVv gives dark
dull green; when homozygous with PCJV or PCJVG gives black.
V with PCJG gives maroon brown; when heterozygous with PCJBb gives dark
dull green; when homozygous with PCJB or PCJBG gives black.
274 YEARBOOK, 1937
R. Red.
Ca. Caruncle streak; shows only in presence of G.
PCJ. Chamois color.
PCJG. Blister (yellowish brown) .
PCJgB. Golden bronze yellow.
PCJgbV. Violet purple.
PCJGB. Mineral brown.
PCJGV. Maroon brown.
(Chamois, PCJ, in the presence G and B gives mineral brown; G and
V give maroon brown; B and V, both heterozygous, produce dark dull
green; while B and V, either homozygous or in the presence of G, produce
blank.1)
PCJBbVv. Dark, dull green.
PCJBVG. Black.
Micropyle streak is recessive and will not show in the presence of
either or both inhibiting factors Mi and Mia; furthermore, J is nec-
essary for its expression even when the inhibitors are absent.
Later, Lamprecht (88) has shown that factors J and B are inherited
independently, and that in addition to the Cc inconstant marbling
there is also Br inconstant marbling.
Schreiber (64, 65) explains his results on a somewhat different
basis. Genes Mi and M2 must both be present to produce a constant
marbling effect. B is a factor for light brown; C is an intensilier.
D is for dark green, effective only in the presence of the bas? -• color
factor A or P. L inhibits partial spotting caused by Shaw and
Norton's "T". Miyake, Imai, and Tabuchi (41) found all seed-
coat colors hypostatic to black.
Tschermak (78) suggested two genes for eye pattern:
(1) ziz1Z2Z2. Seeds having half or more of the testa pigmented with sharp limits.
(2) Z\Z\Z\Z2. Seeds having half or less pigmented, without sharp limits.
(3) z\Ziz2z2. Pigment confined to a small hilum spot.
Sax (60) found in his crosses of two types of Yellow Eye beans that
the heterozygous condition resulted in a pigmented area exceeding
twice that of the parents. Only a single gene was involved.
Currence (8) found two distinct types of bean pod stringiness, one
due to two dominant complementary genes, the other to an incom-
pletely dominant gene for stringlessness with an inhibiting factor.
Joosten (20) distinguished 10 classes of stringiness. Prakken (58)
found 15 stringless to 1 stringy in an F2 generation.
Tschermak (78) observed 3 : 1 and 13 :3 ratios in F2 for nonconstricted
versus constricted pod. Lamprecht (26) interpreted his results on the
basis of four factors.
Emerson (5), Lock (86), Doornkaat-Koolman (4), and Tschermak
(79) found green pods dominant over yellow (wax) with a 3 : 1 ratio in
F2. Currence (8) found two factors to determine the difference between
these characters.
Tschermak (79) found a single factor difference between round
versus fiat, with round dominant. W6.ycicki (94) and Currence (3)
found several factors involved.
Miyake, Imai, and Tabuchi (41) have studied the inheritance of
color of stem. Two types of green crossed together gave a red F1(
followed by a segregation of 9 red : 7 green in F2. Pink x green gave
9 red : 3 pink : 4 green.
PEAS AND BEANS
275
Emerson (5, 6) shows that there are three factors involved in bean
height: (1) Determinate versus indeterminate growth; (2) number of
internodes (in pole beans this depends largely on environmental con-
ditions); (3) internode length.
Norton (45) interprets his results by means of three factors govern-
ing height:
A-a. Indeterminate v. determinate.
L-l. Tall v. short.
T—t. Twining v. nontwining.
ALT. Pole beans.
ALL Runner beans, nontwining polo.
Alt. Shoots from main axis short; some few early, twining shoots.
aLT and aLt. Spreading forms with long branches.
alT and alt. Erect, bush.
Three-to-one segregations of tall to short have been observed by
McRostie (87), Tjebbes and Kooiman (76), and Doornkaat-Kool-
man (4).
Table 2 gives some bean characters not considered above.
Table 2. — Bean characters
Contrasted characters
Blunt v. sharp leaf apex
Broad v. narrow leaf
Long v. short internode
Nonparchmented v. parchmeuted pod.
Threshable v. difficult to thresh..
Yellow ti. green cotyledon
Yellow v. chamois seed ...
Straight v. curved pods
Round v. elliptical pods
Normal v. umfoliate leaves
Partially colored seeds
Unlimited v. limited growth ot axil
Unbranched v. branched inflorescence.
Ir2 segregation
3:1
Complex.
do— .
3:1
3:1
3:1...
3:1
3:1 and 2 modifying
factors.
3:1 and bifactorial...
3:1
4 or 5 genes..
3:1
3:1...
Author
Tschermak (78).
Emerson (5), Wdyclcki (94).
Tschermak (78), Woycicki (94).
Emerson (S), Tschermak (78), Wei-
lensiek (S4).
Tjebbes and Kooiman (76) .
Tschermak (?«).
Kilssou (43).
Lamprecht (M) .
Do.
Lamprecht (3-5) .
Lamprecht (SI ) .
Lamprecht (34) .
Do.
Disease Resistance
Several strains are known of the organism Colletotrichum lindemuthi-
anum, causing bean anthracnose. Burkholder (2) and McRostie
(37, 38) have studied the inheritance of resistance. Where one strain
of fungus was concerned, a ratio of 3 resistant to 1 susceptible was
obtained; two strains resulted in a 9:7 ratio. Further work is being
done on this problem at Cornell University and in the United States
Department of Agriculture.
Schreibcr (64) indicates that there are three independent factors for
resistance corresponding to three anthracnose strains.
McRostie (38) in crosses involving Robust Pea bean X Flat
Marrow observed the Fx showing a partial dominance of susceptibility.
F2 indicated at least a two-factor difference. Pierce (52) and Parker
(47) have studied the inheritance of resistance to common bean
mosaic, using different bean varieties. Parker concluded that since
reciprocal crosses gave different results, at least part of the material
for resistance was carried in the plant outside the chromosomes.
Pierce did not attempt to show a genetic interpretation.
It is interesting to note in connection with the maternal inheritance
suggested above that Hoffman (16) found that modifications persisted
276 YEARBOOK, 1937
for six generations after he had treated navy beans with chloral
hydrate. These modifications were transmitted only by the cyto-
plasm of the egg cells and not through the chromatin. It is also of
interest to note that Parker (46) has fo\md an undoubted case of
maternal inheritance of leaf variegation.
Zaumeyer and Wade (95) and Pierce (51) have indicated that more
than one strain of bean mosaic or of legume viruses transmissable to
beans are in existence and that bean varieties differ in their reactions
to them. Genetic studies of varieties resistant to the viruses are
now in progress in the Department.
Rands and Brotherton (54) tested the resistance of many vaiieties
and strains of American and foreign beans to several diseases, including
at least three strains of the anthracnose organism, bacterial blight, bac-
terial wilt, and mosaic, and found differential reactions in some cases.
Fromme and Wingard (8) made a report on resistance and sus-
ceptibility of various bean varieties to rust. There is much material
available for genetic and breeding studies in connection with this
disease.
McRostie (38) made some observations on the inheritance of re-
sistance to dry root rot of beans, caused by Fusarium martii phaseoli,
but he did not attempt to give a factorial explanation of his results.
Crossing Technique and Interspecific Hybridization
Beans are somewhat difficult to cross, since the curled and brittle
style of the flower is easily broken during the process of opening the
keel. If the atmosphere is kept near the saturation point for a few
days after artificial pollination has been effected, the chances for suc-
cess are much better than in only a moderately moist atmosphere.
The time required to make crosses has prevented genetic studies in
Phaseolus involving backcrosses.
Many attempts have been made to secure interspecific hybrids
within Phaseolus, mostly without success except for that involving
P. vulgaris and P. multiflorus. In such hybrids there is usually a
great deal of sterility and variability in results, even in the Ft.
Mendel (40), Doornkaat-Koolman (4), Tschermak (78), and Tjebbes
(74) have made studies involving this interspecific cross. At the
present time the United States Regional Vegetable Breeding Labora-
tory, near Charleston, S. C, is testing a variety from Mexico that
arose from the cross of P. vulgaris with P. multiflorus.
Linkage and Cytology
Weinstein (83) has shown that Phaseolus vulgaris and all other
species of Phaseolus have 11 pairs of chromosomes!
Tjebbes (75) recognizes two linkage groups. Linkage in the
B-A-R-S group is very close, showing a cross-over value of less than
1 percent between B and S. S is a factor for striping and the other
three factors influence the seed-coat color. Genes C and 6 are in
another group with a cross-over value of about 35 percent.
Several factors give pleitropic effects or the effects are in reality
due to more than one factor. However, in such cases it usually re-
quires extensive work to establish the nature of the gene or the close-
ness of the linkage involved.
PEAS AND BEANS 277
Sax (60, 61, 62, 63) attempted to analyze quantitative characters
by studying their linkage relations to qualitative genes. lie demon-
strated at least five cases of linkage.
Lima Beans
Only a very limited amount of genetic work has been done with the
lima bean (Phaseolus lunatus L.). Rhind (59) reports genetic studies
involving three factors, which he designates as —
jK. Rosq color seed coat. S. Speckled seed coat.
P. Intensifies rose to purple seed coat.
lioy Magruder, of the Bureau of Plant Industry, is carrying on
genetic studies with Phaseolus lunatus.
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1927. GENETISCHE STUDIEN UBER DIE HULSENFORMEN BEI DEN BOHNEN.
Acta Soc. Bot. Polon. 5: [20J-51, illus. [In Polish. German
summary, pp. 48-51.]
(95) Zaumeyer, W. J., and Wade, B. L.
1935. THE RELATIONSHIP OP CERTAIN LEGUME MOSAICS TO BEAN. Jour.
Agr. Research 51: 715-749, illus.
(96) ■ and Wade, B. L.
1936. PEA MOSAIC AND ITS RELATION TO OTHER LEGUME MOSAIC VIRUSES.
Jour. Agr. Research 53: 161-185, illus.
IMPROVEMENT IN THE LEAFY
CRUCIFEROUS VEGETABLES
ROY MAGRUDER, Olericullurist, Di-
vision of Fruit and Vegetable Crops and
Diseases, Hurcau of Plant Industry
ACCORDING to most botanists, cabbage, cauliflower, broccoli,
green-sprouting broccoli, brussels sprouts, kale, collards, and kohlrabi
are very closely related, being horticultural forms of the species
Brassica oleracea L. Kohlrabi is assigned by some botanists to
B. caulorapa (DC.) Pasq. "Wild cabbage (B. oleracea), illustrated in
figure 1, from which all these forms or varieties are supposed to have
arisen, is still found growing wild along coastal regions of Europe and
northern Africa. Its use by man as food antedates written history,
and it is believed to
have boon in rather
common use for more
than 4,000 years.
Just when or where
the various forms or va-
rieties of cabbage first
appeared or were de-
veloped it is difficult to
say with any degree of
certainty because of the
lack of written records.
Kale and collards (var.
rirhl'is L.) are probably
the oldest type, and
the present wrinkled or
ruffled type was men-
tioned byTheophrastus
in 350 B. C. and described and illustrated by Dodonaeus in 1559. Red
cabbage or kale was also known to Theophrastus, and Pliny describes
heading cabbage (var. capitata L.) and includes in his list of types a
savoyed or blistered-leaf type which is thought to be the ancestor of our
present savoy cabbages. The name savoy indicates that much of the
early developmental work occurred in the locality of Savoy in southeast-
ern France. Cauliflower and broccoli (var. botrytis L.) are believed to
be more recent additions to our types and to have been developed from
the green-sprouting broccoli. Kohlrabi (Brassica oleracea var. gongy-
lodes L., or, if considered a species, B. caulorapa) probably was brought
north to the low coastal countries of Europe by way of Prague and
Vienna. The two most important varieties of today are White
Vienna and Purple Vienna. Brussels sprouts (var. gemmifera DC.)
283
Figure I. — A wild cabbage plant.
284 YEARBOOK, 1937
were not mentioned by the early writers prior to 1759, but by 1793
this vegetable was an article of international commerce, and its origin
is generally ascribed to Belgium.
THE PART PLAYED BY SEEDSMEN IN THE
DEVELOPMENT OF CABBAGE
Varieties of vegetables as we speak of them today in our seed cata-
logs hardly existed before the last of the eighteenth century either in
the United States or in Europe. This date corresponds with the rapid
rise of seed growing as a business venture in Europe, and no doubt the
competition between seedsmen for something new to offer their cus-
tomers was, then as now, the incentive that led to the rapid intro-
duction of varieties.
The early named varieties were groups of plants with a few common
characteristics but many variations. The more observant, careful,
and critical growers were always looking for improvements, and when
plants were found that seemed superior, these were selected for seed
propagation. By continued selection of superior or distinctive types
suitable to the particular locality in which the grower lived, many
local strains or horticultural varieties — as distinct from botanical
varieties — were developed. The local seed seller disposed of any
surplus the grower might have, and, as the industry developed, an
opportunity was afforded for the general distribution and trial of
many varieties over a wide range of conditions. If the variety per-
formed well in its new location, it soon attained major importance.
If it was unsuitable in general yet possessed some special merit, it
probably was the starting point for a new variety, which was developed
as the result of continued selection for the especial point of merit.
Thus the early development of all our crops was the work of observant
and critical growers who through superior skill in selection and seed
growing gradually became the local sources of superior seed. The
early seedsmen were merchants, not growers or breeders of seed.
A SINGLE piece of publicly supported plant breeding saved the
cabbage-growing industry in many sections of the country and
brought an enormous return on the cost. This was the work begun
in Wisconsin in 1910 by L. R. Jones, and continued through the
cooperation of J. C. Walker and his associates of the United States
Department of Agriculture, to develop varieties resistant to the
devastating cabbage yellows or fusarium wilt. As a result, there
are now yellows -resistant varieties of all the major types of cabbage
demanded by the market. Today other diseases are receiving the
attention of breeders, as well as the problem of adaptation of vari-
eties to definite regions and the development of types superior in
eating quality and in ability to hold up well in storage.
CABBAGE, ETC. 285
The types or varieties of cabbage were developed mainly by the
people of the Netherlands, Denmark, Germany, France, and England.
When brought to this country by the early settlers, they were not
always suited to our climate, which generally was hotter and drier
than the climate of the north European countries. The uncertainty
of supply and the cost of imported seed forced the isolated grower to
attempt to produce seed for himself. Starting with imported seed, he
proceeded to select the individual plants that best suited his needs
and grow seed from them. If he wanted something earlier maftiring,
later maturing, with less outer leaves, more rounded head shape,
smaller size, more heat-resistance, or what not, he selected toward
that goal and in many instances was successful.
The enterprising mail-order seed dealer was largely responsible
for the location and introduction to the public of many of these locally
developed strains, sometimes with the growers' name affixed but
many times with a name selected by the introducer. The high prices
paid for these types stimulated seed growers in their effort to find
new and superior varieties or strains. Some of the growers soon found
they could make more money by growing seed than from the market
crop and devoted their energies to seed production. Most of the
early cabbage-seed growers were located on Long Island, N. Y.,
because of the favorable growing conditions there.
At the beginning of the nineteenth century most of the cabbage
grown on Long Island belonged to three types: Early York, an early
maturing variety with elliptical heads ; Flat Dutch, a large midseason
variety with flat heads; and Red Dutch, a late, hard, round-headed
Variety. The Flat Dutch type was more productive and in greater
demand on the market than the other two types, and most of the
American varieties or strains introduced during the nineteenth century
were selections from the Flat Dutch type. An objective of major
importance to all growers of cabbage was that every plant should
produce a marketable head, and this characteristic is emphasized in
the names of some of such varieties as All Head and Surehead.
Selections were also made for earlier and later maturing strains of
the Flat Dutch type in order to extend the marketing season over a
longer period. Some of these selections for difference in maturity
resulted in differences in head shape and size and in a rather wide
range in type when compared with the parent variety. The early
growers were also interested in securing cabbages resistant to disease,
and the Houser and Bugner varieties are the results of the efforts
of two men along this line. As the seed business became more highly
competitive and the growers more critical, the matter of attaining
uniformity of type became an object of considerable attention and
effort. At the present time there are available very uniform stocks
of varieties that cover the entire range of season of maturity and are
satisfactory in head size and shape.
A list of the cabbage varieties of known American origin with the
year of introduction and other information is given in table 1.
It is also of interest to note which of our present-day important
varieties are foreign introductions. In the list of what may be
regarded as the nine principal American varieties of cabbage we find
Early Jersey Wakefield, Copenhagen Market, Early Winningstadt,
286
YEARBOOK, 193 7
Glory of Enkhuizen, Late Flat Dutch, and Danish Ballhead to be the
names of orginal importations, although the present strains of the
first and of the last two varieties show a decided improvement in
uniformity of type, which may be attributed in part at least to the
efforts of American seedsmen. Other varieties of lesser importance
that are known to be importations by American seedsmen are Golden
Acre, Resistant Detroit, Early York, San Francisco Market, Volga or
Early Stonehead, and almost all of the red and savoy varieties.
Table 1 . — Cabbage varieties of known American origin
Variety name
Producer
How pro-
duced
Parental variety
Introducer
Year
intro-
duced
All Head Early
Mr. Strong, Long
Island, N. Y.
Mr. Vandergaw,
Long Island, N.
Y.
John Bugner, Prai-
rie View, 111.
John M. Brill,
Hempstead, N.
Y, or Francis
Brill, Eiverhead,
N. Y.
D. M. Ferry & Co~
John Fottler, Eos-
bury, Mass.
George Houser,
Harrisburg, Pa.
TJnknowD
Father of Francis
Brill
Abraham Van Sec-
len, Jamaica, N.
Y.
John Mason, Mar-
blebead, Mass.
John Stone, Mar-
blehead, Mass.
Unknown. .. ._
Ferrv-Morse Seed
Co.
Gill Bros. Seed Co.
Joseph Harris & Co.
D. M. Ferry Seed
Co.
Selection
do
Flat Dutch
do ..
W. Atlee Burpee
& Co.
James J. II. Greg-
ory.
1891.
1886.
Vandergaw).
Cross and
selection.
Selection
do.
do _
do
Cross and
selection.
do
Selection
do
do
do
do
do
do
do
Unknown
Jersey Wakefield..
Danish Ballhead—
Frucker Braun-
schweiger.
Stein's Flat
Dutch.
Fottler's Bruns-
wick X Short
Stemmed Dan-
ish Round.
French Ox Heart
X Large Flat
Dutch.
Early Summer
Scotch Drumhead .
Mason
Wonderful).
Charleston or Large
Wakefield.
Ferry's Hollander..
Fottler's Early
Drumhead . or
Brunswick Short
Stem.
F. W. Bolgiano &
Co.
D. M. Ferry &
Co.
A. Schlegel
Holmes Seed Co. .
1890.
About
1866.
1900.
1866.
1897.
tor Flat Dutch.
Newark Early Flat
Dutch, Early
Flat Dutch, or
Early Summer.
do
Peter Henderson
&Co.
1900.
Before
1880.
1888.
Stone Mason
do
do .
1863.
Do.
can Savoy.
Ferry's Round
Dutch.
Gill's Oregon Ball-
head.
Harris' Railhead
Midseason Market-
Early Dwarf
Dutch.
Danish Ballhead--
do
Low Late Amagor.
Ferry-Morse Seed
Co.
Gill Bros. Seed
Co.
Joseph Harris &
Co.
D. M. Ferry Seed
Co.
1870.
1933.
1918.
1932.
1921.
BREEDING WORK BY PUBLIC AGENCIES
The severe losses caused in the cabbage-growing sections of Wisconsin
by cabbage "yellows" or fusarium wilt led Jones (6),1 of the Wisconsin
Agricultural Experiment Station, to start selection work in 1910
toward the development of yellows-resistant varieties. The work was
continued through the cooperation of J. C. Walker, of the United
States Department of Agriculture, and his associates (3, 7, 8, 29, SO,
1 Italic numbers in parentheses refer to Literature Cited, p. 208.
CABBAGE, ETC.
287
31, 32, 33) to the point where we now have yellows-resistant varieties
of all the major types. A good example of a yellows-resistant cabbage
is illustrated in figure 2. (See the appendix for the list of 10 varieties
and years of introduction.) This one piece of publicly supported
plant improvement work has saved the cabbage-growing industry in
many sections of the country and resulted in an enormous return on
the cost.
Workers at the Iowa Agricultural Experiment Station (14) have also
produced an early yellows-resistant variety of cabbage, Iacope, by
selection on disease-infested soil from the Copenhagen Market variety,
Figure 2. — Comparison of yellows-resistant and yellows-susceptible breeding lines of
cabbage on heavily infected land. Rows a and c, resistant progenies;
row b, susceptible.
and introduced it in 1922. It has since been -very largely replaced by
earlier and more uniform strains from the "Wisconsin work. In 1926
C. E. Myers, of the Pennsylvania station, released a strain of Ballhead
called Penn State Ballhead, which was produced by pedigree selection
for uniformity and solidity of head and for large yields under Pennsyl-
vania conditions. The work of J. C. Miller, at the Louisiana station,
has resulted in the production of a strain called Louisiana Copenhagen,
which is earlier, slightly smaller, and shorter-cored and has harder
heads under Louisiana conditions than commercial strains of Copen-
hagen Market, from which it was produced by inbreeding and selection.
As a result of the inbreeding, hydridization, and selection work of
C. H. Myers and W. I. Fisher at the New York (Cornell) station, nine
new varieties or improved strains of cabbage have been introduced.
288 YEARBOOK, 1937
(See table 4 of the appendix for list and special characters of each.)
Several other State experiment stations and the United States Depart-
ment of Agriculture have cabbage-improvement programs under
way from which no introductions have yet been forthcoming (see
table 6 of the appendix).
Present Trend in Cabbage Improvement
The major emphasis in cabbage breeding is now upon the develop-
ment of strains that are resistant to diseases other than yellows, strains
that are particularly well adapted to a definite locality, or strains with
superior eating or storage quality. There is need for an early-matur-
ing, round-headed, winter-hardy, nonbolting variety of cabbage that
can supplant Jersey Wakefield for wintering-over in the South Atlantic
coastal region. Our best early round-headed varieties are usually
either killed by the cold in this region or produce seedstalks when
planted in the fall. Work on this problem is well under way, and it is
hoped that within a few years a strain or variety will be available that
will combine the hardiness and nonbolting of Jersey or Charleston
Wakefield with the more productive and more desirable head char-
acteristics of Golden Acre or Copenhagen Market. Except for
sauerkraut manufacture, there is a decided preference for heads
of small to medium size, very hard, with mild or sweet flayor and
crisp or succulent texture. The development of strains especially
adapted to cultural conditions in the large production centers in
various sections of the country is another problem on which cabbage
breeders are working.
Usual Breeding Method for Biennial Brassicas
In improving cabbage or other Brassicas by selection, commercial
seedsmen commonly select several plants possessing the desired char-
acteristics and store them over winter either in cold storage or by
burying them in the field under alternate layers of soil and straw or
other coarse litter. As soon as the ground can be prepared in the
spring, the plants are transplanted to their permanent location. In
the case of cabbage, vertical cuts are made on four sides of the head to
enable the seedstalk to push through. The mature seed from each
plant is saved separately, and the plants that result from it are planted
in a separate row the next year. At harvest time only the plants
having the desirable characteristics from the most uniformly desir-
able row (which of course comes from a single head) are selected for
storage and seed production the following year. The breeding block
and the fields for increasing seed should be at least one-fourth mile dis-
tant from any other varieties of Brassicas in order to prevent crossing.
Selling (applying the pollen of the flower to its own stigma and
preventing pollination by other plants) is the most rapid method of
securing uniformity in type, but because of the reduction in vigor
usually caused by inbreeding the Brassicas, the largo proportion of
self-sterility present in these plants, and the special equipment and
large amount of hand labor required, this method has not come into
widespread use by commercial breeders. Various methods of sur-
mounting some of these difficulties are discussed in the section on
Developments in Breeding Technique.
CABBAGE, ETC. 289
American Improvements in Other Brassicas
No plant-improvement work with kohlrabi has been or is being done
by any of the American seed growers or the State or Federal research
institutions. Cauliflower, likewise, has not been worked with success-
fully, because of the difficulties attendant upon seed production in
this country.
Broccoli seed, however, can be grown successfully in California, and
the Ferry-Morse Seed Co. has developed a number of strains that differ
in their ability to make marketable heads at different periods through
the winter and early spring months. The names November, Christ-
mas, February, March Early, March Late, and April indicate the
seasons at which the heads mature most successfully. Green sprout-
ing broccoli, a rather recently revived introduction from Italy, has
been much improved in uniformity of type and productiveness by
several seed growers.2 By proper manipulation it can be easily grown
as an annual to produce seed the first year.
Long Island Improved, a half-dwarf strain of brussels sprouts se-
lected and improved by early Long Island growers and seedsmen, is
the only important variety of this vegetable listed in many American
seed catalogs. Very recently the Gill Bros. Seed Co. of Portland,
Oreg., has introduced a dark-green strain called Oregon Special, and
a medium-green taller strain called Half Moon Bay. The latter
probably developed among the growers in the Half Moon Bay section
of California .
Improvement work on kale by seedsmen has been limited to fixing
the type or selecting more uniform strains. In 1936 the Virginia
Truck Experiment Station released a strain of kale and named it
V. T. E. S. Scotch. It has blue-green, heavily curled leaves and is
more cold-resistant and more uniform than commercial stocks of this
Dwarf Blue Curled Scotch type.
Louisiana Sweet is the name of a uniform, shorter petioled, solid
green-colored strain of collards introduced in 1934 by the Louisiana
Agricultural Experiment Station as the result of several years' in-
breeding and selection work in the Georgia collard variety.
Developments in Breeding Technique
As a result of numerous experiments by workers with cabbage and
related crops, improvements in technique have been made that
greatly facilitate breeding and improvement work. In the work for
early-maturing yellows-resistant varieties of cabbage great difficulty
was experienced in keeping the plants over winter in storage because
of decay and rots that developed during the long storage period. It
was discovered that cutting the roots or pulling them loose on one
side of the plant and then on the other side at a later date would delay
the maturity of the plant until late in the fall. With greenhouse
space available, it was possible to transplant the selected plants into
large pots, which could then be moved into the greenhouse before freez-
2 The only consistent difference between broccoli and cauliflower is that broccoli will produce marketable
curds during the cold winter weather in the Pacific Coast States, whereas cauliflower requires the warmer
weather of the spring season. So the "cauliflower" that easterners get in the winter from the west coast is
grown from broccoli seed. "Green sprouting broccoli" does not form a dense "head" or curd, as is the case
with white-heading broccoli or cauliflower, because the floral branches elongate and are not blanched by
protecting leaves.
290
YEARBOOK, 1937
ing weather. When grown at low temperatures until the seedstalk
started to elongate, these plants would bloom during early spring and
produce seed for sowing in May. This made it possible to treat the
usually biennial or perennial cabbage as an annual and greatly speeded
up the work. It was also more convenient and easier to do crossing
and self-pollination in the greenhouse than in the field. It did not
conflict with other field work in the late spring or early summer.
Figure 3 illustrates the use of a greenhouse for pollination work.
Figure 3. — Artificial control of cross- and self-pollination of cabbage in tbe greenbouse.
The use of the greenhouse in winter makes it possible to obtain a new generation
each year instead of every 2 years.
It was also determined that testing for resistance to yellows could
be done as well in the greenhouse under the proper temperature
conditions (68° to 77.5° F.) in disease-infested soil as in the field.
The plants that proved to be resistant could then be grown to ma-
turity in the greenhouse, and those selected for propagation would
produce seed during the winter and early spring without any period
in storage, where the plants might be lost through disease or decay.
In breeding for shortness of stem or core, compactness of head, and
superior eating quality, it is necessary to remove the head for exami-
nation and testing. When cabbages were grown in Louisiana as a
fall crop, it was found that the axillary sprouts would develop after
the head was cut, and, if the weather was cold enough during Decem-
ber, January, and February, the plants would produce good crops of
seed in time to sow for the next fall crop. If the plants were to be
CABBAGE, ETC 291
moved into a greenhouse the transplanting was delayed until the
lateral sprouts had made a good compact growth.
In some seasons the field-grown plants failed to produce seedstalks
and instead produced small heads from the lateral sprouts. Diffi-
culty was sometimes experienced in getting all of the plants to make
seedstalks when the material was grown in the greenhouse during the
winter. A series of experiments at Cornell University showed that a
rest period of approximately 2 months' duration at about 40° F. was
required for the subsequent formation of seedstalks. This period
could be spent in the fall either in storage or in the greenhouse, and if
the temperature was then raised to 70° and maintained there, ripe
seed could, be produced for sowing in May. Plants that were not
given the cold treatment when grown in greenhouses at a temperature
of 60° to 70° produced no seedstalks, indicating that a period of low
temperature is necessary for the subsequent formation of seedstalks.
Increasing the length of day by the use of 5 hours' electric illumina-
tion at the end of the daylight period did not cause the appearance
of seedstalks in plants grown continuously at the warm temperature
(60° to 70°) or hasten their appearance in the cold-treated plants.
In genetic work the use of pure-breeding or homozygous strains is
advantageous. Various degrees of self-sterility have been encountered
when inbreeding members of the cabbage family to produce such
strains. Numerous lines more or less self-fertile have been isolated,
but the importance of starting with large numbers of individuals
should be emphasized in any program that calls for inbreeding.
Experiments to determine the proper time to pollinate cabbage have
shown that better seed production results when pollinations are made
several days before or several days after the flower first opens. Lines or
families thatproduce practically no seed when pollinated with their own
pollen after the flowers open may produce good crops of seed when pol-
linated from 1 to 5 days before the flower normally opens. Hand-polli-
nation in the bud stage is effected by separating the surrounding sepals
with the points of a pair of tweezers and appl ying the pollen from a mature
anther to the exposed stigma. It is not necessary to remove the sepals,
and in fact they may be helpful in preventing drying out of the pistils.
It has been well established that not only are there various degrees
of self-sterility or self-incompatibility but also there are various
degrees of cross-incompatibility among plants of related or unrelated
origin. Careful hand pollinations are necessary to determine the
exact fertility relations among strains or lines, but the facts when
established are useful in working out a breeding program or in the
production of hybrid seed on a commercial scale, as pointed out by
Pearson (##). By planting in alternate rows strains that are self-
incompatible but cross-fertile, hybrid seed will result through the
action of insects in carrying the pollen from one strain to the other.
Bud pollination of a few flower clusters of each strain results m enough
seed to perpetuate the strains for later crops. Bees have been found
to be very effective agents in the cross transfer of pollen, and by
enclosing the individuals or groups of plants under cheesecloth cages
the bees may be used in working out the problem of obtaining desirable
crosses between different strains or increasing the seed of a number
of desirable crosses for preliminary commercial tests (23).
292 YEARBOOK, 1937
When incompatibilities are encountered, it may be possible to
continue the improvement work, by following a method of alternating
selfings with mass increase. The first step is the production by bud
pollination of as large progenies as possible of the desirable indi-
viduals. Most of the commercially important characters are quan-
titative in inheritance and large numbers of plants are necessary to
produce enough individuals of the desired type. A number of
desirable individuals of the same type are selected from the best
line or lines and each lot or group is grown in an isolated location,
where the plants are open-pollinated. The seed from all the plants
of each lot or group are lumped together and sown. Plants of the
desired type are selected from the best lots of this planting and bud-
pollinated. The seed from each bud-pollinated plant is saved sepa-
rately and selections for massing are made only from the best lines.
In a few years it will be possible to eliminate all but one best line,
which, when uniform for the desired characters, may be increased
for commercial use.
Propagation of new plants from the axillary buds or sprouts of
cabbage has been followed by commercial growers of cabbage when it
was desirable to increase the variety or individual as rapidly as possible.
Only recently, however, has it been demonstrated (5) that vegetative
propagation from the head or curd of heading broccoli was possible.
The most satisfactory material was from pieces of the curd with scale
leaves attached. When placed in a propagating house maintained at
55° F. during the night and with low humidity and plenty of ventila-
tion, these developed roots in 20 days, and in 40 days elongation of the
floral axis had taken place.
By transplanting to the field in late spring the shortened stems of
plants that had produced a crop of seed in the greenhouse, Miller (16)
was able to force the development of new heads from lateral buds
during the summer and by subsequent cold treatment to produce
another crop of seed the following spring. By thus manipulating the
environment in which the plants were grown he was able to maintain
the cabbage plant as a perennial and yet produce a crop of seed
annually.
Pearson (22) at the California Experiment Station worked out a
rapid and ingenious method for determining the solidity of the cabbage
head by determining the apparent specific gravity or density.
CYTOLOGY AND GENETICS OF LEAFY TYPES
OF BRASSICA3
Cytological investigations of a number of workers have shown that
the wild cabbage found along the seacoasts of Europe, various varieties
of heading cabbage, kohlrabi, kale, collards, cauliflower, heading
broccoli, green sprouting broccoli, and brussels sprouts all have nine
pairs of chromosomes (ti = 9). No significant differences have been
reported in size or form among the chromosome sets uf any of these
forms of botanical or horticultural varieties. Hybrids among any of
these forms are usually highly fertile, although sterility may sometimes
occur, as is pointed out in the section on genetic studies and in the
article on root crops (turnips and rutabagas). Botanical varieties of
* This section is written primarily for students or others professionally interested in genetics or breeding
CABBAGE, ETC. 293
Brassica oleracea have been successfully crossed with radish (Raphanus
sativus L.) (see the article on root crops), and rarely with other species
of Brassica having different chromosome numbers, the resulting
hybrids usually being entirely or highly self-sterile.
The wide diversity of form and function in Brassica oleracea would
seem to make it an ideal species for genetic analysis, and except for
several circumstances, our knowledge might be much more extensive
than it is today. Much of the early work cannot be considered
dependable because open-pollinated varieties were used. The presence
of self-sterility has discouraged many workers from attempting to
secure inbred lines with which critical work could be undertaken.
Many of the horticultural or botanical varieties require 2 years' time
to complete the life cycle and relatively large areas of land. Pro-
vision must also be made to prevent cross-pollination by insects.
Transference of pollen from anther to pistil must be done by hand or
by insects enclosed in the isolation chamber, and extensive use of the
backcross is almost prohibitive because of the large amount of hand
labor required to get a sufficiently large number of seeds. In spite
of these difficulties a number of studies have been made on the inheri-
tance of various characters in the cabbage family. The more important
contributions aio briefly reviewed below under sectional headings
indicating the plant character studied.
In view of the wide range of materials used it is not surprising that
the workers report different results with what appear to be the same
characters. It is obvious that critical genetic work on the Brassicas
has only begun. T „
J ° Leaf Colou
Kristofl'erson (12, pt. 1) reports on the inheritance of leaf color in
various Brassica oleracea botanical and horticultural varieties. He
tentatively assumes the interaction of five factors, each with the
following effect: A produces no color alone, but with B produces the
dark red violet midrib; B causes the light-red midrib; C under favor-
able conditions is able to produce a very faint pink color but with A
produces the dark-violet midribs of kale; D causes the general dark-
red color of red cabbage; K is concerned with the distribution of
the dark red violet color.
The factorial composition of the material with which he worked and
its phenotypic appearance with regard to leaf color is given as follows:
Red cabbage, AhcDe, dark red violet midrib and blade.
Kale, Abcde, green midrib and blade.
Cabbage, aBCdE, light-red midrib and green blade.
Brussels sprouts, aBCdE, light-red midrib and green blade.
Broccoli, abCdE, green midrib and blade.
The evidence presented in support of this hypothesis is far from
conclusive, and the author himself in 1927 (12, pt, II) concludes:
"For a linn establishing of the factorial basis of the total dark red
violet color it may be necessary to grow the F3 generation." He
also states in this later paper that the factor D "shows any effect
only when both factors for violet, A and C, are present," which is
evidently at variance with the scheme proposed in the first paper.
Other workers (1, 25, 28) have found a single factor difference
between red (purple) and green foliage. Pease (26) and Molden-
294 YEARBOOK, 1937
hawer (17) conclude that two complementary factors are concerned
in the inheritance of color in a purple kohlrabi X Green Savoy hybrid,
for in the F2 they obtained 9 purples : 7 greens.
C. H. Myers, of Cornell University, has isolated a type designated as
magenta that is more nearly red than the so-called red cabbage, which he
calls purple. Sun red is also a new foliage color name for a genetic type
that shows reddish purple on the stem and midribs and on the edges of
leaves on mature plants exposed to sunlight. Genes controlling purple
and magenta, magenta and sun color, and sun color and green are report-
ed to be allelomorphs respectively. Crosses between magenta and sun
color gave a purple Fi, and 9 purple : 3 sun color : 4 magenta in the F2.
Working with related families, Magruder (1 8) obtained an F2 of 9 purple :
3 magenta : 3 sun color : 1 green from a cross between a magenta and sun
color, indicating the interaction of two independent genes in the produc-
tion of the purple type studied. There was only a single factor difference
between sun color and green and between magenta and green. Kwan
(11) used different families of the Cornell material and in a cross of
purple X sun red the F2 approximated 15 purple : 1 sun red, suggesting
duplicate factors responsible for the purple. The same purple crossed
with green gave an F2 of 9 purple : 3 sun red : 4 green, indicating that
this purple was not the same type as that used by Magruder.
In a review of the inheritance of leaf color it is obvious that a
standard nomenclature should be used or detailed descriptions given
in terms of one of the recognized color dictionaries. Free exchange of
genetic color types among investigators would also facilitate a complete
analysis of color. _ T „
J Other Leaf Characteristics
In a cross between wide blade (cabbage) X narrow blade (kohlrabi),
Pease (25) found the Ft to approach more nearly the broad type, and
in the F2 the narrow type constituted about one-fourth of the total.
Kristofferson (12), however, in a cross between broad (cabbage) and
narrow (kale) found that the I<\ resembled kale and most of the F2
plants had more or less intermediate type leaves, but parental types
were also obtained.
A type of leaf in which outgrowths of a leafy nature called "aspara-
godes" occur along the midrib and larger veins at right angles to the
plane of the blade was found by Pease (26) to be dominant to the
normal leaf type and due to a single factor. Detjen (4) reports a
similar character in his material but believes its expression is due to
multiple factors.
The curliness of kale was found to depend on the action of several
genes. The Fi of a cabbage X kale cross is intermediate in curliness,
and the F2 shows continuous variation between the parental types.
Malinowski (14) assumed three polymeric genes, Allgayer (1) four,
and Pease (26) and Detjen (4) an indeterminate number. Kristoffer-
son (12), however, reports a red cabbage X kale cross in which the
F2 was relatively uniform and in which neither parental type appeared.
Kwan (11) crossed wrinkled (savoyed) and smooth-leaved cabbages
and concluded that the wrinkled condition is due to the comple-
mentary action of two factors. There was no evidence of linkage of
either of the factors for wrinkled leaves with either of the comple-
mentary factors for purple foliage color.
CABBAGE, ETC. 295
Contrasting entire with lyrate leaf shape, Pease (25) found entire
to be due to a single dominant gene.
Petioled type of leaf as contrasted with sessile was found to be due
to a single dominant gene by Pease (25) ; but Allgayer (1 ) postulated
the action of three genes after his study of a cross between red cabbage
and kale. Detjen (4) found the Fi of a cross between winged (sessile)
and petiolate to be fully winged, which is the reverse of the condition
described by Pease (25). He concludes that in his material "clean
E etiolate head leaves are governed by a recessive factor which may
e one of a multiple scries." Environment has a marked effect on
the expression of this character and makes a study of it very difficult.
Counts of the number of leaves below the mature head showed that
in the Fi the number of leaves was generally that of the parent with
the smaller number, btit Pearson (24) concludes that "according to
the evidence, the number of loaves is probably governed by modifying
Height of Plant
Tallness of plants is dominant to dwarfness and is due to a single
geno according to Pease (25), Malinowski (i-4), and Allgayer (1).
KristofTerson (12, ft. II) found continuous variation in plant height
between the parental types in the F2 and concludes that numerous
genes are involved. Detjen (4) also concludes that length of stem
is dependent upon multiple factors for its expression. Kwan (11)
obtained plants taller than his tall parent and shorter than the short
parent in the F2 generation, with the Fi showing marked increase in
height over the tallest parent. He says:
The data suggest that the inheritance of plant height can probably be explained
on the assumption that a series of dominant independent cumulative factors
favorable for growth are concerned, and that each parent strain carried only part
of these favorable factors.
No estimate of the number of factors was made, but the normal distri-
bution of the F2 population indicated that the factors concerned were
of equal value. There was no evidence of linkage between plant
height or plant color or foliage surface.
Head Characteristics
Most investigators have found the Fx from crosses between cabbage
and any nonheading oleracea (except gemmijera) to show a slight
heading tendency, and the F2 to exhibit continuous variation with
recovery of both parental typos, true heads being in the minority.
Malinowski (14) and Allgayer (1) consider that heading depends on
the action of three pairs of genes. Pease (25) attributes it to duplicate
genes, while Detjen (4), working with related headless and heading
types of cabbage, found heading to be "fully dominant among related
plants, or else the heading factor in headless strains is prevented by
one or more factors from clearly manifesting itself."
In crosses between inbred lines Pearson (24) concludes that "head
shape, in general, is controlled by many factors, of no definite dom-
inance." Crosses between long- and flat-headed strains of Copen-
hagen Market showed an intermediate shape. "There is some slight
evidence that certain head factors are complementary to each other,
since one group of crosses produced flatter heads than the parents."
296 YEARBOOK, 1937
Dctjen (4) concludes that "head form is not governed by single factors
but may depend on a combination of several to many factors."
In crosses between inbred lines Pearson (24) found some of the Fj
lines to exceed either parent in weight; in others the Fi equaled the
larger parent; and in crosses between closely related lines no increase
in size resulted in the Fi generation. Detjen (4) records several
crosses in which plant size of the Fi showed size equal to or greater
than the larger parent.
Crossing brussels sprouts (which have axillary heads but no terminal
head) with cabbage (the reverse of brussels sprouts) results in an Yx
that closely resembles the brussels sprouts parent but has a head at
the top. In the F2 there is continuous variation in the tightness of
the axillary buds, with a tendency for most of the plants to have loose
heads or buds. Kristofferson (12) believes the formation of axillary
heads is governed by many factors that are independent of factors for
the formation of the terminal head.
The formation of axillary shoots is due to a single factor and is
recessive to nonformation, according to Allgayer (1).
In crosses among inbred strains differing in the relative length of
the core, Pearson (24) found from his F] results that "no dominance
is shown in the inheritance of penetration of the core into the head."
Hybrids between short- and long-core types have been intermediate
in length. 0 , ,
Season of Maturity
By utilizing inbred lines and Fi hybrids among them, Pearson (18)
concluded that the season of maturity is —
dependent in part upon genetic factors, and that hybridization with resulting
increase in vigor is not necessarily accompanied by an earlier time of maturity;
likewise that environmental differences do not affect all strains in the same
way, and that for a definite test, replications together with check rows are very
necessary.
Detjen (4) says that "heading is found to be governed by a multiple
factor for season, which fact explains the many seasonal strains."
Rasmusson (27) noted an early maturity of the F! from crosses among
varieties of the same season of maturity. In crosses among early-
and late-maturing varieties he notes the F^ as being only a little later
than the earliest parent.
Swollen Stem; Bolting; Corolla Color
The swollen stem or bulb of kohlrabi is incompletely dominant to
unswollen stems (as in cabbage) in the Fif and in the F2 there is con-
tinuous gradation between the parental forms indicating the presence
of several genes for bulbing in the kohlrabi. Pease (26) presents the
clearest data in support of three factors, 5,, B2, and Bs, of which the
first two are major factors and the third a modifying factor. In
homozygous condition Bx and B2 result in bulb, and when either
or both are in heterozygous condition the presence of Bz converts
the stalk into "semibulb" condition. From crosses among related
lines of cabbage differing in their stem diameter, Detjen (4) con-
cludes that stem diameter is hereditary and dependent on many
factors.
CABBAGE, ETC. 297
Certain varieties are known as "bolters" because when sown in the
fall they produce seedstalks instead of heads the following spring.
Sutton (28) crossed a bolting and a nonbolting strain of cabbage and
found the I\ to be nonbolting and the F2 to contain approximately 3
nonbolting : 1 bolting. Detjen (4), working with strains of cabbage
from the Volga variety, found bolting to behave as a monogenic domi-
nant over nonbolting or biennial habit, although he recognizes that
bolting is influenced by other genes for time of maturity and heading-
White corolla color was found by Pearson (19) and Kakizaki (10)
to be due to a single gene and dominant to the yellow corolla color.
Self- and Cross-Incompatibility or Sterility
According to Kakizaki (9), self- and cross-incompatibility in cabbage
is caused by the slow rate of growth of the pollen tubes. In incom-
patible pollinations the slow growth is due to the presence of a sub-
stance that inhibits the growth of pollen tubes through the stylar
tissue and in compatible pollinations the normal growth rate of the
pollen tubes is due either to the absence of the inhibiting substance
or the presence of an accelerating substance able to prevent the in-
hibiting action. The inhibiting substance is produced most abun-
dantly when the pistil is in full vigor, and its production declines with
the decline of the vigor of the pistil. The pseudofertility of bud
pollination of incompatible ma tings is due mainly to insufficient in-
hibiting action, owing to immaturity of the style, and to the lower
time interval for pollen-tube growth, as well as to the shorter distance
to be traversed. Kakizaki's resxilts are explained by the hypothesis
that two contradictory allelomorphic series of genes are concerned.
Su S2, and S? constitute the inhibiting series and Z\ and T2 the ac-
celerating series. The S series is epistatic to the T, but "T in double
dose is more active than S in simple dose," In order to explain
different degrees of fertility it is assumed that the allelomorphs func-
tion in different intensities or that one or more factors of minor value
are concerned. When selfed, some self-incompatible plants breed
true, while others segregate into 1 self-compatible : 3 self-incompatible.
Self-compatible always segregates into 1 self-compatible : 1 self-incom-
patible. Pearson's (21) results "in most respects agree with those
of Kakizaki", and Detjen (4) likewise agrees that —
incompatibility in the common cabbage is governed in the main by a series of
multiple allelomorphs which result in the manifestation of very distinct types.
There are, however, other factors outside of such series that may affect the com-
patibility of plants such as was observed in the complete reversal of the Zinnia
Rosette strain from practically complete self- and cross-incompatibility to prac-
tically full self-compatibility. Environmental factors such as temperature also
may affect seed setting and temporarily mask the genetical factors.
Resistance to Yellows
Walker (82) has clearly demonstrated that resistance to yellows
(Fusarium conglutinans Wr.) is a monogenic dominant to susceptibility
to the disease in most of the yellows-resistant varieties developed by
him and his coworkers. Anderson (2), one of his associates, has shown
that the resistance of Wisconsin Hollander is genetically complex,
as it cannot be permanently fixed and is influenced by environmental
conditions. When grown at 22° to 24° C. all plants of Wisconsin
i:S8904°— 37 20
298 . XEARBOOK, 1937
Hollander are susceptible, while resistant types in which the resistance
is due to the single dominant factor are fully resistant at these
temperatures. T
r Linkage
The results of Pease's work (25, 26) indicate the existence of three
of the possible nine linkage groups. In the first group are found the
genes (or one of a multiple series) for (1) petiolate leaves, (2) one of
the genes for head formation, (3) entire leaves, (4) wide leaves,
(5) possibly one factor for crinkling of the leaf, (6) bulbing of stem,
and (7) red (purple) foliage color. A second group contains (1) a
second gene for head formation, (2) a gene for tall plant habit, and
(3) probably one of the genes for leaf crinkling.
"Asparagodes" malformation of the leaf thus far has not been
linked with either of the above groups.
Malinowski (14) and Pease (25) report complete correlation between
the degree of head formation and curliness in the F2of a cabbage X curly
kale cross. Malinowski inferred that the heading was due to three
pairs of genes, ABC, and that curliness is produced by three other
pairs of genes, XYZ, with complete linkage between A and x, B and y,
and O and z.
LITERATURE CITED
(1) Allgayer, H.
1928. GENETISCHE UNTERSUCHUNGEN MIT GARTENKOHL (BRASSICA OLER-
ACEA) NACH KREUZUNGENVERSUCHEN VON" RICHARD FREUDENBERG.
Ztschr. Induktive Abstain, u. Vercrbungslehre. 47: [191J-260, illus.
(2) Anderson, M. E.
1933. FUSARIUM RESISTANCE IN WISCONSIN HOLLANDER CABBAGE. JoUI'.
Agr. Research 47: 639-661, illus.
(3) Blank, L. M., and Walker, J. C.
1933. INHERITANCE OF FUSARIUM RESISTANCE IN BRUSSELS SPROUTS AND
kohlrabi. Jour. Agr. Research 46: 1015-1022.
(4) Detjen, L. R., and McCue, C. A.
1933. CABBAGE CHARACTERS AND THEIR HEREDITY. Del. Agr. Expt. Sta.
Bull. 180, 147 pp., illus.
(5) Graham, R. J. D., and Stewart, L. B.
1930. vegetative propagation op broccoli from heads. Bot. Soc.
Edinb. Trans. 30: 216-217, illus.
(6) Jones, L. R., and Gilman, J. C.
1915. the control of cabbage yellows through disease resistance.
Wis. Agr. Expt. Sta. Research Bull. 38, 70 pp., illus.
(7) Walker, J. C, and Monteith, J., Jr.
1925. fusarium resistant cabbage: progress with second early
varieties. Jour. Agr. Research 30: 1027-1034, illus.
(8) Walker, J. C, and Tisdale, W. B.
1920. fusarium resistant cabbage. Wis. Agr. Expt. Sta. Research
Bull. 48, 34 pp., illus.
(9) Kakizaki, Y.
1930. studies on the genetics and physiology of self- and cross-
incompatibility IN THE COMMON CABBAGE (BRASSICA OLERACEA
q/vv L. var. capitata l.). Japan. Jour. Bot. 5: [133]-208, illus.
1930. A DOMINANT WHITE-FLOWERED MUTANT OF BRASSICA OLERACEA L.
Japan. Jour. Genetics 6: [55]-60.
(11) Kwan, C. C.
1934. INHERITANCE OF SOME PLANT CHARACTERS IN CABBAGE, BRASSICA
oleraceae, var. capitata. Jour. Agr. Assoc. China 126-127:
81-124, illus. (Thesis, Cornell Univ., privately publ. 1933.
Filed in office of Graduate School, Cornell Univ.)
(12) Kristofferson, K. B.
1924-27. contributions to the genetics of brassica oleracea (i-ii).
Hereditas 5: [297}-364, illus., 1924; 9: [343]-348, illus., 1927.
CABBAGE, ETC. 299
(13) Magruder, It., and Myers, C. H.
1933. THE INHERITANCE OF SOME PLANT COLORS IN CABBAGE. Jour. Agr.
Research 47: 233-248.
(14) Malinowski, E.
1929. genetics op brassica. Bibliographia Genetica 5: 1-26.
(15) Melhus, I. E., Erwin, A. T., and Van Haltern, F.
1926. cabbage yellows, caused by pusarium conglutinans, in iowa.
Iowa Agr. Expt. Sta. Bull. 235, pp. [187]-216, illus.
(16) Miller, J. G.
1929. A STUDY op some factors affecting seed-stalk development in
cabbage. N. Y. (Cornell) Agr. Expt. Sta. Bull. 488, 46 pp.,
illus.
(17) MOLDENHAWER, C.
1928. RECHERCHES BUR CERTAINS CROISEMENTS INTERESSANTS DU GENRE
brassica. Bull. Internatl. Acad. Polon. Sci. et Lettros, CI. Sci.
Math. Nat. (B) 1927: 1049-1071, illus.
(18) Pearson, O. H.
1932. THE INFLUENCE OF INBREEDING UPON THE SEASON OP MATURITY OF
cabbage. Amer. Soc. Hort. Sci. Proc. (1931) 28: 359-366.
1929. A DOMINANT WHITE FLOWER COLOR IX BRASSICA OLERACEA L. Amer.
Nat. 63: 561-505.
(19)
(20)
(21)
(22)
(23)
(24)
1931. METHODS FOR DETERMINING THE SOLIDITY OF CABBAGE HEADS.
Hilgardia 5: 383-393, illus.
1931. FURTHER OBSERVATIONS ON THE TYPE OF STERILITY IN BRASSICA
oleracea, vail OAViTATA. Amer. Soc. Hort. Sci. Proc. (1930)
_ 27: 337-342.
1932. BREEDING PLANTS OF THE CABBAGE GROUP. Calif. Agr. Expt. Sta.
Bull. 532, 22 pp., illus.
1933. INCOMPATIBILITY IN BROCCOLI AND THE PRODUCTION OF SEED UNDER
cages. Amer. Soc. Hort. Sci. Proc. (1932) 29: 468-471.
1934. DOMINANCE OF CERTAIN QUALITY CHARACTERS IN CABBAGE. Amer.
Soc. Hort. Sci. Proc. 31 (Sup.) : 169-176, illus.
(25) Pease, M. S.
1926. genetic studies in brassica oleracea. Jour. Genetics 16:
(2(J) [363]-385, illus.
1927. genetic studies IN BRASSICA OLERACEA. II. THE KOHL RAM.
Jour. Genetics 17: [253]-267, illus.
(27) Rasmusson, J. M.
1932. RESULTS FROM A CROSS CABBAGE X SAVOY CABBAGE. HercdHaS 10:
241-248.
(28) Sutton, E. P. F.
1924. INHERITANCE OF "BOLTING" IN CABBAGE. "TENDENCY TO BOLT"
PROBABLY A RECESSIVE MENDELIAN CHARACTER. Jour. Heredity
15: 257-200, illus.
(29) Walker, J. C.
1930. inheritance of pusarium resistance in cabbage. Jour. Agr.
Research 40: 721-745, illus.
(aO)
. 1933. yellows-resistant lines op jersey wakefteld cabbage. Jour.
Agr. Research 46: 039-648, illus.
(31) and Blank, L. M.
1934. fusarium-resistant Danish baldhead cabbage. Jour. Agr. Re-
search 49: 983-989, illus.
(32) Monteith, J., Jr., and Wellman, F. L.
1927. development op three midseason varieties op cabbage re-
sistant to yellows (fusarium conglutinans woll.). Jour.
Agr. Research 35: 785-809, illus.
(33) and Wellman, F. L.
1928. a survey of the resistance of subspecies op brassica oleracea
to yellows (pusarium conglutinans). Jour. Agr. Research
37: 233-241, illus.
IMPROVING THE
ROOT VEGETABLES
C. F. Poole, Cytologist, Division
of Fruit and Vegetable Crops and
Diseases, Bureau of Plant Industry
J_/ID the ancient civilizations arise in the regions where our common
cultivated food plants originated and were naturally abundant? Or
did man take food plants with him, so that the early centers of civili-
zation only seem to be the centers of origin of the plants? This must
remain an interesting subject of speculation, but few students doubt
that civilization was dependent on the natural locations of the plants.
At any rate, the regions that are now believed to be the natural centers
of origin of the root vegetables (40, 41), } which were used as food long
before recorded history, include practically all of the centers of the
oldest civilizations. The present belief is that in the Old World there
were six of these, with five of which we are here concerned, and in the
New World two major and two minor centers, all of which produced
valuable root vegetables:
(1) Central and western China — radish, turnip, taro (dasheen).
(2) India (except northwestern India) — taro.
(3) Middle Asia (Punjab and Kashmir) — turnip, rutabaga, radish, carrot.
(4) Near Asia — turnip (secondary center), beet, carrot.
(5) The Mediterranean — turnip, rutabaga, beet, parsnip, salsify.
(6) Ethiopia — no root vegetables.
(7) Mexico — sweetpotato.
(8) South America (major) — taro, potato.
(8a) Chile — potato.
(8b) Brazil-Paraguay — cassava.
The theory is that the place where a plant exhibits the greatest
diversity of subspecies and varieties in its natural state must have been
a center of origin of that plant.
The value of the root vegetables is due to the fact that they are
biennials, storing food2 in their roots during the first season to sup-
port the second season's growth. Among the cultivated root vege-
tables, man has been able to select fairly true breeding varieties, which
differ from one another chiefly by the shorter or longer time intervals
they require to reach maturity. In some regions an ordinarily
biennial crop may be changed into an annual, or vice versa, by planting
seed early enough so that the plant will bolt, or produce seed the first
season, instead of enlarging its root for winter dormancy. In all the
biennial crop plants there are numerous varieties reputed to be non-
bolters, meaning that they take longer to mature than varieties not so
designated. Genetically, the hereditary factors governing time to
1 Italic numbers in parentheses refer to Literature Cited, i>. 322.
2 The stored food is most frequently in the form of starch anil starchlikn substances, important elements
in the human diet.
300
ROOT VEGETABLES 301
maturity in most of our root crops must be numerous, and the terms
annual and biennial are not strictly accurate because of the many
gradations.
From the beginnings of agriculture almost to the present there has
been no conscious effort to improve the root vegetables beyond select-
ing seed from particular plants whose roots struck the grower's fancy.
Within the last century, however, there has been more or less con-
tinuous activity in improving plants by crossing diverse types and
selecting new combinations of characters. With the development of
Mendelism into the science of genetics it became apparent that cross-
breeding was essential for rapid plant improvement, and furthermore
that an intelligent hybridization technique required a knowledge of
the breeding behavior of chosen parents. In the case of cross-
pollinated species, like the root crops, the breeding behavior or the
real genetic make-up of the parents can be determined only by
inbreeding to produce lines homozygous or "pure" for their own
characteristics. This must be combined with the keeping of pedigree
records. With all our root vegetables, however, the inbreeding
program is sometimes exceedingly difficult, for two reasons to be
discussed later.
IMPROVEMENT OF ROOT CRUCIFERS
The old method of plant improvement is inadequate for our present
needs. The numerous kinds of insects and fungus diseases attacking
cruciferous root vegetables (turnip, rutabaga, radish) necessitate the
production of new resistant or immune strains by the more recent
methods, including inbreeding, crossing, and the use of wild ancestral
forms in the search for superior qualities. When established com-
mercial varieties are planted in regions where insects are most
numerous or in soils or regions where the fungus diseases are most
THE old method of plant improvement is inadequate for our
present needs. The numerous kinds of insects and fungus diseases
attacking such root vegetables as die turnip, rutabaga, and radish
necessitate the production of new resistant or immune strains by
the more recent methods, including inbreeding, crossing, and the
use of wild ancestral forms in the search for superior qualities.
In all the cruciferous root vegetables the deliberate attempt to breed
for resistance to diseases or to produce special kinds of vegetables
has been neglected thus far. But if practically nothing has been
done in the way of improvement by modern breeding methods, there
has been enough genetic research and working out of adequate
techniques to lay the foundations on which to build a practical
program.
302 YEARBOOK, 1937
damaging, seed can be produced only by plants that are entirely
immune or partially resistant to attack. If no natural immunity or
resistance is found in commercial stocks, it can usually be found by
the introduction of wild ancestral forms of these cultivated vegetables
from their original home sites. In all the cruciferous root vegetables
the deliberate attempt to breed for resistance to diseases or to produce
special kinds of vegetables has been neglected thus far. But if
practically nothing has been done in the way of improvement by
modern breeding methods, there has been some genetic research and
the working out of adequate technique, as will be brought out later.
The ground work has been laid on which to build a practical program.
Breeding of Turnip and Rtjtahaga
The name turnip is commonly applied to vegetables that, in their
present cultivated condition, are botanically classified in three
separate species of the genus Brassica. The point should be stressed,
however, that cultivated forms of plants represent complexes of
characters that make them quite different from their wild prototypes.
This has resulted from many generations of selection for characters,
usually Mendelian recessives, which accumulate in combinations not
found in nature.
In the United States the name turnip is applied to plants of the
species Brassica rapa L.,3 a species wherein all plants examined cytologi-
cally have 10 pairs of chromosomes. In Europe the name turnip
is frequently applied to the group of plants that we call rutabagas
(bagas, or sometimes Swedish turnips), known as B. napus var.
sativa rapifera Hort. by some botanists, and as B. carrwestris var.
napobrassica DC in Bailey's Standard Cyclopedia of Horticulture.
The rutabaga has shown 18 pairs of chromosomes in two cytological
examinations by Karpechenko and Frandsen and 19 pairs in one
examination by Nagai and Sasaoka (29). It is important to know
the number of pairs of chromosomes in a species, or at least in the
particular stocks used for parents, because crosses between species
having unlike numbers of pairs are less easily made and are less
regular in breeding and fertility than crosses between those with the
same number. A discussion of chromosome numbers in the genus
Brassica is given by Pearson (SO).
In general, the chief distinguishing characteristics of the turnip are
that the roots are mostly disklike or decidedly flattened, though rang-
ing from spherical to elongated conical; the leaves are hairy, usually
not fleshy, and greatly varied in outline; and the plants reach maturity
in from 42 to 80 days. The commonly grown varieties show a wide
variation in time to maturity, as the following indicates: D
White Milan 42
SnowBall 43
Purple Top Strap Leaved 46
Purple Top White Globe 55-60
Golden Ball 60-65
Cowhorn 70
Yellow Aberdeen '. 70-80
White Norfolk 76
3 Frandsen and Winge (8), however, in reporting on the cytology and genetics of the progeny from a cross
between the turnip and rutabaga, call the turnip parent B. campeslris var. sativa rapifera, and Vavilov
(41) calls the turnip B. campestris var. rapifera Metzg.
ROOT VEGETABLES 303
The principal turnip varieties reach maturity more quickly than the
principal varieties of rutabagas. Since the turnip and the rutabaga
will readily cross, however, it is probable that these turnips reaching
market size around 65 to 80 days after planting are the results of
natural turnip-rutabaga crosses.
The chief characteristics of the rutabaga, or Swedish turnip, as it is
sometimes known, are a root that is tankard-shaped or elongated,
although sometimes globular; a fleshier and larger leaf than the turnip;
leaves not hairy; and a longer period of time (from 85 to 90 days)
required for reaching the best pulling stage. Among the most com-
monly available yellow-fleshed rutabaga varieties on the American
market are American Purple Top, Early Neckless, and Bangholm.
Two white-fleshed rutabaga varieties are Sweet Russian and White
Disease Resistance in the Turnip
Although no deliberate attempt has been made to breed disease-
resistant varieties of turnips or rutabagas, a new variety of turnip
known as The Bruce, that is highly resistant to the slime mold disease
called clubroot, has recently been introduced in Great Britain, New
Zealand, and Australia. Clubroot attacks many species of the crucifer
family, including cabbage, radish, mustard, cauliflower, sweet alys-
sum, and many others. It is now present in every country where the
common cruciferous vegetables are cultivated. The Bruce is supposed
to be a natural hybrid between the turnip and the rutabaga, and it
first appeared in Scotland about 1820, some 40 years after the time
that clubroot first appeared in Great Britain in 1780. The seed of
The Bruce was carefully guarded in Aberdeenshire, and as it was dis-
seminated throughout the district it was known to local farmers under
different names, until within the last 10 years all agreed on its present
name. The variety is still in a highly heterozygous state; that is, it
appears in a great range of shapes, colors, firmness of flesh, size of seed,
and degrees of resistance to clubroot. Tradition says that the ruta-
baga parent had a purple top and white flesh and that the turnip
parent had a green top and yellow flesh, but these differences are not
enough to account for the persistence of a high degree of variability.
Evidently much of the variability is due to the fact that the two
parents had different chromosome numbers — 10 pairs in the turnip and
18 pairs in the rutabaga — and the present descendants are still segre-
gating for differences in number of chromosomes. From a plant-breed-
ing standpoint it is of interest to note that in tests conducted recently
in Scotland (7) the stocks of The Bruce that- are less resistant to
clubroot proved to be the stocks that have grown on soils less heavily
infected with the slime mold.
Many different forms of clubroot exist, and the studies show that
different varieties of turnips or rutabagas may be resistant to one or
several strains of the slime mold but susceptible to others. Evidently
The Bruce combines the largest number of resistance factors, and some
strains are therefore nearly immune to this disease.
In addition to the fact that some strains have practical immunity
to clubroot, whether grown on limed or unlimed soil, the best strains
of the variety also have a higher percentage of dry matter than other
turnip varieties included in the same test.
304 YEARBOOK, 1937
Breeding of the Radish
The radish, Raphanus satims L., is a native of China and India,
and its cultivation was practiced in ancient Egyptian and Grecian
gardens. Because of its low-food value it has always been more popular
as a home-garden vegetable than as a truck crop. It is a good subject
for genetic study, since it exhibits a wide range of varietal forms in
shape, size, and color of roots, time required from planting to market
maturity, and keeping quality. A number of species crosses involving
the radish have proved of considerable value to the plant breeder as
well as the cytogeneticist. The condition known as self-incompati-
bility, which means that plants cannot normally be fertilized by their
own pollen, is widespread in commercial varieties, but this can be
removed by the selection of self-fertile inbred lines.
The leading radish varieties are most frequently classified according
to the seasons in which they are grown. Spring varieties, such as
French Breakfast, White Tipped, and Scarlet Turnip, are quick-
maturing and require from 24 to 30 days' average time to marketing.
The leading summer varieties — White Icicle, White Strasburg, and
Giant Strasburg — are larger and better keepers and require from about
30 to 42 days to market maturity. The winter varieties, such as Long
Black Spanish, Round Black Spanish, White Chinese Winter, and
Mammoth White, have the largest roots, require 50 to 60 days to
reach market maturity, and keep for several months when well
stored.
Our varieties were all developed by crude selection without the aid
of artificial cross-breeding to produce special types. A considerable
number of genetic analyses have been made with radish, however, and
with these as a beginning it is quite likely that plant breeders will take
advantage of cross-pollination to produce new forms better adapted
for special purposes or localities.
Of great interest from the standpoint of plant breeding is the fact
that the radish has been successfully used in generic crosses with the
cabbage. According to reliable records, the first successful cross
between the radish and the cabbage was made in 1826 by Sageret, a
gifted French plant breeder. This wide cross between two genera has
subsequently been duplicated by several other investigators, with
especially interesting results in the two instances to be reported later.
BREEDING OF THE GARDEN BEET
Although the origin center of the beet, Beta vulgaris L., is well known
to be western Asia and the Mediterranean region, our commercial
varieties have resulted from mass selections, based on the appearance
and quality of roots at the end of the first season, to meet western
European tastes. The beet flower is largely wind-pollinated, and
cross-fertilization can be effected in areas separated a dozen or more
miles. The practice of gathering seed for commercial stocks of beets
from open-pollinated plants is responsible for the maintenance of self-
incompatibility in beet varieties. Recently, however, seedsmen and
geneticists are using specially produced inbred lines to obtain improved
stocks free from rogues and from self-incompatibility (fig. 1).
The pollination technique in the beet, described later, demands
unusual care, because even the protection given by airtight bags will
ROOT VEGETABLES
305
be undone upon removal to effect controlled cross-pollination unless
the breeding plot is removed from possible contamination. Self-
pollination for inbreeding requires isolation, either geographic or
Figure 1. — Effect of inbreeding or line breeding in developing high uniformity and
market quality in beets: A, Stock of Ohio Canner developed by selection and line
breeding from Detroit Dark Red; B, good average commercial stock of Detroit Dark
Red. Note superior uniformity in shape of beets in A as compared with those in B.
physical, and it is necessary to start with strains that are already
self-fertile in some degree.
The leading beet varieties differ considerably in length of growing
season, and the time to market maturity of the most popular varieties
extends from about 57 to 78 days. Beets may be grown so as to be
available on our markets all year round by storing the slower-maturing
306 YEARBOOK, 1937
ones, like Long Smooth Blood, under relatively humid conditions.
The leading varieties are all of the red beet type, and they include
Asgrow Wonder, Crosby Egyptian, Ohio Canner, Detroit Dark Ked,
and Long Smooth Blood.
New beet species from Anatolia, recently imported into Germany
and examined cytologically by Scheibe (1, 88), have chromosome
numbers running in an arithmetical series, with 9, 18, and 27 pairs.
A species with 27 pairs, Beta trigyna Waldst. and Kit., exhibited a
sugar content almost twice as great as that of the best commercial
varieties of sugar beets. From the plant breeder's standpoint this
information indicates that there are still untried species in the wild
origin centers that offer new characters for hybridization and selection.
Moreover, the occurrence of chromosome numbers in arithmetical
series suggests the operation of chromosome doubling in the evolution-
ary history of the genus and gives hope of producing new constant-
breeding hybrids made to order.
BREEDING OF THE CARROT
Although the home of the carrot, Daucus carota L., is western Asia,
all of our present varieties represent western European selections,
many of which were made by Vilmorin, a French plant breeder and
seedsman of the middle nineteenth century. Up to the present, carrot
breeding has been almost entirely a matter of crude mass selection,
based on the appearance of roots at the end of the first season's growth.
This method has produced a surprisingly good range of varietal
types in length and shape of roots, relative thickness of central core,
color of roots, and length of time from planting to market maturity.
Because of the increasing demand for carrots in the dietary, however,
much attention is being given today to the more modern methods of
inbreeding for the purification of commercial stocks and for genetic
analysis, followed by cross-pollination.
Some notion of the uniformity developed in inbred carrot lines may
be gained from the fact that the coefficient of variability in carotene
content (carotene is a yellow coloring matter and the source of
vitamin A) between 28 roots of a commercial strain of Danvers Half
Long was about 33 percent, while the variability between 28 roots of a
fine inbred for four generations was only about 7 percent.4
The leading carrot varieties over the last 20 years have been Chante-
nay, Danvers Half Long, Oxheart, and Nantes, all of which are medium
long, require from 70 to 75 days from planting to marketing condition,
and vary from a large core in Chantenay to a minimum of core in
Nantes. Although the present trend is to develop narrower cores,
there is a limit, because an increasing brittleness of the tops accom-
* Influence on carotene content of inbreeding 4 generations (after Emsweller, JiurreU, and Bortbwick, 6) :
Statistics calculated Commercial Inbred
strain lino
Hoots separately analyzed— number.. 28 8
Mean carotene content mg. 100 g dry matter.. 66 56
Range in carotene content.. _ _ do 32-164 36-80
Standard deviation _ do 23.00 4.06
Coefficient of variability ...percent.. 33. 6±3. 3 7. 0±0. 6
The average carotene content per line among 18 inbred lines descended from 2 original plants varied from
32 to 63 mg per 100 g of dry mattor. One may infer from the above that lines derived from more than 2 origi-
nal plants would have given a greater spread and therefore offer even better inbred lines with higher carotene
content.
ROOT VEGETABLES 307
panies an increasing narrowness of core. The carrot is the last of the
root vegetables to receive the attention of geneticists, owing largely
to misconceptions of the difficulties involved. Selected plants were
allowed to set seed by open pollination because it was believed that
carrots were self-incompatible, and this practice, of course, has largely
nullified the effects of the root selection.
For many years carrot growers and seedsmen did not understand
that the failure of isolated umbels to set seed was due not to self-
incompatibility but to the fact that the stamens of a carrot flower ripen
and shed their pollen some hours or days before the pistil is receptive
to pollen. Consequently, self-pollination is effective only if the stig-
mas of the older flowers can be served by pollen from the anthers of
younger ones. This service is performed by blowflies introduced into
cages in which the entire plant or a major branch is encased ; and by
using this technique which is described in more detail later, Borthwick
and Emsweller (2) demonstrated that all carrot varieties tested were
entirely self-fertile.
Miller (28), in Louisiana, in working with the problem of poor color
in carrots grown on certain soils, found that merely selecting the best
colored roots on soil that was adversely affecting color produced
progenies (whether self-pollinated or open pollinated) having higher
percentages of well-colored roots on unfavorable soils than check com-
mercial strains.
Recent studies indicate that hybrid vigor in the carrot acts as it
does in corn. When two inbred lines producing roots averaging 12.8
and 24.9 g, respectively, were crossed, the first-generation progeny pro-
duced roots that weighed 80.5 g on the average.
Genetic analysis in the carrot has included studies of the inheritance
of such characteristics as branched roots, cracked roots, root shape,
and root color.
IMPROVEMENT OF OTHER ROOT VEGETABLES
Among the root vegetables taro, parsnip, and salsify are relatively
unimportant in the United States, and the number of contrasting
characters available for study is so small that no attention has thus far
been paid them by breeders or geneticists.
Varieties of Taro
The taro, or dasheen, Colocasia esculenta (L.) Schott, seems to have
three centers of origin, China, India, and South America, and up to
very recent times its cultivation was practically confined to the Hawai-
ian and other Pacific Islands, where its fleshy root is the staple food of
the natives, and also to the Mediterranean region. Recently, however,
several introduced varieties of the taro2 Trinidad, Ventura, and Sacra-
mento, were thought sufficiently promising to serve as potato substi-
tutes in the Southeastern States (43, 44)- As early as the seventeenth,
century a few varieties were successfully grown in South Carolina as a
cheap food source for the plantation hands, but the industry failed to
meet competition with importations from the West Indies. The
starch of the root is regarded in Hawaii as superior to that of any other
root vegetable in the ease with which it is digested and assimilated.
Young (48) gives many ways in which the taro root may be prepared
308 YEARBOOK, 1937
as a food, including practically all the ways used with the potato and
the sweetpotato.
No breeding or genetic work has been done with taros, and only in
Hawaii is there any record of seed production. Moreover, many vari-
eties of taro fail to produce an inflorescence, even in Hawaii. The
United States Department of Agriculture has recently begun a project
on taro breeding with the object of introducing a large number of
species and varieties from Hawaii and elsewhere with a view to investi-
gating their genetics and cytology, and also to provide new varieties
with appeal to the growers and consumers of the Southeastern States.
The Parsnip
The parsnip, Pastinaca saliva, L., is a relatively unimportant root
vegetable cultivated in the United States as a market garden crop.
Records show that its center of origin was the Mediterranean region
and that it was introduced into Virginia in 1609 and Massachusetts
in 1629, but thus far there has been no interest in the improvement of
varieties or in the analysis of character inheritance. Only one variety
of importance j Hollow Crown, is grown in this country, and the lack
of varieties with character contrasts is one reason for the failure of
geneticists to attempt any character analysis.
The parsnip is an umbelliferous plant in the same family as the
carrot, and like the carrot it exhibits the phenomenon of protandry,
the pollen being shed long before the stigmas are receptive. The
pollination technique of producing pure strains for variety improve-
ment or genetic analysis is therefore identical with that for the carrot.
Salsify
Salsify (Tragopogon porrifolius L.) or vegetable-oyster — so called
because of a mildly oysterlike flavor — is grown in the United States
on a very small scale and is represented mainly by a single variety,
Mammoth Sandwich Island. Salsify originated in the Mediterra-
nean area, and its introduction into the United States first occurred
about 1806. Practically all the salsify seed produced in this country
comes from a narrow strip along the coast of central California. Its
limited use, as well as the meager representation of character differ-
ences, accounts for the failure of plant breeders or geneticists to take
any interest thus far in its improvement.
Salsify is one of the Compositae, belonging to the same family as
the sunflower. Its fleshy taproot, which resembles a small parsnip,
is handled for curing and storing very much like the dahlia root.
SOME INTERESTING ASPECTS OF
ROOT-CROP BREEDING
In spite of the limited amount of practical breeding work with the
root vegetables, there are certain aspects of the breeding technique
and of the theoretical knowledge attained that are exceptionally
interesting from the standpoint of plant breeding in general. An
effort will be made here to discuss these aspects as simply as possible
for the nontechnical reader. (A technical discussion of root-crop
genetics follows later in this article.)
ROOT VEGETABLES 309
Inbreeding in the root crops is often difficult for two reasons. (1)
It brings out recessive factors for small size and lack of vigor; in other
words, it is just as likely to make undesirable factors "pure" as
desirable ones. Inbred lines frequently are so enfeebled that they
cannot live. In carrots, for example, this is so general as to make it
necessary to proceed with caution in inbreeding and to inbreed several
generations, then outcross to secure enough vigor to go on, then
continue inbreeding until the line is as uniform and homozygous or
"pure" as desired. With beets, on the other hand, many vigorous
upstanding inbred lines have been selected without recourse to out-
crossing. (2) Inbreeding may also uncover recessive hereditary
factors for self -incompatibility.
How do these factors for self-incompatibility act? In the cruciferous
vegetables — including turnip, rutabaga, radish — and probably beets,
the rate of pollen-tube growth of all pollen grains containing such a
factor is retarded if that factor is also present in the tissues of the
style (the stalk of the pistil) through which the pollen tube has to
grow before it can reach the ovary ; in other words, u the factor is pres-
ent in both male and female cells (fig. 2). When the rate of pollen-
tube growth is retarded the male cell cannot reach the female cell in
time to effect fertilization. Self-pollination is thus impossible in plants
that lack the normal alternative (allelomorph) of these self-incompati-
ble genes. The difficulty can be overcome, however, by bud pollina-
tion; that is, applying pollen to the stigmas of unopened buds. This
permits many extra hours of pollen-tube growth before the flower
would normally shod its own pollen.
Commercial varieties that contain genes for self-incompatibility
cannot be pure or homozygous for this characteristic or they could
not reproduce by crossing with other plants of the same variety.
They must in some way be cross-compatible with other plants of the
variety; that is, in a highly heterozygous condition so far as the genes
for seif-compatibility are concerned. The best way to remedy this
situation is to remove the factors for self-incompatibility that prevent
reproduction, by making appropriate crosses to stocks containing the
"normal" alternative genes or allelomorphs; or, more simply, all lines
that are not self-fertile may be eliminated. The situation is Ulustrated
in figure 2.
The last method has been shown to be entirely feasible oven in
such characteristically self-incompatible species as cabbage and beets.
In these species numerous varieties are available that are completely
self-fertile.
All our common root vegetables are biennials, and this somewhat
reduces the speed with which breeding operations may be conducted.
In each case there are also special impediments to breeding operations,
such as self-incompatibility in the cruciferous species, self-incom-
patibility and wind-pollination in beets, difference in the time of
maturity of the male and female organs in carrots, and failure of taro
to produce flowers when grown in most regions. These handicaps,
however, merely tax the ingenuity of the vegetable breeder and make
it necessary for him to develop a special pollination technique for
almost every species. To appreciate some of the problems confronting
the vegetable breeder, it will be well to review the pollination tech-
310
YEARBOOK. 1937
nique now most favored for cross-pollination or self-pollination in the
root vegetables.
The cruciferous root vegetables — turnips, rutabagas, and radishes- —
have relatively large flowers, which are insect-pollinated. This makes
it necessary, in order to effect controlled pollination, to isolate all
flowers from insect contamination by encasing them in cloth or paper
bags or in cages made of netting. Crawling insects may be excluded
by gluing a cotton lining on the inside of the neck of the bag.
To cross-pollinate, the six anthers from the flower of the female
parent must be removed a day before the pollen is shed, thus prevent-
ing any chance of self-pollina-
tion. The following morning
the pollen from the intended
male parent, which likewise has
been bagged, is applied, either
by a camel's-hair brush or by
transferring an entire flower
that is shedding its pollen, to
the stigma of the emasculated
flower of the seed parent.
To self-pollinate, it is neces-
sary, as before, to isolate all flow-
ers from insect contamination.
If the plant is self-compatible,
it will automatically pollinate
itself. Ifitisself-incompatible,
however, it will be necessary to
bud-pollinate ; that is, to apply
pollen from a flower opened this
morning to an as yet unopened
bud of the same plant. The pol-
len will thus have extra time in
which to reach the ovules. It is
even possible that the retarding
principle does not become effec-
W J2
Seeds
Ss, Ss2
produced
l? -Si i
SS Ss,
s,s, s,s2
sisz
S, s,
S\Sz
3,S
Incompatible combinations
—I - I L_
Figure 2. — Diagram showing possible combina-
tions in crosses involving self-incompatibility.
S represents the normal self -compatible genes,
dominant to all the members of the multiple
allelomorphic series, si, S2, and S3 represent -. - ..
self-incompatible genes, recessive multiple alle- tive Until alter the pollen of a
lomorphs of S. No plant can have more than given flower IS shed normally,
two (any two) members of this series. The beet is an example of a
wind-pollinated species that is
also insect-pollinated to some extent. Beet pollen is so small and dust-
like that samples of it have been found by airplanes at elevations of 1,000
feet. Consequently when air currents are in motion the removal of
a bag in order to effect pollination, even for an instant, may result in
contamination of the stigmas with undesired foreign pollen. The best
practice is to pollinate in still air; for example, within a greenhouse.
The floral organs are so small that emasculation is impracticable.
When cross-pollination is desired, an excellent procedure is to make a
cross with a male parent that has some easily identified, dominant
characteristic. All progeny that result from self-pollination will then
show the recessive characteristic and can be discarded in favor of the
hybrids, which can be identified by the dominant characteristic; or
if it is not completely dominant, they will be intermediate in character.
ROOT VEGETABLES 311
The technique developed for sugar beets by Brewbaker (5) is to
isolate the female parent flowers in a hand-made bag 5% inches by 17
inches made of 30-pound vegetable parchment. When cross-pollina-
tion is desired, the danger of uncontrolled pollination may be practically
eliminated by not removing the bag at all, and blowing pollen into it
with a pollen gun, as described by Jenkins (13). As already explained,
self-incompatibility in beets and crucifers prevents successful self-
pollination unless a normal alternative gene (allelomorph) is present.
A strain with such a normal gene might be called a low self-fertile one,
and, as indicated in figure 2 (the fourth ovary from the left), a low
self-fertile strain may be converted by inbreeding and selection into a
high self -fertile strain containing only the dominant normal gene; that
is, a strain homozygous for self-fertility.
As a result of inbreeding experiments with sugar beets, Brewbaker
(3) says: "The characters of high and low self -fertility appear to be
heritable, and by selection and continued self-pollination highly self-
fertile lines would be obtained." It should be said that no genetic
analysis of the inheritance of what is called self-sterility in beets has
been made, but it is assumed to be of the same nature as that out-
lined in figure 2, which in general illustrates the interaction of genes
for self-incompatibility in the cases thus far studied, tobacco and
cabbage.
In carrots.no self-incompatibility is encountered, despite previous
beliefs (£). Self-fertility is complete provided one overcomes the
barrier of protandry, which can be easily done by using the fly-pol-
lination technique of Jones and Emsweller as applied to carrots by
Borthwick and Emsweller (2), for either cross-pollination or self-
pollination.
Since carrot flowers are as small and difficult to emasculate as beet
flowers, cross-pollination is effected most readily by bagging single
umbels in muslin or cheesecloth bags, waiting several days after the
first flowers have come into full bloom, then introducing an umbel of
the male parent with cut stem in a jar of water, along with a supply
of freshly hatched clean blowflies, which will effectively transfer the
pollen to the female umbels. In such cases self-pollination is impos-
sible on a single umbel because of the existence of protandry. Self-
pollination is readily performed by caging an entire plant in a muslin
or cheesecloth bag, then periodically introducing clean freshly hatched
flies. By caging the entire plant the flies are enabled to pollinate
the older flowers with their own kind of pollen from the younger
flowers.
The technique of pollination in taros is very simple. The taro
flower is in the form of a spadix or fleshy axis enclosed by a modified
leaf or spathe, as in the jack-in-the-pulpit or the calla. Each spadix
contains staminate florets on its upper end and pistillate florets on
its lower end. All that is required is to remove the spathe and enclose
the spadix in a glassine or other transparent bag to exclude insects,
and self- or cross-pollinate the female florets as desired with a camel' s-
hair brush. This is sometimes impossible on a single spadix because in
some species of taro the stigmas are past receptivity by the time pol-
len is ready. (This is known as protogyny, the opposite of protandry.)
As a precaution against self-pollination when crossing is desired, it is
312 YEARBOOK, 1937
advisable to remove the male end of the spadix. The real difficulty
with taro, however, is that most varieties will not produce an inflo-
rescence even where they are extensively cultivated, as in Hawaii.
Hybridization between species or genera of the root vegetables has
produced at least three artificial hybrids with all of the chromosomes
doubled. Plants with doubled chromosome numbers of this kind are
known as amphidiploids, and they are usually hybrids between re-
motely related parents. It would seem that on account of the remote
relationship, the chromosomes of the
parents are so dissimilar as to
be unable to mate or pair properly.
The cell-division mechanism is con-
sequently so fundamentally disturbed
as to produce a doubling of the num-
ber of chromosomes in the sex cells.
The first-generation hybrid is likely to
be either entirely sterile or almost so,
but the doubling of the chromosome
number provides all unmated chromo-
somes with mates for pairing, so that in
future generations sex cell division can
proceed in the regular manner. The
result may be a true-breeding amphi-
diploid. In figure 3 all visibly unpaired
chromosomes of the Fx or first hybrid
generation can be seen to be doubled in
C^^W^"*5^^ the amphidiploid hybrid. Frequently,
^rji <=k^ ^ ®5#> however, the chromosome doubling
^^y^JssJQ ffl_c2HS23 takes place in the cells of the plant
body instead of in the sex cells.6
It was only in 1925 that the first
_ amphidiploid hybrid obtained under
■£* experimental conditions was recog-
Figure 3.— Somatic (diploid) chro- nized and described (4). Since then an
mosome sets of tu-o parent species of almost bewildering number of such
hawks-beard: A, Lrepis rubra; B, L. -i i • j r_ -i 3 -t, 1 -mt r
foetida; C, their F, fybrid; D, their hybrids have been described. Many of
amphidiploid hybrid. Chromosome them, because OI the Wide separation
doubling in some Fi sex cells, followed of their two parents, are practically
by a union of two of them, has pro- true-breeding and might truly be called
duced a complete diploid set, quanta- D ■ 1 ■
tively as welf as quantitatively, from new genera ornew species and given
both parents, x about 1,800. new names (42) • Id other cases,
however, the parent species were so
closely related to begin with that many of the chromosomes were
able to pair, and the subsequent chromosome doubling therefore
only resulted in a more complex hybrid, but not a true-breed-
ing one or one that could be expected to produce stable derivatives
(81,32).
Many plant genera contain species whose sex cell chromosome
numbers occur either exclusively or mostly in multiples of some
common number. In wheat (Triticum), for example, some species
'That is, amphidiploids may be formed in two ways— in the gametophyte or sexual generation, and in
the sporophyte or asexual generation.
ROOT VEGETABLES 313
have 7 chromosomes, others 14, and still others 21, in an arithmetical
series. Other examples of genera in which this occurs, with the sex
cell chromosome numbers, are:
Beta (beet) 9, 18, 27
Campanula 17, 34, 51, 8, 16, 10, 13
Chrysanthemum 9, 18, 27, 36, 45
Papaver (poppy) 7, 14, 21, 28, 11, 22
Rosa 7, 14, 21, 28
The occurrence of arithmetical series among the chromosome num-
bers of many genera prompted Winge in 1917 to offer the hypothesis
that such chromosome numbers arose as a consequence of chromosome
doubling following species crosses. At that time he knew of no
experimental verification of his hypothesis, but now there are scores
of artificially produced amphidiploids, as well as evidence of amphidi-
ploid hybrids in the wild, and correlated analyses of characters and
chromosome numbers for their parent species. Two species known
to be natural hybrids are successfully growing in the wild — one a
pentstemon, in the foothills of California, and the other a grass, in
the harbors and on the beaches of the English Channel. The arti-
ficially produced constant breeding amphidiploids in the Cruciferae,
with the number of pairs of chromosomes, are:
(1) Radish, Jlaphanux salivus, 9 pairs, X cabbage, Brassica oleracea L., 9 pairs,
produced "Raphanobrassica", 18 pairs.
(2) Radish, R. sativus, 9 pairs, X Chinese cabbage, B. chinensis L., 10 pairs,
produced "Brassicoraphantis", 19 pairs.
(3) Turnip, B. campeslris L., 10 pairs, X rutabaga, B. napus, 18 pairs, produced
"Brassica napocampestris" , 28 pairs.
Although none of these constant breeding hybrids has commercial
possibilities at present, Brassica napocampestris, combining features
of the turnip and the rutabaga, may easily have value with further
selection, and the others can be used as parents for further crosses to
provide selection material for commercial stocks.
The fact that the chromosome numbers in Beta., from which our
garden and sugar beets come, occur in an arithmetical series, 9, 18, 27,
suggests that species formation in this genus was influenced to some
extent by chromosome doubling following crosses between species.
GENETICS OF Til]-: ROOT VEGETABLES 6
Turnip and Rutabaga
According to Kajanus, turnip more commonly contains hereditary
factors for self-incompatibility than rutabaga. This is expected if
among the larger number of chromosomes of the rutabaga the chromo-
some containing the locus S versus slt s2> etc. (see fig. 2), had been
duplicated; hence segregations for compatibility versus incompati-
bility will show at least a tetraploid rather than a diploid ratio; for
example, an expectation of 35:1 instead of 3:1. The production of
self-fertile inbred lines in turnips will, therefore, be more difficult than
in rutabagas.
Kajanus (IS, 16, 17, 18, 19) has made the greatest number of genetic
analyses in both these species, the main results of which are shown
o This section is written primarily for students or others professionally interested in breeding or genetics.
i:i8!)04 •'— 37 21 ++
314
YEARBOOK, 1937
in tables 1 and 2. Among other geneticists who have worked with
these vegetables are Hallqvist (11, 12), Malinowski (25, 26), and
Sylven (34)- Kajanus studied the progeny of hybrids between these
two species, and Frandsen and "Winge (8) produced an Ft hybrid
between the turnip and the rutabaga that later doubled its chromosome
number. The ensuing amphidiploid stock of plants had the poten-
tialities of a constant new species, combining features from both
parents, but most of them came from the rutabaga, because it con-
tributed most of the chromosomes.
Table 1. — Genetic analyses of character inheritance in turnip
Symbols
PVM..
PVm..
PvM...
Pom...
pVM..
pVm...
pvM...
pvm....'
Phenotypes
Color of hark
Color of flesh
Bed.
.do..
.do-
do.
Gretm.-
do-
Yellow.
. . ..do-
White.
Yellow
White.
Yellow
White.
Yellow
White.
Yellow-
Color of
flower
Yellow.
Orange.
Yellow.
Orange.
Yellow.
Orange.
Yellow.
Orange.
M v. m, white v. yellow flesh color, also yellow v. orange flower color.
P v. p (anthocyanin) , red v. cream-yellow upper root bark color.
V v. v (chlorophyll) , green v. cream-yellow upper root bark color.
P is epistatic to V, thus producing the phenotypic combinations shown above.
Mendelian ratios obtained (Kajanus):
Bark color — 12 red : 3 green : 1 yellow.
Flesh color — 3 white : 1 yellow.
Flower color — 3 yellow : 1 orange.
Root shape — multiple factor inheritance.
Root surface — 3 cracked : 1 smooth.
The hcterozygotes of these genes exhibit an intermediate intensity of expression;
consequently the classification of any hybrid population may be more complex
than is indicated.
Table 2. — Genetic analyses of character inheritance in rutahag'is
Symfxils
Phenotypes
Color of bark
PiP2M,MzEiEiAB. . .
PtPiMiMiEttiAb
PiPzMim&xeiaB -
Pi PimiMiEiEiab
PiPiMiMteieiAli
PiPiM\m&\eiAb
P1P2M i M?E\ei&B
PlP2ttll?H2?lC206
Deep red.
do.—.
do.—.
.do-
Pale red_.
do— .
Green
do-
Color of flesh
White..
....do..
..._ do..
do..
do-
— .do-
do-
Yellow.
Shape of leaf
Pinnatifid.
do-—_.
Kntire
Pinnatifid.
Entire
.do..
Pinnatifid..
Entire
Color of
flower
Yellow.
Orange.
Pale yellow.
Pale orange.
Yellow.
Orange.
Pale yellow.
Pale orange.
A v. a, orange v. pale orange flowers.
B o. b, yellow v. pale yellow flowers.
Pi v. pi, pale violet red v. green.
P2 v. p2, deep violet red v. green.
MiM2 v. JWira2, yellow v. white flesh color.
EiE2 v. eie2, pinnatifid v. entire leaf outline.
P2 is epistatic over Pi, giving the phenotypes shown above.
ROOT VEGETABLES 315
Mondelian ratios obtained:
Bark color — 12 deep red : 3 pale red : 1 green (Kajanus and Hallqvist).
Flesh color — 15 white : 1 yellow (Hallqvist).
Leaf shape; — 15 pinnatifid : 1 entire (Hallqvist).
Life cycle — Biennial v. annual, multiple factors (Malinowski).
Flower color — 9 yellow : 3 orange : 3 pale yellow : 1 pale orange (Sylven) .
The duplicate nature of factorial relations here is an additional
reason for the suggestion that the genes concerned are included in
the extra set of eight chromosomes by which the rutabaga is distin-
guished from the turnip. For example, the two 15:1 segregations
for flesh color and leaf shape indicate duplicate dominant genes for
the dominant allelomorphs in each case. Malinowski, who ana-
lyzed the cross biennial X annual, obtained an observed ratio of
349 biennials to 57 annuals, which gives a significant deviation from
any assumed Mendolian ratio.
Turnip X Rutabaga Crosses
From 1912 to 1917 Kajanus reported studies from a number of
crosses between the two species, turnip, Brassica rapa (10 pairs of
chromosomes), and. rutabaga, B. napus (18 pairs of chromosomes),
with results that have been summarized by Matsuura (27). The
work was done before the acceptance by geneticists of cytological aid
in investigating crosses between parents with differing chromosome
numbers. The studies summarized by Matsuura would have been
more valuable had the investigators considered this feature of the
problem. Most of the analyses made, however, deal only with simply
inherited leaf characters that segregate in the F2 generation with 1:2:1
monohybrid ratios, as, 1 pubescent : 2 intermediate : 1 smooth; or 1
bloom. : 2 intermediate : 1 nonbloom.
The Amphidiploid Hybrid "Napocampestris,'>
In 1932 Frandsen and Winge (#) reported the production under
experimental control of a hybrid between the turnip, Brassica campes-
tris var. sativa rapijera (10 pairs of chromosomes) and the rutabaga,
B. napus var. sativa rapijera (18 pairs of chromosomes). It is unfor-
tunate that an unnecessary confusion should be introduced by calling
the turnip B. caw,pestris here and B. rapa at other times, but the
authors' names have been used. As expected, plants of the first filial
generation were, as a rule, quite sterile compared with the parent
plants. One of the Fx plants, however, proved to be almost as fertile
as the parents. A cytological examination of the root tips of several
¥i plants showed the expected chromosome number of 28 (10 plus 18),
where half the chromosomes from, rutabaga were added to half the
number from the turnip parent. Consequently it is believed that all
the Fi plants, with the exception of the one that was highly fertile,
{possessed 28 somatic chromosomes. The highly fertile plant is be-
ieved to have doubled its chromosomes from 28 to 56 immediately
following fertilization, as in Nicotiana digluta{Jj), because in the progeny
of this plant 21 plants that were examined cytologically were highly
uniform both as to outward appearance and as to the chromosome
number of 56.
316
YEARBOOK, 1937
The progeny of all 28-chromosome Fj plants exhibited a more or
less high degree of sterility, because at the time of formation of sex-
cells the 18 chromosomes from the rutabaga parent had only 10
chromosomes from the turnip parent with which to mate, leaving 8
chromosomes to be distributed to the sex cells at random. Conse-
quently, when these plants were self-pollinated, all sorts of fertilizations
with odd chromosome numbers were effected, many of which proved
to be nonviable, hence the high degree of sterility. Sterility of this
kind is called "generational" sterility, to distinguish it from incom-
patibility, already considered. In the progeny of the 56-chromosome
fertile plant, however, the distribution of chromosomes to the new
sex cells was as regular as though the plant had 28 pairs of chro-
mosomes, the members of each pair separating from each other at
germ cell formation with the regularity of true-breeding natural
species.
An idea of the uniformity of this fairly true-breeding new hybrid
may be gained by comparing its F2 progeny with the parents and the
Ft generation.
Rutabaga: Oval root, red-violet bark, yellow flesh.
Turnip: Elongated root, green bark, yellow flesh.
F[ (a) : The seed of two plants gave half-long roots, red- violet bark, and yellow
flesh in the progeny.
Fj (b) : The seed of one plant gave half-long roots, one-half red- violet and one-
half green bark, and yellow flesh.
F2 generation is shown in table 3.
Table 3. — Distribution of root shapes of turnip-rutabaga hybrids
Nature of hybrid
Diploid
Amphidiploid .
c:iotx>
P'.rcerd
17
Oval
Percent
18
Halflong
Percent
S3
84
Long
conical
Percent
12
16
Bark color
Various.
Green.
In outward appearance as well as in chromosome content most of
the progeny, diploid or amphidiploid, resembled the rutabaga parent
which contributed eight more chromosomes than the turnip. This
may be compared to the observation that in The Bruce turnip most
of the characters usually favor the presumed rutabaga parent. From
the foregoing discussion of Kajanus' analysis of inheritance of root
color in turnips and rutabagas it is seen that green bark is hypostatic
to red bark, which indicates that the rutabaga parent of Frandsen's
amphidiploid hybrid must have been heterozygous for the red bark
factor, and therefore of the genotype PpVV.
Genetics of the Radish
An outline of the chief genetic analyses in the radish, Raphanus
sativus, together with the names of the investigators reporting them,
is given in table 4. The list is compiled chiefly from the work of
Frost (9), Uphof {89), and to a lesser extent Malinowski (25) and
Karpechenko (21, 22). The character contrasts include all organs of
the plant, and the segregations reported show that a fairly simple
factorial situation usually exists.
ROOT VEGETABLES
317
Some question arises regarding the interpretation of results from
the cross red-striped v. white (made from crossing the variety Triumph
with either Early White or Icicle). In Ft red-striped was completely
dominant to white, but in F2 instead of 3 red-striped : 1 white, Uphof
obtained 1 red-striped : 1 white. No cause of the supposed disturbed
ratio was learned, "but Uphof suggested the action of a gamete
lethal, although this ratio might actually be a 9:7 interaction, in
which two recessive whites are involved. Frost's crosses in some
cases showed a pronounced hybrid vigor in Fi, a phenomenon most
frequent in open-pollinated species maintained in a highly heter-
ozygous state.
Table 4. — Character inheritance in Raphanus sativus
1*1 characters
Root:
Yellow v. while
Red v. white
Purple v. red _
Red primary cortex v. white...
Red striped v. white
Longs, globe
Corky v. smooth . ..
Long leaf v. short
Early flowering v. late --
Inflorescence:
White v. yellow
Woody capsule v. papery
Investigator
Yellow
Purple
do
Red
Red striped .
Intermediate
Corky
Intermediate
Early _.
White -.
Woody
3 ycllow:l white
1 red:2 purple:l white
3 purple:l red
15 red: 1 white
1 red striped:l white
1 long:2intermediate: 1 globe...
3corky:l smooth
1 long:2intermediate:l short...
3 early :1 late..
3 white:l yellow : Karpechenko.
Complex inheritance. j Frost.
Uphof, Malinowski.
Uphof.
Frost.
Uphof.
Do.
Do.
Do.
Do.
Frost.
Linkage. — Purple v. red and early v. late arc on the same chromosome.
Species Crosses in the Radish
Crosses are easily made between the wild radish, Raphanus ra-
pJianistrum L., yellow flowered, and the cultivated radish, R. sativus,
red, purple, or white flowered. Both species have nine pairs of
chromosomes, and the cross appears to segregate regularly both as to
chromosome distribution and Mendelian factors. Ft interspecific hy-
brids usually have violet flower color, and, according to Trouard-Eiolle
(36, 37), the starchy root of the wild radish is dominant over the
sugary root of the cultivated radish. Frost found indications of a
linkage between the locus for purple-red root pigment and that for
earliness v. lateness of flowering, with a cross-over of 4.78 percent.
Frost also established the presence of self-incompatibility in the radish,
but made no analysis of its genetics.
Karpeclienko' 's "Raphanobrassica"
Karpechenko (21) obtained a first-generation hybrid between the
radish (2n=18) and cabbage (2n = 18) which was highly sterile as a
result of disparity in chromosome content and structure, although
not in chromosome number, between the two parent species. In
consequence of the cell-division disturbances, some of the functioning
sex cells had double the expected number of chromosomes. The
chance conjugation of two such unreduced sex cells resulted in the
production of a plant having the combined diploid number of chro-
mosomes of the two parents, known as an amphidiploid hybrid.
Karpechenko's amphidiploid hybrid was in some respects like the
318
YEARBOOK, 1937
m
amphidiploid hybrid that Frandsen obtained in the turnip-rutabaga
cross already described. There is one important difference, however,
between Karpechenko's radish-cabbage amphidiploid and Frandsen's
turnip-rutabaga amphidiploid. Frandsen's hybrid presumably re-
sulted from a suspended cell division following the union of the turnip
sperm with the rutabaga egg, whereas Karpechenko's hybrid resulted
from the chance meeting of two un-
reduced sex cells in the ovary of a
first-generation hybrid. Thus we
have illustrations of the two ways
in which amphidiploids can be pro-
duced, (1) where the doubling occurs
in the asexual or sporophyte genera-
tion, and (2) where the doubling
occurs in the sexual or gametophyte
generation.
Figure 4 presents a diagram of the
types of seed capsules characteristic
of the parents and hybrids occurring
in the production of Karpechenko's
amphidiploid, which he called
Baphanobrassica. The hybrid plants
were clearly intermediate between
the two parents in the structure of
capsules, as will be seen from figure
4, but also in possessing as many
kinds of chromosomes from one
parent as the other — radish, Ra-
phanus sativus (2w=18); cabbage,
Brassica oleracea var. capitata
(2n=18); Baphanobrassica (2«=36).
No effort has been made to utilize
Baphanobrassica to improve either
the radish or the cabbage, and
Karpechenko (22) states that it will
not cross back to either of its
parents. It will cross readily, how-
ever, with a large number of other
cruciferous species, including
turnips and rutabagas, which in
turn will not cross with either radish
or cabbage. Karpechenko attempted
to produce still other amphidiploids
with an even higher chromosome number by adding the chromosomes
of turnip, rutabaga, etc., to those of Baphanobrassica. The first-
generation hybrids have succeeded, but thus far the chromosome
doubling to stabilize sex cell formation has not occurred.
From the plant-breeding standpoint the chief value of these studies
is the demonstration of the principle that if a cross cannot be made
directly between species A and B because of their wide evolutionary
separation, then the gap may be bridged by first forming a hybrid
between A and C, with which B will later successfully cross.
w
Figure
representa-
tion of the relative capsule shapes and
sizes, as well as chromosome numbers,
in {A) Raphanus sativus, (/J) Brassica
oleracea, (C) their Fi hybrid, and (D)
their amphidiploid hybrid. Redrawn
from Karpechenko, but the relative
chromosome sizes were somewhat en-
larged in the copying.
ROOT VEGETABLES
319
Terasatva's "Brassico-raphanus'''
In 1932 Terasawa (85) reported the appearance of an amphidiploid
hybrid called Brassico-raphanus with 2n=38 chromosomes, which
bred approximately true in the F4 generation from the cross pakchoi
(Brassicachinensis,2n=20) X radish (Raphanus sativus, 2n=18). He
explained the tardy appearance of this amphidiploid in F4 instead of
F2 as resulting from insect pollination of F2 plants, which somehow
induced nonreduction of chromosomes in sex cells. Consequently,
the origin of Brassico-raphanus from unreduced gametes was in the
main similar to that of Baphanobrassica. The phenotypes of the
two parents and their intermediate hybrid are shown in table 5.
Table 5. —
Comparative
morphology
and theii
of Brassica ch
amphidiploid
iiiensis, Raphanus sativus,
Species
Leaf margins
Roots
! '
Flower color ■ Calyx i Fruit structure
Brassica chinensis.
Entire
Lobod
Intermediate.
Slender
Fleshy
Quito fleshy.
Yellow
Raphanus sativus. .
Closed
Intermediate.
Brassico-raphanus.-
White with pur-
ple veins.
Upper half not de-
hiscent, lower 2
locules.
Genetics of the Beet
Our knowledge concerning the genetics of Beta is obtained chiefly
from the investigations of Kajanus (14, 16, 20) and Keller (28). Some
years ago Kajanus, also Lindhard and Iversen (24), investigated the
inheritance of root color in this biennial root crop, and all believed
that the postulation of two pairs of factors was sufficient to account
for color inheritance. Certain discrepancies in Kajanus' segregation,
which he ascribed to faulty pollination technique, were observed also
by Lindhard and Iversen, who interpreted them as caused by about
37-percent linkage between the two postulated loci. More recently,
however, Keller, with greater care against the contamination of wind-
pollination, investigated the genetics of root color. Instead of only
the two pairs of factors assumed by Kajanus et al., giving 4 segregating
phenotypes in F2, he finds that each of the two loci carries a series of
three multiple allelomorphs.
The genes postulated by Keller in the order of their dominance are:
Locus 1. 2?=red hypocotyl, i?t=red top white hypocotyl, r=ye!low hypocotyl.
Locus 2. Y= yellow root, Y'— green top yellow root, y<= white root.
From two different F2 populations the following series of nine
phenotypes was obtained from combinations of these six genes;
Root phenotypes in garden-beet crosses
Phenotypes Symbols
Red hypocotyl, white root Ry
Red hyopcotyl, red root RY
Palo red hypocotyl, pale red root RY±
Striped red beet RlYr
Green top, red root RY'
Red top, white root R*y
Yellow hypocotyl, white root ry
Green top, yellow root rY'
Yellow beet rY
320
YEARBOOK, 1937
Moreover, instead of a loose linkage of 37 percent, he calculated
an average linkage of 7.3 percent ior four crosses made in the
coupling phase and a linkage of 8.8 percent for a single cross
made in the repulsion phase. Different members of the multiple
allelomorph series were used in the two types of crosses, as shown in
table 6.
Table 6. — Linkage values derived from beet crosses in the coupling and repulsion phases
Crosses
Parental combina-
tions
Recombinations
Total
R*Y*
ry
R'y
rY'
Coupling phase crosses. Recombination percent-
age?^:
ry RlY*
97
143
89
133
114
137
162
109
14
7
9
12
5
12
8
11
230
301
2(58
265
ry ry """
IVY* ry
ry ry
ry R>Y*
ry ry
R'Y* ry
ry ry
Total— - --
464
' 522
1,064
i
Ry
rY*
RY*
ry
Repulsion phase cross. Reeombinatton pcrcent-
age=8.8:
Ry^ry
315
307
2.1
37
082
rY* ry
Kajanus also investigated the genetics of leaf color, but found the
ratios less satisfactory than for root color. In the red-fleshed beets
the distribution of anthocyanin is sometimes general throughout the
stems and leaves and sometimes confined to the stems, petioles, and
larger veins, the rest of the leaf being green. Crosses between red-
containing phenotypes and entirely green-leafed ones gave conflicting
results. Sometimes green appeared to be dominant to red and at
other times it was clearly recessive. He interpreted this paradox to
indicate the presence of a dominant inhibitor for red leaves in some
genotypes which is absent in others.
Finally, for root shape, Kajanus postulated four pairs of genes:
L v. I, long root v. short.
O v. o, inhibitor of L v. noninhibitor.
A v. a, sharp v. blunt forms.
B v. b, inhibitor of A v. noninhibitor.
It has already been noted that the root crops carry several genes
for self-incompatibility, and Beta vulgaris is no exception. Although
no attempt has been made to study the inheritance of self-incom-
patibility in Beta, it is easy to keep these genes out of the populations
by selecting self-fertile inbred lines. The Division of Sugar Plant
Investigations of the Bureau of Plant Industry has selected several
completely self-fertile strains of sugar beets, and Roy Magruder, of
the Division of Fruit and Vegetable Crops and Diseases, has several
promising inbred lines of garden beets.
ROOT VEGETABLES 321
Dudok van Heel (5) with sugar beets and Bateson (10) with sugar,
garden, and stock beets, have investigated the inheritance of bolting.
Both investigators thought inbreeding in beets was impossible because
of self-incompatibility, and thus made their selections from open-
pollinated mother plants. Despite the poor pollen control, both were
able in a short time to select lines that were practically or entirely
nonbolters under any conditions. Bateson rapidly eliminated bolters
by forcing under glass. Dudok crossed high-bolting and low-bolting
strains and found evidence in Fi that low bolting or nonbolting was
dominant, but he attempted no further analysis.
In view of the fact that in radishes Frost found high bolting to be
completely dominant to low bolting in the ratio of 3 : 1 in F2, and that
in rutabagas Malinowski found low bolting partially dominant in Fi
and F2 with indication of multiple factors, it is regrettable that more
complete information is not available for beets. It is probable that
many genetic factors are in operation, from the fact that a wide range
exists between beet varieties in length of time to market maturity.
Genetics of the Carrot
The project of producing inbred lines in carrots as the initial
step in genetic analysis was begun at Davis, Calif., for the pur-
pose of general genetic analysis, variety improvement, and in-
crease of carotene content. The attempt to increase carotene content
in the carrot is impprtant, because it is a rich source of vitamin
A, so necessary in the correction and prevention of certain nutritional
disorders. Betacarotene and vitamin A appear to produce iden-
tical physiological effects. The general genetic analysis includes
the following studies: Branched roots, cracked roots, root shape; wild
v. cultivated root type; three different leaf colors; two flower colors;
purple central flower v. normal; red, white, yellow, purple, and orange
root colors.
At the outset it was observed that inbreeding reduced plant vigor,
but the extent of reduction was difficult to learn, because some
carrot varieties are genetically fast growing while some are slow
growing. A barrier to studying the effect of inbreeding on car-
otene content was encountered in the difficulty of securing repre-
sentative carotene samples from individual roots. Carotene is not
uniformly distributed throughout the root, but apparently is first
deposited at the top of the phloem zone, whence it gradually diffuses
to the bottom of the phloem, and then to the top and bottom of the
xylem core. After many trials it was learned that the most reliable
index of carotene content was a colorimetric reading of the total
extracted pigment before separation of carotene and xanthophyll.
The correlation between the color reading and milligrams of carotene
per 100 g of dry matter is very high. Since the pigment is fairly easily
extracted, but the carotene determination is made only with much
labor, the method is a valuable aid to carrot breeding for increase of
carotene (6).
Studies on average root weight of inbred lines, and of hybrids
among them, show that the numerous growth factors are segregated
to the various lines in a manner corresponding to that for inbred
322 YEARBOOK, 1937
maize lines. Furthermore, the crossing of enfeebled inbred carrot
lines gives the same manifestation of hybrid vigor as in F: hybrids
of maize inbred lines. Presumably the hypotheses developed for size
and weight inheritance in maize are applicable also to carrots, and
we may expect important contributions from carrot genetics to the
solution of the exceedingly difficult problem of size inheritance. An
illustration of production of Ft generations with excessive hybrid
vigor is shown in the following cross between two inbred carrot lines
at Davis, Calif, (data unpublished):
Hybrid vigor in a carrot cross
[Average weight, in grams]
Parent lines, A, 34.28; B, 36.42.
Fourth-generation inbred, A, 12.85; B, 24.87.
Fi hybrid, 80.5.
The variety was Danvers Half Long and parent lines A and
B were from strains inbred one generation. A planting of the
variety from noninbred seed grown and pulled at the same time
had a moan weightof 75 g. Since carrots increase in weight as they
grow, it is necessary to pull at the same time all roots that are to
be compared.
Some work is being done in California on analysis of root color in
carrots.7 In the cross White Belgian X Yellow Belgian the Fi gen-
eration showed plants with the following different phenotypes:
a. White xylem, lemon phloem, white skin.
b. Lemon xylem, white phloem, white skin.
e. "Ringing" of lemon and white, white skin.
In a cross between an Indian purple carrot (purple phloem) X
Commercial Danvers Half Long (orange phloem), the Fi showed vary-
ing degrees of purple.
From the foregoing analysis of Yellow Belgian and White Belgian
it is probable that the picture of a simple monohybrid contrast given
by Tschermak (38) is inadequate.
LITERATURE CITED
(1) Berg, K. H. von
1935. UBER POLYPLOIDS IN DER GATTUNG BETA UND BEI DKK KULTT.'R-
pflanzen ubehhaupt. Zuchter 7: 16-19, illus.
(2) Borthwick, H. A., and Emsweller, S. L.
1934. carrot breeding experiments. Amer. Soc. Hort. Sei. Proc.
(1933). 30: 531-533.
(3) Bkewbaker, H. E.
1934. self-fertilization in sugar beets as influenced by type of
isolator and other factors. Jour. Agr. Research 48: 323-337,
illus.
(4) Clausen, R. K., and Goodspeed, T. H.
1925. interspecific hybridization in nicotiana. ii. a tetraploid
glutinosa-tabacum hybrid, an experimental verification of
winge's hypothesis. Genetics 10: [278]-284, illus.
(5) Dudok van Heel, J. P.
1927. inheritance of bolting in sugar beet. Genetica 9: [217]-236.
illus.
'Unpublished data communicated by P. C. Burrell.
ROOT VEGETABLES 323
(6) Emsweller, S. L., Burrell, P. C, and Borthwick, H. A.
1936. STUDIES ON THE INHERITANCE OP CAROTENE IN CARROTS. Amor.
Soc. Hort. Sci. Proc. (1935) 33: 508-511, illus.
(7) Findlay, W. M.
1931. a disease-resisting turnip. Scot. Jour. Agr. 14: 173-183, illus.
(8) Frandsen, H. N., and Winge, 0.
1932. BRASSICA napocampestris, a new constant amphidiploid
species hybrid. Hereditas 16: [212J-218.
(9) Frost, H. B.
1923. heterosis and dominance op size factors in raphanus. Ge-
netics 8: 116-153, illus.
(10) Hall, A. D.
1928. bateson's experiments on bolting in sugar beet and mangolds.
Jour. Genetics 20: 219-231.
(11) Hallqvist, C.
1915. brassicakreuzen. Bot. Notiser 1915: 97-112.
(12)
1916. ein neuer fall von dimerie bei brassica napus. Bot. Notiser
1916: 39-42, illus.
(13) Jenkins, M. T.
1936. corn improvement. U. S. Dept. Agr. Yearbook 1936: 455-522,
illus.
(14) Kajanus, B.
1912. genetische studien an beta. Ztschr. Induktive Abstam. u.
Vererbungslehre 6: [137J-179, illus.
(15)
(16)
(17)
1912. genetische studien an brassica. Ztschr. Induktive Abstam. u.
Vererbungslehre 6: [217]-237, illus.
1912. mendelistische studien an Ruben. Fiihling's Landw. Ztg. 61:
142-149.
1917. UBER DIE VERERBUNGSWEISE GEWISSER MERKMALE DER BETA- UND
brassica-ruben. ii. brassica. Ztschr. Pflanzenzilcht. 1: [419]-
463, illus.
1917. tiBER bastardierung zwischen brassica napus L. UND brassica
rapa l. Ztschr. Pflanzenzilcht. 5: 265-322.
1913. UBER DIE VERERBUNGSWEISE GEWISSER MERKMALE DER BETA- UND
brassica-ruben. I. beta. Ztschr. Pflanzenziicht. 1: [125J-186,
illus.
(18) -
(19)
(20)
1917. uber die parbenvariation der beta-ruben. Ztschr. Pflanzen-
zftcht. 5: [357]-372.
(21) Karpechenko, G. D.
1928. polyploid hybrids op raphanus sativus l. X brassica oleracea
l. . . . Ztschr. Induktive Abstam. u. Vererbungslehre 48:
1-85, illus.
(22)
1930. A contribution to the synthesis op a constant hybrid op three
species. Vsesoiuz. Sezd Genetike, Selek., Semenov. i Plemenn.
Zhivotnov. Trudy (U. S. S. R. Cong. Genetics, Plant and Anim.
Breeding Proc.) 2: 277-294, illus. [In Russian. English sum-
mary, pp. 293-294.]
(23) Keller, W.
1936. inheritance op some major color types in beets. Jour. Agr.
Research 52: 27-38.
324 YEARBOOK, 1937
(24) Lindhabd, E., and Iveesen, K.
1919. VERERBUNG VON ROTEN UND GELBEN FARBENMERKMALEN BEI beta-
ruben. Ztschr. Pflanzenziicht. 7: 1-18.
(25) Malinowskt, E.
1916. o dziedziczeniu niekt6rych cech tt rzodkiewki (on THE INHERI-
TANCE of some characters in the radishes). Spraw. Towarz.
Nauk Warszawsk. (Compt. Rend. Soc. Sci. Varsovie) 9: 757-776,
illus. [In Polish. English summary, pp. 770-776.]
(26)
1924. KTLKA OBSEBWACJI NAD MIESZANCAMI RODZAJU BRASSICA (QTJBLQTJE8
OBSERVATIONS SUR LES HYBRIDES DU GENRE BRASSICA). Pam.
Zakl. Genetycz. Szkoly Glownej Gosp. Wiejsk. (Mem. Inst.
Gen6tiquc Ecole Super. Agr. Varsovie) 2: 145-162, illus. [In
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zenziicht. 11: 179.
(27) Matsutjra, H.
1933. A BIBLIOGRAPHICAL MONOGRAPH ON PLANT GENETICS (GENIC
analysis) 1900-1929. Sapporo. Ed. 2, rev. and enl., 787 pp.
(28) Miller, J. C, Cochran, F. D., and Garrison, O. B.
1935. SOME FACTORS AFFECTING COLOR IN CARROTS. Amer. SoC. Hort.
Sci. Proc. (1934) 32: 583-586.
(29) Nagai, K., and Sasaoka, F.
1930. chromosome number of crop varieties belonging to cruci-
ferae. additional report. Jour. Okitsu Hort. Soc. 25: 76-77,
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(30) Pearson, O. H.
1929. A SUGGESTED CLASSIFICATION OF THE GENUS BRASSICA. Amer.
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(31) Poole, C. F.
1932. THE INTERSPECIFIC HYBRID, CREPIS RUBRA X C. FOETIDA, AND SOME
OF ITS DERIVATIVES. II. TWO SELFED GENERATIONS FROM AN
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(32)
1933. constant species hybrids. Amer. Nat. 67: 188-190.
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1934. ueber die wildzuckerruben anatoliens, beta lomatogona f.
et m., b. intermedia bge. und b. trigyna w. et k. Angew. Bot.
16: 305-349, illus.
(34) Sylven, N.
1927. KREUZUNGSSTUDIEN BEIM RAPS (BRASSICA NAPUS OLEIFERA).
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p. 390.)
(35) Terasawa, Y.
1932. konstante amphidiploide brassico-raphanus bastarde. Proc
Imp. Acad. Tokyo 8: 312-314, illus.
(36) Trouard-Riolle, Y.
1916. hybridation entre une crucifere sauvage et une crucifere
cultivee a racine tuberisee. Compt. Rend. Acad. Sci.
(Paris) 162: 511-513.
(37)
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(38) TSCHEKMAK, E. V.
1916. tJBER DER GEGENWARTIGEN STAND DER GEMUSEZUCHTUNG. Ztschr.
Pflanzenziicht. 4: 65-104.
(39) Uphof, J. C.
1924. on mendelian factors in radishes. Genetics 9: [292]-304, illus.
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1926. STUDIES ON THE ORIGIN OF CULTIVATED PLANTS. Trudy Prikl. Bot.,
Genetike i Selek. (Bull. Appl. Bot., Genetics and Plant Breed-
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ROOT VEGETABLES 325
(41) Vavilov, N. I.
1935. [Botanical-geographic principles of selection.] 60 pp. Moskva and
Leningrad. [In Russian. Translation in U. S. Dept. Agr., Bur.
Plant Indus.]
(42) Wingb, O.
1932. ON THE ORIGIN OF CONSTANT SPECIES-HYBRIDS. Svensk Bot.
Tidskr 26: [107]-122.
(43) Young, E. A.
1924. TAROS AND YAUTIAS: PROMISING NEW FOOD PLANTS FOR THE SOUTH.
U. S. Dept. Agr. Bull. 1247, 24 pp., illus.
(44)
1936. THE DASHEENJ A SOUTHERN ROOT CROP FOR HOME USE AND MARKET.
U. S. Dept. Agr. Farmers' Bull. 1396, 38 pp., illus.
IMPROVEMENT
OF SALAD CROPS
ROSS C. THOMPSON, Associate Horticul-
turist, Division of Fruit and Vegetable Crops
and Diseases, Bureau of Plant Industry
Ti
HE group of vegetables including lettuce, celery, endive, chicory,
cress, parsley, and cornsalad, of which the leaves or stems, or both, are
eaten raw, are classed as the salad crops. The production and con-
sumption of those crops, especially lettuce and celery, has increased
enormously since their importance as sources of vitamins has become
more generally recognized.
The crops of this group aro comparatively exacting in their cultural
requirements ; hence commercial production is limited to areas that, on
account of certain environmental conditions, are especially suitable
for them. Only the two most important salad crops, lettuce and
celery, are grown in large quantity for market.
Most of the cultivated varieties of the salad plants have arisen by
selection of individual plants by market and home gardeners. In
many cases the parentage and origin are unknown. Only within
recent years has an effort been made to improve these crops by
scientific methods from stock of known worth.
The salad plants other than lettuce and celery will not be dealt with
in the present discussion, as very little work of a scientific nature has
been done with the minor crops of this group. The dearth of material
on the genetics of the salad plants is no doubt in a large measure due
to the difficulties involved in making controlled crosses in many of
these species. These plants all produce small flowers that are dif-
ficult to handle in securing controlled crosses for genetic studies.
Three of them, lettuce, chicory, and endive, are composites, the
flowers of which it is difficult, if not impossible, to emasculate, and
this makes controlled crossing for genetic studies especially difficult.
The drawings in figure 1 show the structure of a lettuce flower,
which is typical of the small-flowered composites. Since the anthers
dehisce, or shed pollen, before the stigma appears beyond the sheath,
it is necessary to remove the pollen from the stigmas and styles in
order to obtain hybrid seed from cross-pollination.
The method of removing the pollen by means of a fine stream of
water, first described by Oliver (4),1 is generally employed. By care-
ful washing with water when the individual florets have reached the
stage of development shown in figure 1, D, it is possible to remove the
pollen from the stigmas of most of the florets within the head. By
applying the desired pollen to heads depollinated with water, a high
percentage of hybrid seed may be obtained from the 15 to 20 ovules
within a flower head. A knowledge of the inheritance of a number of
■ Italic numbers in parentheses refer to Literature Cited, p. 339.
326
SALAD CROPS
327
characters that could be identified in the first generation would greatly
simplify germ-plasm studies in this group of plants. Many problems
in disease resistance and environmental adaptation in the salad crops
are awaiting solution by geneticists and plant breeders, and there is
need for extended research in this field. Although limited in extent
as compared with that on some other crop plants, noteworthy work
in practical plant breeding has been done in the salad group.
LETTUCE
Lettuce is the most important salad plant and one of the most
important of the vegetable crops. The present commercial crop has
~2Jndiv/dual
flowerets
=:inyolucre
,coro//a
-invo/ucre
'6rac&
<—sece/>lac/e
■ ccro/h
grains
- -&y/e
- anther,,
s/ieam
ppoppt/S
Figure 1. — A, The lettuce flower head a few hours before opening. B, A longitudinal
section through a flower head just before opening, showing structure and arrange-
ment of the individual florets within the involucre. C, An individual lettuce floret
removed from the head, showing the floral organs. At this stage, a short time before
full opening, the stigma is completely enclosed by the anther sheath. D, An in-
dividual lettuce floret a few minutes later than C. The rapidly elongating style has
forced the stigma through the apex of the anther sheath. The anthers have already
shed pollen, and some of the grains are lodged among the stylar bristles.
an annual value of about $28,000,000. Lettuce is in demand at all
seasons of the year and is probably grown under more varied condi-
tions in greenhouses and in field culture than any other vegetable.
Cultivated lettuce is known to botanists as Lactuca sativa L. This
species has never been found in the wild state but is generally supposed
to have been derived from the wild species L. scariola L., which is now
widely disseminated and is a troublesome weed in many parts of the
United States. Lettuce is native to India or central Asia. The time
of its introduction into Europe is not known. It is one of the oldest
of the vegetable crops. The records of Herodotus, Pliny, Hippo-
crates, and Aristotle indicate that it was grown as a garden plant in
ancient times. It was reported in China as early as the fifth century
A. D. Mention of it was made by Chaucer in England in 1340. It
was introduced into America from Europe soon after the first colonies
were established. Sixteen varieties were listed as being grown in
American gardens in 1806.
328 YEARBOOK, 1937
Lettuce Types and Their Adaptation
Most horticulturists and seedsmen recognize four classes or types of
lettuce, namely, crisp-head, distinguished by very firm heads of crisp
texture; butter-head, distinguished by soft heads, the inner leaves of
which feel oily to the touch; cos, distinguished by elongated heads,
stiff leaves, and upright habit of growth ; and loose-leaf or bunching,
distinguished by loose, nonhead-forming leaves.
The crisp-head and butter-head types, which form round or flattened
heads, are often spoken of collectively as "cabbage lettuces" to dis-
tinguish them from the "cos lettuces", which form elongated heads.
Many good authorities consider that the cabbage and cos lettuces
have been derived from two distinct botanical types. However, study
of hybrid material from crosses between these two types indicates
that they have a common origin.
Since lettuce is comparatively exacting in its environmental require-
ments during certain periods of its development, large-scale commercial
production is limited to areas where cKmatic conditions are favor-
able during the critical growth periods. These are regions in which
the mean temperatures are comparatively low during the heading
period.
The commercial producing area of the United States can be roughly
divided into three regions: (1) The western, including the Pacific
Coast and Rocky Mountain States of California, Arizona, Colorado,
Washington, Oregon, and Idaho; (2) the northeastern, including
Massachusetts, New York, and New Jersey; and (3) the South
Atlantic, which includes North Carolina, South Carolina, and Florida.
On the basis of production the regions rank in the order named. The
Western States produce approximately 85 percent of the entire crop.
The Western States grow largely the crisp-head type of lettuce,
which sells on the eastern markets as "Western Iceberg." This term
is confusing, as it does not refer to the Iceberg variety but applies to
the numerous strains of crisp-head lettuce shipped to the markets
from the West.
ONE of the notable examples of practical plant breeding was the
development of the Imperial strains of lettuce by the United States
Department of Agriculture. Some years ago the lettuce industry
in parts of the West, the Imperial Valley in particular, was
threatened with ruin by the ravages of two diseases, brown blight
and powdery mildew. The Imperial strains have remade the
industry in these sections. They are resistant to both blight and
mildew, and in certain lettuce-growing areas they now constitute
90 percent of the crop. In addition to their resistance to disease,
each strain shows special adaptation to definite regional and
climatic conditions.
SALAD CROPS 329
Formerly the western crop consisted almost entirely of strains of
the variety New York or Wonderful. Much of the acreage formerly
planted to this variety is now devoted to the disease-resistant Imperial
strains.
Until recently the eastern lettuce crop consisted almost entirely of
the butter-head varieties Big Boston and White Boston, also known
as Unrivaled. In New York, New Jersey, and the Carolinas the
butter-head varieties are being rapidly replaced by strains of crisp-
head New York and the Imperials.
There would no doubt have been a more complete change from
butter-head to crisp-head type in the East except for the fact that the
California strains of crisp-head lettuce have not proved to be adapted
to most parts of the East.
This shift from butter-head varieties such as Big Boston to the
harder head type of lettuce has resulted from consumer demand.
The consuming public has come to prefer the crisp-textured lettuce,
and jobbers and dealers find that it stands handling and shipment
better than the more delicate butter-head varieties. It has become
difficult for eastern growers to find a market for the Big Boston type
when the market can be supplied with the crisp New York or Wonder-
ful type.
Cos or romaine lettuce has never been popular in America, although
it has long been prized by European gardeners and is grown in home
gardens in this country to some extent. There is a limited market for
this type of lettuce among the foreign population of the larger cities.
Although cos lettuce is coarse in texture, the best varieties are of high
edible quality, lacking the bitterness so often present in other types,
especially in some of the crisp-head varieties.
The production of loose-leaf or bunching lettuce is largely confined
to the home garden and to greenhouse culture during the winter
months, when there is considerable demand for this type of lettuce
in some localities.
Greenhouse production of lettuce, which at one time constituted
an industry of considerable importance, has declined rapidly as field
production in the South and West has expanded. Fresh field-grown
lettuce can now be obtained at all seasons of the year. A considerable
quantity of lettuce is grown under glass during the winter months in
the sections around the southern shores of the Great Lakes and near
Boston, Mass. The leaf variety Grand Rapids is the most important
variety around Cleveland, Ohio. The butter-head variety Bolmay
is the leading sort in the Boston section.
History of the Important Lettuce Varieties
When Tracy (6>) published his descriptions of American varieties of
lettuce in 1904, more than 100 distinct varieties were recognized.
Since that time numerous new names have been added to the list.
Until the recent introduction of disease-resistant strains, to be dis-
cussed later, the commercial lettuce crop in the United States con-
sisted largely of two or three varieties. Most of the lettuce reaching
the markets from the West consisted of the crisp-head variety New
York or Wonderful. The eastern crop consisted largely of the butter-
head varieties Big Boston and White Boston.
138004°— 37 22
330 YEARBOOK, 1937
Crisp -Head Varieties
New York or Wonderful is a very large, dark-green, solid, late,
crisp-head variety. It is the most widely used of all lettuces and has
been used as a parent in many of the recently developed strains. The
variety was first named and introduced by Peter Henderson & Co.
in 1896. Its parentage is unknown.
New York No. 12 is an early strain of a lighter color than the
standard variety. It has been one of the most widely adapted crisp-
head strains in the East. It was developed by pure-line selection
from New York and introduced by the Pieters- Wheeler Seed Co.
New York Special No. 41 is a strain of the New York variety intro-
duced in 1927 by the Ferry-Morse Seed Co., of San Francisco, Calif.
It was obtained by pure-line selection from the New York variety.
It is especially adapted to conditions in the Imperial Valley.
Imperial F is one of the best of the strains of the New York type
resistant to brown blight and mildew. It was developed by Ivan C.
Jagger, of the United States Department of Agriculture, from a cross
of New York by a cos variety. It was released in 1930. Imperial
F is now an important variety in parts of the West where brown
blight and powdery mildew are prevalent.
Imperial 615 is a crisp-head lettuce resistant to brown blight, de-
veloped by Ivan C. Jagger from a cross between New York and a cos
variety. It was first introduced in 1934 and has met with general
favor.
Imperial No. 250 was introduced in 1929 by the Ferry-Morse Seed
Co. It was obtained by pure-line selection from Jagger 's Imperial
No. 3. It is a uniform, widely adapted, disease-resistant strain of
Imperial.
Hanson is a yellow-green crisp-head variety, a reliable cabbage-
heading sort, apparently introduced by the Henry A. Dreer Co., of
Philadelphia, Pa., about 1875. Its parentage is unknown.
Mignonette is a dark-green, reddish-brown, crisp-head variety of
high quality but too small for a general market lettuce; it is of un-
known origin and was first named and introduced in 1895 by Peter
Henderson & Co.
The Iceberg variety (which should not be confused with the New
York variety, often marketed as Western Iceberg), is a slightly
pigmented, yellow-green, crisp-head variety. It is one of the most
renable of the crisp-head types for summer. Iceberg was introduced
from Europe and named by W. Atlee Burpee & Co., of Philadelphia,
Pa., about 1894.
Malta or Drumhead is one of the largest of all lettuce varieties.
It is a coarse, light-green, crisp-head variety forming a loose head, of
unknown foreign origin, introduced about 1850.
Denver Market is a very light green crisp-head variety first intro-
duced by F. Barteldes & Co., of Lawrence, Kans., in 1890. Its
popularity has been limited to the Middle West.
Buttei'-Head Varieties
Big Boston is the leading butter-head variety. It is grown in
Europe as Trocadero. It has glossy, entire-margined leaves tinged
with reddish brown. Its parentage is unknown, but it was first
SALAD CROPS 331
named and introduced by Peter Henderson & Co. in 1890. Until
recently Big Boston was the leading variety in the East.
The variety White Boston or Unrivaled may bo described as Big
Boston lacking the tinge of red anthocyaniu pigment and having
slightly lighter green leaves. It was first introduced in this country
in 1902. It is believed to be identical with the variety listed by
Vilmorin-Andrieux & Cie., of Paris, France, as Sans Eival.
White Boston Cornell No. 43 is a large dark-green strain of White
Boston developed by the New York College of Agriculture. It
seems to be well adapted for conditions in New York State.
The variety Salamander or Black-Seeded Tennis Ball is one of the
most popular of the butter-head varieties. It is one of the oldest
varieties of lettuce grown in this country. Its parentage is unknown,
but it was introduced from Europe about 1856.
Deacon, one of the older of the American varieties of lettuce of the
butter-head type, is distinguishable by its peculiar light gray-green
color and its very spreading habit of growth. The variety was
named and introduced by the Joseph Harris Co., of Coldwater, N. Y.,
in 1879.
Way ahead, a more recent addition to the list of lettuce varieties, is
a small, early, bright-green, butter-head variety said to thrive \inder
extremely adverse conditions. It was named and introduced by the
W. Atlee Burpee Co., of Philadelphia, Pa., in 1908.
Belmay is the leading greenhouse variety in the Boston area. It is
a downy mildew-resistant butter-head variety carrying a tinge of
reddish brown. It was developed by the Massachusetts Agricultural
Experiment Station from a cross between May King and the old
reliable forcing variety, Hittinger Belmont. It was introduced in
1928. The variety is discussed later in this article.
Loose-Leaf or Bunching Varieties
Grand Rapids is the most popular of the so-called loose-leaf or non-
heading type. It is quite hardy and well adapted for greenhouse
culture, but not so well suited for growing out of doors. Grand
Rapids was originated and named by Eugene Davis, a market
gardener of Grand Rapids, Mich. It resulted from selection from
the variety Black-Seeded Simpson. The variety was first intro-
duced into the seed trade in 1890 by D. M. Ferry & Co., of
Detroit, Mich.
Early Curled Simpson is a curly, yellow-green, nonheading variety,
one of the best of the nonheading sorts for out-of-door culture. It is
supposed to have originated about 1865 with a market gardener
named Simpson, near Brooklyn, N. Y.
Black-Seeded Simpson is a nonheading variety similar to Early
Curled Simpson, but larger and lighter green. Peter Henderson & Co.
are said to have introduced the variety about 1880.
Prize Head is probably the best of the loose-leaf or nonheading
varieties as regards quality, but is not liked by many on account of its
reddish color, which develops especially during cool weather. Its
origin is unknown, but apparently it was named and introduced by
D. M. Ferry & Co., of Detroit, Mich., about 1868.
332
) /. IK HOOK, ]<J37
Cos or Iioinriine Varieties
Paris White Cos is the most popular of the cos or romaine type.
As a salad lettuce for the home garden it has no superior. It is among
the older varieties grown in this country, having heen introduced from
Europe about 75 years ago, and is considered to he a good variety for
warm weather.
Dark Green Cos is similar to Paris White except that the leaves are
a darker green. Its parentage and origin are unknown.
Lettuce Breeding
The different producing regions have had their specific problems for
the plant breeder. The lettuce industry in some parts of the West,
the Imperial Valley of California in particular, was at one time
. > £ A^ii
tt **tm
Figure 2. — Lettuce plants bagged to prevent uncontrolled pollination. Breeding plots
in the Imperial Valley, Calif. I'alm trees in middle distance.
threatened with ruin by the ravages of two diseases, brown blight and
powdery mildew. A notable example of practical plant breeding is
the development of the mildew and brown blight resistant Imperial
strains of lettuce by Ivan C. .Tagger, of the United States Department
of Agriculture, cooperating with the California growers and shippers.
These strains have remade the industry in some sections of the West.
They are of the general type of the popular and widely grown variety
New York or Wonderftd, and in addition to their resistance to disease,
each shows special adaptation to certain regional and climatic condi-
tions in the West. The breeding work was started in 1923 at Chula
Vista, Calif. A lettuce-breeding plot in the Imperial Valley is
illustrated in figure 2.
The strains resistant to both mildew and brown blight were given
a letter in addition to the mime Imperial. Jagger's other strains have
been identified by numbers. The first brown blight-resistant strains
released were obtained by selection from the variety New York.
SALAD CROPS 333
The mildew-resistant strains were obtained by selection from material
resulting from crosses between the New York variety and European
varieties found by severe tests to be resistant to mildew. In some of
the most important lettuce-growing sections of California, these
strains now constitute 90 percent of the crop.
Imperial F has already been described. Imperial 13, introduced
in 1932, was selected from hybrid material from a cross of New York
with the French variety White Chavigne. Imperial 152 and Imperial
615, introduced in 1934, and Imperial 847, released in 1936, were all
derived from a cross between New York and a cos variety.
One of the serious problems of eastern lettuce growers is the lack
of crisp-head varieties of the New York or Wonderful type that will
thrive under eastern soil and climatic conditions. The lack of varie-
ties adapted for the East is explained by the fact that California not
only grows more of the commercial lettuce crop than any other State
but produces almost the entire seed supply for the United States.
This concentration of the production of lettuce seed in California
has resulted in the building up, through a long period of selection,
of seed stocks especially adapted to western conditions but not to
other sections of the country. Western crisp-head varieties almost
always fail when tested in the East.
Breeding investigations for the purpose of developing strains of
head lettuce of the New York type adapted for eastern conditions
was begun by the writer in 1928. The work was begun at the Arling-
ton Experiment Farm, Arlington, Va., and was moved to the United
States Horticultural Station at the National Agricultural Research
Center, Beltsville, Md., in the spring of 1935. The first strain re-
sulting from this project was released under the name of Columbia
No. 1 in the spring of 1936. A similar but earlier strain was intro-
duced in the fall of 1936 as Columbia No. 2. These two varieties were
selected from material obtained from a cross made in 1928 between
the varieties New York and Hanson. Their chief merit is their
adaptability to soil and climatic conditions in some parts of the East.
A third strain introduced in the fall of 1936 as Cosberg is a distinctly
new type of head lettuce resulting from a cross of the varieties Iceberg
and Paris White Cos. Trial tests of Cosberg show it to be capable of
producing solid heads comparatively free of tipburn under conditions
that result in severe tipburn in most varieties that will head at a high
temperature.
As the breeding work at the Arlington Experiment Farm and the
United States Horticultural Station has progressed it has become
increasingly evident that the wide range of soils and climate existing
in the producing centers of the East will require the development of
strains especially adapted to local conditions. For example, it is evi-
dent that strains adapted for the muck soils of northern New York
State are not likely to prove suitable for the soil and climate of the
Carolinas, and that strains adapted for the lettuce section of Florida
are not likely to meet the needs of growers in Massachusetts.
• Within the last 2 years the Division of Fruit and Vegetable Crops
and Diseases, in cooperation with the State experiment stations in
New York, Massachusetts, New Jersey, and North Carolina, has
undertaken the development of lettuce strains of the crisp-head type
334 YEARBOOK, 1937
adapted for the particular conditions prevailing in these different
sections. The plan is to make available to the State experiment sta-
tions the breeding stocks developed at the United States Horticultural
Station. In this way it is believed that the large amount of hybrid
material now on hand can be used more effectively in securing strains
to meet the needs of the several lettuce-growing centers in the East.
Plant breeders are becoming more conscious of the importance of
local adaptation of varieties in their crop-improvement work. The
needs of widely separated production centers cannot be met by one or
two strains of a variety. No one strain is so cosmopolitan that it can
adjust itself to such extremes of soil and climate.
Growers of greenhouse lettuce also have problems that have re-
quired the attention of the breeder. One of these is the loss from tip-
burn. This is a physiological break-down of the tissues at the margins
of the actively growing leaves. The first appearance of the trouble
is characterized by a breaking down of the marginal tissue between the
larger veins. The affected area becomes somewhat transparent, loses
its green color, and finally becomes brown or blackish. The disease
is widespread, occurring wherever lettuce is grown, both under green-
house and field culture, but it is usually most destructive in green-
houses. It is most likely to appear if high temperature prevails when
the plant is in an active stage of growth and especially at the time the
plant nears maturity. Much loss is caused by infection of the tip-
burned tissues by fungus diseases.
The Ohio Agricultural Experiment Station has contributed to the
solution of this problem by the development of a strain of Grand
Rapids lettuce resistant to tipburn. This is a dark-green, rapidly
growing strain, selected from the standard leaf variety, Grand Rapids,
and adapted for greenhouse culture.
One of the aims of the breeding work being carried on at the United
States Horticultural Station by the Division of Fruit and Vegetable
Crops and Diseases is the development of tipburn-resistant strains for
field production. The Cosberg variety already released is a step
toward the solution of this problem.
Mildew is also a serious problem in the production of lettuce under
glass. It has been met by the downy mildew-resistant strain of Grand
Rapids developed by Ivan C. Jagger in California, and by the powdery
mildew-resistant variety Belmay developed by the Massachusetts
Agricultural Experiment Station at Waltham, Mass.
The Jagger strain of Grand Rapids, developed from a cross between
Grand Rapids and a cos variety, is a heavier, stalkier strain than the
standard variety. It was released in 1936 as Grand Rapids U. S. No. 1.
Belmay is a butter-head type of lettuce adapted for greenhouse
forcing. This is a mildew-resistant variety developed by selection
from material obtained from a cross between the May Kong and the
old reliable forcing variety Hittinger Belmont, or Hothouse. The cross
and preliminary selection work was done by V. A. Tiedjens while he
was a member of the staff of the Massachusetts Agricultural Field
Station at Waltham. Its resistance to powdery mildew and its adapta-
tion for forcing has made it the leading variety for greenhouse produc-
tion in the Boston area.
SALAD CROPS 335
CELERY
Celery ranks next to lettuce in importance as a salad crop. It was
one time considered a luxury but is now a common item in the diet of
many people.
The production of celery has increased rapidly during the last 10
years. The commercial crop now has an annual value of about
$15,000,000. California, Florida, Micliigan, New York, New Jersey,
Colorado, and Oregon produce almost the entire celery crop of the
country.
Celery (Apium graveolens L.) is a biennial plant native to the low
marshlands of southern Europe, northern Africa, and southwestern
Asia. A wild form is native in the southwestern United States.
Although the plant was known to ancient peoples, recorded history
indicates that it was not used as an article of food until modern times.
Its development as a garden plant began among the gardeners on the
lowlands of Italy and spread to France and England. By selection
the undesirable wild plant, long considered poisonous, has been trans-
formed into a crisp, sweet, appetizing, and wholesome item of food.
The commercial producing areas are even more limited than in the
case of lettuce. The production of the early yellow type of celery is
centered in the Sacramento district of California, the Sanford district
of Florida, and the Kalamazoo district of Michigan.
Winter or green celery is produced in the market-garden sections
around Great Salt Lake, Utah, Denver, Colo., Boston, Mass.,
and the trucking sections of New York, New Jersey, Michigan, and
Pennsylvania. TT „ ,T
History of Celery varieties
There are two distinct types of celery — (1) yellow or summer celery,
of which the variety Golden Self -Blanching is typical, characterized by
its early maturity and ease of blanching, and (2) green or winter
celery, of which Giant Pascal is typical, maturing later and having
greater weight and better quality than the early yellow type. The
yellow type can be blanched in the field as it stands in the row by
excluding light merely by means of paper or boards. The green or
winter varieties are more difficult to blanch. The plants must be either
banked with soil as they stand in the row so that only the tips of the
leaves are exposed to light or they must be dug and placed in light-
proof pits to destroy the green coloring of the petioles.
Most of the old standard celery varieties — such as Golden Self-
Blanching, Giant Pascal, White Plume, and Winter Queen — are of
unknown parentage and origin.
Yellow Varieties
Golden Self-Blanching is one of the oldest of the yellow celery
varieties. It has long been a standard variety in France and was very
likely introduced to the United States from Europe. Its parentage is
unknown. For many years French-grown seed of this variety was
considered to be superior to American-grown stocks. Good strains of
American-grown seed are now available. There are both tall and dwarf
strains of this popular variety.
Easy-Blanching is a tall yellow celery resembling Golden Self-
Blanching but a little later in maturing and having bright rich green
336 YEARBOOK, 1937
foliage. It is claimed that Easy-Blanching is hardier and more resist-
ant to blight than Golden Self -Blanching.
"White Plume is the earliest and most easily blanched of all celery
varieties. The blanched petioles are snowy white. Most strains of
this variety have the weakness of not keeping well after digging.
Golden Plume is one of the best of the early varieties. It is some-
what resistant to blight and keeps well in storage. The plants are
medium in size, compact, and stocky. It is earlier, staikier, and
more vigorous than Golden Self-Blanching.
Some of the more recently developed yellow varieties include the
yellows-resistant Michigan Golden and Curly Leaf Easy-Blanching,
introduced by the Michigan Agricultural Experiment Station in 1933
and 1936, respectively; Non-Bolting Golden Plume, Golden Pascal,
Crispheart, and Golden Supreme, developed and introduced by the
Ferry-Morse Seed Co. „ T7. . .
J (jreen Varieties
Giant Pascal is one of the oldest of the green varieties. It is con-
sidered the standard of excellence in celery. The plants are tall and
have rich dark-green foliage. The large thick petioles when blanched
in soil are tender and crisp and have a rich nutty flavor. It is prob-
ably of European origin.
Winter C^ueen is a dark-green dwarf celery resembling Golden Self-
Blanching in habit of growth. It matures earlier and is more easily
blanched than Giant Pascal. It is probably an American variety,
although its parentage is not known.
Fordhook is one of the best of the winter celery varieties, having
good keeping qualities. The plants are somewhat dwarf in habit of
growth, and the petioles are thick and heavy. It was named and
introduced by the W. Atlee Burpee Co., of Philadelphia, Pa., in 1915.
A recent addition to the list of green varieties of celery is Utah.
This is a strain of winter celery developed by the Chinese gardeners
around the Great Salt Lake in Utah. The strain has also been called
Chinese celery. It is a green celery of high quality, a week to 10
days later than Giant Pascal. The variety seems to be well adapted
for some of the irrigated sections of the West.
Recent Celery Improvement
Celery growers look to the plant breeder for the solution of some of
their most serious problems. Among these are the celery yellows
disease, premature seedstalk development, pithiness, and obtaining
earlier maturity.
Some of these problems have already been attacked by plant breed-
ers and much has been accomplished in reducing losses.
Celery yellows first became a serious disease in Michigan. It was
first observed there in 1914 and has since been found in Ohio, Pennsyl-
vania, New York, New Jersey, Massachusetts, and Connecticut.
Only the yellow celery varieties are susceptible, the green varieties
being immune. Plants having the disease lose their normal color and
become stunted; the tissues are brittle and have a bitter taste. The
disease is caused by a species of Fusarium which remains in the soil
and gradually becomes more abundant as celery is grown on the same
land year after year.
SALAD CROPS 337
The first attempt to solve the yellows problem by breeding methods
was initiated by G. H. Coons and Ray Nelson, of the Michigan
Agricultural Experiment Station. The work was later carried on
by Ray Nelson and L. C. Cochran. The first strains released were
resistant to yellows but were found to be too green to blanch easily.
In 1933 the Michigan Golden Yellows Resistant strain was introduced.
It was obtained by selection of yellows-resistant plants from a tall
strain of Golden Self-Blanching.
The Michigan station has also introduced a yellows-resistant
selection from the Newark Market variety. It was released in 1936
as Curly Leaf Easy-Blanching.
Some strains of celery shoot to seed prematurely if the plants are
subjected to low temperature during the early growth period. In
seasons when cold weather prevails after the plants have been set in
the field or in cases where the seedlings in the plant-growing beds
are subjected to low temperature, a heavy loss results from premature
seeding. Emsweller ($) demonstrated the possibility of avoiding
this trouble by breeding nonbolting strains.
The new Non-Bolting Golden Plume variety, developed by the
Ferry-Morse Seed Co., and introduced in 1936, is a step toward the
solution of this problem. The new strain was obtained by pure-
line selection from the variety White Plume. The chief merit of the
strain is its resistance to premature seedstalk formation under con-
ditions that induce early seeding in many of the commercial varieties
of early celery.
Pithiness in celery, a condition in which the parenchyma cells
collapse, resulting in hollow, spongy petioles or stalks, has been
shown by Emsweller (2) to be an inherited character. The estab-
lishment of the genetic basis of pithiness paves the way for the
development by scientific breeding of strains free from this undesirable
character.
The superior quality of green celery of the Giant Pascal type has
long been recognized. On the other hand, the early yellow celery
has the distinct advantage of being much more easily blanched than
the green type. A celery combining the high quality and heavier
stalks of the green celery with the early maturity and easy blanching
characters of the yellow type would be a worth-while breeding
accomplishment. The Ferry-Morse Seed Co. claim to have
approached this in their new strain of Golden Pascal. It is a dark-
green selection from Golden Plume.
The New York State College of Agriculture has investigations
on celery breeding and genetics in progress but has as yet released
no new strains.
GENETICS OF SALAD CROP PLANTS 2
Very little is yet known of the inheritance of characters in the salad
crop plants. Some investigations have been made on the inheritance
of certain characters in lettuce and in celery, but the genetics of only
a few of these is known as yet.
2 This section is written primarily for students and others professionally interested in breeding or
genetics.
338 YEARBOOK, 1937
Lettuce
The most comprehensive study of the germ plasm of a salad crop
plant is that made on lettuce by Durst (1). His investigations
included the inheritance of plant height, time required for flower
production, habit of growth, anthocyanin in the leaves and ray
flowers, prickles on stems and leaves, seed color, leaf length, leaf
width, and leaf area. Both cultivated varieties of Lactuca sativa and
the wild form, L. scariola, were used in his studies.
Durst found anthocyanin in the leaves and ray flowers to be in-
herited as a single factor dominant to the absence of the pigment.
Black seed behaved as if inherted via a single factor dominant to
white seed. Prickles on the midrib of the leaves and on tho stems are
also inherited as a single factor dominant to the absence of prickles.
The inheritance of lobed leaves characteristic of some forms of the
wild species Laciuca scariola is apparently controlled by complemen-
tary factors. The F2 progenies from crosses of lobed with entire-
margined leaf types gave approximately nine lobed to seven entire-
margined.
Leaf length, leaf width, leaf area, time required for flower produc-
tion, plant height, and habit of growth behaved as quantitative
characters, and their inheritance is controlled by many factors.
Thompson 3 has determined the inheritance of certain color
characters in lettuce. A report is made on the inheritance of three
distinguishable anthocyanin pigment types in the leaves, of dark-
green and yellow-green chlorophyll color, of seed color, and of a
chlorophyll deficiency that does not follow Mendelian inheritance.
The three anthocyanin pigment types in the leaves of lettuce
studied by Thompson were the full red type characteristic of the
variety Mignonette, the spotted type characteristic of the variety
California Cream Butter, and the tinged type characteristic of the
variety Iceberg.
The inheritance of these three anthocyanin types was found to be
controlled by a multiple allelomorphic series of three genes and two
pairs of complementary genes. The presence or absence of the
pigment is controlled by the complementary genes and the intensity
and pattern by the multiple allelomorphic series.
Dark-green chlorophyll color, characteristic of the variety New
York, was found to behave as a single factor dominant to the gene for
yellow-green characteristic of the variety Hanson.
Studies on seed color confirm the results obtained by Durst that
black seed is due to a single gene dominant to the gene for white seed.
The chlorophyll deficiency in the leaves of lettuce studied by
Thompson was found to be non-Mendelian in inheritance. The defi-
ciency was inherited only through the deficient portions of the mother
plant,and its inheritance was not affected by the type of pollen applied.
Celery
The inheritance of pithiness in celery has been studied by Emsweller
{2) in the variety Utah. Emsweller isolated inbred lines from this
variety that were homozygous for solid petioles free from pithiness.
3 Thompson, K.C. genetic relations of some color factors in lettuce. (In manuscript; intended
for publication as V. S. Dept. Agr. Tech. Bull.)
SALAD CROPS 339
Progenies from heterozygous linos segregated approximately three
pithy to one nonpithy. The results obtained indicate that pithiness
in celery is controlled by a single factor, dominant to the recessive
condition of solid or nonpithy petioles.
It should be noted here that the problem of pithiness in celery was
practically solved by Sandsten and White (5) in 1900. They ob-
served thai certain stocks of plants of the variety Golden Self-Blanch-
ing from different sources varied greatly in the percentage of pithy
plants produced. Strains of both American- and French-grown stocks
were tested. Lots from the French-grown seed showed much less
pithiness on the average than lots from the American-grown seed.
Some of the French stocks were entirely free of pithiness, which White
and Sandsten, who reported the work, attributed to more careful
selection of seed stocks by French growers. Although Sandsten and
White's results strongly indicated an inherited difference in strains
in respect to pithiness, they failed to carry their investigations far
enough to show a definite genetic relationship.
Premature seedstalk development in celery has also been studied by
Emsweller (8). The varieties Golden Plume and Golden Self-Blanch-
ing were used. Emsweller was able to isolate strains homozygous for
the nonbolting habit, which would not bolt under conditions causing a
high percentage of bolting in other strains. He was able to isolate
some lines that were strongly annual in their seeding habit, some
plants of which seed prematurely even under favorable conditions for
vegetative growth . It is evident from his results that premature seed-
stalk development in celery is inh exited. He concluded that nonbolting
is a quantitative recessive character. The influence of environment on
the expression of the bolting character makes genetic analysis of it
difficult.
LITERATURE CITED
(1) Durst, C. E.
1930. inheritance in lettuce. 111. Agr. Expt. Sta. Bull. 356, pp. 239-341,
illus.
(2) Emsweller, S. L.
1933. AN HEREDITARY PITHINESS IN CELERY. AlUBT. Soc. Hort. Soi. PrOC.
(1932) 29: 480-485, illus.
(3)
1935. PREMATURE SEEDING IN INBRED LINES OF CELERY. Amer. SoC.
Hort. Sci. Proc. (1934) 31: 151-159.
(4) Oliver, G. W.
1910. new methods op plant bheeding. U. S. Dcpt. Agr., Bur. Plant
Indus. Bull. 167, 39 pp., illus.
(5) Sandsten, E. P., and White, T. H.
1902. an inquiry as to the cause op pithiness in celery. Md. Agr.
Expt. Sta. Bull. 83, pp. [101]-] 19, illus.
(0) Tracy, W. W.
1904. American varieties of lettuce. U. S. Dept. Agr., Bur. Plant
Indus. Bull. 69, 103 pp., illus.
See footnote 3, p. 338.
IMPROVEMENT
OF VEGETABLE CROPS-
APPENDIX
VICTOR R. BOSWELL, Principal Horticulturist;
Division of Fruit and Vegetable Crops and Diseases,
Bureau of Plant Industry, from survey data sub-
mitted by domestic and foreign investigators
J. HE appendix to these articles on vegetable improvement consists
of four tabulations of information as follows:
1. A list of vegetable varieties developed by State and Federal research agencies
and released by them for commercial use.
2. A list of vegetable strains, varieties, and breeding stocks or groups of
the same that are in the hands of State and Federal research workers and
which have some special merit, or are of practical or theoretical interest as
breeding material. It should be noted that material listed in table 1 is not
repeated in table 2, although practically without exception introducers of vari-
eties all maintain some stock of their introductions. Table 2 should properly
include all material listed in table 1.
3. A list of vegetable breeding and improvement activities in the United States
by States and crops.
4. A brief summary of vegetable breeding and improvement activities in
countries other than the United States.
The data in these tabulations and summaries were obtained through a question-
naire sent to all vegetable crop research agencies in this country and to a large
number in other lands. The writers of the present articles are grateful for the
generous help of their fellow workers, both here and abroad, in making this
compilation possible. Despite the great amount of data submitted and the
generous response to our requests, it is known that these appended tables do not
contain all of the data that could well be included. Some of the workers inter-
rogated were perhaps too modest to list certain cultures as being important or
of interest to others; others were admittedly too pressed by other matters to
prepare a detailed list of their material and activities. But even though the
data are incomplete, the reader will find clues to nearly every kind of vegetable-
breeding material that is available and leads to the numerous investigators who
are engaged with the hundreds of breeding and improvement problems that are
receiving attention today.
The writers hoped that it would be possible to include similar tables of
information relating to private work by commercial seedsmen. The immen-
sity of the task of determining the origin of the hundreds of varieties made
it impossible. A few commercial firms keep rather complete records of the
parentage and dates of their introductions, but most do not. The major role
that has been played by private agencies has been repeatedly referred to in these
articles, and acknowledgment made to individuals and firms wherever pertinent
information could be included. It should thus be clear to all that no discrimi-
nation is intended by the omission of more extensive data on commercial
contributions. Unfortunately, justice cannot be done to such a task within the
space available here.
340.
Table 4. — Improved varieties and strains of vegetable crops, peanuts, and sweet corn developed and released by State and Federal research agencies
BEAN
Station or
V. S. Department
of Agriculture
Alal)ama_
Connecticut (State) .
Idaho
_do_.
.do-
.do..
_do_.
.do_.
.do..
Maine do..
I
Massachusetts i do..
Illinois.
Crop
Bean.
_do_—
.do
Michigan __
New York (Cornell).
.do..
.do..
| do.—
| do
State (Geneva) I do
do
Department do
do..
do..
.do.,
.do-
Variety name
Alabama No. 1 (pole, snap)
Alabama No. 2 (pole, snap)
Connecticut Fordhook
(liina).
Idaho Refugee (snap)
Great Northern IT. I. No.
81 (held).
Great Northern TJ. I. No.
59 (field).
Great Northern U. I. No.
123 (field).
Large-Podded Henderson
Bush (lima) .
Baby Potato Lima
Ilighmoor Old Fashioned
Yellow Eye (field).
Waltham Scarlet (horti-
cultural).
Robust (field)
Perry Marrow (field)
Genesee (field)
Honeoye (field)
Geneva Bed Kidney
(field).
York Red Kidney (field)..
U. S. No. 1 (snap)
TJ. S. No. 2 (lima)
TT. S. No. 3 (pole, snap) ...
V. S. No. 4 (pole, snap)
U. S. No. 5 (snap)-
Date |
intro-l
duced
Parents
1033
1935
1034
1932
1930
1930
1935
1930
1928
1935
1913
1913
1918
1918
1928
1928
1933
1933
1934
1934
1935
Breeding method
Superior characters
1933 Unknown Selection
do
Fordhook.
Stringless Refugee X Cor-
bett Refugee.
Commercial Great North-
ern.
do
do
Henderson Bush.
do
Old Fashioned Yellow Eye.
French Horticultural
Navy Pea _.
AVhite Marrow X Wells Red
Kidney.
Robust X Wells Red Kidney,
.do..
Wells Red Kidney X String-
less Green Refugee.
Henderson Bush Lima
World Wonder.
Phenomenon Pole _.
IT. S. No. 1 X Torbett
Refugee.
do....
Pure-line selection-
Hybridization
Pure-line selection ..
__._do.— ..
.do-
Cross between two Hender-
son Bush selections.
Selected out of Henderson
Bush; probably an acci-
dental cross.
Selection.
.do..
.do-
Hybridization..
do
.do _
.do
_do_.
_do..
Selection.
....do....
....do...
Hybridization-
Heavy yield; bears over the length of
the vine and over long season; resist-
ant to nematode.
Heavy yield; mature beans keep well
in the field; nematode resistant.
High yield.
Vigor; resistant to bean mosaic; 1 week
earlier than Stringless Refugee.
Productivity, uniformity; resistant to
common bean mosaic.
Larger bean than No. 81; 3 days earlier
in maturity.
Do.
Largo Podded; early, productive under
Illinois conditions.
Henderson Bush vine and earliness,
with small thick potato-type beans,
crowded in pods. Outyields Hen-
derson.
Higher yield; more uniform and attrac-
tive pattern.
Bright scarlet broad, long pods; high
yield.
Immune to common bean mosaic.
Anthracnose resistant; yield.
Anthracnose resistant; root rot resist-
ant.
Do.
Blight resistant, free from hard shell.
Do.
Early, mosaic and drought tolerant.
Early, matures evenly, high yield.
Rust resistant, stringless, Kentucky
Wonder type, round podded.
Rust resistant, large podded, high
yield.
Mosaic resistant; early; long pods; good
yield; determinate growth.
is
o
fcq
2
to
fcq
Co
L
§
CO
Table 4. — Improved varieties and strains of vegetable crops, peanuts, and sweet com developed and released by State and Federal research agencies— Con. jg
B E A N — Con luiucd
Station or
U. S. Department
of Agriculture
Crop
Virginia..
.do..
_do_.
.do-
_._ -do.
— .do..
.
-do-
.do..
Wisconsin __l do-
California.
Georgia —
Louisiana-
Maryland
Massachusetts-
Michigan
New York (Cornell) ..
Spinach ..
do__-
Cabbage.
do...
Collard.
Spinach.
Lettuce.
Celery. _
do...
Cabbage.
do_..
do...
do...
do...
Variety name
Date
intro-
duced
32-0-4 (pole, snap) __
17-B (pole, snap)
17-A (pole, snap). _._ .
14-A (pole, snap) — _
11-A (pole, snap). __.
5-A (pole, snap)-. ...
34-B (pole, snap)..
32-B (pole, snap)
Wisconsin Refugee (snap)
1934
1934
1934
1934
1934
1934
1934
Parents
Kentucky Wonder X Brock-
ton Pole.
do _.
do__
Kentucky Wonder X Horti-
cultural Pole.
do—
Powell Prolific X Marble-
head Pole.
do
Kentucky Wonder X Mar-
blehead Pole.
Stringless Green Refugee X
Corbett Refugee.
Breeding method
Hybridization and selection.
_do_.
.do..
_do-
_do-
_do..
_do-
.do-
Hybridization,.
Superior characters
Rust resistant, prolific and superior
quality of pod.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Resistant to bean mosaic.
LEAFY CROPS
California Canner 159
California Canner 195
Cabbage-Collard- . _
Louisiana Copenhagen
Louisiana Sweet
Maryland Savoy.
Bel-May
Michigan Golden
Curly-Leaf Easy Blanch-
ing.
Early Danish
Green Sugar Loaf
Purple Sugar Loaf
Magenta
Early Savoy1
1929
1929
1911
1934
J 934
1935
1928
1933
1926
1925
1930
1930
1933
1934
Prickly Winter
....do
BlueStemCollard X Charles-
ton Wakefield Cabbage.
Copenhagen Market
Georgia Collard.
Virginia Savoy
May King X Belmont-
Golden Self Blanching..
Newark Market
Commercial Danish
Red X Jersey Wakefield..
do.
Danish Round Red.
Commercial Savoy..
Selection.
.do-
Hybridization
Pure-line selection— inbreed-
ing and intercrossing, 5
generations of selected
lines.
Inbreeding—
Mass selection -
Hybridization-
Single-plant selection.
do
Selection
Hybridization,
.do-
Selection and hybridization.
Selection ...
Early, productive.
Do.
Semiheads of good quality
Uniformity; resistant to bolting; com-
pact head; short, stout core; excellent
quality.
Improved uniformity; short petiole;
compact rosette; more loaves. Free
of purple plants. Good quality.
Winter hardiness.
Downy mildew resistant, good head,
fast growth.
Resistant to celery yellows.
Immune to celery yellows; will blanch
in cold storage; high-quality easy-
blanch type.
Early; short core; good quality.
Table quality.
Do.
New color; good quality.
Uniformity.
£
So
to
©
©
Ohio
Pennsylvania.
Department
Virginia (Truck sta.).
Wiseonsin (in coopera-
tion with depart-
ment).
..._do__
-___do_.
..-.do_.
_...do._
Lettuce.
Cabbage
Lettuce.
„..do...
____do.__
....do...
....do...
....do—
do..
....do..
....do.
Kale...
Spinach..
.do..
Cabbage.
_do_.
.do..
.do..
.do_.
.do-
.do_.
-do.
_do-
_do..
Jersey Wakefield ' 1932
Glory ' 1933
All Ilead Early i 1934
Succession l 1934
Grand Rapids (Tiptmrn 1933
Resistant) .
Penn State Ballhead 1920
Imperial F.
Imperial 13-
Imperial 152
Imperial 615. _
Imperial 847
Grand Eapids C. S. No. 1 .
Columbia No. 1_,
Columbia No. 2_,
1930
1932
1934
1934
1936
1936
1930
1936
Cosberg Xo. 1 | 1936
V. T. E. S. Scotch 1936
Virginia Savoy..
Old Dominion.
Wisconsin Hollander..
Wisconsin Brunswick
Wisconsin All Seasons
Marion Market
All Head Select
Globe
Jersey Queen
Wisconsin Ballhead ....
Racine Market
Kesistant Red Hollander.
1920
1930
1910
1917
1920
1928
1925
1925
1931
1935
1935
1924
Commercial Jersey
Commercial Glory
Commercial Succession..
do
Grand Rapids
Unknown
New York X Cos.
New York X White
Chavigne.
New York X Cos X (?).
New York X Cos
do
Grand-Rapids X Cos
.do.,
.do..
.do.
.do.
.do.
Line selection..
Hybridization.
New York X Hanson,
.—do
Paris White Cos X Iceberg. _
Dwarf Blue Curled Scotch . _
Unnamed Manchurian va-
riety X Bloomsdale, Viro-
fiay, and Long Standing.
Virginia Savoy X King of
Denmark.
Danish Ballhead
.do_.
_do-
_do_.
_do_.
.do_.
_do..
_do_.
do
Pure-line selection-
Hybridization (natural) and
selection.
Hybridization-
Mass seleci ion-
Do.
Uniformity; yield.
Uniformity; type.
Uniformity; yield.
-i Tipburn resistant, light color, very
j heavy.
. I Uniformity of type, good keeping qual-
I ities and high yield.
_ Immune to brown blight; shows
I special adaptations to certain region-
I al and climatic conditions in the
i West.
-I Do.
J Do.
. Do.
Do.
Some resistance to powdery mildew;
heavier, stockier plants than Grand
Rapids.
Superior heading qualities under east-
ern conditions. Slow to shoot to seed.
Earlier than Columbia No. 1; adapted
for spring crop in eastern United
Stales.
Tipburn and heat resistant; high edible
quality, free from bitterness.
More resistant to cold; more curled;
retains dark green color after periods
of low temperatures.
Resistant to mosaic and low tempera-
ture. Rapid growing in fall.
Fottlers Brunswick. _
All Seasons
Copenhagen Market-
All Head Early
Glory of Enkhuizen..
Jersey Wakefield
Danish Ballhead
Copenhagen Market.
Red Hollander
.do..
do..
Pure-line selection.
do
do
do
do....
....do....
.Mass selection
Similar to Virginia Savoy but slower
in bolting to seed in spring.
Resistant to yellows.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
la
ta
ta
to
1 Specially selected strains derived from existing varieties named.
OJ
Table 4. — Improved varieties and strains of vegetable crops, peanuts, and stueet corn developed and released by State and Federal research agencies — Con.
PEA
Station or
TJ. S. Department
of Agriculture
Crop
Variety name
Date
intro-
duced
Parents
Breeding method
Superior characters
Pea
do
1932
1921
1922
1922
1922
1923
1924
1925
1925
1931
1933
1936
Alaska
Horsford X French June
Cross between two Alaska
strains.
do —
Nott's Excelsior X Horsford
Mass selection.
Wisconsin
do.
do
do
do
do
duetion.
No. 19 Alaska
Do.
do
Horal
___do_„
do-
do. _.
Ashford
Pure-line selection .._ ,.
sistant.
Horsford X French June
do
do
do .
do
do
Wisconsin Early Sweet
Wisconsin Perfection __ _
Resistant Alaska X Surprise
Original cross, Arthur X Per-
fection, and backcrossed
to Perfection.
Horal X Prizewinner
do _
do-_ _.
do
High quality and vigor; resistant to
wilt.
Vigor; high quality; resistant to wilt.
more earlier than Perfection in ma-
turity; fully resistant to wilt.
TOMATO
©
©
California..
Georgia
Illinois
Tomato.
.do-.
.do..
.do..
...do..
— do-
...do..
_do....
.do— .
Pearson
California 55
Hastings Everbearin
Scarlet Globe.
Lloyd Forcing.-
Blair Forcing
Urbana Forcing
Sureset Forcing
Long Calyx Forcing
Illinois Pride
1936
1928
1932
1930
1936
1936
1936
1936
Fargo X California 55.
Santa Clara
Globe X Burpee
Louisiana
Rapids.
.do.
Pink X Grand
Marglobe X Grand Rapids..
Urbana Forcing X Blair
Forcing.
Lloyd Forcing X Marglobe-
New Century _
Hybridization.
Inbreeding
Hybridization-
Crossing followed by selec-
tion.
do-
do _
do
do—_
Selection-
Determinate vine, tough skin, intense
color.
Smooth fruit, high yield, intense color.
Resistant to fusarmm wilt and leaf
diseases; tolerates hot weather and
drought better than most varieties.
Wilt-resistant greenhouse type.
Do.
Do.
Do.
Do.
Wilt-resistant canning type.
do
§5 Indiana
do _
do
£ Louisiana
0
do
1
CO
T5 Maryland
do
do -
K5
CO
do
do
... do.
.... do
Minnesota...
do ,
do
' New Jersey
do _
New York (State)
do
do
North Dakota
do
do
do
do
do
do
Ohio
do
do _
do. _
do
do
do
Puerto Rico.
do
Early Baltimore
Prairiana
Illinois Baltimore
Indiana Baltimore
10-4
Maryland Canner
Maryland Slicer
Hybrid No. 4
Waltham Forcing
Michigan State Forcing
John Baer.-.
533
29-35
Rutgers _
Geneva John Baer
Nystate
Red River
Bison
Fargo Yellow Pear
Pink Heart
Golden Bison
Early Jumbo
Farthest North
Marhio
Nittany
Matchum
Penn State Earliana
Penn State
LJX-7
1936
1930
1936
1919
1936
1928
1930
1932
1931
1935
1926
1935
1936
1934
1930
1935
1925
1929
1932
1932
1932
1929
1934
1922
1922
1935
1935
.do
Selection out of a mutation or
accidental cross.
do
Louisiana Pink X Walter
Richards
Crossing and back-crossing;
growing plants on wilt
plots.
timore.
Greater Baltimore X San Jose
Canner.
do
Single-plant selection _
Single-plant selection
Viking X Bonny Best. _ __
do
Marglobe X J. T. D
do
Ponderosa X King Humbert
do
Red River X Cooper Special
Bison X Yellow Pear
do
do
Bison X Ohio Red
do _
Bison X Golden Queen. . .
June Pink X Globe
do
do _.
Bison X Red Currant
do -
Enormous X Yellow Pear.
Hummer X Matchless
do
State Earliana.
Louisiana Pink X native
do
Wilt-resistant canning type, especially
adapted to high-nitrogen prairie soils.
Do.
A wilt-resistant Baltimore.
High yield; foliage protection, resulting
in better color.
Few small seed. Resistant to wilt and
somewhat resistant to early blight;
pink; adaptability to Louisiana con-
ditions.
Solidity of flesh.
Do.
Do.
High yield, sets fruit under adverse
conditions; good color.
Self-pollinating, high quality, wilt
resistant.
High yield, good market and canning
qualities.
Early, productive.
Early, high color and fruit quality.
Inside color ripens from center; flavor
for juice.
Earliness, deep red color.
Earliness, large size, smooth fruit, deep
red color.
Earliness, smooth form, early.
Adapted to Great Plains area.
Early, determinate, heat resistant.
Adapted to Great Plains area.
Early, determinate. Adapted to Great
Plains area.
Do.
Do.
Early, large size. Adapted to Great
Plains area.
Extreme earliness. Adapted to Great
Plains area.
Resistant to fusarium wilt. Scarlet-
red fruit, productive.
Yield and uniformity.
Do.
Earliness, uniformity, yield.
Earliness, shape, and uniformity of
fruit and yield. Determinate foliage.
Tolerance to bacterial wilt.
ft
ft
£
fcs
ft
ft
ft
to
X
OS
4n
Table 4.— Improved varieties and strains of vegetable crops, peanuts, and sweet corn developed and released by State and Federal research agencies — Con.
T O M A T O— Continued
On
California..
Station or
U. S. Department
of Agriculture
Crop
Variety name
Date
intro-
duced
Parents
Breeding method
Superior characters
Tennessee.. ..
Tomato ...
Tennessee Pink
Fusarium wilt resistant.
Do
do
Tennessee Red
1912
1917
1918
1918
1918
1922
1924
1924
1925
1931
1932
1935
1930
do
Department
do
Do.
Fusarium wilt and nailhead resistant.
do
do
do
do
Merveillede Marches. __ ...
do
do
Columbia
Arlington _. .
do...
Norton X Duke of York
Marvel X Earliana.
. do
Do.
Norduke . .
do
do
do
Marvana
. do
Do.
Marvelosa
do .
Marglobe
Globe X Marvel
do
Do
do
do
do
Break o' Day...
do
Do.
Fritchard!
Cooper Special X Marglobe.
Globe X Marvel
... do
Qlovel!
and cracking.
do
Bonny Best X Best of All...
do .
.Hybridization
do
Heavier producer than parents. Good
shipper.
Heavier producer than parents.
do
Seedling No. 50
CUCURBITS
Watermelon
do
do
do...
Bush squash
Cantaloup 3
do
do..
do
Honey Dew melon.
California Klondike
Long Mountain
Striped Klondike
Resistant Klondiko No. 7.
Grey Zucchini No. 1
Powdery Mildew Resist-
ant Cantaloup No. 1
Powdery Mildew Resist-
ant Cantaloup No. 50.
Powdery Mildew Resist-
ant Cantaloup No. 50-
15.
Powdery Mildew Resist-
ant Cantaloup No. 45.
Powdery Mildew Resist-
ant Honey Dew No. 60.
1933
1936
1936
1936
1936
1931
1931
1932
1933
1935
1934
Klondike
Stone Mountain
Striped Klondike
Iowa Belle X Klondike..
Zucchini
Resistant variety from In-
dia and several commer-
cial varieties.
do
.do..
Hale Best X unfixed variety
from India.
Unfixed variety from India
X Honey Dew X Honey
Ball.
Inbreeding.
.do..
.do..
Hybridization-
Inbreeding
Hybridization..
-do..
.do..
.do..
.do-
Uniformity, flesh color, edible quality.
Oblong type, adapted to shipping.
Uniformity, high sugar.
Wilt resistant.
Early, productive, small, single-stem
plant.
Resistant to powdery mildew.
Do.
Do.
Resistant to powdery mildew, edible
quality. Superior shipping quali-
ties.
Resistant to powdery mildew, edible
quality.
3
to
©
©
Connecticut (State).
Florida
Iowa.
Mary land-
Michigan. .
Minnesota.
New York (State).
North Dakota
Department
Vermont
Squash..
.do.
Watermelon..
.do..
.do..
do
Squash
Muskmelon
Cucumber, pick-
ling.
Squash
.—do
—.do
Cucumber
Watermelon-
Cucumber
Squash
Cantaloup *.
Watermelon-
Squash
ConneeticutStraightNeck
African..
Leesburg..
Iowa King
Iowa Belle-
Pride of Museatine..
Des Moines
Maryland Gem
National Pickle
Kitchenette
New Brighton.
1.35
454.35
Northern Sweet-
Geneva
Buttercup-
Conqueror
Vermont Hubbard.
1935
1930
1930
1930
1928
1929
1930
1932
1935
193.5
1932
1929
1911
Straight Neck Inbred X
Giant Summer Crook
Neck.
Kleckley Sweet.
Conqueror X (?)
Conqueror X Kleckley
Sweet.
Kleckley Sweet
Des Moines
Buskirk's Gem _
Snow Pickling
Green Hubbard-
do
Buttercup
Arlington White Spine X
Bochford Market.
Quality X Essex hybrid (?)
(natural cross).
Eden X Stock citron.
Hubbard
.do-
Introduction.
Pure-line selection on wilt-
infested soil.
Hybridization..
do _
Selection
Inbreeding
Selection
Single-plant selection, mass-
ing of selfed lines.
Inbreeding _.
do
—do
Introduction and inbreeding
do _.
Hybridization _
Inbreeding.
Hybridization .
Inbreeding
Early, productive, uniform, smooth.
High quality and yield in Florida; some
resistance to stem borers.
Besistant to fusarium wilt in Florida.
Eesistant to fusarium wilt.
Do.
Do.
Uniformity and quality.
Thick, yellow flesh, quality.
High yield, superior pickling quality.
Uniformity, family size.
Uniformity, large size.
Early, high quality, family size, stores
well.
Early, productive pickling type.
Early, high quality, productive.
Parthenocarpic.
Convenient size, high quality; easily
prepared.
Resistant to fusarium wilt.
Improved uniformity and culinary
quality.
3
g
to
CO
b
SWEET CORN
Connecticut (State) ...
Sweet corn..
.do....
.do—
.do
.do— .
.do— .
.do.
.do.
_do„
-do.
.do.
.do.
-do.
-do_
Spancross C2
Spancross P39...
Marcross C6
Marcross C13.6..
Marcross C13.2..
Marcross P39—
Whipcross C6.2-
Whipcross C7.2..
Whipcross P39.02..
Whipcross P39
Rcdgreen..
M. Spanish Gold..
M. G. E. Market.
M. Whipple
1933
1933
1933
1935
1935
1935
1933
1933
1933
1926
1935
1935
1935
Spanish GoldXC2...
Spanish Gold X P39-.
G. E. Market X C6._
C13XC6.
C13XC2.
G. E. Market X P39__
C6 X C2-
C7 X 02..
P39 X 02
Whipple X P39..
C78XC77—
Spanish Gold__
G. E. Market.
Whipple
Hybridization..
_do.
.do.
.do.
.do.
.do.
.do.
_do_
.do.
.do.
do
Synthetic variety.
do
do
2 In cooperation with Florida station.
3 In cooperation with U.S. Department of Agriculture.
First early hybrid, large ear; resistant
to bacterial wilt.
Second early, resistant, good quality.
Very large ear; first early, resistant.
Do.
Do.
Second early, very large ear, good
quality, resistant.
Midseason, large ear, resistant.
Midseason, large ear, narrow kernel,
quality.
Midseason, large ear, resistant to
bacterial wilt.
Midseason, large ear, good quality, re-
sistant.
White, good quality, sun rod leaves.
Very early, parent of first early hybrid.
Early, resistant to bacterial wilt.
Midseason, resistant to bacterial wilt,
* See California, above.
Table 4. — Improved varieties and strains of vegetable crops, peanuts, and sweet corn developed and released by State and Federal research agencies — Con .
SWEET CORN— Continued
*>■
CO
Station or
TJ. S. Department
of Agriculture
Crop
Variety name
Date
intro-
duced
Parents
Breeding method
Superior characters
Sweet corn
.... do.
Florida No. 191-
1934
1935
1935
1935
1925
U925
1935
1935
1935
1935
1935
1935
1935
1935
1935
Country Gentleman, Cuban
Flint, Loveless, Pope,
and Stubbs.
Southern Snowflake %,
Long Island Beauty K.
Narrow Grain Evergreen
do
Country Gentleman
Hybridization, inbreeding,
bulk crossing of inbreds
and selection.
Hybridization and one back-
cross to Snowflake, selec-
tion.
Best open-pollinated strains
first selected by ear-row
methods, followed by in-
breeding and a high degree
of selection within each
line, then tested out in
numerous crosses,
do
ity.
do
Illinois Narrow Grain
Evergreen:
Inbred No. 13 -.
good quality.
do
._ _do.
commercially in 1937,
Do.
do__-
do
Country Gentleman
Narrow Grain Evergreen__
Illinois Country Gentle-
man:
do... .
adaptability to Illinois.
Do.
do
do
Country Gentleman
do
do...
Same as for Illinois Narrow
Grain inbreds.
Yield, uniformity, canning quality,
adaptability to specific Illinois con-
ditions.
Do.
do.-
Inbred No. 3
Do.
.. . do__
Inbred No. 5 . .
Inbred No. 6
„.do ..-
Do.
.-..do...
do
Do.
do
Inbred No. 8 . __....
do._
Do.
do.-
.. do
Inbred No. 9
do... .
Do.
..do...
Do.
do
do
Do.
do..
..do
Same as for Illinois Narrow
Grain inbreds.
Do.
do...
1920
1924
1928
1935
Stowell Evergreen X John-
son County White.
Golden Bantam x Gill's Ear-
ly Market.
Sunshine X Pickaninny
Black Beauty X Jap Hulless-
Productivity.
Earliness, size, quality.
North Dakota _
do
do
Popcorn _-
Hybridization, selflng, fol-
lowed by selection and
close breeding but not
selfed.
do.-_
Hybridization and selection.
Pinkie
Novelty.
8
ha
©
©
Co
Texas.
Department fin co-
operation with In-
diana station).
Department (in co-
operation with
Puerto Rico).
Sweet corn
do....
do.-_
do..
Surcropper Sugar.
Honey June
Golden Cross Bantam.
U. S. D. A. 34
1933
1933
1932
1935
Country Gentleman X Sur-
cropper.
Country Gentleman X Mex-
ican June.
Purdue 39 X Purdue 51
Native field corn and sweet
mutation of native sweet
corn.
Crossing and backcrossing
repeatedly to field corn
parent.
do
Hybridization.
Alternate generations of
selfing and backcrossing on
native field corn. The
final crossing was a double-
top cross between 2 second-
generation inbred lines
and 2 ear-to-row selections.
Earworm resistant, adapted to certain
southern conditions.
Do.
High yield, excellent quality, resistant
to bacterial wilt, uniformity of type
and maturity, high production of
stover.
Resistant to corn stripe. Thick,
tightly clasping husks. Vigorous
plant, size similar to field corn.
Large ears with kernels of unusual
depth.
ft
fcq
£
fcq
fcq
to
MISCELLANEOUS CROPS
Ohio.
Massachusetts.
California
Colorado.
Texas
Virginia (in coopera-
tion with Depart-
ment).
Department
Connecticut (Stated-
Louisiana.-
Massachusetts.
New Mexico...
Beet.
Carrot.
Onion..
do...
do...
Peanut. .
do__.
do..
Pepper..
do..
do..
do._
do..
.....do..
.do.
.do.
1932
1923
1935
1935
1936
1925
1935
1925
1936
1934
1936
1936
1935
1935
1935
1917
Inbreeding and sib-mating. .
California Early Red, U.
California Early Red
C. No. 1.
Inbreeding, massing large
numbers of similar unre-
lated lines.
No. 1.
Station No. 6.
Experiment Station
Jumbo
Jumbo.
Spanish 18-38
.. do
California Wonder XBounti-
ful.
Best local stocks of Red
Cayenne.
Bacon Rouge Cayenne
Native Sport X Honka (Jap-
anese variety).
Best local stocks of Tabasco__
do
Baton Rouge Cayenne...
C-2811 (not yet named)
Inbreeding and selection
Fi backcrossed to Honka to
intensify red color.
T-10-1 (Tabasco)
T-10-2 (Tabasco)
do
Waltham Beauty. __ .
Chile No. 9
Mexican Chile.
do
Dark color, round shape, absence of
light rings.
Long, smooth root; high yield.
Uniform size, shape, color, time of ma-
turity, keeping quality.
Flesh color, scale color, keeping quality,
fertility.
Yield uniformity; better storage; im-
proved color.
High yield, early maturity, high oil
content.
Very large pods and nuts; hard hulls.
Superior yielding capacity.
Early, productive; thick wall.
Size, uniformity, color, pungency and
yield.
Earliness, pungency; yield; resistant to
defoliation by Cercospora capsici.
Uniformity; productivity and superior
color.
Uniformity; productivity; color; ease
of harvesting.
Uniformity; fruit color and wall thick-
ness; ease of harvesting.
Thick fruit; early; high yield.
Improved adaptability, uniformity
yield and quality.
» Released first to Illinois Canners Association in 1933 and to seedsmen in 1935.
to
Table 4. — Improved varieties and strains of vegetable crops, peanuts, and sweet com developed and released by State and Federal research agencies — Con. ^
MISCELLANEOUS C R O P S— Continued
Station or
Ij. S. Department
of Agriculture
Crop
Variety name
Date
intro-
duced
Parents
Breeding method
Superior characters
Shallot
1936
1935
1935
1928
1919
1930
1926
1930
1936
Crossing and selecting desir-
able Fi plants.
Sweetpotato.. .
do
do
vigorous plants.
do
do. -.
per unit and 20 percent higher yield
than parent stock.
North Carolina
Porto Rico N. C. No. 1...
Hill and tuber selection
Introduced from Puerto
Rico.
Introduced from Japan
Introduced from Java. - ..
do.._
high in starch; ideally suited for
starch manufacture, and for live-
stock feed.
do
color; uniform appearance.
High quality; good keeper and yielder.
do
do._
do
do
sarium batatatis and F. hyperoiy-
sporum.
do.._
Kioranda Dutch Yellow. __
Puerto Rican Beauty...
do. _.
A-4 X University...
F. batatatis.
Do.
Table 5. — Outstanding vegetable strains, varieties, and breeding lines of practical or theoretical interest that are in the cultures
of State and Federal research agencies
BEAN
Station or
U. S. Department
of Agriculture
Crop or type
Variety name or no.
Date obtained
or started
How obtained
Parents
Characters of interest
W-80
1934
Hybridization
Corbett Refugee X String-
less Refugee.
Brittle Wax X White Ref-
ugee Wax.
Hybrid Wax U. S. No. 53C
X Corbett Refugee.
White Wax No. 122
Wax No. HO
high productivity.
White seeded wax bean of Kidney
Wax type.
do
Semineld
1935
do
Burtners Blight Proof...
1934.-
Introduced by Mr. Burt-
ner, of Wasco County,
Oreg.
to common bean mosaic.
Resistant to curly top.
to
©
©
Co
Illinois..
Iowa
Minnesota
New York (Cornell) .
Department (in co-
operation with Or-
Department (in co-
operation with Colo-
rado).
Lima
do
do
do
Green
White pod.
Henderson Bash, 11 lines.
Wood's Prolific, 4 lines..
Baby Potato Lima, 6
lines.
Large-Podded Hender-
son Bush, 9 lines.
Wholegreen
Fusduli..
About 100 lines.
Corbett Refugee
N1092
N675. -
Numerous other lines..
(•)-.
1930
1932
1915 to date.
1928 to 1935..
1931....
1935.
1933.
Mostly since
1930.
Selection and crossing..
Selection
.do..
Cross between two selec-
tions.
Hybridization
....do
Introduced
Numerous unnamed {
lings.
Hybridization-
Selection from Sioux City
Seed Co.
Hybridization
.do..
Hybridization and selec-
tion.
Henderson Bush
Wood's Prolific—
Henderson Bush
do _
Burpee Stringless Green
Pod X Refugee.
Brittle Wax X unnamed..
Unknown
Hybrids of and selections
from Robust, Wells Red
Kidney, White Marrow,
Flat Marrow, Scotia,
and White Imperial.
ResistantXsusceptible va-
rieties.
Stringless Green Refugee-
Brittle Wax X Corbett
Refugee.
Pinto X Cranberry
Striped Creasback.
American and foreign
varieties.
Uniformity.
Under test in 1936 for commercial
value.
Henderson Bush vine and earli-
ness, with small thick potato
type beans crowded in pods.
Outyields Henderson.
Large-podded; early; productive
under Illinois conditions.
Straight, stringless pods.
Attractive pod color.
Seed characters.
Variously resistant to root rot,
blight; immune to mosaic and
to specific strains of anthracnose.
Curly-top resistance.
Mosaic resistant.
Excellent wax bean type, good
color and excellent pods.
Tolerant to bacterial blight.
Disease resistance and adaptation
possibilities.
£
to
ft
fcq
b
X
LEAFY CROPS
Imperial No. 152.. ... .
Imperial No. 615.. . .
In process
do
Selling individual heads
and roguing the increase.
....do
Imperial 152
Improved adaptation to Arizona
do
conditions and conformity to
varietal type.
Do.
New York No. 12 X Iceberg.
Improvement in resistance to tip-
1
1934.
1934
1934.
1934.
1932
burn.
Appears to show superior ability
do.
do .
6—
do
do —
do
—do
do
to develop hard head under cer-
tain growing conditions.
Do.
15
Do.
do
do
26
do
Do.
5 United States commer-
cial varieties.
Mignonette is good parent because
of excellent heading under warm
conditions. Hybrids of Cali-
fornia commercial varieties with
Mignonette show promise.
■ Started 1930. Best lines of 1936.
Table 5. — Outstanding vegetable strains, varieties, and breeding lines of practical or theoretical interest that are in the cultures
of State and Federal research agencies — Continued
LEAFY CROPS— Continued
Iss
Station or V. S.
Department of
Agriculture
Crop or type
Variety name or no.
Date obtained
or started
How obtained
Parents
Characters of interest
Brassica hybrids. .
..do
1-35..
1935
Brussels sprouts— cabbage
hybrids.
do
Gives promise of forming head and
14-35
1935
do
sprouts.
Give promise of being an early
Crucifer hybrids..
Cabbage.. .
do
54.35 Fertile Hybrid
Numerous strains. _ .
Numerous lines
1930
1919 to date..
...do
Radish X cabbage
Homozygous for various
factors and characters
as purple, magenta, sun
color, and green; waxy;
dwarf types; and others.
Intertype crosses of Bras-
sica oleracea: cabbage X
cauliflower, brussels
sprouts, kale, kohlrabi,
wild cabbage.
Golden Self-Blanching X
Utah.
type of brussels sprouts.
Generic hybrid of scientific interest.
May serve same purpose as rape.
Breeding stocks for practical or
do
theoretical work.
For genetic study.
Self-blanching, good quality; re-
Lettuce..
do
.do
1929...
1929.
1929 and 1932
1929
1930...
1930 -
do
do
do
do
do -
. do
sistant to fusarium yellows.
Mignonette X Hanson
New York X Hanson
Mignonette X New York-
strains.
High quality; early maturity.
do
do
do
do
do
MN-29-8-7
types for eastern conditions.
P-1H-1190-3
IP-30-1-20
Tipburn resistant; high edible
MN-P-1193
1931
1931 . ...
do
do
quality.
Imperial CX hybrid
do
21ines C-NH-154.
1931
do
do
do
1931
.. do
4 lines MN-NH-150
NT-12-1
1932
. do
do
do.
do...
(!)
1928
do.
New York X Transport- ~
California Cream Butter X
Deacon.
temperature conditions.
Genetic material for chlorophyll
BD-3-1.
1928
do
deficiency.
Cos type.
do
do
M ....
Red CCRRTT.
B.._
...do.... -
California Cream Butter ..
Spotted CCt't'TT.
do
I
do
Tinged CCttTT.
do
H ._
do
Hanson
Green CCRRtt.
s
s
to
to
o
©
Department (in co-
operation with Wis-
consin).
do..
do..
do-
do..
do..
C —
NO
MN
77 lines homozygous for
resistance to yellows.
1930.
.do.
_do_.
.do-
Hybridization
do
Pure-line selection.
New York
Transport
Ohavigne
New York X Ohavigne.—
Mignonette X New York.
Smith Pride variety
Green ccrrTT.
Green CCr'r'tt.
Green CCrrtt.
Green ccrrtt
Green ccEBTT.
Useful for outcrossing to individ-
uals selected for resistance.
p
EA
Hybridization and pure-
lining.
Hybridization and selec-
tion.
..do .
Commercial varieties
Laxlon Progress X Giant
Stride.
do
1928.
1932-.-
1932
eration with Cali-
fornia).
Hundredfold type.3
pisi. Tolerance to unnamed
Kusaria found at San Luis
Obispo.
do
Mostly since
1932.
do
do
do
...do
do
do
do..... . .
do. .
Hybridization
do
. ...do
do
do....
do....
do
do
do .
Little Marvel X World
Record F4.
Laxton Progress X Nain
Mangetout F4.
Laxton Progress X Giant
Stride F5-F8.
Laxton Progress X World
Record.
Laxton Progress X Kent
Alderman.
Laxton Marvel X (Thomas
Laxton X Phenomenon).
man.
Austrian Winter X Hun-
dredfold.
Austrian Winter X Perfec-
tion.
Little Marvel X Progress
Fi-Fa.
do
do
do
do
do
do.—
15 strains—
6 strains
132 strains ..
4 strains _
30 strains .
15 strains
Axcochyta.
Resistant to certain viruses. Freez-
ing types, seed setting.
Size of pod, hardiness.
Resistant to fusarium wilts.
Pod size, seed setting.
Pod size, hardiness.
do
do __
do
ing types, seed sol, resistant to
fusarium wilts.
Genetics and breeding for resistance
to Ascochyta and MycosphaereUa.
Do.
Do.
do
do_.
. . do -
Pimm elatius
do. -
do-
Not fully explored.
3 strains. ... _. ...
do
do- .
do
- do.. .
Subspecies of P.
sativum.
Edible-podded
Pure lines and
varieties.
Do.
do
... do—. .
Do.
300 strains
do
do
Do.
^1
fcq
fcs
r
to
s Homozygous „ .
3 It is planned to
for anthoeyanin pigment in leaves of lettuce maintained at the Beltsville station,
these as soon as increased sufficiently.
Table 5. — Outstanding vegetable strains, varieties, and breeding lines of practical or theoretical interest that are in the cultures
of State and Federal research agencies — Continued
TOMATO, EGGPLANT, AND PEPPER
in
Station or U. S.
Department of
Agriculture
Crop or type
Variety name or no.
Date obtained
or started
How obtained
Parents
Characters of interest
1936„
1936
Red Currant X commer-
cial varieties.
Commercial stocks.
Perfection Pimiento
...do
spotted wilt.
Uniform type for variety.
Georgia _ ..
1928...
7-1-1
1920
.do ...
..do.
1926 .
Hybrid; line selected for
resistance to wilt and
leaf diseases.
Above backcrossed to
wilt-resistant strain of
Globe.
do_
.-do
do _.
—_do
.....do.
do _.. .
do _..
do.
do
22-3-1 _
1932
(Globe X Burpee) X Globe-
Globe selection X Break
o' Day.
Earliana X Best of All
Obscure. Hybrid be-
tween a wild currant
type and a commercial
variety.
drought.
Do.
2-3-1-1
1932.
Iowa ...
79--. ._.
Hawaii __ ...
Hawaii station hybrid. .
TXnited States commer-
cial varieties.
2 local wild currant to-
matoes.
Strain of Red River
No. 44-9.
1918
Horticulture department-
Introduced .
1932-35
fly (Badrocera cucurbitae) but
has small size.
Maryland
1930
Selection... .... _ ... ___
Breeding; introduced
Minnesota
1930-33
1935.. .
Early; productive.
Missouri. .
Lycopersicon pimpinelli-
folium X L. escu-
lentum hybrids.
Lycopersicon plmpinellifo-
lium X L. esculmtum.
New Hampshire
do
and inheritance of resistance.
Dwarf Purple X Black
Beauty.
Crossing and selection
... do—
Marglobe X 3. T. D
Break o' Day X Oxheart—
Marglobe X Earliana
Earliness; adaptability to Northern
States.
Undergoing selection for improved
yield, fruit shape, color, and
general high quality.
Do.
Marglobe X J. T. T>.
crosses.
Break o' Day X Ox-
heart crosses.
Marglobe X Earliana
crosses.
do
do _
. .do
Being selected for larger, smoother,
high-quality, early market to-
mato.
to
©
©
Ho
do
.—do
Usual commercial vari-
eties.
B-l
1935.
Large Cherry X Bonny
Best.
Gulf State Market X
Cherry.
do—
do
do-
do
do -
..do
377 ...
1935.
do
ditions; prolific.
Department
50 Marglobe lines
1932.
ditions; prolific; free from "puff."
1925-35. _
1932
Marglobe and other com-
mercial sorts.
European varieties
American varieties.. __. .
Australian, South Ameri-
can, and Asiatic sources.
Lpcoperskon pimpineUi-
folium X L. esculentum
and reciprocals.
wilt and nailhead resistant.
1932
1935-36
1935
do. _
ance work.
Do.
Do.
do
do
do-
do
do-
do
Hybridization and back-
crossing.
Do.
1932
Desirable type and fruiting habit.
High quality.
Early.
1930
U.S. Department of Agri-
culture.
North Dakota Agricul-
tural College.
U. S. Department of Agri-
culture.
do
1932
1930
Do.
1930-
Do.
A-4
1930
Black Beauty X Fajardo—
CUCURBITS
Cantaloup
do
Muskmelon
do
do
do
do
do
do
McDaniels Nugget
Superfecto
Hale Best
In process
do
1926-36
1926-36
1926-36
1926-36
1926-36
1926-36
1926-36
1930-36
1930-36
1930-36
Selfing individual plants
and rigidly roguing each
strain.
do
Inbreeding; 10-15 inbred
lines being carried along.
McDaniels Nugget
flesh, salmon color, deep net,
high sugar.
Do.
Commercial stocks
— lido— — HI— — "I "I
characters.
Do.
Do.
Do.
Do.
Do.
Many minor horticul-
tural varieties and sub-
species.
White Bush Scallop
Giant Summer Crook-
neck.
Giant Summer Straight-
neck.
10-15 inbred lines of each...
do
do
Commercial stocks
do
do
Uniformity of fruit and plant
characters.
Do.
Do.
do
do
ft
ft
s
to
t-<
ft
r
ft
to
i-i
X
'Other crosses: Marglobe X Stone, Argentina X Gulf State Market, Shanghai X Marvel, Cooper X J- T. D., Peiping X J. T. D , Pritchard X J. T. D., and others.
to
Table 5. — Outstanding vegetable strains, varieties, and breeding lines of practical or theoretical interest that are in the cultures
of State and Federal research agencies — Continued
CUCURBIT S— Continued
Station or U. S.
Department of
Agriculture
Crop or type
Variety name or no.
Date obtained
or started
How obtained
Parents
Characters of interest
California-
Squash
GreyZucchine
1930-36...
1933
10-15 inbred lines of each..
Uniformity of fruit and plant
characters.
Uniform fruit type; high sugar;
proline.
Do
Watermelon .
do
California Klondike No.
1.
California Klondike No.
3.
California Klondike No.
8.
Striped Klondike No. 11.
Thunnond Qrey No. 46__
Golden Honey No. 28...
Baby Delight No. 32 ...
Winter Queen No. 213—
Peerless No. 247
do....
1933.
do
do
do
1933... _
do.
...do
Uniform fruit type; tough rind.
Uniform fruit type; high sugar.
Uniform fruit type for variety.
Do.
do
do
do
do
1936
do
do
do— ._
do
do ...
1936
do _
1936
do
1936.
...do
Do.
do
do
1936.. _.
1936
do. _
..do—.
do —
do
do ...
Do.
Do
do
1936...
..do—
Do.
do
Chilean No. 7...
1936 .
do
do ...
Do.
do...
do
do
do
do
Snowball No. 12
1936...
1936
1936.
1936.
1936
do
do—
do
do _
do
do
do. -
do
do.
do .
Do.
Stone Mountain No. 44__
Long Mountain No. 216 .
Northern Sweet No. 251 .
Sun, Moon, Stars No. 265
Grey Monarch No. 260. .
Iowa Belle No. 542
Pride of Muscatine No.
136.
HybridNo. 7
Do.
Do.
Do.
Do.
do
do
do.
1936 _
1936-.
do
Hybridization
do—
Do.
1936
resistant to wilt.
Do.
do _.
1936
Klondike X Iowa Belle
...do...
Klondike type, resistant to wilt.
do
Hybrid No. 19
1936 _
do.—
do..
Hybrid No. 16
1936...
Klondike type, resistant to wilt.
Florida .
Cantaloup
Squash
1935
From Kilgore Seed Co
Plant Exploration and
Introduction, U. S.
Department of Agri-
culture.
1933
leaf spots.
Superior eating quality and yield-
ing ability; considerable resist-
ance to stem-borer.
Watermelon
do
Iowa Belle
1931
1931
do
under Florida conditions.
Do.
Improved Table Queen .
Isolation of high-yielding
inbred lines.
Increased uniformity and yield
and freedom from mixtures.
to
to
©
©
to
Louisiana
do _
Cucumber
do
Squash
Sugar Bowl
Crossing and backerossing.
Selflng
Scalloped White Bush X
Des Moines.
Windermoor Wonder. .
Maine.
1932
Line 128 _
1932.
do
Massachusetts
Blue Hubbard No. 1
Honey Bock inbreds
3=SS;2=S6
1935
Commercial Blue Hub-
bard.
Michigan
Muskmelon
do__
do
do
do
do
Cucumber
Muskmelon
Watermelon
Squash
Cucumber
Squash
do
1730 Fs
1935
Hale Best X Honey Rock..
(Hale Best X Honey Rock)
X Honey Rock.
HoneyDew X Emerald
Gem.
Honey Dew X Champlain
on Hearts of Gold.
1734 F2 _ ____
1935
do
1739 F6 _
1935
do...
4 Fs lines
1935 _..
do
Minnesota
Numerous strains
do
do __
do.._
Qranito State
1914-36
1932.
Introduction; selection;
inbreeding; hybridiza-
tion.
1934
Arikara, Northern Sweet,
Fordhook, Angelino,
Winter Queen.
1920-36
25-30 years ago.
1933
Introduction; selection; in-
breeding, hybridization.
New Hampshire
English X White Spine..__
Japanese Pie X Early Yel-
low Bush Scallop.
Japanese Pie X Mammoth
Yellow Bush Scallop.
Giant Summer Crook-
neck X Japanese Pie.
Quaker Pie X Banana
Japanese Pie X Delicata...
Bohemian (= Delicata) X
Japanese Pie.
American and oriental
sorts.
New York (Geneva)..
Cucurbita moschata X
pepo 31.
Cucurbita moschata X
pepo 32.
Cucurbita pepo X mos-
chata 43.
Cucurbita moschata x
maxima 52.
Cucurbita moschata X
pepo 64.
Cucurbita pepo X mos-
chata 70.
do_
do
do
do
do...
do
Muskmelon
1933__
do.
1933
do
1933
do
1933
do
1934 _
do
Department (in coop-
. .do
eration with Cali-
fornia).
Very uniform; deep teacup shape;
white color; very fleshy; sweet;
high quality.
Resistant to scab (Cladosporium
cucumerinum).
Do.
Uniform fruit; high yield; good
color; strain lacks roughness
desired by growers.
Some lines for hard shell and ropy
net.
Some lines for thick flesh and high
total solids.
Thick flesh of Hales and shell and
net of Honey Rock (not fixed as
yet).
More characters of recurrent
parent.
Orange flesh of Emerald Gem;
shell of Honey Dew.
Early maturing; green flesh.
Honey Dew.
Pure lines for several genetic
characters.
Resistant to fusarium wilt.
Early; seed color; quality.
Pure lines for several genetic
characters.
Excellent forcing cucumber; thirfty
grower; prolific.
Potential disease resistance.
Do.
Do.
Do.
Do.
Do.
Powdery mildew resistance.
3
ft
2
to
ft
ft
ft
ft
%
to
Table 5. — Outstanding vegetable strains, varieties, and breeding lines of practical or theoretical interest that are in the cultures
of State and Federal research agencies — Continued
CUCURBIT S— Continued
CO
Station or U. S.
Department of
Agriculture
Crop or type
Variety name or no.
Date obtained
or started
How obtained
Parents
Characters of interest
Department at Belts-
Cucumber
do
do
Mostly since
1930.
Japanese and Chinese va-
rieties.
American x Japanese or
Chinese varieties and
reciprocals.
American and oriental
varieties,
do... .
viile, Md.
50 lines. _
Do.
do
do....
20 lines
Do.
Chinese and Indian vari-
eties.
Chinese X American varie-
ties.
Some resistance to downy mildew.
Do.
do —
Squash
do
do
Muskmelon
do
do
do
Department at Cor-
1932
Uniform, productive, resistant to
curly top.
High quality, adapted to North-
west.
vallis, Oreg.
do
do _
Griffin
1933 _
Marblehead X Beau
Dessert.
Varieties of Cucurbita pepo .
1932 _,
Department at Chey-
1934
Early maturity.
enne, Wyo.
John the Gardener
Vine Peach
Hale Best _
1934-
1935 __
Tartness of flavor; early maturity.
1935-
do.
Squash and
pumpkin.
—-do— I— — —
New England Pie ..
Cocozelle
1930
do
Early, and good quality.
1930 __
do
Giant Summer Crook-
neck.
1930.
- .do.. .
Bush habit of growth; early.
Resistant to downy mildew.
Do.
Puerto Rico
Cucumber.. ..
do— -..
1933
35-2; 8-3-2
1935
Chinese Long X Early
Black Diamond.
S
to
to
©
©
Co
SWEET CORN
California..
Connecticut (State)-..
Sweet corn..
do
.-.do _
—.do
do
do
do
.—do
Dent corn..
_...do
....do
____do
Florida.
Sweet corn..
do
do
do
do
do
do
do
do
do
do
do
do
do
Papago
Honey June
California No. 1-
California No. 2..
California No. 3~.
Surcropper Sugar.
Florida 191.
Oregon Evergreen..
Mexican June
King Philip
Davis Prolific
Tuxpan
Connecticut 2_.
Connecticut 6.
Connecticut 7...
Connecticut 13_.
Connecticut 78..
Connecticut 77-
P39
P51
Sweet Snowflake.
Alachua Sweet.
Sweet Dubose--
Sweet Tuxpan.
Sweet Oklahoma Silver-
mine.
Sweet Trucker Favorite.
1934_.
1934..
1935-.
1935- .
1935..
1934..
1934..
1934-
1934..
1935-
1935-
1935-
1933..
1933..
1933-
1935.,
1926..
1926_.
1934..
1935_.
1935.
1935.
1935.
1935.
Associated Seed Growers,
Inc.
Texas Agricultural .Ex-
periment Station.
Hybridization
.do..
.do-
Texas Agricultural Ex-
periment Station.
Florida Agricultural Ex-
periment Station.
F. Lagomarsino
Aggelcr & Musser
F. Lagomarsino
Iteuter Seed Co.
Texas Agricultural Ex-
periment Station.
Inbreeding
.do..
.do..
_do_.
.do_.
.do-
Recurrent backcrossing.
do_-
_do_.
_do-
_do_.
_do.
Commercial stocks.
(Honey June X Oregon
Evergreen) X Honey
June.
(Honey June X Oregon
Evergreen) X Oregon
Evergreen.
(Honey June X Golden
Bantam) X Honey June.
Commercial stock..
do
do
do
Whipplc.
do....
-do-
Golden Early Market
Eed leaves (probablyfrom
Crosby).
Stowcll Evergreen
(?)
Golden Bantam___
Snowflake, Long Island
Beauty.
White Dent, Long Island
Beauty.
Dubose, Long Island
Beauty.
Tuxpan, Florida 191
Oklahoma Silvermine, Su-
wannee Sugar.
Trucker Favorite, Suwan-
nee Sugar.
Earworm resistant.
Earworm and heat resistant.
Earworm resistant.
Do.
Do.
Do.
Do.
Do.
Earworm and heat resistant.
Earworm resistant; yellow kernels.
Earworm resistant.
Do.
Dark green foliage, vigorous plant,
narrow kernel.
Light green foliage, resistant to bac-
terial wilt, broad kernel.
Narrow kernel, good plant and ear.
Very resistant to bacterial wilt.
Golden Early type of ear.
Good quality.
Large ear, good quality, pearly
white.
Good quality, adaptability; re-
sistant.
Good quality; 8-rowed ear.
Husk protection, southern type.
Do.
Do.
Husk protection; adapted to
Everglades.
Husk protection, southern type.
Husk protection, southern type;
earliness.
2
trj
tq
Co
b
Table 5. — Outstanding vegetable strains, varieties, and breeding lines of practical or theoretical interest that are in the cultures
of State and Federal research agencies — Continued
ON
©
SWEET C O R N-Continued
Station or U. S.
Department of
Agriculture
Crop or type
Variety name or no.
Date obtained
or started
How obtained
Parents
Characters of interest
Florida..
Illinois..
Sweet corn.
do
..do.
..do.
..do.
..do.
..do.
..do.
..do.
..do.
..do.
..do.
..do.
,.do.
.do.
..do.
.do.
.do.
Florida King Bantam.
22-507-806-4-104-203...
81-521-818-108-7-108-206
and 207.
84-528-110-9-108-209 and
210.
192-537-832-10-109-211
and 212.
202-544-838-113-12-111-
214 and 215.
203-545-839-13-112-216
and 217.
204-546-840-114-14-113-
218.
206-548-842-115-15-114-
219.
212-554-848-16-115-220
and 221.
5004-1A-1-1-19-4-121-226.
5020-1-1-1-129-234
5030-1-1-1-132-237
5041-1-1-1-134-239
5043-1-1-1-136-242
5044-1-1-1-137-243
5044-1-1-1-138-244
5050-1-1-1-141-247 and
248.
1935.
P)-
W-
P).
P)-
p).
(•).
P).
(=)-
«.
(')-
P).
(')-
P)-.
(«)-
p)~
P)~
Recurrent backcrossing..
Hickory King, Cuban
Hint, Suwannee Sugar.
Iowa State College No. 15
Evergreen X Yellow
Dent.
Open-pollinated Bantam
Evergreen.
Open-pollinated Whip-
ple's Early Yellow.
Purdue 1339-1-1-2-1-1-1-
Purdue No. 25
Purdue No. 29.
Purdue No. 34.
Purdue No. 38
Purdue No. 1313 X 1324...
Illinois No. 14 X Yellow
Wisconsin (589 31 X 3) X
Purdue (1339 X 1313).
Open-pollinated Bantam
Evergreen X (Purdue
1313 X 1319).
Purdue 1339-1-2-3-1-1-1 X
Iowa State College S
760-1.
Purdue (1308 X 1313) X
Purdue (1313 X 1335).
Purdue (1308X1335) X
Wisconsin 589 31 X 3.
Purdue (1308 X 1335) X
Wisconsin 589 31 X 3.
Purdue (1313 X 1324) X
Purdue (1339 X 1313).
Husk protection, southern type,
Golden Bantam ear type, tender
and very good quality.
(•).
S3
is
o
©
do
6051-1-1-1-249
(5)
Purdue (1313 X 1324) X
Purdue (1351 X 1313).
Inbred from Purdue 21 X
inbred from Purdue 29.
Inbred from Purdue (1308
X 1335) X inbred from
Purdue 34.
Inbred from [Wisconsin
(593 9 X 4) X Purdue(1339
X 1313)] X inbred from
Purdue 36.
Illinois Narrow Grain
Evergreen Xyellow
sweet.
do
do
do__ _
do.
5055-1-2-1-252 and 253...
5059-1-2-1-255
(J)
(!)..- -
5061-1-1-1-287
do._-
do
do...
5068-2-1-2-260 _
5068-4-1-1-262-.1 _-
5068-4-1-2-263, 264, and
265.
5068-4-1-3-266 and 267—
do _-.-
do
do._
do
5068-5-1-2-272 and 273- _
._ do
do
5068-5-1-4-275-
do
do.—
5088-8-1-1-276 -
do .
do
5068-8-1-3-278
do—.
do
1935-
Narrow Grain Evergreen
X Country Gentleman.
Superior yield
---do
.-—do _.
do
do
.. . do
a. b. 14 _
O. B. 51B-
1921'
1922'.
tion with Depart-
ment).
. do—
good quality.
Carries factor for high yield; tall,
CO. 22
C. G34.
1921? _
1931'
1928'
do
I doll~"-~-~. '.'. ......... _
Country Gentleman
_—~do— I———"-""-
slender plant. Good pollen
parent.
Resistant to kernel infection.
Produces an early top cross with
open-pollinated strains. Two-
ear type.
C. a. 6355—
do
do .
S. E.4-6
1921'..
do
S. E. V4
1928'-
..do
„ do
do.
N. Q. 119
1921' .
. . do.„.
Narrow Grain Evergreen—
do
do -
do
.... do.—
N. G. 1014-2-5
1921'.
do
sistant to ear rote.
Iogold 18.39
Crossing of inbred lines. _ .
do
Iogent 16.45; Iogent 90.45.
Iogreen 123.91; Iogreen
11.63.
Country Gentleman in-
breds.
Narrow Grain Evergreen
inbreds.
Do.
do
do
Do.
• Work started in 1929, and the lines listed are those showing merit as of 1935.
« These lines are all inbreds, the number of generations inbred being indicated by the number of integers in the pedigree. A great many additional inbreds are being maintained
(142 inbred lines in all), but only those showing distinct merit are listed. The object is to secure single crosses able to withstand the heat and drought of central Illinois and to show
a high degree of resistance to bacterial wilt. Purdue Golden Cross Bantam is not sufficiently resistant to wilt for the purpose. All the lines listed show promise. They range all the
way from extremely early 8-row to late-maturing 18-row types.
' First year of inbreeding.
2
to
fcq
X
fcq
to
X
OS
Table 5. — Outstanding vegetable strains, varieties, and breeding lines of practical or theoretical interest that are in the cultures
of State and Federal research agencies — Continued.
IS3
SWEET COR N— Continued
Station or U. S.
Department of
Agriculture
Crop or type
Variety name or no.
Date obtained
or started
How obtained
Parents
Characters of interest
Sweet corn
.. ..do
About 50 inbreds.
Mostly since
1930.
Hybridizing sweet X dent
corn followed by in-
breeding. Own produc-
tion.
Commercial and research
agencies.
Commercial varieties
New York (State)—
do -
G5
1927
High quality; potent hybridizer.
Pennsylvania
do
.. do.—
Purdue 39
1936—
From Glenn Smith, Lafa-
yette, Ind.
. .do.
1936
do—
do
do
do
do
. ...do
Purdue 13391-8-1
Purdue 1351-3-1-1-2
Purdue 3-1-3-2 -
1936.
do.—
1936
do
1936
...do
do -
Purdue 1308
1936
Purdue 8482.
1936
1936 _
do
do -
Purdue 14-1-2-6
MISCELLANEOUS CROPS
Asparagus
Beet
375 different plants, nos.
2-1 to 9-43.
1932
Mostly since
1930.
1934
Highly uniform inbreds
from commercial varie-
ties.
Selection and inbreeding...
Commercial varieties
known.
36-34,37-34
others of genetic interest only.
Commercial stocks
do. _
Through Plant Explora-
tion and Introduction.
do
do
Okra'
do — .
Stockton Yellow Globe
36-40.
Selfed one generation
Plant Exploration and In-
troduction.
Stockton Yellow Globe
(commercial stock).
P. E. I. No. 86279
Uniform; nonbolting.
do
do
1929
4-S4.
Stockton Yellow (com-
mercial).
Nonbolting.
to
©
©
-J
do — .
do ._
do
do
_ .do
Louisiana
Texas
do
do
do
do
...do
do—
do...
do .
_. . do—
do
do
.. do...
.... do...
.. . do
do
do
.. ..do
. . do...
tion with Depart-
ment).
eration with Vir-
ginia and South
Carolina) .
Hawaii .
Sweetpotato
do ---
do
do.
do
do
do
Italian Red 13-63
Italian Red (commercial)..
do
Inbreeding and selection
followed by intercrossing
similar lines and mass
open-pollination of sim-
ilar lines. (Stocks main-
tained at Louisiana.)
1935
1935 -.
1931 -
ish.
Pearl
1931
. do
1931
1931
do
do...
1931 -
do ...
1931
do
1931
do
1931
do .
1931
do
1931
do
1931
do...
Java P. L
1931
do .
H13-36-08. _ __
1934
Pearl X Carolina Runner.
Improved White Spanish
X Carolina Runner.
Improved White Spanish
X Virginia Runner.
H19-54-13-3
1935
do
H21-39-39
1934 ...
- do
1935
ginia Runner.9
Ahout 2S0 varieties and
introduction?.
Mostly since
1930.
1932-36.
1934 ._
Mostly by introduction.. _
Inbreeding, selection, in-
troduction.
Mostly through Plant Ex-
ploration and Introduc-
tion.
1922
do
1922...
do
1922 .
do....
1934
. do...
1922 ...
do ..
Pobrico
1934.... ._
do
Male sterile, mildew resistant.
Deep red; early.
Resistant to pink root.
Do.
Do.
Excellent keeping quality; high
total solids. Very strong flavor,
desired by certain markets and
processors. Adaptable to short-
day growing conditions.
Disease resistant.
Deep; nonsplitting.
Small, uniform seed of high quality.
White seed coat; poor quality.
Resistant to disease; high yield.
Resistant to disease; large seed.
Bunch; large seed.
Large seed; fairly resistant to
disease.
Bunch; large pods suitable for
roasting.
Resistant to disease; well filled.
Resistant to disease.
Resistant to disease; white seed.
Bunch; fairly resistant to disease.
Bunch; said to be resistant to
bacterial wilt.
Resistant to disease; fine hay.
Do.
Do.
Large pods; hard seed hulls and
superior yields.
Largely unexplored.
Improved color and quality.
ta
<n
s
ta
t-<
ta
ta
b
X
s Pure lines of the leading varieties are being maintained at the Louisiana station.
1 These selections have been placed in the hands of a selected group of growers for multiplication and distribution.
to
Table 5. — Outstanding vegetable strains, varieties, and breeding lines of practical or theoretical interest that are in the cultures
of State and Federal research agencies — Continued
MISCELLANEOUS CROP S— Continued
Station or U. S.
Department of
Agriculture
Crop or type
Variety name or no.
Date obtained
or started
How obtained
Parents
Characters of interest
Hawaii
Sweetpotato
do
do __
1917-22
1934 .
do
1934
do
do
do
do
do
1934
_. ..do
1917 .
do
40 Hawaiian varieties. -.
1917-35..
1926-29
1934
Collected from various
islands.
Hand crosses of known
varieties.
Seed collected in field;
open-pollinated.
do
...do _.
do __
do
do
do
do
do
40 open-pollinated seed-
lings.
Selection for eating quality is most
important object.
1923
Introduced from Java
do
Big Wig X(?) -
Department
do.
254
1923
1923
1923
Since 1919
Since 1919
Since 1935
do
do _
do _
From growers in United
States.
Foreign introductions
Open-pollinated seed
ance to Fusarium batatatis.
High starch content. Resistant to
Fusarium batatatis and F. hyper-
oxysporum.
291 _
do
About 25 varieties
About 30 numbers
About 100 seedlings
Of commercial interest in past or
at present.
Of potential commercial and breed-
ing value. Many are resistant to
Fusarium.
Do.
do.. _.
Female parent known.
s
S3
to
O
o
to
VEGETABLES— APPENDIX 365
Tablb 6. — Recent vegetable breeding activities of State and Federal agencies
in the United States
[Parentheses enclose names of investigators no longer connected with the institution!
State or department
and crop
Nature of studies
Personnel
Alabama:
Vegetables
Arizona:
Lettuce and can-
taloup.
California:
Asparagus
Cantaloup (part in
cooperation with
Department).
Celery
Onion
Peas
Squash (Cucurbita
pepo).
Spinach
Sweet corn
Tomato _
Watermelon
Colorado:
Bean (snap)
Lettuce
Onion
Connecticut:
Bean (lima)
Pepper...
Squash
Sweet corn
Delaware:
Cabbage
Florida:
Sweet corn. .
Tomato
Watermelon.
Georgia:
Peanut-
Tomato
Hawaii:
Lettuce
Sweetpotato.
Tomato
Idaho:
Bean
Searching the State for superior strains or plants
Selection within commercial varieties for local adapta-
tion.
Inheritance of spear size, shape, head tightness, tough-
ness, node size.
Inheritance of fruit size and qualitative characters,
resistance to powdery mildew. Effect of inbreeding.
Inheritance of pithiness and bolting __.
Inheritance of color of flesh, scale, foliage, seed; size of
seed; bolting; sterility. Cytology of Allium species
hybrids. Resistance to thrips.
(See Department cooperation with California)
Inheritance of fruit and plant characters and fruit
size. Effect of inbreeding.
Inheritance of resistance to mosaic.
Determination of factors governing earworm resistance;
nature of factor interaction in hybrid vigor by cross-
ing inbred lines.
Inheritance of fruit size; resistance to spotted wilt and
bacterial canker.
Inheritance of color of flesh, rind, seed coat; sugar con-
tent, rind toughness; size of seed; resistance to wilt.
Breeding for mosaic resistance and adaptability to
canning in Colorado.
Breeding for tipburn resistance by intervarietal cross-
ing and selection.
Inbreeding and selection in Sweot Spanish for im-
proved market type and adaptability to Colorado.
Selection for high yield
Inheritance of seedless character
Nature of hybrid vigor by crossing inbred lines
Development of early, disease-resistant, high quality,
productive new varieties and hybrids for canning
and market through use of inbreeding, hybridization,
and production of "synthetic varieties."
Inheritance of several seed, seedling, and plant char-
acters, and study of zygotic and gametic lethals.
Studies of hybrid vigor.
Inheritance of qualitative characters
Developing earworm-resistant sweet corn of good
quality adapted to Florida by intervarietal crosses,
backcrosses, and selection.
(See Department cooperation with Florida.)
Selection for wilt resistance
Inheritance of color of leaf and seed coat; growth habit;
size and shape of seed and pods; size and shape of
leaflets; resistance to cercospora leaf spots, Sclerotium
rolfsii and physiological seed spot. Hybrid vigor.
Intervarietal crosses for wilt resistance and adaptation
to Georgia conditions.
Hybridization and selection to obtain varieties that
will head well at low altitude in the subtropics.
Controlled hybridization, selection, and use of open-
pollinated seed to obtain high quality, yield, and if
possible resistance to weevil.
Intervarietal and species crosses and selection to obtain
resistance to melon fly. Resistance to late blight
and mosaic being sought.
Development of improved disease-resistant varieties
by intervarietal crossing and by pure-line selection.
Inheritance of resistance to common bean mosaic.
C. L. Isbell.
W. E. Bryan, M. F.
Wharton.
(H. A. Jones, G. C.
Hanna.)
(I. T. Kosa.i G. W.
Scott), I. C. Jagger,»
T. W. Whitaker.'
(S. L. Emsweller.)
(H. A. Jones, S. L. Em-
sweller.)
(G. W. Scott.)
Do.
(C. F. Poole.)
(0. H. Pearson), D. R.
Porter.
(J. T.Rosa,< G.W.Scott),
D. R. Porter 'C. F.
Poole).
A. M. Binkley.
Do.
Do.
D. F. Jones, W. T. Sin-
gleton, L. C. Curtis.
Do.
Do.
Do.
L. R. Detjen, E. W.
Greve.
F. H. Hull, W. A.
Carver.
M. N. Walker.
N. C. Woodroof.
H. L. Cochran.
(C. P. Wilsie), J. H. Beau-
mont, M. Takahashi.
Do.
Do.
W. H. Pierce, Leif Ver-
ner, G. W. Woodbury.
1 Deceased.
1 Of V. S. Department of Agriculture.
366
YEARBOOK, 1937
Table 6.-
-Recent vegetable breeding activities of State and Federal agencies
in the United States — Continued
State or department
and crop
Nature of studies
Personnel
Illinois:
Bean (lima).
Sweet corn.
Tomato
Indiana:
Tomato- --
Iowa:
Bean (snap)
Tomato
Sweet corn.
Louisiana:
Collard, carrot
okra, pepper.
Cabbage, onion...
Shallot, squash,
tomato.
Sweetpotato
Maine:
Bean
Cucumber
Tomato
Maryland:
Cantaloup, sweet
potato.
Pea
Spinach
Sweet corn
Tomato
Massachusetts'.
Asparagus
Celery -
Lettuce (coopera
tion with De
partment).
Squash.
Tomato
Michigan:
Beans
Brussels sprouts..
Intervarietal crosses and pure-line selection for im-
proved yield and adaptability to Illinois conditions.
Inheritance of rowing, nature of hybrid vigor in crosses
of inbred lines. Production of high yield and qual-
ity sweet corn for Corn Belt conditions.
Intervarietal crosses and selection for wilt resistance
in field and greenhouse types and adaptation to
high-nitrogen prairie soils.
Selection for wilt resistance and improved adaptability
to Indiana conditions.
Intervarietal crossing and selection for high-quality
beans adapted to Iowa.
Intervarietal crossing and selection for high-quality
tomatoes adapted to Iowa.
Nature of inheritance of specific qualitative factors,
determination of linkage relations, inducing and
studying inheritance of new variants, study oi poly-
ploid forms and cytology thereof.
Improving yield and uniformity through crossing of
inbreds developed from commercial varieties. In-
heritance of resistance to drought and bacterial wilt.
Inbreeding and selection to obtain strains of superior
market value and productivity adapted to Louisiana
conditions.
Crossing of inbred lines to attain objectives stated
above.
Crossing and backcrossing commercial varieties to
attain objectives stated above.
Hill unit selection and isolation of mutants to improve
stocks and obtain new sorts of specific value as for
starch manufacture.
Selection, crossing, and backcrossing to improve Yel-
low Bye type; development of blight- and anthrac-
nose-resistant sorts. Inheritance of eye pattern,
color, vine characters, seed size, and linkage relations.
Inbreeding and selection for resistance to Cladosporium
cucumerinum.
Selection for earliness and resistance to cracking
Selection for quality, yield, and adaptation _.
Selection for resistance to wilt ._
Mass selection for increased winter hardiness
Study of natural selection in successive generations of
sweet X dent corn cross. Development of vari-
eties and hybrid sweet corns from inbreds from sweet
X dent crosses. Studies of hybridization technique.
Hybridization and selection for quality, yield, and
adaptation.
Early work on selection for disease resistance.
Selection and crossing selected plants to study trans-
mission of yielding ability.
Development of superior strains of Pascal through in-
bred selections.
Hybridization and selection to obtain crisp heading
varieties and greenhouse types for Massachusetts.
Development of superior strain of Warted Blue Hub-
bard by inbred selections.
Hybridizing Lycoperskon pimpineUi/olium and L.
eseulentum to obtain leaf mold resistance.
Crossing and backcrossing varieties to obtain higher
quality, darker green, mosaic resistance, and better
pod-setting in canning sorts.
Inbred selections (greenhouse bud pollination) to
develop strains for upland and for muck soils.
W. A. Huelson.
Do.
Do.
E. C. Stair, (J. II. Mac-
Qillivray).
A. T. Erwin, E. S.
Haher.
Do.
E. W. Lindstrom
A. T. Erwin, E.
Haber.
J. C. Miller.
Do.
Do.
(P. M. Surface, K. Sax),
H. C. McPhee, (F. v.
Owen), I. M. Burgess,
(C. R. Burnham), R.
M. Bailey.
I. M. Burgess, R. M.
Bailey
R. M. Bailey.
T. II. White.
C. E. Temple.
(F. W. Geise,
Cordner.)
W. B. Kemp,
H. B.
R. O.
Rothgeb (A. Stabler).
T. II. White, J. B. S.
Norton.
Robert E. Young.
Do.
Do.
Do.
E. F. Ouba.
C. H. Mahoney, H. L.
Seaton, Ray Nelson,
Miriam Strong.
Do.
VEGETABLES— APPENDIX
367
Table 6.-
-Recent vegetable breeding activities of State and Federal agencies
in the United States — Continued
State or department
and crop
Michigan — Continued.
Colery
Cucumber
Muskmelon
Radish
Sweet corn.
Minnesota:
Asparagus..
Bean
Brasska spp -
Carrots
Cucumber
Cucurbits, other
(muskmelon,
squash, water-
melon).
Eggplant
Pepper
Rhubarb
Tomato
New Hampshire:
Eggplant _-.
Tomato ..
New Jersey:
Tomato
New Mexico:
Onion.. -.
New York (Cornell) :
Bean (chiefly field
types).
Cabbage .
Celery..
Lettuce (coopera-
tion with Depart-
ment).
Nature of studies
Inheritance of resistance to yellows..
Inbred selections for greater fruit length in National
Pickle.
Inheritance of netting and sterility. Honey Rock
inbred selections for hard rind and ropy net; for
thick flesh and high solids. Varietal crosses and
backcrosses involving Hale Best, noney Dew,
Honey Rock, Emerald Gem, Champlain, and
Hearts of Gold for improved quality, appearance,
and adaptability of specific new combinations of
characters.
Root selection for short top, uniformity, shape, and
color in Scarlet Globe.
Inbreeding, hybridization, and selection for re-
sistance to European corn borer, tolerance to bac-
terial wilt, and high canning quality. Develop-
ment of desirable inbred pollen parents.
Selection within Washington strains to improve yield
and study transmission of yielding ability.
Inheritance of several qualitative and quantitative
characters.
Genetic and cytological study of cabbage X radish
and Brussels sprouts X cabbage hybrids.
Selection of superior strains through inbreeding
Inheritance of a number of qualitative and quantita-
tive characters including plant height, determinate
growth, and study of shape correlations.
Varietal crosses and selection to develop fusarium wilt
resistance. Inheritance of qualitative factors in
squash.
Studies similar to those on cucumber -
Inheritance of several qualitative and quantitative
characters, studies of shape correlations.
Inbreeding, selection, hybridization for improving
petiole color and quality.
Inheritance of growth habit, time of ripening, fruit
size. Effect of polyploidy on economic characters.
Study of certain linkages.
Varietal crosses and selection to obtain earlier sorts
adapted to Northern States.
Selection of locally adapted forcing strains. Study of
hybrid vigor in intervarietal crosses.
Varietal crosses, backcrosses and selection for improv-
ing yield, color, and wilt resistance of canning types.
Selection of Spanish types for improved quality and
adaptability to the Southwest.
Hybridization of varieties followed by pedigreed selec-
tion for development of disease-resistant varieties.
Inheritance of resistance to specific diseases. Minor
attention to inheritance of other characters.
(Early work on inheritance of qualitative and
quantitative characters.)
Improving variety uniformity and quality by selection.
Developing new and superior combinations of
characters by hybridization and selection. Inherit-
ance of color, stem length, head shape, texture, and
flavor (odor) . Intertype crosses involving cabbage,
cauliflower, brussels sprouts, kale, kohlrabi, and wild
cabbage for cytogenetic study.
Inheritance of color; size, shape, and toughness of
petioles; resistance to yellows.
Selection within hybrid progenies and varieties for
improved heading, quality, and tipburn resistance.
Personnel
C. H. Mohony, H. L.
Seaton, Ray Nelson,
Miriam Strong.
Do.
Do.
Do.
Do.
(R. Wellington, J. W.
Bushnell, W. T. Tap-
ly), F. A. Krantz,
T. M. Currence, A. E.
Hutchins, assisted by
J. G. Leach, T. M.
McCall, T. S. Weir,
M. J. Thompson.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
J. R. Hepler, G. F.
Potter.
De.
L. G. Schermerhorn, 0.
M. Haensler.
F. Garcia.
W. H. Burkholder, R. A.
Emerson, A. L. Harri-
son, D. Reddick. (M.
F. Barrus, W.H. Burk-
holder, G.P.McRostie,
R. A. Emerson).
O. H- Myers, W. I.
Fisher.
R. A. Emerson.
J. E. Knott, (J. B. Hart-
mann.)
368
YEARBOOK, 1937
Table 6.-
-Recent vegetable breeding activities of State and Federal agencies
in the United States — Continued
State or department
and crop
New York (Geneva)
Bean (snap)
Cucumber
CumrbHa spp
Muskmelon
Pea
Squash
Sweet corn
Tomato
North Carolina:
Lettuce (coopera-
tion with De-
partment).
Sweetpotato
Tomato
North Dakota:
Bean
Muskmelon
Physalis (ground-
cherry).
Squash (Cucurbita
pepo).
Tomato
Watermelon
Ohio:
Beet
Cabbage
Lettuce
Tomato
Oklahoma:
Sweetpotato..
Pennsylvania:
Cabbage _.
Tomato
Puerto Eioo (Univer-
sity station):
Cucumber
Eggplant
Tomato
Puerto Eico (Federal
station):
Sweet corn
Nature of studies
Varietal crosses to obtain mosaic-resistant improved
sorts. Inheritance of mosaic resistance.
Varietal crosses to obtain improved greenhouse types_
Interspecific hybrids among C. maxima, C. pepo, and
C. mosdiota to determine specific limitations within
the genus and possibilities of developing new and
valuable combinations of characters, including dis-
ease resistance. Inheritance of mosaic resistance.
Hybridization to obtain earlier and higher quality
varieties.
Inheritance of root-rot resistance
Hybridization to obtain earlier and higher quality
varieties.
Development of new inbreds for production of superior
hybrid corns for canning and market. Chemical
studies of hybrids.
Selection and varietal crosses for improved canning
varieties adapted to the Northeast.
Selection within hybrid progenies and varieties for im-
proved heading, quality, and tipburn resistance.
Hill unit selection for improvement of varietal type
and yield.
Hybridization and selection for resistance to bacterial
wilt.
Varietal hybridization and selection to obtain earliness,
disease resistance, and improved regional adaptation.
Inheritance of earliness.
Hybridizing of American and foreign forms to obtain
earliness, size, quality, adaptation to the region.
Varietal crosses and selection to increase earliness,
yield, and improve yellow color.
Inheritance of hard rind, flesh color, rind color. Isola-
tion of better adapted strains through inbreeding
and selection.
Inheritance of uniform color, determinate growth, lo-
cule number, earliness, fruit size. Varietal crosses
and selection to obtain high yield, quality, and earli-
ness in northern Oreat Plains area.
Inbreeding and selection of heterogeneous foreign intro-
ductions to obtain varieties adapted to the region.
Sib mating of inbred selections to obtain superior color
and absence of zoning in cannery beets.
Inbreeding and selection to obtain more uniform and
productive strains of Golden Acre.
Selection for tipburn resistance in greenhouse strains
of Grand Rapids.
Selection of greenhouse strains of Marhio
Interspecific crossing and backcrossing to obtain
cladosporium resistance.
Hill unit selection in Nancy Hall and Porto Eico for
increased yield, uniformity, and typical shape.
Line selection for higher yield, uniformity, and better
storage quality.
Inheritance of skin and flesh color in the Orange to-
mato. Varietal crossing and selection for improved
earliness, fruit shape, uniformity, and yield.
Inbreeding, crossing, and selection for downy mildew
resistance and adaptation to tropical conditions.
Inbreeding, crossing, and selection for resistance to
bacterial wilt, for superior quality, and adaptability.
Hybridization of commercial and native varieties for
resistance to bacterial wilt and for improved adapt-
ability and shipping qualities.
Inbreeding, crossing, and backcrossing sweet and
native field types for resistance to stripe and to ear-
worms; for good quality and adaptation to the
Tropics.
Personnel
A. L. Harrison, J. G.
Horsfall.
W. T. Tapley.
G. P. Van Eseltine.
W. D. Enzie.
A. L. Harrison, J. G.
Horsfall.
W. D. Enzie.
P. V. Traphagen.
C. B. Sayre.
Robert Schmidt.
Do.
Do.
A. F. Yeager, D. H.
Scott.
Do.
Do.
Do.
Do.
Do.
I. C. Hoffman, H. D.
Brown.
Do.
Do.
Do.
L. J. Alexander.
E. F. Burk.
C. E. Myers, H. K.
Fleming.
Do.
A. Boque.
Do.
Do.
B. L. Davis.
VEGETABLES— APPENDIX
369
Table 6. — Recent vegetable breeding activities of State and Federal agencies
in the United States — Continued
State or department
and crop
Rhode Island:
Eggplant..
South Carolina:
Asparagus..
Bean.
Okra.
Sweetpotato.
Tennessee:
Tomato
Texas:
Onion.
Peanut-
Tomato.
Sweet corn.
Utah:
Celery
Onion.
Tomato-
Vermont:
Squash.
Virginia:
Bean
Peanut (cooperat-
ing with Depart-
ment).
Virginia (Truck sta-
tion) :
Kale
Spinach.
Washington:
Tomato. .
West Virginia:
Watermelon-
Wisconsin:
Bean...
Nature of studies
Broccoli (sprouting)
Cabbage (cooper-
ating with De-
partment).
Eggplant _
Onion (cooperat-
ing with Depart-
ment).
Pure-line selection, hybridizing varietal inbreds, and
selection to develop wilt resistance in good commer-
cial types.
Selection to obtain higher yield, uniformity, and adap-
tation to South Carolina conditions.
Intervarietal crosses and selection to obtain increased
yield, tolerance to mildew and mosaic, earliness,
tolerance to adverse growing conditions in South
Atlantic areas.
Pure-line selection for improved uniformity, quality,
yield, and spineless pods.
Hill unit selection for improved yield and uniformity-
Selection for fusarium wilt resistance
Selection for resistance to pink root and freedom from
splits.
Pure-line selection for increased yield, earliness, and
oil content of Spanish type.
Intertype and intervarietal crosses and selection to
develop freedom from puffy fruits. Inheritance of
tendency to pufflness.
Production of sweet corn adapted to Texas.
Selection for uniform type and resistance to wilt in
Utah variety.
Inbreeding and mass selection to improve yield,
uniformity of shape, and keeping quality in Sweet
Spanish.
Selection to improve uniformity and obtain wilt
resistance in Greater Baltimore and Stone types
adapted to Utah conditions.
Inbreeding Hubbard squash to improve uniformity,
quality, and yield.
Hybridization and selection for rust resistance, high
yield and quality. Inheritance of rust resistance.
Pure-line selection to obtain high yielding very large-
seeded strains of Virginia type.
rure-line selection for deeper green color and resistance
to cold.
Varietal hybridization and selection for resistance to
cold, heat, mosaic ("blight"), and quick bolting;
high yield and attractive savoy-leaved type.
Hybridization and selection to obtain early, locally
adapted sorts.
Inheritance of resistance to certain forms of Fusarium
niveum. Crossing and backcrossing nonedible
resistant and edible susceptible forms to obtain
edible resistant variety. Cytologlcal studies of
above material.
Hybridization and selection to obtain mosaic-resistant
snap beans of high quality and adaptation to Wis-
consin.
Mass selection for improved head size and uniformity..
Inbreeding and selection for yellows-resistant strains
of the several commercial types. Determination of
genetic nature and inheritance of different types of
resistance.
Inbreeding and selection for club-root resistance in
crucifers.
Hybridization and selection for increased size and
pcvT,lj npss
Hybridization and selection for smut resistance in
onions.
Personnel
T. E. Odland, F. K.
Crandall.
J. B. Edmond, L. E.
Scott.
J. M. Jenkins, Jr.
R. A. McGinty, P. S.
Andrews.
J. B. Edmond.
(S. H. Essary), C. D.
Sherbakoff, B. D.
Drain.
L. R. Hawthorn.
G. T. McNess.
J. P. Wood, L. R. Haw-
thorn, S. H. Yarnell.
P. C. Mangelsdorf.
A. L. Wilson.
Do.
Do.
M. B. Cummings, E. W.
Jenkins.
S. A. Wingard.
E. T. Batten, J. H.
Beattie.'
H. H. Zimmerley.
(I.. B. Smith), H. H.
Zimmerley.
C. I,. Vincent, L. K.
Jones.
(L. S. Bennett), T. C.
Mcllvane, J. A. Rig-
ney.
J. C. Walker, W. H.
Pierce.
O. B. Combs.
(L. R. Jones, L. M.
Blank), J. C. Walker.
J. C. Walker, R. H.
Larson.
0. B. Combs.
J. C. Walker, H. A.
Jones.
» Of U. S. Department of Agriculture.
370
YEARBOOK, 1937
TABLE 6. — Recent vegetable breeding activities of State and Federal agencies
in the United States — Continued
State or department
and crop
Nature of studies
Personnel
Wisconsin — Contd.
Pea. __
Radish
Tomato _..
Department of Agri-
culture:
Bean (snap and
field).
Bean (lima) .
Beet-
Cabbage...
Cucumber.
Lettuce
Muskmelon (in co-
operation with
California).
Pea (part of pro-
gram in coopera-
tion with Cali-
fornia, 1933-36).
Hybridization and selection for obtaining more pro-
ductive, higher quality, wilt-resistant peas adapted
to Wisconsin conditions.
Inheritance of rogues
Inheritance of resistance to fusarium wilt
Mass selection to improve uniformity and earliness of
Scarlet Globe.
Hybridization and selection to improve fruit size and
fruit setting under greenhouse conditions in winter.
Hybridization and selection among wide range of
types to obtain:
(1) Curly-top resistance in garden and additional
field types.
(2) Resistance to mosaic, rust, bacterial blight, and
loot rot in market, canning, and field types.
(3) "Multiple" resistance to all known strains of
anthracnose.
Inheritance of mosaic resistance (cooperative with
Wisconsin) .
Inheritance of resistance to rust, blight, and mosaic. .
Inheritance of plant habit and seed-coat color and pat-
tern. Varietal hybridization and selection to obtain
increased setting of pods in the large-seeded types;
increasing thickness and number of seeds per pod in
small-seeded types; increased earliness.
Development of highly self-fertile inbred strains of
good commercial type to improve uniformity and
facility of maintaining varietal or strain character-
istics.
Inheritance of a variegated red color in the root
Crossing garden and curly-top-resistant sugar beet,
and selection to obtain curly-top-resistant garden
varieties.
Inbreeding and hybridization and selection to obtain
a round, short-core, high quality, winter-hardy, non-
bolting variety for the South Atlantic and South-
eastern States. (See also Wisconsin, cabbage.)
Inbreeding and hybridization and selection among
American and Asiatic types to obtain good com-
mercial slicing and pickling varieties resistant to
mosaic, bacterial wilt, and downy mildew. "Mul-
tiple" resistance is ultimate object.
Hybridization among American and foreign sorts, and
selection to obtain:
(1) Resistance to brown blight and powdery mildew
and adaptability to numerous different specific
southwestern and Pacific coast conditions.
(2) Hard-heading properties, high quality, resistance
to tipburn and adaptability to eastern United
States conditions. (See also Massachusetts,
New York, and North Carolina, lettuce.)
Inheritance of different anthocyanin and green leaf
colors, seed color, chlorophyll deficiency, and tip-
burn resistance.
Inheritance of resistance to brown blight and mildew. .
Hybridization and selection among American and
Asiatic types to obtain varieties resistant to powdery
mildew and of high culinary and shipping quality
for the Southwest.
Inheritance of resistance to powdery mildew
Hybridization and selection among available peas of
the world that indicate the desired characters, to
obtain:
(1) Large-podded market types resistant to fusarium
wilt, to Aseoekyta, and to adverse climate.
(2) Resistance to certain mosaics.
1) r
(3) Resistance to root rot.
Inheritance of resistance to root rot, certain mosaics,
Ascochyta, and certain new fusarium wilts.
E. J. Delwiche (E. J.
Renard) .
(E. J. Renard.)
(B. L. Wade.1
O. B. Combs.
Do.
(W. W. Tracy, Jr.),i
B. F. Dana.
B. L. Wade, W. J. Zau-
meyer, C. F. Poole,
L. L. Barter.
C. F. Andrus.
(M. C. Parker.)
B. L. Wade, C. F. Poole,
W. J. Zaumeyer.
Roy Magruder.
Do.
Do.
B. F. Dana.
B. L. Wade, C. F. Poole.
W. S. Porte, S. P.
Doolittle.
I. C. Jagger, T. W.
Whitaker.
R. C. Thompson.
Do.
T. W. Whitaker, I. C.
Jagger.
I. C. Jagger, T. W. Whit-
aker, (J. T. Rosa' and
O. W. Scott, Califor-
nia).
Do.
B. L. Wade, W. J. Zau-
meyer (H. A. Jones,
California).
Do.
Do.
Do.
Do.
i Deceased.
VEGETABLES— APPENDIX
371
Tablk 6. — Recent vegetable breeding activities of State and Federal agencies
in the United States — Continued
State or department
and crop
Nature of studies
Personnel
Department of Agri-
culture—Continued.
Sweet corn
Sweetpotato.
Tomato (part of
program in co-
operation with
Florida).
Watermelon (part
in cooperation
with California).
Development of varieties and of inbreds for production
of hybrid corns. Objectives: High yield, uniform-
ity, quality, adaptation to the Corn Belt, resistance
to bacterial wilt, and specific kernel characteristics
adaptable to factory use. Inheritance of quality in
sweet X dent crosses. Inheritance of resistance to
bacterial wilt, and of albescence.
Hybridization and selection to obtain earworm resist-
ant varieties adapted to the Southeast.
Hybridization and selection as well as growing seed-
lings from open-pollinated seed to obtain variants of
higher yield, starch content, earliness, quality, disease
resistance or adaptability to specific environments.
(Cooperative with La Estacion Experimental Agro-
nomique, Santiago de las Vegas, Cuba; and Federal
Experiment Station, Mayaguez, Puerto Rico.)
Inbreeding and varietal and interspecific hybridization
and selection for resistance to wilt, nailhead, and
various leaf and virus diseases, and to cracking; for
high color, adaptability to shipping, and to specific
adverse environments. Inheritance of resistance to
wilt.
Study of seed size and color, flesh and skin color, size of
fruit, and growth habit. Resistance to wilt, leaf
diseases, weather conditions, and insect damage.
Q. M. Smith (in coop-
eration with Indiana).
C. F. Poole.
J. H. Beattie, C. E.
Steinbauer, W. K.
Bailey (Puerto Rico),
(C.deValle.Cuba).
W. S. Porto, F. L. Well-
man, B. L.Wade, C.F.
Poole, (W. M. Fifield,
Florida).
C. F. Poole, (D. R. Por-
ter, California).
Table 7. — Vegetable breeding and improvement ivork in foreign countries
Note.— The limitations of this very sketchy survey are recognized. Only a part of the world's vegetable
breeding activities have been referred to, and important activities have been unavoidably omitted. These
few notes, however, testify to the world-wide importance of many general problems and the determination
of plant breeders and vegetable growers to obtain ever better crop plants.
Country, institution, and
official
Nature of studies
Australia, Department of
Agriculture of New South
Wales, Sydney; H. Wen-
holz, director of plant
breeding.
Bean, broad-
Bean, snap— .
Beet, garden.
Beet, silver, or chard.
Cabbage, cauliflower,
brussels sprouts.
Adaptation studies of foreign introductions.
Hybridization and selection for higher yield, better
adaptation and resistance to bacterial blight,
anthracnose, mosaic, and dry root rot.
Canadian Wonder X Refugee H. 3263 (U. S. D. A.)
and Canadian Wonder X Murunga are promising
unfixed early disease-resistant hybrids.
Tweed Wonder X Keeney Refugee is a promising
fixed early blight-resistant hybrid.
New variety introduced: Hawkesbury Wonder,
from Tweed Wonder X Keeney Refugee.
Best yielding varieties are Canadian Wonder
(standard), Hawkesbury Wonder, Staley's
Brown Beauty, and Staley Surprise.
Location: Hawkesbury Agricultural College; Bath-
urst and Grafton Experim3nt Farms.
Selection in self-fertile and close-fertilized lines for
improved quality and yield.
Best lines to date are from Rapid Red, Ohio
Canner, and Detroit Dark Red (from United
States).
Location: Hawkesbury Agricultural College.
Selection, isolation, and testing of strains; self-
fertility being sought; to improve uniformity and
type of commercial varieties.
Superior strains isolated from local silver beet and
Lucullus. Begun 1930.
Location: Yanco Experiment Farm.
Introduction of foreign varieties, testing, strain
selection and purification of adapted commercial
types. No controlled pollination used, but
natural hybrids utilized when of value.
Location: Bathurst Experiment Farm.
372 YEARBOOK, 1937
Table 7. — Vegetable breeding and improvement work in foreign countries — Continue?!
Country, institution, and
official
Australia, Department of
Agriculture of New South
Wales, Sydney; H. Wen-
holz, director of plant
breeding.
Crop
Celery.
Cucumber. .
Lettuce
Muskmelon
Onion
Pea—
Peanut
Rhubarb-
Nature of studies
Squash and pumpkin.
Sweet corn.
Sweetpotato..
Introduction of foreign varieties, testing against
local varieties. Utah, Fordhook, and Pascal
(commercial United States) and inbreds of
Golden Phenomenal^ Golden Self Blanching, and
Golden Plume (California Agricultural Experi-
ment Station) were most promising.
Varietal crossing and selection for improvement of
uniformity and adaptability of commercial
slicing and of "apple" types; inbreeding for
mildew resistance; attempts to cross Cucumis
sativus (susceptible) with C. anguria and C. me-
tuliferus (resistant) failed.
New variety produced: Richmond Green Apple
by crossing commercial X Apple.
Location: Hawkesbury Agricultural College.
Introduction and adaptation studies of foreign
varieties, followed by selection and breeding.
Best introductions for winter crop, Imperial F and
Imperial 615 (U. S. D. A.); for summer. Iceberg
(United States), and Imperial P. Local variety
Yarrimundi is a pure green selected from an
Iceberg stock; some resistance to "slimy heart."
Location: Hawkesbury Agricultural College.
Introduction and adaptation studies of foreign
varieties (United States best source of material;
Spanish Gold, a Honey Dew type from France, is
promising). Varietal crossing and selection for
resistance to powdery mildew, using the Cali-
fornia-U. S. D. A. mildew-resistant strains with
susceptible sorts of high quality; also seeking
downy mildew resistance.
Location: Yanco Experiment Farm.
Objects: To obtain earlier, better storing, more
attractive adapted strains free from bolting and
thick necks; also resistance to thrips and disease.
Dominant varieties grown: Hunter River Brown
and Maitland White.
Location: Bathurst Experiment Farm and Hawkes-
bury Agricultural College.
Varietal hybridization and selection for good agro-
nomic characters plus resistance to Fusarium
martii and Mycosphaerella pinodes.
Most promising hybrid is Yorkshire Hero X Green-
feast.
Location : Hawkesbury Agricultural College; Bath-
urst and Yanco Experiment Farms.
Testing and selection from large number of intro-
ductions, varieties, and strains for large-seeded
Valencia or Virginia type with light-pink seed
coat.
Important Javanese introductions of Spanish type
are Toeban and Tannah.
Location: Grafton Experiment Farm.
Study of introductions and selection of seedlings of
introductions and local varieties.
South Australian Solid Red, a local variety of
excellent color, is most valuable producer of
promising seedlings.
Location: Hawkesbury Agricultural College and
Grafton Experiment Farm.
Introduction, selection, and hybridization to ob-
tain well-adapted high-quality varieties of uni-
form size and shape.
Varieties released: Ideal, Satisfaction, and two in-
troductions from the United States, Kitchenette
Hubbard (Minnesota Agricultural Experiment
Station) and Table Queen.
Location: Grafton Experiment Farm.
Hybridization and selection to obtain high-yielding,
vigorous-growing, high-quality sweet corn
adapted to local conditions.
New variety produced : Hawkesbury Sugar, from
crossing dent and sweet types.
Location: Hawkesbury Agricultural College.
Production of seedlings from which desirable selec-
tions may be made. Seeds obtained from more
tropical countries. Extensive introduction of
foreign varieties.
VEGETABLES—APPENDIX
373
Table 7. — Vegetable breeding and improvement work in foreign countries — Continued
Country, institution, and
official
Nature of studies
Australia, Department of
Agriculture of New South
Wales, Sydney; H. Wen-
holz, director of plant
breeding.
Sweetpotato .
Tomato.
Brazil, Institute Agronomico
do Estado de Sao Paulo,
Campinas; C. A. Krug,
head of genetics depart-
ment.
Costa Rica, Department of
Agriculture, Puntarenas;
Alan Kelso, chief of propa-
gation service.
Czechoslovakia, State Insti-
tute for Horticultural Re-
search, Pruhonice; Ing. Fr.
Landovsky, chief of divi-
sion for vegetable and seed
production.
Plant Breeding Institute of
Fiirst Lichtenstein, Led-
nice; Fr. Frirnmel, director.
Watermelon
Beans
Tomato
Cabbage .
Cucumber, onion
Tomato—
Radish..
Cucumber
Tomato
Best varieties: (Local) White Maltese, Wannop
and Ashburn (introduced from the Union of
Soviet Socialist Republics) N. 85.
Location: Hawkesbury Agricultural College and
Grafton Experiment Farm.
Introduction of foreign varieties and testing, varie-
tal and species crosses and selection for following
objects:
(1) Early varieties for staking.
Best introductions: Australian Earliana (a
farmer's selection), Break o' Day (U. S. D. A.),
and Potentate (from England).
(2) Resistance to fusarium wilt, spotted wilt,
and leaf mold or Cladosporium fulvum. Numer-
ous crosses of Red Currant with commercial
varieties.
Some promising hybrids obtained, showing re-
sistance to fusarium wilt: Australian Earliana X
Break o' Day and Earliana X Red Currant.
Latter resistant to spotted wilt. Leafmold-re-
sistant strains by L. J. Alexander of Ohio being
used in crosses.
(3) Main-crop pulping varieties.
Most promising hybrid: Red Pepper X Earli-
ana. Varieties in current use: Norana (from
north coast); Newport 4 and Master Marglobe
(from United States).
(4) Forcing varieties.
Best current varieties: Planter's Favorite (a
farmer's selection) and Potentate (from England).
Location: Hawkesbury Agricultural College; Bath-
urst, Grafton, and Yanco Experiment Farms.
Selection for good market type and resistance to
fusarium wut and anthracnose.
New variety produced: Wilt Resistant Thur-
mond Grey, by selection from variety locally
called Dark Seeded Grey Monarch.
Location: Hawkesbury Agricultural College.
Pure-line selection to improve stocks of main com-
mercial varieties grown in Brazil. Varietal and
species crosses to be made in breeding for regional
adaptability and resistance to mosaic, anthrac-
nose, and mildew (new work).
Introduced foreign varieties and local sorts studied
for disease resistance and other valuable char-
acters. Hybridization and selection will follow
(new work).
Selection of several wild native or naturalized
vegetable plants for adapting them to economic
use; tomato and a number of leaf vegetables are
included.
Hybridization and selection for increased earliness,
yield, quality, and improved local or special
adaptations.
Hybridization and selection for hardiness to per-
mit overwintering in the open field. Promising
selection from hybrid F3 of Groots X KSrnten.
Selection for stock improvement in local varieties.
New variety produced: Pruhonice, by crossing
Lucullus X Tuckswood. Early, resistant to
cracking, productive, high quality; for field or
forcing.
New variety produced: Pruhonice, by crossing
Triumph X Red Globe. Early (18 to 21 days)
high quality, attractive; for field or frame forcing.
Studies of hybrid vigor or heterosis are in progress,
and hybrid seed or "heterosis seed" of tomato
and spinach are produced on a large scale.
Special interest in cucumber breeding. New
variety produced: Zraojemska Nakladacka, a
variety for the conserving industry.
Hybridization and selection with special reference
to requirements of local growers and canners.
New varieties produced: (1) Blondkopfchen, by
crossing Yellow Cherry X Prinz Borghese.
Grown for canning. More productive than
Yellow Cherry. (2) Two other varieties, not
named, by crossing Lucullus X Prinz Borghese
and Coopers X Ficarazzi, respectively. For
canning and market.
374 YEARBOOK, 1937
Table 7. — Vegetable breeding and improvement work in foreign countries — Continued
Country, institution, and
official
Crop
Nature of studies
Plant Breeding Institute of
Fiirst Liechtenstein, Led-
nice; Fr. Frimmel, director.
Denmark (Reported by
Niels Esbjerg, State Ex-
periment Station, Blang-
sted) :
Other vegetables. __
England:
Horticultural Research
Station of Cambridge
University, Cam-
bridge; D. Boyes, di-
rector.
The Experimental and
Research Station,
Cheshunt; W. F. Bow-
ler, director.
The Sealy-Hayne Agri-
cultural College, New-
ton Abbot, Devon;
F. R. Home, professor
of botany.
Broccoli
Brussels sprouts
Cauliflower.
Onion
Parsnip
Pea
Cucumber
Lettuce...
Tomato...
Winter cauliflower or
broccoli.
Beans for canning, red peppers, and melons ar
receiving attention. A number of commercial
firms take special pride in their stocks of cucum-
bers, onions, kohlrabi, and celeriac or turnip-
rooted celery.
Research stations in Denmark are chiefly engaged
i n variety, strain and stock-testing, or seed-control
work. Vegetable improvement work is being
done by commercial agencies, the resulting strains
being submitted to Government agencies for
recognition before going into trade channels.
State Experiment Station at Blangsted produced
improved celeriac and is selecting cauliflower for
cold resistance.
Selection and progeny testing is principal
method used, with minor attention to hybridiza-
tion. Increasing work in disease-resistant selec-
tions largely on account of export trade to United
States. Some Danish firms reporting improve-
ment work:
A. Hansens, Kastrup — Cabbage, cauliflower,
spinach, radish, and carrot.
Chr. Olsen, Odense— Cabbage, cauliflower,
kale, brussels sprouts, radish, carrot, lettuce,
celeriac, spinach.
J. C. Helm-Petersen & Co., Aarhus — Cabbage,
carrot, beet, spinach, turnip-rooted parsley.
J. E. Ohlsens Enke, Copenhagen— Cabbage,
brussels sprouts, kale, celery, radish, greenhouse
lettuce, spinach, tomato, peas, snap beans.
Hybridization work with tomato; search for
"velvet spot" resistance. Hybridization with
peas and beans.
Hjalmar Hartmann & Co., Copenhagen —
Cabbage and cauliflower.
Union of Danish Cooperative Societies, Taas-
trup--Pure-line selection of beans and peas.
Hybridization and progeny testing of cabb ge,
beet, and pickling cucumber. Progeny testing
of onion, turnip-rooted parsley, radish, lettuce,
spinach, and tomato.
Production of Roscoff types of good curd texture,
disease resistance, and adaptability to specific
localities in England having different weather
conditions.
Object of work, to obtain varieties with small
sprouts for canning or special markets, and vari-
eties adapted to special conditions such as fen
soils.
Early, winter-hardy varieties are sought.
Production of English types for spring sowing and
Spanish types adapted to England.
Production of half-long, smooth, white varieties
for commercial use.
Production of new sorts for canning, hardy types
for fall planting, and multipodded types.
Improved varieties produced have been pri-
vately distributed to supporters of the work (sub-
scribers) and are not on the market.
This station deals only with greenhouse crops.
Breeding for a short-necked disease-resistant
variety.
Breeding for short-day types for winter culture.
Breeding for high yield, quality, and resistance to
Cladosporiumfulvum.
Productions are distributed first to subscribers
who support the research, later to general public.
Tomato E. S. 1 and Cheshunt Early Giant
lettuce are in general cultivation.
Intervarietal and intertype hybridization to obtain
succession of maturity, sorts both earlier and later
than those available. Roscoff, Cornish, Angers,
and Italian strains being used in breeding,
although only first 2 are at present adapted to the
environment. Some promising hybrid progenies.
VEGETABLES— APPENDIX 375
Table 7. — Vegetable breeding and improvement work in foreign countries — Continued
Country, institution, and
official
Crop
Nature of studies
Scotland, The Scottish Soci-
ety for Research in Plant
Breeding, Carstophine,
Edinburgh; William
Eobb, director.
Germany:
Versuchs- und Forsch-
ungsanstalt fur Wein-,
Obst-und Gartenbau,
Geisenheim; Professor
Dr. JRudolff, director.
Institut f iir Pflanzenbau
und Pflanzensuchtung
der Universitat, Halle;
Professor Dr. Roemer,
director.
Kaiser Wilhelm Institut
fur Zuchtungsfors-
chung, Muncheberg;
Professor Dr. Rudorf,
director.
Gartaerlehranstatt der
Landesbauerushaft
Kurinark, Oranien-
burg-Luisenbof; Dr.
Bonhert, agricultural
adviser.
Staatliclie Versuchs- und
Forschungsanstalt fiir
Gartenbau, Pillnitz;
Professor Schindler,
director.
Staatliche Lehr- und
Forschungsanstalt fiir
Gartenbau, Weihen-
stephan; Professor
Bickel, director.
Japan, Imperial Horticultural
Experiment Station, Okit-
su; T. Tanikawa, acting
director.
Tomato
Brassica spp
Beans, snap.
Peas
Rhubarb
Tomato
Kohlrabi.
Tomato...
Asparagus..
Caraway-
Dill
Mustard.
Brussels sprouts-
Cabbage
Kohlrabi.
Lettuce.
Totuato (forcing).
Asparagus..
Brassica sp..
Eggplant-
Pea.
Tomato..
Breeding and improvement work in progress upon
swedes or rutabagas.
Breeding and improvement work in progress.
Intertype and interspecific crosses studied with
reference to fertility relationships and inheritance
of specific characters with a view to possible value
in future breeding work.
Breeding for resistance to Colktotrichum in beans for
canning.
Breeding work in progress for increased yield and
earliness of sweet varieties.
Breeding work in progress for improved red color of
petrioles, lower acid content, more upright
growth, earliness, and disease resistance.
Workin charge ofDr. Sengbusch. Inter varietal and
interspecies crosses and selection (Lycoper&icon
esculeitfum and X. pimpineUifoimm) to obtain
improved earliness, freedom from fruit cracking
and leaf rolling, superior eating and keeping
qualities, resistance to cold and Cladosporium.
Promising hybrids have been obtained and are
being studied further.
Breeding for late frost resistance, high quality,
small leaves, earliness, is being started.
Promising results are being obtained in breeding for
increased earliness, resistance to fruit cracking,
and Phytophthora.
Crossing of selected parent plants followed by
selection for earlier, stronger-growing, rust-
resistant, tender varieties of good flavor.
Selection for improved seed setting, uniformity,
earliness, bright seed color, high oil content.
Selection for higher quality, improved seed setting,
uniformity of ripening.
Selection for large seed, high oil content, earliness,
and uniformity of ripening.
Improvement in winter hardiness, earliness, and
uniformity of growth and bud formation.
Improvement in growth and head formation,
storage qualities, solidity, and head leaf color.
Breeding whiter forcing varieties with more tender
flesh, improved form, upright uniform leaves,
earliness, resistance to cold.
Breeding for two different types: (1) Very quick-
growing sort for forcing in hotbeds; and (2) a
larger, slower-growing sort for coldframes and
open ground.
Breeding for rounder, brighter colored fruit, higher
yield, and resistance to Cladosporium. Resistance
of practical value has been obtained, but improve-
ment of fruit characters of such sorts must be
continued.
Testing and selection of promising varieties and
strains. Data for 1927 to 1936.
Fundamental research in genetics with special
reference to sterilities, compatibilities, effects
of inbreeding, and studies of hybrid vigor (1924-
32).
Hybridization and selection for resistance to "blue
rot", improved yield, uniformity, and quality.
Several promising strains obtained (1925 to date) .
New work started in breeding canning varieties
adapted to Japan, by hybridization and selection.
Also fundamental research in genetics (1935).
New work started for production of new varieties
for Japan, for market purposes.
376 YEARBOOK, 1937
Table 7. — Vegetable breeding and improvement work in foreign countries — Continued
Country, institution, and
official
Crop
Nature of studies
Mexico, Instituto Biotecni-
co. Work at numerous
locations. Reported by
G. Gandara.
Norway, Government Ex-
periment Station in Vege-
table Culture, Kvrthamar,
St. Jordal; A. H. Bremer,
director. (This station
succeeded the former insti-
tution known as The Gar-
den Cultivation Friends
Experiment Station in
1919.)
(Historical notes on Norwe-
gian vegetable varieties
based on information fur-
nished by Prof. Olav.
Moen, of the Agricultural
High School, Aas.)
Bean
Cucurbita sp
Tomato
Other vegetables
Bean, pole
Cucumber.
Lettuce
Muskmelon
Pea
Obtained a thick-rooted hybrid variety, Campo-
tillo, from Spanish variety of Phaseolus vulffaris
crossed with Mexican variety of P. coccineus.
Acclimatization studies of different varieties.
Studies of factors responsible for association of red
and yellow color with certain quality character-
istics as sweetness or acidity.
Acclimatization and disease resistance studies being
made on numerous local and introduced varieties
of broadbean, chickpea, peanut, muskmelon, and
watermelon.
Pure-line selection for early, productive green and
wax pole types that can be profitably grown in
Norway. Erstling only successful variety at
present, yields 30 percent more than any dwarf
type tested. Expect to release 1 or more new
varieties in 1937.
Hybridization and selection for very early varieties
of acceptable form and quality adapted to Nor-
way. Commonly grown early variety, Muromsk,
has low quality and good yield. Is being crossed
with high-quality Russiskdrue and Reinische
Vargebirgo.
Hybridization of varieties of differing responses to
day length to obtain varieties adapted to short,
long, and rapidly changing day lengths.
Cannot be grown in the open. Hybridization and
selection for varieties adapted to forcing under
Norwegian conditions.
Pure-line selection started by K. Weydahl in 1915
led to introduction of stocks of 6 well-adapted
strains in 1922, namely, Engelsk Sabcl, Witham
Wonder, Ne Plus Ultra Marrow, Saxa, Burton
Snabel, and Early June.
Hybridization and selection for better adapted
types, accompanied by genetic studies; linkage
shown between tall plant and parchment in pod
with 4 to 5 percent crossing over. Two dwarf
large-pod, parchment-free sorts introduced in
1829— Karl Weydahl and Bremers Marrow
Sugar.
Bremers Early Sugar selected from Sabel X
Saxa released in 1931. Numerous hybrids at
hand and genetic studies in progress.
Norwegian varietal improvement offers particular
difficulties because of the far northern location
and the sharp climatic contrasts existing within
short distances, as coast and valley versus moun-
tains; and windward versus leeward sides of the
mountains.
Skard selected an earlier bean than Erstling from
Reistad. Grau obtained Olsak by varietal hy-
bridization, also wax beans named Oslo Taroand
Smarbukk. Bergsgubber is a Norwegian selec-
tion from Nordstjernen.
Norwegian stocks of Amager are distinct and the
results of numerous growers' selections for adap-
tation to specific conditions. Various strains as
Berby, Amot, Tales Blatopp, Sandveds, Toten,
and others. Moens Kvitkalresultofmanyyears'
selection. Bossebo, Jatun, Stavanger Torv,
and Jatunsalgets Vinterkal are results of varietal
crossing.
Chr. Olsen started wrinkled-pea improvement by
selection in 1830, and many of present best varie-
ties believed result of his work, as Grimstead
Gartneris, Handes, and Bakkes.
Lund has developed an outdoor strain of Danish
Export and of Hannestad, and a forcing strain
of Eondine for Norway conditions.
VEGETABLES— APPENDIX 377
TABLE 7. — Vegetable breeding and improvement ivork in foreign countries — Continued
Country, institution, and
official
Crop
Nature of studies
Sweden:
Agricultural Experiment
Station, Alnarp; Carl
O. Dahl.
Bean
Brussels sprouts.
Cabbage
Pea-
Horticultural Institute
of W. Weibull & Co.,
Weibullsholms, Lands-
krona; H. Lamprecbt,
head of technical staff.
Bean, snap..
Carrot
Cauliflower.
Cucumber.
Pea
Spinach.
L. Daehnfeldts and G.
Hylten-Cavallius,
seedsmen, Halsing-
borg; Ernst Nilsson,
in charge.
Bean, field..
Bean, wax—
Pea
Hybridization and selection for improved yield
earliness, quality, and adaptabity to Sweden;
strains 3 to 5 days earlier than any known sort
obtained, also high-yielding wax sorts. All
require further selection before introduction.
Hybridization and selection for high yield and
cold resistance; work in progress.
Common X savoy cabbage crosses made for milder
flavor, good storage quality, and high yield.
Alnarp cabbage No. 1 and Alnarp cabbage
No. 2 released to the trade.
Hybridization and selection for high-quality, high-
yielding, large-podded, sweet, wilt-resistant peas
for home, market, and canning. Many promis-
ing lines obtained. Alnarp Sten's No. 1 and
Alnarp Sten's No. 2, released to the trade in
1927. They are high yielding and wilt resistant.
Alnarp Sabel is a selection from Sabel. Numer-
ous strains will soon be ready for release.
Selection and hybridization to obtain high-quality,
early, ^productive varieties adapted to Swedish
conditions of culture and use.
Stella, selected from strain grown on an old farm
in Sweden, introduced to the trade about 1925.
Early, thin hull, high yield. Alabaster II ob-
tained through pedigree selection from Swedish
variety Upplands; resistant to pod spot.
Express, a wax variety introduced in 1932, was
obtained by crossing German variety Daddel
with an unknown. Very early and high yielding.
Hegulas, a superior storage carrot, of qualities
otherwise similar to Chanienay.
Giant Swedish No. 147. Obtained from cross of
Giant Danish and an unnamed variety. Some-
what drought-resistant.
Perseus, developed from Rockford. Earlier and
more productive.
Nanna, a sugar type, obtained from cross of Furst
Bismarck X a red-flowering sort similar to Gray
Giant. High yield, quality, and good adapt-
ability. Extra Rapid, selected from Rapid,
which is uneven in earliness. Said to be earliest
pea grown. Released In 1927. Sylva, a marrow
pea, was selected from Fairbeards Nonpareil,
beginning in 1918. Released in 1925. Luna, an
edible podded sort, from cross of Roi des Gour-
mands and Witham Wonder.
Valkyria II was selected from Valkyria and intro-
duced in 1925. The plants are monoecious, high-
yielding, resistant to Peronospora. Color some-
what light. Herta is dark green, dominantly
but not completely monoecious, quick growing.
Derived from cross of Valkyria and Victoria.
Varietal crossing and selection to develop high-
yielding, high-quality strains and varieties
adapted to conditions in Sweden. Varieties
introduced to the trade as indicated.
Risbrinken, selected from unnamed variety.
Early and resistant to pod spot. Dwarf Brown,
introduced in 1933, from cross between Nord-
stern and a brown variety in 1919. Said to be
very hardy and adapted to northern Sweden.
A pedigree selection of Beurre Nain Sans Rivale
adapted to Swedish conditions.
Sugar types as follows: Norrlands, from Pilot X
Bismarck; Early Giant, from Sabel X Laxton;
Elitsabel, from Sabel X King; Giant Sabel,
selected from English Sabel; Giant Sabel Elit,
from Stens X English Sabel; Kings, a selected
strain of Roi des Gourmands; Improved King,
from Giant Sabel X King. Numerous strains of
marrow and sugar peas are in process of develop-
ment, principally by varietal crossing and
selection.
138904"— 37 25 ++
378 YEARBOOK, 1937
Table 7. — Vegetable breeding and improvement work in foreign countries — Continued
Country, institution, and
official
Union of South Africa, Divi-
sion of Plant Industry,
Nelspmit, East Transvaal.
Union of Soviet Socialist
Republics.
Crop
Nature of studies
Breeding for resistance to blight and bacterial wilt.
Breeding for resistance to wilt.
Unfortunately, up-to-date information from plant
breeders in the Union of Soviet Socialist Repub-
lics could not be obtained in time for including
in this report, but it should be pointed out that
they are among the most active workers in the
field today. Special emphasis has been placed
on thorough exploration of all promising parts of
the world for obtaining varieties and breeding
material of value. Very extensive programs are
in progress at numerous locations for studying
introduced materials in detail and for large-scale
hybridization and selection work. Large re-
sources and great energy are being devoted to
this work. There is no doubt that results of
considerable practical and scientific importance
are being obtained.
IMPROVEMENT OF
SWEET CORN
C. F. POOLE, Cytologist, Division
of Fruit and Vegetable Crops and
Diseases, Bureau of Plant Industry
X HE only genetic difference between the composition of a sweet
corn kernel and that of field corn is due to a single recessive gene out
of the hundreds or thousands of genes in corn. This gene makes the
sugary condition of the kernel persist in sweet corn; or, in other words,
prevents the conversion of some of the sugar into starch.
The first recorded observation of sweet corn by white men appeared
in 1779, when Lt. Richard Bagnall, of Sullivan's Indian Expedition,
returned from an Indian campaign to the west of the Susquehanna
with several sugary kerneled ears procured from the natives. We
know today that the Iroquois Indians cultivated at least two sweet
varieties, one white and one black — similar to Black Mexican — and
that the Indians of the upper Missouri included four sweet corns
among the 104 corn varieties they cultivated U-5).1
In 1828 Thorburn's seed catalog listed a single sweet corn variety,
and by 1881 the number of advertised varieties in all seed catalogs had
increased to 16. Today, by reason of an increased interest in the pro-
duction of hybrid sweet corn, it would be difficult to estimate with any
accuracy the number of sweet corn varieties and stocks on sale, but
it must run into many hundreds.
Considering its popularity, it may be surprising to some that the
region of sweet corn cultivation is confined practically to southern
Canada and the northern half of the United States. There are three
reasons for this restricted distribution. (1) The period during which
sweet corn kernels remain sweet after picking is of very short duration,
and at the higher temperatures farther south the sugars are rapidly
converted to starch. (2) The corn earworm, Heliothis obsoleta Fabr.,
is less injurious or is absent only in latitudes with winter tempera-
tures low enough to prevent winter pupation of the larvae. Earworm
injury in the Southern States is so great that the main dependence for
roasting ears is the naturally more resistant field corn, including such
varieties as Trucker's Favorite, Mexican June, and Tuxpan. These
varieties, together with practically all the field corns of the South, have
become relatively resistant to the corn earworm through natural se-
lection extending over a long period. This fact is being used to good
advantage {88) in converting some of the leading southern dents into
highly resistant sweet corns by appropriate crosses. The third reason
is much like the second, but in this case the condition is bacterial wilt
instead of an insect. This disease is especially severe in the South,
' Italic numbers in parentheses refer to Literature Cited, p. 392.
379
380 YEARBOOK, 1937
and sweet corn varieties are much more susceptible in general than the
southern field corns.
Prior to 1900, when the rediscovery by three European botanists
of Mendel's paper on hybridization in garden peas aroused greater
plant breeding activity than had hitherto been known, the literature
of sweet corn breeding was confined to descriptions of variety tests.
An examination of the experiment station bulletins around 1889,
especially in Illinois, Indiana, and Nebraska, shows the names of some
75 sweet corn varieties classified according to earliness or lateness of
maturity, color of kernels, and suitability for cultivation in those
States. Some attempts were then made to standardize names and
show which were synonymous. Early station bulletins from North
Carolina and Louisiana mentioned that field corns were productive
under local conditions, but sweet corn could not be successfully culti-
vated because of the damage inflicted by the corn earworm.
With few exceptions the men then practicing plant breeding failed
to conceive of the possibility of hybridizing different stocks of corn
with a view to producing new types for special purposes. Mendel's
paper, however, by clearly stating certain definite laws of inheritance
operating when character contrasts are introduced in a cross, showed
that breeding for special purposes could be done systematically and
with comparative ease. After 1900 the character of experiment sta-
tion publications changed from lists of varieties to reports of crosses
made with definite objectives, such as production of extra early ma-
turing stocks, and of better canning varieties with deeper and more
tender kernels, increasing the uniformity of all characteristics in can-
ning varieties, and increasing yield and resistance to disease or insect
attack.
WE CAN hardly overstress the importance to the canned-corn
industry of the all-embracing uniformity of characters resulting
from the production of crosses and top crosses of inbred lines of
sweet corn. The uniformity in texture and consistency of grains
and in shape and size of ears has practically revolutionized the
machinery and methods of handling in the cannery; and further-
more, in the field the even placing of the ears on the stalks and the
uniformity with which an entire field reaches maturity have brought
economies never before possible. These advantages are also evident
in more recent cannery practices, such as putting up corn in frozen
packs, and an increase in the whole-grain method of removing kernels
from the cobs. It is estimated that about 80 percent of the yellow
sweet corn grown for canning in 1937 will be from hybrid seed,
and half of this, or 40 percent of all yellow cannery sweet corn, will
be Golden Cross Bantam.
SWEET CORN 381
Among the first sweet corn breeders to work for specific ends without
knowledge of Mendel's laws was a Maryland physician, Stabler (44)-
In 1879 he planted alternate rows of Burr Mammoth and Stowell
Evergreen and removed the tassels from the latter, thereby obtaining
hybrid seed from which he selected an improved canning variety
called Roslyn Hybrid Sweet. The new variety had large ears, straight
rows, deep kernels, small cobs, and a higher yield than either parent.
Stabler later produced an earlier makiring evergreen variety, called
Early Stabler, by selecting seed from the first ears to set. He recog-
nized that even though the ears were open pollinated, so that the
pollen parent was unknown, it had to be early maturing to pollinate
an early silking plant, and consequently the ensuing selections would
be earlier than the original stock.
The interest aroused in genetics and plant breeding after 1900 was
promptly applied to sweet corn, first by Halsted, Kelsey, and their
colleagues in New Jersey, and later by East in Connecticut, Pearl,
Surface, and Sax in Maine, and Huelsen and Gillis in Illinois. These
workers established inbred lines through artificial self-pollination to
produce true breeding stocks and to eliminate defective characters.
With improved inbred lines they expected to analyze the factors of
inheritance and produce newly constructed varieties from specifica-
tions found in both parent stocks. At about the time of the Maine
work, Collins and Kempton (7), of the United States Department of
Agriculture, made the first deliberate attempt to breed a sweet corn
resistant to the corn earworm by crossing resistant dent varieties
with susceptible sweet corn varieties.
SWEET CORN BREEDING
Sweet corn is chiefly used as a canning vegetable almost throughout
the world and as a green garden vegetable in regions favoring its cul-
tivation. The activities of sweet corn breeders are predetermined by
these uses somewhat along the following lines:
1. For the canning industry, the production of high-yielding uniform
hybrid stocks with good quality, by crossing inbred lines among
themselves or top crossing inbred lines as pollen parents on commercial
varieties as seed parents. Both practices insure greater uniformity
in time of maturity, as well as in other characters, and increased yield.
2. Extension of the geographic range of the crop farther southward
through the development of improved earworm-resistant varieties of
sweet types by hybridization of susceptible varieties of good quality
with naturally resistant field corns; and the extension of the range
northward by selecting extra early maturing stocks.
Shortly before the timely rediscovery of Mendel's paper, Halsted
and his coworkers (IS, 14, 15, 16, 17, 18, 19, 20, 21) of New Jersey in
1898 began breeding sweet corn with the object of combining in one
variety the best features of Black Mexican and Egyptian (Washington
Market), which had white kernels. They observed that crossed
seed in this case could easily be identified on ears of Egyptian plants,
since corn has the advantage of exhibiting xenia.2 For example,
black aleurone color is dominant to clear in this cross, and any kernels
on a plant with white ears that chance to be pollinated by pollen grains
2 See the article on Fundamentals of Heredity lor Breeders, in this Yearbook.
382 YEARBOOK, 1937
from a black parent will develop into black instead of white kernels.
Black Mexican and white Egyptian occupied adjoining rows and the
breeders commenced their work merely by choosing black seeds from
Egyptian ears. Faster progress was made by raising a winter genera-
tion in the greenhouse, and in their earlier work Halsted and Kelsey
selected breeding stock from open pollinated ears. It was not until
1900 that they practiced artificial pollination and not until 1905 that
their reports began to include Mendelian terms. Notwithstanding
their primitive methods at the beginning, the new variety Voorhees
Red Sweet was fairly well fixed when it was released to the public in
1903. The variety combined features from the two parents and in
addition exhibited red kernels, a character not expressed in either
parent.
Immediately upon adoption of controlled pollination and Mendelian
conceptions, Halsted began an extensive hybridization program with
sweet corns with the specific object of improving stocks for earliness,
higher percentages of two- and three-eared stalks, and recombination
of the best features of diverse parents. At first Black Mexican was
used as pollen parent with Malakov, an extra-early variety recently
introduced from Russia, and with Garwood, Country Gentleman,
Striped Evergreen, Banana, and Golden Bantam. Many other
varieties were included later, and Black Mexican was omitted when
pollination from bagged tassels made xenia no longer important as a
device in this work to identify a cross. The problem of adequately
testing the new stocks was overcome by enlisting the aid of cooper-
ating farmers. In 1906, seed of six new varieties was widely dis-
tributed for trial and the year following four more were added to the
number, two of which were given names abbreviated from the two
parents, Malamo (Malakov X Premo) and Malakosby (Malakov X
Crosby).
At this time Halsted began crossing sweet corns with Iowa Silver-
mine (white) and Pride of Nishna (yellow), dent corns, further to
increase the yield of seed and stover. From the former he derived
Silver Sweet by crossing with Stowell Evergreen and Jersey Sweet by
crossing with Country Gentleman.
The order of importance of the elements that contribute to quality
in sweet corn depends on whether we are considering market varieties
or canning varieties. The market gardener places sweetness first,
followed by tenderness of the pericarp, or outer covering of the kernel,
then consistency or texture of the kernel contents. But since the
canner may add extra sugar to the brine, his specifications for the
breeder (9) place tenderness of the pericarp first and sweetness last,
with consistency of kernel as the requirement second in importance.
Sweet Corn for the Cannery
The chief factors in the selection of varieties for use in the canning
industry are deep kernels, yellow or white, according to local prefer-
ences; uniformity in all characteristics of the plant and ear; satisfactory
yields; high quality; and, in regions afflicted with insects or disease,
resistance to or escapement from injury. Previous to 1924, the date
when practical interest was first aroused in the production of hybrid
stocks from crossing inbred sweet corn lines, canned sweet corn was
SWEET CORN
383
obtained almost entirely from the four major varieties described in
table 1.
Table 1. — Sweet corns used for canning
Variety
Year in-
troduced
Color
Maturity date
Height
Cut corn
at 20 days
1860
1860
1882
1900
White..__
Early
Feet
5-fi
7-8
7
5-6
Percent
37.2
...do
Intermediate
45.9
do.
46.1
27.4
The data shown as percentage of cut corn at 20 days after the
appearance of the silks, as given by Culpepper and Magoon (8), are
included in order to indicate the efficiency of a variety in producing
the deep kernels best suited for canning. This figure is computed
by dividing the weight of cut kernels by the total weight before
cutting.
A serious drawback of all commercial varieties for canning purposes,
however, is the great variability in characters, and especially in the
time when individual plants reach maturity. This means that at
any given time a large percentage of underripe and overripe ears
must be taken, along with those in prime condition. A breeding
practice that would increase the uniformity in reaching maturity,
shape of ears, or texture of grains, as well as giving increased yield
or greater depth of kernels, would be desirable. The increase in
uniformity alone would be a great boon to the canning industry
because this results in a relatively much larger pack from a given
yield in the field. It was shown by G. H.Shull in 1908 that increased
yield and a high degree of uniformity in all characteristics would
result from crosses between inbred lines. Many years before this,
about 1880, W. J. Beal, of the Michigan Agricultural College, observed
that hybrid vigor and somewhat greater uniformity resulted from
the crossing of commercial varieties in the field. At that time he
proposed planting alternate rows of two field varieties, detasseling
one and using ears from the detasselled variety to obtain hybrid seed.
More Recent Breeders
In the summer of 1907 Pearl and Surface (89) in Maine commenced
investigations on sweet corn for the specific purpose of producing seed
adapted to Maine rather than to Connecticut and Massachusetts —
the chief sources of seed. For the production of improved canning
varieties their immediate objectives were greater earliness, higher
yield, and improved ear shape. They produced inbred lines by in-
breeding for several generations and discarded the poorer fines while
retaining the better ones. Their contribution to sweet corn breeding
practice was the selection of breeding stock on the basis of the per-
formance of the progeny and not upon the appearance of the ear and
plant, which had. been the practice until that time. In their own
words, "the objects of selection must be to discover and separate
the desirable genotypes from the poor ones." After 3 years of such
work Maine farmers had better locally grown seed than could be
purchased elsewhere.
384
YEARBOOK, 193 7
Figure 1. — Method of producing double-cross hybrid seed corn and representative
ears of the crop produced from hybrid seed.
SWEET CORN 385
In Illinois, which, according to the latest statistics, is usually slightly
ahead of Iowa as the leading sweet corn State, both in acreage and
in total pack, breeding operations were begun about 1926 by Huelsen
and Gillis, as reported by Keilholz (82). Their methods were much
the same as those already in use elsewhere, but they emphasized the
improvement of quality by use of the puncture test to identify
the most tender lines for use in breeding. The test shows the
pressure in grams per square centimeter required to penetrate
the pericarp of the corn kernel. Huelsen and Gillis learned that
high degrees of tenderness are exhibited in dent corns as well as in
sweet corns.
In Connecticut the production on a commercial scale of cross-bred
seed from inbred lines in field corn was first practiced in 1921 by George
S. Carter, of Clinton (SO). Shortly thereafter, in 1924, the Connecti-
cut Agricultural Experiment Station introduced an Ft or first-genera-
tion hybrid sweet corn called Redgreen, produced from two inbred
lines, one being Stowell Evergreen and the other from a variety of
unknown parentage. This hybrid stock was soon grown and canned
by the W. N. Clark Canning Co., of Rochester, N. Y., and its superior
characters in adaptation to locality, productivity, uniformity of matur-
ing, and quality were immediately recognized.
Redgreen was not as successful elsewhere as in New England,
central New York, and certain sections of the Northwest. Today
practically every experiment station has several or many such cross-
bred stocks, many of which are sold by the leading vegetable seedsmen.
The lead in such activities was taken by the Connecticut station (80,
SI), the Minnesota station (28), and the Purdue University station
in cooperation with the United States Department of Agriculture.
Figures 1 and 2 illustrate the methods and results obtained in producing
single- and double-crossed corn.
The most popular and most widely adapted of these hybrid stocks
is Golden Cross Bantam, produced about 1927 by Smith (48), of the
Department, in cooperation with the Purdue University station by
crossing Purdue 39 (Purdue Bantam) and Purdue 51, both inbred
lines of Golden Bantam. Purdue 39 has attained some degree of
commercial importance in its own right by reason of its resistance to
bacterial wilt or Stewart's disease (Aplanobader stewarti (E. P.
Smith) McC), high quality, and yield.
The great popularity of Golden Cross Bantam is chiefly due to its
yield, canning qualities, uniformity, and resistance to bacterial wilt
(figs. 3 and 4). This disease is most serious in latitudes close to 40°
north and is of importance mainly in sweet corns, sometimes destroy-
ing almost the entire crop. The earlier maturing varieties are most
susceptible. A recent study of Stewart's disease (26) recognizes two
distinct genetic types of resistance: (a) Vigor-correlated, inferred
from the fact that vigorous hybrids between some low-resistant inbred
strains are more resistant than either parent; and (b) true resistance,
shown by the fact that hybrids from low-resistant inbreds are less
resistant than hybrids from high-resistant inbreds. Golden Cross
Bantam may owe its high degree of resistance to both these causes,
since it has hybrid vigor and one of its parents, Purdue 39, is also
highly resistant.
386
YEARBOOK, 1937
FIRST YEAR
DETASSELEO
DETASSELEO
(Bx A)x(CXD)
,y DOUBLE-CROSS SEEO
FOR COMMERCIAL PLANTING
SIN6LE-CR0SS PLANT ( B X A ) J 1^ SINGLE-CROSS PLANT ( C X D)
Figure 2. — Diagram of method of crossing inbred plants and the resulting
single crosses to produce double-cross hybrid seed.
The tremendous importance of these hybrid sweet corns, and
particularly Golden Cross Bantam, is indicated by the fact that it is
estimated that about 80 percent of the yellow sweet corn which will
SWEET CORN
387
be grown for canning in 1937 will be grown from hybrid seed. It is
estimated that half of this, or 40 percent of all yellow cannery sweet
corn, will be Golden Cross Bantam.
Figure 3. — Golden Cross Bantam, a variety resistant to bacterial wilt or Stewart's
disease. It remains healthy on wilt-infected soil and makes a normal crop.
Top-Crossed Sweet Corn
The use of inbred lines as pollen parents crossed on commercial
varieties as seed parents — called the top cross — for producing uni-
formly maturing and high yielding corn stocks was begun at the
Connecticut Agricultural Experiment Station in 1917 with field corn.
The practice was soon used on sweet corn with excellent results, and
.188
YEARBOOK, 1937
in 1935 the station recommended to the trade two early stocks,
Spancross C-2 and Marcross C-6, and two midseason stocks, Whip-
cross C-6.2 and Whipcross C-7.2. In addition to these they recom-
mended for the 1936 trade the following new top crosses: Marcross
C-13.2, Burcross C-2,
Sencross C-7, Dale-
cross C-2, Orcross C-2,
Coincross C-2, and
Stancross C-2. The
1935 seed catalog of
one of the vegetable
seedsmen listed four
top crosses, all of which
were produced by its
own breeding staff. In
recommending the top-
cross method, Jones
and Singleton (81)
say:
From the standpoint of
ease of producing seed and
the adaptability of this
seed, as compared to that
of single crosses (between
two inbred lines), there is
much to be said in favor of
variety-inbred crosses (top
crosses) .
The importance to
the canned-corn indus-
try of the all-embracing
uniformity of character
resulting from the pro-
duction of crosses and
top crosses of inbred
lines can hardly be
overstressed. The uni-
formity in texture and
consistency of grains
and in shape and size
of ears has practically
revolutionized the
machinery and meth-
ods of handling in the cannery; and furthermore, in the field the
even placing of the ears on the stalks and the uniformity with
which an entire field reaches maturity have brought economies
never before possible. These advantages are also evident in
more recent cannery practices, like putting up corn in frozen
packs and the whole-grain method of removing kernels from the
cobs. In each instance the uniform texture of grain in single-cross
and top-cross stocks of sweet corn makes them superior to the
open-pollinated corn varieties.
Figure 4. — Golden Bantam, a variety susceptible to
bacterial wilt, growing in infected soil near the plant
shown in figure 3. Golden Bantam was practically a
total loss in this test.
SWEET CORN 389
Market Sweet Corn Breeding
Many of the varieties bred for the canning industry also are suited
to market growing. In addition, there is need for extremely early
strains for the extreme northern areas of the territory. In the South
the question of earworm resistance is of major importance, and, if
resistant strains are developed, sweet corn culture may increase in
importance in this region.
About 1913 Collins and Kempton (7), of the Department, began a
study on earworm resistance in dent and sweet corn. They obtained
two highly resistant dent varieties, which were crossed with three
susceptible sweet varieties, Stowell Evergreen, Early Evergreen, and
Cory. The hybrid progenies proved more resistant than the com-
mercial varieties. Prolongation of the husks beyond the tip of the
ear and thickness of the husks were found to be associated to some
extent with low damage. The evidence indicated that increased
resistance of the hybrids also was due to other characters not measured
but probably correlated with husk prolongation. The presence of
some volatile substances distasteful alike to the moth and larva, but
too elusive for measurement, was suggested.
Mangelsdorf, of Texas, crossed the highly earworm-resistant dent
varieties, Mexican June and Surcropper, with the sweet variety
Country Gentleman, and continued backcrossing to the dent parent
for several generations. Eventually he obtained two varieties of
sweet corn, Honey June and Surcropper Sugar, which to outward
appearances were practically identical in plant characters with their
dent parents and were highly resistant to the earworm, but which in
addition were sweet. In numerous tests of the adaptation of these
two sweet corns to conditions in Texas (28, 24) and in California (40,
41, 42), the degree of earworm resistance has been demonstrated to be
superior to that shown in any other sweet corn varieties with the possible
exception of Papago, a commercially unpromising sweet corn produced
by Freeman (12) at the Arizona station, and of Aunt Mary's Sweet.
Papago was produced from a few sweet grains found in the summer
of 1910 on ears of squaw (flour) corn grown by the Papago Indians.
Aunt Mary's Sweet is a recently introduced sweet corn from Ohio,
which has been carefully nursed from year to year for perhaps a century
on a single farm near Darby Plains. Such antiquity suggests Indian
origin, and this is the expressed belief of the introducer, L. R. Bonne-
witz, of Van Wert, Ohio. The point of Indian origin might well be
stressed for Papago and Aunt Mary's Sweet, since it is to be expected
that the inherent earworm resistance of maize varieties in possession
of the Indians was due to a fixation by natural selection of resistance
to earworm attack.
Florida 191 and Suwanee Sugar, recently produced by the Florida
station, have given much promise as earworm resistant converted
dent-sweet corns when tried in the diverse environments of the South-
east and the far West. More recently, Georgia 439 and Georgia 428
from the Georgia Experiment Station have indicated promise equal
to that of the best strains of Honey June (23).
In the last 4 or 5 years a number of investigators in widely distant
States have independently conducted tests of rather extensive lists of
390 YEARBOOK, 1937
varieties of sweet corn to determine their earworm resistance and value
for market or breeding purposes. In tests at Davis, Calif. (Jfi, I/.1),
Winter Haven, Tex. (28, 24)t and Charleston, S. C, certain varieties
were consistently outstanding in earworm resistance, namely, Honey
June, Surcropper Sugar, Papago, Aunt Mary's Sweet, Florida 191,
and Oregon Evergreen. The relative resistance of these sorts varied
among the several tests, but they were of the same general degree of
resistance.
Even with the high degrees of resistance thus far uncovered, progress
in breeding earworm resistant sweet corns is still far from satisfactory.
Other hybrids have recently been made by Mangelsdorf in Texas
(see the table of introductions in the appendix) and by Poole in Cali-
fornia, using southern dent corns like Tuxpan and Davis Prolific that
are even more resistant than the first dent parents used in producing
Honey June and Surcropper.
Evidence obtained during 2 years of study by the California
station has demonstrated, in statistically significant tests, that high
earworm resistance is altogether independent of length or thickness
of husks.
Other possible factors not correlated with resistance are length of
ear, weight of ear, height of plant, and length of time required for
maturity (4®)- Promising lines of investigation as yet untried in-
clude the search for factors determining volatile compounds that
repel laying moths, suggested by Collins and Kempton, measurement
of the tightness of the husk covering, and determination of the quality
of husk covering. These lines of investigation will require collabora-
tion with specialists outside the field of genetics, or the development of
a special technique, before quantitative measurements can be taken.
Although it is still too early to estimate the extent to which these
new sweet corns will extend the geographic range of sweet corn cul-
tivation, there is no question regarding the interest of truck and home
gardeners in present efforts. Honey June in particular has aroused
enthusiasm among Texas and California growers, and one railroad
company in Texas has planted large acreages for shipment of green
sweet corn to northern points.
GENETICS 3
The genetics of sweet corn is the same as the genetics of corn in gen-
eral, except for the particular genes responsible for the sugary condi-
tion of the endosperm. Corn genetics has been so adequately treated
in the ] 936 Yearbook of Agriculture (27) that no further reference is
necessary except for considerations peculiar to sweet corn.
As has been said, the only genetic distinction to be drawn between
starchy endosperm and sweet endosperm is the fact that the normal
gene Sut (starchy) at locus 71 on chromosome IV (10) in field corn has
mutated to sut (sugary) in sweet corn. There is another allelomorph
of this gene at the same locus, and in addition two nonallelomorphic
sugary genes on two other chromosomes than number IV, which will
be discussed below. The sugary mutations result not only in a higher
total sugar content but also in a persistence of the sugary condition of
the endosperm to maturity. All other characteristics of the sweet
a This section is written primarily for students or others professionally interested in genetics or breeding.
SWEET CORN
391
com varieties, such as short stature, early maturity, loose husks, etc.,
are shared in common with field corn.
The investigator who seeks to effect certain combinations between
sugary or sweet corns and nonsugary corns may encounter aberrant
monohybrid ratios involving the sugary character. These aberrant
ratios are clue in some cases to the action of genes linked with sui, but
also may be due to other causes (2, 3, 4, 5, 6, 33, 34-, 35).
Mangelsdorf (37) investigated the respective rates of growth of
pollen tubes carrying 8ut and. sui and finds that Sui pollen tubes have
an accelerated growth rate at the start and that sut pollen tubes grow
as fast as Sih when the initial handicap is overcome.
In most other cases reported in the literature it appears that when
both Su and su appear together in one organism, the^ F2 segregates in
entirely normal monohybrid-ratios. The first exception was noted in
1920 by Harper (22), who reported that when two sugary races were
crossed the resultant Ft was starchy, indicating two nonallelomorphic
sugaries. Subsequent investigations have shown that there are indeed
two previously unknown nonallelomorphic sugary genes, su2 on
chromosome VI (11) and su3 on chromosome IX (Eyster, unpublished,
10). Furthermore, there is some evidence that at the swt locus on
chromosome IV there is a third member of the series, suf™, producing
a sugary kernel not as sweet as suu and which apparently is associated
with the presence of the gene du, dull endosperm, on chromosome X
(unpublished, communication from Mangelsdorf, also mentioned in 10) .
A condition called "pseudostarchy" has been analyzed by Jones (29)
and is thought to be caused by the complex interaction of three domi-
nant genes with the sut gene. One gene is necessary for the full
expression of pseudostarchy, a second inhibits the shrinkage of sugary
kernels, whereas the third dominant gene produces an opaque
appearance of the dried kernels.
In an investigation of the chemical composition of known endo-
sperm genotypes from crosses of dent X sugary, Lindstrom and Ger-
hardt (36) showed (table 2) an increase of sugars and a decrease of
starches for each additional su gene (expressed as s in table 2) obtained
in the recombinations resulting from reciprocal Fx matings and back-
crosses, or in an F2 generation.
Table 2.-
-Carbohydrate percentages for whole kernels {moisture-free basis)
for different types of crosses and known genotypes
Cross type '
Endosperm
genotype
Samples
Total
sugar
Dextrin
Starch
Carbo-
hydrate
index '
White dent
sss_ _
Number
3
3
4
1
4
3
3
2
4
3
Percent
2.3
4.9
2.7
3.6
1.8
5.3
2.2
4.5
2.3
6.3
Percent
1.9
24.5
2.1
1.7
1.6
26.7
2.2
25.9
2.7
29.1
Percent
56.6
27.9
53.6
56.1
57.5
23.1
55.8
27.1
57.5
21.6
0.07
1.05
Fi (HP X E)
SSs
.09
Fi (E X HF).
ssS— -
SSs
.09
Fi X E
.06
1.34
E X Fi -- -
ssS.
.08
1.12
F2 — -
SSS.. -
.09
1.59
' HF=Higb.Cat strain; E=evergreen parent. 2 Ratio of total sugar plus dextrin to starch.
392 YEARBOOK, 1937
In another analysis of chemical composition of known endosperm
genotypes involving the sugary gene, Abegg (1) demonstrated a
cumulative relationship for percentage of crude fat relative to the
genes sugary and waxy in the following series:
Percent of
Genotypes: crviefat
Su su su Wx wx wx 1.0
Su su su wx wx wx 1. 4
Percent of
Genotypes — Continued. cmdefat
su su su Wx wx wx 2. 6
su su su wx wx wx 3. 0
The typical ear of corn possesses rows of kernels in even numbers
because the female florets of the ear are arranged in pairs, each
member of which has two ovules. The rows are straight because
only one ovule on each floret develops, and the relatively uncrowded
ear displays its kernels in an evenly rowed condition. The sweet corn
variety Country Gentleman, however, is unique in the fact that the
second ovule of each floret also develops and produces a crowded
zigzag or "shoe-peg" condition. Huelsen and Gillis (25) investigated
the inheritance of the apparently unrowed condition in Country
Gentleman by carrying to the F3 generation a cross between Country
Gentleman and Narrow Grain Evergreen, the latter with typical
straight rows. Intermediate degrees of zigzagging were sometimes
difficult to classify, but on the whole the data conformed quite well
to the working hypothesis that the unrowed condition of Country
Gentleman was due to the operation of two pairs of recessive genes,
px px and fi p2, the chromosomal locations of which have not yet
been identified. According to hypothesis the history of this cross is
symbolically represented as Narrow Grain Evergreen, rowed
(P1P1P2P2) X Country Gentleman, unrowed (piPiPzPi-)
LITERATURE CITED
(1) Abegg, F. A.
1929. EFFECTS OF WAXY AND SUGARY GENES ON RESERVES WITH SPECIAL
REFERENCE TO MODIFICATION OF THE WAXY RATIO IN MAIZE.
Genetics 14: [270J-285, illus.
(2) Brink, R. A.
1925. MENDELIAN RATIOS AND THE GAMETOPHYTE GENERATION IN ANGIO-
sperms. Genetics 10: [359]-394, illus.
(3)
1927. the sugary gene as a modifier of the waxy ratio. Genetics
12: [461J-491.
(4) and Burnham, C. R.
1927. NUCLEUS AND CYTOPLASM IN RELATION TO DIFFERENTIAL POLLEN-
TUBE growth. Natl. Acad. Sci. Proe. 13: 238-242.
(5) and Burnham, C. R.
1927. DIFFERENTIAL ACTION OF THE SUGARY GENE IN MAIZE ON TWO
alternative classes of male gametophytes. Genetics 12:
[348]-378.
(6) and MacGillivray, J. H.
1924. SEGREGATION FOR THE WAXY CHARACTER IN MAIZE POLLEN AND
DIFFERENTIAL DEVELOPMENT OF THE MALE GAMETOPHYTE.
Amer. Jour. Bot. 11: 465-469.
(7) Collins, G. N., and Kempton, J. H.
1917. BREEDING SWEET CORN RESISTANT TO THE CORN EARWORM. Jour.
Agr. Research 11: 549-572.
(8) Culpepper, C. W., and Magoon, C. A.
1924. STUDIES UPON THE RELATIVE MERITS OF SWEET CORN VARIETIES FOR
CANNING PURPOSES AND THE RELATION OF MATURITY OF CORN
to the quality of the canned product. Jour. Agr. Research
28: 403-443, illus.
SWEET CORN 393
(9) Culpepper, C. W., and Magoon, C. A.
1927. A STUDY OP THE FACTORS DETERMINING QUALITY IN SWEET CORN.
Jour. Agr. Research 34: 413-433, illus.
(10) Emerson, R. A., Beadle, G. W., and Fraser, A. L.
1935. a summary of linkage studies in maize. N. Y. (Cornell) Agr.
Expt. Sta. Mem. 180, 83 pp.
(11) Eyster, W. H.
1934. genetics op zea mays. Bibliog. Genetica 11: [187]-392, illus.
(12) Freeman, G. F. '
1915. papago sweet corn, a new variety. Ariz. Agr. Expt. Sta. Bull.
75, pp. [4531-467, illus.
(13) Halsted, B. D.
1906. breeding sweet corn — co-operative tests. N. J. Agr. Expt.
(U) . Sta. Bull. 192, 30 pp., illus.
1907. station novelties in truck crops, further distribution of
q5n seed. N. J. Agr. Expt. Sta. Bull. 199: 1-14, illus.
1907. novelties in vegetable fruits. general TRIALS FOR 1908.
N. J. Agr. Expt. Sta. Bull. 209: 1-11, illus.
(16) and Kelsey, J. A.
1903. experiments in crossing sweet corn. N. J. State Agr. Expt. Sta.
Ann. Rept. (1902) 23: 380-383, illus.
(17) and Kelsey, J. A.
1904. experiments with sweet corn. N. J. State Agr. Expt. Sta. Ann.
Rept. (1903) 24: 463-471, illus.
(18) and Kelsey, J. A.
1904. experiments in crossing sweet corn, a new variety: the
voorhees red. N. J. State Agr. Expt. Sta. Bull. 170, 22 pp.,
illus.
(19) and Owen, E. J.
1907. experiments with sweet corn. N. J. State Agr. Expt. Sta.
Ann. Rept. (1906) 27: 376-392, illus.
(20) Owen, E. J., and Shaw, J. K.
1906. sweet corn upon the home grounds. JN. J. State Agr. Expt.
Sta. Ann. Rept. (1905) 26: 428-442, illus.
(21) — — — Owen, E. J., and Shore, N. D.
1908. experiments with sweet corn. N. J. State Agr. Expt. Sta.
Ann. Rept. (1907) 28: 265-288, illus.
(22) Harper, R. A.
1920. inheritance of sugar and starch characters in corn. Torrey
Bot. Club. Bull. 47: 137-186, illus.
(23) Hawthorn, L. R.
1936. further studies of earworm damage in sweet corn varieties
of texas. Amer. Soc. Hort. Sci. Proc. (1935) 33: 505-507.
(24) and Fletcher, R. K.
1934. earworm damage in sweet corn varieties. Amer. Soc. Hort.
Sci. Proc. (1933) 30: 550-553.
(25) Huelsen, W. A., and Gillis, M. C.
1929. inheritance of kernel arrangement in sweet corn. 111.
Agr. Expt. Sta. Bull. 320, pp. 301-336, illus.
(26) Ivanoff, S. S., and Riker, A. J.
1936. GENETIC TYPES OF RESISTANCE TO BACTERIAL WILT OF CORN.
(Abstract) Phytopathology 26: 95-96.
(27) Jenkins, M. T.
1936. corn improvement. U. S. Dept. Agr. Yearbook 1936: 455-522,
illus.
(28) Johnson, I. J.; Doxtator, C. W.; Hayes, H. K.; and Crim, R. F.
1936. Minnesota corn hybrids. Minn. Agr. Expt. Sta. Bull. 326,
23 pp., illus.
(29) Jones, D. F.
1919. selection of pseudo-starchy endosperm in maize. Genetics 4:
[364]-393, illus.
(30) and Singleton, W. R.
1934. crossed sweet corn. Conn. State Agr. Expt. Sta. Bull. 361,
pp. [489]-536, illus.
138904°— 37 26
394 YEARBOOK, 1937
(31) Jones, D. F. and Singleton, W. R.
1935. THE IMPROVEMENT OP NATURALLY CROSS-POLLINATED PLANTS BY
SELECTION IN SELF-FERTILIZED LINES. II. THE TESTING AND
utilization of inbred strains of corn. Conn. State Agr.
Expt. Sta. Bull. 376, pp. [653K691, illus.
(32) Keilholz, F. J., compiler and editor.
1927. sweet corn improvement shown in yield figures, sweet
corn again benefited by phosphorus, potash. hi. agr.
Expt. Sta. Ann. Rept. 40: 247-251, illus."
(33) Kempton, J. H.
1919. INHERITANCE OF WAXY ENDOSPERM IN MAIZE. U. S. Dept. Agr.
Bull. 754, 99 pp., illus.
(34)
1927. AGE OF POLLEN AND OTHER FACTORS AFFECTING MENDELIAN RATIOS
in maize. Jour. Agr. Research 35: 39-74, illus.
(35) Kiesselbach, T. A., and Petersen, N. F.
1926. THE SEGREGATION OF CARBOHYDRATES IN CROSSES BETWEEN WAXY
and starchy types of maize. Genetics 11: [407]-422, illus.
(36) Lindstrom, E. \V., and Gerhardt, F.
1927. inheritance of chemical characters in maize. Iowa State Col.
Jour. Sci. 2: 9-18.
(37) Mangelsdorf, P. C.
1929. THE RELATION BETWEEN LENGTH OF STYLES AND MENDELIAN
segregation in a maize cross. Amer. Nat. 63: 139-150.
(38)
1934. growing sweet corn in texas. Tex. Agr. Expt. Sta. Circ. 69,
27 pp., illus.
(39) Pearl, R., and Surface, F. M.
1910. experiments in breeding sweet corn. Maine Agr. Expt. Sta.
Bull. 183, pp. [249]-316, illus.
(40) Poole, C. F.
1935. CORN-EARWORM RESISTANCE IN MAIZE VARIETIES AT DAVIS, CALI-
FORNIA. Amer. Soo. Hort. Sci. Proc. (1934) 32: 453-457.
(41)
1936. ADAPTABILITY OF MAIZE VARIETIES IN CALIFORNIA. (Abstract)
Amer. Soc. Hort. Sci. Proc. (1935) 33: 495.
(42)
1936. new sweet corns resistant to earworm. Amer. Soc. Hort.
Sci. Proc. (1935) 33: 496-501.
(43) Smith, G. M.
1933. golden cross bantam sweet corn. IT. S. Dept. Agr. Circ. 268,
12 pp., illus.
(44) Stabler, A.
1904. sweet corn, breeding, growing, and curing for seed. Md.
Agr. Expt. Sta. Bull. 96: [31]-43.
(45) Tapley, W. T.; Enzie, W. D.; and Van Eseltine, G. P.
1934. sweet corn. In Vegetables of New York, v. 1, pt. 3, 111 pp.,
illus.
POPCORN BREEDING
ARTHUR M. BRUNSON, Agrono-
mist, Division of Cereal Crops and
Diseases, Bureau of Plant Industry
Jr OPCORN is a peculiarly American crop. Not only was it unknown
to white men before the discovery of North America, as was all maize,
but its cultivation and use for popping is almost entirely restricted to
the New World. European visitors frequently express surprise at
this unique form in which corn is available for human consumption.
It seems practically certain that popcorn was grown and popped
by the Indians before the coming of Columbus. The records, al-
though fragmentary, indicate that popped corn either whole or pul-
verized was used in native food dishes by various tribes in both North
America and South America. Popcorn kernels and specially shaped
earthenware dishes thought to be corn poppers have been discovered
among prehistoric Indian remains in South America. In early Span-
ish writings, reference is made to the rituals of the Aztecs in which
one hour before dawn there sallied forth all these maidens . . . crowned with
garlands of maize, toasted and popped, the grains of which resembled orange
blossoms, and on their necks thick festoons of the same which passed under the
left arm.
BASIS OF POPPING BEHAVIOR
The phenomenon of popping in corn is not limited to popcorn, but is
exhibited to the greatest degree in this subspecies (Zea mays var.
everta Bailey). Many flint corns under proper conditions will pop
passably well, and some of the horny dents will occasionally pop a
little. Even among the true popcorns there is a wide variation in
the degree of popping. The ability to pop seems to be conditioned
by the relative proportion of horny endosperm where the starch
grains are embedded in a tough, elastic colloidal material, which con-
fines and resists the steam pressure generated within the granule until
it reaches explosive force.1 Some varieties of sorghum with seed of a
dense flinty structure, such as Pink kafir, pop very well. Manufac-
turers of breakfast cereals have perfected mechanical methods of con-
fining steam pressure within grains until it is suddenly released, when
they puff or pop to several times their original volume.
DISTRIBUTION, VARIETIES, AND DESIRABLE QUALITIES
Compared with dent corn, popcorn is a relatively minor crop. Only
about 0.1 percent of the total corn acreage of the United States
ordinarily is occupied by popcorn. It is grown almost solely for
human consumption as freshly popped corn or as a basis of popcorn
i Weatherwax, P. the poppino or corn. Ind. Acad. Sci. Proe. 1921: 149-153. 1922.
395
396 YEARBOOK, 1937
confections. It has approximately the same chemical analysis and the
same feeding value as dent corn. Thus, popcorn may be substituted
for dent corn as feed for livestock if occasion demands, although the
lower acre yield and the hardness of the endosperm, which necessitates
grinding, make it uneconomical to do so under ordinary circumstances.
It is probable that popcorn is grown as a family garden crop for home
consumption in every State in the Union. A very considerable proportion
of the total popcorn production is represented by these small growers
whose crop is used in the home or is sold only locally. A multitude
of varieties, colors, and types of popcorn are used for this purpose.
Commercial production to supply vendors, manufacturers of pop-
corn confections, and the general retail grocery trade has been highly
specialized and localized until the last 2 or 3 years. Sac and Ida
Counties in western Iowa have been the principal center of commercial
popcorn production. Valley County in central Nebraska and four or
five counties in northeastern Kansas have also been important in
commercial production.
Very recently Iowa, Nebraska, and Kansas seem to have been
somewhat less important as centers of commercial production. This
has been due in part to a changing demand, which in recent years has
favored varieties too late to mature satisfactorily in northern regions,
but more largely to the unprecedented series of disastrous droughts
during the last few seasons that have centered around the traditional
commercial popcorn region. As a consequence of crop failures, pop-
corn prices have been abnormally high, and therefore scattered
growers in many localities outside the worst of the drought area have
found popcorn growing very profitable during the years when the
total production of the country was at a low ebb. Whether the present
distribution will continue during years of normal production is a ques-
tion for the future which only the complex interaction of economic
and agricultural factors can decide.
Although there are in existence innumerable types and varieties of
popcorn, only five or six are of commercial importance. Until com-
paratively recently, White Rice, Jap Hulless (Japanese Hulless), and
Queen Golden were the chief varieties used. The variety of popcorn
called South American, which was introduced some 15 years ago,
increased rapidly in favor in the popcorn trade and soon became a
serious competitor of the other varieties. The large size of the kernel,
its yellow color, and its peculiar "mushrooming" characteristic in
popping seemed to catch the public fancy enough so that its toughness
and mediocre quality were largely overlooked. An old variety re-
named Spanish popcorn was in vogue for a few years, because the
large size of its kernels and its ability to withstand processing fitted it
admirably for the manufacture of caramel confections. A small-
kerneled, smooth, yellow variety of high popping expansion, known
variously as Supergold, Sunburst, or Yellow Pearl, also has become
of commercial importance. The old Queen Golden corn has now been
almost entirely displaced by South American and Supergold, its
yellow competitors.
In popcorn the desirable characters to be achieved by the breeder
include all of the attributes of a good variety of dent corn, and in
addition must include high expansion and tenderness. Fortunately,
POPCORN 397
high popping expansion and tenderness of the popped kernels seem
to be closely correlated, so that in attaining high popability one also
is very likely to have a tender product. The absence of a coarse
hull and the presence of a good flavor are also desirable characteristics
of the final product. Although most people ordinarily do not realize
that there are distinctive flavors in various samples of popcorn, these
are as characteristic as in different varieties of apples. Some strains
have a noticeably sweetish flavor after being popped, some are practi-
cally tasteless, while others have a rather strong field-corn flavor.
High expansion in popcorn is dependent upon complete and normal
maturity in addition to the inheritance of genes conditioning a dense
and elastic endosperm. Since corn diseases usually interfere with
normal maturity, it follows that selection for high popping expansion
also tends to select for resistance to many of the common corn diseases,
such as smut and the stalk and root rots. This is very fortunate for
the breeder, since it is, of course, much easier to make improvements
in a crop in which desirable characteristics are correlated than in one
in which they tend to be mutually exclusive. In the case of popcorn
there seems to be a sound basis for placing considerable emphasis on
the individual ear-popping test, described later in this article.
METHODS AND RESULTS IN BREEDING
Mass Selection
Of the various methods of corn breeding that have been tried from
time to time, that of mass selection alone has stood the test of time
as of general application to improvement within open-pollinated
varieties of corn without resorting to inbreeding. This is as true of
popcorn as of dent corn. Mass selection lends itself particularly to
the improvement of popcorn quality. As in field corn, mass selection
in popcorn begins with field selection of a large number of ears from
desirable plants when the crop is mature but before the first killing
frost occurs. These ears should be dried quickly, but not so thorough-
ly as they would be for seed. About 14-percent moisture gives nearly
maximum popping behavior and insures against loss of viability by
freezing under any ordinary storage conditions.
After being numbered for identification purposes, the ears can be
popped individually by shelling enough from one side of each to fill
a small measure for the popping test. After popping, the volume
of the product is measured in a suitable container so that the ratio of
the volumes before and after popping may be obtained and recorded
as the popping expansion. Unfortunately, a standardized method
of testing has never been agreed on, so that comparisons of popping
tests made by different people sometimes are misleading. In this
laboratory ordinary glass graduates are used, as shown in figure 1.
For individual ear tests a popping charge of 25 cubic centimeters
ordinarily is measured out in a small graduate, and the popped corn
is later measured in a 1,000 cc graduate. Any convenient modifica-
tion of this procedure that will give an accurate measure of the popping
expansion would do just as well. It is highly important, however,
that the tests of the various ears be made under as nearly comparable
conditions as possible. The factors particularly to be guarded are:
398
YEARBOOK, 1937
(1) The moisture content of the ears must remain as nearly constant
as possible for the duration of the tests, since moisture content has
an important influence on popping expansion. (2) The conditions
of popping, such as degree of heat used, absence from drafts, etc.,
should be the same for all tests. (3)
A routine procedure in measuring
the samples before and after pop-
ping should be followed, in order that
the same degree of packing may be
obtained for every sample.
When samples from a consider-
able number of ears from an appar-
ently uniform variety are popped
separately,striking differences in the
popping expansion of the individual
ears will be observed. Usually the
best ears will show about twice the
popping expansion of the poorest
ones. The distribution of popping
expansion of 1,152 individual ears
taken from a small isolated plot in
1928 is shown in figure 2.
By using only the highest 10 or 15
percent of the selected ears for seed
purposes a rather rigid selection on
the basis of popping expansion can
be made. In order to avoid the in-
j urious effects of close breeding in an
open-pollinated variety, care must be
exercised not to limit too greatly the
number of seed ears utilized to prop-
agate the strain. Although it is diffi-
cult to set an arbitrary minimum, a
mixture from not less than 50 ears
should be used to plant the seed plot
each year, and one from 100 or more
selected ears would be much safer.
In following a system of mass selec-
tion, the unpopped remnants of the
most desirable ears are simply
bulked together to furnish seed foran
isolated seed plot the followingyear.
In contrast to the mass-selection
method, the pedigree or ear-to-row
method may be used, in which each
row is planted from a single ear
and a preliminary selection is made on the basis of individual rows,
followed by selection within the row. It is probable that this method
has no advantages over mass selection to counterbalance its disad-
vantages of more labor and greater likelihood of close breeding.
As in all selection work, there is a constant drag of regression toward
the mean of the population in selection for high popping expansion.
Figure 1. — Class graduates used to
measure the volume of popcorn before
and after popping. A popping expan-
sion of about 24 volumes (600-^-25) is
indicated in this sample.
POPCORN
399
16-17 18-19 20-21 22-23 24-25 26-27 28-29 30-31 32-53 34-35
POPPING EXPANSION
Figure 2. — Distribution of 1,152 individually popped ears
of Supergold popcorn harvested from a small breeding
plot. Note that the best ears had about twice the
popping expansion of the poorest ones.
Consequently, one may not expect the average popping expansion of
the crop produced to be nearly so high as the average of the selected
ears that are planted. If the work is carefully and consistently done,
however, some progress in raising the mean is accomplished each time,
and over a period of
years real improvement
may be effected, al-
though such improve-
ment may not be ex-
pected to continue in-
definitely.
In an experiment con-
ducted cooperatively by
the Department and the
Kansas Agricultural Ex-
periment Station to test
theemcacyofmassselec-
tion in popcorn breed-
ing, the popping expan-
sion was increased from
19 to 26 volumes in 6
years. Comparatively
littleincrease in popping
expansion has been ef-
fected since that time,
which indicates that the practical limits of improvement have about
been reached. This work was initiated by J. G. Willier, formerly
assistant agronomist in the Bureau of Plant Industry. The resulting
improved strain, originally known as Sunburst, but later changed to
Supergold, has been distributed by the Kansas station.
Where some attempt at improvement of quality is desired, but
where the labor of popping a large number of individual ears for seed
selection is out of the question, a modification of the mass-selection
method based on kernel structure may be used. A reasonably good
correlation (r=— 0.59 ±0.022) has been found2 between the amount
of soft white starch in the center of the kernel and the popping expan-
sion of the ear from which it came. Since the correlation is negative,
it means that the ears with the least amount of soft starch in the
kernels will on the average pop the best. In selecting seed, three or
four kernels from each ear may be split with a sharp knife to determine
those with the least amount of soft white starch. These ears should be
saved for seed. Although selection for high popability from kernel exam-
ination is much less desirable than from direct popping tests, it is much
better for the maintenance of a good strain than no selection at all.
It is particularly valuable as a means by which to cull out the traces
of mixture with dent corn which tend continually to creep into popcorn
varieties. _, ,r
Popcokn Hybrids
Hybridization between inbred lines, the newest and most promising
method of corn breeding, is equally as applicable to popcorn as to
8 Willier, J. O., and Brltnson, A. M. factors affecting the popping quality of popcorn. Jour.
Agr. Research 35: 015-624, illus. 1927.
400 YEARBOOK, 1937
dent corn or to sweet corn. A general discussion of corn breeding
appears in the 1936 Yearbook of Agriculture,3 in which the methods
and results of hybrid corn production are fully described. With the
exception that popping expansion and eating quality must be given
paramount consideration in popcorn, the technique followed is the
same as for field corn. The possibilities are fully as promising, but
thus far comparatively little work has been done in the production of
popcorn hybrids.
The only hybrid popcorn known to the writer that has been re-
leased for commercial production is Minhybrid 250, from the Minne-
sota Agricultural Experiment Station. Inbreeding of 200 to 250
lines of Michigan Pop, a selection of Jap Hulless, was begun in 1925
by H. K. Hayes and H. E. Brewbaker. Since 1930 the breeding work
has been done by H. K. Hayes and I. J. Johnson. The original
lines were culled severely on the basis of agronomic characteristics,
so that when the first crosses were made in 1929 only seven remained.
These seven inbreds were combined in all possible combinations of
single crosses and tested thoroughly during the 4 years 1930-33. On
the basis of these trials, single cross C-l X 0-6 was selected as the
best combination and named Minhybrid 250. Representative ears
of inbreds 1 and 6 and of the single cross are shown in figure 3. The
component inbreds were distributed in 1934, and small commercial
acreages have been grown in 1935 and 1936. As an average of 3
years' tests at University Farm, Minhybrid 250 has produced 16
percent higher yield and 29 percent higher popping expansion than the
standard open-pollinated Jap Hulless used as a check. The adapta-
tion of this hybrid seems to be limited to central Minnesota. In a trial
in the southern part of the State the hybrid was much less satisfactory.
In 1931, the Minnesota station also started inbreeding a group of
lines from Burbank Pure Gold, a 10-rowed yellow pearl variety.
These inbreds are now just ready for top-cross tests and trials of
recombination.
At the Iowa Agricultural Experiment Station J. C. Eldredge began
inbreeding in 1928 with 50 ears of Jap Hulless, part of which were
selected from a mass selection plot of the previous year and part from
various commercial growers. These lines have been culled to about
20 inbreds between which combinations have been tested during the
period from 1933 to 1936. On the basis of these tests the most prom-
ising hybrid seems to be a three-way cross which has averaged about
a 20-percent increase in yield and a 20-percent increase in popping
expansion over the open-pollinated Jap Hulless used as foundation
material. An extensive State-wide test of this hybrid is planned for
1937. No distribution for commercial production has yet been made
from Iowa.
In 1933 a new group of inbreds from Jap Hulless, South American,
and Supergold were started at the Iowa station, which are still in the
developmental stage.
In 1923, J. G. Willier, of the Bureau of Plant Industry, then at
Washington, D. C, and later at Manhattan, Kans., in cooperation
with the Kansas station, started inbred lines with a yellow pearl
popcorn similar to Queen Golden. Later, C. W. Bower, also of this
3 Jenkins, M. T. coen impbovement. V. S. Dopt. Agr. Yearbook 1936: 455-522, illus. 1936.
POPCORN
401
Bureau, was associated with this work. This investigation was
started mainly as an experiment to compare the efficacy of inbreeding
compared with mass selection and ear-to-row breeding as a means of
popcorn improvement. Careful selection was practiced during the
inbreeding period, both within and among the inbred lines, for
Figure 3. — Representative ears of the two component inbred lines and of the cross in
Minhybrid 250: A, Line C-l; B, line C-6; C, Minhybrid 250.
popping behavior as well as for characters of agronomic importance.
At the conclusion of the work in 1931 it was found that hybrids much
superior to the foundation material had been produced. During the
same period, however, marked improvement in the original variety
had been effected by mass selection, as referred to earlier in this
article, so that when the mass-selection strain was used as the basis
of comparison the hybrids showed no superiority in popping expan-
402 YEARBOOK, 1937
sion, although somewhat higher yields and considerably greater uni-
formity of the crop were obtained.
New and much better inbred lines were beginning to be available
from the strain already improved by mass selection, so it was decided
to drop the original lines and wait until hybrids distinctly superior to
existing open-pollinated varieties in popping expansion as well as in
yield were available before commercializing them. Preliminary
trials of hybrids from this newer material have been very promising,
although the corn failures of 1934, 1935, and 1936 at Manhattan
have greatly retarded the recent development of the work. In a
cooperative field trial near Colfax, 111., m 1935, 19 of 81 hybrids
produced in Kansas had popping expansions of 25.0 volumes or more
in comparison with an average popping expansion of 24.1 volumes
for the parent stock, Supergold, grown in the same test. The highest
popping expansion for any hybrid was 28.5 volumes. Yield was in-
creased even more than popping expansion, the average yield of 72
of the 81 hybrids having uniform stands being 3,218 pounds per acre
in comparison with 2,517 pounds per acre as the average of the Super-
gold checks. Unfortunately, the highest yielding crosses did not
also possess the highest popping expansion, but a few were distinctly
superior to the parent open-pollinated strain in both respects.
The difficulty of combining top yields and superior popping expan-
sion in the same strain or hybrid of popcorn seems to be a common
experience. Apparently the genetic constitution necessary to produce
extremely high yields also produces too much soft starch in the
centers of the kernels for best popping results. Why this is so is not
definitely known. Perhaps the plant is unable, with the plant food
materials at hand, to produce more than a given amount of the col-
loidal matrix in which the starch granules are embedded in the horny
portions of the endosperm, and when greater amounts of endosperm
are produced, increasing proportions are left in the form of soft starch.
If this be the case, the situation is roughly analogous to the difficulty
of obtaining a dairy cow with maximum milk production and maxi-
mum butterfat content in the same individual. Whatever the causes,
it has been the experience of the writer that some compromise must
be made in either yield or popping expansion or both to secure the
best all-round popcorn hybrids from the utility standpoint.
Less loss of vig'or from inbreeding is experienced normally in pop-
corn than in dent corn. Because of the ability to find comparatively
productive inbreds, and because of the small amount of seed required
per acre, it probably will be possible to utilize single crosses largely
in commercial production. The shape of popcorn kernels from
inbreds is about the same as that from their parent varieties, and the
size is usually but little smaller, so that no mechanical difficulties
with corn planters are encountered in using seed grown on inbred
lines in the production of single crosses. The commercial use of
single crosses simplifies hybrid seed-production problems and makes
possible a most uniform market product.
In the limited trials thus far made, popcorn hybrids between inbreds
from different varieties have given the most outstanding increases in
yield. This confirms the experience with dent corn hybrids, where
crosses between entirely unrelated stocks in the main have been
POPCORN 403
most successful. Hybrids between inbreds of Supergold and South
American have given some extremely high yields, but the tendency
toward a negative correlation between yield and popping expansion,
referred to above, has seriously limited the usefulness of most indi-
vidual crosses of this group. A very unusual situation is encountered
in crossing South American and Supergold, in that the combination
is perfectly fertile when South American is used as the pollen parent,
but is almost completely sterile when Supergold is used as the pollen
parent. Utilization of hybrids involving this combination must
therefore be planned so that Supergold may serve as the seed-producing
parent. Demerec4 reports a similar case of sterility in popcorn,
although the varieties involved and the source of material are not
clearly stated. „ T,
Synthetic Varieties
One variant of the inbreeding method, which has interested corn
breeders for some time, is the possibility of recombining a fairly
large number of selected inbreds into a synthetic variety that might
be better than the original variety and which, because of the number
of component lines, could be continued by open pollination without
serious reduction of vigor and yield. Starting about 1920 with obser-
vational plots and yield tests of all available popcorn varieties, J. K.
Duncan, of the Michigan Station, has selected Australian Hulless,
Japanese Hulless, Japanese Dwarf Rice, and Queen Golden as the
most promising varieties for his conditions and has started inbred
lines within these varieties. It is planned to recombine the best
inbreds into two synthetic varieties, one within the hull-less group
and one within the yellow pearl group. Although in field corn no
synthetic variety of outstanding yielding ability has yet been pro-
duced, it should be possible, by rigid selection of the inbred lines on
the basis of popping expansion, to produce in popcorn a synthetic of
high quality. No results of the Michigan experiment are as yet
available, but its progress is being watched with interest.
Breeding for Resistance to Diseases and Insects
Resistance to disease is an important consideration in popcorn
breeding. Any parasite that saps the vitality of the plant or prevents
complete and normal maturity of the grain tends to lower popping
expansion. Moreover, the diseases generally grouped as the ear rots
are particularly objectionable, since occasional moldy kernels are
very undesirable and. are practically impossible to separate from corn
after it is shelled. The majority of commercial popcorn dealers and
processors sort the corn by hand before it is shelled, in an attempt to
eliminate diseased ears. Frequently, however, portions of ears with
early stages of infection are not easily recognized, and although such
corn frequently will pop, it has distinctly undesirable flavors.
No project dealing specifically with breeding for disease resistance
in popcorn is known to the writer, although in practically all work,
both with open-pollinated varieties and with hybrids, attention is
given to freedom from diseases as one of the bases of selection. In the
many field-corn hybrids produced experimentally from which the
'Demebec, M. cross sterility in maize. Ztschr. Induktive Abstain, u. Vererbungslehre 50: 281-
291. 1929.
404 YEARBOOK, 1937
commercial hybrids now in production represent a small and highly
selected portion, there has been marked variation in quality. It is
likely that just as wide a range of disease resistance will be found in
popcorn hybrids. Some of the experimental popcorn hybrids referred
to above are very distinctly superior to open-pollinated varieties in
freedom from diseases.
Insect damage also is very objectionable in popcorn and is severely
discriminated against by the trade. Corn earworms are the cause
both of direct damage to the grain and of indirect damage through
secondary infestations by other insects and infections with ear rots.
Injury by the corn earworm and by storage insects is particularly
severe in the Southern States, where it is a serious problem, especially
in popcorn, which is used primarily as human food.
At the Texas Agricultural Experiment Station, P. C. Mangelsdorf
is attempting to combine the superior resistance of some southern
varieties of field corn with the popping ability of popcorn. Of the
varieties tried, Yellow Creole has given the most promise of transmit-
ting insect resistance without interfering with popability. By means
of a series of crosses, backcrosses, and recombinations coupled with
rigid selection, progress is being made and hopes are entertained that a
desirable popcorn may result that will be resistant to grain injury by
insects. GENETICS AND CYTOLOGY
The genetics and cytology of popcorn are the same as for other sub-
species of Zea mays. These subjects have been discussed in the article
already referred to in the 1936 Yearbook of Agriculture,5 to which
attention is directed for detailed information. As a matter of fact,
many of the testers used in unraveling the linkage relations in corn have
been popcorns or popcorn derivatives. Popping behavior is unques-
tionably a heritable character, but it is probable that it represents one
of the more complex cases of quantitative inheritance conditioned by
many genes.
» Jenkins, M. T. See footnote 3.
BREEDING AND GENETICS
IN POTATO IMPROVEMENT
F. J. STEVENSON, Senior Geneticist,
C. F. CLARK, Horticulturist, Division
of Fruit and Vegetable Crops and
Diseases, Bureau of Plant Industry
Wh
/HEN the Spaniards invaded South America they found a large
number of varieties and species of potatoes under cultivation, the
tubers of which were used as a common article of food by the natives.
Where these varieties and species originated is not well known, but
they seem to be native to the American Continent, since their relatives
are still to be found growing wild on the elevated regions extending
from the southwestern part of the United States to the southern part
of South America, particularly on the higher altitudes in Bolivia and
Peru and the coastal regions and nearby islands of southern Chili.
All the species seem to require a cool climate, since they are found
growing at high latitudes in regions near the Equator and none is known
to occur under tropical conditions.
INTRODUCTION INTO EUROPE AND NORTH AMERICA
If the origin of the potato is uncertain, its introduction into Europe
and North America is also shrouded in mystery. Many interesting
legends have been written concerning this, but few reliable facts are
available. It is not hard to believe that the Spanish sailors, on their
return from their many trips to the New World, brought back potatoes
and introduced them into Spain and Portugal. That these were the
common potato known, today and not the sweetpotato is proved
definitely by a report of Clusius published in his Rariorum Plantarum
Historia in 1601, giving an illustration and description of a plant sent
him in 1588 by the Governor of Mons. The flowers were light purple
and the original plant obtained by Clusius produced a fruit ball and
two reddish tubers. From Spain and Portugal the potato was taken
probably to Italy, from there early in the seventeenth century to
Austria, then to Germany, from Germany to Switzerland, and finally
to France. The legends surrounding the introduction into Ireland
have a more romantic setting. They are centered around Drake,
one of Queen Elizabeth's pirates, who was encouraged by the Queen
to plunder Spanish ships and Spanish possessions. It is supposed
that on one of these trips Drake obtained potatoes in the West
Indies for his ship's stores and that some of these were carried to
Ireland about 1586.
Little is known of the introduction of the potato into North America.
It is generally believed that the English colonists of Virginia and
Carolina obtained the potato from Spaniards or from other travelers.
The most authentic report shows that potatoes were first grown in this
country at Londonderry, N. H., in 1719, from stock brought from
405
406 YEARBOOK, 1937
Ireland. It was for this reason, no doubt, that the potato was called
the "Irish" potato. The name is still used, especially in the South,
where it serves to distinguish the potato from the sweetpotato.
Most of the stories of the introduction of the potato into Europe
and North America are no doubt legendary, as well as some of the
tricks that were supposed to have been adopted to get people to use
the tubers for food. The spectacular increase of the potato as a food
crop, however, is not legendary, but is one of the miracles of agricul-
ture. Although it is only a little over 300 years since the first intro-
duction into Europe and about 200 years since the first importation
into the United States from Ireland, the potato is now grown in almost
every important agricultural country in the world. The crop for the
United States and Canada for 1934-35 was nearly half a billion
bushels, and the total for the world, not including the Union of
Soviet Socialist Republics and China, for which no data are available,
had reached the stupendous figure of over 6 billion bushels.
BOTANICAL RELATIONSHIPS
The potato belongs botanically to the section Tuberarium (SO) 1 of
the genus Solarium, the members of which are, with few exceptions,
tuber bearing. This section comprises not only the cultivated forms
but many wild species. Since it is probable that undiscovered species
occur in regions not yet explored by botanists, the total number cannot
be definitely stated, but it is believed to exceed 100.
1 Italic numbers in parentheses refer to Literature Cited, p. 434.
MILLIONS of dollars are spent each year in providing ways and
means of protecting the potato crop from diseases, and these colossal
efforts have done their part in providing the consumer with potatoes
fit for consumption; but in spite of them, many millions of bushels
are lost each year. The annual loss from late blight alone has aver-
aged 9,000,000 bushels for the past 10 years. Thus disease re-
sistance has been a major objective in the well coordinated national
potato-breeding program now being conducted throughout the United
States, in which the Department of Agriculture and all interested
States closely cooperate. Already many varieties have been ob-
tained resistant to late blight, to scab, and to two of the mosaic dis-
eases. The results indicate that by using genetic principles as a
working tool, it should be possible to solve many if not all of the
disease problems of potato growers by combining resistance with
superior qualities of economic importance, such as shallowness
of eye, desirable shape, good cooking quality, high yield, and
adaptability to local conditions.
POTATOES 407
Considerable confusion has existed in the past in regard to what
has been considered the species Solarium tuberosum L., which has
generally been understood to comprise all cultivated varieties of po-
tato. These have recently been assigned by Bukasov (9) to 14 species.
According to his classification, S. tuberosum includes the Chilean culti-
vated forms as well as the commercial varieties of North America and
Europe, which he believes to be of Chilean origin. Most of the com-
mon cultivated varieties of the Andes region are placed in the species
S. andigenum Juz. and Buk. The 12 remaining species are grown in
small local areas in the Andean countries and more or less resemble
the wild species in their general appearance. It is doubtful whether
any of the cultivated varieties of Europe and North America as known
today have been derived from them.
EARLY IMPROVEMENT IN THE POTATO
There is little information available regarding the source of the potato
stock grown during the first 100 years after its introduction into the
United States. It is believed that not many new varieties of impor-
tance were produced during that period. During the second century
of potato culture in this country, however, there was great activity
in the production of new varieties. Data reported on 228 of these
varieties show that they originated in 21 States. New York and
Vermont, however, produced 50 percent of the total number. Of the
160 varieties whose date of origin is known, 80 percent were produced
during the 40-year period 1861 to 1900 and 48 percent during the two
decades 1871 to 1890 (i#).
The most important varieties produced during this 100-year period
and their originators, as reported by Stuart (7jQ, are given in the
appendix.
Special mention should be made of C. E. Goodrich, as his work
was the first to produce lasting results. He believed that the dis-
astrous epidemics of late blight during the years 1843-47 were the
result of a reduction in the vigor of the plants caused by long-continued
propagation by vegetative means and that this vigor could be re-
stored by growing plants from true seed. While he did not succeed
in the control of late blight by this means, he may be considered to
have laid the foundation of potato breeding in this country by fur-
nishing material to be used by other breeders. The ancestry of 170
varieties can bo traced back to Goodrich's Garnet Chili, a seedling
of the imported Rough Purple Chili. They include several of
the well-known varieties of commerce, such as Beauty of Hebron,
Burbank, Early Ohio, Early Rose, Green Mountain, Prolific, and
Triumph.
The work of Pringle, as recorded by Stuart (71), is outstanding in
that it represents what is believed to be the first systematic effort to
obtain seed by controlled hybridization. This seed was not only used
for the production of the varieties ho introduced but was disseminated
to others through his contract with a seedsman in New York to furnish
hybridized seed at $1,000 a pound.
Many varieties of excellent quality and high yielding ability, which
were the principal objectives, were produced during this period. The
work, which made important contributions to the agriculture of this
408 YEARBOOK, 1937
country, was carried on entirely by private agencies rather than by
public institutions. Most of the men engaged in the early work were
practical potato growers, except C. E. Goodrich, who was a clergy-
man, of Utica, N. Y., and E. S. Carman, who was editor of the Rural
New Yorker. PRESENT-DAY PROBLEMS
The commonly grown commercial varieties of potatoes differ from one
another in earliness, tuber shape, adaptation, depth of eye, cooking
quality, and yielding ability. In certain of these characters, such as
yielding ability, some of these varieties have reached a high standard
of excellence when grown under conditions to which they are adapted.
These same varieties are, however, poor in other characters. Some are
not adapted to a wide range of conditions; others have deep-eyed
tubers, which cause waste in preparing the potatoes for cooking. All
are susceptible to one or more of the common potato diseases, includ-
ing the virus diseases, late blight, common scab, fusarium wilt,
rhizoctonia, early blight, and blackleg. Control of these diseases
requires a continual fight on the part of the potato grower and adds
greatly to the cost of producing the crop.
The group of diseases caused by viruses are perhaps the most wide-
spread and the most baffling. In this group are found mild mosaic,
latent mosaic, leaf roll, spmdle tuber, and yellow dwarf. These
diseases occur in every potato-growing region of the United States,
and it is probable that not a single field could be found entirely free
from them. They are not new. Their effects have been observed
by growers for many years, but for a long time it was thought that they
were due to "running out" or "degeneracy", brought about by grow-
ing potatoes year after year from the same tuber stock. It is only a
few years since it was discovered that these troubles are due to virus
diseases. It was soon observed that some varieties did not "run out"
so quickly as others, or, as we now say, some varieties are more
resistant to the attacks of certain viruses than others. Knowing
that such differences must have a genetic basis, breeders are working
to obtain resistance to these diseases in combination with other
characters of economic importance.
Late blight, caused by Phytophthora infestans (Mont.) DBy., adds
more to the cost of producing the potato crop than perhaps any of
the other diseases. The losses from this disease alone have been
more than 9 million bushels a year for a period of 10 years, according
to estimates issued by the Division of Mycology and Disease Survey,
Bureau of Plant Industry, United States Department of AgriciUture.
In some seasons and in certain localities the disease causes very little
damage. At other times (as in 1927, 1928, 1932, and again in 1936)
large losses are sustained by growers. The heaviest loss for any one
year, nearly 31 million bushels, was reported in 1928. That year
late blight was reported in 15 States, with the loss in New York esti-
mated at approximately 13 million bushels. In 1932 the reduction of
the crop was estimated at 9,230,000 bushels, the greater part of
which, 9,058,000 bushels, was reported from Maine. Again in 1936
heavy losses occurred in Maine.
It is true that late blight can be controlled to a large extent by
careful spraying with bordeaux mixture, but despite the fact that
POTATOES 409
control measures are being practiced more generally than ever and
that spray equipment has been improved and spray programs have
been more faithfully carried out, large losses continue to occur, not
only from reduction in yields but also from interference with market-
ing operations. Rot may develop on infected tubers in storage and
in transit. Because of the uncertainty involved, the buyer is reluctant
to purchase potatoes for storage purposes. There is considerable
expense every time a carload is regraded at a terminal market, and
this happens frequently in blight years. These losses all affect the
grower.
Common scab, caused by Actinomyces scabies (Thax.) Gues., is
another disease that takes a toll from the grower. The organism
causing this disease lives over in the soil and is also carried on the
tubers. Treatments have been recommended that will kill the
organisms on the tuber, but no one has yet devised a method to fully
protect the growing tubers from the soil-borne organisms.
Millions of dollars are spent each year in providing ways and means
of protecting the crop from the attacks of these and other diseases,
but comparatively little attention has been paid to obtaining varieties
resistant to the attacks. The colossal efforts in the way of plant
protection have done their part in providing the consumer with
potatoes fit for human consumption, but in spite of these efforts millions
of bushels of potatoes are lost each year. Residts already obtained
indicate that by using genetic principles as a working tool it should
be possible to solve many if not all of these problems by producing
new varieties in which resistance to various diseases is combined with
other characters of economic importance, such as shaUowness of eye,
desirable shape, good cooking quality, and high yield.
In the production of such varieties the plant breeder must be
familiar with the local problems of growers; he must have a knowledge
of the existing varieties and the important economic characters of
each; and he must be familiar with the botanical structure and
behavior of the various parts of the growing plants. A knowledge of
the modes of reproduction with the advantages and limitations of
each is the first essential.
REPRODUCTION IN THE POTATO
The potato plant is reproduced in two ways. In commercial practice
it is grown from tubers, a method of vegetative or asexual reproduc-
tion. Plants can be grown from true seed, however, by sexual repro-
duction. . „
Asexual Reproduction
A number of mutations in the vegetative cells of potatoes have been
studied and described, but they are too few and far between to be
relied upon in a breeding program as the only source of variation. In
many cases, too, the changes are of minor importance. Clark (IS)
has described several mutations that have occurred in the color of the
skin and of the eyes. Salaman (57) classifies mutations of this sort
according to whether they are due to the acquisition or to the loss of a
character and whether they affect the tuber only or the whole plant.
Mutations due to the loss of a character are by far the most common.
There are a number of instances where the red tuber loses part of its
138904°— 37 27 + +
410
) I Hi It 00 K, 1937
color and becomes "splashed", or loses nil of its color and becomes
white. Purple tubers may become red, purple splashed, or white.
Somewhat similar changes have been observed for flower color.
Mutations due to the acquisition of a character, which might be called
positive mutations, are much rarer. Examples are a red-tubered
sport from a whitc-tubered variety, or a fully colored one from a
partially colored variety. Mutations occurring in more than one
character in the same individual arc extremely rare. Mackelvie (38)
reports such a case in which there was a whitc-tubered mutation com-
bined with a different leaf shape from that of the parent variety. The
Figpre 1. — Potato plants grown from true seed in the greenhouse. These plants have
hecn transplanted from the germination pots to individual pots where they will he
grown until they are transplanted in the field.
leaflets of the mutant were narrower and more pointed. The yield
was reduced also.
East (22) carried out some rather carefully controlled studies on
the occurrence of somatic or vegetative mutations in the potato. In
these studies each variety was started from a single hill. During the
course of the study five permanent changes from pink to white tubers,
two permanent changes from long to round tubers, and four instances
of changes from shallow to deep eyes were observed. Selection for
high nitrogen content gave negative results.
Clark (/#) made a study of six commercial varieties to determine
whether their origin could bo accounted for by mutation. The
methods employed were those reported by Asseyeva (1) for this
purpose. They consisted of removing from the eyes of the seed pieces
POTATOES 411
the outer layers of tissues, which, in skin-color mutations, are the
mutating tissues. This allowed the sprouts from which the plants
under test were grown to develop from the deeper layers, the original
unchanged tissue. Clark found that four of the varieties studied were
mutations in the outer layers of the tuber. Two were mutations from
smooth skin to russet skin, the third was a mutation from colored to
colorless skin, and the fourth from colorless to colored skin.
That the occurrence of such mutations has not been an important
factor in the development of potato varieties is shown by Clark (12),
who reported that of 380 varieties that have originated in the United
States and have at one time or another been introduced to the com-
mercial trade, 306, or 93.3 percent, were of seedling origin, and only
22, or 6.7 percent, were reported as so-called sports or mutants. Of
the 22 varieties reported as sports, 4 are white-tubered from varieties
with colored tubers, and 4 are late-maturing variations found in early
varieties. The meager information regarding the other 14 furnishes
no basis for determining whether they were actual mutations or mix-
tures carried in the seed stock or volunteers that had persisted in the
soil from some preceding crop.
Even if only a few varieties have arisen as the result of somatic
mutations, they are still a source of variation that cannot be ignored
entirely by the breeder.
Since it is quite impracticable for the plant breeder to make much
improvement by selecting tubers of a variety with the hope of getting
something new, he has to resort to the use of seed as a means of induc-
ing variations. _ _,
" Sexual Reproduction
As has been shown by Clark (12), most of the varieties that have
originated in the United States were produced by growing plants from
true seed (fig. 1). Salaman (55), discussing the production of new
varieties from the same source in England, states: "It is by this
method that practically every variety which has ever been raised since
the introduction of the potato in 1588 has been attained."
True seed is a product of sexual reproduction and is found in the
fruit or ball, which is quite similar to a small tomato (fig. 2). Under
certain conditions these fruits are produced in abundance on some
varieties but are rarely if ever seen on others. They are the result of
the maturing of the flower, and each of them may contain 200 seeds
or more.
The flower of the potato is what is known to botanists as a complete
flower with calyx, corolla, stamens, and pistil. There are usually five
stamens surrounding the pistil. The process of pollination is very
simple because of the simple structure of the flower parts. Pollen
may be brought to the stigma of the pistil in several ways. In varie-
ties in which the pistil is the same length as the stamens or shorter,
the mature anthers may come in direct contact with the stigma. When
the pistil is longer than the anthers, pollen may fall upon it when the
flower droops over, as it frequently does at the end of the day. Insects
may be responsible for a much greater amount of cross-pollination
than is commonly supposed ; in some localities bumblebees and honey-
bees are often seen visiting potato flowers. Pollination may be
effected also by the manipulations of the plant breeder.
412
) /•; iH BOOK, 1937
<
The technique of cross-pollinating potatoes by hand is compara-
tively simple, but since relatively few varieties produce viable pollen,
the setting of seed is often very small in amount. If a variety produc-
ing viable pollen is used as the female parent, the flower must be
emasculated, that is, tlie anthers must be removed. This must be
done before the anthers
are mature, or the
flower will be self-polli-
nated. Generally
speaking, the anthers
should be removed be-
fore the pistil protrudes
through the bud, or a
day or two in advance
of the opening of the
flower. A pair of sharp-
pointed forceps is the
only instrument nec-
essary. All the flowers
in the cluster that are
in the right stage of
maturity are emascu-
lated, all others are
removed, and the inflo-
rescence is enclosed in
a 1-pound paper bag,
which is securely tied
on. If the variety
used as the female par-
ent does not produce
viable pollen, it is not
necessary to emascu-
late before pollinating.
In pollinating,
flowers with anthers
ready to open are ob-
tained from the male
parent. These are
placed on the thumb-
nail and the anthers are
tapped gently with the
forceps. The stigma
of a seed parent is then
gently rubbed in the pollen on the thumbnail until it is completely
covered (fig. 3). The treated flowers are covered with the paper bag
again. It has been found best to enclose as much foliage with the
flowers as possible, to protect them from injury and to supply moisture;
otherwise the flowers may dry up and fall off. The failure or success
of the fertilization can be determined within a week or 10 days (fig. 4).
As soon as the seed balls develop, the paper bags are removed
and replaced by a cheesecloth sack, which is tied securely to the
vines
Figure 2. — Potato seed balls, the result of natural polli-
nation of a variety that produces fertile pollen.
POTATOES
413
Every breeding method has its advantages and limitations, and
which one or which combination is used depends to a large extent on
the problem involved in a particular case. The potato breeder today
uses (1) the introduction of new varieties or species, (2) selection of
clonal lines, (3) varietal crossing, (4) sib mating (brother-sister mating),
(5) backcrossing to parental lines, (6) selfing and recombining selfed
lines, (7) outcrossing to unrelated lines, (8) strain building, and (9)
crossing of different species.
Since a discussion of these steps and methods involves a number of
rather technical points, it will be postponed until later in this article,
Figure 3. — Pollinating potato flowers.
after the work now being done in potato breeding in the United
States has been outlined.
THE NATIONAL POTATO-BREEDING PROGRAM
Becaltse of the effect of environment on the fruitfulness (seed pro-
duction) of potato plants, it is difficult, if not impossible, for many of
the State experiment stations interested in some aspect of potato-
breeding work to produce true seed. This would prevent the applica-
tion of genetic principles to breeding problems and close the most
promising avenue for their solution. Certain Northern States and
other States with mountainous regions where potatoes can be grown
at high elevations are especially favored, since true seed of many
strains and varieties, as well as tubers of good quality, relatively free
414
YEARBOOK, 1937
from disease, can be produced in such places. In potato breeding,
then, more perhaps than in any other breeding project, it is neces-
sary that the interested States cooperate in their attacks on the
many problems involved.
Organization of the Work
Since problems and objectives in potato breeding often cut across
State lines and involve large regions of the entire country, the breed-
ing work has been organized as a national project with all the inter-
ested State experiment stations and the United States Department of
Agriculture cooperating. A number of the cooperating stations are
Figure 4. — Seed balls 8 days after the pollination operation shown in figure 3. These
fruits are the source of seeds from which new varieties are produced.
now carrying on complete breeding programs — that is, they are able
to produce true seed and raise seedling progenies for genetic analysis of
the material they are interested in, and at the same time to produce
improved varieties. The States of Minnesota, North Dakota, Michi-
gan, New York, Louisiana, and North Carolina and the Department
working in Maine and Colorado are at present producing true seed.
If any of these find they can use more seed than they are able to
produce, a supplementary supply is sent from Maine, Minnesota, or
Colorado, or from any other State that has a surplus. True seed
is also sent to other States not able to produce their own, such as
Iowa, and in 1936, Nebraska and Wisconsin. The last two States
have recently undertaken complete potato-breeding programs.
A number of States that do not grow potato seedlings test the most
promising seedling varieties produced by others. New introductions,
POTATOES 415
parent material, and tubers representing seedling progenies are
distributed to any State experiment station that can make use of
them. The Department has been active in the production and
distribution of such material and by common consent of the cooperators
has been designated as the coordinator and clearing house for the
project as a whole. A brief outline of the work carried on at the
various stations under this project follows.
For a number of years the Department workers have been carry-
ing on an intensive program of potato breeding at Presque
Isle, Maine, in cooperation with the Maine Agricultural Experi-
ment Station. As a part of the national potato-breeding program
they are now engaged in (1) the production of true seed for use
at Presque Isle and for distribution to other cooperating experi-
ment stations; (2) distribution of single-tuber selections of various
progenies to cooperating stations; (3) distribution of named and
numbered seedlings for tests at other stations; (4) yield trials; (5)
disease-resistance tests, including resistance to mild mosaic, latent
mosaic, spindle tuber, leaf roll, late blight, and common scab; (6)
genetic and cytological studies; and (7) the production of early-
maturing varieties. In all this work higher market and cooking
quality are being considered.
The work at the United States Horticultural Station, National
Agricultural Research Center, Beltsville, Md., is interwoven with
that carried on at Presque Isle and at other stations included in the
national potato-breeding program. Two of the important aspects
of the work at this station are the production of seedlings and the
testing of seedling progenies and parents for resistance to virus diseases
such as mild mosaic, latent mosaic, leaf roll, and spindle tuber. Tests
are also made in the greenhouse for resistance to late blight and to the
attacks of Fusarium eumartii Carp, and in the field for resistance to
F. oxijsporum Schl. Resistance to blackleg is being studied in certain
progenies.
Iowa produces seedling progenies from seed furnished from Maine
arid Minnesota and tests the promising material produced by other
cooperating States for its adaptability to Iowa conditions.
Louisiana produces some of the seed used in the production of
seedling progenies. Other seed and material are supplied by Minnesota
and the Department. Resistance to various diseases and adaptability
of potato varieties to southern conditions are being emphasized.
The work in Michigan consists of growing seedling progenies,
testing Department seedlings and those produced by other cooperating
stations, increasing new varieties, carrying on disease-resistance
studies with special reference to yellow dwarf and common scab, and
producing early varieties with better market and table quality and
varieties more suitable for muck soils.
In Minnesota securing resistance to virus diseases and to common
scab in combination with early maturity is the main problem. A study
of inbreeding and the recombinations of inbred lines is being carried on,
and also a study of the cytological behavior of species hybrids.
In New York (Cornell University) resistance to late blight, using
an immune wild species as the parent from which to obtain resist-
ance, is one of the objects of the breeding work. Tests for resistance
416 YEARBOOK, 1937
to streak and leaf roll are being conducted. A much enlarged program
is just now getting under way, which will emphasize market quality,
cooking quality, adaptability, and resistance to a number of diseases
other than late blight.
In North Carolina the work consists of the production and testing
of seedling progenies produced at Raleigh and the testing of the most
promising material grown at other stations. The emphasis is being
placed on earliness and on resistance to disease and to leafhopper
injury.
North Dakota produces some true seed but is supplied for the
most part from Presque Isle, Maine. Varieties as early as Irish
Cobbler but smoother and higher yielding are being sought.
The Department workers at Greeley, Colo., are attacking the
problems of resistance to wilt, to psyllid. yellows, and to common
scab in relation to other characters of economic importance.
In Nebraska potato-breeding work has only recently been started.
Earliness, yield, quality, and resistance to diseases will be empha-
sized. To begin with, resistance to fusaria is being studied.
In Wisconsin a complete breeding program has recently been
undertaken. Studies of the breeding behavior of resistance to com-
mon scab and virus diseases, as well as of other characters of com-
mercial importance, are getting under way.
In Charleston, S. C, at the United States Regional Vegetable
Breeding Laboratory, breeding work recently initiated will deal
with the problems of potato production in the coastal region of the
Southern States, which center around yield, earliness, and drought
resistance.
In Pennsylvania, at Drifton, a test project for potato wart resistance
is conducted by the State Department of Agriculture in cooperation
with the United States Department of Agriculture. A number of the
most promising named and numbered seedling varieties are tested
for resistance to this disease each year in soil infested with organisms
that cause the wart disease.
In Florida, at Hastings, the Florida Agricultural Experiment
Station has begun the study of resistance to brown rot in the potato
in cooperation with the Department. A few varieties and seedlings
have already been tested, and the experiment will be greatly enlarged
in 1937.
In Indiana, Purdue University has recently initiated a program of
breeding for disease resistance as a part of the national potato-breeding
program.
In addition to the special problems enumerated above, the follow-
ing States are cooperating to determine the adaptability of the new
named and numbered seedling varieties produced by the Department
or by any of the State experiment stations: California, Connecticut,
Florida, Indiana, Iowa, Kansas, Louisiana, Maryland, Massachu-
setts, Minnesota, Michigan, New Hampshire, New Jersey, New York
North Carolina, North Dakota, Ohio, Oregon, Rhode Island, South
Dakota, Tennessee, Virginia, Washington, and Wisconsin.
The cooperative potato-breeding work has not stopped at national
boundaries, for material has been exchanged with a number of workers
in Canada and other foreign countries.
POTATOES 417
Recent Results with Various Methods of Breeding
Clonal Selection
Progress has been made by the use of clonal selection in the State
of New York. According to a recent unpublished report by J. R.
Livermore, one of the cooperators in the national potato-breeding
program, this method has been employed in connection with potato
improvement work at Cornell University in cooperation with growers
since 1905. Four varieties have been selected from the Smooth Rural
(Rural New Yorker No. 2) and named. These are Heavyweight,
No. 9, Pioneer Rural, and Toanco 4. A strain of Irish Cobbler has
been named Pioneer Cobbler. Many other high-yielding clonal lines
have also been selected from commercial varieties and are being pro-
duced by various growers. White-skinned bud sports from russet
stock, the plant tops exhibiting heat resistance and the rugged vigor
of the Russet Rural, have also been found. The Red Warba, one of
the varieties recently introduced by the Minnesota Agricultural
Experiment Station, occurred as a bud mutation from the Warba.
This might be considered a clonal selection. By the method of careful
selection within a variety or clon, not only are mutations uncovered
but disease-free material is obtained, which in itself is justification
for careful observation and selection.
Inbreeding and Recombination of Selfed Lines, Etc.
F. A. Krantz, of the University of Minnesota, another of the coop-
erators in the national potato-breeding program, has been placing
greater emphasis than other breeders on the method of selection in
selfed lines and recombinations between them. The results have been
very similar to those found by the corn breeders, that is, selfed lines
become homozygous and are less vigorous than the parent stocks
from which they originated. Certain undesirable characters have
segregated and been eliminated, such as short internodes, prostrate
plants, simple-leaved types, chlorophyll deficiencies, and tuber abnor-
malities. MostJ important from the breeding standpoint, a number
of self-fertile lines carrying desirable characters have been selected.
In a brief unpublished summary of results to date, Krantz says:
Selection in self-fertilized lines has been effective in establishing pollen fertility
in combination with a wide variety of other characters. Used in combination with
outcrossing it has facilitated the development of a large body of seed-setting
material possessing selected germ plasm of the common varieties.
The results show that it will be possible through this method gradually to
combine the best germ plasm in the potato into a useful form for breeding pur-
poses. The difficulties involved are the absence of information on the best
selection technique and the necessity of developing one suitable for effectively
selecting and combining desired characters. Pollen sterility at the outset also
presented a serious problem since selection was restricted to the seed setting indi-
viduals. The difficulties mentioned are associated with potato breeding in
general and are not specific to any particular method. Information is gradually
accumulating on methods and technique of selection in inbred lines. The difficulty
of maintaining and continuing inbred lines has been greatly reduced through
selection for high fertility. Comparisons have been made and are in progress of
varietal crosses, single crosses, three-way crosses, and top crosses to determine
the relative hybrid vigor that might be expected from the different types of combi-
nations. The inbred lines are valuable for their concentration of desirable char-
acters in combination with pollen fertility, early maturity, upright sturdy vines,
resistance to certain virus diseases, fine cooking quality, and varying rest periods.
418 YEARBOOK, 1937
Species Hybridization as a Method of Obtaining Late Blight Resistance
and Frost Tolerance
Most of the attempts to produce blight-immune varieties of com-
mercial value by the use of species hybrids have resulted in failure.
Kecently, however, Donald Reddick, of Cornell University, also a
cooperator in the national potato-breeding program, has been getting
promising results from such hybrids. For a number of years it had
been known that certain forms of Sotanum demissum Lindl. were
immune to late blight. In 1928 Reddick began using hybrids between
these and cultivated varieties in an attempt to combine this immunity
with characters of the cultivated forms. Two years later the Depart-
ment sent Reddick and three men from the Division of Plant Explora-
tion and Introduction, C. O. Erlanson, Paul Russell, and M. J. Sou-
viron, on an expedition to Mexico to find, if possible, more sorts of
potatoes, either wild or cultivated, that might be resistant to this
disease. A large number of collections were made. Among these
several varieties of S. demissvm were found to be immune and to have
at the same time some frost tolerance.
In commenting on the methods and some of the difficulties that arise
in this work, Reddick says:
The object has been to get the blight immunity and frost tolerance of a wild
plant into a plant of commercial value. Owing to sterility, incompatability, etc.,
the results thus far have been simply what could be got, not what it was planned
to get. Efforts have been made from the beginning to determine the mode of
inheritance of blight immunity and frost tolerance, but inability to obtain sets of
seeds of the kind desired has prevented determining the mode. The original
crosses are interspecific and involve hybridizing 72-chromosome plants with those
having 48 chromosomes. Practically all of the crosses have had to be 48 male to
72 female, because the reciprocal cannot be effected. The second generation of
such crosses does not segregate but "reverts" to the wild type. Repeated back-
crossing eliminates most of the wild characters but blight immunity is transmitted.
This work has been in progress since 1928. Some of the families
are progenies resulting from an original species hybrid between an
immune species and a cultivated variety that has been backcrossed to
cultivated varieties four successive times. Fifty percent of the
progeny of the fourth backcross are immune to the late blight disease.
As a result of this work Reddick has at the present time about 500
families of plants immune to late blight. Possibly 50 or more of these
are approaching the commercial ideal as to size, color, shallowness of
eye, heat tolerance, and date of maturity. They are still to be tested
for yield, quality, and adaptability to various localities. A few of
these families will stand at least four degrees of frost.
Results in Relation to Disease Resistance
Resistance to Virus Diseases
The potato breeders and pathologists of the Department, using the
methods included in strain building (p. 429), are making real progress,
both from the standpoint of scientific knowledge and of practical
results in breeding for resistance to virus diseases. One variety
produced, U. S. D. A. seedling 41956, is highly resistant if not immune
to the virus of latent mosaic. It has been exposed to the disease in
the field by being grown near other varieties known to have this
POTATOES 419
disease, and diseased stocks of other varieties have been grafted on
the stems and on the tubers, but so far it has withstood every attack.
A number of the progeny of a cross in which this variety was used as
one of the parents show the same character, which indicates that
immunity to latent mosaic is heritable. A number of other seedling
varieties are resistant to this same virus in the field-exposure tests but
contract the disease in tuber-graft tests, where it is expressed as top
necrosis or death of the top of the plant. On the other hand, several
attempts have been made to find even a single plant of Green Moun-
tain free from this disease, but up to the present time such attempts
have resulted in failure.
A large number of seedling varieties are highly resistant in the
field tests to another virus disease, mild mosaic, perhaps the com-
monest of the "running out" diseases. These varieties have all
contracted, the disease, however, in the more severe tests of tuber
grafting. In comparison with these resistant types, Green Mountain
has been known to become 100-percent diseased with mild mosaic in
the field exposure tests within a period of 3 years.
The fact that two virus diseases can be controlled by the production
of resistant varieties gives hope that other virus diseases, such as
spindle tuber and leaf roll, can be controlled in a similar manner.
Comprehensive field-exposure and tuber-graft tests of a large number
of seedlings and. varieties are being made at the present time to
determine whether any of them are resistant to either of these latter
diseases. So far the results have not been encouraging. Although
there have been a few escapes in the field-exposure tests, it is quite
possible that none of the varieties so far tested is resistant to either
of these diseases. Some of them may carry recessive factors for
resistance, however, and many of them will be analyzed genetically
to determine whether this is the case, and if it is, efforts will be made
to combine the resistance with other characters of importance to the
grower. In the case of leaf roll, a few recent introductions are
reported to be resistant and will be used in future work. At the same
time, the search in the United States and in foreign countries will be con-
tinued until types resistant to every virus disease are obtained or until
all the possibilities for finding resistance are completely exhausted.
Resistance to Late Blight, Derived from Cultivated Varieties
Breeding for resistance to late blight was begun at a comparatively
early date. In 1870 Darwin attempted through the use of species
hybrids to produce varieties resistant to Phytophthora, but was evi-
dently not successful. According to Stuart (71), the first American
breeder to attempt the control of late blight by the introduction and
production of blight-resistant varieties was Chauncey Goodrich, of
Utica, N. Y., whose work has already been mentioned. This work
was based on a small quantity of South American potatoes that he
received in 1851 through the American consul at Panama. A number
of other breeders made valuable contributions during the latter part
of the nineteenth century, but with the exception of the work of
Goodrich, resistance to late blight seems not to have been emphasized
in the United States until potato breeding was actively undertaken
by the Department in 1910.
420 YEARBOOK, 1937
According to Clark et al. (18), the only disease resistance sought at
the time was to the late blight fungus. This work had not progressed
very far, however, when it became evident that the virus diseases had
to be given the chief consideration, and it was not until the present
national potato-breeding program was under way that emphasis could
be placed once more on breeding for resistance to late blight. Reddick,
working in cooperation with the Department, had already undertaken
the solution of this problem, using species hybrids. The Federal
work at Presque Isle, Maine, and Beltsville, Md., includes the genetic
analysis of the cultivated varieties to determine the possible existence
of blight-resistant factors.
In 1932, when late blight caused the loss of over 9 million bushels
of potatoes in Maine, 700 seedlings, representing 4 different progenies,
and about 100 Green Mountain checks, were grown at Presque Isle in
test rows of from 20 to 30 hills each. This plot, about 1% acres in
area, was not sprayed with bordeaux mixture but was sprayed in July
with a single application of calcium arsenate to kill the Colorado
potato beetle. Late blight infection was first observed on July 22.
Conditions favorable for the spread of the disease prevailed during
August, so that by the first week in September nearly all the seedlings
and all the Green Mountain checks were completely killed, both leaves
and stems. A few seedlings had stems and about one-fifth of the
leaves remained free from blight infection, and a still smaller group
had only a few infected leaves. There were no seedlings completely
free from the disease. A number of the most resistant lines were
found in a progeny of Katahdin, naturally fertilized. A few seedlings
of the cross Chippewa X Katahdin, both of which are susceptible to
blight, escaped with very little injury. From this test it was evident
that there are different degrees of resistance; that resistant varieties
can be obtained by inbreeding certain susceptible varieties and by
crossing two susceptibles. The test showed also that lateness is not
completely correlated with blight resistance or escape, since all the
seedlings were comparatively late, but hundreds of them were killed
bj blight before they had time to mature.
Since 1932 a large number of varieties and seedlings have been
tested for resistance, some of them at Presque Isle, Maine, and some
in the greenhouse at Beltsville, Md., under conditions favoring heavy
infection. At Presque Isle blight spores are sprayed on the plants
under test on evenings preferably cool and damp. In the greenhouse
steam is turned into the section in which the plants are being tested, to
produce a high humidity, and the plants are then sprayed with spores
of the fungus. Heavy epidemics are usually induced by these methods,
and unless a variety is resistant, there is little chance of escape. A
number of introductions from Germany and elsewhere, as well as a com-
paratively large number of progenies, have been put through these
tests during the last 4 years. The results obtained with some of these
were reported by Stevenson et al. (67) and need not be repeated here.
It should be said, however, that there are now available hundreds of
varieties and seedlings showing varying degrees of resistance to late
blight. A few produced from seed received from K. O. Miiller, Berlin-
Dahlem, Germany, have completely escaped infection, even under
epidemic conditions such as prevailed in the Presque Isle tests in 1936.
POTATOES 421
From the commercial standpoint one of the most promising selec-
tions up to the present time is from a cross of Chippewa X Katahdin.
This variety came through the epidemic of 1932, unsprayed with
bordeaux mixture throughout the growing season, with very slight
injury. It has been included in the greenhouse tests at Beltsville and
again in the field at Presqtie Isle in 1936 and produces a good crop,
even when sprayed with blight spores. It has yielded slightly more
than Green Mountain for an average of 5 years at Presque Isle and
has good cooking quality when grown at Aroostook Farm. Other
promising seedlings highly resistant to blight are from a cross between
No Blight and Katahdin. No Blight is described by Bonde (6)
under the name Foster Rustproof, and Katahdin has been described
by Clark et al. (18). No Blight is quite resistant to. late blight.
Katahdin is susceptible, but it carries a factor or factors for resistance
in a heterozygous condition, as io shown by the fact that blight-
resistant seedlings have been found in a progeny of Katahdin selfed.
Some of the blight-resistant seedlings from the cross No Blight X
Katahdin are being tested for yield and other characters. Two
years' tests show them to be in about the same class as Green Moun-
tain with respect to yield. Another cross from which a number of
promising selections have been made had for parents Ekishirazu, a
Japanese variety, and seedling 45349, the latter a seedling of Katahdin
open-pollinated. Seedling 45349 was selected in 1932 and has shown
a fair degree of resistance in a number of tests since that time.
Figure 5 shows the difference between the appearance of the vines
of a resistant seedling on which very little late blight developed and
the Green Mountain check, which was completely killed by the disease.
Both of these were sprayed with blight spores to induce the epidemic.
The tubers of a number of the seedling varieties are resistant to
tuber rot caused by the late blight fungus. Reiner Bonde, of the,
Maine Agricultural Experiment Station, has tested a number of them
by putting blight spores on the surface of the tubers and then placing
them in a moist chamber in a temperature conducive to development
of rot. A number of the seedling varieties remained free from rot
except where the skin was broken. The Green Mountain check rotted
completely in a very short time (fig. 6). Many varieties therefore
have been produced within the last few years by hybridization and
selection that are resistant enough to late blight to be grown success-
fully without being sprayed even in years when this disease occurs in
epidemic proportions. Several of these are promising also from the
standpoint of other characters of commercial importance.
Resistance to Common Scab
Another disease that takes its toll wherever potatoes are produced
is the common scab caused by Actinomyces scabies. Scab is not so
noticeable in its effects on yields as is late blight, but it affects the
market quality and hence the value of the tubers.
The behavior of a comparatively large number of varieties under
widely different conditions indicates that resistance to scab occurs in
the potato in varying degrees. Complete immunity has not as yet
been demonstrated. Concerning this point, Berkner (8) says that
absolute immunity does not appear to exist, but that there are decided
422 YEARBOOK, 1937
hereditary differences in the degrees of resistance and susceptibility.
The nature of resistance to scab has been studied by several in-
vestigators. The fact that the varieties that have shown the highest
degrees of resistance possess a thick russet skin has led some to believe
that resistance is dependent upon this type of skin. Histological
studies of several varieties by Lutman (37) led him to conclude that
thickness of skin determines the resistance of the tubers to scab and
that color does not play an important role. Stuart (70) showed the
fallacy of the prevailing conception that the russet type of skin is the
basis of freedom from scab and pointed out that scab was abundant
Figure 5. — Two seedlings of a progeny segregating for resistance to late blight: No. 319
(left) practically free from late blight; no. 320 (center) completely killed by this
disease. At right, susceptible Greeu Mountain check. August 21.
on the tubers of Cambridge Russet during a period of 6 years. In
tests of a large number of seedlings, Darling, Leach, and Krantz (21)
found a high degree of resistance in smooth and thin-skinned seed-
lings as well as in russet types. No correlation was shown to exist
between color of tuber and scab resistance.
Some of the American commercial varieties, such as Russet Rural,
Russet Burbank, and Mahr Russet, have been known for a number of
years to be resistant to scab. A number of European varieties,
Richter Jubel, Arnica, Hindenburg, Oststarke, Treff As, Rhcingold,
and Ostragis, are also resistant, as was reported by Schlumberger
(62, 63). These varieties, with the addition of a U. S. D. A. seedling,
no. 44537, which is highly resistant to scab, have become the basis of
breeding for resistance to this disease. At Presque Isle, Maine, a largo
POTATOES
423
number of other varieties also have been tested for the purpose of
obtaining additional material. The first tests, 1930-33, were con-
ducted on land that was known to produce scabby potatoes in pre-
vious years. The results were somewhat variable. In 1934-36 lime
was applied, before planting, at the rate of about 1 ton per acre, to
land that was known to produce some scabby potatoes in previous
seasons.
In the tests five hills of the variety or seedling to be tested were
planted in alternate hills with Green Mountain, which is susceptible
to scab. Comparisons were made between the seedling or variety
and the Green Mountain check. The material included in these tests
Figure 6. — Resistance of tubers to late blight. Sound tubers, seedling no. 336-302;
decayed tuber, Green Mountain. Both lots artificially inoculated with spores of
the organism that causes late blight.
consisted of varieties of North American, European, and Asiatic
origin, a collection of South American varieties obtained by the
MacMillan-Erlanson expedition, and a number of progenies resulting
from selling certain varieties, as well as progenies from crosses.
Several of the European varieties, including Hindenburg, Richter
Jubel, Ackersegen, Arnica, and Hindenburg X Centifolia No. 9,
which had been introduced because of their resistance to this disease,
proved to be highly resistant in the scab test plots. All of these
produced less than 1 percent of the amount of scab found on the
Green Mountain checks. None of them had enough scab lesions on
the tubers to classify them as scabby potatoes, while the Green
Mountain tubers could not have been sold for table stock.
Golden, a new variety recently produced by the Department, was
found in the 1935 tests to have about one-fifth as much scab on the
424 YEARBOOK, 1937
tubers as was_ found on the Green Mountain checks. A few North
American varieties — Russet Rural, Russet Burbank, and Mahr Rus-
set— were intermediate in their resistance. A relatively large number
of crosses have been made in an effort to determine the breeding
behavior of some of these varieties. Although the data will not
permit the formulation of an exact genetic hypothesis, a number of
facts have been brought out in these tests. The progeny of a cross
between two scab-susceptible varieties, Columbia Russet and Katah-
din, were all susceptible. Another cross between two resistant va-
rieties, Ostragis and Hindenburg, produced a progeny in which all
were resistant to scab. Other crosses between resistant varieties
showed segregation for resistance in the first generation.
Figure 7. — Resistance to common scab. The second and third tubers, seedling no.
416-50, are highly resistant to this disease. The first and fourth tubers are from
the Green Mountain cheek grown in the hills adjacent to the seedling variety.
A heavily russeted seedling variety, no. 44537, proved to be highly
resistant to scab. This variety produces good pollen and is self-
fertile. A progeny of the variety, selfed, segregated for resistance
and russeting. A number of the russeted types and a few of the
smooth white-skinned segregates were resistant to scab. This va-
riety has been crossed with susceptible and resistant varieties. The '
progenies of certain combinations segregated for resistance and sus-
ceptibility. Figure 7 shows a resistant segregate in comparison with
the Green Mountain check. One of the most promising progenies
from the standpoint of both resistance and vigor resulted from a
cross between Richter Jubel and seedling no. 44537. This progeny
segregated for russet and smooth skin and for resistance and suscep-
tibility to scab. A large number of both the russet and the smooth
types were resistant to scab. A number of these were desirable from
the standpoint of shape, depth of eye, color of tuber, and vigor, as
well as scab resistance, and were selected for future work. It is too
soon to predict their commercial possibilities, but some of them are
the most promising scab-resistant seedling varieties produced so far.
POTATOES 425
Practical Rkstjlts
The foregoing results show progress. A practical accomplishment
has been the distribution within the last 5 years of six new varieties of
potatoes. Others are on the way. Warba and Red Warba have been
distributed by the University of Minnesota, and four varieties —
Katahdin, Chippewa, Golden, and Houma — by the Department.
"Warba is an early variety, and from reports from different sections
of the country it seems to be outstanding among the early varieties
in yielding ability, lied Warba has not been tested thoroughly,
but it is assumed to be similar to Warba in all its characters except
color, since it originated from that variety as a vegetative mutation.
The four new varieties distributed by the Department in cooperation
with the State experiment stations are all resistant to the virus
disease mild mosaic, which causes so much running out of the Green
Mountain variety in Maine. Chippewa is being increased as rapidly
as the available supply of seed stock will permit. It is medium early,
has high yielding ability, and is widely adapted. Golden is a yellow-
fleshed variety, like most of the potato varieties used for food in
Germany. There is a limited demand for this type in the United
States, and Golden is being grown by 50 or 60 growers in Maine and
by a few in the Upper Peninsula of Michigan. The variety is not
widely adapted, but where it can be grown successfully it is prized
because of its very high yields, good cooking quality, and scab
resistance.
Houma was selected from a group of U. S. D. A. seedlings grown
at Iloumaj La., by J. C. Miller, of the University of Louisiana,
because of its high quality and adaptation to the Houma potato-grow-
ing section of that State. The season just past showed this variety to
be somewhat drought resistant, but not sufficiently so to withstand
the severe drought in the Middle West.
Katahdin (fig. 8) was the first variety to be introduced by the
Department, and for that reason it is the most widely known of the
Department introductions. It has had its ups and downs but is
still on the increase. In a recent bulletin Moore and Wheeler (40)
say in part:
An outstanding characteristic of the Katahdin that should appeal to most
Michigan growers is its ability to produce satisfactory yields of good type tubers
even under heat and drought conditions. The Katahdin sets fewer tubers per
hill than the Rurals and develops them earlier. This characteristic often enables
it to surpass Rurals in yield of marketable potatoes, particularly when the season
is unfavorable for the Rural varieties. The results of tests and the experiences
of many growers confirm this statement.
Four seasons unfavorable for Rurals but in which Katahdins have
been grown successfully have occurred in Michigan since 1930.
This is no doubt responsible for the fact that most of the 500,000
bushels of Katahdins grown in Michigan in 1935 were kept for the
1936 planting, although it is not definitely known how the market
will receive this variety. Preliminary tests have shown that the
Katahdin as grown in Michigan is superior to the standard varieties
in market quality and is equal at least to the Rurals in cooking
quality. In the fall of 1935, 53 bushels of Katahdin were distributed
in bushel lots to 53 hotels in Michigan, Ohio, Illinois, and Indiana.
138004°— !t7 28
426
YEARBOOK. 193 7
Fourteen hotels had a few criticisms to make. Thirty-nine reported
that they found the Katahdin an excellent potato for baking, boiling,
and frying, and that they were well pleased with the color and texture
of the cooked product. Many of the hotel chefs made favorable
comments on the attractive appearance of the Katahdin and were
Figure 8. — A field of Katahdin. Note vigorous vine growth almost covering rows.
well pleased with its smooth, thin skin and shallow eyes, which reduced
waste in peeling.
These same characteristics, smooth shape and shallow eyes (fig. 9),
combined with the resistance to mild mosaic, induced the representa-
tive of Argentina, looking for seed potatoes in the United States
and Canada, to recommend the purchase of a large quantity of seed
stock of the Katahdin variety for that country. He is said to have
purchased a quantity of Chippewa, too, although the price of these
was comparatively very high. He refused to consider the deeper
eyed types such as Irish Cobbler and Triumph.
The potato-breeding project as it now stands and the results up
to the present time demonstrate clearly the necessity and the advan-
tages of cooperation in scientific enterprises. The project is dependent
on the Division of Plant Exploration and Introduction, Bureau of
Plant Industry, United States Department of Agriculture, for new
material carrying new genes for resistance and other important charac-
ters. Within recent years varieties resistant to late blight, others
resistant to scab, and still others that are said to be resistant to leaf
roll have been obtained. The plant breeders and horticulturists
make the crosses and grow the progenies. The plant pathologists
create the epidemics and secure the disease data. The Bureau of
Home Economics of the Department, assisted by the horticulturists,
makes the cooking tests. The State experiment stations cooperate
in testing the new seedlings produced either by the Department or by
POTATOES
427
any other institutions to determine their range of adaptability. If
any of the investigators find a seedling adapted to growing conditions
in their State they take the responsibility of increasing the seed and
seeing that it is distributed to growers. All these steps are necessary
for the success of the breeding work, and all the organizations share
the credit for its accomplishments.
Figure 'J. — Tubers of llic Kalahdin potato. The good shape of the tubers and the
shallow eyes are outstanding features of this variety.
A summary of the results of breeding work up to the present time
shows:
(L) A largo number of varieties resistant to one virus disease, mild mosaic.
(2) One variety and several of its progenies immune to another virus disease,
latent mosaic.
(3) Many varieties resistant to late blight, several showing commercial pos-
sibilities.
(4) A large number of varieties resistant to scab, too new to predict the possi-
bilities.
(5) One variety as early as Irish Cobbler, but much smoother and with shallower
eyes, being tested by farmers and about ready for naming.
(6) Six varieties named and distributed.
(7) The Katahdin and Chippewa firmly established as commercial varieties
and entering into the South American seed trade because of their attractive'
appearance and disease resistance.
428 YEARBOOK, 1937
BREEDING METHODS, GENETICS, AND CYTOLOGY 2
The introduction of new varieties or species may not appear to be a
plant-breeding procedure, yet it is fundamental to a well-rounded
breeding program. It is improbable that varieties will be found in
foreign countries adapted to any of the potato-growing regions of the
United States, but even if the new introductions cannot compete with
the standard varieties they may carry genes for certain characters
that will make them extremely valuable from the breeding standpoint.
For example, a number of varieties have been introduced recently
from Europe that are resistant to late blight, others that are resistant
to common scab, and still others that are reported to be resistant to
leaf roll. These are being used in crosses for the purpose of combining
the genes for resistance with those for other characters of economic
importance. In the last 30 years approximately 10,000 sorts, in-
cluding commercial varieties, seedling varieties, and species, have been
collected by the Department. Thousands of these have been dis-
carded because they were considered of no value, but others have
provided a wealth of material for the work of potato breeders.
Advantages and Limitations of the Methods Used
Selection is the principal tool of the plant breeder regardless of the
method employed. Selection of clons or strains from a variety has
often been designated as a special method. This method is limited
in its application, since its success depends on the value of the bud
sports or mutations that occur in a variety or clonal line.
Varietal crossing has been universally employed by potato breeders.
As a rule, varieties are heterozygous or mixed in their inheritance for
most characters and they will segregate into different lines when they
are self-pollinated. Because of pollen sterility not all varieties can
be selfed, and the only way to use valuable genes in a self-sterile
variety is to make it a female parent in crosses. If both parents are
heterozygous for the characters under consideration, segregation will
take place in the first generation. Not all possible recombinations of
characters can be expected in the first generation, however, since one
of the parents may be homozygous or pure for some dominant charac-
ter, in which case all the plants of the first generation would resemble
that parent in that particular character. As an example, in some in-
stances the first generation of a late variety crossed with an early may
be all late, no segregation into late and early lines appearing. There
are certain advantages in using crosses between heterozygous ma-
terial, and also certain disadvantages. One advantage is that segre-
gation occurs in the first generation; and if, because of sterility, a
second generation cannot be produced, it may be possible in many
instances to obtain the desired recombination in the first generation.
Another advantage is that combinations differing widely in vigor often
occur when heterozygous parents are used, and individuals are often
found more vigorous than either parent. The main disadvantage in
the use of heterozygous lines as parents is the difficulty of obtaining
exact genetic knowledge of the breeding material.
2Tbis section is written primarily for students or others professionally interested in breeding or genetics.
POTATOES 429
Sib mating, or sister-brother mating, is one system of inbreeding
and is useful for several purposes. It helps to determine the degree
of homozygosity or uniformity of inheritance of a particular line.
Selling each of the sibs would of course give the same information, but
this cannot always be accomplished because of the self-sterility of
many lines. In some cases, too, segregates from a cross between two
sibs are more vigorous than either parent.
Backcrossing is employed to good advantage in potato breeding,
but as most of the parent material is heterozygous, it is not so efficient
as if homozygous lines were available. If the original parents are
homozygous all the plants of the first generations have the same in-
heritance although, they differ in appearance, and a backcross to any
one of them gives essentially the same results as it would to any other.
If parents heterozygous for certain characters are used, the first-
generation hybrids may differ genetically among themselves, and
therefore would give different results in backcrosses. More work
must be done to accomplish the same results when heterozygous
parents are used than would be necessary if vigorous fertile homozy-
gous parents were available. But in any case backcrossing is a useful
method, and it is employed very frequently to obtain certain com-
binations of characters.
Selling is employed at least to some extent by all plant breeders.
Selfing and the recombining of selfed lines is being used extensively by
corn breeders, but potato breeders have depended to a large extent on
other methods to obtain desirable recombinations. The self-sterility
of many clonal lines and the loss of vigor brought about by intensive
selfing are probably two of the reasons why potato breeders have not
generally adopted this method. Another reason is that the potato
as grown commercially is propagated from tubers, and the grower gets
a comparatively uniform crop even if the variety is heterozygous for
certain characters. This is not true with crops propagated from seed,
as these must be genetically uniform in order that a uniform crop
may_ be produced. For genetic studies it likewise is desirable to
obtain homozygous potato lines that are fertile. From the com-
mercial standpoint some of the most promising material is obtained
by selfing one or two generations, selecting the best of these selfed
lines and outcrossing to one of the best commercial varieties. This
method has sometimes been referred to as top crossing.
Strain building is not a method in itself but is a system of breeding
that makes use of all methods. The system can best be described by
an example from the disease-resistance work now in progress at
Presque Isle, Maine. A few blight-resistant varieties were obtained
from foreign countries, and several seedling varieties produced by the
Department were selected that were only slightly injured by the blight
epidemic of 1932 in the breeding plots at Presque Isle. The most
promising of these from the standpoint of blight resistance were
crossed with varieties carrying genes for high yield, good shape, shal-
low eyes, resistance to mild mosaic, and other characters of economic
importance. The progenies were tested for blight resistance, and the
most promising seedlings were selected. Some of these were selfed,
some of them sib-mated, some backcrossed to the resistant parent,
and others outcrossed to unrelated blight-resistant varieties. The
430 YEARBOOK, 1937
resulting progenies were again tested for blight reaction and selections
made, taking into consideration resistance to blight, shape and color
of tuber, depth of eye, and vigor. By such a combination of the
methods of introduction, varietal crossing, sib mating, backcrossing,
and selfing, it should be possible to get any desired recombination of the
genes of the parent cultures. Some of the resulting new varieties thus
produced should be as good as or better than the commercial varieties
in yield, shape of tuber, etc., and superior to them in disease resistance.
The use of species hybrids is usually the last resort of the breeder
interested in the production of superior horticultural varieties. It
is true that in order to do the best work he must be acquainted with
the wild relatives of the plant with which he is working, the characters
they possess, and their behavior in crosses. Research with species
and species hybrids, then, must be one aspect of any breeding project.
It sometimes happens that a desirable character is not to be found
in the cultivated varieties of a crop but is present in a related species,
so that the desired combination of genes can only be obtained by mak-
ing a cross between species. An illustration of this is found in breeding
potatoes for resistance to late blight. At present, although a number
of cultivated varieties are resistant to this disease, none has been
found immune to its attacks. Some of the related species, however,
do show immunity. Attempts have been made from time to time to
combine this immunity with characters of commercial importance by
the use of species hybrids.
By the use of all the available methods, if it were not for sterility,
the number of new varieties that could be produced through recom-
binations would be limited only by the characters of the available
parents and the number of offspring it is possible to grow.
Sterility a Major Handicap
Sterility, or lack of fruitfulness, which is very generally present in
potato varieties, is the source of the greatest difficulty in sexual breed-
ing, and in spite of much study of the condition it remains the greatest
handicap of the potato breeder.
Salaman (51, 52) and Heribert-Nilsson (24) found sterility of the
anthers to be dominant to fertility. At first Salaman believed sterility
was due to a single gene, but later Salaman and Lesley (59) indicated a
more complex manner of inheritance. Edzell Blue, a variety that
produces viable pollen, was heterozygous on its female side for male
sterility. Krantz (32) points out that two commercial varieties,
Green Mountain and Early Ohio, have produced fertile seedlings in
progeny grown from self-fertilized seed. The Green Mountain variety
usually sets some seed under favorable growing conditions. The Early
Ohio variety sets no seed. It apparently produces viable pollen under
very favorable circumstances.
Kessler (27) described a number of morphological characters of the
pollen of various varieties and their relation to its germinating power.
Neither the shape in itself nor the amount of granulation was an
indication of sterility. A much surer test was obtained by staining with
carmine in hydrochloric acid. The sterile pollen remained unstained.
The influence of culture media, air, humidity, temperature, and light
was considered. Light had an adverse effect, as had also temperatures
POTATOES 431
above 95° and below 46° F. Studies of pollen tube development after
artificial pollination indicate that the pollen tube of a particular
variety may reach the ovule successfully when applied to certain
varieties but not when applied to others.
Clark (14) enumerates four different types of plant sterility — pre-
mature abscission or dropping of buds and flowers, lack of viable
pollen, hybridity, and physiological incompatability between parents.
Premature abscission constitutes a very effective type of sterility,
since it is obvious that fruit cannot be produced when buds fall before
opening or flowers persist for only a few hours. If this is not very
pronounced, so that a few flowers open and persist for a few days, they
may, under favorable climatic conditions, produce fruit when pol-
linated with viable pollen. The anthers of such flowers produce little
pollen, and this is rarely, if ever, viable.
Pollen sterility is very strongly manifested in the cultivated varieties
of potatoes. This condition appears to be inherent in the species.
Stout and Clark (68) studied the pollen of 170 commercial varieties
and 513 seedling varieties, representing material from many parts of the
world. They failed to find a single variety in which there was not a
fairly large percentage of sterile pollen. Of seven wild species studied,
only one, Solanum commersonii Dun., showed the presence of this
type of sterility to any marked degree.
Salaman (SI) demonstrated the hereditary nature of sterility in
potato a number of years ago. He stated that the potato plant, which
is normally bisexual, carries a dominant factor that inhibits pollen
formation at the pollen mother cell stage or even earlier. In a later
paper Salaman and Lesley (59) showed by reciprocal crosses that the
greater portion, if not all, of the sterility is inherited through the
female parent. The fact that the eggs are often viable under con-
ditions lethal to the pollen is well known and makes possible the use
of many varieties as seed parents that cannot be used as pollen parents.
Irregular chromosome behavior has been advanced by a number of
investigators as one of the chief causes for hereditary sterility.
Longley and Clark (36) presented a study of chromosome number
and of meiotic behavior in tuber-bearing forms of Solanum. In 37
cultivated varieties grown in the United States there was found a
somatic chromosome number of 48. The meiotic behavior of this
group varied from regular in a few cases to extremely irregular in many
of the varieties. Only the few varieties with a regular chromosome
behavior produced an appreciable amount of viable pollen; varieties
with an irregular chromosome behavior produced practically no pollen.
Genetic factors and chromosome behavior no doubt make the
development of sterility possible, since varieties are inherently different
in the degree to which they will bloom or set seed. But seed setting
is also influenced by environmental factors to a marked degree.
Some varieties will set seed under a wide range of conditions, while
others have never been known to set seed even under favorable con-
ditions. Stow (69) showed that environmental conditions even
influenced the chromosome behavior. He stated that — •
the abnormal division is neither connected with the hybrid nature of the plant
nor the nutritive correlation within its body; but is rather due to the environ-
mental conditions or certain special nature of the plant itself.
432 YEARBOOK, 1937
He considered that sterility was mainly the result of abnormal pollen
mother cells, which he observed with exposure to high temperatures
(25°-35° C). "At lower temperatures (15°-20° C), on the other
hand, the reduction proceeded in a regular manner, producing normal
pollen grains."
That length of day has an influence on flowering and seed setting
has been shown by Stevenson and Clark (66). In the experiment
reported by them that was conducted in the greenhouse at the Arling-
ton Experiment Farm, Arlington, Va., the application of artificial light
for 5 hours to 20 potato varieties to supplement the daylight period
stimulated vine growth and blossoming to a remarkable degree. The
varieties used in this experiment were grown also in the field at
Presque Isle, Maine, where 10 of them produced seed in varying
degrees of abundance, while the remaining 10 produced no seed. In
the greenhouse experiment at Arlington, 70 percent of the plants in
the 10 more responsive varieties came to full bloom under the lights,
while only 5 percent of the checks without lights bloomed. In the
less responsive varieties only 20 percent of the plants under the lights
bloomed, and no blossoms were produced by the check. No naturally
fertilized seed was produced, but inbred seed was readily obtained
under the lights by hand-pollinating self-fertile plants. The chromo-
some behavior of the plants grown under the light was much more
regular than that of the same varieties grown without lights.
The effect of environment on blooming was shown by Stout and
Clark (68). Halved tubers of 15 varieties were grown, one set at
Presque Isle, and the corresponding halves at the New York Botanical
Garden. All the varieties bloomed profusely at Presque Isle. In
New York only 2 of these varieties bloomed well, 3 produced a few
flowers, and 10 produced no flowers that opened. Conditions are
favorable for seed setting nearly every season at Presque Isle. A few
other places in the United States have been found favorable for seed
production in potatoes. At Estes Park, Colo., which has an elevation
of 7,500 feet, seed sets in most years quite readily. Another striking
example of the effect of environment is found in the potato-breeding
work in Minnesota. Seed cannot be produced on a large number of
varieties and strains at University Farm, St. Paul, but many of the
same varieties will produce seed at Duluth on Lake Superior, and even
better at Castle Danger on the north shore of the lake.
Complete or partial sterility may result from hybridizing, though
there seems to be no general rule regarding the behavior of hybrids
with respect to sterility, as some combinations produce hybrids with
a very high degree of fertility, while the progeny resulting from other
crosses may be completely sterile. In a species cross between Solarium
■fendleri A. Gray and S. chacoense Bitt., produced by Clark (15), the
first generation was completely sterile when selfed and when back-
crossed with either parent. Bukasov (10) reports that hybrids of
S. acaule Bitt. with S. andigenum and with $. tuberosum are sterile.
In some species of plants certain combinations of crosses within the
species as well as selfed pollinations fail to produce seed even though
there is no degeneracy_ in either pollen or egg cells. Other combina-
tions in the same species may produce an abundance of fruit. This
type of sterility has been referred to as physiological incompatibility.
POTATOES 433
It was not found to occur in the cultivated varieties of potatoes studied
by Stout and Clark (68), but was reported by Clark (14) to be present
in the wild species Solanum caldasii glabrescens Dun. and S. chacoense.
Genetics of the Potato
Definite genetic data are available for only a comparatively few
characters of the potato. Such data are accumulating from year to
year, however, and as the knowledge grows the solution of many
breeding problems becomes less complex. A partial summary of
potato characters, their genetic behavior, the name of the investigator
making the report, and the literature citations are given in the
appendix.
A study of the table shows the usual array of gene interactions —
dominance and recessiveness, complementary genes (either 2 or 3),
multiple genes, cumulative effects, and inhibiting genes.
In several instances a number of different ratios are reported for
what is apparently the same character; but it must be remembered
that characters that look alike may be genetically difFerent and as a
result will behave differently in inheritance.
From the material available it is seen that little is known concern-
ing the genetic behavior of some of the most important characters of
the potato, such as yield, cooking quality, and resistance to various
diseases, but the breeding work is being centered around such char-
acters at present, and it is believed that, while they may be rather
complex in their genetic behavior, they will all follow the general rule
that a genetic character is the end result of the interaction of genes
and environment.
Potato Species, Their Chromosome Numbers, and Some of Their
Valuable Characters
"While it is necessary for the breeder to obtain a thorcmgh knowledge
of the cultivated varieties and their important economic characters,
it is also important to know the related wild forms and species of
potatoes, It is true that new genes and gene combinations are being
brought to light in the cultivated varieties, but it is quite improbable
that all the problems can be solved by the recombinations of genes
available in this group.
Much work has already been done with the species of Solanum
related to the potato, and a fund of valuable information is available
concerning them. The species fall into five groups with respect to
In chromosome numbers, those having 24, 36, 48, 60, and 72 in
vegetative tissues, as reported by several investigators. According
to Bukasov (9), cultivated varieties have been found in the first four
groups. Crosses between species with different chromosome num-
bers are as a rule difficult to obtain. For example, crosses between
species of the 24 group and the 48 group are very rare, although
many attempts have been made to produce them. Certain species
crosses have been reported, however, and as knowledge increases
concerning the causes of incompatibility and sterility, it may be
possible in the future to get hybrid combinations that at present seem
quite impossible. A partial list of species of the Tuberarium section of
Solanum, with their 2n chromosome numbers, is given in the appendix.
434 YEARBOOK, 1937
Characters that would be especially valuable if they could be com-
bined with those of the best commercial varieties have been found in
a number of species. Among these are resistance to drought, frost,
potato wart, viruses, and late blight. The characters for short-day
development and short rest period are found in some of the species
also. The character for short-day development might be valuable
in potato districts where the crop is grown during the winter months
under conditions of short-day length. A list of the species known to
possess valuable characters from the breeding standpoint is also
given in the appendix.
LITERATURE CITED
(1) ASSEYBVA, T.
1927. BUD MUTATIONS IN THE TOTATO AND THEIR CHIMERICAL NATURE.
Jour. Genetics 19: 1-26, illus.
(2) Bartosh, J.
1930. UNTERSUCHUNGEN ZUR GENETIK DER KARTOFFEL. III. UNTER-
SUCHUNGEN UBER DIE VERERBUNG DER KNOLLENGESTALT BEt
der kartoffel. Arb. Bio!. Reichsanst. Landu. Forstw. 18:
117-151.
(3) Berkner, F.
1933. DIE URSACHEN DES KARTOFFELSCHORFES ITND WEGE ZU SEINER
bekampfung. Landw. Jahrb. 78: 295-342, illus.
(4) Black, W.
1930. NOTES ON THE PROGENIES OF VARIOUS POTATO HYBRIDS. Jour.
Genetics 22: 27-43, illus.
(5)
1935. STUDIES ON THE INHERITANCE OF RESISTANCE TO WART DISEASE
(SYNCHYTRIUM ENDOBIOTICUM (SCHILB.) PERC.) IN POTATOES.
Jour. Genetics 30: 127-146.
(6) Bonde, R.
1932. a promising blight resistant potato. Amer. Pot. Jour. 9:
49-54.
(7) Bukasov, S. M.
1932. frost resistance in the potato. Trudy Prikl. Bot., Genetiko i
Selek. (Bull. Appl. Bot., Genetics, and Plant Breeding) (2) 3:
[287]-297, illus. [In Russian. English summary, pp. 296-297.]
(8)
1933. REVOLUTIONARY METHODS IN THE BREEDING OF POTATOES. 42 p.,
(g\ illus. Leningrad. [In Russian.]
1933. THE POTATOES OF SOUTH AMERICA AND THEIR BREEDING POSSI-
BILITIES. Bull. Appl. Bot., Genetics and Plant Breeding.
Sup. 58, 192 pp., illus. [In Russian. English summary, pp.
(10) - 154-192.]
1934. [the great crisis in potato breeding.] Trudy Prikl. Bot.,
Genetike i Selek. (Bull. Appl. Bot., Genetics, and Plant
Breeding) (A) 10: [51]-60, illus. [In Russian. Translated
title.]
(11) and Lechnovitz, V.
1935. importancia en la fitotecnia de las papas indigenas de la
America del sur. Rev. Argentina Agron. 2: 173-183, illus.
(12) Clark, C. F.
1925. THE development of potato varieties IN THE united states.
H3) Potato Assoc. Amer., Proc. 12: 5-8.
1927. some instances of bud mutation in the potato. Potato Assoc.
Amer. Proc. 14: 35-38.
(14)
(15)
1927. types of sterility in wild and cultivated potatoes. Mem.
Hort. Soc. N. Y. 3: 289-294.
1929. A SOLANUM HYBRID RESULTING FROM A CROSS BETWEEN S. FENDLERI
and s. chacoense. Jour. Heredity 20: 391-394, illus.
POTATOES 435
(16) Clark, C. F.
1931. 'JHB ORIGIN BY MUTATION OF SOME AMERICAN POTATO VARIETIES.
Potato Assoc. Amcr. Proc. 17 (1930): 117-124.
(17) and Stevenson, F. J.
1935. PHE BREEDING BEHAVIOR OP THE KATAHDIN POTATO. Amor.
Potato Jour. 12: 55-59.
(18) — , Stuart, W., and Stevenson, F. J.
1931. the katahdin potato; a new variety. Amer. Potato Jour. 8:
[121]-125.
(19) Collins, E. J.
1921. t:"ie problem or the inheritance of immunity to wart disease
in the potato. Gard. Chron. 70: 260, 271, 290, 314, 326, illus.
(20) Collins, F J.
1924. inheritance of the colour fattebn of THE KING EDWARD
potato. Jour. Genetics 14: 201-202.
(21) Darling, H. M., Leach, J. G., and Krantz, F. A.
1935. scab resistance in potato seedlings. (Abstract) Phytopa-
thology 25: 13-14.
(22) East, E. M.
1910. inheritance in potatoes. Amer. Nat. 44: 424-430.
(23) Fruwirth, C.
1912. zub zuchtung der kartoffel. Deut. Landw. Presse 39: [551]—
552, 565-567, illus.
(24) Heribert-Nilsson, N.
1913. potatis fSuadling och potatis bedomning. W. Weihulls
Arsbok 8: 4-31, illus. [Review in Ztschr. Prlanzenziichtung
1: 240-242.]
(25) Huber, J. A.
1930. genetische versuche mit salatkartofflen. Ztschr. Zi'ichtnng
(A, Pflanzenziichtung) 15: [75]-85.
(26) Kelly, J. P.
1924. SEED progeny of a potato with faintly coloured tubers.
Jour. Genetics 14: 197-199.
(27) Kessler, E., von.
1930. DEE POLLEN VON SOLANUM TUBEROSUM L., SEINE KEIMFAHIGKEIT
und das wachstum der pollenschlauche. Angew. Bot. 12:
[362J-418.
(28) Kovalenko, G. M.
1932. [hardy frost- resist ant potato varieties.] Trudy Prikl. Bot.,
Genetike i Sclek. (Bull. Appl. Bot., Genetics, and Plant Breed-
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(29) and Sidorov, F. F.
1933. [inter-species hybridization of the potato.] Trudy Prikl.
Bot., Genetike i Selek. (Bull. Appl. Bot., Genetics, and Plant
Breeding (A) 7: [97]-106. [In Russian. Translated.]
(30) Kovalev, N. V.
1933. [a contribution to the question of breeding the potato for
resistance to phytophthora.] Trudy Prikl. Bot., Genetike i
Selok. (Bull. Appl. Bot., Genetics, and Plant Breeding) (A) 7:
[91]-96. [In Russian. Translated title.]
(31) Krantz, F. A.
[1923.] the application of genetic principles to potato breeding.
(32) Amer. Soc.- Hort. Sci. Proc. (1922) 19: 124-129.
1924. potato breeding methods. Minn. Agr. Expt. Sta. Tech. Bull.
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1925. GENETIC STUDIES IN POTATOES. I. THE INHERITANCE OF PARTI-
COLOR AND SUFFUSED TUBER COLOR. Potato AsSOC. Amer.
(34) Proc. 12: 32-37.
1924. GENETIC STUDIES IN POTATOES. II. THE INHERITANCE OF RED
cortical color in tubers. Potato Assoc. Amer. Proc. 13:
52-55.
(35) and Hutchins, A. E.
1929. potato breeding methods, ii. selection IN INBRED LINES.
Minn. Agr. Expt. Sta. Tech. Bull. 58, 23 pp., illus.
436 YEARBOOK, 193 7
(36) Longley, A. E., and Clark, C. F.
1930. CHROMOSOME BEHAVIOR AND POLLEN PRODUCTION IN THE POTATO.
Jour. Agr. Research 41 : 867-888, illus.
(37) Lutman, B. F.
1919. resistance op potato tubers to scab. Vt. Agr. Expt. Sta. Bull.
215, 30 pp., illus.
(38) Mackelvie, D.
1922. bud variation. Intcrnatl. Potato Conf. Roy. Hort. Soc. Rept.
London, p. 35.
(39) Matsuura, II.
1933. A bibliographical MONOGRAPH ON PLANT GENETICS (GENIC
analysis) 1900-1929. Ed. 2, rev. and enl., 787 pp. Sapporo,
Japan.
(40) Moore, H. C, and Wheeler, E. J.
1936. the katahdin potato in Michigan. Mich. Agr. Expt. Sta. Spec.
Bull. 271, 15 pp.
(41) MtJLLER, K. O.
1923. ZUR KENNTNIS DER FAKTOREN DER ANTHOZYANBILDUNO BEI DER
kartoffel (vorlaufige MiTTEiLUNG). Ber. Deut. Bot. Gesell.
,,n\ 41 ( General versammlungs-hef t) : (60-66).
1928. UNTERSUCHUNGEN ZUR GENETIK DER KARTOPFEL. Arb. biol.
,.n\ Reichsanst. Land. u. Forstw. 15: [177]-213, illus.
1930. UBER DE PHYTOPHTHORARESISTENZ DER KARTOPFEL UND IHRE
VERERBUNG. (ZUGLEIGH EIN BEITRAG ZUR FRAGE DER POLY-
PLOIDIE BEI DER KARTOFFEL.) Angew. Bot. 12: 299-324.
(44) Oppenheimer, H. C.
1933. CYTOGENETISCHE UNTERSUCHUNGEN AN BASTARDEN KNOLLEN-
TRAGENDER SOLANUM ARTEN. I. SOLANUM CHACOENSE BITT.
X solanum tuberosum l. s. str. Ztschr. iiidiiktive Abstain, u.
Vererbungslehre 65: [72]-98, illus.
(45) Orton, C. R., and Weiss, F.
1921. THE REACTION OP FIRST GENERATION HYBRID POTATOES TO THE
wart disease. Phytopathology 11: 306-310.
(46) Pissarev, V.
1933. KARTOFPELSELEKTION AUP KALTERES1STENZ. Ztschr. Ztichtung
(A, Pflanzenzuchtung) 18: [582V-594, illus.
(47) Rasumov, V.
1935. [frost resistance of some potato species.] Trudy Prikl. Bot.,
Genetike i Selek. (Bull. Appl. Bot., Genetics, and'PIant Breed-
ing) (3) 6: 221-226. [In Russian. Translated title.]
(48) Rybin, V. A.
1930. karyologische UNTERSUCHUNGEN an einigen wilden UND ein-
heimischen kultuvierten kartofpeln amerikas. Ztschr.
/^g\ Induktive Abstam. u. Vererbungslehre 53: [313]-354, illus.
1933. CYTOLOGICAL INVESTIGATION OF THE SOUTH AMERICAN CULTIVATED
AND WILD POTATOES, AND ITS SIGNIFICANCE FOR PLANT BREEDING.
Tradv Prikl. Bot., Genetike i Selek. (Bull. Appl. Bot., Genetics,
and Plant Breeding) (2) 2: 3-100, illus. [In Russian. English
summary, pp. 97-98.]
(50) Rydberg, P. A.
1924. THE SECTION TUBERARIUM OF THE GENUS SOLANUM IN MEXICO AND
central America. Bull. Torrey Bot. Club 51: 145-154, 167-176.
(51) Salaman, R. N.
1910. MALE STERILITY IN POTATOES, A DOMINANT MENDELIAN CHARACTER;
WITH REMARKS ON THE SHAPE OF THE POLLEN IN WILD AND
domestic varieties. Jour. Linn. Soc. Bot. 39: 301-312.
(52)
(53)
(54)
1910. THE INHERITANCE OF COLOUR AND OTHER CHARACTERS IN THE
potato. Jour. Genetics 1 : 7-46, illus.
1912. A LECTURE ON THE HEREDITARY CHARACTERS IN THE POTATO.
Jour. Roy. Hort. Soc. 38: 34-39.
1913. studies in potato breeding. 4th Conf. Internatl. Gen6tique,
Paris, 1911, Compt. Rend, et Rapports, pp. 373-376.
POTATOES 437
(55) Sat, a Han, 11. N.
1926. potato varieties. 378 pp., illus. London.
(56)
(57)
1928. THE INHERITANCE OF CROPPING IN THE POTATO. 5th Intematl.
Kong. Vererbungswiss., Berlin, 1927, Vorhandl. 2: 1240-1253,
illus.
1931. somatic mutations in the potato. 9th Internatl. Hort. Cong.
Loudon, 1930, Rcpt. and Proc, pp. 117-140, illus.
(58) and Lesley, J. W.
1920. GENETIC STUDIES IN POTATOES. THE INHERITANCE OP AN ABNORMAL
haulm type. Jour. Genetics 10: 121]— 37, illus.
(59) and Lesley, J. W.
1922. genetic studies in potatoes: sterility. Jour. Agr. Sci. [Eng-
land] 12: 31-39, illus.
(60) — and Lesley, J. W.
1923. genetic studies in potatoes: the inheritance or immunity
to wart disease. Jour. Genetics 13: [177]-186.
(61) Schick, R.
1934. kaktoffelzuchtung. Xaturwissonsehaften 22: 283-285.
(62) Schlumberger, O.
1927. die wiktschaftliche bedeutung des kautoffelschorfes, ziele
und wege zu seiner bekampfung. Illus. Landw. Ztg. 47: 131-
132, illus.
(63)
1934. veksuche zur bekampfung des kartoffelschorfes im jahre
1933. Mitt. Deut. Landw. Gescll. 49: 140-142.
(64) Sirks, M. J.
1929. THE interrelations of some anthocyane-factors in the po-
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(65) Smith, H. B.
1927. chromosome counts in the varieties of solanum tuberosum
and allied wild species. Genetics 12: [84J-92, illus.
(66) Stevenson, F. J., and Clark, C. F.
1933. artificial light as an aid in potato breeding. Amer. Potato
Jour. 10: 103-107.
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Bonde, R.
1936. breeding for resistance to late blight in the potato. Amer.
Potato Jour. 13: 205-218.
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1924. sterilities of wild and cultivated potatoes with reference
to breeding from seed. U. S. Dept. Agr. Bull. 1195, 32 pp.,
illus.
(69) Stow, I.
1927. A 0 YTOLOCICAL STUDY ON POLLEN STERILITY IN SOLANUM TUBEROSUM.
Japan Jour. Bot. 3: [217]-238, illus.
(70) Stuart, W.
1914. disease resistance of potatoes. Vt. Agr. Expt. Sta. Bull. 179,
pp. [145]-183, illus.
(71) ■
1928. THE POTATO; ITS CULTURE, USES, HISTORY', AND CLASSIFICATION.
Ed. 3, rev., 518 pp., illus. Philadelphia and London.
(72) Vesselovskii, I. A.
1933. GROWING POTATOES FROM SEEDS FOR NORTHERN, HIGH AND REMOTE
regions of the u. s. s. r. 20 pp., Leningrad. (Lenin Acad.
Agr. Sci., Inst. Plant Indus.)
(73) Vilmorin, R. de, and Simonet, M.
1927. VARIATIONS DU NOMBRE DBS CHROMOSOMES CHEZ QUELQUES SOL-
anees. Compt. Rend. Acad. Sci. [Paris] 184: 164-166, illus.
(74) and Simonet, M.
1928. RECHERCHES SUR LE NOMBRE DES CHROMOSOMES CHEZ LES SOLANEES.
5th Internatl. Kong. Vererbungswiss., Berlin, 1927, Verhandl.
2: 1520-1536, illus.
438 YEARBOOK, 1937
APPENDIX
Early breeders of potatoes and the varieties originated by them
Breeders Varieties
O. H. Alexander, Charlotte, Vt Charles Downing, Dakota Red, Everett,
Garfield, Green Mountain, Reliance, Tro-
phy, White Mountain.
Martin Bovee, Northville, Mich Bovee, Early Michigan, Pingree.
Albert Breseo, Hubbardton, Vt Early Rose, King of the Earlies, Peerless,
Prolific.
C. W. Brownell, Essex, Vt . Beauty, Best, Centennial, Early Telephone,
Eureka, Superior, Winner, Vermont
Beauty.
Luther Burbank, Lancaster, Mass. Burbank (Burbank's seedling) .
E. S. Carman Carman No. 1, Carman No. 3, Rural New
Yorker No. 2, Sir Walter Raleigh.
E. L. Coy, Hebron, X. Y Early Beauty of Hebron, Late Beauty of
Hebron, Early Puritan, Empire State, Late
Rose, Noroton Beauty, Thorburn,
Vaughan, White Elephant.
Thomas Craine, Port Atkinson, June Eating, Keeper, Potentate.
Wis.
C. E. Goodrich, Utica, N. Y Calico, Cuzeo, Early Goodrich, Garnet
Chili, and several others which were
short lived in the commercial trade.
D. W. HerTron, Utica, N. Y Chicago Market, Climax.
C. G. Pringle, Charlotte, Vt Alpha, Adirondack, Rubicund, Ruby, Snow-
flake.
Arthur Rand, Shelbume, Vt Champion, Delaware, Matchless, Improved
Peachblow, Silver Skin.
Alfred Reese Early Ohio.
G. T. Safford, North Bennington, Gold Coin.
Vt.
F. B. Van Ornam, Lewis, Iowa Extra Early (Burpee's), Great Divide.
Table 1. — Potato varieties available in the United Stales knouti to have characters
of value to breeders
Variety
Source
Superior characters
Chippewa. ..
Golden
Houma ...
24642
Department of
culture.
do
do
do
do..
Agri-
44488
44637
4507S
46208
45349
do
do...
....do
. ..do
46110
46J25
46422
46923...
182-7...
336-7
. ...do
do
do
do
do
. ..do.. .
336-18
336-123
336-144
336-302
3868-8
do.
do
do__
do._
Department of
culture from
man seed.
do._
Agri-
Ucr-
3897-90....
Fertility, resistance to mild mosaic, good shape, high
yield.
Resistance to mild mosaic, good shape, high yield,
early tuber development,
nigh yield, some resistance to scab.
High yield, some drought resistance, good shape, good
cooking quality.
Fertility, resistance to mild mosaic, some earliness.
Immunity to latent mosaic and resistance to mild
mosaic.
Resistance to late blight, high yield.
Fertility, resistance to scab.
Fertility, earliness, good shape.
High yield, good cooking quality.
Resistance to late blight.
High yield.
High yield and cooking quality.
Fertility, yield.
Fertility and earliness.
Fertility and resistance to late blight.
Do.
Do.
High yield and resistance to late blight.
Fertility and resistance to late blight.
Resistance to late blight.
Do.
Do.
POTATOES
439
Table 1 . — Potato varieties available in the United States known to have characters
of value to breeders — Continued
Variety
Source
Superior characters
4-44-12 _
culture.
High yield, quality.
Good tuber type, hardiness.
Kural New Yorker No. 2.
do
do
Do.
Russet Burbank
do
Good quality, resistance to scab.
Charles Downing
do
Good quality and tuber type.
Irish Cobbler
do
Earliness and wide adaptability.
Triumph
do .-.
Earliness.
.-.-do
Do.
Early Ohio
..do
Do.
...do
Warba -
Minnesota
Earliness, yield.
RedWarba
Do.
Arnica. ..
Germany
Resistance to scab.
Hindenburg
do
Do.
Richter Jubel . .
. __ do. .
Fertility, resistance to scab.
Ostragis
do
Resistance to scab.
do
Do.
_.do ..
Ekishirazu . ..
Japan. .. .
Do.
No Blight
Canada
Do.
Paisley's No. 1. . . ...
do
Do.
Paisley's No. 2
do
Do.
Paisley's No. 3
do
Do.
Paisley's No. 4 . _
do
Do.
Imperia ... ..
do._
Resistance to leaf roll.
Triumf...
Netherlands. .. .
Do.
Albion.
do
Do.
Friso
do
Do
West Brabander
do
Do.
Bevelander
do
Do.
...do _
Do.
130.5-24
North Carolina
High yield.
101-91 -
Michigan ..
Good tuber shape, high yield on muck.
155-29
do..
Do.
155-49 .
do
Do.
401-23 -
do
Do.
472-10
do
Do.
472-33
.do... _
Do.
472-53 __
. ..do
Do.
N. D. No. 64
North Dakota
High yield, good shape.
N. D.No. 82
do.
Earliness, good shape.
N. D. No. 8(1
do
Earliness, high yield, and good shape.
N. D.No. 87.
do
F. B. 32-1
High yield, good shape.
11ns).
L.32-1
do.
Russet.
E. 32-7
do.
Earliness, high yield, good shape.
E. 32-8 _
do
High yield, good shape.
252 _
. ...do
Fertility, shallowness of eye.
C. S. 48
Colorado (Greeley)..
Fertility.
C. S.H)
do
Do.
U.S. 98
do
Do.
0. S. 106
do
Resistance to fusarium.
U.S. 125 -
do
Do.
0. S. 133
do
Do.
V. S. 155
do
Do.
Table 2. — Potato lines and progenies known to have superior genetic characters, produced
by the U. S. Department of Agriculture and by the jVeui York {Cornell)
and Minnesota Agricultural Experiment Stations
UMTED STATES DEPARTMENT OF AGR [CULTURE
Cross
no.
774
792
926
1028
295
528
336
618
090
Parentage
Superior characters
S 41956 X Katahdin Resistance to latent and mild mosaics.
S 41956 X S 45075.
Katahdin X S 45075
Katahdin selfed
Russet Rural X S 44537..
Riehter Jubel X S 44537..
No Blight X Katahdin. .
S 45349 X Ekishirazu
S 45349 X Katahdin
Resistance to latent mosaic.
Earliness, resistance to mild mosaic.
Resistance to mild mosaic.
Resistance to common scab.
Do.
Resistance to late blight and mild mosaic.
Resistance to late blight.
Do.
440
YEARBOOK, 1937
Table 2. — Potato lines and progenies knoivn to liave superior genetic characters, produced
by the U. S. Department of Agriculture and by the New York (Cornell)
and Minnesota Agricultural Experiment Stations — Continued
NEW YORK (CORNELL UNIVERSITY) STATION
Line
Superior characters
500 hybrid families
Immunity from late blight.
MINNESOTA STATION
Line
no.
Parentage
Peerless
Cobbler X Peerless
Keeper X Silverskin
(U. S. 14329).
Peerless X Lookout
Mountain.
WarbaX Katahdin... ..
Inbred 41-17 X Inbred
4-9-1.
Snowflake
Burbank X Inbred 60-1. .
Inbred 11-1-25 X Inbred
66-5.
Inbred 49-1 X Inbred
4-9-1.
Inbred 41-1 X Inbred
4-25.
Irish Cobbler
V. S. Seedling 38946
Early Ohio
Katahdin-
Inbred 11-1-25 X Inbred
21-2-2.
Genera-
tions
inbred
(selfed)
Sublines
Inactive
Active
Xu mbcr
i
Xumbcr
13
Number
2
■1
9
11
1S2
3
7
7
90
43
1
0
1
t
150
34
0
29
3
2
2
0
0
2
5
3
10
3
3
30
2
5
40
4
3
23
3
5
130
9
2
0
13
3
0
17
Superior characters
Early maturity, high pollen fertility,
resistance to scab.
Early maturity, vine type.
Early maturity, good tuber shape,
high pollen fertility, free blooming.
Early maturity, high pollen fertility,
short stolons, resistance to scab.
Vine type, tuber quality, resistance
to virus.
Early maturity, good tuber shape,
high pollen fertility, vine type, vigor
and yield, tuber set, free blooming.
Good tuber shape, vigor and yield,
tuber quality.
Good tuber shape, tuber quality.
Early maturity, good tuber "shape,
high pollen fertility, vigor and yield,
free blooming.
Early maturity.
Do.
Early maturity, good tuber shape,
vine type, tuber quality, short
stolons, resistance to virus.
Good tuber shape, high pollen fertility,
vine type, free blooming, resistance
to virus.
Early maturity, vine type, vigor and
yield, tuber set.
Good tuber shape, tuber set, resistance
to virus.
Early maturity, good tuber shape,
high pollen fertility, free blooming.
Table 3. — Potato characters, their genetic behavior, and the investigators
and reference numbers
Character
Genes and interactions
Segregations
Investigators and
i reference numbers
Flower color:
Purple X white
Lilac X white
Blue violet X white.
Light blue (selfed) . .
Light blue X white.
Violet blue (selfed) .
Rod X white.—
Purple X white.
White X white-
Purple dominant to white -
Lilac dominant to white-
Blue violet dominant to
white.
Heterozygous
Multiple factors..
2 complementary genes
D+R for red.
3 complementary genes
D+R+P for purple.
White (selfed)
Light lilac (selfed).
Complementary.
3 blue violet : 1 white.
Monogenic
1 colored: 1 white
Violet-blue, red, reddish
purple, dark and light
blue and white.
In some strains colored
and white,
—.do
9 colored : 7 white.
East (22).
Fruwirth (S3).
MUller (i/).
Heribert-Nilsson (£<).
Do.
Do.
Salaman (68).
Do.
(Salaman) Matsuura
(.59).
Do.
Clark and Stevenson
US).
POTATOES
441
Table 3. — Potato characters, their genetic behavior, and the investigators
and reference numbers — Continued
Character
Tuber color:
White (selfed).
Red (Eelfed)— .
Dark purple X
white.
Dark purple (Fi)
selfed.
Light red X yellow.
Yellow X yellow.
White (&. edmense
selfed).
White (S. edinense)
X white (S. tuber-
osum).
Parti-eolorcd
Do
lied skin color
Red cortical color...
Ked color
Do..
Color, _.
Red (selfed)
Purple (selfed) .
Colored (selfed)—.
Colored X while.
Tuber flesh color:
Flesh color _
Do.... _
Stem color:
Red i'. green
Medium red (selfed)
P'gment
Colored internodes..
Seedling and sprout
color:
Seedling color
Seedling color (blue,
red, green).
Sprouts, blue purple
v. red purple.
Genes and interactions
Homozygous
2 complementary genes
R+D for red.
3 complementary genes
R+D+P for purple.
Heterozygous.
Q and II complementary,
Y inhibitor.
do
3 genes complementary;
B, basic, J), diluting,
M+D= parti-colored
pattern.
Multiple allelomorphie se-
ries for uniformly colored
parti-colored and while.
3 genes complementary,
D+/e=parti-colored,/)+
iJ+^4=uniformly col-
ored.
3 genes complementary,
similar interaction as for
skin color.
Genes complementary,
^4+I)=parti-colored,
yl+D+/;=uniformly
colored; linkage between
A and R.
Genes complementary,.
iJ+S-f X>=red skin color,
i?-j-,S=red eye color.
Genes complementary,
D+J?=red, L+R+P=
purple, and Han incom-
pletely dominant inhibi-
tor.
2 genes complementary-
Single gene, color domi-
nant.
Complementary, C+I=
colored.
C+/+inhibitor JJ=white_
Multiple genes
2 genes, 1 giving yellow in
plant homozygous or
heterozygous, other
homozygous only.
Single gene, red dominant
3 genes complementary, a
fourth gene an inhibitor.
3 genes for color
3 genes complementary.
2 or 3 genes complemen-
tary.
Single gene blue-purple
dominant, same as P
for tuber color.
Segregations
All white
9 red : 7 white..
13 purple : 12 red : 4 while
(Fi).
73 purple : 24 red : 7o white
(Fs).
1 red : 1 yellow (Fi), vari-
ous grades of red, many
having blue or dark-blue
striping, also plants
with colored eyes.
Yellow and 10 percent
blue black, blue, red or
pale red.
13 colored : 40 white
21 colored : 40 white..
27 colored : 37 while, 9 red-
eyed : 7 white-eyed.
9 colored: 7 white.
1 dark purple: 2 light pur-
ple: 1 white.
All white..
1 dark: 2 medium: 1 light.
36 blue:9 red:19 white for
young internodes; 12
blue: 3 red: 1 white for
old internodes.
Seedling color associated
with flower, stem, and
flesh colors.
Investigators and
reference numbers
Salaman (52, 5S).
Do.
Do.
Do.
Heribert-Nilsson (24).
Do.
Miiller Ul).
Do.
Kelly CM).
Collins (20).
Krantz (33, Si).
Do.
Asseyeva (/).
Sirks (04).
Black (4).
Huber (US).
Krantz (SI).
Miiller (41).
Do.
Black (4).
If fiber (15).
East (22).
Salaman (52).
Miiller Ul).
Sirks (*4).
Miiller Ul).
Sirks (64).
Asseyeva (/).
i:ssn04°— :i7 ao + 4-
442
YEARBOOK, 1937
Table 3. — Potato characters, their genetic behavior, and the investigators
and reference numbers — Continued
Character
Habit of growth:
Upright v. prostrate.
Tuber shape:
Hound (selfed)
Oval (medium long)
(selfed).
Long (selfed)
Medium round
(selfed).
Round (soiled)
Tuber shape
Do-
Do.
Depth ofeyo:
Deep (selfed) _
Medium deep
(selfed).
Shallow (selfed)
Deep v. shallow
Time of maturity:
Late X late
Time of maturity..
Inheritance of cropping:
Heavy v. light
Immunity and resist-
ance to potato wart :
Immune (selfed)
Do-
Do
Do
Susceptible X
slightly resistant.
Susceptibility v. re-
sistance.
Do
Do
1{ e s is t a n c e to late
blight:
Resistance v. sus-
ceptibility.
Genes aud interactions
Segregations
Investigators and
reference numbers
At least 3 genes (multiple).
Dependent on more than
1 gene.
Three genes (multiple)
At loast 4 genes (multiple) .
Deep incompletely domi-
nant to shallow.
Shallow eye dominant-
Multiple genes.
2 or more genes, heavy
dominant.
Homozygous.
Single gene immune domi-
nant.
2 genes duplicate
2 genes complementary —
Susceptibility dominant -
Resistance dominant
3 genes (multiple) with
varying values and
cumulative.
At least 2 genes acting in-
dependently.
3 upright: 1 prostrate.
15 upright: 1 prostrate.
63 upright: 1 prostrate.
All round 1
Long: oval: round '
All long I.
Range from round to long.
Not all round
All deep eyed
Deep, medium, shallow.
AH shallow
Wide range of variability
in BY
All immune.
3 immune: 1 susceptible..
15 immune: 1 susceptible.
9 immune: 7 susceptible..
Fi, 29 percent resistant...
Six types of segregation;
no close linkage with
commercial characters.
Salaman and Lesloy
(58).
Salaman (S2).
Do.
Do.
Clark and Stevenson
(18).
Heribert-Nilsson (24).
Black Cf).
Hulier OSS).
Bartosh (*).
Salaman (St, S3, 64).
Do.
Do.
East OK).
Krantz (SI).
Krantz and Hutchins
CM).
Miiller Qt).
Salaman (S6).
Salaman
(60).
Do.
and Lesley
Do.
Do.
Heribert-Nilsson (2.4)
Collins (10).
Orton and Weiss OS) .
Black (S).
Miiller (43).
1 Similar results were obtained by East (%2),
Somatic chromosome
. Chromosome numbers and species
24 chromosomes:
Solarium ajanhuiri Juz.
Buk.
S. aracc-papa Juz
S. boyacense Juz and Buk_.
S. brevidens Phil
S. bukasovii Juz
caldasii Huinb. and Bonl
caldasii glabrescens Dun.
chacoense Bitt
Fruwirth (»), and Krantz (31).
numbers of potato species (2n)
Investigators and reference rios.
and
S.
S.
S.
S. cuencanum Juz. and Buk.
S. fernandezianum Phil
Kovalenko and Sidorov (29), Rybin (49)
Vesselovskii (72).
Rybin (49).
Do.
Do.
Rybin (48, 49).
Dc Vilmorin and Simonet (73, 74).
Longley and Clark (36).
Smith (65), Longley and Clark (36), Rybin
(48), Oppenheimer (44)-
Bukasov (10).
Rybin (49).
POTATOES 443
Somatic chromosome numbers of potato species (2n)- — Continued
Chromosome numbers and species Tncestiaators and reference nos.
S. goniocalyx Juz. and Buk Bukasov (9).
S. jamesiiTorr Smith (63), Do Vilmorin and Simonet
(78, 74), Longloy and Clark (86).
S. kesselbrenneri Juz and Buk_ Bukasov (10).
S. looserii Juz Rybin (49).
8. phureja Juz. and Buk Kovalenko and Sidorov (29), Rybin (49).
S. polyadenium Greonm Longley and Clark (36).
8. rybinii Juz. and Buk Rybin (49).
8. stenotomum Juz. and Buk. __ Rybin (49), Bukasov (10).
8. vavilovii Bukasov (10).
36 chromosomes:
8. cardiophyllum Lind Rybin (49).
8. cardiophyllum f . coyoaca- Longley and Clark (36) .
num Buk.
S. chaucha Juz. and Buk Kovalenko and Sidorov (29), Rybin (49).
8. chocclo Buk and Lechn Bukasov (9).
S. commersonii Dun Longley and Clark (36), Rybin (49).
8. coyoacanum Buk Rybin (49).
8. juzepczukii link Kovalenko and Sidorov (29), Pissarev (46),
Rybin (49).
S. maglia Schlecht Rybin (49).
S. mammilliferum, hiz.aud'Bnk. Do.
S. medians Bitt Rybin (48).
S. riobambense Juz. and Buk__ Bukasov (10).
S. tenuifilamentum Juz. and Rvbin (49).
Buk.
S. vallis-mexici Juz Kovalenko and Sidorov (29), Rybin (49).
48 chromosomes:
S. acaule Bitt Kovalenko and Sidorov (29), Rybin (49).
S. ajuscoeme Buk Do.
S. andigenum Juz. and Buk Rybin (49).
8. aniipoviczii Buk Kovalenko and Sidorov (29), Rybin (49).
8. colombianum trianae Bitt Rybin (48).
S. edinense Berth. (some (Campin), Salaman (55).
forms) .
8. fendleri A. Grav Smith (65), Longlev and Clark (36), Rvbin
(49).
8. leptostigma Juz Rybin (49).
8. tuberosum L De Vilmorin and Simonet (78), Longley
and Clark (36), Pissarev (46), Rybin (49).
60 chromosomes:
8. curtilobum Juz. and Buk Bukasov (9), Kovalenko and Sidorov (29),
Rybin (49), Vessolovskii (72).
8. edinense Berth. (some (Campin) Salaman (55), Rybin (48).
forms).
S. semidemissum Juz Kovalenko and Sidorov (29), Rybin (49).
72 chromosomes:
S. demissum Lind! Smith (65), De Vilmorin and Simonet (74),
Longley and Clark (36), Pissarev (46).
Potato species known to have characters of breeding value,
grouped according to these characters
Characters and species Investigators and reference nos.
Frost resistance:
Solanum acaule Bitt Pissarev (46), Vesselovskii (72), Schick (61).
Solatium ajanhuiri Juz. and Do.
Buk.
8ola,ium andigenum Juz. and Kovalenko (28), Bukasov (9), Vesselovskii
Buk. (72).
444 YEARBOOK, 1937
Potato species known to have characters of breeding value,
grouped according to these characters — Continued
Characters and species Investigators and reference nos.
Frost resistance — Continued.
Solatium bukasovii Juz Bukasov and Lechnovitz (11), Pissarev (49).
Solarium, commersonii Dun Bukasov arid Lechnovitz (11).
Solarium curtilobum Juz. and Bukasov (8), Pissarev (46), Rasumov (47),
Buk. Schick (61), Vesselovskii (72).
Solarium demissum Lindl Bukasov (7), Kovalenko (28), Pissarev (46),
Rasumov (47), Schick (61), Vesselovskii
(72).
Solarium edinense Berth Bukasov (7).
Solarium juzepczukii Buk Bukasov (9), Pissarev (46), Rasumov (47).
Solarium miliaria Buk. and Bukasov and Lechnovitz (1 1).
Lechn.
Solarium semidemissum Juz Bukasov (7), Kovalenko (28), Vesselovskii
(72).
Drought resistance:
Solarium medians Bitt Bukasov (10).
Solatium vavilovii Do.
Late blight resistance:
. Solarium ajuscoense Buk Kovalev (SO).
Solarium antipoviczii Buk Bukasov (10), Kovalev (SO).
Solarium bulbocaslanum Dun.. Bukasov (10).
Solarium demissum Lindl Bukosav (10), Kovalev (30).
Solarium henryi ■ Buk. and Bukasov and Lechnovitz (tl).
Lechn.
Solatium millanii Buk. and Do.
Lechn.
Solatium polyadenium Greenm. Bukasov (10).
Solarium vallis-mexici Juz Kovalev (SO).
Solarium vorrucosum Schlecht. Bukasov (10).
Virus resistance:
Solarium rybinii Juz. and Buk. Do.
Early maturity:
Solanum phureja Juz. and Buk. Bukasov (8).
Solarium rybinii Juz. and Buk_ Do.
Short-day adaptation:
Solanum acaule Bitt Bukasov (9).
Solarium antilobum Pissarev (46) .
Solanum antipoviczii Buk Bukasov (9).
Solanum bulbocaslanum Dun_. Do.
Solarium demissum Lindl Do.
Solanum goniocalyx Juz. and Do.
Buk.
Solanum juzepczukii Buk, Do.
Solanum semidemissum Juz Do.
Solanum squamulosum Mart. Do.
and Gal.
Solanum vallis-mexici Juz Do .
Solanum verrucosum Schlecht.. Do.
Short rest period: •
Solanum boyacense Juz. and Bukasov and Lechnovitz (11).
Buk.
Solanum kesselbrenneri Juz. Do.
and Buk.
Solanum phureja Juz. and Buk_ Do.
Solanum rybinii Juz. and Buk.. Do.
STRAWBERRY
IMPROVEMENT1
GEORGE M. DARROW, Senior Pomolo-
gist, Division of Fruit and Vegetable Crops
and Diseases, Bureau of Plant Industry
X HE strawberry came from North America, and some people think
it is delicious enough to bo a fair exchange for many of the fruits
America has received from other parts of the world. Much of the work
of developing the cultivated varieties has also been done in the United
States; but so universal is the appeal of the strawberry that it is
receiving the devoted attention of plant breeders in such remote lands
as England, the Union of Soviet Socialist Republics (47) 2, and Japan
(83,34,35,86).
The cultivated strawberry is definitely a product of plant breeding
and is relatively young. The commercial development of this fruit
has come principally since the Civil War, and most strawberry varie-
ties now grown have originated within the past 45 years. Seventy
years ago the strawberry was produced almost entirely near a few of
the large cities. Now it is produced commercially in every State in the
United States, as well as in the interior of Alaska. The introduction
of improved varieties has been responsible for the steadily widening
commercial production. When the first productive firm-fruited
variety, Wilson, was introduced about 75 years ago, it became possible
to grow the strawberry as far south as Florida and Louisiana. The
hardy Dunlap, introduced about 35 years ago, made it reasonably safe
to grow strawberries in northern Michigan, northern Maine, and parts
of Canada. Later the origination of suitable high-quality varieties
in Alaska made it possible to raise strawberries commercially even in
that northern region. During the past century hundreds of thousands
of seedlings have been tested, over 2,000 have been named, and a few
score are widely grown; but these few score varieties combine the
many qualities necessary for modern commercial production in every
part of the United States and in every foreign country having a
temperate climate.
The world-wide distribution of the strawberry may be attributed
to three things: (1) The origination of firm varieties like the Wilson,
adapted to widely different conditions; (2) the ability of the straw-
berry to grow from sea level up to elevations as high as 12,000 feet,
in humid and dry regions, in the greenhouses of northern Europe,
1 This report has been made possible by the cooperation of George F. Waldo, of the TJ. S. Department of
Agriculture, at Corvallis, Oreg., and reports for their stations by J. II. Clark, of New Jersey; G. W. Gasser,
of Alaska; A. N. Wilcox, of Minnesota; George L. Slate, of New York; S. M. Zeller, of Oregon; and H. E.
Thomas, of California. W. J. Strong, of Vineland, Ontario, Canada; M. B. Davis, of Ottawa, Canada;
W. S. Eogers, of East Mailing, Kent, England; Laxton Bros., of Bedford, England; P. Sledje, of Njos,
Norway; C. G. Dahl, of AInarp, Sweden; and many others have contributed information that has helped
in the preparation of this report.
s Italic numbers in parentheses refor to Literature Cited, p. 482.
445
446 YEARBOOK, 1937
where the winter day is only 6 or 7 hours long, in Florida and southern
California, where the winter day is 9 or 10 hours long, and in central
Alaska, where the summer day may be 24 hours long (17); and (3)
the high dessert quality and usefulness of the fruit, which matures in
early summer when few fruits are available.
THE STRAWBERRY IS A TRAVELER
The strawbeery was born in North America, traveled to Europe,
and finally returned home. But the strawberry that returned was
very different from the one that went to Europe.
The cultivated strawberry of today is derived from two American
species — the wild meadow strawberry (Fragaria virginiana Duch.) of
eastern North America (figs. 1 and 2), and the beach strawberry
(F. chiloensis (L.) Duch.), found along the Pacific coast from Alaska
to California and along the coast of Chile (figs. 3 and 4). The beach
strawberry is also found on the mountains of the Hawaiian Islands.
The meadow strawberry has thin leaves and bright-red aromatic
berries with deep-set seeds, and it grows freely in many soils and many
THE work of the Department of Agriculture in strawberry breeding
gives an excellent idea of the amount of detail involved in the produc-
tion of improved varieties of plants. In Maryland, the Department
has fruited 86,000 strawberry seedlings, representing artificial
crosses among 150 different varieties. Of these, 1,999 were selected
for further testing, and only 7 have been finally considered worth
naming and introducing. In North Carolina, 54,000 seedlings have
been grown and 1,245 selections have been made for further testing.
In Oregon, the number of seedlings grown was 97,000 and the num-
ber selected for further testing is 1,331. In these few projects, then,
more than a quarter of a million seedlings were involved; feiver than
two out of a hundred were found to be worth further testing; and
perhaps a score or fewer of neiv varieties will finally result. But
of the few varieties already introduced, one is Blakemore, now con-
sidered to be the best preserving strawberry in the United States;
another is Redheart, now more extensively grown than any other
canning variety; and two others are Dorsett and Fairfax, which are
superior in dessert quality to other varieties previously grown. In
addition to this breeding work, 30,000 wild Rocky Mountain straw-
berries were collected in 1936 to be grown at Cheyenne, Wyo., with
the idea of incorporating their superior resistance to cold, dry
winters into cultivated varieties.
STRAWBERRIES
447
locations. In contrast, the beach strawberry has thick leaves and
thill-red berries with less aroma, and the seeds are usually raised
above the surface. It is native only along the beaches. But hybrids
are more vigorous and have wide adaptation.
First Improvement Was Made by American Natives
Before Columbus landed at San Salvador; unknown Indians of Chile,
South America, had selected, from among the wild strawberries that
grew only along the beaches, plants that bore fruit of exceptional size,
Figure 1. — The meadow strawberry of the eastern United States, Fragaria virginiana.
The aroma, the beautiful color, and the wide adaptation of cultivated varieties come
largely from this species.
"commonly as large as a walnut and sometimes the size of a hen's
egg" {48). The fruit was pale red, with firm, meaty, almost white
flesh and a delicate aroma (figs. 3 and 4). More important, however,
the selected plants, or at least one of them, had perfect flowers, while
all the true wild beach strawberries and most of the wild meadow
strawberries of North America have the sexes borne on separate
plants (61). Just where the Indians found such a perfect-flowered
wild plant, or how it came into cultivation, we do not know. An
extensive search by the writer and others on the beaches of California,
Oregon, and Washington has failed to locate a single perfect-flowered
plant. One of the present needs in strawberry breeding is a survey
of the coast of Chile, and particularly of Robinson Crusoe's island,
Juan Fernandez, to locate plants having perfect flowers and to deter-
mine the value of the Chilean wild berries in breeding.
448
YEARBOOK, 1937
This early Chilean variety was taken to Peru in 1557, and it is still
grown in Chile, Peru, Ecuador, and other South American countries.
The second important character in the story of the modern straw-
berry was a French officer, M. Frezier, who returned to Europe from
Chile in 1714. He arrived at Marseilles, after a 6-month voyage,
with five live plants of the Chilean variety (48). Plants of the
meadow strawberry of eastern North America had already been taken
to Eiirope, and from crosses of these two forms the modern strawberry
was developed in Europe.
A third great character in the story was also a Frenchman, named
Duchesne. In 1760, when only 19 years of age, he published a book
of over 400 pages on the strawberry (22). He described the wild
species, noted that
some varieties had
both pistils and sta-
mens in their flowers
and bore fruit, that
others had only pistils
and bore no fruit un-
less they grew near
varieties that had sta-
mens, and that still
others had stamens
and pistils but were
sterile. Duchesne was
probably the first to
make actual crosses of
strawberries.
A fourth character
was an Englishman,
Thomas Andrew
Knight, who originat-
ed the Downton and
later, about 1820, the
Elton Pine, which is
still grown in Europe (29). He made many crosses and proved that
systematic breeding would result in improved varieties. He was
really the world's first systematic fruit breeder. Best of all, he was
a scientist who combined his scientific studies with practical breeding
to secure better varieties. He has been followed by many strawberry
breeders in England and on the Continent.
A fifth great character in strawberry history was Nicholas Long-
worth, a prominent horticulturist of Cincinnati, Ohio, and great-
§randfather of Nicholas Longworth, the late Speaker of the United
tates House of Representatives (11, 12). In spite of the work of
Duchesne and a few others, few people in the United States knew
there were different sex types in the strawberry. Longworth redis-
covered these differences some time before 1834. He and his asso-
ciates are said to have examined millions of strawberry flowers and
classified plants into four groups — (1) pistillate, (2) hermaphrodite or
perfect, (3) two rather rare classes having staminate flowers, and
(4) a class having both pistillate and hermaphrodite flowers on the
Figure 2. — A pistillate-flowered seedling of a cross of the
meadow strawberry (Fragaria virginiana) X ' Dunlup.
Note the deep-set seeds.
STRAIT-BERRIES
449
Figure 3. — The Chilean strawberry (I'rugaria chitoensis) as grown at Ambato,
Ecuador, at an elevation of about 10,000 feet, where the rainfall is probably
not over 15 inches a year. This is thought to be the same variety of straw-
berry that Frezier took to Europe in 1712 and that was grown by the Indians
in Chile when Columbus discovered America.
130
YEARBOOK, 1937
same plant. Longworth found that not over one-third of the flowers
of the hermaphrodite varieties ever set fruit, while all, or usually all,
of the flowers of pistillate varieties set fruit. Longworth 's work
eliminated one great cause of failure in commercial berry production
and made it possible to raise strawberries much more widely than
before. Though the difference between pistillate and so-called
perfect-flowered varieties has been common knowledge since the time
of Longworth, much of his work on the degree of sterility of the
Figure 4. — The same variety of Fragaria chitoensis as in figure 3 but grown in a green-
house near Washington, D. C, showing differences in shape and position of calyx
(cap or hull). These berries were soft, while those shown in figure 3, grown in a cool,
dry climate at a high elevation, are the firmest of any strawberries known in the world.
perfect-flowered varieties was lost sight of until rather recently, when
it was rediscovered by Valleau (60) of Minnesota.
Origin of American Varieties
The varieties originated in Europe were soon introduced into the
United States, and many of them were grown extensively in this
country, especially in the years before 1850. Commercial strawberry
growing near the largest cities had begun in the United States about
1800, with such old varieties as Large Early Scarlet, Early Hudson,
Hudson's Bay, Crimson Cone, Red Wood, and later the Hovey.
Since the time of Nicholas Longworth the outstanding development
has been the introduction of a succession of new varieties with qualities
that have made possible the extension of the territory where straw-
berries could be grown (28). Among the most important of these
have been the Wilson, originated in 1851; Crescent in 1870; Sharpless
STRAWBERRIES 451
in 1872; Aroma in 1889; Dunlap and Marshall in 1890; Thompson in
1894; Klondike (10) about 1896; Missionary about 1900; Ettersburg
121 in 1907 ; Howard 17 in 1909 ; Progressive in 1908 ; Blakemore, Dor-
sett, and Fairfax in 1923; and Catskill in 1924 (18, 29).
In England, Myatt introduced the British Queen in 1840, and
Bradley originated the Sir Joseph Paxton in 1862 and introduced the
Dr. Hogg in 1866. The Jucunda originated with Salter before 1860.
A large number of the other important English varieties were
originated by Thomas Laxton and by his sons, the firm of Laxton
Bros. With the encouragement of Darwin, Thomas Laxton began
his strawberry breeding about 1865. His first variety was the Noble,
introduced in 1884 and still grown extensively, especially in Germany
and the Netherlands. In 1888 the King of the Earlies was intro-
duced, and in 1892 the Royal Sovereign, a cross of Noble and King
of the Earlies. Though British Queen and Dr. Hogg are the finest in
quality in England, Royal Sovereign has high quality and is probably
the most widely grown variety in northern Europe. Latest of All
was introduced by Laxton Bros, in 1894, and Givons Prolific, raised
by William Peters of Givons Gardens, was introduced in 1901.
Bedford Champion was introduced by Laxton Bros, in 1904 and
The Duke in 1919.
In France (38, 46) Pelevain introduced Princess Royale in 1844,
and it was said to have been the leading French variety for over 50
years. About 1856 the Vicomtesse H. de Thury, raised in 1845 by
M. Jamin, was introduced; Marguerite was originated in 1859 by M.
Lebreton; and in 1871 the Dr. Morere, raised by M. Berger, was
introduced. Dr. Morere has been grown as widely in France as the
Royal Sovereign in England.
In the Netherlands, Mme. Kooi was raised by G. Kooi before 1920
and introduced by R. Hendrikson, who also introduced the Mme.
Lefebre.
In Germany, Late Leopold, raised by L. Lierke, was introduced
in 1904. Deutsch Evern, a cross of Sieger X Noble, was raised in
1902.
STRAWBERRY VARIETIES OF THE WORLD3
United States
A great many varieties have been grown in the United States, but
at present only about 30 are important, 20 of them in about the order
shown in table 1.
Besides the 20 listed, 11 other varieties make up about 4 percent
of the total acreage (18). These varieties, with the same abbrevia-
tions for origin as in the table, are Catskill (Br), Clark (Br), Oelrich
(Ulrich) (Ch), Ettersburg 121 (Br), Corvallis (Br), Glen Mary (Ch),
Ridgely (Ch), Sample (Ch), Clermont (Br), Fairfax (Br), and Nar-
cissa (Br). Though there are many other varieties in the trade,
they are grown to a very limited extent.
Twenty-two of the thirty-one varieties were originated as the
result of breeding, and they constitute over 75 percent of the acre-
age (18, 32). For the most part, each of the important varieties has
3 The strawberry species are described and listed in the appendix.
452
YEARBOOK, 1937
made its way rather quickly into a prominent position. Growers
generally are interested in testing new sorts and are ready to change
to any promising new variety. For example, the Howard 17 was
introduced under that name in 1918, and 10 years later it was the
principal variety north of the Ohio and Potomac Eivers. The
Dorsett, introduced in 1933, has already become well known on the
larger markets of the Eastern States.
Table 1. — Important strawberry varieties grown in the United States
Bank
Variety
Total
acreage
Origin i
Approximate
date
introduced (i)
or
originated (o)
1
Percent
30.0
IB. 0
10.0
8.0
7.0
7.0
3.5
2.0
2.0
2.0
1.0
1.0
1.0
1.0
1.0
1.0
.5
.5
.5
.5
4.0
1890 (o).
1918 (i).
1839(o).
1923 (o).
1900 (o).
1890(0).
1890 (o).
1003 (o).
1899 (i).
1923 (o).
1909(o).
1905 (o).
1902 (i).
1885 (o).
2
Howard 17 (Premier)
Br-Pri
;s
Br-Pri
4
5
Blakemore .. _ ... __
Br-Pub
Ch
Ch
Br-Pri
Ch
Br-Pri
Br-Pub
7
8
Marshall ..
Dunlap -.- . -. . ... -.
9
10
Dorsett.. __ __
Aberdeen. _ .
Lupton. .
Ileflin
Gandy _. _ .. _.
11
12
13
Br-Pri .
Br-Pri_ ...
14
15
Br
Br-Pri... .
16
17
Nick Ohmer . ...
Eedheart _ _
Belt (Wm. Belt)
Mastodon.. ..
Parsons (Pocoraoke)
Other varieties _ .... _.
Br-Pri
Br-Pri
1898 (i).
1931 (o)
18
Br-Pri
1888 (o).
1917(0).
1890 (o).
19
Br-Pri
20
Ch
' Br=breeding; Pri=private agency; Pub=public agency; Ch=chance seedling.
The varieties now used probably represent better adaptation to
conditions in the regions where they are grown than former sorts.
Varieties sueh as Missionary, Klondike, Dunlap, and Heflin are more
like the wild meadow strawberry of eastern North America than like
the beach strawberry. Through the hundred years of evolution in
the cultivated strawberry the varieties have been tending toward the
native eastern wild strawberry. This has occurred because (1) most
varieties have originated in the East; (2) seedlings with more of the
characteristics of native wild strawberry have naturally succeeded
best and have been selected by breeders; and (3) many varieties, such
as Missionary, were found in the wild as chance seedlings. The latter
may have originated either from seed of cultivated varieties or as the
result of bees carrying pollen of cultivated sorts to the native straw-
berry. In some regions along the Atlantic coast most of the straw-
berries found growing wild are now in part derived from cultivated
sorts. Natural crossing of cultivated with the beach and the Rocky
Mountain strawberries has already started in the Western States, and
many natural crosses have been found there.
Fairfax, of the eastern varieties, and Ettersburg 80 and 121, of the
western varieties, are the nearest to an intermediate between the
eastern meadow strawberry and the beach strawberry. Dorsett (fig.
STRAWBERRIES
453
5), Howard 17, Chesapeake, and Marshall are thinner leaved and
thus somewhat closer to the Missionary, Klondike, and Dunlap group.
The success of Etter (8) and Georgeson (30) whose work will be dis-
cussed later, in using selections of the beach strawberry has revived
interest in this species. It is now being used extensively, particularly
in the California and the United States Department of Agriculture
breeding work, to increase vigor and to obtain resistance to root rots.
Hybrids of cultivated varieties with Fragaria chiloensis, the beach
strawberry, have much greater vigor than most variety crosses. It
Figure 5. — The Dorsett strawberry, a variety of very high flavor, resulting from a cross
of Howard 17, which is the principal variety of the northeastern United States, and
Royal Sovereign, long the standard of excellence in northern Europe.
appears that through the scores of years since the strawberry came
back from Europe some inbreeding has occurred that has lessened the
vigor of the cultivated strawberry.
Important Varieties in Foreign Countries
The strawberries of Canada are similar to those of the United
States, the varieties being the same in most instances. In eastern
Canada, Dunlap, Parsons, Howard 17, and Glen Mary are the chief
sorts. In British Columbia, British Sovereign, Magoon, Marshall,
and Sir Joseph Paxton are raised in the milder coast climate, and
Dunlap, Glen Mary, and Parsons (Gibson) in the interior.
Because wild parental types of the cultivated strawberry are not
native to Europe, Asia, Africa, or Australasia, varieties of these coun-
tries are all, or nearly all, the result of breeding. The varieties so
454 YEARBOOK, 1937
developed differ from one another more than do American sorts.
The principal varieties grown in each country are as follows:
England. — Royal Sovereign, Mme. Lefebre, Late Leopold, Oberschlesien, and
Huxley (probablv Ettersburg 80). The Duke, Sir Joseph Paxton, Bedford Cham-
pion, and Mme. iKooi are being grown somewhat, and Western Queen and Pillnitz
are being tested.
Scotland. — Scarlet Queen, John Ruskin, Royal Sovereign, MacMahon, and
The Duke.
Germany. — Deutsch Evern and Noble for early, Sieger, Oberschlesien, and
Roter Elefant for midseason, and Jucunda and Leopold for late. Vierlanden is
raised near Hamburg.
Netherlands. — Jucunda, Deutsch Evern, and Noble, with some Scarlet and
Oberschlesien.
France. — Minerve, Souveraine, Moutot, V. H. de Thury, Dr. Morere, Paxton,
Tomate, Marguerite, Leopold, and others.
Norway. — Deutsch Evern, Abundance, and Bedford Champion.
Neio Zealand. — Marguerite, Melba, Ettersburg (80 or 121?), Captain Cook,
Noble, Helenslea, Surprise, and Royal Sovereign.
Victoria. — Melba and Wilson's Pride.
Tasmania. — Ettersburg (80 or 121?), Royal Sovereign, Melba, and Abundance.
STRAWBERRIES FROM SEED
The varieties of cultivated strawberries of the United States do not
come true from seed. If 1,000 seeds of Marshall or Klondike or
Howard 17 are planted, no 2 seedlings will be exactly alike. Some
plants will be weak, some strong; some will make few runners, some
many; some will have large fruit, some small; some will be productive,
some unproductive. Out of the thousand, few if any will be as good
as the parent. Because they do not come true from seed, and because
they are so easily propagated by runners that root at the tip to form
a new plant, all "American varieties are propagated in this way, never
by seed.
In Europe there are a few cultivated varieties called alpines or ever-
bearing wood strawberries, some of which are often and others of
which are always raised from seed. They produce much smaller fruit
than do our cultivated varieties and are closely related to the wood
strawberries of North America. Thus, the Bush White is an alpine
variety that makes no runners, has small, white fruit, and, because it
makes no runners, is always raised from seed. The Belle de Meaux
is an alpine that produces runners, has red fruit, and may be raised
from seed or propagated by runners. Such varieties have been
selected, as have vegetables and other seed-propagated plants, until
they come approximately true from seed. Seed varieties of alpines
are relatively easy to establish as compared with seed varieties of the
common cultivated strawberry. However, these alpine varieties are
rarely grown in the United States.
Though it is extremely unlikely that any one of 1,000 seedlings of
Marshall, Klondike, or Howard 17 will be better than its parent,
breeders have learned that if Marshall is crossed with some other
variety and 1,000 seedlings are raised, the progeny will bo far more
vigorous and productive than seedlings of Marshall that are not the
result of crossing. Thus, from a cross between Marshall and Howard
17, Slate, at the New York (State) Agricultural Experiment Station,
raised 1,132 seedlings and saved over 150 as especially promising (55).
S TRA \V BERRIES 455
From these he selected a seedling that he named Catskill, which
combines many of the good qualities of both parents. It is now
widely grown.
FLOWER TYPES IN STRAWBERRIES
Cultivated strawberries produce two general types of flowers —
pistillate, and perfect or hermaphrodite (11, 18). Pistillate flowers
contain pistils, the female parts, but no stamens, while perfect or
hermaphrodite flowers contain both pistils and stamens, the male
parts. The other two types of plants, staminate and that with both
pistillate and perfect flowers on the same plants, are rare. Pollen is
Fiffire 6. — A strawberry flower showing the pistils in the center
surrounded by stamens. The anthers at the ends of the stamens
are cracking open around the edges and shedding pollen.
carried by bees and other insects, but it is also thrown out of the
stamens as the anthers crack open (fig. 6), or it is jarred out and blown
by the wind and falls on the pistils. A variety having perfect or
hermaphrodite flowers can produce fruit when planted by itself, but
one with pistillate flowers cannot set fruit unless perfect-flowered
plants are nearby to furnish pollen through the agency of bees or other
insects. Because of this, varieties having pistillate flowers are not
generally so desirable as those having perfect flowers, and few of them
are grown now. However, some of these pistillate varieties are very
productive. Pistillate varieties are also injured less by the strawberry
bud weevil than perfect sorts, since this insect feeds on pollen ; and in
regions where it is serious, pistillate sorts are still grown. When the
plants are in flower it is very easy to tell a pistillate from a perfect-
flowered variety, as illustrated in figure 7.
456 YEARBOOK, 193 7
Partial Sterility of Perfect-Flowered Varieties
Though the flowers of pistillate varieties nearly always set fruit
when pollinated, those of perfect-flowered varieties rarely all set fruit.
The flower may appear to be normal, but the pistils may be sterile.
Under some conditions not 1 in 50 of the flowers of certain varieties
sets fruit. Studies by Valleau (60) have shown that only the pistillate
plants of the wild meadow, beach, and mountain strawberries set fruit.
Perfect-flowered plants in the wild are in reality males, even though the
pistils usually appear normal. Occasionally the first flower to open
on a wild perfect-flowered plant may set a berry, and very, very rarely
Figure 7. — A perfect or hermaphrodite strawberry flower (A) having both pistils and
stamens, and a pistillate flower (I!) having pistils but no stamens. Pistillate varieties
will not produce fruit unless they are grown near plants having perfect or pollen-
producing blossoms so that bees can carry the pollen to the pistillate flowers.
most of the perfect flowers on a plant of the wild meadow strawberry
may set fruit.
The first flowers to open on a cluster of a perfect-flowered variety
are more likely to set fruit than the later ones, and the last ones to
open are most often sterile. On the average about one-third of the
blossoms of cultivated perfect-flowered varieties are sterile. The
clusters produced by the main crown of a plant have fewer sterile
flowers than the later-formed clusters of branch crowns. Through
scores of years, by breeding and selection, perfect-flowered varieties
have now been obtained that set nearly all their flowers. In fact,
under favorable conditions all the flowers of the Rockhill everbearing
seem to set.
At its base the pistil contains a minute egg cell ready for fertiliza-
tion when the flower opens. After pollen is placed on the end of the
pistil, one or many of the pollen grains start to grow a tube down the
center of the pistil. The pollen absorbs food from the tissues of the
pistil, and finally one pollen tube reaches the egg cell. The sperm
nucleus, a minute globular mass in the pollen grain, passes down the
pollen tube, enters the egg cell, and unites with the egg nucleus. When
the nuclei of the pollen and egg unite they form a single cell that is the
germ of a new plant. By successive divisions of this original cell, the
STRAWBERRIES 457
embryo plant, contained in the seed that we see on the outside of the
strawberry, is finally formed. Within a few hours after the pollen and
egg nuclei unite, the ends of the pistils dry up. If no pollen reaches
the ends of the pistils they will not dry up nearly so quickly. After
the embryo has started to grow, the .tissue around the seed starts
to develop into what we call the strawberry. If any pistil is not
pollinated, then the tissue around the base of that pistil does
not develop. When the pistils on one side or part of a flower have
not been pollinated or have been damaged by frost, the result is a
misshapen berry.
TECHNIQUE OF BREEDING STRAWBERRIES (19, 20)
Crossing of strawberries may be done in the field under cages of wire
screen or cloth or under sun traps (fig. 8, A). Malting large numbers
of crosses in the field is very laborious and must be done within a short
time. Flowers may be killed by unseasonable late frosts, so that the
work has to be repeated and time is lost. For these reasons, if facili-
ties are available the crossing should be done in greenhouses, either
heated or unhoated (fig. 8, B).
The other advantages of using an unheated greenhouse are that
(1) the flowers open about a month earlier than in the field; (2)
it is possible to stand erect or sit while doing the crossing; (3)
the pots can be carried to different parts of the greenhouse to
save time; (4) insects usually do not interfere, so that the plants
do not need to be covered ; (5) the stamens do not open before the
petals unfold, which makes it possible to emasculate and pollinate
at the same time, while many stamens shed pollen before the flowers
open out of doors; and (6) many perfect-flowered varieties produce
primary, secondary, and even tertiary flowers having no pollen-
bearing stamens, so that emasculation of such flowers is unnecessary,
yet out of doors most flowers of the same varieties produce good
stamens. Plants may be potted any time during the fall or winter
for bringing into such an unheated greenhouse.
Pollination
In emasculating, the thumbnail is generally used to cut away the
stamens, corolla, and calyx at one operation (fig. 9, .4). If this is done
with ordinary care, no injury to the pistils follows. Often the calyx
and corolla are removed to identify crossed flowers even though emas-
culation is not necessary. The primary and secondary flowers, the
first and second to open, contain far more pistils than the flowers
opening later in a cluster. Berries developing from the primary
and secondary flowers can set far more seed than the later berries,
hence every effort is made to pollinate the earliest flowers on each
cluster.
In crossing, the flowers having unopened pollen-bearing stamens
are picked and allowed to wilt until the anthers crack open to let the
pollen out. The flowers are used directly on those to be crossed, being
held so that the stamens touch the pistils. The flower is then twirled
by its stem so as to cover all the ends of the pistils with pollen (fig.
9, B). A flower with abundant pollen may be used to pollinate four
138004°— 37 30
458
YEARBOOK, 193 7
Figure 8. — .1, Types of coverings formerly used to keep insects away from flowers that
were being crossed in the field: a, A wire screen cage; b, a glass sun trap. In recent
years the work has been done far more quickly and safely in cold greenhouses or prop-
agating houses, as shown in B. B, Interior of a cold greenhouse at the breeding season.
Note that the benches are of solid earth and that the center walk is below the ground
level. The house is of the simplest construction, being made of coldframe sash. The
potted plants of the different varieties to be used in breeding have started spring
growth, and most of the crossing can be done before the flowers start on plants
out of doors.
to six flowers or even more. Some breeders collect pollen and then
use small brushes to apply it.
After being pollinated, the flower, flower cluster, or plant is marked
to indicate the cross (fig. 10) and then bagged or protected in some
STRAWBERRIES
459
Figure '). Crossing the strawberry: A, Flowers being prepared for crossing. The
petals, sepals, and stamens are removed by cutting them off with the thumbnail.
B, Flowers being pollinated. The flower of the variety to be used as a male parent is
being pressed against the pistils and the flower twirled between the fingers to brush the
pollen onto the pistils.
460
YEARBOOK, 1937
way from insects if necessary (fig. 8, A). The Derries are picked as
soon as they are fully mature. The fresh berries may be mashed in
dry sand to separate the seed, and the mixture of seed, pulp, and
sand is sowed in flats and pots at once. They are then covered with
about one-eighth of an
inch of sand, and at
no time is the seed al-
lowed to become dry.
With temper a t u r e s
from 60° to 80° F., the
seed germinates in a
few days. With very
high temperature the
seed may become dor-
mant and stay dor-
mant until after a pe-
riod of cold weather.
Soil to which commer-
cial fertilizer has been
added should not be
used, for it may pre-
vent germination.
Handling
the Seedlings
^Yhen they reach a
size convenient for
handling (fig. 11), the
seedlings are pricked
either into flats 2 inch-
es apart or into thumb
pots. As soon as they
are large enough (2 to
4 weeks) they are set
in the field. If set in
the field in Maryland
by July 1 they should
produce a good crop
the next spring. The
plants may be set 4
to 5 feet apart and
allowed to make a
small mat of runner
plants, or 12 to 18 inches apart in the row and all runners kept off.
Selection of Seedlings
At the beginning of the ripening season, all plants that would not
be desirable commercially, including dwarfs and those subject to leaf
or root diseases, may be cut out. Further selection when fruit
characters are judged will then be easier. The number of selections
made for fuUire testing varies greatly but is rarely over 10 percent
and is usually less than 2 percent of the plants fruited (fig. 12). The
Figure 10. — A pistillate variety used in breeding. The
petals and sepals were removed from the flowers when
they were pollinated in order to identify them. The
label indicates that all 24 flowers were pollinated with
U. S. D. A. selection no. 632 (Redheart).
STRAWBERRIES 461
selections are then propagated and a second test on a larger scale,
either a 25- or a 50-foot row, is made in comparison with standard
varieties. After the second test some selections may be tested further
for some special quality such as suitability for preserving, canning, or
shipping, or for behavior in different regions of the country.
STRAWBERRY BREEDING IN THE
UNITED STATES
Objectives
The fine dessert quality and the extensive cultivation of the straw-
berry today are B tribute to the ability and industry of breeders of
>!•- S-
r t t
•
I i pure 11. — Strawberry plants grown from seed. The five seedlings at the left are the
proper size for repotting; the one at the right is larger than the usual size.
the past century and a half. Further improvement may consist
largely in obtaining varieties with (1) greater resistance to leaf, crown,
and root diseases, to the virus diseases, and possibly to insects and
nemas (eelworms) ; (2) greater resistance to high and low temperatures
and to drought; (3) better adaptation to long and short days (17);
(4) better dessert quality under adverse weather conditions; (5)
increased firmness and toughness of skin ; and (6) better adaptation to
specific uses such as deep red, firm, tart varieties for canning; varieties
holding their shape, texture, flavor, and color after freezing; light
red but red to the center, tart, firm ones for preserving (15); varieties
with aroma suitable for flavoring, etc. Such improvements would
lessen the risks now faced in growing strawberries. Varieties most
desirable for freezing for the small-package trade have been found too
subject to diseases or not productive enough to become commercial
sorts. Southern varieties have been highly acid and without much
aroma in cold and unfavorable weather, yet there are varieties that
have high flavor under such conditions.
462
YEARBOOK, 193 7
Methods of Breeding
So far, improvement has come through direct crossing of varieties
and species and backcrossing to the parents. Crossing and the raising
of large numbers of seedlings is relatively easy and has been a rapid
and effective method of breeding. Backcrossing a seedling to one of
its parents has long been used by strawberry breeders as a regular
practice. There is much that can probably still by done by these
methods. However, with new problems, new methods, and now
Figure 12. — After "Judgment Day" in the strawberry field. This photograph shows
what is left after selection has been completed. The seedlings that have been found
wanting have been destroyed, and of the thousands of plants originally in the field
only a few remain.
facilities, plant-breeding practices may change. The sporting of
Blakemore, Howard 17, and other varieties to yellow plants may make
new methods useful.4 Sporting to yellow leaves seems to be due to
the appearance of recessive characters. Because this yellow plant is
worthless, a method needs to be devised for eliminating its inheritance
from breeding stock and from varieties to be introduced.
The use of selfing to obtain relatively pure lines has not been
satisfactorily explored, though some selfing has been done by several
breeders. When selfing has proceeded for two or three generations,
the plants are not vigorous and may be easily lost. Only under very
favorable conditions can they be kept alive. For tliis reason, little
information on this method is yet available. Yet immunity from or
lugh resistance to leaf spot or other diseases may be due to recessive
4 Darrow, G. M. notes on variegated leaf troubles oe strawberries.
Plant Disease Reptr. J8: 26-29. 1934.
V. S. Bur. Plant Indus.
STRAWBERRIES 463
genes and appear only after inbreeding. Yellow leaf seems to be a
recessive character that might be eliminated by selfing and by selecting
selfed lines that do not carry it.
Private Breeders
Of the private breeders who produced varieties previously listed,
the following are still living: A. F. Etter, Ettersburg, Calif., originator
of Ettersburg 121 and other varieties; E. C. Howard, Belchertown,
Mass., who was associated with his father in the origination of Howard
17 and Howard Supreme varieties; Harlow Rockhill, Conrad, Iowa,
originator of Rockhill and Progressive, everbearing varieties; and
Jeff Beaver & Son, Eau Claire, Wis., originators of Beaver. Other
private breeders are Horace Wray, White Salmon, Wash., originator
of Wray Red; and W. Kosuga, Sandy, Utah, originator of Berri
Supreme.
These breeders made crosses and selected the seedlings that seemed
to come nearest their ideal. Some of them have kept detailed records
of their work, as the following parentage of Howard 17 shows:
Howard 17{gfiS - 1 - Howard®^ no. 4 of Haw^{gfi^
The Howards tried to recombine in one variety the desirable
qualities in several. Slate (55) has stated that Howard 17 is the
outstanding parent used at the New York station. It has also been
an exceptional parent in the breeding work of the United States
Department of Agriculture.
A. F. Etter (fig. 13) has collected and used selected wild straw-
berries in his breeding work, which began about 1885 (8). His most
valuable contribution has been this use of selections from the wild.
Most of the 50 or more varieties introduced by him are derived from
selections of the beach strawberry, Fragaria chiloensis, crossed with
cultivated varieties. Qualities that he has bred into strawberry
varieties through use of selections of the beach strawberry are being
extensively used by other breeders. Thus, Redheart is a cross of
Portia X Euresko, the latter being one of Etter's varieties. South-
land resulted from a cross of Howard 17 X Ettersburg 80, while
Corvallis is a cross of Marshall X Ettersburg 121. Many selections
at experiment stations resulting from breeding work and under test
at present have as one parent one of the Etter varieties or a variety
or selection derived in part from his varieties.
Harlow Rockhill began his work with the everbearing strawberries
in 1895 and has used both American and European sorts in his breed-
ing. Progressive was his first production to be widely grown. His
later variety, Rockhill (Wayzata), is resistant to cold and to leaf dis-
eases and is one of the highest in dessert quality in the United States
^ b' '* Federal Strawberry-Breeding Work
The Federal strawberry-breeding work (19, 20) has been carried on
in Maryland since 1920. The work was extended in 1928 to include
cooperative work at the North Carolina Coastal Plain Branch Station
at Willard and the Oregon Agricultural Experiment Station at Cor-
vallis.
464
YEARBOOK, 1937
Over 86,000 seedlings, representing hundreds of crosses, have been
fruited at Glenn Dale, Md., and at United States Horticultural Station,
National Agricultural Research Center, Beltsville, Md. In all, over
150 varieties and 20 selections of species have been used in this breed-
ing work. Selections to the number of 1,999 have been made, 7 var-
ieties have been named and introduced, while 342 selections are still
unnamed and are being held for further testing or for breeding.
The first work at Willard consisted of tests of selections from the
Glenn Dale station. Beginning in 1929, small seedlings raised in Mary-
land were taken to Willard and fruited there. Since the beginning
about 54,000 seedlings have been grown at Willard and 1,245 selections
have been made. No selections
have been named, though several
are being extensively tested and
propagated. The crosses have
been made especially to obtain
firmer, higher flavored shipping
varieties for the South.
At the Oregon station the first
work also consisted of tests of
selections made in Maryland.
However, crossing was immedi-
ately begun, and to date some
97,000 seedlings have been fruit-
ed and 1,331 selections made.
No selections have yet been
named, though many are being
extensively tested. The crosses
made have been largely to ob-
tain better preserving, freezing,
canning, and shipping berries.
At the United States Horticul-
tural Field Station, Cheyenne,
Wyo., the first selections of the
wild Rocky Mountain straw-
berry, Fragaria cuneifolia Nutt.,
were made in 1935. Though small fruited, they proved much hardier
than cultivated varieties, and in 1936 over 30,000 plants were collected,
chiefly from the States of Wyoming, Colorado, Utah, Montana, and
South Dakota. Selections of these are to be used by Powers and
Hildreth in crossing to produce varieties more resistant to cold, dry
winters.
Extensive tests of many of the selections at Willard, N. C, have
been made in Maryland and at Corvallis, Oreg., to find some espe-
cially adapted to freezing in small packages with sugar or sirup.
Similar tests have been made of the preserving and canning qualities
of many varieties. As a result of this work, the Blakemore was
selected early in the breeding work for its superior qualities for the
making of preserves (15). It is considered the best of all varieties for
this purpose in the United States. The Redheart was selected for its
canning qualities and is now raised more extensively than any other
canning variety. Breeding for firmness and adaptation to short day
Figure 13. — A. F. Etler, Ettersburg, Calif.,
pioneer in the use of native western straw-
berries, plums, apples, and gooseberries.
Not only have his varieties been widely
grown, but other breeders have used them
extensively in their breeding work.
STRAWBRERIES
465
length requirements at the Willard station have been other objectives.
Some of the crosses that have some of these desirable qualities are
listed in the appendix under Sources of Superior Qualities in Straw-
berries.
Studies on the sterility of flowers {12), types of flower clusters {13),
number and length of runners, stomata of the leaves {14), transpira-
tion from the leaves, fruit-bud development {(!), spacing of plants, and
leaf area in the late fall have shown just what plant characteristics
are most desirable and why. Tims, the fertility of all the flowers of
Kockhill, the low-branching fruit clusters and early fruit-bud initiation
Figure II. — The Kockhill everbearing variely (I) contrasted with a variety of the
Alpine everbearing (Fragaria vetca temperfloretu) (B). Note the much smaller fruit
of l he latter.
of Howard 17, the long, large runner and natural spacing of plants of
Fairfax, the type of stomata of Blakemore {14), and the extensive leaf
area of Dorsett when spaced — these have been found to be desirable
characteristics under some conditions and useful in breeding. In fact,
an intimate and extensive knowledge of such characteristics in vari-
eties is of great importance in selecting varieties for breeding and in
making selections from seedling fields.
Strawberry Hreeding at State Experiment Stations
Extensive strawberry breeding is a part of the work at many State
experiment stations. A list of the workers at these stations and the
locations of their work is given in the appendix.
A relatively small part of the total strawberry acreage of the
country — about 10 percent — consists of varieties originated by public
466 YEARBOOK, 1937
agencies. However, the acreage of Catskill, Dorsett, Fairfax, and
other new introductions is increasing rapidly, and these varieties are
becoming important commercial sorts. Strawberry breeding has been
started only recently at many experiment stations as the need for
better varieties has become^ apparent. Results from much of this
work are not yet, of course, in the trade.
Alaska
Strawberry breeding was begun in Alaska (30) in 1905, the first
crosses being made between cultivated varieties and selections of the
beach strawberry, Fragaria chiloensis. Later, selections of the hardy
interior wild strawberry, F. cuneifolia (F. platypetala Rydb.), as well
as numbered seedlings, were also used in crossing. Named varieties
from the States do not succeed in the climate of Alaska, and crosses
were made to obtain varieties with the size and productiveness of the
cultivated varieties and the hardiness of the native wild strawberries.
Some of the resulting hybrids were found to be hardy at Fairbanks, in
the interior of Alaska, where extremely low temperatures occur in
winter and where there is continuous daylight for about 2 months in
summer. Up to 1922 some 11,600 seedlings had been raised. As a
result of this breeding work strawberries are now commonly grown in
Alaska. Since about 1922, varieties originating at the experiment
station at Sitka have supplied the markets both on the coast and in
the interior, even above the Arctic Circle.
Minnesota
Strawberry breeding in Minnesota was begun in 1908 and has con-
tinued to the present. The earlier work consisted of crosses between
commercial varieties to obtain hardier sorts. Between 75,000 and
100,000 seedlings were raised from 1909 to 1924. Seven varieties
were named and introduced as the result of this work — Duluth and
Deephaven as everbearing sorts, and Minnesota, Minnehaha, Chaska,
Easypicker, and Nokomis as early summer sorts. The principal
varieties used as parents were Abington, Autumn, Beder Wood,
Brandywine, Clyde, Cresceut(?), Duluth, Dunlap, Easypicker,
Enhance, Golden Gate, Jessie, Margaret, Pan American, Prolific, and
Sheppard. Similar work on a smaller scale has been continued since
1927.
Selection within self-fertilized lines was begun in 1922 and is being
continued. Varieties selected for desirable characters are self-pol-
linated, about 5 percent of the better seedlings propagated, compared,
and the superior line3 again selfed. Lines that have been selfed for
one, two, and three generations are now being grown. The principal
varieties used in this work are Belt, Chaska, Dunlap, Howard 17,
Marshall, and Minnehaha, and to some extent Beaver, Duluth, Early
Bird, Mastodon, Minnesota, and Progressive.
South Dakota
The breeding work in South Dakota (31) has consisted of an attempt
to introduce into the cultivated strawberry the hardiness of the native
strawberry of the Dakotas. Dakota No. 1 and Dakota No. 2 were
STRAWBERRIES 467
introduced, and the former, now known as Dakota, is perhaps the
hardiest variety known in the United States.
California
The breeding work in California was begun by W. T. Home and
A. G. Plakidas in 1925-26 to obtain varieties resistant to the yel-
lows or xanthosis virus disease. In recent years the work has been
carried on by E. V. Goldsmith and H. E. Thomas, and resistance to
phytophthora root rot has been made a second major objective,
varieties and selections obtained from A. F. Etter and the United
States Department of Agriculture, as well as many commercial
varieties, have been extensively used. Among the desirable characters
for California conditions not necessarily considered elsewhere are
longevity of plant, open crowns, long inflorescences, small seeds, and
heavy production in spring, summer, and fall. The work has centered
at San Jose until recently, when part of it was transferred to Davis.
Though very large numbers of seedlings have been raised and many
selections made, no varieties have yet been named and introduced.
New Jersey
Breeding work at the New Jersey Agricultural Experiment Station
(7) was begun in 1928 and has continued to the present. All available
varieties having promise for New Jersey conditions, as wToll as many
unnamed selections from other institutions carrying on strawberry
breeding, have been tested. The principal varieties used include
Aberdeen, Berri Supreme, Bliss, Bouquet, Chesapeako, Dorsett,
Fairfax, Gandy, Howard 17, Lupton, Mastodon, Parcell, Pearl,
Kedheart, Teddy Roosevelt, Wyona, and U.S. D. A. 854 and 875.
Besides published data on inheritance of earliness and lateness, data
have been obtained on sex ratios, shape, color, flavor, and firmness of
berry, and on inheritance of the everbearing characteristic. One
variety, N. J. 35, was introduced in 1936. Lupton transmitted its
size and attractiveness but also its poor quality to its seedlings.
Chesapeake transmitted its good flavor and its unproductiveness.
Many of the best very late ripening seedlings have had Pearl as one
parent. Fairfax seedlings have had high flavor and were exceptionally
firm. ^r v ,
New iork
Strawberry breeding at the New York station at _ Geneva was
begun in 1889 by C. J. Hunn and has been continued at intervals ever
since (1, 2, 54)- At least 68 named varieties, as well as many selec-
tions from crosses, have been used in the breeding work. Over 13,000
seedlings have been raised and 21 varieties have been introduced.
Several of the more recent introdxictions are grown to a slight extent,
chiefly in New York State. Clermont is grown to a considerable
extent in Erie and Oswego Counties. Catskill, however, is rapidly
becoming an important commercial variety from Maryland to Mis-
souri and northward. Most of the introduced varieties have had
Marshall or Howard 17 or both as a parent, Marshall contributing
high flavor and large size of bony, and Howard 17 productiveness
and disease resistance. In a summary of the best parents in tho
breeding work, the importance of Howard 17 as a parent is emphasized.
468 YEARBOOK, 1937
A large percentage of its seedlings produce very smooth, uniform-
shaped, glossy berries that hold up well to the end of the season. A
few selections of species have been used in crosses.
Connecticut
At the Connecticut station, Howard 17, Chesapeake, and Glen
Mary were inbred for three generations and then the F3 (third-genera-
tion) progeny were crossed. The strawberry was reported to respond
to inbreeding and crossing in much the same way as corn. The F3
plants were dwarfed, but crossing seemed to bring back the vigor that
the varieties originally possessed. From about 9,000 seedlings that
resulted from crossing the F3, promising selections have been made
and are being given field trials in different sections.
Other State Stations
At the Maine station, breeding work was begun in 1934 to obtain
better late varieties. At the Massachusetts station, breeding work
was also begun in 1934 to obtain late varieties of better dessert
quality and also better pistillate sorts.
In Illinois, breeding work to obtain varieties resistant to brown
stele root rot was started in 1935. Mastodon, Aberdeen, and Red-
heart, which appear resistant, have been used in crossing.
In Wisconsin, breeding was begun in 1933 to obtain productive
early and late commercial sorts. Howard 17, Beaver, Corvallis, and
Vanguard have been used as parents.
In Missouri, though some crossing was done at the Mountain
Grove station in 1902 and 1919, no varieties were introduced. In
1936 selections of the meadow strawberry, Fragaria virginiana, were
crossed with Aroma, Blakemore, Fairfax, Dorsett, Chesapeake,
Howard 17, and Joe, to obtain varieties with the resistance to cold,
drought, and disease, and the high flavor of the wild strawberry.
In North Dakota, small-fruit breeding began in 1920 and has
continued to the present. The Dry Weather variety, resistant to
drought, was introduced in 1928. Resistance to winter cold, summer
heat, and drought is being emphasized.
In Tennessee, strawberry breeding began in 1923 and has continued
to the present. Both selfing and crossing have been carried on to
obtain productive varieties hardy in summer, resistant to leaf and
root-rot diseases, and with attractive, firm, high-flavored berries
suitable for processing and shipping. Some selfed seedlings of Aroma
were found to be notably vigorous and productive.
At the Louisiana station breeding work has recently started with the
objective of producing varieties resistant to leaf spot and scorch, of
good shipping qualities, and sweeter than Klondike.
In Texas breeding work began in 1933 to obtain varieties resistant
to heat, drought, and leaf spot, and that would produce sufficient
runners under the climatic conditions of southern Texas.
In Washington State, at Puyallup, strawberry breeding was begun
in 1929 and has been continued to the present. The objectives have
been firm- and soft-fruited, high- and low-yielding, and red- and
light-fleshed varieties.
STRAWBERRIES 469
In Oregon, at Corvallis, breeding work has been carried on in
cooperation with the Federal work since 1928. Previously, however,
the Corvallis variety was originated by C. E. Schuster from a cross
between Marshall and Ettcrsburg 121. Schuster noted that Etters-
burg 121 transmitted its vegetative characteristics with remarkable
uniformity.
STRAWBERRY BREEDING IN OTHER COUNTRIES 6
Canada
The Central Experimental Farm of the Dominion of Canada at
Ottawa and several of the provincial experiment stations, notably the
Ontario Horticultural Experiment Station at Vineland, have carried
on strawberry breeding more or less continuously for many years.
Several recent selections made at Ottawa are being extensively tested
{21). At Vineland some 30,000 seedlings of 300 crosses and 60 open
and self pollinations were raised, 340 selections were made, and
several named (59). Two, Vanguard and Vanduke, were grown to
some extent at one time. „
England
Among private breeders in England, the firm of Laxton Bros., at
Bedford, has been prominent for its berry breeding for over 50 years,
and the varieties of strawberries originated by the firm have long been
important in Great Britain as well as on the continent of Europe, in
Australasia, and in other parts of the world. Among these, Noble,
Royal Sovereign, Scarlet Queen, Leader, Fillbasket, The Laxton,
Latest, Bedford Champion, and The Duke have been particularly
important varieties. Royal Sovereign is one of the parents of Dorsett
and Narcissa and possibly of Fairfax (16) also.
Strawberry breeding by public agencies in England is being carried
on at the Long Ashton Research Station, University of Bristol, at the
Horticultural Research Station at East Mailing, Kent, and at the
John Innes Horticultural Institution, Merton. The earliest work
was that by C. W. Richardson from 1910 to 1922, on inheritance of
characteristics in the species having seven pairs of chromosomes and
to some extent in cultivated varieties. Spinks carried on rather
extensive breeding work at the Long Ashton station. By 1923 some
5,000 seedlings had been raised and 145 selections made. He noted
that Leopold transmitted its resistance to aphids, that seedlings of
Leopold X Royal Sovereign and President X British Queen were
susceptible to mildew, but that seedlings of Leopold X Stirling Castle
were resistant to both aphids and mildew. All seedlings of V. H.
de Thury X The Earl and L. Gauticr X Wliite Perpetual were resist-
ant to mildew, andonly 1 in 60 seedlings of V. H. de Thury X King
George was susceptible. The seedlings of Bedford Champion X King
George, Leader X St. Antoine, and Fillbasket X Bedford Champion
were the best flavored. „
Germany
In Germany three stations are carrying on breeding work with
strawberries. At the University Institute for Fruit Culture, in
» Reports have been received from H. Wenholz, Sydney, New South Wales; W. S. Rogers, East Mailing
Kent, England; M. B. Davis, Ottawa, Canada: and W. S. Strong, Vineland, Ontario, Canada. Lists of
the workers and of the varieties from foreign stations are given in the appendix.
470 YEARBOOK, 1937
Berlin, quick- and early-ripening varieties with not too many flowers
are being bred for forcing houses. At the Kaiser Wilhelm Institute
in Miincheberg the breeding of large, productive, high-flavored ever-
bearers has been started, and studies are being made on methods used
in making selections, on inheritance and correlations of different
qualities, on sex ratios, and on the periodicity of the growth phases.
At the Horticultural Station at Pillnitz, under the direction of Pro-
fessor Schindler, productive, high-flavored varieties that hold their
color, that are resistant to unfavorable weather conditions, and that
ship well are the objectives. Six varieties have been named and
introduced from this station.
Australia
At _ the Hawkesbury Agricultural College, New South Wales,
breeding for resistance to diseases such as root rot and leaf scorch is
a primary objective. Seedlings of Fragaria chiloensis X British
Sovereign, Fendalcino X British Sovereign, and Southland X British
Sovereign have shown the most promise.
SUPERIOR GERM PLASM
In the strawberry, as in other plants and in animals, superior germ
plasm refers to one or more inheritable qualities that may be desirable
or useful to the grower or consumer. Thus, a variety or a species
with fine flavor, or resistance to disease or to extremes of high or low
temperature, would be counted as having superior germ plasm in that
respect. Certain characters would be considered undesirable; for
example, the one-flowered cluster of Fragaria daltoniana J. Gay.
Both of the species from which the common cultivated varieties are
derived, F. virginiana and F. chiloensis, as well as F. cuneifolia, are
extremely variable in the wild. Cultivated varieties, therefore, have
various combinations of characters, desirable as well as undesirable.
In general, the scarlet color, high aroma, tart flavor, and wide adapta-
tion to climatic and soil conditions in cultivated varieties are derived
from F. virginiana. The history of the strawberry and the success
of Btter and Georgeson, who have used new selections of F. chiloensis,
indicate that there may be many desirable characters in the wild
forms of this species that have not yet been used. Tests of selections
of F. cuneifolia and of hybrids with it indicate cold and drought
resistance, everbearingness, and quickness of response to warm spring
temperatures in this species (figs. 15 and 16). These desirable qual-
ities might extend both the range of cultivation and the fruiting season
of strawberries. As yet the collections and tests of F. cuneifolia are
too limited to fully evaluate these and other qualities that it may have.
However, hybrids of F. cuneifolia with cultivated varieties have made
strawberry production possible even at Fairbanks, Alaska (SO).
Because native species often are rather difficult to keep alive,
crosses showing hybrid vigor may be useful in holding their superior
germ plasm in breeding stock. Fragaria chiloensis is susceptible to
cold injury in Maryland. Its hybrids with Fairfax and Blakemore
are vigorous and are used as a source of the characters of F. chiloensis
in the Federal breeding work. Because F. cuneifolia becomes ever-
bearing at low elevations, it makes few runner plants, and for this
STRAWBERRIES
471
reason, too, hybrids serve as a source of its characters. Some of these
hybrids and other selections having superior germ plasm are listed in
the appendix.
Studies indicate that a variety or species showing any characteristic
actually will transmit the character to a large proportion of its seed-
lings. Crosses of varieties and species, as well as genetic research,
support the supposition that in the strawberry most qualities of
importance in breeding are quantitatively inherited, that is, that
there are genes for such qualities as flavor, color, size, firmness, etc.,
in each, or in many at least, of the eight homologous chromosomes
Figure 15. — The wild strawberry of the Rocky Mountains, Fragaria cuiivi/olia. So far
it has been little used in breeding, but it is resistant to drought and cold and is
everbearing when grown in Maryland.
(one pair in each four sets), and they have a cumulative effect. For
example, it is as if the dark Redheart contained a gene for color in
seven of the eight chromosomes, the less dark but still deep-red
Dunlap in six of the eight, the medium-red Dorsett in five of the
eight, the light-red Blakemore in four of the eight, and the White
Sugar in about two of the eight. If Redheart is crossed with a dark-
fruited variety, the seedlings are mostly dark-fruited; if it is crossed
with a light-fruited variety, the seedlings are mostly intermediate.
In making crosses, therefore, breeders have learned that if a variety
shows any desirable quality, in general that quality can be transferred
to any other variety if a large enough number of seedlings (crosses
between the two) are raised. Sometimes the seedlings nearest the
ideal are backcrossed with one or the other parent before the desired
character is obtained. The results published by Spinks (57, 58) and
by Richardson (50, 51) in England indicate that it is easier to obtain
many qualities in certain crosses than in others. Thus, Bedford
Champion X King George V gave 80 productive seedlings out of 235,
472
YEARBOOK, 1937
while Royal Sovereign X King George V gave only 8 out of 114.
Richardson obtained seedlings with the highest flavor from a cross of
Filbert Pine X King of the Earlies. Until the genetic constitution of
varieties is worked out, the location of superior germ plasm must be
assumed to he only in varieties that show it.
Because of the apparent quantitative inheritance of characters in
the strawberry, a scoring system is used in the Federal breeding work
to evaluate the qualities. A similar system was used by Keffer in
Missouri in 1893. For flavor, color, firmness, resistance to leaf spot,
resistance to leaf scorch, and vigor, seedlings are scored on a scale of
Figure 16. — Crosses of the Kocky Mountain strawberry, Fragaria cuneifolia,
with the Marshall variety.
1 to 10, 1 representing best and 10 worst. Thus, at Beltsville, Md.,
Missionary might score 3 in resistance to leaf spot, Fairfax 1.5, Howard
17 also 1.5, Marshall about 8, and Beaver 8. For flavor, Dorsett
would score 1, Howard 17 about 3, and Lupton 5. Richardson in
England used such a scoring system for strawberries, although he used
1 as poor and 8 as finest in flavor. Since the vegetative cells of garden
strawberries contain eight sets of chromosomes (seven to a set,
8 X 7 = 56 chromosomes), Richardson's scoring corresponds to the
number of sets.
Though in years past it may not have seemed possible to have
most of the desirable qualities of the strawberry in any one variety, it
now seems practicable to get most qualities in breeding stocks and
then cross these to obtain combinations of the qualities desirable for
certain conditions. The history of the strawberry bears out this
conclusion. Thus, the origination of the Wilson is considered to have
made it possible to obtain varieties both firm-fruited and productive
for different regions. The Howard 17 has added high resistance to
diseases in Northern States to the superior germ plasm. Possibly
within the next few years breeding stocks may have, in addition to
S TRA WBERRIES 473
the fairly firm fruit, the productivity, and the disease resistance
already obtained, (1) the cold-hardiness of the Progressive and of
Fragaria cuneifolia; (2) the heat resistance of Missionary; (3) the
drought resistance of F. cuneifolia and of U. S. D. A. 1791; (4) the
smoothness of flesh of Corvallis; (5) the dessert quality of Rockhill in
Minnesota and of Dorsett in Maryland; (6) the size of Marshall in
the Pacific Northwest; and (7) the tough skin of Redheart. Later
breeding may then add qualities for specific regions or uses, as the
bright color of Blakemore for a preserving and shipping sort; the deep
color of Redheart for a canning sort; the peculiar flavors — like grapes,
apricots and red and black raspberries — of crosses of U. S. D. A. 652
for novelties; the short-day adaptation of the Missionary for Florida;
the longer day adaptation of Howard 17 for other regions; and the
everbearingness and runner production of Mastodon.
In Europe the source of superior germ plasm may also be indicated
by_ the qualities for which outstanding varieties are known. Thus,
British Queen and Dr. Hogg are considered to have the finest flavor,
while Royal Sovereign and Paxton have the best flavor of the widely
raised sorts; The Duke, an early, and Waterloo, a late variety, are
of ten_ considered drought-resistant; Noble retains its color especially
well in cooking and is one of the finest flavored and most widely
adapted sorts; H. Vicomtesse de Thury (Stirling Castle), Deutsch
Evern, and Little Scarlet are considered the best for jam and are very
rich-flavored; Laxton's Latest, Late Leopold, Waterloo, and Givon's
Prolific are very late sorts; Deutsch Evern and Royal Sovereign are
superior forcing varieties; Mine. Kooi is very large and one of the
most productive but is soft and of poor quality; Laxton's Latest is
of the largest size; and Royal Sovereign, Sir Joseph Paxton, and
Dr. Morere are widely grown, productive main-crop sorts, the Sir
Joseph Paxton being frost-resistant. Late Leopold also escapes
spring frosts. The Laxton grows where most other sorts do not
succeed. Deutsch Evern is one of the best for preserving.
STRAWBERRY GENETICS AND CYTOLOGY 6
There has been little satisfactory interpretation of the inheritance of
characters in the strawberry, although there has been considerable
study of the matter (3,4,5,6). This is because most of the characters
such as color, size, shape, and structure of berry are quantitative and
determined by several genes. Three pairs of contrasting characters,
however, are available for study.
Femaleness versus various degrees of hermaphroditeness has been
extensively studied. In most cases when a hermaphrodite variety is
selfed only hermaphrodite seedlings are obtained (2, 9, 87). Female-
ness X hermaphroditeness gives in most cases at least a 1 to 1 ratio,
apparently indicating a single pair of allelomorphs located in a single
pair of chromosomes. However, hermaphroditic varieties and seed-
lings represent an unbroken series from complete fertility to complete
sterility of the pistils, and a satisfactory genetic explanation is yet to
be made. If the chromosome sets of the cultivated strawberry are
not now identical, and if pairing takes place between chromosomes in
different sets of seven, then more or less sterility would be expected.
• This section is written primarily for students or others professionally interested in breeding or genetics .
138904°— 37 31 ++
474 YEARBOOK, 1937
The unbroken series from complete sterility to complete fertility
indicates that random pairing between all the chromosomes of all
four sets actually occurs.
A second pair of contrasting characters is June-bearing versus ever-
bearing. Everbearing varieties X everbearing varieties gave at
Ottawa, Canada, 85 everbearing to 66 June-bearing, while everbearing
X June-bearing and June-bearing X everbearing gave 257 everbearing
to 788 June-bearing. The everbearing varieties are evidently hetero-
zygous and the June-bearing homozygous. Assuming that everbear-
ingness is due to two dominant complementary genes, A and B, then
the everbearing would have the composition AaBb and, selfed, would
give a 9 to 7 ratio, which was found, 85 everbearing to 66 June-bearing.
When June-bearing are crossed with everbearing, a 1 to 3 ratio would
be expected, or 261 everbearing to 783 June-bearing, which is very
close to the 257 everbearing and 788 June-bearing actually found.
In England, Bichardson selfed both the everbearer St. Antoine de
Padoue, getting 108 everbearing to 22 June-bearing, and the everbearer
Laxton Perpetual, getting 69 everbearing to 11 June-bearing. When
he crossed a June-bearing Bedford Champion with an everbearing Lax-
ton Perpetual he got 24 everbearing to 53 June-bearing. One of these
June-bearing Ft plants, when selfed, gave 8 June-bearing to 6 everbear-
ing. These numbers indicate (1) that his everbearers did not have the
same genetic constitution as those at Ottawa, Canada, and (2) that more
than two and probably four complementary genes were involved, or
that, if there were only two genes for everbearingness, they were linked.
However, too few numbers have been raised for definite conclusions.
A third set of contrasting characters may possibly be useful in
studies on inheritance, namely, normal versus variegated or chlorotic
leaves. Richardson and Clark have made some studies on their
inheritance. However, enough records have not yet been secured to
indicate the genetic composition of a variegated plant.
Strawberry Species of the World
Although about 150 species names have been applied to the straw-
berry, the most recent monograph (4%) described but 45, a number that
is undoubtedly much too large. This monograph lists 4 species for
Europe, 26 for North America, 1 for South America, and 15 for Asia.
However, many of these can hardly be separated from one another
and a total of about eight includes all the distinctive species. These
eight belong to three groups as follows:
Fragaria vesca (wood strawberry) group, 7 pairs of chromosomes:
1. F. daltoniana J. Gay, southern Asia.
2. F. nilgerrensis Schlecht., southern Asia.
3. F. vesca L., circumpolar.
Variety semperflorens Duch., Alps.
F. conformed7 Cham, and Schlecht., North America.
4. F. viridis Duch. (F. collina Ehrh.), central Europe.
Fragaria moschata (open wood strawberry) group, 21 pairs of chromosomes:
5. F. moschata Duch. (F. elatior Ehrh.), central Europe.
Fragaria virginiana (cultivated strawberry) group, 28 pairs of chromosomes:
6. F. chiloensis (L.) Duch., coast of Alaska to central California, southern
Chile, mountains of Hawaii.
7. F. cuneifolia Nutt. (F. platypetala Rydb.), Rocky Mountains.
8. F. virginiana Duch., eastern North America.
' Fragaria californica is very close to F. vesca and may be considered only a botanical variety of F. vesca.
STRAWBERRIES 475
Though these eight may include all the wild species, a final classifi-
cation must await extended field studies of Asiatic forms. Six of the
species are illustrated in figures 17 and 18.
Species With Seven Pairs of Chromosomes
The first four species have seven pairs of chromosomes (40, 62, 64)
and are in general smaller plants with thinner leaves and smaller
fruit than American cultivated varieties. Fragaria daltoniana,
F. cottina, and F. nilgerrensis belong to the F. vesca group and so far
have not appeared to have qualities of value for breeding. F.
daltoniana is unproductive, since it has one-flowered flower clusters.
The fruit of F. collina is very small, and the plants have not survived
in Maryland. The berries of F. nilgerrensis are many-seeded and
rather tasteless. The plant, however, is vigorous. A number of
varieties of the everbearing F. vesca var. semperflorens are grown to
some extent in Europe. Though the fruit is smaller than that of
American cultivated sorts, it is aromatic and borne freely throughout
the summer in the climatic conditions of northern Europe, but it has
not been successful in the United States. The fruit of F. vesca and
F. calvfornica is small — too small to be worth while.
Varieties of Fragaria moschata, the open wood strawberry of
Europe, which has 21 pairs of chromosomes, are cultivated to some
extent in European gardens for their very aromatic vinous-flavored
fruit. Though the fruit is small, it is larger than that of the alpines.
Varieties like Royal Hautbois and Black Hautbois grow fairly well
in the northern United States if protected in the winter, but they have
never succeeded commercially. La Constante, a French variety
supposedly derived from F. chiloensis X virginiana, is reported to
have much of the vinous flavor of F. moscliata and may possibly bo a
source of this flavor for breeders.
Species With 14 Pairs of Chromosomes
Species with 14 pairs of chromosomes have not been known in the
wild until recently, when Fedorova (27) reported that Petroff found
a form with 14 parrs of chromosomes, which he referred to as Fragaria
orientalis A. Los. Los., an eastern Asiatic species formerly classified
with botanical varieties of F. vesca. Longley has suggested that the
ancestral strawberry from which the others descended was close to
F. vesca. This has the basic number of 7 chromosomes in the germ
cells (diploid number 14). Lilienfeld (39, 40) recently has apparently
proved that F. moschata (F. elatior), which has 21 chromosomes in
the germ cells (diploid number 42), actually was derived in ages past
from species with 7 pairs of chromosomes. He reached this con-
clusion because, in crossing a species having 7 pairs of chromosomes
with one having 21 pairs of chromosomes, 14 chromosomes of F.
moschata paired with 14 from the vesca type, and 2 sets of 7 from
F. moschata paired with 2 other sets just as though they were a
14-chromosome species. The resulting seedlings were fertile and
constitute a new species with 14 pairs of chromosomes named by
Lilienfeld F. elnipponica Lib (derived from F. elatior, a synonym of
F. moschata, and F. nipponica Mak., which is a Japanese form of
170
YEARBOOK, 1937
Figure 17. — Native American strawberry species: A, li, Fragtiria v irfiiniimu, of
eastern North America; C, D, F. cimrifolia, of western North America; E, F,
F. iliiliiensis, of the beaches from Alaska to California and of Chile. These are
the three 56-chromosome species, from two of which the cultivated strawberry
hat descended.
STRAW BERRIES
477
Figure 18. — European and Asiatic strawberry species: .-/, B, Fragaria nilgerrensis, a
14-chromosome strawberry of southern Asia; C, D, F. vesca, the 14-chroraosome wood
strawberry of Europe; E, F, F. moschata, the 42 -chromosome open wood strawberry
of Europe. F. nilgerrensis is a rather tasteless strawberry but may possibly be of use
for breeding. From an everbearing form of F. vesca have originated the small alpine
strawberries grown in the gardens of Europe. From F. moschata have come the high-
flavored, rather small Hautbois varieties of Europe.
478 YEARBOOK, 1937
F. vesca). Yarnell also raised 14-chromosome seedlings from F. brac-
teata X vesca var. rosea, and Fedorova (27) 14-chromosome seedlings
from F. vesca X moschata.
In a similar manner East (86) was able to get pairing of one set
of chromosomes from F. vesca (n=7) with a set from F. virginiana
(n=28). Though the resulting diploid seedlings were not as fertile
as seedlings of F. vesca, the chromosomes were actually related closely-
enough to pair. Apparently through the ages since the 28-chromo-
some species originated, some changes have occurred in the chromo-
somes, but not enough to prevent pairing.
Species With 21 Pairs of Chromosomes
The only known species with 21 pairs of chromosomes is Fragaria
moschata, which has been discussed above.
Species With 28 Pairs of Chromosomes
Fragaria virginiana, F. cuneifolia, and F. chiloensis, the group from
which the cultivated strawberry has descended, each has 28 pairs of
chromosomes. F. cuneifolia is the Rocky Mountain wild strawberry,
native from Arizona to Alaska and Colorado to Oregon. It has been
used very little in breeding. However, its resistance to low winter
temperatures and drought and its everbearing character at low eleva-
tions indicate its potential value.
Many attempts hai'e been made to cross Fraga,ria vesca and moschata
with the cultivated strawberry. Such crosses have actually been
made, but in carefully controlled tests the seedlings have been entirely
or nearly sterile. However, evidence indicates that all four sets of
chromosomes of the cultivated strawberry and of the species with 28
pairs of chromosomes had a common origin and are probably homologs
of those of F. vesca. It seems entirely possible that in some cases
where cultivated varieties have been crossed with varieties of F. vesca,
true hybrid seedlings may have originated by a substitution of 7
chromosomes of F. vesca for a set of 7 of the mother plant, and, by a
subsequent doubling of the 28, a seedling with the full 28 pairs devel-
oped. If the sets are homologs, as suggested by Longley (41) and
East (85) and if those of F. resca should pair with those of the culti-
vated strawberry', the differences in seedlings might be so slight as to
be unnoticed. The everbearing crosses (Chesapeake X F. vesca and
Early Jersey Giant X. F. vesca) reported by Van Fleet may have, had
such an origin, for neither Chesapeake nor Early Giant seedlings would
be expected to be everbearing.
Chromosomes of the Strawberry
Yarnell (63) studied the chromosomes of strawberries in an attempt
to find constant differences among them and concluded that the only
constant difference was in length. He found that their small size,
their shape, and their position made even an estimate of length
difficult. He found the chromosomes of different species very similar.
The length averaged 1.7, 1.5, 1.4, 1.3, 1.2, 1.0, and 0.9 microns. The
two shorter and the longest were usually easy to distinguish, but the
others were not.
STRAWBERRIES 479
Longley (41), Yarnell, and Lilienfeld (40) all suggest that the
chromosome sets in the species with 21 pairs and 28 pairs of chromo-
somes are homologs. Longley notes also that variability is associated
with polyploidy and that the species with 7 pairs of chromosomes are
much less variable than the species with 21 or 28 pairs of chromosomes.
The diploid Fragaria are perfect-flowered, and sex differentiation
occurs only in polyploid forms. So far as the wild forms are known,
the species with 21 pairs and those with 28 pairs of chromosomes are
far more variable than the forms with 7 pairs of chromosomes, and it
is evident that variability has come in with polyploidy.
Hybrids Between Chromosome Groups
Millardet (45) in France, Richardson (48, 49, 50, 51) in England,
Solms-Laubach (56) in Austria, and Schiemann (54) in Germany have
made crosses between species of the different chromosome groups.
However, the crosses made at the Bussey Institute by East and by
two of his students, Mangelsdorf (43, 44) and Yarnell (62, 63, 64, 65),
and reported by these investigators and by Ichijima (S3, 34), cover
most of the species crossed. An outline of the crosses reported by
them follows:
Hybrids within the groups having 7 and 28 pairs of chromosomes 8
Species with 7 pairs of chromosomes:
Fragaria californica Cham, and Schleeht. X bracteata Heller (= calif ornica),
F! fully fertile.
F. californica Cham, and Schleeht. X vesca rosea Rostr., Fi fully fertile.
F. collina Ehrh. (= viridis) X maxima (?), Fi flowered.
F . collina Ehrh. X nilgerrensis Schleeht., Fi vigorous.
F. mexicana Schleeht. (= vesca) X americana alba Clute (= vesca alba or
vesca americana alba), Ft fully fertile.
F. americana alba Clute X mexicana Schleeht., Fi fully fertile.
F. vesca rosea Rostr. X americana alba Porter, Fi fully fertile.
F. vesca rosea Rostr. X mexicana Schleeht., Fi fully fertile.
F. vesca rosea Rostr. X collina Ehrh., Fi partially fertile.
F. vesca L. X vesca rosea Rostr., Ft fully fertile.
F. vesca L. X nilgerrensis Schleeht., Fi dwarfs, no flowers.
F. vesca L. X americana alba Porter, I\ fully fertile.
F. vesca L. X maxima (?) (= vesca or vesca maxima), Fi partially fertile.
F. vesca L. (Tiflis, Union of Soviet Socialist Republics) X vesca rosea Rostr.,
Fi fully fertile.
F. bracteala Heller X vesca rosea Rostr., Fi flowered.
F. bracteata Heller X americana alba Porter, Fi fully fertile.
F. bracteata Heller X collina Ehrh., Fi partially fertile.
F . bracteata Heller X maxima (?), Fi partially fertile.
F. bracteata Heller X nilgerrensis Schleeht., Fi dwarfs, no flowers.
Species with 28 pairs of chromosomes:
F. chiloensis Duch. X virginiana Duch., Fi fully fertile.
F. virginiana Duch. X chiloensis Duch., Fi fully fertile.
F. virginiana Duch. X glauca Rydb. (= cuneifolia), Fi fully fertile.
F. chiloensis Duch. X platypetala Rydb. (= cuneifolia), Fi fully fertile.
Mangelsdorf and East reported on hybrids between different
chromosome groups — 14 X 42, 14 X 56, 56 X 42 — and on generic
crosses. Fragaria vesca (2u=14) X elatior (—moschata) (2?i=42)
resulted in no Fx plant that fruited out of 600 seeds. F. vesca (2n= 14)
X chiloensis (2-n = 56) resulted in 6 nonblooming seedlings out of over
'The species names are those given by various authors, followed in some eases by identifications.
480 YEARBOOK, 1937
1,200 seeds. F. americana alba (=F. vesca alba or F. vesca americana
alba) (2m=14) X glauea (=F. cuneijolia) (2m = 56) gave only 1 plant
from 66 seeds, and it did not bloom. F. vesca (2m=14) X glauea
(2m =56) gave 5 nonfruiting plants out of 250 seeds. F. vesca rosea
(2m=14) X glauea (2m=56) gave 7 nonfruiting plants from 76 seeds.
F. vesca (2m=14) X virginiana (2m = 56) gave 21 Fi plants from 500
seeds, none of which was fertile. F. bracieata (=F. calif vrnica)
(2m=14) X virginiana (2m = 56) resulted in 10 nonfruiting plants
from 24 seeds and 2 pistillate plants that crossed with F. vesca rosea.
F. virginiana (2m=56) X elatior (2?i=42) resulted in 90 plants
from 100 seeds, many of the plants being vigorous; all those considered
hybrids were sterile.
Yarnell crossed chromosome groups as follows: 14 X 28, 14 X 42,
14 X 56, 42 X 28, 56 X 28, and 56 X 42. The 14 X 28, 14 X 42, and
42 X 28 proved to be nearly or completely sterile. The 56 X 28 cross
gave flowering plants, but none produced pink flowers as would be
expected with pink dominant. This is explained by assuming that
28 *xf 14
the crosses were hexaploid — ~ — and that there were four recessive
factors for color (pppp) and only two dominant factors (PP). In a
seedling having the composition PPpppp, the two dominant genes
would be unable to function.
Inheritance in the Species With Seven Pairs of Chromosomes
Kichardson (48) in England obtained normal hybrid segregation in
the species Fragaria vesca, with seven pairs of chromosomes. He
crossed a trifoliate with a monofoliate plant. The Ft plants were all
trifoliate. When these were selfed he got 177 trifoliate to 73 mono-
foliate instead of the expected 187.5 to 62.5. He also crossed a
white- with a red-fruited variety. The Fi plants were red-fruited
but when selfed gave 70 red-fruited to 20 white, which is close to the
theoretical 67.5 to 22.5. In crosses between single- and double-
flowered forms the Fi was single but gave 155 single to 62 double in
the F2 instead of 163 single to 54 double. A cross between runnerless
and runner-producing gave runner-producing in the Flt but 342 runner-
producing to 97 runnerless in the F2 instead of the expected 329 run-
nered to 110 runnerless. Though the above four characters showed
inheritance not far different from the expected 3 to 1 ratio, Richardson
had difficulty in classifying his F2 in a cross between pink- and white-
flowered plants. Mangelsdorf and East, however, obtained 128 pink
and 46 white in a similar cross, which is very close to the expected
3 to 1 ratio. They also crossed red- with white-fruited plants and
obtained 102 red-fruited to 56 white-fruited plants instead of 118.5
red to 39.5 white. ~ „
Generic Crosses
Fragaria vesca (m=7) X Duchesnea indica (L.) Focke (n=42) re-
sulted in 30 plants from 500 seeds, 26 being hybrids, all small and
weak. F. vesca (n=7) X Potentilla nepalensis Hook, (m unknown)
resulted in 2 seedlings from 141 seeds, but both died before flowering.
Crosses between the strawberry and the raspberry have been reported,
but the proof of such crosses has not been fully established. The
so-called strawberry-raspberry is not a hybrid but a low-growing
STRAWBERRIES 481
raspberry from China; and the so-called tree strawberry is simply a
species of tree, Arbutus unedo L., bearing fruit with a slight resem-
blance to a strawberry.
Unusual Inheritance in Fragaria
Paternal inheritance. — Millardet (23, 24, 45) reported four cases in
which the seedlings resembled the male parent. These crosses were
Fragaria vesca X Globe, F. vesca X Ananas, F. vesca X chiloensis
(n=7 X n=28 crosses), and F. moschata (elatior) X Globe (n=21 X
n=2S). Though the first two crosses gave sterile seedlings andthelast
two gave seedlings with reduced fertility, they may have been physio-
logical males or imperfect hermaphrodites, lchijima (33), working at
East's laboratory, counted chromosomes of several patroclinous hy-
brids and found them equal to the sum of the haploid numbers of the
parents. In a cross of F. vesca (rosea X alba) X virginiana, however,
lchijima found one plant with a somatic number of 56 chromosomes
that was close to F. virginiana in appearance. Yarnell has also re-
ported two octoploid seedlings from crosses of n=7 X n=28 plants.
Longley also reported a cross of F. vesca alba X Aroma where the
seedling resembled the male parent and had the same chromosome
number. Bygg and Darrow (53) found a considerable percentage
(1.2 percent) of such plants out of 3,519 crosses of cultivated varie-
ties X F. cuneifolia, both with parents with 28 pairs of chromosomes.
Waldo has also found 5 plants of the maternal, 22 of the paternal, and
6 of the hybrid types in a cross of F. chiloensis X cuneifolia. The full
explanation of this appearance of seedlings identical with or very like
the male is not yet apparent. However, an observation of lchijima
that the pollen mother cells have two nuclei, and observations by
Rudloff (52) that two complete embryo sacs were often seen, side by
side in F. virginiana and F. vesca and that they may fuse, may have
some bearing on this.
Pairing of chromosomes in an artificial polyploid. — When fertile
tetraploids originated as the result of a cross of Fragaria bracteata
(= F. vesca californica) X vesca rosea, Yarnell (64) concluded that
the four homologous chromosomes paired at random. That is, the
sets of seven chromosomes in each species were sufficiently alike so
that the long chromosomes from F. bracteata might pair with the long
ones from F. vesca rosea, and the short with short. However, a
critical review of the vesca group indicates that bracteata might better
be classed as a botanical variety, F. vesca californica, coordinate with
rosea. If this classification be made, the chromosomes of this hybrid
may be considered homologs of these botanical varieties of vesca.
Again in a cross of Fragaria vesca alba (n = 7) X virginiana (n = 28),
East obtained a diploid hybrid. Nine of the F2 were fertile, three
seedlings did not flower for the 3 years they were observed, and
seven were sterile. It is noteworthy that a set of seven chromosomes
of F. virginiana paired with a set of F. vesca alba well enough to form
some fertile seedlings. Yarnell also reported diploid hybrids of
F. vesca rosea (n = 7) X glauca (= F. cuneifolia) (n = 28) and of F.
vesca alba (n = 7) X chiloensis (n — 28).
Pairing of nonhomologous chromosomes. — Yarnell (64) reported that
tetraploid plants resulting from crosses of F. bracteata X vesca rosea were
482 YEARBOOK, 1937
crossed with three species having seven chromosomes. The seedlings
were triploids with 21 somatic chromosomes. Examination showed
that the nonhomologous chromosomes paired. Later he reported
other similar instances. Conditions were present — possibly high
temperatures — that made possible the pairing of chromosomes that
were not homologs, even though pairing of homologous chromosomes
only is supposed to be essential to the Mendelian conception of
heredity.
Production of homozygotes through induced parthenogenesis. — A
single-factor pair, Pp, was found by East (24) and his students to be
responsible for pink and white color of flower, and another pair, Rr,
for red and white fruit color in the diploid species. In crossing
F. bracteata X vesca rosea, a heterozygous red-fruited, pink-flowered
plant was obtained. Among the diploid plants produced by crossing
(F. bracteata X vesca rosea) X virginiana and X chiloensis there were 12
with red fruit and pink flowers, 3 with white fruit and pink flowers,
7 with red fruit and white flowers, and 2 with white fruit and white
flowers. Some, or more probably all, of these diploids were con-
sidered to have arisen through induced parthenogenesis, that is, the
embryo must have developed without fertilization. At the beginning
of development, then, the organism was a haploid, but because the
seedlings all proved to be diploids, the haploid chromosomes must
have divided. Thus, the seedlings were homozygotes. East (25)
points out that if a means can be found for inducing parthogenesis
from which homozygous diploids develop, it might eliminate the
uncertain and costly methods now employed to obtain plants that
are homozygous.
Bud Selection in the Strawberry
Bud selection in the strawberry has never been a method of obtain-
ing improved varieties or strains, as in apples, oranges, etc. Only a
few kinds of bud sports have been observed. Only the probable
production of an everbearing sport in the case of the Pan-American
and of a noneverbearing sport in the case of the June Rockhill have
had economic value. Another kind of sport — variegated foliage — is
a serious limitation to the value of such varieties as the Blakemore,
Howard 17, and many others. 9 Bud sports of many plants result
in the appearance in somatic tissue of recessive characters. Thus,
in the strawberry, selfed seedlings of varieties that sport to variegated
plants show a proportion of yellow seedlings. If, as the evidence
given above indicates is probable, most characteristics are quantita-
tive, then a change in a single gene in one of the eight chromosomes
is not likely to make enough of a change in the external appearance
of the plant to be noted or measured.
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486
YEARBOOK, 1937
APPENDIX
Table ].. — Past and present workers at experiment stations who have devoted or are
devoting part or ail of their time to strawberry improvement
Location
Early workers
Present workers
UNITED STATES
Federal stations:
Glenn Dale and Beltsville, Md.
Corvallis, Oreg
W. Van Fleet, George F. Waldo.
It. n. Roberts, V. K. Gardner,
C. E. Schuster, B. S. Pickett,
G. L. Kygg, George M. Dar-
Oheyenne, Wyo __ —
State stations:
Alaska, Sitka
California, San Jose and Davis.
Colorado... _
Connecticut, New Haven.
Florida, Plant City
Georgia, Experiment
C. C. Georgeson
William T. Home, A. G.
idas.
C. S. Crandall
Plak-
A. N. Brooks...
J. G. Woodruff..
Hawaii, llonolulu
Illinois, Urbana
Iowa, Ames
Louisiana, Baton Itouge_.
Maine, Orono
Massachusetts, Amherst..
Minnesota, Excelsior
J. E. Vaile
J.L. Budd, G. A. Ivins..
Missouri:
Columbia
Mountain Grove
Nebraska, Lincoln
New Hampshire, Durham
New Jersey, New Brunswick'.
New York, Geneva
Charles Haralson, M. J. Dorsey,
W. D. Valleau.
J. W. Clark, C. A. Keller..
It. F. Howard, C. C. Wiggins..
B. S. Pickett
North Carolina, Raleigh...
North Dakota, Fargo
Ohio, Wooster
Rhode Island, Kingston...
South Dakota, Brookings-
Tcnnessee, Knoxville
Texas, Winter Haven
Vermont, Burlington
Washington, Puyallup
Wisconsin, Madison
C. J. Hunn, S. A. Beach, W.
Paddock, R. D. Anthony,
0. M. Taylor.
W. F. Massey
Paul Thayer
V. W. Card, G. E. Adams
Charles Haralson
J. A. McClintock, K. M. Henry.
M. B. Cummings, E.W.Jenkins.
M. B. Hardy
FOREIGN
Canada:
Dominion Experimental Farm,
Ottawa.
Nova Scotia, Kentville..
Alberta, Lacombe
British Columbia, Sidney
Manitoba, Morden
Ontario:
Vineland.
Guelph
England:
Long Ashton, Bristol
East Mailing, Kent .. ...
John Innes Horticultural In-
stitution, Merton.
Norway, Njos, Ilermansverk
Sweden, Alnarp
Germany:
Berlin, Institute tor Tree Fruits
of the University.
Muncheberg, Kaiser Wilhelni
Institute for Genetics.
Pillnitz. Research Station for
Garden Plants.
Switzerland, Geneva
Czechoslovakia, Pruhonice
Union of Soviet Socialist Republics:
Trudy—
Mitchurin Institute
Japan
Australia: New South Wales, Sydney
W. T. Macoun, A. J. Logsdail .
F.H. Reed.
F. E. Buck.
F. S. Reeves...
D. A. Kimball.
C. W. Richardson.
H. Kihara, K. Ichijima.
George M. Darrow.
George F. Waldo.
LeRoy Powers, A. V. Tlildreth.
E. V. Goldsmith, H. E. Thomas.
D. F. Jones, W. It. Singleton.
II. P. Stuckey, U. L. Cochran,
J. E. Bailey.
A. G. Mangelsdorf.
A. S. Colby.
J. C. Miller, W. D. Kimbrough,
A. G. Plakidas.
R. M. Bailey.
A. P. French.
A. N. Wilcox, W. II. Alderman,
E. Angelo, W. G. Brierlev,
F. E. Haralson.
Paul H. Shepard, Guy Rook.
J. H. Clark.
George L. Slate, R. Wellington.
A. F. Yeager, D. If. Scott.
N. E. Hansen.
B. S. Drain, C. D. Sherbakoff.
E. Mortensen, S. II. Yarnell.
C. D. Sehwartze.
R. H. Roberts.
M. B. Davis.
W. S. Blair.
F. H. Reed.
E. M. Straight.
W. R. Leslie.
W. S. Strong, E. F. Palmer.
J. G. Maynard, G. T. Splnks.
W. S. Rogers.
P. Stedje.
C. G. Dahl.
Prof. Kemmer.
Dr. Rudorf.
Prof. Schindler.
F. Chodat.
Landovsky.
N. la. Federova.
A. Petrov, V. G. Lithovltzer.
F. A. Lilienfeld.
U. Wenholz.
Table 2. — Strawberry varieties originated by public agencies
Location
UNITED STATES
Federal station:
Belts viile, Md
State stations:
Alaska, Sitka. _
Minnesota, Excelsior.
New Jersey, New Bruns-
wick.
New lork, Geneva
Variety
Blakemore.
Bellmar
Southland..
Redheart—
Dorsett
Narcissa...
Fairfax
Oxheart
President Harding..
Duluth
Minnesota
Minnehaha
Chaska
Easypicker
Nokomis
Dcophaven...
N.J. 35
Hunn
Prolific
Magnus.. _
Quality
Addison. __
Alden
Angola
Arcade
Argyle
Ashton
Athens
Aurora
Beacon
Bliss
Boquet
Caledonia. .
Camden. _ .
Cato
Catskill....
Clermont..
Culver
Year
intro-
duced
1029
1931
1931
1931
1932
1932
1932
1933
1920
1920
1920
1922
1922
1022
1.922
1936
1895
1908
1910
191.0
1018
1918
1918
1918
1918
1918
1918
1918
1923
1923
1923
1929
1931
1929
1933
1929
1931
Parentage
Missionary X Howard 17.
.do-
Ettersburg 80 X Howard 17
Portia X Euresko
Howard 17 X Royal Sovereign.
do
Unknown
do _.
Hollis X i'ragaria chiloensis _
Pan American X Dunlap
Dunlap X Pocomoke
Minnesota X Abington
(Dunlap X Pocomoke) X Brandywine.
Dunlap X unknown
Dunlap X Abington...
Unknown. __ _
Johnson La,te X Sharpless..
Sample X Marshall
Hunn X Marshall
Hunn X Atlantic
President X Marshall
...do
...do ._
do
do__
do....
do
Seedling of Prolific _.
President X Marshall
Chesapeake X Atkins. _
Chesapeake X Pan American-
Marshall X Howard 17.
....do __ _
—.do
....do
.—do—
....do _
Superior qualities
Firm, light red, preserving, southern
Attractive, good flavor, large..
Attractive, high flavor in South, disease-resistant..
Very firm, canning, resistant to crinkle
Vigor, high flavor, disease-resistant.
do
.do-
Firm, deep red, high flavor
Productive in Alaska: firm, high flavor..
Productive, everbearer, hardy
Productive, attractive, high flavor
Vigorous, hardy, large, firm, late.
Attractive, high quality.
do __
Productive, large
Everbearer
Attractive, productive
J^ate, attractive
Very productive, attract ive
nigh flavor, large
High flavor, late
Productive, mild, largo
Productive, glossy, large
do _ _.
Productive, firm, large
Productive, glossy, large
... .do_
Productive, bright red, large
Vigorous, firm, large
Early, large, attractive
Late, high" flavor, attractive
Firm, productive
Preserving
Mild, productive, vigorous.
Vigor, high flavor
Very large, attractive, productive.
Attractive, holds up in size
Preserving, attractive
Estimated
acreage
16, 000.
200.
50.
700.
4,000.
100.
.500.
None.
Small.
Do.
Do.
Do.
Do.
Do.
Do.
20.
None.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Small.
Do.
Few acres.
Small.
Do.
10.
500.
100.
Small.
t/)
S3
ft
-J
Table 2. — Strawberry varieties originated by public agencies — Conlinued
Location
united states— continued
State stations — Continued.
North Dakota, Fargo
Oregon, Corvallis. .._.
South Dakota, Brookings
(«).
Tennessee, Knoxville
FOREIGN:
Canada:
Dominion Experimental
Farm, Ottawa.
Alberta, Lacombe
British Columbia, Sidney
Ontario:
Guelph._
V'ineland
Variety
Dry Weather.
Corvallis
Dakota No. ]
Dakota No. 2.
MeClintouk—
Bianca
Cassandra
Celia—
Cordelia
Desdemona..
Franeesoi
Helana
Hermia.
Julia
Lavinia
Lucetta
Mariana ..
-Miranda
Octavia
Olivia
Ophelia
Portia
Viola
Virgilia
Lacombe
New Victoria.
O. A. C
Valentine
Valet
Valiant
Valid....
Valonic
Valor
Vambrace
Year
intro-
duced
1925
1930
1907
1907
1932
1913
1913
1913
1913
1913
1913
1913
1913
1913
1913
1913
1913
1913
19J3
1913
1913
1913
1913
1913
1928
1930
1925
1919
1919
1919
1919
1919
1919
1919
Parentage
Americus X Howard 17
Ettersburg 121 X Marshall...
Jessie X Manitoba Wild
Glen Mary X Cavalier Wild .
Aroma selfcd
Seedling of Bubaeh.
Seedling of Bubach..
do..'
Seedling of Wm. Belt-
Seedling of Bubach
Seedling of Bubach-.
....do
Seedling of Win. Belt. ...
...do
Seedling of Win. Belt
do...
Late Stevens X Dunlap
Iloyal Sovereign X Magoon..
Parsons X Howard 17
Williams X Brandywine.
....do
Brandywine X Williams..
Dunlap X Ozark
....do
....do
— .do
Superior qnalities
Sweet, drought-resistant, everbearer
High flavor, fine texture, eanner, freezing.
Possibly hardiest variety
Hardy
Large, productive
Large, glossy, late, attractive..
Deep salmon color, productive.
Dark red, good flavor
Firm, attractive..
Firm, attractive
Productive, attractive-
Large, glossy
Large, bright scarlet
Firm, excellent eanner
Firm, large —
Deep red, large .'.._
Hardy, good preserver
Large, firm, drought-resistant -
Large, glossy, red
Excellent flavor
Large, similar to Joe
Oval, smooth
Large, dark, productive-
Light, bright color
Early. _
Estimated
acreage
2.
150.
Small.
None.
Small.
None.
Some.
None.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Some.
Do.
Do.
None.
Do.
Do.
Do.
Do.
Do.
Do.
03
CO
So
to
o
©
Van Dyke
Vanessa.
Vanguard — .
1919
1919
1919
1919
1919
1919
1919
1919
1919
1919
1919
1919
1919
1919
1919
1919
1919
1919
1919
1919
1929
do
Large, attractive
Do.
Do
M
Vanquish _ ...
Do.
00
Williams X Ozark
Do
Do.
Varangian
do ... _
Do.
0
Ozark X Williams _
Ozark X Michel
Brandywine X Michel . ... ..
Pocomoke X Ozark
do _
do... .
Early
do
do
Large _
Early
Large, bright ._ .. _
Do.
Do.
Do.
1
Vast
Do.
Do
v>
Veda
Do.
Vena
Parsons X Michel... .
Nettie X Williams
White flesh
Do.
Very late, large . .. ...
Vendor.
Do.
Vendue...
Williams X Ozark ..
High flavor, early. ... ...
Large, very late ... .
Do.
Joe X St. Louis
Do.
Do.
Manitoba, Morden
Jtosthern. _.
Prof. Jelinck
Bonmir Landovsky
Richardsons Seedling.
Czechoslovakia, Pruhoniee ...
England:
Morton, John Innes Horti-
M. Moutot X Deutseh Evern.
Kentish Favorite X Deutseh Evern
Early, hardy
Early, firm, large .
Sweet
. do
cultural Institution.
Germany, Pillnitz. .
Oberschlesien l-
1924
Large, deep red, vigorous, productive _
Erau M. Sehindler..
Pillnitz.
Early, excellent flavor.. .
do
llerbstfreude
Sweden, Alnarp.
Stella
Luna.
1933
1933 '
1934
Frau Direktor Echtermieyer X V. 11. de
Tliury.
do
I-ate Leopold X V. 11. <le Tliury...
Early, excellent flavor, productive
C/3
to
ft
to
ft
(J)
1 liaised by Max Kiebter.
Table 3. — Strau&erry varieties originated by private breeders
Name and address
C. IT. Beaver, Eau Claire, Wis.
E. C. Howard, and father,
A. B. Howard, Belchertown,
Mass.
J. E. Kuhns, Cliffwood, N. J_
George Voer, Peru, Ind_
Keith Bros., Sawyer, Mich-..
H. Rockhill, Conrad, Iowa.
Gardner Nurseries, Osage, Iowa
W. Kosuga, Sandy, Utah
A. F. Etter, Ettersburg, Calif..
Variety
Beaver. _.
Dighton..
Howard 17
noward Supreme.
Aberdeen
Mastodon
Kanner King _
Joan
Uncle Cap
Francis
Americus
Iowa
Progressive
Year
intro-
duced
Standpat
Kockhill (Wazata) .
June Rockhill .
Red Gold
Gardner 1000
Gardner 999
Bcrri Supreme
Twentieth Century.
Rose Ettersburg
Ettersburg 121.
Ettersburg 80. .
Nor-J
Ettersburg 76..
Kttersburg84._
Ettersburg 88..
Ettersburg 89. .
Ettcrsburglll.
Ettersburg 112.
1925
1908
1909
1929
1923
1921
1932
1933
1933
1910
1911
1911
1911
1914
1922
1932
1923
1918
1925
1929
1930
1903
1907
1912
1913
1913
1913
Parentage
Howard 17 X Burrill.
1913
1913
1913
Crescent X Howard No. 1.
Howard 103 X Howard 17..
Kellogg Prize X Superb_
Ananas de Guemene X Mastodon.
Mastodon seedling..
Louis Gautier X Pan American
.do..
Dunlap X Pan American.
Pan American X Dunlap..
.do..
Progressive X Early Jersey Giant.
Rockhill sport
noward 17 X Everbearer..
Superior qualities
Estimated acreage
Hardy, productive, good shipper..
High flavor
Bcrri Supreme X Rockhill
(Sharpless X Parry) F3 X Fragaria
chiloensis, Peru.
Derived from F. chiloensis X ?
In part at least from Rose Ettersburg
and a selection of F. chiloensis.
Fendall X Ettersburg 121
(Michel 1 X Rose Ettersburg) X F.
chiloensis.
Sister to Ettersburg 80
Dornan and F. chiloensis.
Sister to Ettersburg 80. . .
do
Early, productive, large, attractive, frost and
disease resistant.
Productive, high flavor, excellent for freezing
Productive, resistant to brown stele disease
Productive, everbearing, produces runners freely.
Dark red, firm, canner
Large, everbearing
Large, sweet, everbearing
Very good flavor, everbearing, early _
Excellent flavor, everbearing
Everbearing
Everbearing, vigorous, very hardy, excellent
flavor, early, healthy.
Everbearing, large
Everbearing, large, one of best flavored berries in
United States, large, disease-resistant, very
hardy.
Noneverbearing, but like Rockhill otherwise
Sweet, large. _
Everbearing, propagates freely __ __
Everbearing, high flavor __.
Everbearing _
do. „ :
Vigorous, productive, fragrant, drought-resistant,.
Vigorous, many crowns, hardy foliage, best canner
in United States, solid, high flavor, very late.
Vigorous, large, healthy foliage, solid flesh, largo...
Productive, firm .
Vigorous _
Firm, pale __
Vigorous, few runners
Productive, drought-resistant.
Large, glossy
2,000.
32,000.
2,000.
1.000.
Small.
None.
Do.
Do.
200.
O
None.
200.
Small.
20.
None.
250.
Little in the United
States, but some in
Australasia.
None.
Do.
Do.
Do.
Do.
Do.
Do.
to
bo
©
\o
Cm
^1
Ettersburg 91 . .
Ettersburg 71 . .
Ettersburg 75..
Ettersburg 79. .
Ettersburg 88..
Ettersburg 93. _
Ettersburg 94 __
Ettersburg 108.
Ettersburg 114.
Ettersburg 116 .
Ettersburg 200.
Ettersburg 330.
Ettersburg 450
Ettersburg 904
Euresko (Eurisko).
Beaderarena
Califour
Deleeto —
Fendalemo
Beaderarena, Jr.
Fantastic
Ossie
Cream
Fendaleino
Kalieene...
Lnge ..-
Ked Cross—
Rena
Trebla
White Sugar
Red Sugar
Late Cross
Redfour
Von Humboldt.
Alcatraz.-
Wickson.
Golden Gate.
Elinor
Hard
Kandykid
New Deal
1914
1914
1914
1914
1914
1914
1914
1914
1914
1914
1914
1016
1916
1918
1918
1918
1918
1918
1S20
1920
1920
1920
1920
1920
191 «
1920
1930
1930
1933
1933
Gracilis.
1935
1935
.do..
(Michel i X Rose Ettersburg) X -/•'.
chiloensis.
do
Win. Belt cross
Sister to Ettersburg 80
Rose Ettersburg X F. chiloensis
do
Rose Ettersburg X Michel1 X—
Sister of Ettersburg 94
Dunlap X F. chiloensis, Peru
Ettersburg. 24 (Michel X Rose Etters-
burg) cross.
Chesapeake X Ettersburg 20 (Rose
Ettersburg X F. chiloensis).
F. chiloensis X Bederwood
Ettersburg 88 X 2
Seedling of Beaderarena. ._
Fendall X Ettersburg 121
Seedling of Ettersburg 84__
Ettersburg 330 X Trebla
Fendall X Ettersburg 121
Ettersburg 210 X Trebla or Etters-
burg 121 X Trebla.
Unknown
Ettersburg 210 X Trebla
Probably F. chiloensis X Ettersburg 84.
Ettersburg 114 X Ettersburg 84
Unknown
Cross of Ettersburg 80
Seedling of Red Cross
Ettersburg 121 X Trebla
(Rose Ettersburg X F. chiloensis) X
cross of similar parentage.
Red Sugar X Kalieene
(Red Sugar X Ettersburg 121) X F.
cuneifolia.
Red Sugar X Kalieene
Probably Red Sugar X Ettersburg 121
or Trebla.
F. chiloensis hybrid.
i Not true Michel, as Mr. Etter reports it as pistillate, while Michel is perfect-flowered.
Deep red, high flavor, drought-resistant.
Cap or calyx stays on plant, light pink..
Red to center, firm
Deep red, high flavor
Deep red, canning variety
Deep, glossy red
Very attractive, aeid ___
Vigorous, pink, evergreen ._.
Similar to Ettersburg 94
do
Pink, productive, deep-set seeds..
Excellent flavor, large, firm, attractive.
Sweet, very firm.
Deep red to center, firm
Very hardy foliage, attractive
Deep red, blaek-raspberry flavor _
Juicy, high flavor, late
Deep red, vigorous
nigh flavor, sweet
Vigorous, large
Meaty flesh, early, showy
Yellow cream color, productive, late
Large, resistant to heat, productive
Early, solid flesh, very productive, red center,
vigorous.
Canning, solid, brilliant red, firm _
Very glossy, sweet, attractive, uniform shape —
Eight pink, similar to F. chiloensis, late
Firm, solid, productive, frost-resistant
White to pink, sweet, firm, large, late
Late, resembles Ettersburg 80
Large, eanner, early.
Evergreen, heavy foliage, vigorous..
Meaty
Evergreen, heavy foliage, firm.
Firm, high flavor, large..
Pink .
Firm, meaty
Deep red, firm, canning.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
CO
Do.
H
Do.
1=3
Do.
Do.
^
Do.
Do.
^
Do.
to
Do.
tq
Do.
fci
Do.
las
Do.
i— 1
Small.
None.
fcq
Do.
C/2
Do.
Do.
M5
Table 3. — Strawberry varieties originated by private breeders — Continued
Name and address
Thomas Laxton, Bedford, Eng-
land.
to
Variety
Traveller
Exquisite
Pioneer
Noble
Captain
A. F. Barron
Jubilee
King of the Earlies. _
Commander
Competitor
Scarlet Queen
White Knight
Royal Sovereign
Latest of All
Monarch
Leader
Laxton No. 1
Bedford Champion..
Mentmore...
Fillbasket
Reward
Trafalgar
Climax
The Laxton .-
The Bedford.
Latest
Progress
Cropper
Reliance
Year
intro-
duced
Perpetual
Profit
Rival.
Utility
Connoisseur..
Epicure
Pine Apple-
Unique
The Count—
Maincrop
The Earl
1872
1874
1876
1884
1884
3885
3887
1888
1889
1890
1891
1891
3892
3894
1895
1895
3904
3906
3907
1907
1907
1908
1909
1909
1909
1909
1909
Parentage
La Constante X Napier...
1910
1911
Seedling of Sharpless
Crown Prince X Foreman Excelsior.
Sir J. Paxton X Sir C. Napier
Vicomtesse X Black Prince
British Queen X President
Kerr Prolific X Foreman Excelsior...
King of the Earlies X Noble
King of the Earlies X Noble
Noble X King of the Earlies
British Queen X Helena Gloetle
Latest of All X Captain
Latest of All X Noble
Noble X May Queen
Seedling (Scarlet Queen X John Rus-
kin) X seedling (Noble X Sir J.
Paxton.)
Noble X British Queen
Royal Sovereign X Latest of All
Royal Sovereign X British Queen
J^atestof All X ?
Latest of All X Waterloo
Royal Sovereign X Sir J. Paxton
Dr. Hogg X Napier
Ivatest of All X seedling _
British Queen X Latest of All
Seedling X Fillbasket
V. H. de ,Thuiy X seedling of St.
Joseph.
Monarch X St. Joseph
Sir J. Paxton X Countess
Givons Late X Royal Sovereign .
Seedling 500 X Waterloo
Scarlet Queen X Fillbasket
British Queen X Fillbasket
Superior qualities
Bedford Champion X The Laxton...
Waterloo X Royal Sovereign
Deep scarlet-
Large, attractive
Large, attractive, productive, wide adaptation.
Most attractive of all, early
Glossy, scarlet
Late
Very early, high flavor
High flavor _
Early, attractive, high flavor
Light scarlet X white
Large, bright, scarlet, firm, high flavor.
Late, very large, crimson, productive...
Large, attractive
Large, deep crimson, sweet..
Earliest _
Very large, scarlet, sweet.
Estimated acreage
Crimson.
Scarlet, productive-
Large, high flavor, attractive
Late, large, attractive
High flavor, large, firm
Large, firm, vigorous
High flavor, scarlet..
Very large, week later than Waterloo-
Late, bright scarlet, large
Productive, large, crimson
Productive, scarlet
Large, sweet
Firm, productive, deep scarlet.
High flavor, late, deep scarlet. _
Firm, high flavor..
Excellent flavor, bright scarlet.
Excellent flavor
Excellent flavor, bright scarlet.
Crimson
. ...do
High flavor, large
Preserving
£
to
to
©
©
-<1
The Admiral
^^' trite Perpetual.
Everbearing
International
King George V...
The Duke
Tit Bit
Victory
Sir Douglas Haig.
Marshal Foch
Lord Beatty
Laxtonian
Bountiful
Abundance
Omega
Majestic
Rearguard
Robust
Empress ...
Proline
Duchess of York.
Primate
Acquisition
The Queen
19U
19 IB
1910
19 IB
1918
1910
1918
1919
1919
1920
1920
1921?
1921
1922
1S23
1924
1925
1925
1925
1926
1927
1928
1929
19i9
Seedling X Bedford Champion..
Louis Gauthier X St. Antoine..
Latestof All X seedling
Royal Sovereign X Louis Gauthier..
Seedling X Bedford Champion
Reliance X Bedford Champion
Seedling X British Queen
Seedling X Dr. Hogg
The Bedford X Sir Joseph Paxton...
Seedling X Bedford Champion
Seedling X seedling. _
D X D_..__ _
Fillbasket X The Earl
Seedling X Bedford Champion.
Seedling X International
Latest X Omega
Bedford Champion X Bedford
Seedling X seedling
do
Laxtonian X Duke ..
Seedling X seedling
do
"Waterloo X Queen of Denmark
High flavor, productive, large
Nearly white, everbearing
High flavor
Bright scarlet, firm, high flavor
Bright scarlet, forcing, early
Early, high flavor, scarlet, forcing. _ _
High flavor, scarlet
Crimson, sweet _
Scarlet, yellow seeds, sweet
Firm, dark... _
Light red—
High flavor, glossy, crimson, firm, Ian
Scarlet, large
High flavor, large, sweet
Latest, sweet, scarlet, firm
Bright, crimson, sweet, firm..
Late, sweet, productive
Crimson, sweet
Firm, preserving
Scarlet, sweet, resists mildew
Bright scarlet, drought-resistant
Firm, sweet, bright crimson... __
Vigorous, disease-resistant... _
High flavor, pale scarlet '__
to
til
to
tq
t/2
494 YEARBOOK, 1937
Sources of Superior Qualities in Strawberries
Note.— Though the following varieties and species are notable for superior qualities, it may be that they
will not prove to be equally good transmitters of these qualities.
Plant characteristics:
Hardy against cold: Fragaria cuneifolia selections and crosses (Beltsville, Md.,
Corvallis, Oreg., Fairbanks, Alaska, and Cheyenne, Wyo.); /''• virginiana selec-
tions (Fargo, N. Dak), Dakota, Dry Weather, Dunlap, Rockhill, Progressive,
Parsons (Gibson), Beaver, Camden, Culver, Minnehaha.
Resistant to frost: Howard 17 and Chesapeake in United States, Sir Joseph
Paxton in England.
Resistant to verticillium wilt: Chilean (F. chiloensis) .
Resistant to brown stele (Phyiophthora): Aberdeen, Mastodon, and Redheart
in Illinois; Leopold and Oberschlesien in Scotland.
Resistant to leaf scorch: Southland, Fairfax, Howard 17, Dorsett. U. S. D. A.
1142 (652 X Ettersburg 450), 1572 (Howard 17 X Dorsett), 2124 (Chesapeake
X Fairfax).
Resistant to leaf spot: Southland, Fairfax, Howard 17, Rockhill, U. S. D. A.
1142 (652 X Ettersburg 450), U. S. D. A. 2120 (Chesapeake X Fairfax), U. S.
D. A. 2124 (Chesapeake X Fairfax).
Resistant to mildew: Marshall and Rockhill in the United States; V. H. de
Thury (Stirling Castle), McMahon, and Aberdeen Favorite in England.
Resistant to aphid: Late Leopold, Bedford Champion, Aberdeen Standard,
John Ruskin, Marshal Fooh, and Sturton Cross in England.
Resistant to mite: Marshall in California; Mme. Kooi, Laxtonian, and Ober-
schlesien in England.
Resistant to crinkle: Redheart, Rockhill, and some F. chiloensis hybrids in
Oregon.
Resistant to yellows (xanthosis): Nick Ohmer, Bellmar, and probably some
F. chiloensis hybrids in California.
Resistant to heat: Missionary, Klondike, Blakemorc, Southland, U. S. D. A.
1142 (652 X Ettersburg 450).
Resistant to drought: F. cuneifolia, U. S. D. A. 1791 (Ettersburg 904 X Howard
17), Marshall, Gold Dollar; The Duke and Waterloo in England.
Greenhouse forcing: Marshall in the United States; Royal Sovereign in Europe;
Deutsch Evern in frames in the Netherlands; Noble in low houses in Germany.
Adapted to short days: Missionary, Klondike, Blakemore in the United States;
Chilean in Ecuador.
Fruit characteristics;
Early ripening: U. S. D. A. 2267 (Missionary X Fairfax), U. S. D. A. 1631
(Howard 17 X Dorsett), Michel, Blakemore, Dorsett, Howard 17, Ozark, Pro-
gressive, Rockhill, Beaver, Early Bird, Minn. 1200; Deutsch Evern, Avant
Tout, Laxton No. 1, and The Duke in England; Sir John Ruskin in Scotland.
Late ripening: U. S. D. A. 2263 (Ettersburg 904 X Fairfax), U. S. D. A. 2124
(Chesapeake X Fairfax), F. chiloensis and its crosses (Corvallis, Oreg., and New
Brunswick, N. J.), Ettersburg 121, Wyona, Pearl, and Gandy. Omega, Latest,
Utility, Jucunda, Rearguard, Givons, Waterloo, and Leopold in England.
Firm: U. S. D. A. 2166 (Joe X Redheart), U. S. D. A. 2120 (Chesapeake X
Fairfax), Redheart, Fairfax, Blakemore, Minnehaha, U. S. D. A. 2161 (Joe X
Redheart). Many Chesapeake X Fairfax and Blakemore X Fairfax selections
have firm fruit.
Large: U. S. D. A. 2132 (652 X Fairfax), N. C. 337 (Bellmar X Fairfax),
Catskill, Dorsett, Marshall, Minnehaha, Minn. 1201 (Marshall selfed). Latest
and Laxtonian in Europe.
Yellow seeds: Blakemore, Chesapeake, U. S. D. A. 2061 (652 X Ettersburg
450), U. S. D. A. 1591 (Howard 17 X Dorsett), U. S. D. A. 2126 (Chesapeake X
Fairfax).
Light scarlet color: Blakemore in United States; Royal Sovereign, Ffllbasket,
The Duke, The Queen, King George V in England.
Superior qualities for freezing: Fruitland, Joe, Big Late, Klondike in eastern
United States; Howard Supreme in Massachusetts; Corvallis, Redheart (sliced),
Marshall in Oregon and Washington. Also, selections from Blakemore X Etters-
burg 450, Southland X Blakemore, Blakemore X Marshall, Blakemore X Klon-
S TRA WBERRIES 495
dike, Redheart X Ettersburg 121, Blakemore X Ettersburg 121, Ettorsburg 121
X Clark, Clark X Narcissa, and Howard 17 X Marshall in Oregon.
Superior qualities for preserving: Blakemore in United States; V. H. de Thury
and Deutsch Evern in Europe. Reported good in some localities: Culver and
Dorsett in United States; Lacombe in Canada. Marshall and Missionary are
extensively used for preserving, though they are not equal to Blakemore. Crosses
of Blakemore with other varieties have proved superior for preserving.
Superior qualities for canning: Redheart, Corvallis, Ettersburg 121 in the West;
Portia in the East. Reported good in some localities: Culver, Redfour, Lnge,
Trebla. Probably Noble, Scarlet Queen, and Paxton in parts of northern Europe.
Crosses of Narcissa X Ettersburg 121, Redheart X Ettersburg 121, and Oregon 14
(Ettersburg 121 X Marshall) X Narcissa have produced good canning selections
in Oregon.
Excellent flavor: Dorsett, Fairfax, Rockhill, Southland, Marshall, Corvallis,
U. S. D. A. 1008 (F. chiloensis X Progressive), U. S. D. A. 1128 (Howard 17 X
Ettersburg 450), U. S. D. A. 2183 (Missionary X Howard 17). British Queen,
Dr. Hogg, Scarlet Queen, Connoisseur, Epicure, Pineapple, The Duke, Aberdeen
Standard, and Royal Sovereign in Europe.
Unusual flavors: U. S. D. A. 1021 (Kalicene X Howard 17), grape flavor; U. S.
D. A. 1026 and 1028 (Howard 17 X Ettersburg 450), apricot flavor; U. S. D. A.
1145 (652 X Ettersburg 450), raspberry flavor; Calif our, black-raspberry flavor.
BLACKBERRY AND
RASPBERRY IMPROVEMENT
GEORGE M. DARROW, Senior Pomolo-
gist, Division of Fruit and Vegetable Crops
and Diseases, Bureau of Plant Industry 1
E,
BLACKBERRIES, INCLUDING DEWBERRIES
iXCEPT for the Logan (Loganberry), cultivation of the blackberry
is chiefly limited to North America and most varieties of blackberries
have originated in this country. Hedrick (SI) 2 states that the black-
berry came into cultivation little by little early in the nineteenth
century. It became more common as a cultivated fruit about 1850,
when several selections from the wild were introduced into cultivation.
Among these was the Lawton, which is still grown. The Snyder
variety was introduced about 1860, the Eldorado before 1891, and the
Lucretia trailing blackberry or dewberry about 1875. These, as well
as almost all others that have been grown commercially, were selec-
tions from the wild. Wilson Junior, raised from seed of Wilson Early,
and Minnewaski, grown from seed at Marlboro, N. Y., have resulted
from efforts to improve this fruit in Eastern States, but neither
variety is now grown commercially to any extent.
In the West, efforts to improve the blackberry have met with much
greater success. Selections of the wild trailing blackberry were first
grown. Among these was the Aughinbaugh. In 1881, J. H. Logan
raised the Logan and probably the Mammoth from seed of the Aughin-
baugh. A second generation was raised from some of the seedlings,
and from these the Black Logan and other promising varieties were
selected. The Logan is still important, but the Mammoth is only
occasionally grown now. The Black Logan may possibly still be
raised, either as Black Logan or under other names. In 1897 Luther
Burbank introduced the Phenomenal, ^ very similar to the Logan.
This was widely grown for a while, but it has largely disappeared.
About 1926 the Young dewberry (Youngberry) or trailing black-
berry was introduced. This is a hybrid between the Phenomenal and
the eastern Mayes dewberry (Austin Mayes), made by B. M. Young,
of Louisiana. In 1935 the Boysen (Boysenberry), very similar to the
Young, was introduced. Its origin is unknown.
In Oregon, Washington, and New Jersey the Evergreen or Black
Diamond is cultivated. It is a very old variety from England that has
1 Many experiment station workers and private breeders have contributed records and information.
To these the writer is most grateful. A mong those especially generous of their time were George L. Slate and
L. M. Cooley (New York), J. H. Clark (New Jersey), A. S. Colby (Illinois), E. Angelo and A. N. Wilcox
(Minnesota), C. P. Williams (North Carolina), and George F. Waldo (Oregon). W. J. Strong, M. B.
Davis, N. H. Grubb. C. G. Dahl, and P. Stedje contributed information on work at foreign stations. ]! M
Young (Louisiana), H. Eockhill (Iowa), W. E. Lammertz (California), and George Pyne, of Topham
Devon, England, have all contributed information.
1 Italic numbers in parentheses refer to Literature Cited, p. 523.
496
BLACKBERRIES AND RASPBERRIES 497
become widely naturalized west of the Cascade Mountains in Oregon
and Washington. In California, and to a slight extent in Oregon and
Washington, the Himalaya {Rubus procerus P. J. Much1.) is raised.
This is considered identical with the Theodor Reimers variety of
Germany. It also is widely naturalized west of the Cascade Mountains
Besides these two, several other European varieties that have been
named in recent years have been tested, but no others have succeeded
in the United States. In 1932 the Brainerd, a hybrid between the
Himalaya and an eastern variety, was introduced. Thus, except for
the Logan, Phenomenal, Young, Brainerd, and possibly the Boysen,
the cultivated varieties of blackberries have originated as chance
seedlings in the wild.
At present the Eldorado (Stuart) is the leading blackberry of the
eastern erect type, Lucretia the leading trailing blackberry or dew-
berry of the eastern group, Logan and Young the leading trailing
varieties of the western type. The Evergreen (Black Diamond) is
the leading variety of the European type.
American Wild Blackberries and How Varieties
Originated From Them
The wild blackberries of North America fall into five major groups:
(1 ) The erect or nearly erect types, like Early Harvest (fig. 1 ) and
Eldorado, of the eastern United States from Florida to Canada and
from the Atlantic coast to the Prairie States; (2) the eastern trailing
blackberries, not red-hairy caned, much like the Lucretia, having
about the same range as the erect ones; (3) the southeastern trailing
blackberries having red hairs on the canes, like the Manatee and
Advance, ranging along the Atlantic and Gulf coasts from Delaware
to Texas; (4) the trailing blackberries, from which the Logan is
derived, of the Pacific coast from Canada to southern California;
and (5) the semitrailing Evergreen (Black Diamond) and Himalaya
IN SPITE of the fact that a good deal has already been accomplished,
the possibilities of improving the red raspberry by utilizing the
available cultivated varieties in further breeding work are still
enormous. Some of the qualities, now found separately, that may be
combined in raspberries of the future are the very large fruit size
of European varieties and newer American productions, immense
fruit clusters, great productiveness, firmness, vigor, and resistance to
diseases. But there is also a large reservoir of germ plasm, hardly
yet touched by raspberry breeders, in the wild species of Asia and
elsewhere, some of which resemble the grape, hawthorn, bamboo,
maple, and apple in their leaf forms, and vary from low and soft-
stemmed plants to plants with stems 3 inches thick and 14 feet
high.
498
YEARBOOK, 1937
of Oregon, Washington, and California, that have been naturalized
from Europe and which have become serious weeds of roadsides,
Sastures, and open forests. There are no native blackberries in the
locky Mountains of the United States.
Originally, when North America was settled, most of the wild
blackberries could be classified into a few relatively distinct species,
and though blackbcr-
riesweregathered from
the wild, they were
nowhere as abundant
as at present. When
the forests were cut
and the land was
cleared for pasture
and meadow, the chief
cover in many north-
ern sections for sev-
eral years was the wild
blackberry. Birds ate
the berries and drop-
ped the seeds in the
brush. These clear-
ings of forest and
pasture gave the op-
portunity for seedlings
of different wild spe-
cies to grow side by
side, as they had not
when dense virgin for-
est covered the land.
Normally, the wild
blackberries of the
East are entirely or
nearly self-sterile, and
those of the Pacific
coast have male and
female organs on sep-
arate plants. All need
cross-pollination. In
the clearings and pas-
tures bees and other
insects have crossed
the blackberry species
for the last 100 to 300 years, and hybrid seedlings have grown up,
so that immense numbers of hybrids may now be found. These
hybrids vary from sterile to productive plants, and many are extremely
vigorous. Backcrosses between a hybrid and one parent and crosses
between hybrids are also appearing. Thus man, by clearing the
forest, has started an immense breeding project. For the last 75
or 80 years man has been cashing in on this project by selecting the
best of these wild hybrids and trying them under cultivation. Always
he has overlooked the fact that the wild species were cross-fertilized.
Figure 1. — Early Harvest, derived from the eastern ercrl
blackberry.
BLACKBERRIES AND RASPBERRIES 499
Two or more selections were not planted together, so that many of
the selections, when propagated by themselves under cultivation,
were not productive. Furthermore, most of the wild blackberries
are woodland plants, fruiting best in the leafmold at the edge of the
forest and along streams. No wonder many of the selections were
unproductive under cultivation. Through scores of years, however,
selections of species and of hybrids have been found that have been
productive when grown by themselves in open fields. In the South
no productive selection that will set fruit by itself has yet been made
of the trailing species with red-hairy canes. When the Kogers or
Advance is grown, two or more selections are actually interplanted
and cross-pollination is thus made possible, but many growers are
unaware of this fact.
There is no final agreement as to just how many botanical species
should be recognized, because the species have hybridized freely.
Brainerd and Peitersen (6) list eight erect or semierect and four
trailing species for New England. Canes of these species are shown
in figure 2 . Their survey of the wild forms was extensive and thorough
and was supplemented by experiments on the effect of environment
on botanical characters and by studies in hybridization. It seems best
to follow their classification and viewpoint. The qualities of possible
value to breeders are briefly described for several species as follows:
The "high-bush" or "black-long berry", Rubus allegheniensis Porter. — Canes
strong, erect growing, with stout prickles; leaves mostly very large and strongly
heart-shaped; clusters largest of American blackberries, 14- to 18-flowered;
fruit large, long, sweet, and one of the best. Common in fields and pastures
from New England to Wisconsin, but ranging from Minnesota to Nova Scotia
and in the mountains to North Carolina and Tennessee. This is one of the purest
and most distinct of northeastern erect blackberries. Snyder, though probably
a hybrid, is close to the wild type, while Ancient Briton, Eldorado, Taylor,
Agawam, Jumbo, Lawton, Stone, and Wachusett are probably hybrids of this
species with others. Albino forms are fairly common in the wild.
The "tall" blackberry, Rubus argutus Link. — Canes very erect, deeply furrowed,
prickly; clusters 8- to 12-flowered; fruit often with bitter aftertaste" This, or
closely related forms, is the most common blackberry of the roadside and fields
of the eastern United States. Early Harvest is close to the wild type of this
species, while Erie is probably a hybrid.
The "short" or "square-fruited" blackberry, Rubus pergratus Blanch. — Canes
tall and arching, prickly; leaves large and broad; clusters 8- to 12-flowered; fruit
short, cylindric. A hardy blackberry of the higher elevations in New England,
New York, and Pennsylvania, with large but short fruit of excellent flavor.
It does not seem to be represented in cultivated varieties.
The "leafy-flowered" blackberry, Rubus frondosus Bigel.— Canes arched and
recurving, prickly ; leaves broad; clusters 8- to 12-flowered; fruit not so large as that
of the above species. This is the common blackberry of the fields of New England,
and next to R. argutus the most common of the blackberries of the eastern United
States. It seems to thrive better than most species in the open fields. It has
probably hybridized most extensively with R. argutus. Varieties nearest to
the wild types are Joy, La Grange, Ward, and Watt, while most of the varieties
listed above as hybrids of R. allegheniensis are probably hybrids with this
species.
The "thornlcss mountain" blackberry, Rubus canadensis L. — Canes erect to
arching, without prickles; leaves without hairs; leaflets long with long stalks,
especially the terminal one; clusters loose; fruit long, tart. This thornless or
prickleless blackberry is native to the higher mountains from Georgia northward
to Newfoundland and Quebec, but is found at the lower elevations from northern
Maine west to Wisconsin. It is a forest plant and does not succeed well at the
lower elevations in open fields. Its fruit is excellent and the plant is very hardy
northward. No variety derived from this is now under cultivation.
500
YEARBOOK, 1937
Figure 2. — Canes and prickles of 12 eastern species of the blackberry group (Eubatus
section of genus Rubus): a, Rubus allegheniensis; b, R. argutus; c, R. pergratus; d, R
frondosus; e, R. recurvans; f, R. canadensis; g, R. elegantulus; h, R. verrnontanus; i, R.
setosus: j, R. hispidus; k, R. procumbens; I, R. baileyanus. (After Brainerd.)
BLACKBERRIES AND RASPBERRIES 501
The "Vermont" blackberry, Rubus vermontanus Blanch. — A rather rare black-
berry with recurving canes that has small but very numerous fruits. It is found
at the higher elevations from New York to Nova Scotia and is quite hardy.
The "sand" blackberry, Rubus cuneifolius Pursh, is native along the coast from
Connecticut to Texas and is not fully hardy in the North. It has very erect and
quite thorny canes, and the fruit ripens much later than that of other American
blackberries. In fact this species, with its often pink flowers, grayish foliage,
and late fruit, is the closest of any to the European group of blackberries. Eureka
belongs to this species, and Nauticoke is close to it.
The dewberry or trailing blackberry, Rubus baileyanus Britt. — Canes trailing,
prickly; clusters one- to three-flowered; seeds large. This is one of the probable
parents of the cultivated dewberries Mayes and Lucretia, which arc probably
hybrids of R. baileyanus with R. arguPus. It is one of about three widely distrib-
uted trailing species in the eastern United States.
The "southern red-caned" dewberry, Rubus trivialis Michx. — Canes trailing,
prickly, usually with dense red bristles, often evergreen; flowers largo, usually
solitary; fruit large, long, very early. This species, like the sand blackberry, is
native along the coast from Maryland to Texas, but extends up the Mississippi
Valley to Arkansas and southern Missouri. It has large, long fruit that ripens
earliest of all. The Advance, Rogers, and Manatee all belong to this species.
The Advance and Rogers have extremely firm fruit in several-fruited clusters
and are apparently immune to double-blossom or rosette disease.* The limitations
of the species are usually 1-flowcrod clusters, entire self-sterility (84), lack of
hardiness except in the South, and prevalence of the double-blossom or rosette
disease in the South.
The trailing blackberries or dewberries of the Pacific coast, Rubus ursinus Cham.
and Schlecht., R. macropetalus Dougl., and R. loganobaccus Bailey. — Canes trailing,
prickly, nearly evergreen; clusters usually 5- to 10-flowered, with sexes on separate
plants; fruit to V/% inches in length, deep wine colored to black. All three species
arc very subject to loaf spot and anthracnosc, which limit their culture in the
Eastern States. R. macropetalus occurs mostly in Oregon, Washington, and British
Columbia, and R. ursinus and R. loganobaccus in California. All have highly
flavored tart berries, the Logan being derived from R. loganobaccus, which occurs
from about Watsonville north to the California-Oregon State line. The Young,
Boysen, and Cameron derive their fine flavor from this latter species. Cazadero
and other varieties have been derived from R. macropetalus.
The probable derivations of cultivated varieties are:
Rubus allegheniensis X argutus: Ancient Briton, Eldorado, Taylor.
R. allegheniensis X frondosus: Agawam, Erskine Park, Jumbo, Lawton, Snyder,
Stone, Wachusctt.
R. argutus X frondosus: Blowers, Erie, Mcrsercau.
R. baileyanus X enslenii Tratt. : Promo.
R. baileyanus X argutus: Mayes, Lucretia.
R. argutus: Early Harvest.
R. frondosus, or (R. frondosus X argutus) X R. frondosus: Jov, La Grange, Ward,
Watt.
R. cuneifolius: Eureka, Nanticoke (possibly R. cuneifolius X argutus).
R. trivialis: Manatee, Rogers, Advance.
R. loganobaccus: Logan.
R. loganobaccus X (R. baileyanus X argutus): Young, Boysen.
Great Names in Blackberry History
The important names in blackberry history include W. O. Focke,
H. Sudre, E. Brainerd and A. K. Peitcrsen, L. H. Bailey, B. Lidforss,
J. H. Logan, and B. M. Young.
Focke was a German botanist with a broad viewpoint who made the
study of the systematic botany of the blackberry-raspberry group a
large part of his life work. He {25) divided the genus into subgenera
and species in an understandable way. Ho described 132 species of
> Double-blossom or rosette disease is caused by a spocics of Cercosporella fungus which infects the buds
causing a rosette or witchos'-broom type of growth. The infected blossoms Income distorted and are sterile.
502
YEARBOOK, 193 7
blackberries. He gave a discussion of the origin of European black-
berries to which reference is made in the appendix.
Sudre (54), a French botanist, confined himself to the European
blackberries. He tried to determine the original species of Europe
by a study of their distribution and relationships and of the percentage
of good pollen in their flowers. He described 1 1 0 species for all Europe.
Brainerd and Peitersen (6, 44) worked chiefly in Vermont and else-
where in New England. In their two bulletins on the blackberries of
New England they give an understandable grouping of the wild black-
berries of the eastern United States. The two men made extensive
field surveys, grew the wild forms side by side under cultivation, and
^^^^^^^ made many crosses and many
experiments on the effect of cli-
matic conditions on the different
forms. They describe 12 species
for New England and refer many
of the cultivated varieties to the
species or their hybrids. Exper-
iments in shading parts of plants
showed that leaves of plants in
heavy shade had less than one-
seventieth the number of hairs
and far fewer prickles than leaves
in the sun. Canes in the shade
wore trailing, but those in the
open were erect. The work
showed (1) that the species of
eastern North America and most
hybrids were self-sterile or nearly
self-sterile; (2) that hybrids had
a large percentage of aborted
pollen; and (3) that the hybrids
showed segregation.
Bailey (8, 4, 5) has compiled
much information regarding the
history of both the cultivated and
the wild blackberries and has
made extensive field collections
of both. He has issued a series
of monographs on his interpretation of the wild species and has
described many new forms.
Lidforss's studies (34) on inheritance in European blackberries,
which were published in 1914 after his death, furnish an account of
the development of the wild European blackberries. He obtained
true and false hybrids in crosses and in selfing. The true hybrids
always split in the second generation, while the false hybrids reproduce
the mother exactly. In the false hybrids (1) no seed development
occurs without pollination; but (2) when the flowers are pollinated
false seed develops; (3) this false seed apparently does not develop
from the ovule but from a cell in the wall of the ovary; and (4) the
plants grown from such false seed are just as like the mother plant as if
Figure 3. — B. M. Young, of Morgan City,
La., at about the time he originated the
Young dewberry (Youngberry) over 30
years ago. Mr. Young is still breeding
raspberries and blackberries.
BLACKBERRIES AND RASPBERRIES
303
propagated from a rooted tip or a root cutting. Gustafsson (28) also
studied the development of false hybrids. Some European forms
produce these false seedlings only; others may produce some true and
some false, while others produce all true seedlings. Thus in Oregon
and Washington the Evergreen and Himalaya blackberries usually
reproduce each other exactly from these false seeds, and hundreds of
thousands of wild plants occur that are just as alike as if they had been
propagated by root cuttings or by tip plants (20). Only rarely are
true seedlings of these two varieties found.
B. M. Young, of Morgan City, La. (fig. 3), produced a hybrid
between the Phenomenal (very similar to Logan) and the Mayes
Figure I. — The Young dewberry or trailing blackberry (Youngberry), one of ibe finest*
flavored, largest, and most productive varieties; a cross of Phenomenal X Mayes.
dewberry or trailing blackberry about 1905. It was not introduced
until about 1926, but it has quickly become an important sort (Young
dewberry, or Youngberry, fig. 4), replacing the Logan to a large extent
in California and to some extent in Oregon and Washington . In regions
to which it is adapted it is the finest in flavor of all the blackberry
group. Though Young has done extensive berry work since then,
he has introduced no other variety.
The Logan and Its Relatives
The origin of the Logan is not yet fully explained. As stated
above, in 1881 Judge Logan, at Santa Cruz, Calif., grew seedlings of a
very rank-growing trailmg blackberry, the Aughinbaugh. It was
504
YEARBOOK, 1937
pistillate-flowered, so that the flowers must have been pollinated
either by wild male blackberries nearby, by an eastern erect black-
berry in his garden, or by a red raspberry. Among about 100 seedlings
there was the one later named Logan (fig. 5) with large, deep-red
fruits. Judge Logan assumed that it was a cross of the black-fruited
Aughinbaugh with the red raspberry. In recent years several facts
have thrown doubt on this: (1) Blackberry-raspberry hybrids are
mostly sterile, and if they do fruit they neither pick off like the
blackberry nor pull off like the raspberry, but mash in the hand, while
the Logan picks off like a blackberry. (2) Seedlings of the Logan
terry
western trailing bfackberry.
derived from the
are all red-fruited and pick off like a blackberry. They vary in size,
sweetness, season of ripening, vigor, etc., but show no distinct rasp-
berrylike characters. (3) Cytologically the Logan seems like a pure
species (22). Chromosome pairing is regular and reduction division
is quite normal as for a pure species, not abnormal as in hybrids. It
has 42 chromosomes, while the raspberry has 14. Plants of thespecies
nearest like the Logan have 42 as the most common number. (4)
Many hybrids of the Logan with selections of the wild blackberry
are fertile, while most crosses of the Logan with the raspberry are not.
On the other hand, blackberry-raspberry hybrids resemble the Logan
in habit of growth and to some extent in type of fruit. The red-
fruited wild blackberries of the Pacific coast so far observed are much
lighter red than the Logan. Perfect-flowered self-fertile selections
of the wild observed so far differ considerably from the Logan.
BLACKBERRIES AND RASPBERRIES 505
Further study of the wild blackberries of the West, as grown under
cultivation, and hybrids with the red raspberry and blackberry should
do much to unravel the origin of the Logan. The evidence at hand
indicates that the Logan is most probably a red-fruited sport of the
wild blackberry.
Evolution of the Blackberries of Europe
There are two great centers of wild blackberries, eastern North
America and Europe. According to Focke (25), the European and
American species were separated in comparatively recent time,
geologically speaking, probably by the southern movement of glaciers
in the ice age. He holds that there are some 15 general types with a
few more species to which all European blackberries can be referred.
Sudre (54) came to a similar conclusion. Gustafsson (28, 29), of
Sweden, concluded that when the ice age brought two widely different
species groups together so that they hybridized, many of the pseudo-
gamic blackberries of Europe that come true to seed originated.
Because they came exactly true to seed they could reproduce them-
selves down through hundreds and thousands of years and eventually
became widely distributed. At the present time in Europe there are
thousands of forms of blackberries. Some few are good species;
more are ancient hybrids that are more or less widely distributed;
and many others are pseudogamic forms resulting from hybridizing,
of which Oregon Evergreen and Himalaya are representative in this
country. The Brainerd (28), which originated as a cross of Himalaya
and an American variety, reproduces to some extent by pseudogamy,
though no purely American variety is known to reproduce in this way.
Crane refers to Rubus thyrsiger Banning and Focke, R. nitidioides
Watson, R. .borreri Bell Salt., R. laciniatus Willd. (Evergreen), R.
rusticanus E. Merc, and its variety inermis Willd., R. schlechten-
dahlii Wiehe, R. calvatus Blox. (Edward Langley), and R. procerus
(Himalaya) as being European blackberries of possible value for
breeding, R. thyrsiger and R. nitidioides have very large clusters of
good-sized fruit of excellent flavor. R. borreri is early for a European
blackberry. R. rusticanus is late and small-fruited, but hy-
brids are cultivated varieties. R. inermis is a thornless form of R.
rusticanus. m o t>
Thornless Sports of Blackberries
Productive thornless sports of the Evergreen, Logan, Mammoth, and
Young have been found, propagated, and introduced. Bud sports in
general are considered to be due to the appearance of recessive char-
acters, and this is probably the case with these blackberries. However,
these productive thornless sports are all chimeras, having a thin layer
of thornless tissue overlying thorny. Whenever they are propagated
by root cuttings, or when the canes freeze back so that shoots come up
from below the crown, they are always thorny. Seedlings of the thorn-
less Evergreen raised by the writer, and seedlings of other thornless
sports raised by H. M. Butterfield, of the University of California,
have all been thorny.
Most thornless sports have been unproductive, and thornlessness
may be linked with sterility (19). For a thornless sport to be pro-
ductive the thornless tissue around the outside of the cane apparently
138904°— 37 33 ++
506 YEARBOOK, 1937
should be thick enough to prevent the production of thorns, but not
thick enough to form the tissue that produces flowers and berries. If
the thornless layer is relatively thick so that flowers are produced from
it, then the flowers seem to bo entirely or nearly sterile.
Breeding Work at Experiment Stations
Compared with other berries, little systematic breeding work has
been done with the blackberries. The aims of experiments now under
way probably represent some of the most worth-while objectives.
At the Rhode Island Agricultural Experiment Station the origina-
tion of hardy thornless forms is being studied. The first crosses were
made in 1929. Thornless sorts such as Rubus canadensis, Austin Thorn-
less, Cory, and Thornless Young have been crossed with Snyder,
Eldorado, Alfred, Lucretia, and Gardena.
At the New York (State) station the first crosses were made in
1912, and some have been made from time to time ever since, notably
a considerable number in 1927. Eldorado has been crossed with
Agawam, Rathbun, Joy, Best of AH, Brewer, Buckeye, and Erskine
Park; Erskine Park with Rathbun and Buckeye; Rathbun with
Agawam and Snyder. Agawam has been selfed and crossed with
Snyder; Buckeye with Joy; Mersereau with Snyder. Strawberry
Flavored has been selfed. The Eldorado X Brewer cross is considered
a good one.
At the North Carolina station dewberry breeding began in 1926.
Young and Lucretia were crossed, and the first-generation selections
have been backcrossed in an attempt to obtain productive, disease-
resistant, high-flavored, thornless sorts. The _ Cameron variety has
been selected, propagated, and named for its vigor, high flavor, firm-
ness, thornlessness, and resistance to anthracnose, to septoria leaf spot,
and to nematodes, and D-3 and D-4 for the size of their cluster. In a
cross of Young X Austin Thornless there were 334 thornless and 411
thorny in the first-generation progeny.
At the Texas station breeding work began in 1909. Ness (4-1)
crossed a selection of the southern dewberry, Rubus trivialis, with the
Brilliant red raspberry in 1912. The first and second generations were
quite sterile except for five of the second-generation (open-pollinated)
plants. These gave rise to a third generation, from which selections
were made that were introduced as Nessberry in 1921. The Nessberry
was then backcrossed with the dewberry, two raspberries, and a
blackberry. The resulting progenies have been selfed for two to four
generations.4 The Nessberry is drought-resistant and has high flavor,
but the fruit does not separate from the stem like either a blackberry
or a raspberry. The obtaining of fertile seedlings in the third and
fourth generations indicates that it may be possible through back-
crossing to obtain seedlings the fruit of which will separate either like
a raspberry or like a blackbeny. Other breeding begun by Yarnell in
1934 (57) involves crosses and selfing of Young, Early Harvest, Hall
Lawton, Crandall Early, Early Wonder, Lucretia, Dallas, Haupt, and
Mayes.
*S. II. Yarnell (o7), who has carried on the work in recent years, found that the Nessberry (re=14) has
twice tiie chromosome number of its parents (n=7),and he concluded that its fertility was due to chromosome
doubling. Plants of the F3 of Nessberry («=14) X Hailsham red raspberry (m=7), and plants of the Fj of
Nessberry X Early Harvest blackberry all had the 14 (2«=28) chromosome number and were fertile.
BLACKBERRIES AND RASPBERRIES 507
Breeding Work of the United States Department
of Agriculture
The first crosses in the blackberry-breeding work of the United
States Department of Agriculture were made in gardens in Atlanta,
Ga., in 1919, and the seedlings were raised at Glenn Dale, Md. Only
two seedlings grew to maturity, one of which was named the Brainerd
(fig. 6) (23). It is a cross of Himalaya with an erect garden variety,
prohahly the Georgia Mammoth. The Brainerd is grown coinmrr-
Fiffire 6. — The Brainerd blackberry, .1 cr.>^- of Himalaya on an erect-growing eastern
variety. Note the large clusters of this \ ariely. It is being grown in western Oregon
for shipping and canning.
508 YEARBOOK, 1937
cially at Gresham, Oreg., for canning and shipping, replacing Hima-
laya for that purpose. It was hardy in Maryland until the winters
of 1934-35 and 1935-36, when it was injured by temperatures of — 17°
and —23° F. Later crosses made at Beltsville, Md., and Willard,
N. C, were between cultivated varieties such as Joy, Eldorado,
Jumbo, Mersereau, and Blowers, while Eldorado and Joy were selfed.
Recent crosses have been between Himalaya and Evergreen, Joy,
Snyder, Early Wonder, Austin Thornless, Taylor, Lawton,; and
Eureka. The objective is to combine the size of fruit and hardiness
of eastern varieties with the productiveness and vigor of the Himalaya.
In these crosses a large proportion of the first-generation hybrid
plants are true Himalaya, due to the development of "false" seed-
lings in this variety of the European type. In the crosses of Hima-
laya with American varieties 64 percent were maternal, that is, just
like Himalaya, and 36 percent were true hybrids. In the cross
Himalaya X Thornless Austin, about half of the true seedlings
are thornless.
The breeding work at Corvallis, Oreg., is chiefly directed toward
combining the high flavor of the native trailing blackberry with the
size, firmness, productiveness, and hardiness of commercial varieties.
Selections of different types of the wild blackberry, as well as the
Logan, Young, Ideal Wild, and Zelinski, have been used in crossing
with one another and with Lucretia, Austin Thornless, Eldorado,
Oregon, Evergreen, Himalaya, and Mammoth. Crosses of the
Logan with Mammoth, Lucretia, and Young were mostly sterile (22),
even though they have the same chromosome number. Many selec-
tions have been made from the wild and Logan crosses, some having
the high flavor of the wild, which is considered the highest quality in
all the dewberry -blackberry group. One Himalaya X Logan hybrid
is fully fertile and fairly vigorous, the second generation showing
segregation into an immense number of forms. Out of a population
of 817 hybrids of Logan X Young, 2 very firm-fruited selections have
been made, both having the deep wine-colored fruit of the Young.
Blackberry-Raspberry Hybrids in England
Besides the Nessberry discussed above, several hybrids between
blackberry and raspberry have been raised in England. Among
these are Laxtonberry (Logan X Superlative), Mahdi (Belle de Fonte-
nay X common English blackberry), Veitchberry (November Abun-
dance X common English blackberry), and Kings Acre. The Mahdi
and Kings Acre have 21, Veitchberry has 28, and Laxtonberry 49
chromosomes in vegetative cells. The Veitchberry is the most fertile
and productive. None of these hybrids, however, has proved of
commercial value, though they are of good quality. Just as with
the Nessberry, they do not separate readily from the stem like either
a raspberry or a blackberry. Possibly they will need to be back-
crossed with a raspberry or with a blackberry before seedlings can be
obtained that produce fruit that can be picked readily. Gruber (27)
in Germany is doing some work in crossing blackberries and rasp-
berries to transfer the disease resistance of the blackberry to a
raspberry.
BLACKBERRIES AND RASPBERRIES 509
Some Problems and Objectives of Blackberry Breeders
Among the most important objectives for breeders are hardier
northern varieties, thornlessness, small seed, high flavor, firmness,
and resistance to double blossom and orange rust. Sources of each
of these desirable characters are known and are listed in the appendix.
Thus, both Rubus canadensis, the thornless blackberry, and R. per-
gratus are native in northern regions where most cultivated varieties
are not hardy. Austin Thornless, Burbank Thornless, Cameron, and
R. canadensis are available for breeding thornless varieties. With their
superior flavor, R. pergratus and R. allegheniensis for eastern and
R. macropetalus, R. ursinus, Logan, Young, and Boysen for western
blackberries furnish material for great improvement in dessert quality.
Excepting R. cuneifolia, the most erect blackberries have the smallest
seeds, though a large-fruited and large- but few-seeded trailing variety
like the Young may not be objectionably seedy.
It may be possible to utilize some of the immense-fruited black-
berries of northern South America in breeding (45). They belong to
a very different group from North American blackberries; but it
is possible that hybrids with this group might be large-fruited seedlings
that would reproduce exactly from seed, as do certain European
varieties resulting from wide crosses.
RASPBERRIES
History of the Raspberry
According to Iledrick (81), the first red raspberries were introduced
into cultivation in Europe about 400 years ago. Three hundred
years ago there were at least two varieties cultivated in England, but
variety names were not applied until after 1800. The European
varieties were introduced into the United States even before 1800 and
at first were raised even more extensively than were selections of
native American raspberry. Probably one or more selections of the
American red raspberry were in cultivation by 1800. The first named
black raspberries were probably the Doolittle, introduced by H. H.
Doolittle, Oaks Corners, N. Y., about 1850, and the Ohio Everbearing,
found by Nicholas Longworth, Cincinnati, Ohio, in 1852.
A Dr. Brinkle, of Philadelphia, Pa., was the first successful rasp-
berry breeder of this country. He originated many varieties of
raspberries, among which was the high-flavored Orange (Brinkles
Orange). This he raised from seed in 1845. Although there was a
considerable acreage of raspberries around some of the larger cities,
it was nearly 1870 before the raspberry became a crop of any great
importance. The Cuthbert variety was found as a chance seedling
in 1865 in what is now a part of New York City; it was probably a
cross of Hudson River Antwerp, a European variety, with a wild
native red. Ever since the introduction of the Cuthbert, which is
still the chief variety of the Northwest, the raspberry has been an
important small fruit. Cuthbert and Ranere (St. Regis) are the only
important varieties of red raspberry now grown that originated as
chance seedlings.
Other leading red raspberries are Latham, Chief, Ohta, Marlboro,
and King, all of which resulted from definite attempts to improve the
510 YEARBOOK, 1937
raspberry. The Marlboro was originated b3r A. J. Cay wood, Marl-
boro, N. Y., before 1880, and at one time was the leading variety.
The Latham originated at the Minnesota Fruit Breeding Farm as a
cross between King and Loudon, and was introduced in 1912. Since
then it has become the leading variety cast of the Rocky Mountains.
The Ohta, Chief, June, and Newburgh are other varieties from experi-
ment stations that have succeeded.
The leading black raspberries, Cumberland in the East and Munger
in the Northwest, both resulted from growing seedlings, the Munger
coming from seed of the Shaffer Purple. Quillen, an anthracnose-
resistant variety grown in the Midwest, resulted from a cross between
Cumberland and Hopkins. The other black raspberries grown to any
extent commercially originated as chance seedlings. Recently, how-
ever, the New York (State) Agricultural Experiment Station, at Geneva,
has introduced four black raspberries that seem to be succeeding.
The most important of the purple varieties, Columbian, was grown
from seed of Cuthbert. Recently the Potomac and Sodus purple
varieties have been introduced. Both are succeeding and are adapted
to a wider range of conditions than Columbian. The Potomac is one
of the hardiest of all raspberries.
American and European Rasprerries
The commercial cultivated raspberries of the world have come from
the wild red raspberry of Europe (Bubus idaeus L.) and the red (B.
strigosus Michx.) and black (B. occidentalis L.) wild raspberries of
North America (16).
Bubus idaeus is native in much of Europe, but closely allied forms
occur across northern Asia to Japan. It is much like the North
American red raspberry, but in general is not so hardy and usually
has stout purple prickles, larger leaves, and duller and more conical
berries. The largest size in cultivated berries has come from the
Lloyd George and Pynes Royal varieties, which are derived from this
species.
The American red raspberry, Bubus strigosus, is native in the
mountains from Georgia to Pennsylvania and in both lowlands and
mountains from Maine to the Dakotas, far north in Canada, and west
to British Columbia. Allied forms occur in the Rocky Mountains.
It has much greater hardiness than the European species, the canes
are more slender and often more erect, the prickles are not so stout
and sometimes are absent. The berries are seldom thimble-shaped
and are usually bright red. The species is extremely variable in the
wild.
The American black raspberry, Bubus occidentalis, has much the
same range in the United States as B. strigosus, but ranges as far south
as Oklahoma, Atlanta, Ga., and the lowlands of Virginia. It is not so
hardy as the. wild red raspberry, and although found from North
Dakota and Quebec to Maine and New Brunswick, is far less common
than the red raspberry toward its northern limit. A closely allied
species, B. leucodermis Dougl., occurs from British Columbia to
California.
The black raspberry has a sweeter but a more seedy fruit than the
red. Curiously, though, yellow- or amber-fruited black raspberries
BLACKBERRIES AND RASPBERRIES 511
are common, and yellow and amber colors are common in the red
raspberries of Europe, these colors are rarely found in American wild
red raspberries. Natural hybrids between the black and the red,
called purple raspberries, occur quite commonly in some sections.
The purple raspberries are more vigorous and if fertile are more pro-
ductive than either the red or black. The fruit is often larger and
usually has more pulp or flesh in proportion to the seed.
Related berries that are often called raspberries are the two flower-
ing raspberries of the woods, Rubus odoratus L. and R. parvijlorus
Nutt., with large, showy, purplish-red and white flowers and soft,
thin-fleshed berries ; the salmonberry , R. spedabilis Pursh, a perennial-
caned tender species of the Pacific coast with large berries not in
clusters; and the baked-apple berry, R. chaemaemorus L., of the bogs
of northern Canada, Alaska, northern Europe, and Asia.
Future Raspberries
Three other raspberries are grown slightly in some parts of the world
— the Andes black raspberry (Rubus glaucus Benth.) in northern South
America; R. niveus Thunb. (R. lasiocarpus Sm.) in northern India
and Burma; and the wineberry (R. phoenicolasius Maxim.), intro-
duced from Japan, in the northeastern United States. Besides these
6 kinds, the Van Fleet, grown to some extent in the Southern States,
is a cross of Cuthbert and R. kuntzeanus Hemsl., a Chinese raspberry
The possibilities of improving the raspberry by utilizing just these
seven species are enormous. The very large size of the varieties now
in cultivation in Europe, such as Lloyd George, Pynes Royal, and the
new Imperial, as well as of Marcy and many recent selections at the
Geneva, Corvallis, and Puyallup stations, would hardly have been
thought possible 10 years ago. Some of the qualities to be combined
in raspberries of the future are the firmness of the Newburgh, U. S.
D. A. No. 9 (Latham X Ranere), and Potomac; the vigor of Van Fleet;
the productiveness of plants of Dixie and Van Fleet; the immense
fruit clusters of Rubus kuntzeanus (fig. 7); the resistance to cold of
Ohta, Sunbeam, Latham, Chief, Potomac, and Sarah and some other
Canadian varieties; the resistance of Van Fleet and Quillen seedlings
to anthracnose; of Lloyd George and Newburgh to mosaic-carrying
aphis, and of Cuthbert to verticillium wilt.
The cultivated raspberries, however, are but a small part of the
raspberries of the world. Focke {25), in his latest book on the sub-
ject of raspberries, published some 20 years ago, described 195 wild
kinds of eastern and southern Asia alone. These range from whole
groups with vines and leaves much like those of the grape to others
with leaves like the hawthorn, bamboo, viburnum, maple, and apple.
Some have soft, others woody stems. Some are low plants, while
Rubus ellipticus Sm., the Golden Evergreen raspberry, may have canes
3 inches in diameter and grow 14 feet high (fig. 8). Eastern Asia is
the center of the wild raspberries of the world.
Some of the species of Asia and elsewhere are already being crossed.
The Hawaiian station and the Armstrong nurseries are working with
several forms of the Akala raspberry of Hawaii. Crosses have been
made between both Rubus biflorus Buch., a Chinese species, and the
Figure 7. — Rubus kuntzeanus, a very large-clustered, vigorous species of raspberry from
Asia, with red, wine, and black fruit. The Van Fleet resulted from a cross between
this species and Cuthbert,
BLACKBERRIES AND RASPBERRIES 513
salmonberry, R. spectabilis, and red-raspberry varieties at the Cor-
vallis station. At the Willard and Beltsville stations and at the
Tennessee station R. kuntzeanus of Asia and the Van Fleet are being
used. At the United States Horticultural Field Station, Cheyenne,
Wyo., R. deliciosus Torr. of the Kocky Mountains is being crossed
with red raspberries. At the Beltsville and Willard stations there
are about 2,000 crosses of R. parvifolius L. (fig. 9), an Asiatic trailing
raspberry, with red, black, and purple varieties. R. niveus has been
used by B. M. Young, of Morgan City, La., and at the Beltsville
Figure 8. — A single plant of the Golden Evergreen raspberry, Rubus ellipticus, 14
feet high and 26 feet across. Some of the canes were 3 inches in diameter. (Watson-
ville, Calif.)
station. William E. Whitehouse, of the Department, has succeeded
recently in introducing several other species, and they are now avail-
able to breeders. The woolly raspberry, R. lasiostylus Focke (fig. 10),
is a very large-fruited species from Asia. All the raspberry species
so far studied have seven chromosomes in the reproductive cells, as
have most cultivated varieties. Raspberry species so far tried in
breeding have crossed readily, though many of the seedlings have not
been fertile. Some of these species that have superior germ plasm of
value are: For size of fruit, Akala and R. biflorus; for vigor of plant,
Golden Evergreen (R. ellipticus) and R. biflorus; for resistance to
disease, R. biflorus, R. ellipticus, R. coreanusMiq. (fig. 11), the Andes
berry (R. glaucus), R. kuntzeanus, R. innominatus Moore. Most of
the breeding work with raspberries lies ahead.
Raspberries and Blackberries of Unusual Colors
In the raspberry there are yellow- or golden- and apricot- or amber-
colored berries as well as black, red, purple, and various shades of
color from red to purple and purple to black. The yellow and apricot
514
YEARBOOK, 1937
colors are found in seedlings of the European red and in varieties
derived in part from the European, such as Cuthbert and Herbert,
but never, so far as known, from the American red. In black rasp-
berries, the yellow form is common in the wild, especially in Maryland.
Figure 9. — Riibus parvi/ulius, the trailing raspberry of Japan ami eastern China, which
is very disease-resistant in the United States. Selections of this species are promising
in southern States, and hybrids with red, black, and purple varieties are being fruited.
The introduced species of raspberries from Asia have a great variety
of colors, ranging tlirough red, orange, yellow, lavender, purple, and
wine color to black.
In the blackberry, the white or pale yellow is rather commonly
found in the wild in many and possibly all species in North America
as well as in many species in Europe. Pink selections have been seen
in Alabama and in Oregon, while lavender-colored ones have been
reported in North Carolina. In the West the wild blackberry often
is not quite black but a very deep wane color.
Raspberry Breeding at State Stations
At the New York (State) Agricultural Experiment Station (50, 51,
56) at Geneva, the first crosses were made in 1892, and the work has
been continued to the present. Over 250 different crosses have been
made and over 15,000 seedlings raised. Of these crosses 130 were of
BLACKBERRIES AND RASPBERRIES
515
red raspberries, 27 were of black raspberries, and 93 were with or for
purple raspberries. For the breeding work the station maintains a
collection of some 38 species of raspberries and blackberries, 33 varieties
of red raspberries, 18 of black raspberries, and 7 purple varieties.
Figure 10. — Rubus lasiostylus, a very large -fruited species from Asia, the fruit of which
is covered with a thick mat of hair. The upper fruit is ripe. (Natural size.)
There still are 41 station selections under test for possible introduction.
Besides many commercial varieties, 55 of their own selections have
been used in the breeding work, as well as the named varieties that
have been introduced by the New York station.
Of the red raspberries, George L. Slate, who has had charge of the
berry breeding for many years, states that Lloyd George, Newman,
Herbert, and Loudon have been exceptional parents. Cuthbert has not
been so good a parent, though it has transmitted its high flavor and
canning quality in some crosses. Erskine Park, Buckeye, Count,
Douboro, Empire, Owasco, Syracuse, Gold Drop, Ohta, Ranere, Su-
perlative, Newman 20, and Marldon have been poor parents in the
crosses made. Selfed populations resulted in dwarfs, weaklings, a high
proportion of seedlings lacking hardiness, and a considerable amount
of partial and complete sterility. Establishment of inbred lines has
not been made a part of the breeding program because of (1) the long
516
YEARBOOK, 1937
time between generations, (2) the high proportion of the weaklings,
dwarfs, and otherwise inferior seedlings, and (3) the difficulty of
maintaining a number of inbred lines because of virus diseases,
winter injury, and lack of vigor. Slate states: "The vast possibilities
of improving raspberries by variety crossing make this method the
Figure II. — Ruhus <orr<miis. an Asiatic lil.irk rMllllHII 1' rr-i-lanl to leaf and cane
diseases that is promising for breeding for Southern Siates.
most promising line of attack in red raspberry improvement at this
station."
Many hybrids, backcrosses, and selfed seedlings have been raised
involving crosses with blackberries. Among these crosses are:
Mahdi X Herbert
(Mahdi X Herbert) X (Newman X Her-
bert)
(Mahdi X Herbert) X Herbert
(Mahdi X Herbert) X Lloyd George
Mahdi X Phenomenal
Mahdi X Lucretia
Mahdi X Mcrsereau
Mahdi X (Mahdi X Lucretia)
Mahdi X Rubus odor at us
( Mahdi X Herbert) nlfed
(Mahdi X Lucretia) selfed
(Mahdi X Lucretia) X Herbert
( Mahdi X Lucretia) X Snyder
Herbert X Logan
Cuthbert X Logan
Latham X Logan
Donburo X Logan
(Herbert X Logan) selfed
Rubus phoenicolasius X Agawam
R. phoenicolasius X Empire
(R. phoenicolasius X Empire) selfed
(R. phoenicolasius X Empire) X Empire
Smith No. 1 (black raspberry) X Snyder
Kansas X Agawam
Kansas X Mayes
Mammoth X Agawam
Mammoth X Cuthbert
Mammoth X Herbert
Mammoth X Snyder
Tims, the Mahdi, a raspberry X blackberry cross, has been back-
crossed with both the raspberry and the blackberry, and the progeny
BLACKBERRIES AND RASPBERRIES
517
I ifiiirv 12. — A hybrid seedling with a desirable fruiting habit.
which makes picking easy.
Note exposed fruit.
backcrossed a second time with each. So far no selections have been
introduced.
Thirty-four different crosses between the black and the red rasp-
berries, 19 different selfings, some 21 different backcrosses with red,
and 19 second backcrosses with red have been made. Over 4,300
seedlings have been raised (fig. 12), and 3 varieties have been intro-
518 YEARBOOK, 1937
duced, of which Brant and Sodus are first crosses and Webster is a
backcross of a black and a purple. Backcrossing is still considered
promising in this group. Typical red and black raspberries have not
appeared when the hybrids were selfed or when purples have been
crossed with purples. Dundee X Newburgh has been considered
one of the most promising crosses. Besides hybrid vigor, drought
resistance has been noted in the purple raspberries.
With the black raspberry, emphasis has been placed on size, color,
firmness, and quality of berry, and vigor, yield, and hardiness of
plant. Cumberland, Dundee, Eureka, Farmer, Grant, Gregg, Hil-
born, Honeysweet, Kansas, Lane, Palmer, Rachel, Smith No. 1,
and Watson Prolific have been used in crosses.
At the South Dakota station (80) many thousands of seedling
raspberries have been grown, particularly crosses of cultivated vari-
eties with selections of the wild red raspberry that have proved fully
hardy at Brookings, with no winter protection. Sunbeam and Ohta
(Flaming Giant) are two of the eight named selections resulting
from the crosses that have proved to be adapted to the climatic
conditions of eastern South Dakota.
At the Illinois station raspberry breeding (jf, 2, 8, 9, 10) was begun
in 1922 and over 14,000 seedlings are now under test. Some 121
selections have been made for further observations. The Quillen,
Farmer, Older, Munger, and Pearl black varieties and Latham,
June, Starlight, Newburgh, Ulster, and Taylor red sorts have been
used in this work. Among the best crosses for purple varieties
are Qiullen X June, Quillen X Latham, and Quillen X Newburgh.
In a study of the inheritance of anthracnose resistance, 52 percent of
the selfed seedlings of Quillen were free from anthracnose, and no
selfed seedlings of Cumberland, Pearl, Farmer, Honeysweet, Older,
Munger, Boyal Purple, Earheart, or Conratn were free. Of 661
Quillen selfed, 622 had reddish-brown canes and 34 yellow canes.
Of 105 Pearl selfed, 96 had reddish-brown canes and 9 yellow, close
to a 15:1 ratio. When Cumberland was selfed, all 452 seedlings had
reddish-brown canes.
At the Washington State station at Puyallup raspberry breeding
was first begun in 1909 (S3). No varieties were introduced from the
early work. In 1928 new breeding work was begun to obtain varieties
hardier than Cuthbert, which would be satisfactory for canning,
freezing, and shipping, and resistant to mosaic. Selections of Cuth-
bert and Lloyd George parentage are especially promising. Inheri-
tance of fruit characters and of winter hardiness has been made an
important part of the study (48, 49).
At the Minnesota station the breeding work has been notable for
the origination of Latham and Chief red raspberries, the Latham
being the leading red variety of the eastern United States. It is
estimated that at the present time there are about 25,000 acres of
Latham and 3,000 acres of Chief grown. The work is being continued,
and mauy black and red selections are now being tested. Among the
principal varieties crossed are Latham, Chief, Herbert, Ranere, King,
Lloyd George, Cuthbert, selections of the wild, and the Farmer and
Piatt black varieties. The Farmer and Piatt black and the Chief red
varieties have been inbred. E. Angelo, in charge of the work at
BLACKBERRIES AND RASPBERRIES 519
present, emphasizes the need for studies on the mode of inheritance
of characters, breeding for disease resistance, and improving the
flavor of the fruit.
Extensive breeding work began at the Tennessee station in 1931,
using the Van Fleet for its disease resistance and vigor in the South, to
cross with red varieties. Selections have been made and are being
At the North Carolina station breeding was begun in 1926 to obtain
varieties resistant to diseases and adapted to the South, by using
Asiatic species, especially Rubus Ujlorus. One variety, Dixie, is
being introduced in 1936-37. Although not large-fruited, it is one
of the most productive of red raspberries and is desirable for home
use. Beginning in 1936, the work was made cooperative with the
Department.
Raspberry Breeding
at United States Department of Agriculture Stations
The first raspberry breeding of the United States Department of
Agriculture was done by W- Van Fleet while he was at the United
States Plant Introduction Garden at Chico, Calif., in 1909 (17). He
crossed Rubus kuntzeanus, a species from China, with the Cuthbert, and
from the seedlings selected one that was later named the Van Fleet.
The writer became associated with Dr. Van Fleet at the Department's
station at Glenn Dale, Md., in 1920 and has carried on the breeding
work since. The Potomac (purple) is the only variety introduced
besides Van Fleet. The work at Beltsville, Md., and Willard, N . C.,
consists largely of (1) genetic studies, (2). hybridizing foreign species
with cultivated varieties, and (3) crossing to obtain resistance to leal
spot, anthracnose, and leaf rust (18, 21). At Willard, in cooperation
with the North Carolina Agricultural Experiment Station, varieties
adapted to the South are being bred, using foreign species in the crosses.
At Corvallis, Oreg., in cooperation with the Oregon station, a large
part of the work is directed toward obtaining large-fruited varieties
suitable for canning, freezing, and long-distance shipment. Inher-
itance of resistance to diseases is being studied in cooperation with the
small-fruit pathologists. Red varieties used in crossing include
Antwerp, Cayuga, Chief, Cuthbert, Herbert, Latham, Lloyd George,
Newburgh, Ranere, and Viking; black varieties, Cumberland, Munger,
and Farmer; and the purple variety, Potomac. Species used include
Rubus spectabilis, the salmonberry, R. leucodermis, the western black
raspberry, and several Asiatic species. Lloyd George X Newburgh
crosses have been particularly promising, selections from these having
larger fruit than any yet found.
At Cheyenne, Wyo., crosses are being made with the entirely hardy
perennial-caned Rubus deliciosus in the attempt to obtain much greater
hardiness. Raspberry Breeding Abroad
Canada
Raspberry breeding was begun in Canada at Ottawa as early as
1873 (88), when William Saunders (47), later Director of the Experi-
mental Farm at Ottawa, crossed the Doolittle (black) wrth the
Philadelphia (dark red— a probable black X red hybrid) and obtamed
520 YEARBOOK, 193 7
24 purple-fruited seedlings. His work was transferred in 1887 to the
Dominion station when he entered the Dominion service, and it has
been continued since. At least 23 varieties have been introduced, of
which 2, Brighton and Count, are still important varieties in Canada.
Raspberry breeding began at Vineland, Ontario, in 1913 (43).
According to W. J. Strong, in charge of the work at present, some 125
crosses and 167 open and self-pollinations, using 16 varieties, resulted
in 21,000 seedlings. About 140 selections were propagated, and one
variety 2 the Viking, was named and introduced. This variety, intro-
duced in 1924, is extensively grown in Ontario and is increasing
slowly in importance in other sections in Canada and the northern
United States. It is estimated that 1,500 acres of this variety are
" England
In England (52, 58), extensive work in breeding raspberries by N-
H. Grubb (26) at East Mailing, Kent, has included selfing 19 varieties
to study the, inheritance of. characters. Of 74 selfed seedlings of
Pynes Royal, 22 were worthy of propagation, and of 92 selfed Lloyd
George, 17 were propagated. Pynes Royal seedlings were much larger,
but were mostly dark, hard to pick, and not of high flavor. Lloyd
George seedlings produced many canes, but few had large fruit.
Red Cross and Preussen, selfed, were very disappointing. Of 4 selec-
tions chosen for trial, all were from self -pollinated progenies of
Royal X Lloyd George hybrids.
Chief emphasis has been placed by M. B. Crane and W. J. C.
Lawrence (11, 14, 15), of John Innes Institute, Merton, on inheritance
of characters such as sex, color of prickles and fruit, and hairiness.
Two pairs of factors were found to determine sex, two color, and one
■ Private Breeders of Raspberries
Several private breeders have valuable varieties to their credit,
especially C. P. Newman, of La Salle, Quebec, Canada, and George
Pyne, of Topsham, Devon, England. Newman (42) originated the
Newman from seed of several varieties mixed. This variety is out-
outstanding for its firmness of fruit, hardiness of cane, and mosaic
resistance. It was introduced in 1919 and is still grown commercially.
It is important as one of the parents of the Newburgh, Monroe, Taylor,
Marcy, and Potomac raspberries.
Pyne selected Devon and Pynes Royal from self-sown seedlings and
Park Lane and Red Cross from self-sown seedlings that he transplanted
and tested. Mayfair came from seed of Park Lane, and Imperial
from seed of Royal. Better-Late is a seedling of a blackberry-
raspberry hybrid. The Red Cross is notable as an early productive
sort with a long season, Park Lane and Mayfair for their high flavor,
Pynes Royal for its large size, excellent flavor, and firmness, while
Imperial is reported to be larger than Pynes Royal, which has been
the largest raspberry known.
A third private breeder, George Adams, of Smithville, Ontario, has
grown seedlings over a period of some 40 years, starting with purple
and black varieties. His Adams 87 and Adams 101 are grown to a
considerable extent in western New York. Adams 101 is a red variety
rooting at the tips of canes, while Adams 87 is an especially hardy sort.
BLACKBERRIES AND RASPBERRIES
521
Generic CROSSES
Hybrids between raspberries and blackberries have been discussed
above and the reported hybrids with the strawberry arc discussed in
the article on strawberry breeding in this yearbook. Hybrids of
raspberries or blackberries with roses, apples, etc., have been reported,
but no authentic cases are known. Van Fleet once stated that he
had tried to cross the raspberry and a rugosa rose (Rosa rugosa
Thunb.). He obtained sterile
seedlings, which may possibly
have been hybrids.
Everbearing or Fall-Fruiting
Raspbi:uiui:s
The so-called everbearing rasp-
berries produce a crop in the
early summer at the same time as
other varieties and later a second
crop on the new canes. The
Ranere (St. Regis) is the most
common American red variety of
this group. Erskine and La
France are two others, and the
Xew York (State) station has
just introduced another, Indian
Summer. These varieties form
fruit buds on the most vigorous
canes in midsummer, beginning
at the tips and flowering and
fruiting downward toward the
base. Besides these, other vari-
eties like the Lloyd George in
Oregon and Washington begin to
flower and fruit in September.
Even some of the ordinary vari-
eties such as Cuthbert may start
flowering in September in some
years. In the wild, fall-fruiting
raspberries are often found.
Figure 13. — A, Red-raspberry buds and
How crs. The hint at the lower left is
ready to cross, or in warm, dry weather il
may be so far advanced that pollen is al-
ready shedding. The oilier flowers are
loo advanced In n.- • out of doors. /.'.
After emasculating with scalpel, forceps,
or the thumbnail, pollen is applied direct-
ly by twirling the flower so that the pollen
is brushed from the anthers to the pistils.
C, Blackberry flower with pistils in reoep*
tive condition and with some of the an-
thers on the outer stamens already split
open and shedding pollen.
188804
::i
522
YEARBOOK, 1937
Summer- and fall-fruiting black raspberries are also rather commonly
found in the wild, and several have been introduced. The Ohio
Everbearing was one of the first black raspberries ever named and
cultivated. However, fall-fruiting black raspberries are not very
practicable, for fruiting on the tips of the canes interferes with propa-
gation. So far, only with special care have they succeeded. Purple
summer- and fall-fruiting raspberries present the same difficulties
as do the blacks.
TECHNIQUE OF BLACKBERRY AND
RASPBERRY CROSSING
Most of the breeding work with blackberries and raspberries is
done out of doors, though when tender varieties are to be used it may
be done with potted or tubbed plants in the greenhouse. Flowers of
Figure 14. — Flower clusters bagged after crossing, to protect from bees.
all except self-sterile kinds should be emasculated at least 1 day before
the calyx begins to split, because in some varieties under certain
conditions the anthers may open and shed pollen before the buds
open (fig. 13). The thumbnail is commonly used to cut away the
calyx, corolla, and anthers, and the operation does not seem to injure
the setting of the flowers. In the field the flower clusters should be
covered with ordinary paper bags to keep insects away (lig. 14).
After 1 to several days the pistils are receptive and pollen is applied.
Pollen may be gathered in a dish and applied with a small, soft brush,
or a flower may be twirled between the fingers so that the pollen is
brushed from the stamens onto the pistils of the flowers used as the
female parent. The paper bags may be taken off the flower clusters
BLACKBERRIES AND RASPBERRIES 523
after the third day, or, in all except the windiest or rainiest weather,
they may be left on to protect the clusters until the berries ripen.
The seed of the ripe berries may be cleaned or the berries crushed in
dry sand. Though dried seed of some varieties and species may
germinate if given suitable conditions, they are likely to require 2 or
more years. For this reason, in the work of the Department the
fresh seed is planted immediately, and the flats or pots of seed are
stored in a cool, moist place and are exposed the following winter to
2 or more months of cold weather just above freezing. The soil in
the flats is kept moist from sowing until germination. Good germi-
nation has followed this practice. Fresh seed of tropical species gener-
ally germinates at once. Occasionally seed of some raspberry
varieties has also germinated immediately after planting. Under
favorable conditions the seedlings can be set in the field in the spring,
and by the following year many kinds may fruit.
LITERATURE CITED
(1) Anthony, R. D.
1916. SOME NOTES ON THE BREEDING OP RASPBERRIES. N. Y. Agr. Expt;
Sta. Bull. 417: 75-88.
(2)
1916. SOME RESULTS IN THE BREEDING OP SMALL FRUITS. Amer. SoC.
Hort. Sci. Proc. 12: 121-125.
(3) Bailey, L. H.
1932. north American blackbeiiries. Gentes Herbarum 2: 271-423.
(4)
1933. blackberries of the lower south. Gentes Ttcrbarum 3: 119-
148.
(5)
1934. certain northern blackberries. Gentes Herbarum 3: 247-271.
(6) Brainerd, E., and Peitersen, A. K.
1920. blackberries of new England — their classification. Vt.
Agr. Expt. Sta. Bull. 217, 84 pp., illus.
(7) Chomiruhy, N.
1927. beitrao zur keimfaiiigkeit und zytologie DBS pollens einiger
prunus und rubussorte.v. Angew. Bot. 9: 626-636.
(8) Colby, A. S.
1928. the inheritance of anthkacnose resistance. Jour. Heredity
19: 327-382.
(9)
(10)
1933. horticultural investigations. III. Agr. Expt. Sta. Rept. for
1932-33, pp. 240-241.
1936. THE inheritance of suckering and tip layering in purple
raspberry seedlings. Amer. Soc. Hort. Sci. Proc. 33 (1935) :
427-429.
(11) Crane, M. B.
1936. blackberries, hybrid berries, and autumn-fruiting rasp-
berries. Roy. Hort, Soc. : 121-128.
(12) and Darlington, C. D.
1927. the origin of new forms in rubus, i. Genctica 9: 241-278.
(13) and Darlington, C. D.
1932. chromatid segregation in tetraploid rubus. Nature 129: 869.
(14) and Lawrence, W. J. C.
1930. studies ix sterility. Intern. Hort. Cong. 9: 100-116.
(15) — and Lawrence, \V. J. C.
1931. inheritance of sex, colour, and hairiness i\t the raspberry,
rubus idaeus l. Jour. Genetics 24: 243-255, ap. 1931, no. 2.
(16) Darrow, G. M.
1920. ARE OUR RASPBERRIES DERIVED FROM AMERICAN OR EUROPEAN
species? Jour. Heredity 11: 179-184.
524 YEARBOOK, 1937
(17) Harrow, G. M.
1924. THE VAN FLEET RASPBERRY, A SEW HI'JJRID VARIETY. U. S. Dept.
Agr. Cir. 320: 1-13.
(18)
1928. NOTES ON THORNLESS BLACKBERRIES. Til Hill CHROMOSOME NUM-
BER and their breeding. Jour. Heredity 19: 139-142.
1931. EUROPEAN BLACKBERRY SEEDLINCS AND HYBRIDS IV TUB PACIFIC
northwest. Jour. Heredity 22 (5) : 143-140.
1935. susceptibility of raspberry species and varieties to leaf
SPOT (mYCOSPHAEHELLA RUBl) AT BELTSVILLB, MARYLAND.
Phytopathology 25: 961-962.
1933. CYTOLOGY AND BREEDING OF RTJBUS MACROPETALUS, TUB LOGAN,
and related blackberries. Jour. Agr. Research 27: 315-330.
1926. RASPBERRY BREEDING EXPERIMENTS, HYBRIDS AND HACK CROSSES
between red and black varieties. Jour. Heredity 17: 339-
348.
(19)
(20) -
(21) -
(22) -
(23) -
1932. the brainerd blackberry. U. S. Dept. Agr. Cir. 220, 4 pp., illus.
(24) Detjbn, L. R.
1916. self-ste hility in dewberries and blackberries. N. C. Agr.
Expt. Sta. Tech. Bull. 11: 5-37.
(25) Focke, W. O.
1910-14. SPECIES RUBORUM. MONOGRAPHIAE GENERIS HUB! PltODROMUS.
3 v., illus. Stuttgart.
(26) Grubb, N. H.
1935. RASPBERRY BREEDING AT EAST MALLING, 1922-34. Jour. Polllol.
and Hort. Sci. 13 (2) : 108-134.
(27) Gruber, P.
1932. beerenobstzuchtung. Zuchter4: 237-242.
(28) Gustafsson, A.
1930. KASTRIEltUNGEN UND PSEUDOGAMIE BEI RTJBUS. Bot. Notiser 6:
477-494.
(29) .
1933. chromosome numbers in the genus rubus. Hereditas 18 : 77-80.
(30) Hansen, N. E., and Haralson, C.
1907. RASPBERRIES, BLACKBERRIES, AND DEWBERRIES. S. Dak. Agr.
Expt. Sta. Bull. 104: 268-297.
(31) Hedrick, U. P., asst. by Howe, G. H., Taylor, O. M., Bergkr, A., Slate,
G. L., and Einset, O.
1935. the small fruits of new york. N. Y. State Dept. Farms and
Markets Ann. Rept. 33, pt. 2, 614 pp., illus.
(32) Hoar, C. S.
1916. sterility as a result of hybridization and the condition of
pollen in rubus. Bot. Gaz. 62: 370-388.
(33) Lawrence, W. H.
1912. plant breeding. Wash. Agr. Expt. Sta. Bull. 7: 115-118.
(34) Lidforss, B.
1914. resume seiner arbeiten t}BER rubus. Ztsohr.-Induktivc Ab-
stanim. u. Vererbungslehre 12: 1-13.
(35) Longley, A. E.
1924. cytological studies in the genus rubus. Amer. Jour. Bot. 11:
249-282.
(36)
1927. relationship of polyploidy to pollen sterility in the genera
rubus and fragaria. Mem. Hort. Soc. N. Y. 3: 15-17.
BLACKBERRIES AND RASPBERRIES 525
Longley, A. E. and D arrow, G. M.
1924. OYTOLOGICAL studies of diploid and POLYPLOID FORMS in hasp-
berries. Jour. Agr. Research 27: 737-748.
Macotjn, W. T.
1923. report op the dominion HORTICULTURIST. Canada Expt. Farms,
Div. Hort., Rept. 1922: 12.
MlCHURIN, I. V.
1934. [REVIEW OF 60 YEARS' WORK IN BREEDING NEW VARIETIES OF
fruits.] 366 [2] pp., illus. Moskva. [In Russian.] 3d ed.
[the raspberry tekhas— "texas"], pp. 313-314; [THE "abundant"
BLACKBERRY-], pp. 315-316.
Morris, H. F.
1933. A STUDY OF BLACKBERRY" AND DEWBERRY VARIETIES AS BREEDING
material. Amer. Soc. Hort. Sci. Proe. 30 (1933): 117-121.
Ness, H.
1925. BREEDING EXPERIMENTS WITH BLACKBERRIES AND RASPBERRIES.
Texas Agr. Expt. Sta. Bull. 326: 1-28.
Newman, C. P.
1916, SOME RESULTS IN RAISING NEW RASPBERRIES. Aim. Rept. Pomol.
and Fruit Growing Soc, Quebec, pp. 114-121.
Palmer, E. F., and Strong, W. J.
1927. a note on raspberry breeding. Scientific Agr. 7: 387.
Peitersen, A. K.
1921. blackberries of new England— genetic status of the plants
Vt. Agr. Expt, Sta. Bull. 218, 34 pp., illus.
POPENOE, W.
1920. THE COLOMBIAN BERRY OR GIANT BLACKBERRY OP COLOMBIA. Jour
Heredity 11: 195-203.
Rozanova, M. A.
1934. modes of form genesis in the genus rcbus. Bot. Zhurn
USSR 19: 376-384. no. 4.
Saunders, W.
1894. NOTES ON EXPERIMENTS IN CROSS FERTILIZATION. Trans. Roy.
Soc. Canada.
Schwartze, C. D.
1933. THE GENETIC CONSTITUTION OF CERTAIN RED RASPBERRY VARIETIES
IN RELATION TO THEIR BREEDING BEHAVIOR. PrOC. Amer. SoC
Hort, Sci. 30 (1933): 113-116.
1934. FURTHER OBSERVATIONS UPON THE LLOYD GEORGE RED RASPBERRY
as A parent in breeding. Proc. Amer. Soc. Hort. Sci. 31:
411-415.
Slate, G. L.
1933. THE BEST PARENTS IN PURPLE RASPBERRY BREEDING. PrOC. Amer.
Soc. Hort, Sci. 30: 108-112.
1934. THE BEST PARENTS IN RED RASPBERRY BREEDING. Amer. SoC.
Hort. Sci. Proc. 31: 407-410.
Spinks, G. T.
1925. progress report on fruit breeding. Ann. Rept. Agr. and
Hort. Sta. Univ. Bristol, pp. 38-39.
1932. progress report on fruit breeding. Ann. Rept. Agr. and Hort.
Res. Sta., Univ. Bristol, pp. 19-23.
Sudre, H.
1908-13. RUBI EUROPAE VEL MONOGRAPHIA ICONIBUS 1LLUSTRATA RUBO-
rum. fasc. 1-6, illus. Paris.
Thayer, P.
1923. raspberry breeding notes. Jour. Heredity 14: 12-13.
Wellington, R.
1913. raspberry' BREEDING. Amer. Soc. Hort. Sci. Proc. 90: 155-159.
Yarnell, S. H.
1936. chromosome behavior in blackberry-raspberry HYBRIDS.
Jour. Agr. Research 52: 385-396.
526 YEARBOOK, 1937
APPENDIX
Table 1. — Breeding work with blackberries at experiment stations
Location
Tast workers
Present workers
Year
begun
Objectives
State stations:
Georgia, Experiment...
New Jersey, New
Brunswick.
New York, Qeneva
North Carolina, Ral-
eigh.
South Dakota, Brook-
ings.
Rhode Island, King-
ston
Texas, College Station..
Washington, Puyallup.
Department stations:
Maryland, Beltsville
(formerly at Qlenn
Dale).
North Carolina, Wil-
lard.
Oregon, Corvallis
Canada:
Ontario, Lennoxville...
British Columbia, Sid-
ney.
England:
Long Ashton, Bristol-
John Innes Institute,
Merton (IB, IS).
Union of Soviet Socialist
Republics:
Michurin Institute (89,
J. G. Woodroof..
J. E. Bailey, H. L.
Cochran, H. P.
Stuckey.
J.H.Clark
George L. Slate, R.
Wellington.
C. F. Williams
N. E. Hansen,
Charles Haralson.
H. Ness
W. H. Lawrence, J.
L. Stahl.
W. Van Fleet, G. F.
Waldo.
G.F.Waldo
C. E. Schuster, B.
S. Pickett, George
M. Darrow.
A. E. Stene, T. E.
Odland.
S. H. Yarnell, H. F.
Morris.
George II. Darrow...
George M. Darrow, C.
F. Williams.
G.F.Waldo
W. O. Baekhouse.
I. V. Michurin.
J. G. Maynard, a. T.
Spinks.
M. B. Crane, C. D.
Darlington.
A. Petrov, V.
Lithovitzer.
1927
1928
1912
1920
1929
1908
1909
1920
1929
1928
High-flavored southern
varieties.
Productive, disease-re-
sistant sorts.
Hardy, productive sorts.
Thornless, high-flavored,
disease-resistant, hardy
sorts.
Hardy varieties.
Thornlessness.
Drought-resistant, high-
flavored, productive
hybrids.
Crosses of Evergreen and
American varieties.
Thornless productive
Himalaya hybrids, Lo-
gan X eastern black-
berry hybrids.
Do.
Thornless, firm, high-
flavored hybrids of Lo-
gan, Himalaya, Ever-
green, Eldorado, and
selections of the wild.
Table and canning vari-
eties.
Genetics and thornless-
ness.
Hardiness.
Table 2. — Blackberry varieties originated by public agencies
Location
Variety
Year
intro-
duced
Parentage
Superior qualities
State stations:
North Carolina, Ral-
1936-
1937
1930
1921
1932
Young X Lucretia
Seedling of wild from
Siberia.
Rubus triviatis X Bril-
liant raspberry.
Himalaya X erect east-
ern variety.
R. rusticanus inermisX
R. thrytlger.
eigh.
South Dakota,
less, high flavor.
Brookings.
Texas, College Sta-
tion.
Department stations:
sistance.
(formerly at Glenn
Dale).
England:
Large, late, long seasons.
Large, bright, produc-
tive.
Merton.
1932
Union of Soviet Social-
ist Republics:
Seedling of Lucretia
(39).
BLACKBERRIES AND RASPBERRIES
Table 3. — Blackberry varieties originated by private agencies
527
Name and location
Variety
Year
intro-
duced
Parentage Superior qualities
i
1020
1034
Phenomenal X Mayes.- _
Veitchberry seedling
City, La.
Laxton Bros,, Bedford,
England.
Bedford Giant — __
lent flavor, large.
Early for European type
large.
Source of Superior Qualities ijn Blackberries
Plant Characters
Hardy against cold. Rubus pergratns, R. canadensis, R. alleghe/densis, Snyder,
Eldorado, Ancient Briton, Agawam.
Resistant to orange rust. Eldorado, Oregon Evergreen (Black Diamond),
Russell, Snyder.
Resistant to double blossom. Himalaya, Rogers, Advance (may be same as
Rogers).
Resistant to root nematode. Hall Lawton, Young, Crandall.
Resistant to crown gall. Austin Thornless, Advance.
Resistant to leaf spot (septoria) . Young, Himalaya, Evergreen, Boysen, Early
Harvest.
Resistant to anthracnose. Young, Boysen.
Resistant to vertieillium wilt. Himalaya and Evergreen, immune; Logan and
Mammoth, resistant.
Thornless (genetically thornless). Austin Thornless, R. canadensis, Burbauk
Thornless, Cameron.
Vigorous. Himalaya, Evergreen, Brainerd, Logan, R. macropetalus, R. ursinus,
Young, Boysen; Haupt in Texas, Eldorado in North.
Resistant to drought. Nessberry.
Large flower clusters. R. thyrsiger, R. nilidioides, Himalaya, Evergreen.
Fruit Characters
Early ripening. Advance and Rogers (earliest), McDonald, Haupt, Lucretia,
Young, Mayes, Early Harvest, Wilson Early; R. borreri of Europe.
Late ripening. Burbank Thornless, Himalaya, Evergreen, Brainerd, R.
cuneifolia, Nanticoke, Eureka; R. ruslicanus of Europe.
Firm. Oregon (Logan X Young) , Advance, Evergreen; Mersercau of eastern
blackberries.
Large. Boysen, Young, Mammoth, Logan, Eldorado, and Brewer.
Do not turn red in shipment. — Brainerd.
Canning. Evergreen in Oregon and Washington; Brainerd, Young, Boysen,
Logan, Ideal Wild.
Freezing. Young, Boysen, Cameron, Logan.
Excellent flavor. Ideal Wild, Zelinski, Young, Boysen, Logau, R. macropetalus
of western type; Cameron, Eldorado, Brewer, R. allegheniensix, R. pergratus.
Small seed. Early Harvest.
Lack of seediness. Young, Boysen.
Table 4. — Breeding tvork ivith raspberries at experiment stations
Location
Pas! workers
Present workers
It. V. Lott.
Slate stations:
Arkansas, Fayette-
ville.
Colorado, Love-land..
Connecticut, New
IJ a v-en.
Georgia, Experiment. J. G. Woodroof-
See footnotes at end of (able.
I.E. Vaile.
D. F. Jones, W. R.
Singleton.
II. L. Cochran, II. P.
Stuckey, J. E.
Bailey.
Year
begun
0)
1930
1927
Objectives
(Work transferred to
Cheyenne, Wyo., 1836.)
Value of inbreeding.
Southern variety of high
flavor.
528 YEARBOOK, 1937
Table 1. — Breeding ivork with raspberries at experiment stations — Continued
Location
Past workers
Present workers
Year
begun
Objectives
State stations— Contd.
W. T. Pope
1036
1922
Crosses with native rasp-
berries.
C. J. Alexopoulus
A. S. Colby
ance, high flavor, pro-
ductiveness.
R. M. Bailey
1932
1934
18912
1892
1926
1920
A. P. French
\V. H. Alderman, E.
Angelo, F.E.Haral-
son.
George L. Slate, H.
Wellington.
C. F. Williams
A. F. Yeager, D. H.
Scott.
Isolation of pure lines for
later work.
Hardiness.
Disease resistance, fall
fruiting, size of fruit,
quality, productive-
ness.
Obtaining hybrids with
Asiatic species for
South.
herst.
Minnesota, Excelsior.
New York, Geneva . .
North Carolina, Ra-
Charles Haralson, M.
J. Dorscy, J. H.
Beaumont, S. B.
Green.
S. A. Beach, 0. M.
Taylor, W. H. Al-
derman, R. D. An-
thony, M.J. Dorsey.
leigh.
North Dakota, Fargo.
Ohio, Wooster.-
P.Thayer (66)
Genetics of yellow color.
South Carolina,
W.J.Young _..
Clemson College.
South Dakota,
Charles Haralson
J. A. McClintock
M. B. Hardy, J. L.
Stahl, W. H. Law-
rence.
1898
1931
1909 «
1935
1920
1929
1928
1873'
Brookings.
Bottor varieties through
use of Van Fleet and
Rubus kuntzeanns.
Hardiness, mosaic resist
ance, adaptation to
canning, freezing, and
dessert.
Resistance to cold and
drought. Crossing R.
dtliciosus.
Disease resistance, hy-
brids with species, ge-
netic studies.
Do.
Large - fruited, hardy,
canning, and freezing
varieties, hybrids with
species.
Hardiness.
ville.
Washington, Puyal-
lup.
Department stations:
Wyoming, Chey-
C. D. Schwartze
LeRoy Powers
George M. Darrow
George M. Darrow, C.
F. Williams (coop-
erate of North Car-
olina station).
G. F. Waldo
enne.
Maryland, Beltsville.
North Carolina, Wil-
lard.
Oregon, Corvallis...
G.F.Waldo „...
do -
C. E. Schuster, B. S.
Pickett, G.L.Rygg,
G. M . Darrow.
William Saunders, W.
T. Macoun, A. J.
Logsdail, John
Craig.
Canada:
M. B. Davis, W.
Hunter.
Agassiz, British Co-
lumbia.
Vineland, Ontario
England:
LongAshton, Bristol .
East Mailing, Kent._
F. S. Reeves _.
W. J. Strong, E. F.
Palmer.
J. G. Maynard, G. T.
Spinks.
N. H. Grubb
1913
Disease - resistant, can-
ning, large varieties,
earliness, hardiness,
yield, high flavor.
Table and canning va-
rieties.
Disease resistance.
Blackberry-raspberry ge-
netics.
High flavor with suckers.
Merton, John Innes
CD. Darlington, M.
B. Crane, W. J. C.
Lawrence, Faberge.
C. G. Dahl
1920
1930
1930
Horticultural In-
stitute.
Sweden: Alnarp
Norway: Njos, Her-
P. Stedje
mansvcrk.
Switzerland: Wadens-
wil Experiment Sta-
tion.
1 Recently.
Or earlier.
s About.
* Official since 1887.
BLACKBERRIES AND RASPBERRIES
Table 5. — Raspberry varieties originated by public agencies
529
Year
Location
Variety
intro-
duced
Parentage
Superior qualities
State stations:
Alaska, Sitka
Bensonborry . . .
1920
Cuthbert X Salmon-
berry.
Perennial canes, suckers,
light-yellow fruit.
Minnesota, St. Paul.
1914
Hardy, productive, large,
attractive, late, Arm.
Chief. .
1930
Cold-resistant, high flavor,
early, productive, vigor-
ous, bright red.
North Carolina,
1936-
Raleigh.
37
ant.
P-117
1935
(Latham X Farmer) F2--
Cold-, drought-, and red-
spider resistant, purple.
New "i ork, Geneva. _
Red:
Donboro ...
1908
Loudon X Marlboro
Bright red.
Louboro
1908
do
Marlative
1908
Marlboro X Superlative-
Attractive.
Marldon
1908
Marlboro X Loudon
June. .- ...
1909
Loudon X Marlboro
Bright red, very early, pro-
ductive. '
Ontario ...
1918
N. Y. 94 (Superlative X
Loudon) selfed.
Very early, bright, produc-
tive.
Cayuga.. .. . .
1922
June X Cuthbert...
Earlier, firmer, brighter
than Cuthbert.
Owasco
1922
do
Large, high flavor.
1922
do
Late, high flavor.
Very large, firm, produc-
Newburgh
1929
Newman X Herbert
tive, mosaic-escaping.
Monroe..
1932
Newman X Cuthbert. ..
Midseason, firm, good.
Ulster .
1933
Early, largo, productive.
Large, late, firm, bright-
Taylor
1935
Newman x Lloyd George
red, high flavor.
Indian Summer.
1938
1950 (Empire X Herbert)
X Lloyd George.
Lloyd George X New-
Fall fruiting, large.
Marcy
103fi
Very large, good flavor,
man.
mosaic-escaping.
Black:
Dundee ....
1927
Smith No. 1 X Palmer. .
Large, attractive, high
flavor.
1931
Bristol
1934
Watson Prolific X Hon-
eysweet.
Early, firm, high flavor.
1935
....do
Early, attractive, high
flavor.
Purple:
Brant ..
1926
Smith No. 1 X June
Large, firm, attractive.
1928
Firm, productive.
purple.
Sodus .
1935
Dundee X Newburgh..
Firm, large, productive,
attractive.
South Dakota, Brook-
Sunbeam... ... .
190T>
Shaffer X Cavalier wild.
Hardv.
ings.
Ohta
J 91 2
Cavalier wild X Minne-
tonka.
1922
Few prickles, firm.
mils wild.
Moonbeam.
1922
(Cavalier wild X Black
Hills wild) X Shaffer.
Late, firm.
Smoothcane ... .
1922
Black Hills wild X
Minnetonka.
Firm, thornless.
1922
No prickles,
right, large.
Starlight
1922
Cavalier wild X Minne-
tonka.
Seedling of wild or hy-
brid with cultivated.
Twilight
1922
r.ight red.
U. S. D. A. station:
Maryland, Glenn
1924
Vigorous, disease-resistant,
hardy in South.
Dale.
Cuthbert.
Potomac _.
1932
Farmer X Newman
Disease-resistant (resistant
to streak virus), purple,
Canada:
hardy, jam and canning.
Ottawa
1880
Philadelphia X McCor-
mick.
Sarah. _
1893
Seedling of Shaffer.
Suckers, very late, firm,
high flavor.
Carleton .
1894
Seedling of Biggar
Early.
1894
Purple, suckers.
Early, vigorous, large,
bright-red, firm.
Count
1894
530 YEARBOOK, 1937
Table 5. — Raspberry varieties originated by public agencies — Continued
Location
Variety
Year
intro-
duced
Parentage
Superior qualities
Canada— Continued.
1894
1894
1894
1894
1894
1394
1894
1894
1894
1894
1894
1900
1900
1900
1900
1900
1900
1900
1924
1905 1
Unknown.. -
Gregg X Cuthbert—
Seedling of Biggar ... .
late, vigorous, firm.
Garfield _
Seedling of Philadelphia.
Seedling of Biggar _
Purple, suckers, late, vigor-
ous.
Yellow.
Lady Ann ...
Muriel _ ._
Seedling of Biggar .
YS'lAa.'.'.'.'.'.'.'.' '.'.'".
Vigorous, early.
Early, firm, vigorous.
Early, bright-red.
Late, firm, vigorous.
Trusty... ... .
Early, hardy, productive.
Shinn.. ._
Firm, productive.
Gregg X Cuthbert
Cuthbert X Marlboro..
Seedling of Logan. ...
early.
Purple, firm.
Vigorous, high flavor, pro-
ductive firm.
Hardy, tip-rooting.
Vincland, Ontario
Union of Soviet Social-
ist Republics:
Michurin Institute...
Viking
Teklias .
Productivnaia.
i Selected.
Table 6. — Private raspberry breeders
Name and location
Varieties
Year
intro-
duced
Cross
Desirable qualities
United States:
strong Nurseries, On-
tario, Calif.
H. Eockhill, Conrad,
Iowa.
H. M. Butterflold,
3 being propa-
gated.
Latham X Older
Purple, hardy, firm.
Berkeley, Calif.
A. C. Dike, Bristol,
Dike
1933
1919
191S
June X Latham. .
From mixed seed of Her-
bert, King, Loudon,
Cuthbert, and Eaton.
Seedling of Eaton. ... .
Vt.
Canada:
to mosaic.
La Salle, Quebec.
George Adams, Smith-
ville, Ontario.
Newman 20
mosaic-resistant.
Large, late, firm.
not turn dark.
Firm, propagates by tip-
rooting.
England:
Bountiful
1917
1922
1925
1925
1935
1904
1913
1917
1922
1929
1931
1935
Abundance X Superla-
tive.
Yellow Hammer. .
Reward.. .. .. .
George Pyne, Topham,
Devon.
Pynes Roval . . .
Seedling raised in 1907...
docs not turn dark.
Largest English, sweet.
Tart, large, early,
nigh flavor.
Do.
Jam variety, very late.
Larger than Royal, coni-
Park Lano -
Mayfair
Better-Late
do
Seedling of Park Lane. _ .
Blackberry-raspberry X
raspberry.
Seedling of Royal
cal, very vigorous, pro-
ductive.
BLACKBERRIES AND RASPBERRIES 531
Source of Superior Qualities in Raspberries
Plant Characters
Hardy against cold. Ohta, Latham, Chief, Potomac (purple), Sarah, Starlight,
Sunbeam, Newman, Adams 87, Ncwburgh, King, London, N. Y. 3024 (June X
Brighton), P 117 (Latham X Farmer F3 of North Dakota), Heath (black), Tckhas
(in Russia).
Resistant to heat. Van Fleet, Dixie, Rancrc.
Resistant to drought. Sodus, Latham, Marey.
Resistant to leaf spot. Van Fleet, Ranere,' U. S. D. A. No. 9 (Latham X
Ranere), Dixie, Potomac, Evans; Pynes Royal and Baths Perfection (in England) ;
Rubus_ biflorus, R. innominatus, R. inopertus, R. kuntzeanus, R. parvifolius, R.
phoenicolasius.
Resistant to anthracnose. Van Fleet, Rubus coreanus, R. kuntzeanus, R.
biflorus, R. innominatus, R. niveus, North Carolina R-14, Quillen and Naples
(black) , Potomac (purple) , Rancrc.
Resistant to yellow rust {Phragmidium rubi-idaei). Black raspberries (Rubus
oecidentalis and R. leucodermis) immune; highly resistant reds arc Lloyd George,
Owasco, Seneca, Antwerp, Ranere (not in California), Cayuga, Herbert, Chief.
Resistant to leaf rust (late raspberry rust). Hailshairi red; all black rasp-
berries are very resistant.
Resistant to spur blight. Columbian, Newman, and Marcy red show some
resistance; probably all black varieties are resistant.
Resistant to streak. Potomac and all red varieties.
Immune to leaf curl. All purples and Farmer and New Logan blacks.
Resistant to green mottled mosaic. Latham, Chief, Ranere.
Escaping green mottled mosaic. Lloyd George, Herbert, Newman, Marcy,
Indian Summer, Ranere, Potomac.
Resistant to mosaic in England. MacLarcn, Baumforth A, Red Antwerp B.
Resistant to crown gall. Surprise (of California) .
Resistant to vcrticillium wilt. Syracuse, Cuthbert, Ohta, Antwerp, Marlboro,
Cayuga, Owasco, Seneca; Superlative and Black Antwerp A (in Europe); Rubus
biflorus.
Resistant to aphid (Amphorophora rubi). Lloyd George, Herbert, Ncwburgh,
Newman.
Everbearing. Ranere, La France, Erskin Park (summer bearing), Lloyd
George (fall fruiting in the Northwest), Indian Summer, Hailsham (in England),
November Abundance.
Fruit Characters
Early ripening. U. S. D. A. No. 0 (Latham X Ranere), Ranere, June, Chief
Ohta, Marlboro", N. Y. 3024, Red Cross (in England) ; black varieties, Shuttle-
worth, Kansas, Bristol, Evans.
Late ripening. Van Fleet, Latham, Newman, Taylor, Cuthbert, N. Y. 3041;
black variety, Rachel.
Firm. Potomac, Newman, U. S. D. A. No. 9 (Latham X Ranere), Newburgh,
Latham, Ranere (in California) ; Baumforth seedling B, Burnett Holm, Penville
Champion, and Pynes Royal (in England).
Large. Imperial, Pynes Royal, Lloyd George, Preusscn (in England); Marcy,
Newburgh, Tavlor, Latham; Sodus (purple); Bristol, Dundee, and Cumberland
(black).
Preserving. Cuthbert, Potomac, Columbian, Lloyd George.
Canning. Washington No. 89 (Cuthbert X Lloyd George) ; Cuthbert, Poto-
mac, Royal, Sodus (purple).
Freezing. Latham, Chief, Viking (in the East); Washington No. 16, Lloyd
George, Cuthbert, Viking, and Newburgh (in the West).
Small seed. Van Fleet, Llovd George.
Bright red. U. S. D. A. No" 9 (Latham X Ranere), Washington No. 76 (Lloyd
George X Cuthbert), Ohta, Ranere, Chief, June, Newman, Taylor, Adams 87, and
Latham; Newburgh (in Oregon); Preussen (in England).
Do not turn dark. IT. S. D. A. No. 9. Newourgh, Taylor, Viking, June,
Adams 87; in England, Burnett Holm, Northward, Preussen, Baumforth B,
Hornet A.
532
YEARBOOK, 1937
Excellent flavor. Cuthbert, Viking, Cayuga, Chief, Taylor; black varieties,
Bristol, Evans, Honeyswect, Cumberland; in England, Norwich Wonder A,
Preussen, Baumforth B, Hornet A, Pynes Royal, Park Lane.
Productiveness. Latham, Viking, Newburgh, June, Taylor, Marcy, and
Bristol (reds); Cumberland (black); Potomac and Sodus (purple); in England,
Lloyd George and Baumforth A.
Somatic Chromosome Numbers in Rubus
[See literature citations 7, 12, 22, 28, 29, 32, 3$, SO, 37. An asterisk (*) after a name indicates an unpublished
record of A. R. J.ongley]
l.j. somatic chromosomes
Blackberries:
European:
72. rusticanus E. Merc.
R. rusticanus inermis Willd.
R. tomentosus Borkh.
R. ulmifolius Schott.
Burbank Thornless (R. inermis
Willd.).
American:
R. allegheniensis Porter.*
R. argutus Link.
R. canadensis L.
R. setosus Bigel.
Ancient Briton.*
Crystal White.*
Eureka (R. cuneifolia Pursh).*
Haupt.*
Jordan.*
Maxwell.*
McDonald.*
Pink.*
Raspberries:
R. adenophorus Rolfe.
R. coreanus Miq.
R. idaeus L. (European red).
R. illecebrosus Focke (strawberry-
raspberry) .
R. kuntzeanus Hemsl.
R. lasiostylus Focke.
R. leucodermis Dougl. (western black-
cap).
R. mesogaeus Focke.
R. occidentalis L. (eastern blackcap).
R. odoratus L. (eastern flowering
raspberry) .
R. parviflorus Nutt. (western flower-
ing raspberry) .
R. phoenicolasius Maxim, (wineberry).
R. spectabilis Pursh (salmonberry).
R. strigosus Michx. (American red
raspberry) .
R. triphyllus Thunb.
R. xanthocarpus Bur. and Franch.
Cardinal (purple).
Cumberland (black).
Cuthbert (rod).
Eaton (red).
Gregg (black).
King (red).
Lloyd George (European red).
Newman (red).
Queen Alexandra.
14 somatic chromosomes — Continued
Raspberries — Continued.
Ran ere (red).
Royal (purple).
Superlative (European red).
SI somatic chromosome*
Blackberries (American) :
Marvel (Florida Marvel).
13 wild forms of New England, prob-
ably hybrids.
12 wild forms of Maryland and
District of Columbia, also probably
hybrids.*
Raspberries:
All Summer.
Belle de Fontenay.
Erskine.
Mervcillc Rouge.
November Abundance.
White Queen.
Blackberry -raspberry hybrids:
Kings Acre.*
Mahtii.
28 somatic chromosomes
Blackberries:
European:
R. acuminaius Lindeb.
R. affinis Weihe and Nees.
R. arrhenii J. Lange.
R. bloxamii Lees.
R. caesius L.
R. calvatus Blox.
R. cletrophilus P. J. Muell.
R. corylifolius Sm.*
R. genevieri P. J. Muell.
R. hirtus Waldst. and Kit.
R. imbricatus Hort.
R. incurvatus Bab.
R. insularis Aresch.
R. kaltenbachii Metsch.
R. lindleyanas Lees.
R. nemorosus Arrh.
R. nitidioides Watson.
R. nitidus subsp. opacus Focke.
R. pallidas Weihe and Nees.
R. plicatus Weihe and Nees.
R. polyanthemMS Lindeb.
R. radula Weihe.
R. radula var. anguslifolia Lund.
R. schlechtendalii Weihe.
R. sprengelii Weihe.
BLACKBERRIES AND RASPBERRIES
533
28 somatic chromosomes — Continued
Blackberries — Continued.
European — Continued.
R. strivultus f . Kullensis.
B. suberectus G. Anders.
R. thyrsiger Banning and Focke.
R, villicaulis Koebl.
Edward Langley.
Evergreen or Cut-Leafed.
Himalaya (R. procerus P. J. Muell.).
John Innes.
Pollard.*
Sherlock Jr.*
American:
Two wild forms of Maryland, prob-
ably hybrids.*
Badger.*
Brainerd.
Early Wonder.*
Eldorado.*
Johnson.*
Joy.*
Jumbo.*
La Grange.*
Lawton.*
Mcrsereau.*
Miller.*
Nanticokc (B. curveifolius Pursh).*
Queen.*
Snyder.*
Taylor.*
Texas Everbearing.*
Ward.*
Raspberries:
Hailsham.
La France.
Mervcille Rouge.
Merveille de Quatre Saisons.
Surpassc Merveille a blane.
Blackberry-raspberry hybrid:
Veitchberry.
85 somatic chromosomes
Blackberries:
European:
R. bellardi Weihe and Nees.
American:
Two wild forms of Maryland, prob-
ably hybrids.*
Two wild forms of New England,
probably hybrids.*
Logan seedling.
Logan X Mammoth seedling.
1$ somatic chromosomes
Blackberries:
European:
R. borreri Bell Salt.
R. ciliatus Lindeb.
R. divergens Neum.
"R. insulariformis"-R. wahlbergii
Arrh.
R. niiens Lindeb.
R. iiliaceus Licbm.
Bedford Giant.
American:
Five wild forms of New England,
probably hybrids.
R. loganobaccus Bailey.
Logan (Loganberry).
Corv.*
Erie.*
Lucrctia.
Mammoth.
Phenomenal.
Rathbun .
4-5 somatic chromosomes
Blackberries (European):
R. ehixatus var. subnilidus Lidf.
/f9 somatic chromosomes
Hybrid blackberries (European):
Laxtonberry.
R. lagerbergii Lindeb. var. ballicus
Aresch.
f>6 somatic chromosomes
Dewberries (American):
One wild form of Massachusetts.
Austin Thornless.
Ideal Wild.
Premo.*
Windom.*
Form close to R. loganobaccus Bailey.
70 somatic chromosomes
Form close to R. loganobaccus Bailey.
84 somatic chromosomes
R. macropelalus Dough, of Oregon and
Washington.
IMPROVEMENT OF
CURRANTS AND GOOSEBERRIES
GEORGE M. DARROW, Senior Pomol-
ogist, Division of Fruit and Vegetable Crops
and Diseases, Bureau of Plant Industry
V^URRANTS and gooseberries are closely related bush fruits that
are far more extensively raised and prized in Europe than in the
United States. They were formerly grouped into a single genus,
Ribes, but now the gooseberries are generally placed in a separate
genus, Grossularia. Though hybrids have been made between cur-
rants and gooseberries, only sterile seedlings have so far been raised.
MATERIAL FOR CURRANT BREEDING
The red currant seems to have been cultivated first some time before
1600 in the Netherlands, Denmark, and around the Baltic Sea. Ac-
cording to Hedrick,1 in 1665 Rea mentioned three red currant varieties,
one white, and one small black. Currant bushes were ordered for
the Massachusetts colony in 1629; thus they were early brought to
North America. By 1826 about 20 cultivated varieties were known
in England, a good many of which were brought to the United States
soon after their introduction. Most of the currant industry was
based on European varieties until about 1890. Fay, a seedling
raised by L. Fay, Portland, N. Y., in 1868, was introduced in 1880;
Wilder, a seedling of Versailles, was raised by E. Y. Teas, Irvington,
Ind., about 1877; Red Cross and Diploma both originated from a
cross between Cherry and White Grape made in 1885 by J. Moore,
Attica, N. Y. ; and Perfection originated in 1887 from a cross of Fay X
White Grape made by C. G. Hooker, Rochester, N. Y. These five
varieties quickly became important and constitute possibly 85 percent
of the total present acreage. London Market and Victoria, the other
principal varieties, are old European sorts. Thus the currant indus-
try in the United States is based largely on varieties originated by
American breeders.
The European black currant is extensively cultivated in Europe and
to a lesser extent in Canada, but it has been found to be by far the
most susceptible host for the white-pine blister rust fungus, and the
United States Department of Agriculture advises against its cultiva-
tion in States where white pines are important forest trees.
The American black currant (fig. 1) is a much less susceptible
alternate host for the blister rust fungus than the European black
currant. Though cultivated as a garden crop, there is probably very
little commercial acreage of this fruit. The best-known variety is the
i Uedhick, U. P., assisted by Howe, G. II., Taylor, O. II., Bekger, A., Slate, G. L., and Einset, O.
TJIB SMALL fruits OF NEW York. 614 pp., illus. Albany. (NT. Y. (State) Dept. Farms and Markets
Ann. Kept. (1924-25) 33, pt. 2.)
534
CURRANTS AND GOOSEBERRIES
535
Crandall, which has large berries. It grows well in the prairie regions
with hot summers, but its berries ripen so unevenly that they must
be picked singly. N. E. Hansen selected and introduced four Ameri-
can black varieties — the Tonah, Atta, Mato, and Wanka — in 1925.
These bear fruit of larger size than the ordinary wild black currant.
In 1923 Thayer's work on the red and the white currant was
published.2 This aided greatly in identifying varieties and classifying
Figure 1. — The American golden or black citrranl. An extremely hardy and drought-
rcsislant native currant that is a much less receptive host of the white-pine blister
rust than the European black currant.
them as to their botanical origin. In 1924 Berger 3 covered species and
varieties of both currants and gooseberries, and his work is very
helpful in studying the group. Hedrick and his associates4 also
described the species and varieties and gave colored plates of many of
the more important types.
Relation of Currants and Gooseberries to
White-Pine Blister Rust
After the white-pine blister rust epidemic had shown this disease to
be a serious menace to white pines in the United States, eradication
of currants and gooseberries, the alternate hosts of the blister rust
» Thayer, P. the red and white currants. Ohio Agr. Expt. Sta. Bull. 371, pp. 307-391, illus. 1923.
» Berger, A. A taxonomic review or currants and gooseberries. N. Y. Agr. Expt. Sta. Tecli.
Bull. 109, 118 pp., illus. 1924. „ _ .
« Hedrick, U. P., assisted by Howe, O. H., Taylor, O. M., Bebger, A., Slate, O. L., and Einset,
O. See footnote 1.
536 YEARBOOK, 1937
fungus, was xmdertaken in sections where the white pine is important.
This has restricted interest in both currants and gooseberries, and in
large areas, as in New England, most of the cultivated currants and
gooseberries have been eradicated. As a consequence, the acreage of
currants in the United States reported for 1929 by the 1930 census,
3,574 acres, was less than half of the 7,379 acres reported in 1919.
Only 1,302 acres of gooseberries were reported in 1929.
The white-pine blister rust was brought into the United States
between 1898 and 1910 on white-pine planting stock imported from
Europe. It is now established throughout most white-pine regions
of the United States from Maine to Virginia, west to Minnesota,
and in Montana, Idaho, Oregon, and Washington. Eecently it has
been found in northwestern California. It injures all species of the
white-pine group (five-needle pines), which are among the most
valuable timber trees of the northern United States, having an
estimated stumpage value of about $400,000,000. The disease can-
not spread from pine to pine, but only from pine to currant and
gooseberry and then from these back to pine. It causes a rust on
the leaves of currant and gooseberry, which may defoliate the most
susceptible varieties.
Valuable white-pine forests can be protected by eradicating wild
and cultivated gooseberries and currants for a distance of about 900
feet around white pines, except that black currants must be destroyed
for greater distances from pines.
Currants and gooseberries differ greatly in their susceptibility to
the white pine blister rust. As already noted, the common culti-
vated black currant — the European black currant (Bibes nigrum L.) —
because of its high susceptibility has been the chief agency in the
rapid and long-distance spread of the disease throughout the Northern
States. The American black currant (B. americanum Mill.), the
golden currants (B. odoratum Wendl. and B. aureum Pursh), and the
native gooseberries (Grossularia divarieata (Dougl.) Spach and G.
curvata (Small) Cov. and Britton) have seemed somewhat more sus-
AMERIGAN native species of gooseberries range from Florida
far north into Canada, and some of them are resistant to high sum-
mer temperatures and to the leaf diseases that have discouraged
gooseberry growing in this country. By suitable crossing, these
characteristics can be combined with the great size, the fine flavor,
and the beauty of varieties developed in Europe through generations
of breeding, encouraged by a public that had a great fondness for
this fruit. Some of the hybrids already produced in this country
show what can be done in the way of improved quality and size of
fruit and vigor of plant. There is no doubt that the gooseberry
offers opportunities for the development of improved varieties that
would be welcome additions to our gardens.
CURRANTS AND GOOSEBERRIES 537
ceptible than most cultivated varieties. Franco-German, Nether-
lands, and London Market currants are very resistant or nearly
immune, while cultivated varieties of gooseberries are very resistant.
To protect white-pine stands, many States have established regu-
lations governing the planting of currants and gooseberries, and some
for white pines. In general, currant aud gooseberry plantings are
prohibited where white pine is important, and white-pine plantings
where the currants and goosebenies are important. Before planting
these fruits the State laws should be consulted. Summaries of the
laws are given in Farmers' Bulletin 1398.5
G. G. Hahn, of the Division of Forest Pathology, Bureau of Plant
Industry, has recently tested the Viking red currant, a variety intro-
duced from Norway, and found it immune to blister rust. Propa-
gating stock has been imported, and in 1935 and 1936 a large number
of plants were distributed to experiment stations for testing as to its
horticultural value and for breeding. Plants already fruiting in New
England and New York have shown that it is of good dessert quality
and desirable for jelly making. A few open-pollinated Viking seed-
lings, produced where cross-pollination was not eliminated, have
been slightly susceptible to blister rust. The culture of the Viking in
white-pine areas will depend on the policy within each State after its
horticultural value and seedling susceptibility to the fungus have been
fully determined. „ „
J Species of Currants
Berger states that there are about 150 species of currants and goose-
berries distributed all over the Northern Hemisphere, but mostly in
North America, and extending along the mountains of the Americas
as far south as Patagonia. At least 100 species are currants and some
50 are gooseberries. The Kocky Mountains in North America are
especially rich in species. There are about 15 species of red currants,
of which Ribes sativum Reichenb., R. rubrum L., R. warscewiczii Jancz.,
and R. petraeum Wulfen, and hybrids of them are considered important
for breeders.
Ribes sativum. — A native of western Europe, frequently escaped from cultivation
in North America. Leaves heart-shaped at base, five-lobed and with lobes
spreading to the side, clusters 10- 20-flowercd, flowers flat, greenish yellow.
Chautauqua, Diploma, Red Cross, Versailles, and Wilder are typical varieties,
while Cherry and Fay belong to a section of the species.
Ribes rubrum. — Northern Europe to northern east Asia. This species is more
northern than R. sativum, from which it is most easily distinguished by its forward-
pointing leaves and cup-shaped flowers. Leaves truncate or subcordate at base
and lobes cupped or pointing forward, broader than long, clusters longer, flowers
cup-shaped, pale green or brownish. London Market and Victoria are typical
varieties. Perfection is derived from R. rubrum X R- sativum.
Ribes warscewiczii. — A very productive species of eastern Siberia, worthy of
use in breeding. Leaves large, heart-shaped; clusters about 15-fiowered, flowers
coppery red to pale flesh-colored; fruit large, blackish purple, very acid. Near
to R. rubrum, but flowers larger and fruit more acid.
Ribes petraeum. — Very widely distributed over Europe, northwestern Africa,
and northern Asia. Leaves roundish, pubescent when young; flowers bell-shaped,
green streaked with red or purple; fruit red or blackish red, more acid than
R. sativum or R. rubrum. Growth starts late in spring. Prince Albert is derived
from R. petraeum X R. rubrum, and Gondouin from R. petraeum X R. sativum.
«Dakkow, G. M., and Detwiler, S. B. currants and gooseberries; their culture and relation
TO white-pine blister rust. U. S. Dept. Agr. Fanners' Bull. 1398, 38 pp., Mas. 1024.
138004°— 37 35 ++
538 YEARBOOK, 1937
The black currants of Europe are all derived from Bibes nigrum.
It is more vigorous than the red currant species, and the whole plant
has a characteristic aroma. To many the fruit flavor is objectionable;
to others highly pleasing. It is a native of Europe as far north as
Scandinavia, and of northern and central Asia. An allied species,
B. ussuriense Jane, is native to eastern Manchuria, but the plant has
a camphorous aroma and the fruit has no odor. The American black
currant, B. americanum, has an aroma in the plant and fruit similar to
that of B. nigrum. It ranges from New Mexico to Virginia northward
into Canada. One variety, Sweet Fruited Missouri, has been in
cultivation, though the fruit is sometimes gathered in the wild. It is
not especially promising.
The golden currants, native in central and northwestern United
States to northern Mexico, are often known as American black
currants. Yellow- or golden-fruited forms are common. The most
common variety is the Crandall, with rather large fruit. There are
several species, but all are close to Bibes odoratum, to which the
Crandall belongs.
There are many ornamental species of currants in the Rocky
Mountain region, but they are mostly of little value for their fruit.
MATERIAL FOR GOOSEBERRY BREEDING
The gooseberry seems to have come into cultivation at about the
same time as the currant. According to Hedrick, it was grown in
English gardens before 1600. By 1629 there were 3 red varieties, a
blue, and a green variety described; by 1778, 24 varieties were de-
scribed; by 1825, 185 kinds were listed; and in 1831 a list of 722
varieties was published. The great development in the size of the
European gooseberry was in part due to the high esteem in which
it is held in England, and to the shows held there. For example, 171
gooseberry shows were held in England in 1845. Prizes were given
for the heaviest fruits, and in 1852 a berry of the London variety was
shown that weighed 7 grams (about one-fourth ounce), or seven to
eight times the weight of the wild fruit.
In North America the European gooseberries were attacked by
mildew., and gooseberries were little grown until after the Houghton
was originated from seed planted in 1833 by A. Houghton, Lynn,
Mass. Houghton was from a cross of the European with an American
variety, and from seed of it Charles Downing, Newburgh, N. Y.,
raised the Downing about 1855 (fig. 2, C). The gooseberry industry
of the United States was largely based on these two varieties until
about 1900, or until after the use of fungicides became common so
that mildew could be controlled on varieties from Europe or of
European parentage, such as Chautauqua and Industry. Since 1900
several varieties have become prominent: Oregon (Oregon Champion),
a cross between Crown Bob and Houghton, raised about 1860 by
P. Prettyman in Oregon ; Pearl, a cross of Downing X Red Warrington,
originated by William Saunders, London, Ontario, and introduced in
1888; Red Jacket (Houghton X Red Warrington), also originated by
Saunders and introduced about 1890; Carrie, a seedling of Houghton,
raised by W. Elliot, Minneapolis, Minn., and introduced in 1905;
CURRANTS AND GOOSEBERRIES
539
Poorman, a seedling raised by W. H. Craighead, Brigham, Utah, and
introduced in 1896; and Como (Pearl X Columbus), originated at the
Minnesota Agricultural Experiment Station and introduced in 1922.
Of these varieties, Poorman (fig. 2, B) has the best appearance and
Figure 2. — A, Columbus, a large European gooseberry; B, Poorman gooseberry, tbe
largest of the hybrids between American and European varieties; C, Downing, a
hybrid that has long been the most important American gooseberry.
is excellent in quality, comparing favorably with the best European
sorts. Though considered a cross between Downing and Houghton,
it may possibly have been a cross with one of the Rocky Mountain
species.
540 YEARBOOK, 1937
Species of Gooseberries
The gooseberries of Europe are derived from the one species Grossu-
laria reclin-ata (L.) Mill., which ranges from northern Africa through
Europe from Spain to the Caucasus, north to Scandinavia. G. uva-
crispa (L.) Mill., a native of central Europe, is said to be more drought-
resistant, with very sweet late fruits. It starts growth about 2 weeks
later than the species. Berger considers that the Houghton was
derived from a cross of this form of the European gooseberry with
G. hirtella. Most of the rest of the species of gooseberries are natives
of North America, and several arc promising for breeders.
Orossularia cynosbali (L.) Mill. — Native from North Carolina to Missouri,
north to Manitoba and New Brunswick, Berry prickly, wine red, with a rather
thick skin. Bush to 4.5 feet high; common in woods and rocky places.
Grossularia missouriensis (Nutt.) Cov. and Britton. — Native from Tennessee
to Kansas, north to Minnesota and South Dakota. Berry not prickly, purplish.
Bush to 6 feet high. The Glcnridale, derived from this crossed with European
varieties, is very vigorous and. productive and stands the hot summers better
than other gooseberries.
Orossularia divaricata (Dougl.) Spach, the coast gooseberry. — Native from cen-
tral California to British Columbia. Berry small, dark purple or black, not prickly.
Bush 6 to 10 feet. Trebla, a variety propagated by A. F. Ettcr, is supposed to
have been derived from a cross of this species with cultivated varieties.
Orossularia hirtella (Michx.) Spach. — Native from West Virginia to South
Dakota and north to Newfoundland and Manitoba. Berry purple or black, not-
prickly. Bush to 3.5 feet. Houghton, Downing, Pearl, Carrie, Oregon, and other
varieties are considered to have been derived from crosses of this species with the
European varieties. It has given mildew resistance to American varieties.
Orossularia oxycanlhoides (L.) Mill. — Native from Michigan to North Dakota,
north to Newfoundland and the Yukon. Berry smooth, purple, sweet, good;
bush low, spreading; branches bristly. A hardy, far-northern species.
Orossularia nivea (Lindl.) Spach, the Snake River gooseberry. — Native to
northern Nevada, Idaho, eastern Washington, and Oregon. Berries smooth,
bluish black, very good; bush 5 to 10 feet high; somewhat similar to O. miseour-
Grossularia curvata (Small) Cov. and Britton. — Native from Georgia to Texas.
Berry green to purplish, smooth; bush low, spreading; branches arching. Promis-
ing for breeding, because native to the South.
Grossvlaria echinella Cov. — Native to northern Florida. Berry very prickly,
large, green, bush spreading. Promising for breeding because native to the South
and because of its large fruits.
Orossularia roiundifolia (Michx.) Cov. and Britton. — Native from North Caro-
lina to Massachusetts in rocky places in woods. Berries smooth, purplish; bush
with slender arching branches.
Grossularia irrigna (Dougl.) Cov. and Britton, the inland black gooseberry. —
Native to western Montana and eastern Oregon, north to British Columbia.
Berries smooth, purple or black; bush 3 to 10 feet high.'
Besides these species there are others in the western United States
that may be of value. Thus Grossularia lobbii (A. Gray) Cov. and
Britton, G. pinetorum (Greene) Cov. and Britton, G. sericea (East-
wood) Cov. and Britton, and G. marshallii (Greene) Cov. and Britton
have large fruits but with prickles or glandular bristles. Of the species
listed above, G. nivea is possibly one of the most promising for breeding.
SYSTEMATIC BREEDING WORK WITH CURRANTS
AND GOOSEBERRIES
Very little systematic breeding work has been done with currants
and gooseberries. The fact that nearly all the red currant varieties
grown in this country originated here indicates the possibilities for
CURRANTS AND GOOSEBERRIES 541
improvement of this fruit, particularly in breeding for resistance to
leaf diseases; and this is borne out by the more recent red currant work
at the Minnesota Agricultural Experiment Station. Varieties of red
currants resistant to cane blight (Botryosj>haeria ribis Gross, and Dug.)
and with foliage resistant to leaf spot (Septoria ribis Desm.) are needed
to make the currant a useful garden and commercial fruit in many
sections where it is now difficult to grow. The hardiness, drought
resistance, and great vigor of the American black currants (golden
currants) make this group also promising. Selections of these currants
are needed that mature many or all berries on a cluster, so as to reduce
the cost of harvesting.
Probably the greatest opportunity, however, is in gooseberry breed-
ing. The chief need is for fine-flavored, attractive-fruited varieties
that are resistant to leaf spot, to high summer temperatures, and to
mildew (Sphaerotheca mors-wvae (Schw.) Berk, and Curt.). Such
southern native species as Grossularia echinella and 6. eurvata endure
high summer temperatures and are resistant to mildew. Some resist-
ance to leaf spot seems to be shown by G. missouriensis and probably
certain other native species. European gooseberries cross readily
with Ameiican species, and the productiveness and vigor of the
hybrids have indicated how promising this line of work might be.
Poorman, though not so large as many of the European gooseberries,
is larger than the other hybrids and has greater beauty and better
flavor when ripe than European varieties now grown in this country.
The Glenndale has greater vigor than most other hybrids and far
greater vigor than the European sorts. American native species
range from Florida far north into Canada; and varieties with the size
of the European, the quality and beauty of Poorman, the vigor of
Glenndale, and the range of American species would bo welcome
additions to our garden fruits.
Work of Experiment Stations With Currants
and Gooseberries8
In South Dakota, crosses were made between the native wild goose-
berry of South Dakota (Grossularia missouriensis (Nutt.) Cov. and
Britton) and the large-fruited European varieties. The first hybrid
variety to be introduced was Sunset in 1924, followed in 1925 by Kabu,
Kaduza, Kami, Kanga, Kapoza, Kataga, Kawauka, Kazouta, Kaza, and
Kopa. In addition, the station has grown many thousands of seedlings
of the native gooseberry, selecting the best for a new generation.
Seedlings of the native wild gooseberry were first introduced in 1921,
and up to 1927 eight generations of seedlings had been raised.
Similar work in growing thousands of seedlings of the wild black
currant resulted in the selection in 1923 of large-fruited seedlings. Four
wore named and introduced in 1925 — Tonah, Atta, Mato, and Wanka.
In addition the Siberian black currant, collected by Hansen in 1897
in Siberia, was introduced in 1910.
In North Dakota, breeding with the gooseberry was begun in 1920,
the native wild gooseberry (Grossularia missouriensis) being crossed
e A. S. Colby (Illinois), O. L. Slate (New York), A. N. Wilcox (Minnesota), and A. F. Yeagcr (South
Dakota) kindly furnished dotails of the breeding work with currants and gooseberries at their experiment
stations.
542
YEARBOOK, 1937
with Oregon Champion, Transparent, Houghton, Downing, Copland,
Josselyn, and Carrie. The best combination was with the Oregon
Champion. In 1932 three of the seedlings were named and intro-
duced— the Pixwell, Abundance, and Perry. Pixwell is considered
especially good for jelly, preserves, and sauce. 0. setosa Lindl.,
another wild gooseberry from North Dakota, was also crossed with
Oregon Champion, and though the first hybrid generation was not
particularly promising, the second showed better seedlings. A. F.
Yeager, in charge, noted that red color of fruit was dominant over
green, smooth fruit over downy, and long pedicel and peduncle over
short. He also found a dwarf plant type in Oregon Champion crosses
and observed that a light-green color of unripe fruit was apparently,
dominant over dark-green color. He is studying inheritance of thorns,
winter hardiness, and drought and heat resistance.
In New York gooseberry breeding was begun at the New York
(State) Agricultural Experiment Station at Geneva in 1892 and has
been continued at intervals since. The Fredonia, introduced in
1926, is the only variety resulting from the work. It is a seedling of
Crown Bob and is large, late, and productive for an English type.
Among the varieties crossed are America, Boskoop, Black Champion,
Chautauqua, Crandall, Downing, Honing Fruheste, High Sheriff,
Hough ton,. May Duke, Lancashire Lad, Pale Red, Wellington Glory,
Whitesmith, and Victoria. This station maintains a very large col-
lection of species and varieties.
A small number of currant crosses have been made, but no varieties
have been introduced. A large collection of currant varieties and
species is also maintained. George L. Slate reported that crosses
have been made as follows:
Fay X Missouri Sweet Fruited.
Fay X Crandall.
White Transparent X Crandall.
Cherry X Crandall.
Black Naples X White Transparent.
White Transparent X Black Naples.
Diploma X Black Naples.
Lee (black) X Mountain (gooseberry).
Black Naples X Downing.
Boskoop (black) X Poorman.
Lee X Poorman.
Boskoop X Ribes sanguineum.
Chautauqua X Grossularia echinella.
R. nigrum L. X Ozonne.
Honing Fruheste X R. pinetorum.
Honing Fruheste X R. lacustre. (?)
May Duke X R. pinetorum.
May Duke X R. lacustre.
R. pinetorum X R. lacustre.
R. pinetorum X R. odoratum.
R. pinetorum X R. innominatum.
R. lacustre (?) X R. pineimum.
In Minnesota the breeding of gooseberries was begun in 1909 and
has been continued since. Carrie, Chautauqua, Columbus (fig. 2, A),
Houghton, Josselyn, and Pearl have been intercrossed and crossed
with selections of wild species. Ribes hirtella Spach has been used to
obtain thornlessness. Como, a cross of Pearl X Columbus, was intro-
duced in 1922. It has resistance to sun scald and to disease and is
productive. It is especially good in cooking qualities.
The raising of seedling currants was begun in 1912 and has been
continued to the present. No crossing has been done. The Red
Lake-variety was introduced in 1933, being selected for the large size
of the berry and of the cluster and for its productiveness. It is
succeeding well in New Jersey and in other Eastern States.
In Illinois the work with gooseberries was begun in 1924 with the
objective of obtaining greater production, larger size, higher flavor,
CURRANTS AND GOOSEBERRIES 543
lower thorns, and disease-resistant foliage. Poorman, Spinefree,
Chautauqua, Carrie, Glemidale, and Transparent have been inter-
crossed, and over 2,000 seedlings are under test. Papers by Colby,7
in charge, indicate the accomplishments.
Work ov the United States Department of Agriculture
with Currants and Gooseberries
The work at the United States Northern Great Plains Field Station
at Mandan, N. Dak., under W. P. Baird, has consisted largely in
raising seedlings and making selections of the native hardy, drought-
resistant, productive- wild black currant Ribes odoratum. In 1924,
selections of this currant were crossed, and about 50 selections have
been made. Baird has noted that black fruit is dominant over yellow
and red and that a round shape is dominant over oblong. Some
gooseberry and red currant breeding has been done. The drought
of 1930 killed most of the gooseberry and red currant selections, but
the blade currants withstood it.
At Corvallis, Oreg., a collection of the best-i'ruited forms of the
native species of currants and gooseberries was made by L. N. Good-
ding, and hybridizing was begun by George F. Waldo.
At Washington, D. G, crosses have been made in recent years by
F. V. Coville and O. M. Freeman between Grossularia echinella, a
gooseberry species' native to Florida, and cultivated varieties.^ Several
selections were made, and the second hybrid generation is being raised
at Beltsville, Md.
In 1932 the Glenndalc gooseberry was introduced. This originated
as a seedling raised by the late W. Van Fleet probably about 1905,
before he joined the Department of Agriculture, from a cross of
( (G. missou'riensis X Red Warrington) X Triumph) X Keepsake. It is
a. very rank-growing variety, which succeeds from Maryland and Vir-
ginia to Kansas, at the southern limit of gooseberry growing.
CumiANT and Gooseberry Breeding in Foreign Countries
The Dominion station at Ottawa, Canada, has introduced at least
four varieties of gooseberries — Charles, Silvia, Mabel, and Spinefree,
the last-named being a cross of a second-generation thornless wild
with Mabel. It is described as of good flavor, thick-skinned, bright
ra\, free of spines, upright, vigorous, free of mildew, and resistant to
leaf spot.
This station also introduced the following 12 black currants origi-
nated by William Saunders before he became director in 1887: Climax,
Clipper, Eclipse, Ethel, Kerry, Magnus, Ogdcn, Ontario, Saunders,
Success, Topsy, and Winona. Of these, Kerry, Clipper, Eclipse,
and Climax arc recommended varieties in Canada.
At the East Mailing Horticultural Research Station in England,
the production of improved varieties of red and black currants is a
breeding project. The use of X-rays to induce mutations, and a
study of inheritance in black currants, are two lines of research now
under way.
"Coi.hy, A. S. size imhehitance ik uoo.sEHEKiiv ffcits. Amor. fioc;. )Jort. Sei. Proo. (1933) 30: 105-
107. .MM.
IXI1EIUTAXCE OF UOOSEBEHKY LEAF INFECTION. AlllOr. SoC. Ilort. Sei. Pl'OO. (1934) 32: 397-399.
1930.
544
YEARBOOK, 1937
At the University of Bristol production of heavy-cropping varieties
of black currants is one objective, and two varieties have been named
and introduced. At times some gooseberry breeding for mildew
resistance has been carried on at this station.
Laxton Bros., of Bedford, England, have done much breeding work
with black currants and gooseberries, and some with red currants.
They have introduced the following red currants and gooseberries:
Table ]. — Currants and gooseberries introduced l>y Laxton Bros., of England
Variety
Bed currants:
Perfection
Laxton's No. 1..
Gooseberries:
Bedford Yellow.
Amber
Bedford Eed-...
Green Gem
Emerald
Oolden Bali.
Year
intro-
duced
19011
l'J2.i
1915
v.m
1922
1922
1925
1928
Kearguard . 1928
Superior qualities
Gold Drop X Drill.
AVonderful X Lancaster Lad .
Crown Bob X Langley Green .
Drill X Whitesmith
Drill X Crown Bob
Drill X Whitesmith.
Wonderful X Lancaster Lad .
Long clusters, sweet, large.
Vigorous, productive.
Golden yellow, high flavor, large.
Amber color, high flavor,
lied, productive.
Yellowish green, high flavor.
Early, green, productive.
Yellow, high flavor.
. j Very late, firm.
In Sweden, C. G. Dahl, in charge of the gooseberry breeding at
Alnarp, reported that breeding was begun in 1911 to obtain mildew-
free varieties. Orossularia divaricata (Dougl.) Cov. and Britton and
6. nivea (Lindl.) Spach were crossed with European varieties. Some
1,000 plants were raised, and one variety, Scania, has been introduced.
It is free from mildew and produces a strong plant and large fruit.
A second variety, a second-generation hybrid from S. nivea X a
European variety, is being distributed under the name Centum. It
is also free from mildew, with fruit like Downing, of fine flavor.
In the Union of Soviet Socialist Kepublics, I. V. Michurin originated
one gooseberry variety, Shtambooii, which was reported to be resistant
to mildew.
SOME UNUSUAL OPPORTUNITIES
IN PLANT BREEDING
GEORGE M. DARROW, Senior Pomologist,
GUY E. YERKES, Horticulturist, Division
of Fruit and Vegetable Crops and Diseases,
Bureau of Plant Industry
0,
'PPORTUNITIES for the development of new and improved
plants by breeding are by no means limited to those now grown in
home or commercial gardens. All our present cultivated plants, it
must be remembered, have been derived from wild plants. Those
that were most outstandingly useful or most readily adaptable to
cultivation, man took from forest and field and grew in his own door-
yard. Others he left in their wild state, for one reason or another,
though he continued to use their products. One of the plants left
wild until very recently was the blueberry. The work of the late
Frederick V. Coville, described elsewhere in this Yearbook, shows
how modern knowledge and modern technique, applied to suitable
wild material, can change and improve it enormously for human
uses. Not all neglected wild plants, undoubtedly, would produce
such splendid results as the blueberry under Coville's handling,
but the achievement suggests that there is .a wealth of material
not yet touched, awaiting merely the right imagination and the
right opportunity for the breeder to transform it in. greater or less
degree.
Some of the native wild plants and introductions from foreign
countries need only careful selection of superior strains to increase
their usefulness. In other cases a planned program of breeding is
necessary, including crosses with types already in cultivation. It
must be recognized that hybrids between distinct species are made
with considerable difficulty in most cases, and only rarely are they
directly valuable in a horticultural way. However, occasionally
valuable things do come from such distant crosses, and the only way
to find them is to make the attempt.
PLANTS THAT AWAIT THE BREEDER'S ATTENTION
Some of this material may be mentioned at random here. In the
Northeastern States some people use milkweed like asparagus and
also make soup of it. If varieties with many short intcrnodes on their
underground stems could be located and improved by breeding,
they might be a welcome addition to the perennial vegetable garden.
Different colored varieties of the butterfly milkweed might be selected
and bred as ornamentals. Strains of the hard or sugar maple that
came true to various autumn leaf colors would be desirable additions
to our list of shade trees, and others might be found with unusually
high sugar content in the sap, to be used in the sugar bush. Search
545
546 YEARBOOK, 1937
might reveal strains of longleaf pine trees having high turpentine
yield. Trees of upright narrow form have special value in landscape
use, especially for screens, high hedges, and narrow streets. Lom-
bardy poplar, quite widely used for this purpose, usually proves
short-lived. If more varieties of long-lived trees of this form could
be developed, they would be valuable additions to our nursery
products. Such forms have been propagated from American elm,
several species of maple, English oak, oriental cherry, and others,
but they have never been as extensively planted as this form warrants.
Chinese elm apparently has received little attention from the stand-
point of developing varieties of columnar or pyramidal or low-growing
dense form, though such varieties would be useful, especially in sec-
tions subject to drought and other conditions adverse to some of the
other trees.
Native hardy rhododendrons and azaleas are a fascinating group
for breeding, with the object of developing varieties that would
endure the summer heat encountered from Philadelphia southward
better than present varieties, and also of increasing the winter-hardi-
ness of some Asiatic forms, especially Rhododendron obtusum Planch,
and allied species. Although this group of plants is rather limited
in its adaptability because of soil and climatic requirements, its use
is increasing very rapidly wherever any of its diverse forms can be
grown well. R. calendulaceum Torr., the flame azalea of the southern
Appalachians, owing to its hardiness and splendid range of colors,
offers a good subject not only for crossing with other species but also
for selecting the best specimens in the wild and propagating them
as varieties.
There are many unusual or unimproved native and introduced
fruits awaiting the attention of the breeder. Some of these have
been studied more or less casually, but many are worthy of systematic
continued study. For the Northern States there are the barberries
(Berberis spp.); buffaloberries (Shepherdia spp.); cornelian-cherry
(Cornus mas L.); elderberries (Sambucus spp.); hawthorns (Crataegus
spp.); honeysuckles (Lonicera spp.); juneberries, known also as shad-
berries, shadblow, or sarvisberries (Amelanchisr spp.); mulberries
[Mortis spp.); mountain ash (Sorbus spp.); wintergreen and salal-
berries (Qaultheria spp.); and for the more southern States, elder-
berries, juneberries, the mayhaw (Oraetaegus aestivalis Torr. and
Gray), the species of Eugenia, feijoa (Feijoa settowiana Berg.), the
pawpaw (Asimina triloba L.), and the persimmon (Diospyros virginiana
L.). The writers have been especially interested in the actinidias,
the American cranberrybush, several species of Elaeagnus, the oriental
quinces, and the Chinese bush cherries. Brief discussions of these as
material for the plant breeder are given in the following pages. Some
of the other fruits previously listed are just as promising, but they
have not been so readily available to the writers.
ACTINIDIA
The actinidias (known also as Chinese or Japanese gooseberries and
sheep peaches) are climbing shrubs, chiefly of eastern Asia, ranging
from the northern part of Japan south to the tropical islands.
UNUSUAL BUSH FRUITS
547
Some seven species are in cultivation chiefly as ornamentals, for their
beautiful foliage is remarkably free from insects and fungi. Two species,
at least, are worth cultivating for their fruit, Actinidia arguta Miq.,
which is hardy in New England (fig. 1), and A. chinensis Planch.,
which is hardy north to Washington, D. C, though the growing
season does not seem to be long enough at Washington to mature the
fruit. In southern California very fine crops of A. chinensis are some-
times produced. The fruit of A. arguta is about an inch long, that of
A. chinensis up to 2 inches, or about the size and shape of a medium
to small hen's egg. The fruit is tart until fully ripe, when it is sweet,
with a texture somewhat like that of a fresh ripe fig. It is used fresh,
for jelly, and for sauce. The leaves of A. chinensis are relished by
cats, like catnip. Michurin, the Russian plant breeder, has intro-
Figure 1. — One of the actinidjag (Actinidia arguta) on a trellis at the Arnold Arhoreliim,
Boston, Mass. The actinidias are potentially important food plants of the United
States, just awaiting the study of a plant breeder. This species bears fruit about
an inch long; but another kind, .-/. chinensis, bears fruit up to 2 inches long.
duced five varieties, Ananasia Michurin, Clara Zetkin, Pozdniaia
(late), Raniaia (early), and Urezhainaia (high-yielding). The beauty
of the vines, then wide climatic adaptation, their vigor, and the pleas-
ing flavor of the fruit make them promising for the United States.
They are readily propagated by softwood and hardwood cuttings
and by layering. The one need is the origination of varieties regularly
productive, for the seedlings now grown only rarely produce heavy
crops. A single vine may produce several bushels of fruit one year
and only a few fruits most years. Hybrids between A. arguta and
A. chinensis were raised by David Fairchild, but the hybrids never
fruited.
548
YEARBOOK, 1937
Figure 2. — The American cranberrybush in flower. The large white marginal flowers
around each cluster are sterile. Only the small inner flowers set fruit.
AMERICAN CRANBERRYBUSH
The fruit of the native American cranberrybush, highbush cranberry, or
pembina {Viburnum trilobum Marsh.),1 is used for jelly making in sec-
tions of the northern United States and Canada.2 From the fruit is
produced a jelly rich in color and in pectin but of relatively strong flavor
and odor. The fruit resembles that of the cranberry in color and suze, but
1 Formerly known as Viburnum amerkanum Mill.
'Dabrow, O. M. viburnum americanum as a garden fruit. Amer. Soc. Hort. Sei. Proc. (1923),
20:44-54. [1924.]
the American cranberrybush. . . . Jour. Heredity 15: 243-253, illus. 1924.
UNUSUAL BUSH FRUITS
549
the plants are not related.
The fruit of the American
cranberrybush is borne on
a high bush in clusters,
like the elderberry, while
the cranberry is borne on
a low vine. The American
cranberrybush is a close
relative of the elderberry
and grows to about the
same height and in sim-
ilar clumps with similar
flowers (fig. 2 ) . It is suffi-
ciently hardy to grow in
the colder parts of the
United States. It is often
confused with the Euro-
pean Viburnum opulus L.,
which is widely used in the
United States as an orna-
mental, but is readily dis-
tinguished from the latter
by its clear, acid fruit.
The fruit of V. opulus is
so intensely bitter as to
be inedible.
In the spring of 1921
the Bureau of Plant In-
dustry took over for 10
years a plantation of the
American cranberrybush
established by A. E. Mor-
gan, formerly president of
A.ntiochCollege,now chair-
man of the Tennessee
Valley Authority, at East
Lee, Mass. The plants
were the best obtainable
selections following a per-
sonal survey by Morgan of
this frui t in the wild in New
Figure 3. — Three varieties of
the American cranberry l>u>li in-
troduced by the United States
Department of Agriculture
through cooperating nurseries:
A, Wentworth; fl, Hahs; C,
Andrews. The fruit is used for
making jelly, which is as rich,
red, and firm as that made from
the currant and the cranberry.
At
«£*
M
fife
r ■■*■ J
* • r
rs&
+y
i *T *
. i
J* *
1 -'•
j ^'V
■//I
j_
-4
•
» * ■
" ■ 9
*
m
550
YEARBOOK, 193 7
York and New England and even in Manitoba and Saskatchewan. Fruit
was obtained through correspondence from Alaska to Newfoundland.
After a study of the selections at East Lee, and of plants in the
wild in various regions, three were named, propagated, and intro-
duced— Wentworth, JIahs, and
Andrews (fig. 3). Analyses for
acid and pectin and jelly tests by
('. A. Magoon, of the Bureau of
Plant Industry, indicated that
these three were superior to the
other selections. They also cov-
ered a long season, Wentworth
being early, Ilahs midseason, and
Andrews latest. Through coop-
erating nurseries these three va-
rieties arc now available in the
trade. They are propagated by
softwood and hardwood cuttings
and by layering (fig. 4).
Many northern State experi-
ment stations have cooperated
with Morgan and the United
States Depart meat of Agriculture
in testing this fruit, and several
are continuing their interest in it.
These stations include those in
Maine, New Hampshire, Massa-
chusetts, New York, Wisconsin,
Minnesota, North Dakota, Mon-
tana, and Idaho.
Besides being of value for its
fruit, the American cranberrybush
is a widely used ornamental, beau-
tiful in flower and fruit, with a rich
green summer foliage which be-
comes highly colored in fall (fig. 5).
Rchder states that there are in
all about 120 species of Viburnum,
nearly all natives of the cooler
sections of the Northern Hemis-
phere. Many are bitter-fruited,
many others are sweet-fruited,
and some bear clear, acid fruit.
It would seem that the viburnums have great promise for the breeder
because of their value as ornamentals as well as for fruit production.
Species such as V. carlesii Hcmsl. and V.jragrans Bungc are delight-
fully fragrant, while sterile forms of V. opulus L. and V. tomentosum
Thunb. are the snowballs of commerce. Valuable hybrids would prob-
ably result from crossing the Andrews, Hahs, and Wentworth with V.
carlesii, V.jragrans, the evergreen V. rhytidoj)hyllum Hemsl., selections
of V. lantana L. and related sweet-fruited species, the clear acid-fruited
V. wrightii Miq., and V. dilatatum Thunb.
Figure 4. — Propagation of the American
cranberrybush by hardwood endings. In
this case some roots were produced along
the cutting, but the largest number came
from the base of the new growth («).
UNUSUAL BUSH FRUITS
GOUMI OR ELAEAGNUS
551
Goumi is the name applied in Japan to several species of Elaeagnus
grown chiefly for their ornamental value. One species, the cherry
elaeagnus (Elaeagnus multiflora Thunb., fig. 6, C), is also of value for
^2 *iJ3* «£
1
?5 ^1
W^^~- "^H
Pjtf^fi
Ik.
3*--
*■ -:
Figure 5. — The American cranberry bush is ornamental in flower (A) as well as in
fruit (B). Both the white flowers and the brilliant red fruit contrast well with the
foliage. It is one of the highly prized and widely used ornamentals of the northern
part of the United States.
its tart fruit. Another subtropical species, E. philipgensis Perr.,
called the lingaro, has produced well in southern Florida. It has
edible fruit prized for use in sherbet. Still other species, such as E.
ovata Serv. (fig. 6, A) and E. umbellata Thunb. (fig. 6, B), bear im-
mense quantities of small fruit.
552
YEAR HOOK. 1937
Figure 6.— Elaeagnus or goumi: A, Flowers of Elacugnus ovate; B, fruil of E. umbellata;
C, fruit of E. mullifloru, the largest-fruited one. These hardy, drought-resistant.
fruiting shrubs are valuable as ornamentals and as food for wildlife. E. muitiflora
is a valuable food plant of parts of Asia.
UNUSUAL BUSH FRUITS 553
Though the cherry elaeagnus was introduced into this country
many years ago, it has not become an important fruit even in the
garden. The explanation seems to be that it has been almost entirely
grown from seed. The seedlings are extremely variable, some pro-
ducing very little fruit and that small and astringent, others pro-
ducing abundant fruit as large as cherries and having a pleasant flavor.
Elaeagnus seems worth the attention of the breeder because the
fruit is of considerable importance in parts of central Asia, the plants
are very hardy and drought-resistant, the seedlings are quite variable,
and there are a great many species. A breeding program might
include selections of the best fruiting forms from large numbers of
seedlings, and hybridizing between species such as Elaeagnus multi-
flora, E. ovata, E. umbellata, and E. pungens Thunb. In the South-
ern States the fragrant October-flowering species E. pungens may be
of some value for its fruit and for hybridizing.
ORIENTAL QUINCES
The oriental or flowering quinces include three species and many
varieties, as well as certain hybrids. The best-known species, Chaeno-
meles lagenaria Koidz. (Cydonia japonica Pers.), is the so-called
Japanese quince, which, however, is a native of central China. It is a
spreading shrub with thorny interlacing branches, from 4 to 8 feet
high. The dwarf Japanese quince, Chaenomeles japonica L., is a
sprawling shrub with spiny branches and orange-scarlet blossoms.
One hybrid between these two species, named Chaenomeles superba
Rehcl., has blood-red flowers. The flowers of these two species and
their hybrids resemble apple blossoms and range from white to salmon
and scarlet and even darker. One of the scarlet-flowered varieties
most commonly propagated is so covered with flowers in early spring
that it is sometimes called "fire bush."
Though ordinarily cultivated for the ornamental value of the bush
in flower, the fruit (fig. 7, A) is of value for its acidity and pectin
content. It has little flavor, but when used in making jelly and
preserves with apples, cherries, plums, prunes, and the other cultivated
quinces it helps to achieve the balance in the ratio between sugar and
acid that is necessary for highest flavor. Tests have been made, in
cooperation with the National Preservers Association, to select varie-
ties for this purpose. The variety grandiflora, of Chaenomeles lage-
naria, with fruit 3 to 4 inches in leugth and weighing one-fourth to
one-third of a pound, was the largest and most productive at Glendale,
Mel., and contained the most malic acid, 5.75 percent.3 It has apple-
pink to rose-pink flowers (fig. 7, B).
Because the flowering quinces are largely self-sterile, most people,
having only a single bush or only one variety, have never seen the
fruit. The varieties C. lagenaria var. baltzii (cerise-pink flowers),
C. lagenaria var. versicolor (pink flowers), C. superba var. atrosanguinea
(fiery scarlet flowers), C. japonica var. candidissima, and C. japonica
var. nivalis (white flowers) all bear heavily, and though no tests have
been made, some of them may bo expected to pollinate the variety
grandiflora of C. lagenaria. Colby,4 of Illinois, found that C. lagenaria
> Latiikop, C. P., and W ai.de, W. L. the Japanese quince. Fruit Prod. Jonr. 7 (4): 14-18, illus.
4 Colby, A. S. some notes on the Javanese quince. 111. State Acad. Sci. Trans. (1928) 21: 176-185,
illus. 1920.
138904°— 37 ;i6
554
YEARBOOK, 1937
Figure 7. — The flowering quince (Chacnomeles tagcnaria), a beautiful ornamental but
also useful for its fruit (A), which is high in malic acid and pectin. B, Variety
grandiflora, propagated originally for its apple-pink flowers but bearing very large
fruit of very high acid and pectin content.
UNUSUAL HUSH FRUITS 555
var. grandiflora was at least partly self -fertile, but no other variety
that he tested was at all self-fertile. He has found the fruit of C.
lagenaria var. versicolor fully as large as that of the variety grandiflora
under his conditions.
The fruits of several varieties arc fragrant and are used to perfume
rooms. Colby lists the varieties baltzii and atrosanguinea as having
much perfume. The Chinese cover the fruits with a coat of thin oil
and keep them in the houses a long time.
Another species from China, Chaenomeles sinensis Koehne, is a
small tree bearing its flowers singly and having fruit of enormous size,
Tip to 6 inches or more in length. Though its fruit may also be used
as a source of acid, it is coarser and has less acid and pectin than the
other species. It has a strong flavor, and a small proportion will
impart a pleasing suggestion of quince to jelly and preserves made
from milder flavored fruits. It is very fragrant and is also used to
perfume rooms. The foliage turns a brilliant scarlet in the fall, making
it desirable for tall hedges and for ornamental plantings.
The two flowering species, Chaenomeles lagenaria and C. japonica,
are hardy as far north as Massachusetts, New York, and Illinois, and
may be raised southward to northern Georgia, or as far south as
there is sufficient winter cold to break their rest period. The other
species, O. sinensis, is hardy north to Philadelphia and may be raised
in the South nearly to the Gulf of Mexico.
So far, improvement in the fruit characters of this group has been
largely accidental. The high acidity and pectin content of the fruit
of some varieties suggests that attempts to obtain still larger amounts
would be desirable. Improvement might be made by developing
larger sized and more handsomely colored fruit in varieties adapted
to different regions, by securing more open growth so that the fruit
can be picked more easily, by eliminating thorns on the bushes, and
by developing self-fertile varieties. So far no hybrids with the Euro-
pean cultivated quince are known, but attempts should be made to
produce them.
The possible importance of this fruit in the preserving industry is
indicated by the following quotation from Lathrop and Walde:5
Were a preserver to name the properties most needed in a new fruit by the
preserving industry today, he would unwittingly be describing the Japanese
quince ***.*** j^g bid for recognition and economic importance is
not based upon its becoming a new, distinctive-flavored product. It serves a
very different purpose: — to supply a non-flavored fruit, or fruit juice, very high in
1-malic acid and pectin to those popular flavored fruits as the apple, cherry,
European quince, and plum or prune when requiring additional 1-malic acid.
* * * These familiar flavors of jellies and preserves when they reach the con-
sumer in many instances do not show off to their best advantage. * * * the
marked effect and advantage of making small, definite additions of fruit acid in
jellies and preserves was described in the case of some fruits to bring out more of
the total fruit flavor actually present.
CHINES]*: AND OTHER BUSH CHERRIES
The Chinese bush, Manchu, or Nanking cherry, Prunus tomentosa
Thunb. (called by the Chinese the mountain cherry),6 has been grown
in the United States some 50 years as an ornamental shrub but now
' Lathkoi>, C. P., and Walde, W. L. See p. 14 of reference cited in footnote 3.
6 Dakkow, O. M. the cuinese bush (.'uekky . . . Jour. Heredity 15: loa-176, illus. 1924.
556
YEARBOOK, 193 7
is attracting attention for its fruit. It is one of the earliest of all
shrubs to flower in the spring, its white to pink blossoms (fig. 8)
opening just as the leaves start to unfold ana its brilliant red fruit
Figure 8. — Flowers of llie Chinese bush cherry. It flowers on the previous
season's growth.
(fig. 9) ripening with the last of the strawberries. The fruit has a
range in flavor and texture from the sweet to the sour cherry with a
peculiarly attractive tang. It is as large as the wild cherries of
UNUSUAL BUSH FRUITS
557
Europe, from which the cultivated sweet and sour cherries have
originated. The foliage is resistant to the common cherry leaf
troubles. The tree is cultivated to some extent in China, and the
fruit is also gathered in the wild and sold in the markets. The range
of the Nanking cherry in Asia is from southern Manchuria to the
Kashmir region of northern India, a region for the most part semiarid
and in latitude and climate comparable to the territory from eastern
New Mexico northward to North Dakota.
Fifftra 9.— The Chinese bush cheery in fruil. Its brilliant red fruits range in flavor
from the sweel to the sour cherries. They are produced in great abundance pro-
vided they escape spring frosts and brown rot. Objectives in breeding tliis fruit
should include late-flowering, brown rot-resistant seedlings.
When they escape spring frosts and severe attacks of brown rot,
the bushes are loaded with fruit of the size of small sour cherries.
The most needed improvements are the introduction or discovery of
late-flowering and brown-rot-resistant seedlings (fig. 10). The brown
rot fungus often kills back twigs and branches in humid sections.
Harlow Rockhill, strawberry breeder at Conrad, Iowa, has crossed
the Nanking cherry with the western sand cherry, Prunus besseyi
Bailey, and has grown several generations of hybrid seedlings. He
feels that some are very promising for Iowa conditions, as they flower
later and are less often injured by cold than the Nanking cherry.
Importations are needed from different regions to make selections
adapted for the coldest to the warmest, and the driest to the most
humid regions of this country. Rockhill has crossed the Nanking
cherry with the Napoleon (Royal Anne), Montmorency, and Zumbra
cherries, and there is the possibility of obtaining hybrids with many
other cherries. The Arnold Arboretum reported having a natural
hvbrid between P. tomentosa and P. triloba Lindl. in their plantings.
558
YEARBOOK, 193 7
Slate,7 of the New York (State) Agricultural Experiment Station, has
selected fine fruiting seedlings at Geneva and has started propagating
them. By and large, it is a promising fruit for the plant breeder, and
it may have commercial possibilities.
Figure 10. — Seedling plants of the Chinese hush cherry; in the middle an early flower-
ing, at the right a later flowering, and at the left a much later flowering sort. These
seedlings illustrate the possibility of obtaining much later flowering selections that
may escape unseasonable frosts.
Prunus glandulosa Thunb. and P. japonica Thunb. are very hardy
dwarf shrubs that are ornamental and have deep red to purple-black
fruits useful for pies, jellies, and sauce. There are also many other
species of bush cherries in Asia that may be worth using in breeding.
Besides the bush cherries, P. triloba, classed as a flowering almond, is
possibly a still more beautiful hardy flowering and fruiting shrub with
flowers of pure pink.
'Slate, G. L.
2S-31. 1930.
THE improvement of IKLNUS tomentosa. Amer. Soc. Hort. Sci. Proc. (1929) 2fS
IMPROVING THE
WILD BLUEBERRY
FREDERICK V. COVILLE, Principal
Botanist, Division of Plant Exploration and
Introduction, Bureau of Plant Industry
I
N 1906 the writer began a series of experiments to learn the fundamen-
tal facts in the life history of the blueberry, which might serve as a basis
for the possible cultivation of this delicious wild fruit. It took 2 years to
find that the blueberry plant requires an acid soil. These experiments
showed also thattrailing-arbutus, rhododendrons, azaleas, mountain-
laurel, pink ladyslipper, and many
other plants require acid soils.
Although every gardener to-
day knows that blueberries, as
well as hundreds of other kinds of
plants associated with blueberri es
in their wild habitats, thrive only
in acid soil, that fact apparently
was not known to American hor-
ticulturists prior to these experi-
ments with blueberries. The
Cyclopedia of American Horti-
culture,published in four volumes
in 1900, and prepared with the
collaboration of more than 200
horticulturists and botanists of
the United States, contains no
mention that an acid soil is re-
quired for the successful cultiva-
tion of any one of these plants.
BEST WILD BLUEBERRIES
CHOSEN FOR BREEDING
PURPOSES
figure 1. — Frederick V. Coville, assistant
botanist and principal botanist, United
States Department of Agriculture, 1888-
1937; first breeder of blueberries and founder
of the industry of blueberry culture.
After the soil-acidity require-
ment of blueberries had been de-
termined, 2 years more were de-
voted to further studies of the life
lustory of the blueberry, and by the end of 1910, when the first bulletin
was published,1 the blueberry had been grown successfully from seed to
fruit ; selected plants had been propagated by grafting, budding, di-
vision, layering, twig cuttings, and root cuttings ; methods of pollination
had been devised and applied ; and wild plants with superior fruit had
been chosen as the basis for breeding experiments.
'Coville, F. V. experiments is blueberry culture.
193, 100 pp., illus. 1910.
U. S. Dept. Agr., Bur. Plant Indus. Bull.
559
560 YEARBOOK, 1937
DR. COVILLE died suddenly on January 9, 1937, only a few ivecks after
he had completed the article that appears herewith. It is fitting that his last
paper deals with the greatest of his achievements in agriculture. His work
in domesticating and improving the blueberry was based upon years of taxo-
nomic, physiological, and genetic investigation of the wild blueberries of the
eastern United States, and the flourishing industry fathered by his efforts
rests upon a sure foundation of scientific knowledge.
Yet the bluebeiry achievement is but one of many in his chosen science,
botany. In 1888, the year after his graduation from Cornell University, he
entered the Department of Agriculture, and in 1891 he accompanied the
famous Death Valley expedition in the capacity of botanist. As a result
there was published in 1893 Botany of the Death Valley Expedition, one of
the classics of the study of desert vegetation. Soon Coville was back again
in the far West, investigating the useful plants of the American Indians and
carrying on, in collaboration with the foresters of the Department, funda-
mental studies of the grazing and browse plants of the national forests. The
present gr a zing-management policies of the Forest Service are the outcome,
in large measure, of these investigations.
No one who had the privilege of being in the field with Dr. Coville could
fail to be impressed by his keenness of observation and his constant appre-
ciation of the beauty and the human appeal as well as the scientific interest
of plants. The few examples of his work mentioned in the preceding para-
graphs give only a partial view of his wide-ranging interest. He published
no fewer than 158 scientific papers. Aside from his own special investiga-
tions, he played a leading part in such enterprises as organizing the research
work of the National Geographic Society, establishing the Desert Botanical
Laboratory of the Carnegie Institution of Washington, and founding the
National Arboretum. With F. L. Olmsted and H. P. Kelsey, he edited
that indispensable aid of the horticulturist, Standardized Plant Names.
The writer tvell remembers Coville's delight, while the book was in prepara-
tion, when he or one of his colleagues would hit upon an apt and attractive
English name for some plant hitherto known only in Latin or Greek.
Dr. Coville had a host of friends in all walks of life, to whom he was a
patient and kindly counselor. Because of his reputation for sturdy good
sense, people sought his advice, and he never begrudged for this purpose time
that he could ill spare from his many occupations. The deep sense of loss
his colleagues feel at his death is intensified by regret that he did not live to
make one more trip to Death Valley, the scene of his first important botanical
discoveries, as he had planned to do this spring. The popular flora of the
Death Valley region he was engaged in writing would have been a most
appropriate conclusion of a busy, useful, and happy life.
T. H. Kearney.
BLUEBERRIES 561
Brooks Blueberry
The first wild blueberry selected for breeding purposes was Brooks,
named after the owner of the pasture at Greenfield, N. H., in which
the plant was found. It was a highbush blueberry, Vaccinium
corymboswm L. The berry was discovered in July 1908, after three
summers of cursory observation in the mountains of southern New
Hampshire and 3 weeks of diligent search in the summer of 1908.
The bush grew at an elevation of 950 feet aboA-e the sea. It stood
with many other blueberry plants in an old, brushy, mountain pas-
ture, in acid and permanently moist but not swampy soil. It was
about 7 feet high, and the largest of the several stems was about 2
inches in diameter. The plant was old, and the tops on some of the
stems were partially dead. Other parts of the bush were in full vigor,
with robust twigs and foliage. It yielded 3 quarts of berries. The
berries were of large size, reaching a diameter of more than half an
inch. The flesh was firm and juicy. The color was an unusually light
blue, due to a dense bloom over the nearly black surface. In flavor
the berry was exceptionally good. It was sweet, but sufficiently acid
to be decidedly superior to the mild-flavored fruit of the lowbush blue-
berry, V. angustijolium Ait., yet not sour like the Canada blueberry, V.
canadense Kalm, and it possessed in a high degree the flavoring ester
that is the special characteristic of the best wild blueberries of New
England. The delicious flavor of this wild blueberry from New Hamp-
shire appears in all the cross-bred named varieties of blueberries
except Jersey and Wareham, and the flavor of those two varieties
would be more delicious if Brooks had been included in their ancestry.
This description of the Brooks blueberry has been given in detail
because I regard its selection as of fundamental importance to the
success of the Department's blueberry-breeding experiments. Every
breeder of race horses or of milk cows understands that the choosing
of the individuals to be interbred is of the highest importance. Plant
breeders usually select carefully the species they intend to interbreed,
but often make the mistake of paying too little attention to the choice
of superior individual plants within the species.
ATTEMPT TO IMPROVE THE BLUEBERRY THROUGH
SELF-POLLINATION A FAILURE
The first attempts to improve the blueberry by breeding were made in
1909 and 1910, when flowers on the original Brooks bush, and on
plants propagated from it by grafting, by budding, and by cuttings,
were pollinated by hand with Brooks pollen. These flowers did not
set fruit, or the fruit withered and dropped long before it was mature,
or if a few berries ripened they contained abnormally few seeds, most
of these lacking embryos. No plants resulted from the sowing of
these seeds. In later years self-pollination was tried repeatedly. In
some instances a few plants were obtained from the few seeds resulting
from such pollinations, but the plants were weak and they never pro-
duced fruit that was either desirable or abundant. This method of
breeding, therefore, so successful with com and with beans, was
finally abandoned as a means of improving the blueberry. Before
this subject is dismissed, however, it may be well to cite an experiment
562 YEARBOOK, 1937
in 1914 which shows how definite is the tendency to failure in self-
pollination as compared with cross-pollination in the blueberry. On
February 23 to 28 of that year 20 flowers on a hybrid blueberry plant
known as 393C were pollinated with pollen from another hybrid
blueberry, 394 Y. Nineteen of these twenty cross-pollinated flowers
set fruit and 19 berries ripened. On February 27 and 28, six
flowers on 393C were pollinated with the plant's own pollen. From
these six self-pollinated flowers no berries ripened. Five of the six
flowers set fruit at first, but these all shriveled and dropped while
they were still young and green. The failure of 3930 to produce
seeds when pollinated with, its own pollen was not due to sterility of
the pollen, for the pollen of this plant, when used in another experi-
ment, on 394Y, yielded an abundance of berries and seeds from which
many vigorous and productive plants were grown.
NUMBER OF CHROMOSOMES IMPORTANT
Another series of failures in the early blueberry pollinations was due
to a cause quite different from self-sterility. Certain species of blue-
berry usually yielded no fruit when cross-pollinated, among them
the lowbush blueberry and the Canada blueberry, species of similar
size and habit, which occur together in enormous areas on both sides
of the Canadian border; the highbush blueberry and the bigbush blue-
berry, Vaccinium atrococcum (A. Gray) Heller, which resemble each
other so closely that Asa Gray considered one a variety of the other;
and the highbush blueberry and the dryland blueberry, V. vacillans
Kami. When the two species of any of these pairs were cross-pollin-
ated they usually produced no fruit. If, however, any berries resulted
from the cross-pollinations, their few seeds produced weak and unpro-
ductive plants. In later years, cytological studies by Longley 2
showed that in each of these pairs the first-named species has 24
chromosomes; the other 12. The 12-chromosome species, it was found
later, cross freely with each other. They even cross with the deer-
berry, which belongs to a related genus, Polycodium, but which has 12
chromosomes.
Among the 24-chromosome species of blueberry, crosses could be
made easily, notwithstanding great differences in the physical appear-
ance of the two species that were crossed. Not only were the high-
bush and the lowbush blueberry hybridized by artificial pollination,
but natural hybrids between them are of frequent occurrence in New-
England pastures. The highbush blueberry grows to a height of 7
feet, with many stout stems in a single clump, and its leaves aro com-
monly 2 to 2% inches long by 1 to 1% inches wide, the margins usually
without teeth. The lowbush blueberry is 6 inches to a foot in height.
It spreads by slender rootstocks into broad patches, and its leaves are
small, narrow, and finely serrate. The highbush blueberry is easily
crossed also with the myrtle blueberry of Florida, Vaccinium myral-
nites Lam., a 2-foot species with evergreen, minutely-toothed leaves,
which are seldom more than three-fourths of an inch in length.
The highbush blueberry can be crossed easily also with the hairy
blueberry, V. hirsutum Buckl., a southern-Appalachian species 2 to
1 Covins, P. V. blueberry chromosomes. Science (n. s.) fit): o6.r>-5<)0. 1927.
Longley, A. E. chromosomes in vaccinium. Science (n. s.) 60: 566-oflS, illus. 1927.
BLUEBERRIES 563
3 foet high, with leaves densely pubescent on both surfaces, and with
hairy, black berries. In a word, ease of crossing, among blueberry
species of the eastern United States, is dependent on equality of
chromosome number. Blueberry species of the most diverse appear-
ance and characteristics, but with the same number of chromosomes,
hybridize readilv. n n
J " Russell Blueberry
The second wild blueberry selected for breeding purposes was
Russell. It was brought to my attention in 1909 by Frank Russell
as the best lowbush blueberry on his 600-acre mountain farm at
Greenfield, N. II. The original plant had become so shaded by the
low branches of a young oak tree that it no longer produced fruit, but
in the greenhouses at Washington its berries reached a diameter of
over nine-sixteenths of an inch. The berries were light blue in color,
and they ripened earlier than those of Brooks. This tendency toward
earliness appears in all the progeny of the Russell blueberry and is of
great commercial importance because the earliest of the improved
blueberries often bring the highest prices.
FIRST BLUEBERRY HYBRIDS
The first cross-pollinations between Russell and Brooks were made in
the spring of 1911. Some of the resulting first-generation hybrids
were cross-pollinated with each other in 1913. The resulting progeny,
about 3,000 hybrids of the first and second generations, was grown
to maturity in the field, with remarkable results.
The outstanding characteristic of these hybrids was the variation
in the color of their fruit. The berries of both Brooks and Russell
are of light blue color. The body of the berry in both varieties is a
dark purple, which appears as a black when the bloom is rubbed off.
In the first-generation hybrids of Brooks and Russell the bloom was
much thinner than in either parent, and in consequence the berries
of the hybrids were dark blue in color, in strong contrast with the light
blue berries of both parents. One of these first-generation hybrids
is shown in figure 2. When two of these dark-berried first-generation
hybrids were interbred the resulting second-generation hybrids
showed a still more remarkable diversity of color. On about 65 per-
cent of the plants the berries were dark blue, just as in the first-gen-
eration hybrids. On about 18 percent they were black, some of them
a dull black, some without a trace of bloom, so that the berries had
the shining appearance of a black shoe button. On about 15 percent
of the plants the berries were light blue, like the berries of both grand-
parents. On about 1.5 percent the berries were albinos. They
lacked the purple coloring matter that, located in the skin of the blue-
berry, gives the fruit the black color that appears when the bloom is
rubbed away. Further comments on these albino blueberries are
given later in this paper under the varieties Redskin and Catawba.
On about 0.5 percent of the plants the heavy bloom of the berries on
the two grandparents was replaced by an apparently still denser and
lighter colored bloom which gave the berry a metallic luster like that
of new aluminum ware.
A shining black color in these blueberry hybrids was never found
associated with a delicious taste, perhaps because there was not a
564
YEARBOOK, 193?
sufficient number of such plants to afford an adequate range in flavor.
The same was true of the "aluminum" berries. In the dark-colored
berries excellent flavor and good size were often combined. These
Figure 2. — One of the first blueberry hybrids. This is a first-generation cross be-
tween a wild highbush blueberry, Brooks, and a wild low bush blueberry, Russell,
from Greenfield, N. H. Another hybrid of the sanie parentage, 394Y, was one of
the ancestors of the varieties Kancocas, June, and Weymouth. (Natural size.)
dark-berried bushes of 2- to 3-foot stature are of frequent occurrence
in New England pastures as natural hybrids between Vaccinium
corymbosum and V. angustijolium. Such a hybrid is the plant
described in Gray's Manual of Botany and Rehder's Manual of Cul-
BLUEBERRIES 565
tivated Trees and Shrubs as V. corymbosum amoenum.3 About
Greenfield, N. H., the plants of such hybrids are popularly known as
the half-high blueberry. For many years I regarded this plant as a
distinct species, until it appeared by hundreds among the artificial
hybrids. _ „
Sooy Blueberry
An important step forward in blueberry breeding came about by
enlisting the interest of wild-blueberry pickers in New Jersey through
cooperation with Elizabeth C. White, of N ew Lisbon, N. J. On July 20,
1911, I stopped at the house of Ezekiel Sooy, an experienced picker
of wild blueberries, living at Browns Mills. It had been stipulated
that a wild blueberry, to be valuable, must be half an inch in diameter.
Mr. Sooy said that he hadn't any half-inch blueberries for me, that all
the good, bushes had berries much larger than that. He proceeded
to take me to one of them, near the road, a mile east of his house.
The berry proved to be a beauty, five-eighths of an inch in diameter.
I started to arrange that a portion of the bush be taken up later when
the plant was dormant, but Mr. Sooy took hold of a rooted sucker
about an inch in diameter and ripped it from the ground with a
forceful yank. I had been in the habit of treating blueberry plants
with consideration and when I protested that the plant had been
taken up neither at the proper season nor in the proper manner, Mr.
Sooy said, "That root will grow. You can't kill a blueberry bush."
So the top was cut off and the root was wrapped in a wet newspaper
and taken to Washington, where under the name Sooy it became one
of the progenitors of some of our best blueberry hybrids.
Brooks and Sooy were cross-pollinated in 1912. Nearly 3,000
seedlings of this parentage were grown to maturity in the field.
Among them were two plants that when propagated from cuttings
became the improved blueberry varieties Pioneer and Katharine.
THOUSANDS OF PEDIGREED SEEDLING BLUEBERRIES
TESTED TO OBTAIN 15 NAMED VARIETIES
Up to the year 1936 about 68,000 pedigreed blueberry seedlings
have been fruited and carefully examined to determine which were
sufficiently valuable to be propagated and distributed as named
varieties. The ancestry of each seedling is a matter of record. In
the testing plantations it was sometimes evident from the character-
istics of an individual plant that it did not belong to the group indi-
cated by the record. Somewhere during its life, when it was placed
in the ground as a seed, or when it was potted in the greenhouse, or
when it was packed for shipment, or when it was placed in the field
nursery, or when it was set in its final place in the testing field, it was
exchanged with another plant that had a different history. It hap-
pens, however, that none of these evidently misplaced plants has
proved to be of such high quality that it deserved to be named. We
are able to say, therefore, that the ancestry of our named varieties of
improved blueberries is above suspicion.
a Gkay, A. manual of botany of the northern united states. Ed. 6, 760 pp., illus. New York
and Chicago. 1890
KEHDEK, A. MANUAL OF CULTIVATED TREES AND SHBUBS HAKDY IN NORTH AMERICA, EXCLUSIVE OF THE
subtropical AND warmer temperate REGIONS. 930 pp., illus. New York. 1927.
566 YEARBOOK, 1937
TESTING BLUEBERRIES
The selection of the few best plants in a field containing thousands of
individual pedigreed blueberry seedlings is a tedious business. It
requires sustained attention and keen and repeated observations. As
one walks down the rows, the desirable color of an exceptionally light-
blue berry can be observed almost at a glance. If, however, the
branches of the plant are unusually flexible, the wind swaying a
heavy cluster of berries against a neighboring branch may wipe away
the bloom and disfigure the berries by leaving them black on one side.
Stiffness of branch is needed to insure uniformity in the color of the
berries.
To be sure of the size of a blueberry, one's judgment needs to be
checked continually with a gage. The gage illustrated in figure 3
was in use for several years until its largest hole, 25 millimeters (an
inch is 25.4 mm), was found to be too small to measure the largest
hybrid blueberry. This is the one described later in this paper as
GM37 and illustrated in figure 4. The original Brooks blueberry
slightly exceeded 14 mm, the Russell blueberry 15 mm, and the Sooy
blueberry 16 mm. Our largest hybrid that has a delicious flavor has
thus far attained only 24 mm in diameter.
The ease of picking and the size of the scar on the blueberry where
it separates from its stem are important. A small and dry scar is
the most desirable, and such a scar is usually associated with ease of
picking. Further notes on difficulty of picking are given later under
the variety Katharine, and on ease of picking under the variety
Rancocas. An undesirable feature was observed in some of the seed-
lings when the joint at the base of the stem of the individual berry
separated more easily than the joint at the upper end of the stem, and
the stem therefore remained attached to the berry when it was picked.
Such a berry is undesirable commercially.
In many of the seedlings the skin at the base of the blueberry tends
to remain attached to the stem and, in picking, a piece of skin is torn
from the berry. A seedling bearing such berries is always rejected,
however good its flavor and other qualities.
The keeping quality and the firmness of flesh must be considered in
selecting a blueberry, because under commercial conditions berries
without these qualities may not reach the consumer in good condition.
A blueberry is often rejected if it has a very large calyx. Such a calyx
may afford a place for an insect to hide.
Occasionally the ripe fruit of a blueberry tends to crack after a rain.
The crack may come between the calyx lobes, where the skin is some-
times tightly stretched as the berry enlarges and ripens, or it may form
about the middle of the berry. Several blueberries of large size and
delicious flavor have been rejected because of their tendency to crack.
Testing for Flavor
Probably the most elusive and difficult thing to judge in a new
blueberry is its flavor. After several hours of tasting, all blueberries
taste alike, and they all taste sour. On a day in which many blue-
berries are to be tried for flavor, I never swallow the berries I am
tasting, and I taste only those that appear promising from their size
BLUEBERRIES
567
and other visible qualities.
Even with such precautions to
conserve one's ability to dis-
tinguish flavors, it sometimes
is necessary to stop work in the
field until one's organs of taste
have recovered their faculty of
discrimination. If a blueberry
is to be eaten in a pie, its flavor
is of secondary importance, for
if it has not sufficient acidity a
teaspoonful of vinegar, or its
equivalent in lemon juice, will
supply the deficiency; but if
the blueberry is to be eaten
as a fresh fruit, either out of
hand or with cream and sugar,
its flavor, its seedlessness, and
its succulence are its chief con-
tributions to enjoyment.
A blueberry is sweet, slightly
sweet, or quite without sweet-
ness. It may be sour, slightly
acid, or flat. It may have
none of the special flavor of
the blueberry, or a little of it,
or this flavor may be present
in a high degree. Its flesh may
be lacking in juiciness, or it
may be juicy and sprightly.
When taken directly from the
bush, the blueberry varies in
taste with its degree of ripe-
ness. When blueberries first
turn blue they usually are still
sour. When they have been
blue about a week they com-
monly are ready for picking,
but the berries of some of the
varieties with relatively sour
fruit may need to remain on
the bush for 2 or even 3 weeks
after they turn blue, before
they become really palatable.
Figure 3. — A blueberry gage, the holes
from 7 mm (a little more than a
quarter of an inch) to 25 mm (a little
less than an inch) in diameter. The
largest blueberry thus far grown is a
little larger than the largest hole in
this gage.
568 YEARBOOK, 1937
Individual preferences vary regarding the taste of blueberries.
Some persons prefer a blueberry so sour that it cannot be eaten without
liberal quantities of sugar. My own preference is for a blueberry
that is juicy, sweet, with a slight acidity, and with the characteristic
blueberry flavor highly developed. If such blueberries are sound, and
for about 2 days after picking, can be kept in a shady, breezy place,
without refrigeration, preferably until they have begun to shrivel very
slightly, they are then in their ideal condition for flavor, and are ready
to go into the refrigerator for chilling before they are served.
In the field it has seemed difficult to find a satisfactory flavor in a
blueberry on a very hot day. Whether the fault is with the blueberry
or with the taster I cannot say. In tasting blueberries in the field, one
may easily make an error of judgment if the berry he tastes is blue but
not really ripe. If the berry is in an underripe condition it will have
a purplish color around the scar where it separated from its stem. If
the berry is of normal color and is fully ripe the area around the scat-
will be of the same color as the rest of the berry.
To avoid the introduction of new blueberry varieties that are
chiefly valuable to the grower only, because of their productiveness
and their shipping quality, it has been the aim of the Department, in
its blueberry breeding, to consider the consumer also, and especially
to develop for his benefit varieties of high flavor. As evidence of the
faithfulness of this endeavor it may be recorded that more than 300
seedling blueberry plants that bore berries over three-quarters of an
inch (19.1 mm) in diameter have been destroyed because they did not
come up to the standards we have set for flavor.
PROPAGATING NEW VARIETIES
When a seedling is of such high quality that it is considered worthy
of propagation and distribution as a new and named variety, single
buds taken from it are inserted, in midsummer, near the base of new
shoots that have grown from older blueberry plants cut to the ground
in the preceding winter. In the following spring each shoot is cut off
just above the inserted bud, and no other bud is allowed to grow. By
the end of the season the plant has a top of nearly the same size as
the top that was cut off two seasons before, aud this new top furnishes
many cuttings of the new variety. By this procedure a new variety
of blueberry can be propagated many times more rapidly than if the
cuttings were taken directly from the single original plant.
THE IMPROVED VARIETIES OF BLUEBERRY
Pioneer
Pioneeh was so designated because it was the first named variety
developed as a result of blueberry breeding. It was a first-generation
cross between the wild highbush blueberries Brooks and Sooy,_madein
1912. Like all the improved varieties not otherwise described, its
leaves have no teeth on their margins. Its berries are of light blue
color, sweet, of excellent flavor, and when fully ripe are without
acidity. The largest berry on the original bush was 18.5 mm in
diameter. Young Pioneer plants in commercial fields have borne
berries up to 19.7 mm. Pioneer is a midseason variety.
BLUEBERRIES 569
Greenfield
Greenfield was a second-generation hybrid between Brooks, a high-
bush blueberry, and Russell, a lowbush blueberry, both of them wild
plants from Greenfield, N. H. The leaves of Greenfield were finely
toothed. The seed from which the plant was grown came from a
cross-pollination made in the spring of 1913. The variety never
became established in commercial blueberry culture, and is recorded
here only for the purpose of accounting for the name.
Cabot
The Cabot blueberry is a first-generation hybrid between two wild
highbush blueberries, Brooks, already described, and Chatsworth,
which was found near the settlement named Chatsworth, in the pine
barrens of New Jersey. The cross-pollination was made in 1913.
The bush was named for my son, Cabot Coville, now secretary of
the American embassy at Tokyo, who chose this bush for the flavor
of its berries, which have a slight acidity, in preference to the sweet,
nonacid berries of Pioneer. Cabot is an early variety, for many years
the earliest of the named varieties, and in consequence it has been
planted very extensively by blueberry growers. It has been found
desirable to pick its berries about twice a week, and a bush sometimes
yields as many as seven pickings. The berries on the original bush
reached a diameter of 18.5 mm. For some obscure reason the fruit
buds of the Cabot blueberry, in late winter, are a morsel fascinating to
deer. At the blueberry plantation known as the Ore Ponds, a few
miles west of Toms River, N. J., the deer almost denuded the Cabot
bushes of their fruit buds in the early spring of 1928. In consequence
of this excessive priming by deer, the remaining buds produced berries
up to 20.5 mm in diameter, an unusually large size for this variety.
Katharine
The Katharine blueberry is of the same parentage as Pioneer. It
was a first-generation cross between the wild highbush blueberries
Brooks and Sooy, from a pollination made in 1913. The berries are
light blue and of especially delicious flavor. On the original bush
they reached a diameter of a little over 19 mm. Occasionally in
commercial plantations they reach 20 mm. The Katharine is hard to
pick. The berry clings tenaciously to its stem, and when it is pulled
away a hole is often torn in the base of the berry. The injury detracts
from both the appearance and the keeping quality of the berries, yet in
spite of this defect the Katharine is a variety that has been very satis-
factory to the consumer. The Katharine is named after my daughter,
Katharine, now Mrs. Chester C. Woodburn, of Des Moines, Iowa,
who in one of her high-school years did all my blueberry pollinations.
The variety ripens a little later than Pioneer.
Rancocas
One of the parents of Rancocas was an unnamed blueberry hybrid
known as 394 Y, a first-generation cross between Brooks and Russell.
The other parent was a wild blueberry from the pine barrens of New
Jersey named Rubel. This is, in form, the German spelling of the
138004°— 37 37 +4-
570 YEARBOOK, 1937
name of the old Russian coin, the rouble. The name of the blueberry
variety Rubel, however, is of neither German nor Russian derivation.
The man who discovered this bush was Rube Leek. Rube did not
seem an expressive name for a berry that was blue and beautiful, and
Leek was suggestive of a flavor that the berry did not possess. Rubel
was a compromise, made \ip of Mr. Leek's first name and the initial
of his last. The seed from which the Rancocas bush grew was the
result of a pollination in the spring of 1915. Rancocas is a second-
early variety, ripening its berries later than Cabot and earlier than
Pioneer. The original bush bore berries up to 18 mm in diameter.
Berries in commercial plantations sometimes exceed 19 mm. Rancocas
tends to the production of heavy crops on young and healthy bushes,
so heavy indeed that unusual care must be taken to prune the bushes
severely in order to insure a good crop in the following year. The
leaves of Rancocas have finely toothed margins. The berries have a
small, dry scar and are very easily picked. The name of this variety
came from Rancocas Creek in New Jersey. Near this creek was the
blueberry plantation in which the variety gave its first satisfactory
performance. ,
1 Jeusey
The variety Jersey was so named because both its parents were
wild plants from New Jersey. These parents were Rubel, already
described under Rancocas, and Grover, discovered by Russell Grover.
The two were cross-pollinated in 1916. _ Jersey is a variety maturing
late in the season, so late in fact that its berries often bring a high
price, in northern plantations, because of its lateness. This and other
late varieties extend the blueberry-picking season over a period of
about 8 weeks, the early varieties beginning to ripen in New Jersey in
the latter part of June and the late varieties continuing until the
middle of August and sometimes later. The berries of Jersey are
large, up to 22.4 mm in diameter, and, until dead ripe, too acid for
the taste of most persons. Jersey is of remarkably robust growth,
the leaves on vigorous shoots sometimes attaining a length of 4 inches
and a width of 2V4 inches. „
Concord
The Concord blueberry was so named because of its large clusters of
berries, which, all ripe at the same time, resemble clusters of Concord
grapes. It is a first-generation hybrid between the wild highbush
blueberries Brooks and Rubel and came from a cross-pollination in
1917. The original bush bore berries up to 18 mm in diameter. In
field culture its berries sometimes reach a diameter of 20 mm, occa-
sionally 21 mm. Concord berries are delicious when tliey are allowed
to remain on the bush until they are fully ripe and have lost the
excessive acidity they possess when they first turn blue. Concord is
a midseason variety, ripening at about the same time as Pioneer.
JUNE
June, named for its early ripening in New Jersey, is of the same
parentage as Rancocas, but from cross-pollinations made in 1919. On
the original bush the berries reached a diameter of 20 mm. In com-
mercial plantations they have sometimes exceeded 21 mm. The berry
BLUEBERRIES 571
is of medium blue color, sweet and delicious when fully ripe, with a
slight subacidity. It usually ripens earlier than Cabot. Although
June is of one-fourth lowbush ancestry, its leaf margins do not have
the teeth that characterize its lowbush grandparent.
Scammell
The Scammell blueberry is named for H. B. Scammell, of Toms
River, N. J., who first showed how good are the qualities of this berry
under field conditions. One of the parents of the Scammell was a
cross between the wild blueberries Brooks and Chatsworth. This
Brooks-Chatsworth parent, which was never planted in the field, was
recorded in the greenhouse in Washington as having "berries of
delicious taste, sweet, slightly acid and of pronounced flavor." This
plant was pollinated with Rubel pollen in 1915, and the Scammell
blueberry was one of the resulting seedlings. In the field the original
bush of Scammell bore berries up to a diameter of 20.5 mm. On
budded plants in the greenhouse in Washington they reached more than
22 mm. The berries have a medium blue color, firm texture, and a
small scar, and the calyx is almost wanting. The leaves are smaller than
on most varieties of highbush ancestry, commonly 1% to 2 inches in
length and five-eighths to three-quarters of an inch in width. The
berries are sweet, subacid, and have a high degree of flavor. They
ripen in late midseason. Among New Jersey growers there has been
little planting of this variety, apparently from doubt regarding its
vegetative vigor. In North Carolina, however, at the Double Trouble
Company's blueberry plantation near Magnolia, it is regarded as one
of their best varieties. „
Stanley
The Stanley resulted from a cross between the Katharine blueberry
and the wild Rubel bush; made in 1921. By many persons Stanley is
considered the most delicious of all blueberries. The original bush
bore berries a little less than 18 mm in diameter. From the first its
berries were recognized as of especially delicious flavor. It is named
for my son, Stanley, on whose blueberry plantation at New Lisbon,
N. J., this variety was first shown to be capable of producing good
yields of berries of large size. Its berries often exceed 19 mm in diam-
eter and sometimes 20 mm. In one instance a Stanley berry reached
a diameter of 21 mm and in another instance 22 mm. The Stanley
blueberry is a late midseason variety.
Redskin
The Redskin blueberry is an albino, a second-generation hybrid
between the wild highbush blueberry Brooks and the wild lowbush
blueberry Russell. The original Redskin plant came from a pollination
made in 1913. Albino blueberries become red on the side exposed to
the sun. In the Redskin blueberry the red is almost that of old mahog-
any, with only a trace of bloom. The berry sometimes exceeds 16 mm
in diameter, and the flavor is good. The berry ripens early in the
season. This variety and the next, Catawba, were given names in
1932 because as red-cheeked albinos they are horticultural curiosities.
The fair size and good flavor of their berries make them desirable
additions to a collection of blueberry varieties for a home garden. It
572 YEARBOOK, 1937
is doubtful whether any albino blueberry will ever acquire importance
as a market fruit. The white color of the shaded half of the Redskin
berry gives the fruit a mottled appearance after picking, and on any
slight bruise the injured portion of the flesh turns to a dried-apple
color, both of these features making the fruit uninviting to a purchaser.
The leaves of Eedskin are finely toothed. This variety should be
pruned at the end of the growing season by the removal of all the
stems that fruited in the preceding summer, only the season's sprouts
being left. When so pruned, Eedskin hardly reaches a height of 2
feet. This low stature, which allows the plants to be kept covered
with snow very easily during the bitter cold of a northern midwinter,
suggests Eedskin as a desirable variety in places so far north that other
and taller varieties project through the snow and lose their fruit buds
by winter-killing. _,
J & Catawba
The Catawba blueberry is an albino which was bred from the same
grandparents and the same parents as Eedskin, and in the same year.
The berries of Catawba are not so large as those of Eedskin, nor is
their flavor quite so good. They have more bloom, and the red of the
berry is therefore paler than in redskin, more like the color of the
Catawba grape, a resemblance that suggested the varietal name. The
leaves of the Catawba are finely toothed, and the plants reach a
height of about 4 feet. wr
& WAREHAM
In the autumn of 1916 some 300 pedigreed but untested blueberry
seedlings were sent to the cranberry substation of the Massachusetts
Agricultural Experiment Station, East Wareham, Mass., to be brought
into fruit by H. J. Franklin, in charge of the cranberry substation.
Among these seedlings was one that, after several years of observa-
tion, Professor Franklin thought was of sufficient merit to be named
and distributed. In accordance with his wish it was named Ware-
ham. The parents of the Wareham blueberry were the wild New
Jersey highbush blueberry Eubel and another wild New Jersey high-
bush blueberry named Harding, after its discoverer, Ealph Harding.
The cross-pollination was made in 1915. The original bush of the
Wareham blueberry, in the late summer of 1931, had a breadth of 9
by 9 feet and a height of 6 feet. It was vigorous and had produced 8
quarts of berries that season. It differed from most other tall vari-
eties of blueberries improved bj breeding in having serrate leaves, like
its Harding parent. When I saw the bush again, on July 28, 1933,
its berries had not yet been picked. Several were over 19 mm in
diameter, some of them nearly 20 mm. Wareham is a late-season
variety, its berries maturing at about the same time as Jersey. Until
they are dead ripe they are a little too acid for the taste of most per-
sons. When fully ripe they are sweet-subacid and of good flavor.
Weymouth
The Weymouth is named for the cranberry and blueberry planta-
tion of Weymouth, at which most of the Department's testing of new
pedigreed blueberry seedlings has been conducted since 1929, between
Hammonton and Mays Landing, N. J. It is near Weymouth Fur-
nace, long ago abandoned, at which cannon and cannonballs were
BLUEBERRIES 573
made from bog iron ore during the War of 1812. The Weymouth
blueberry is a cross between the two early varieties June and Cabot,
The pollination was made in 1928. Although the earliness of Wey-
mouth is not yet satisfactorily proved from commercial field experi-
ence, the original bush bore berries that reached nearly 22 mm in
diameter and ripened much earlier than Cabot. The berries have
only a moderate degree of acidity in the early stage of their ripening,
and they are sweet, subacid, and delicious when they are first picked.
They lose much of their taste if they are allowed to become overripe.
GM37
There is one seedling blueberry that, although barred from commer-
cial culture because its berries are deficient hi flavor, has other such
desirable qualities, including the extraordinary size of its fruit, that
acquaintance with this unnamed bush ought to be shared with the
public. It is known in our records as GM37. It is a cross between
Jersey and Pioneer, and therefore has four wild highbush ancestors,
Grover and Rubel, the parents of Jersey, and Brooks and Sooy, the
parents of Pioneer. The pollination from which GM37 came was
made in 1925. The original bush produced berries hi 1928 over 20
mm in diameter, in 1929 over 21 mm, and in 1930 nearly 23 mm. In
1933 a budded bush of GM37, hand-pollinated and screened, in a
New Jersey blueberry plantation, produced berries up to 25.9 mm, a
little over an inch, in diameter. (An inch is 25.4 nun.) A cluster of
berries from this bush is illustrated, natural size, in figure 4. The
reader should bear in mind that this is the largest bhic berry ever pro-
duced, but it lacks the flavor required to warrant making it a named
variety. For breeding purposes, however, GM37 has great value, as
will be evident from what is said under the next variety, Dixi,
Dim '
The unnamed blueberry GM37 lacked only flavor to make it a
valuable variety. In 1930 it was cross- pollinated with the Stanley
blueberry, the most delicious of all varieties. Among the progeny
was a bush that attracted attention first, in 1935 and again in 1936.
Its berries are sweet-subacid and delicious. On July 9, 1935, the
largest beriy was over 21 mm in diameter, and on Jidy 24 of that
year over 23 mm. On July 24, 1936, the largest berry reached 24
mm. If the season of 1936 had been a favorable one for the develop-
ment of large individual blueberries, I am confident that the berries
on this plant would have reached a diameter of more than an inch.
There is now only a single bush of this variety.^ It will bo several
years before it can be propagated for a thorough field test of its qual-
ities. Nevertheless, there are circumstances that seem to make it desir-
able to give a name to this variety at this time. Toward the end of
the present fiscal year I terminate my connection with the Depart-
ment of Agriculture after 49 years of botanical research. It was the
custom of Linnaeus and other scientific men of his time, when a
* Blueberry growers should he careful not to misspell! ho name of the, nisi blueberry, for the wrong spell-
ing "Dixie" may give the erroneous impression that this variety is especially adapted to cultivation in the
South. The ancestors of the Dixi blueberry were, northern plants, and although tho variety may be of
value as far south as North Carolina, there is every reason to expect Unit it will not thrive in the Oulf States.
574
YEARBOOK, 1937
public address was given in Latin, to end the address with a Latin
word that meant "1 have spoken," "I have said what I have to say,"
or "I am through." Therefore, with orthographic apologies to the
southern half of the United States, I name tins blueberry and end
this paper with that Latin word — Dixi.
Figure 4. — A cluster of the largest blueberries thus far grown. (Natural size.)
The largest berry on this bush was 25.9 mm (a little more than an inch) in
diameter. This bush, known in our records as CM37, was not made a named
variety because its berries were not up to our standard of flavor. It has been
cross-bred, however, with the most delicious variety of blueberry, Stanley. Among
the off-spring is the large and delicious blueberry described in this paper as Dixi,
which already, as a young plant, has produced berries nearly as large as those
shown in this illustration.
PROGRESS IN
APPLE IMPROVEMENT
J. R. MAGNESS, Principal Pomologisl ,
Division of Fruit and Vegetable Crops
and Diseases, Bureau of Plant Industry '
J. HE apple we have today is far removed from Hie "gift of the
gods" which prehistoric man found, in roaming the woods of western
Asia and temperate Europe. We can judge that apple only by the
wild apples that grow today in the area between the Caspian Sea
and Europe, which is believed to be the original habitat of the apple.
These apples are generally only 1 to 2 inches in diameter, are acid
and astringent, and are far inferior to the choice modern horticultural
varieties.
The improvement of the apple through the, selection of the best
types of the wild seedlings goes far back to the very beginning of
history. Methods of budding and grafting fruits were known more
than 2,000 years ago. According to linger, Cato (third century,
B. C.) knew seven different apple varieties. Pliny (first century,
A. D.) knew 36 different kinds. By the time the lirst settlers from
Europe were coming to the shores of North America., hundreds of
apple varieties had been named in European countries.
The superior varieties grown in Europe in the seventeenth century
had, so far as is known, all developed as chance seedlings, but garden-
ers had selected the best of the seedling trees and propagated them
vegetatively.
The early American settlers, particularly those from the temperate
portions of Europe, who came to the eastern coast of North Amer-
ica, brought with them seeds and in some cases grafted trees of
European varieties. Within a few years after the first settlements
were made in the temperate portions of North America, bearing apple
trees were reported.
From this start, apple trees were rapidly disseminated. The apple
was apparently carried by Indians, traders, and missionaries into the
wilderness far beyond the white settlements. In the early writings
frequent mention is made of Indian villages with apple and peach
1 This article is made possible only through the oooporal ion of many workers on apple brooding in both tho
United States and Europe. Reports on which portions of this discussion are based have, beon received from
the following State agricultural experiment station workers: Lcif Verncr, Idaho; M. J. Dorscy, Illinois;
J. L. Lantz, Iowa; R. M. Bailey, Maine; A. L. Schradcr, Maryland; J. K. Shaw, Massachusetts; W. H.
Alderman, Minnesota; Paul 11. Shepard, Missouri; Hlato l.''ruit. Experiment Station; A. E. Murneok, Mis-
souri; Richard Wellington and CI. H. Howe, Now York (State) Station; F. S. ITowlclt and O. W. Ellenwood,
Ohio; N. E. Hansen, South Dakota; Fred W. HofMann, Virginia; also from W. 1'. Baird, U. S. Northern
Great Plains Field Station, Mandan, N. Dak.; C. P. Close, V. S. Department; of Agriculture, Washing-
ton, D. C; T. F. Ritchie, acting Dominion horl iculturist, Central Experimental Farm, Ottawa,
Canada; Sir Daniel Hall, director, John Innes Horticultural Institution, Morton, England; Carl O. Dahl,
Lantbruks, Mejeri-och Tradgiirdsinstitut, Alnarp, Sweden; lug. Fr. Landovsky, Stale Institute for
Horticultural Research, Pruhonice, Czechoslovakia; Prof. Dr. Utidorf, Kaiser Wilhclm Inst.if.ut fiir
Ziichtungsforschung, Miincheberg, Germany; and 11. Wcnholz, Department of Agriculture, Sydney , New
South Wales, Australia.
575
576 YEARBOOK. 1937
orchards adjacent to them; apparently the Indians were an important
factor in the early dissemination of these fruits. All the Indian
orchards consisted, of course, of seedling trees. Since the apple does
not come true from seed, wide variations in size, color, and quality
of fruit and season of ripening undoubtedly occurred in these early
orchards. As the country became more settled, farmers and gardeners
were interested in growing the best of these seedlings rather than
in planting a miscellaneous assortment that could be secured from
It is uncertain just when the first grafting of apple varieties was
practiced in the United States. Taylor (IS, pp. 808-309) 2 says:
Certain it is that in 1647 the apple is recorded as grafted upon wild stocks in
Virginia, while in 1686 William Fitzhugh, in describing his own plantation,
mentions "a large orchard of about 2,500 apple trees, most grafted, well fenced
with a locust fence." * * * Frequent importations of seeds, scions, and
grafted trees, together with propagation from those already noticed, both by
seeds and grafts, brought the orchards of New England up to such point that
Dudley, in 1726, stated in a paper in the Philosophical Transactions, "our Apples
are without doubt as good as those of England, and much fairer to look to, and so
arc the Pears * * * Our People of late years, have run so much upon
Orchards, that in a village near Boston, consisting of about forty Families, they
made near ten Thousand Barrels [of cider]."
:Italic numbers in parentheses refer to Selected References to Literature, p. 001.
APPLE breeding is a task that requires not only great patience
but ability to look well into the future. In most sections of the
United States at least 10 to 15 years are required to grow an apple
front seed to bearing age and to obtain an accurate evaluation of it.
To propagate and test a promising kind will require an additional
10 to 12 years. Therefore not less than 25 years are usually re-
quired from the time a cross is made until the progeny of that cross
can be fully evaluated. Additional years must then elapse before
commercial orchards come into fruiting. Thus it usually takes
from 30 to 40 years between the planting of the original seed and
the production of commercial crops of even a very superior apple.
Apples originating from the earliest breeding investigations in the
United States, begun as far back as 1880, are just now coming
into prominence; those from the breeding work of 20 or 25 years
ago are not yet fully tested. It is easy to see, then, why few of our
popular commercial varieties have as yet resulted from modern breed-
ing work. However, there is every prospect that varieties superior to
those now in use will result from the many thousands of hybrid
seedlings now under test at various research centers.
APPLES 577
As settlements spread westward to the Mississippi Valley and on to
the Pacific, apple planting kept pace. An eccentric missionary, John
Chapman, known as "Johnny Appleseed", roamed the frontier settle-
ments of Ohio and Indiana in the early nineteenth century, planting
apple seed and starting orchards wherever he went and encouraging
others to do the same. He lived to see bearing trees throughout the
area. Thus the fepple became more or less naturalized throughout the
temperate part of North America.
The apple varieties grown here today are quite largely those that
have been developed from the seedling trees that happened to be
superior. Only a few of our important commercial varieties have been
imported from Europe. During the past century the primary em-
phasis in the United States has been on varieties with superior dessert
and cooking quality, along with good size, a range of ripening from
midsummer to late fall, and a storage quality that will carry the fruit
through the winter months. Perhaps the greater emphasis in Europe
on the use of apples for cider making is partially responsible for the
smaller number of really high-quality dessert apples selected there.
Table 1, in the appendix, indicates the source of leading American
varieties of apples so far as it is known.
Pew of the apples that have reached commercial promise to date
have been produced as a result of systematic hybridization. The
reason for this is readily apparent when certain of the factors involved
in apple breeding are considered. Practically no systematic work was
started in the United States prior to 1880, and little was carried on
prior to 1895. In most sections of the United States at least 10 to 15
years are required to grow an apple tree from seed to bearing age and
to give an accurate evaluation of it. To propagate and test a promis-
ing kind will require an additional 10 to 12 years. Therefore not less
than 25 years is usually required from the time a cross is made until
the progeny of that cross can be accurately evaluated. Additional
years must then elapse before commercial orchards come into fruiting.
Thus from 30 to 40 years will usually elapse between the planting of
the original seed and the production of commercial crops of even a
very superior apple. Apples originating from the earlier breeding
investigations are just now coming into commercial prominence.
Since much of the breeding work has been conducted during the last
20 or 25 years, sufficient time has not yet elapsed to give a full evalua-
tion of the offspring of the crosses made.
THE RAW MATERIALS OF THE APPLE BREEDER
The apple belongs to the great family of plants termed by botanists
the Rosaceae, or rose family. This family is very large and includes
many tree fruits of the Temperate Zone, such as plums and prunes,
peaches, cherries, apricots, and pears, as well as strawberries, black-
berries, and many other forms of cultivated and wild plants. Apples
and pears belong to the pome fruit subfamily Pomoideae, which in-
cludes, in addition to these fruits, the hawthorns, _ cotoneasters,
quinces, medlars, mountain-ash, and a number of additional related
forms. All of the plants in this subfamily are characterized by having
the seeds borne in a fleshy covering and having two to five carpels, or
seed cavities, in each fruit. Within the Pomoideae the genus Mains,
578 YEARBOOK, 1937
comprising the apples, makes up one important group. Many
botanists have included the apple in the pear genus, Pyrus. The
fruits of these two groups are distinguished by the fact that the pears
contain grit cells, while the flesh of the apple is free of grit cells.
There are also other distinctive differences in the structure of certain
flower parts.
The various species that make up the genus Malus' can in most cases
be hybridized rather readily. Species of Mains apparently do not
hybridize readily with species of Pyrus or with those of other genera
in the Pomoideae. No such crosses have been reported, although
there has been ample opportunity for them to occur naturally in view
of the wide distribution and adjacent plantings of many members of
these genera.
There is some difference of opinion among botanists as to whether
one or more than one species originally entered into the parentage
of our cultivated apple. The wide diversity of existing forms has
led some students to believe that several species were involved origi-
nally. However, this diversity might well be expected in a fruit crop
selected and cultivated for thousands of years and propagated largely
by vegetative means. Every interesting variation occurring in seed-
lings could thus be preserved.
In addition to the cultivated apple, Rehder, in his Manual of Cul-
tivated Trees and Shrubs, lists 24 species of apples or crab apples,
native mainly in China, Siberia, Japan, and the United States. Bailey
in his Manual of Cultivated Plants makes a somewhat different divi-
sion, listing 25 species of Malus. Knowledge of the close relatives
that might be expected to hybridize readily with the cultivated apple
is of much interest from the breeding standpoint.
While these species represent basic raw material available to the
apple breeder, for most purposes it is not desirable to use the original
types in breeding work. The selection of superior varieties through
the centuries has given us breeding material that is far more promising
than the parent species for the development of superior new kinds by
hybridization. Only when special characters, such as extreme hardi-
ness, are needed does it seem more desirable to \ise original species
material. For the production of crab apple types and for ornamental
purposes, however, these species are of outstanding value.
OBJECTIVES IN AMERICAN APPLE BREEDING
Objectives in the apple-breeding work vary, of course, in different
sections. Throughout most of the apple belt in the United States
increased winter hardiness is highly desirable, and in the colder sec-
tions, including the northern Great Plains area and northern New
England, it is the all-important factor in apple production. A few
varieties such as Mcintosh, Wealthy, Oldenburg, and Yellow Trans-
parent are_ sufficiently hardy for all but the northernmost part of the
Plains region. Many important varieties, including Baldwin, Stay-
man Winesap, Winesap, Grimes Golden, Rome Beauty, Yellow New-
town, and Jonathan, may be severely injured or trees may be killed
during severe winters in many sections of the country. Increased
hardiness must continually be sought in the apple-breeding program
for all but possibly the southeastern districts.
APPLES 579
The second most important objective is greater disease resistance.
The five diseases that cause the greatest loss of apples in the United
States are scab, blotch, bitter rot, fire blight, and apple cedar rust.
There are wide degrees of susceptibility to all of these diseases. No
commercial variety is immune from scab. However, Mcintosh, De-
licious, Stayman Winesap, and Rome Beauty are far more subject to
the disease than are Grimes Golden, York Imperial, Baldwin, or
Jonathan. Similarly, Golden Delicious, Yellow Newtown, Grimes
Golden, and Jonathan are extremely subject to bitter rot, and for this
reason they are of doubtful value for planting in the far southeastern
districts. On the other hand, Winesap, Baldwin, Delicious, Rome
Beauty, Stayman Winesap, and York Imperial are relatively resistant
to this disease.
Varieties very susceptible to blotch include Ben Davis, Mcintosh,
Northwestern Greening, and Oldenburg, while a list of relatively
resistant varieties includes Delicious, Grimes Golden, Jonathan, Stay-
man Winesap, and York Imperial.
Baldwin and Delicious are highly resistant to apple cedar rust,
while Jonathan, Rome Beauty ? Wealthy, and York Imperial are quite
susceptible. Seedlings of resistant parents show a high degree of
resistance to this disease, while seedlings of susceptible parents are
highly susceptible.
Fire blight is a serious orchard disease of Yellow Transparent,
Jonathan, Wealthy, York Imperial, and a number of other varieties.
On the other hand, Delicious, Ben Davis, and the Winesap family of
varieties are resistant. We know that seedlings of Yellow Transparent
tend to be susceptible, but we have little information as to how the
characters of susceptibility or resistance to fire blight or other diseases
behave in hybridization.
Susceptibility to spray injury also is an important character from
the standpoint of evaluating a variety for commercial use. Golden
Delicious and Ben Davis are particularly susceptible, while many
varieties, including Delicious, Mcintosh, Rhode Island Greening,
Rome Beauty, Stayman Winesap, and others, show little injury.
The securing of new varieties fairly resistant to all of these diseases
and to spray injury is a distinct possibility. It should be a primary
objective in breeding, and all new selections should be studied from
the standpoint of disease susceptibility.
The third objective, important in many parts of the United States,
is the securing of late-blooming varieties that will have a greater
possibility of escaping spring frosts and freezes. In most apple
sections spring frosts or freezes are likely to reduce the apple crop
greatly in certain years. In some sections this may run as high as 2
years in 5, in other sections perhaps not over 1 year in 10. Varieties
blooming a week to 10 days later than standard types would have an
increasingly better chance to escape such losses. This is particularly
important in some of the midwestern areas. The late-blooming
character is present in Rome Beauty, Mother, Ralls, and some other
varieties, and through the use of such varieties in breeding, late-
blooming trees can be obtained.
A fourth objective is the securing of varieties having highly
developed, rich flavor combined with desirable tree characters.
580 YEARBOOK, 1937
Among highly flavored varieties are Delicious, Golden Delicious,
Esopus Spitzenburg, Jonathan, Grimes Golden, and Mcintosh.
Many of these have horticultural weaknesses such as lack of hardi-
ness, disease susceptibility, insufficient tree vigor, and susceptibility
to spray injury.
It is desirable to obtain high-quality, attractively colored varieties
that 'will be available throughout the year through the use of cold
storage. Improvement in color in our present varieties is being accom-
plished by selection of attractive, highly colored bud mutations. On
the average our long-keeping varieties are inferior in quality to those
that are available earlier in the season, such as Mcintosh, Grimes
Golden, and Jonathan.
Another important objective is the development of varieties adapted
to the far South. At present there are no satisfactory varieties for
the region within 200 miles of the Gulf of Mexico. Native crab apples
might be of value for hybridizing to produce varieties adapted to
that region. No active work of this kind is under way, but there is
a real need for it. Until apples can be grown locally, many people
in that region will never have an adequate supply of the fruit.
The relative importance of these different objectives varies in
different regions. In the Southeastern States disease resistance is of
major importance. In the northern Plains area winter hardiness
becomes the most important single objective. In the Missouri and
Ohio Valleys, late blooming to escape the hazards of spring frost
assumes major importance. Throughout all of the regions a suc-
cession of high-quality varieties available for use throughout the year
is highly desirable.
METHODS OF IMPROVEMENT BY SELECTION
OF BUD MUTATIONS
Occasionally cell division in the vegetative tissues fails to reproduce
a new cell exactly like the parent. The result is an occasional branch
or bud that varies in some respect from the parent tree on which it is
borne. Such a mutant branch or bud normally reproduces true when
propagated vegetatively, provided the variation is a true mutation
and has not been caused by environmental conditions.
The fact that such bud or branch mutations occasionally occur has
long been known to plant propagators. It is only in recent years,
however, that the importance of these variations, from the standpoint
of improving our fruit varieties, has been fully appreciated.
During the past decade an intensive search of American apple
orchards has been conducted to locate such mutations as may be of
value. Since red-colored apples command a considerable premium on
the American markets, imitations carrying a greater amount of red
color have been particularly sought. How successful the search has
been is indicated by the fact that we now have more than 30 red strains
of the Delicious variety. Many of these red strains, however, may
prove to be so similar as to be practically indistinguishable. More
than 15 red strains of Rome Beauty are known, 20 strains of Winesap,
8 strains of Stayman Winesap, and several strains of Mcintosh, York
Imperial, Jonathan, and other leading varieties. At the present time,
strains believed to color earlier or to have better color are in existence
APPLES 581
for practically all of the leading red or blushed apple varieties. In
several varieties, namely, Delicious, Rome Beauty, Winesap, Jonathan,
and Stayman Winesap, new commercial plantings are largely of the
improved strains rather than the standard varietal forms.
It has been assumed by many nurserymen and growers that in
general such mutations vary from the parent in only one character.
This is not necessarily true. Variations in season of ripening, fruit
size, storage quality, dessert quality, or productiveness may accom-
pany color variations. Therefore the various bud mutations should
be thoroughly tested before they are widely propagated commercially.
In addition to mutations affecting color, a few have been found that
involve season of maturity, size, shape, and flavor of fruit. It is of
course obvious that variations in flavor, storage quality, or produc-
tiveness are less likely to be located than are variations of color or
season of maturity, which are very conspicuous when the fruit is still
on the tree.
A search for bud mutations is especially likely to lead to rapid
results in the improvement of horticultural varieties. Generally
these mutations mean only a slight difference in varieties that have
already proved themselves excellent from a commercial standpoint.
For example, the Winesap apple is already established as a leading
commercial variety. Its greatest weakness is its tendency to rather
small fruit size and lack of tree vigor under all but the best soil condi-
tions. Its growing season is too long to permit proper development
of the fruit in northern districts. Thus, bud mutations of Winesap
that would give an earlier ripening apple would extend the range north-
ward. Similarly, a mutation showing larger size of fruit would be of
much value. A search for such mutations should be continued in
American orchards.
The process of selection, propagation, and testing of bud mutations
perhaps offers a possibility for more rapid improvement of our present
desirable varieties than does any other method of breeding. Possibly
by bud selection we might find a later maturing Mcintosh adapted
for growing farther south than the present Mcintosh belt, or an
earlier maturing Stayman Winesap, Rome Beauty, or Winesap, which
would mean better adaptation to northern sections. The fact that
color can be improved by the use of such selections has already been
amply demonstrated. The testing of bud mutations should be an
integral part of the variety-improvement program in the years to
come. For originating definitely new types of apples, however, or
for the incorporation of new characters, such as greatly increased hardi-
ness or vigor, hybridization appears to offer the greater possibilities.
HYBRIDIZATION OF APPLES AND PEARS
There is no unusual difficulty in the technique of hybridizing apples
and pears. Several steps of this technique are illustrated in figure 1.
The flower parts of an apple or pear, in order, from the outside of the
blossom to the center, are as follows: (1) The calyx, consisting of 5
sepals at the base of the blossom; (2), the corolla, made up of 5 white
or pink petals; (3), the stamens or pollen-bearing organs, usually 20
in number, which are borne just inside the petals; (4), the pistil, the
central organ that contains the seeds. In hybridizing most varieties
582
YEARBOOK, 1937
it is desirable to remove the pollen-bearing stamens from the Mower
before it opens. The best time to do this is at the so-called balloon
stage^ illustrated in figure 1, A, while the petals still form a complete
covering over the inner flower parts. At that stage the stamens have
not yet begun to shed pollen and there has previously been no oppor-
tunity for either self- or cross-pollination to occur.
Two methods may be employed in removing the pollen-bearing
organs. In the method shown in the figure, the thumbnail or a small
u4nfAef
,- -Petal
Stamen
Figure 1. — Steps in hybridization of apples and pears: A,. Bud in proper stage for
emasculation; B, after emasculation, showing petals, sepals, and stamens pinched off
and removed; C, an open flower, showing the flower parts that are removed in
emasculation; D, the method of protecting emasculated flowers from chance 2>ollination.
knife or a laboratory scalpel is used to make a cut just at the base of
the sepals. The flower part is then bent sidewise, and the whole
flower organ except the pistil can be torn loose, as shown in figure 1 , B.
If carefully done, this loaves the pistil, consisting of the ovary contain-
ing the seeds, with a cluster of styles and stigmas, as shown in B.
The tearing loose of the flower parts may result in enough injury to
reduce the set of fruit. In the second method, which is somewhat
slower but less likely to cause injury, the petals are pulled loose at the
stage shown in A, and the anthers are picked out of the blossom with
an instrument ; an ordinary comb is satisfactory.
If the flowers are within a day or two of opening when emasculated,
it is satisfactory to apply the pollen of the selected male parent at the
APPLES 583
time the emasculation is done; or the application of pollen may be
postponed for a day or two. The pollen should be applied, however,
before the stigmas begin to turn brown. The emasculated blossoms
must be protected from chance pollination for several days. A satis-
factory method is shown in figure 1, D.
A higher percentage of set of fruit will usually result if not more
than two blossoms are emasculated and pollinated in a cluster. The
remaining blossoms • should, of course, be picked off at the time
the emasculating is done.
Handling the Pollen
To secure pollen, buds in the stage shown in figure 1, A, are picked
and the anthers combed out of them as described above. If these
anthers are held in a moderately warm, dry place they will ripen rather
rapidly and begin to shed pollen within 24 to 48 hours.
Sometimes branches of the desired pollen parent are brought into
a room or a greenhouse before the blossoms open, set in water, and
allowed to bloom protected from insects. The pollen is removed from
the open flowers when it is ripe.
Pollen is usually applied to the stigmas of the emasculated blossoms
with a fine camel's-hair brush, which may be sterilized between
pollinations by washing in alcohol or immersing for several seconds in
boiling water. After the pollen has been applied, the emasculated
blossoms should again be protected (fig. 2). When conditions are
favorable, from 30 to 50 percent of the emasculated blossoms should
set fruit. After the stigmas have turned completely brown the
protecting bags may be removed and labels designating the cross should
be carefully adjusted. The fruit may be harvested when slightly
immature to prevent undue loss from dropping. Germination of the
seed is not affected by such early harvesting.
Handling the Fruit and Seeds
Two or three alternative methods may be used for handling the fruit
and seeds after harvest. Since apple and pear seeds must go through
certain transformations, often described as "resting" or ''after ripen-
ing," before they will germinate, the fruit may be placed in cold or
cellar storage and held until spring. The seeds can then be removed
and immediately planted in nursery rows. An alternative method of
handling is to remove the seed from the fruit after harvest, place it in
small labeled bags, and put these in cold storage over winter. It is
necessary that the seed be sufficiently well dried and that it be stored
in a sufficiently dry place to prevent it from molding, but excessive
drying should be avoided. A third method is to stratify or bury the
seed and carry it over winter outdoors. If facilities are available, the
seed may be planted in flats in the greenhouse or in coldframes and the
seedlings allowed to grow 3 or 4 inches high before being transplanted
to nursery rows in the field, but this is not necessary.
After 2 years in the nursery row the apple seedlings may be trans-
planted to the orchard, sufficient space being allowed to permit the
trees to come into fruit. Pear trees can be planted at somewhat
closer distances in the orchard than apple trees ; they will usually fruit
satisfactorily if planted about 4 feet apart in the row, with the rows
581
YEARBOOK, 1937
*>*V *
-*_ ■*!:■%
Figure 2. — Cross-pollinated apple blossoms protected under glassiuc bags and labeled.
about 15 feet apart to facilitate cultivation and spraying. Apple
trees should have at least 10 feet of space in the row, with rows 15
feet apart, if the fruiting value of the young trees is to be adequately
determined.
To speed up the testing and at the same time conserve space, buds or
grafts from young seedling trees may be put into older trees growing in
APPLES 585
orchard form. Several buds or grafts may be put into an apple tree
4 to 6 years old. Usually it is preferable to have only seedlings of the
same parentage worked on one orchard tree. If such a tree is main-
tained in good vigor and if the budding or grafting is satisfactorily
accomplished, fruiting records should be obtained within 3 to 4 years
from the date of budding or grafting. Usually budwood or scions from
the seedlings can be obtained at the end of the first growing season.
Thus, by this method, an indication of fruit value with apples or pears
can be obtained in about 5 years from the time of making the cross.
If the seedlings themselves are grown to fruiting age in the orchard, 8
to 10 years will usually be required. However, growing the seedling
itself to fruiting permits a better evaluation of the tree from the stand-
point of vigor, hardiness, disease resistance, and tree form.
In using the budding or grafting method, it is desirable to have trees
that are not too old. Young orchard trees 4 to 5 years old are most
nearly ideal from the standpoint of top-working, and they are small,
enough to facilitate the work of taking records on fruiting branches.
Several steps in apple breeding as carried on at the New York Agri-
cultural Experiment Station at Geneva are illustrated in figures
3, 4, and 5.3
Significance of Unusuai, Chromosome Numbers
It is only within the last 10 years that we have had definite informa-
tion on the chromosome numbers of the various apple varieties.
This has clarified our understanding of the behavior of varieties,
particularly from the standpoint of pollination and breeding. We
now understand the reasons for the peculiar behavior of certain vari-
eties long observed in the orchard.
Investigators have known for some years that certain varieties are
poor pollinizers for others. They do not form much good pollen,
most of the grains being abortive and failing to grow when put in a
sugar solution suitable for pollen germination. Usually when these
varieties are planted alone or in blocks with others of similar type,
poor sets of fruit are secured. Among the varieties known as poor
pollinizers are Stayman Winesap, Baldwin, Rhode Island Greening,
Gravenstein, Arkansas (Black Twig), Tompkins King, Stark, and
several less important ones.
These varieties have certain other characteristics in common also.
All produce large-sized fruit, and all are vigorous growers and develop
into large trees. Nursery investigations have indicated that as a rule
seed produced by these varieties germinates poorly and the seedling
trees are usually weak growers.
Our present knowledge of the number of chromosomes in apple
varieties has been contributed by many investigators in many coun-
tries, including V. A. Rybin, in the Union of Soviet Socialist Republics ;
A. A. Moffett, M. B. Crane, W. J. C. Lawrence, and C. D. Darlington,
in England; J. S. Shoemaker and B. R. Nebel, in the United States;
F. Kobel, in German y; O. Heilborn, in Sweden; and others. These
workers have shown "that most of the cultivated varieties of apples
have 34 chromosomes (17 pairs) in the vegetative or somatic tissues,
and 17 (one member of each pair) in the germ cells. These A'arieties
3 From photographs furnished hy the station.
lnsnO't"— p,7 ss
586
YEARBOOK, 193 7
Figure 3. — Steps in apple breeding: A, Collecting pollen from unopened clusters; B,
blossoms emasculated and ready for the application of pollen (note that the pollen-
bearing organs have been removed); C, applying pollen to the pistils of the emasculated
flowers; D, pollinated flowers protected from chance pollination by covering with
paper bags; E, mesh bags used to protect the fruit that has set; F, seeds resulting from
controlled pollination, protected by mouse-proof screen for stratifying in soil.
APPLES
Figure 4. — Steps in apple breeding; A, Young seedling trees grown in flats
prior to setting in the field; B, planting of young hybrid trees in orchard form; C, a
hybrid orchard in fruiting. At this stage undesirable seedlings can be eliminated.
588
YEARBOOK, 1937
with 34 diploid chromosomes as a rule produce fertile pollen and they
are generally classed as good pollinizers for other varieties. The
trees vary in vigor from low to moderately high, and fruit size varies
from small to large.
The peculiarity of the second group of varieties, described above
as being partially or in some cases almost entirely pollen-sterile and
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Figure 5. — Second tests of promising hybrid selections.
is Early Mcintosh.
The tree in the foreground
producing large fruit and large vigorous trees, is that they have 51
chromosomes instead of 34 in the somatic tissues. They are termed
triploids,4 since the chromosome number in the vegetative tissue is
three times that of the usual reproductive cells of apples, instead of
twice, as in the diploids.
« This is discussed by A. F. Blakeslee in his article in this Yearbook.
APPLES 589
The question arises, How have these triploid varieties developed?
Normally the cells of the vegetative tissue have only twice as many
chromosomes as the reproductive cells. How can we account for
the considerable number of apple varieties that carry three times this
basic chromosome number?
It is not known definitely how the triploid forms developed. At
long intervals, the frequency varying with different species, a germ
cell in either the male or the female organs may be developed with
an extra set of chromosomes. Experimentally, cells are occasionally
formed with double the normal number of chromosomes as a result of
subjecting them during the process of germ-cell formation to unusual
environmental conditions, such as high or low temperatures. It may
be deduced, therefore, that at rare intervals under natural conditions
pollen grains or egg cells are formed that carry 34 rather than 17
chromosomes in the reproductive cells.
Now if an egg cell carrying 34 chromosomes is fertilized by a sperm
carrying 17 chromosomes, the resulting fertilized egg will have 51
chromosomes. It will develop into an embryo and ultimately into
a plant carrying 51 chromosomes in its vegetative tissues. If such
a tree is propagated vegetativery, the result is a horticultural variety
with 51 chromosomes instead of the normal 34.
Approximately one-fourth of all commercial apple varieties are these
triploid or 51-chromosome forms. Yet it is probable that such forms are
rarely produced among seedling apple trees. ' For example, in all of the
controlled breeding work that has been done in the United States,
involving crosses of diploid X diploid, diploid X triploid, triploid X
diploid, and triploid X triploid, no seedling of merit known to be
a triploid has been produced. It is apparent, therefore, that in nature
triploid forms are produced only rarely as compared to diploids.
How, then, can we account for the fact that at least a fourth of our
important varieties are triploids? This is possible only if we assume
that the triploids have characteristics that make them of unusual
value as commercial varieties, so that an unusually high proportion
of the triploid forms have been selected and propagated as varieties.
It is probable that in the United States in the last 250 years more than
200,000,000 apple trees of seedling origin have grown and fruited.
Even if only 1 in 50,000 of these was a triploid, it would mean that
several thousand triploid trees have grown in the United States some
time during the past two and a half centuries. If these trees on the
average had certain superior characteristics as compared with the
hundreds of millions of diploid trees, they could easily have become
the source of a relatively large number of improved varieties. Some
of their characteristics of unusual value from a commercial standpoint
have already been enumerated, namely, large size of fruit and vigorous
growth and large size of trees. Heilborn (.9) has also pointed out that
most of the triploid varieties grown in Europe have relatively long
storage quality. This does not apply to all of the xVmerican triploid
varieties, but many of them are firm-fleshed apples of good storage
quality. Thus it seems probable that from the mass of seedling
material available in the United States and Europe a relatively high
proportion of the rare triploids has been selected and a relatively
small proportion of the more common diploids.
590 YEARBOOK, 1937
Can We Breed for Triploid Varieties?
These points of superiority of the triploid varieties would indicate
that attempts should be made to secure triploids in breeding. It is
true that a large portion of the seedlings produced in breeding work
tend to run to medium or small fruit size. This tendency could un-
doubtedly be corrected if triploid varieties could be obtained at will.
Unfortunately, however, this cannot be done.
As explained above, crossing of diploid X diploid varieties normally
gives only diploids. What occurs when we cross diploids X triploids
or triploids X triploids?
The triploid somatic or vegetative cells contain 51 chromosomes —
34 obtained from one parent germ cell and 17 from the other. In the
pairing of the chromosomes, which takes place prior to the formation
of germ cells, 34 will pair normally into 17 pairs. But the remaining
17 of the 51 chromosomes are not arranged in any special order, and
they are unable to pair among themselves. After pairing, the chromo-
somes again divide, half going to one pole of the nucleus and half to
the other pole. But the 17 unpaired chromosomes cannot do this in
an orderly fashion. Some of them go to one pole and some to the
other at random. Thus, when the cell finally splits in half to form
two germ cells, we find that each of these contains 17 chromosomes
from the original pairs and an indefinite number of other chromosomes
from those that had not paired. This indefinite number varies all
the way from none at all to the whole 17 unpaired chromosomes.
Such a germ cell may have any number of chromosomes from 17 to 34.
The great majority of these germ cells with an irregular chromosome
number are sterile. The addition of chromosomes above the normal
number but less than double the number seems to result in sterility
to a large extent throughout the plant kingdom. In apples, however,
some viable pollen grains are found in most of the triploid forms, and
in most varieties enough of the egg cells are sufficiently fertile to give
a satisfactory fruit set, particularly if they are pollinated with diploid
pollen.
However, when the egg cell containing 17 to 34 chromosomes is
fertilized with a nucleus from diploid pollen containing 17 chromo-
somes, we usually will have neither diploid nor triploid offspring.
The number will vary from 34 to 51, that is, 17 from the pollen cell
plus 17 to 34 from the egg cell. These are called aneuploids, and the
seeds generally germinate poorly. Those that do grow are likely to
?roduce weak seedlings, though occasionally they are fairly vigorous,
t is of interest to note, however, that of the varieties that have been
introduced as a result of breeding work in the United States to date,
none has a parent of known triploid constitution. This is in line with
cytological studies on many species of plants, which indicate the
slight probability of obtaining promising varieties when one or both
of the parents are triploids.
Triploids crossed with triploids also are likely to give aneuploid
progeny. Here the possible number of chromosomes will range from
34 to 68 and may be expressed numerically by the formula [17+
(0 to 17)] + [17+(0 to 17)]. Such triploid X triploid progeny are
likely to be weak vegetatively if they grow at all.
APPLES 591
In order to obtain triploids at will in breeding, it is necessary to
have a tetraploid parent (four times the basic number) to cross with
a diploid. We do not now have any apple or pear varieties that are
known to be tetraploids. There is a possibility _ that tetraploids
resulting from chromosome doubling in some cell in the vegetative
tissues originate at rare intervals as bud sports or somatic mutations
in normal diploid varieties. One or two mutations that may be of this
type have recently been found in pears, though their nature has not
yet been definitely determined. If similar mutations can be found in
apples, they will be of great interest from the breeding standpoint.
Such bud sports will probably be characterized by giant fruits, since
the character of giantism is often associated with chromosome
doubling. Giant strains of apples, occurring as bud sports, should be
carefully preserved until their character can be determined, even
though the fruit itself may appear to be of no value.
Aside from diploid and triploid varieties, a word should be said as
to the chromosome make-up of the genera Mains and Pyrus. These
genera and other closely related forms stand out among the Rosaceae
in having 17 chromosomes in the reduced phase (the reproductive
cells), whereas the basic number in other genera of the family is
mostly 7 and in a few 8 or 9. In Mains and Pyrus the 17 chromosomes
are believed to represent multiplication from the simpler base of 7, 8,
or 9, either by hybridization or by polyploid mutations. This com-
plex chromosome constitution of apples and pears may account for
the fact that there is such wide variation in selected varieties within
these species, that mutations both in seed reproduction and vegetative
tissues occur fairly frequently, and that most selected varieties are
highly heterozygous, failing to reproduce seedlings closely resembling
the parent.
INHERITANCE OF TREE AND FRUIT CHARACTERS
Most of our apple varieties are highly heterozygous, or mixed in
their inheritance. This fact, coupled with the long time required to
grow a generation, the impossibility of successfully selfing most
varieties, and the relatively small populations that can be grown,
makes the working out of inheritance factors difficult. The following
summation is taken mainly from Wellington (17), Auchter (2), Lantz
and Bole (12), and Crane and Lawrence (6).
Triploid X triploid or triploid X diploid varieties produce generally
weak trees if seeds grow, because of aneuploid chromosome make-up.
Among diploid X diploid crosses, weak growth appears recessive to
vigorous growth.
Tree shape — spreading, round, or upright — appears to be due to a
number of genes. Forms of hybrids are usually intermediate between
parents, with the progeny tending to be more nearly round than a
strictly intermediate form would be.
Age of bearing is undoubtedly inherited, but simple segregations
have not been obtained. Late-bearing and early-bearing parents
tend to transmit these tendencies.
Susceptibility to apple cedar rust, to blight, and to scab appears
to be inherited, but httle is known of the segregations involved.
592 YEARBOOK, 1937
Date of fruit ripening follows parent behavior closely. Late-
ripening parents give late-ripening progeny; early -ripening parents,
early-ripening progeny ; and early X late crosses usually ripen between
the ripening dates of the two parents. In fruit size, large size seems
dominant over small, but the factors are complex. Small crab apples
crossed with apples give intermediate sizes. Most large apples carry
some factors for small. To secure large size, cross large X large.
Large X small fruit sizes yield progenies that are usually intermediate.
Crane and Lawrence found the average of the progeny to be somewhat
smaller than the average of the two parents.
Yellow or green skin color usually behaves as a recessive, though
occasional red apples will appear in yellow X yellow hybrids. Appar
ently a number of factors are involved in color. Blush X blush parents
may occasionally give deeper reds than either parent.
Flesh texture appears to follow parent type to a considerable degree,
but some coarse-fleshed progeny are produced by tender-fleshed
parents. Several factors appear to be involved in flesh texture, as
well as in flesh color.
In flavor, sweet (lack of acidity) appears to be recessive. Some
highly acid varieties, as Boiken, Oldenburg, and Montgomery, seem
to be homozygous, or "pure" in their inheritance, for acidity. Mildly
acid varieties give some sweet progeny and appear heterozygous for
sweetness. Acid X acid gives a considerable proportion of progeny
with acidity accentuated beyond either parent.
APPLE BREEDING IN THE UNITED STATES
A relatively large program of apple breeding is now under way in
the United States, with active projects at 12 experiment stations and
work at two points by the United States Department of Agriculture.
The past and present workers in apple breeding are listed in the
appendix. (See table 4.) In table 3 are summarized the crosses
made at the stations that have fruited to date, together with the
number of progeny from each cross considered to have horticultural
promise, either as varieties or for further breeding work.
In the following pages, the work at the various stations is briefly
summarized. T
Idaho
At the Idaho Agricultural Experiment Station, Moscow, breeding
was begun in 1909 by C. C. Vincent, and since then 11,824 hybrid
seedlings have been planted in orchard form . Results have indicated
that the Jonathan, Wagener, and Esopus Spitzenburg varieties have
tended to give highest dessert quality. Ben Davis crosses have the
highest percentage of seedlings showing good keeping quality. No
varieties have yet been introduced to the trade, but 101 selections
have been made for detailed study.
Illinois
Since the work was started at the Illinois Agricultural Experiment
Station, Urbana, in 1908 by C. S. Crandall, approximately 15,000
trees have been fruited in the orchard, and detailed records have been
made of the characteristics of the fruit produced. In the earlier work,
a large number of crosses were made between cultivated varieties and
APPLES
593
various species of crab apples. Later, the emphasis has shifted to
hybridizing commercial varieties containing the qualities desired.
The primary objective in the early breeding work was to secure data
on genetic behavior of the apple. This is being continued, but greater
emphasis is now placed on the securing of high dessert quality and
good keeping quality in new varieties. At the present time, almost
3,000 seedlings representing high-quality parents are being grown.
The principal varieties used in this later Weeding work include Akin,
Delicious, Jonathan, Golden Delicious, Maiden Blush, Fameuse,
Winesap, Fanny, Grimes Golden,
and Rome Beauty. In breeding
for early apples of good quality,
Yellow Transparent is being
crossed with high-quality stand-
ard-season varieties.
From the seedlings that have
fruited, 338 promising selections
are being held for further observa-
tion as to their commercial value.
No varieties have been named.
Iowa
Apple-breeding work in Iowa
was begun bv C. G. Patten (fig. 6)
at Charles City about 1867. Pat-
ten began as an independent fruit
breeder but later received some
financial assistance from the Iowa
State Horticultural Society. From
1909 to 1914 the United States De-
partment of Agriculture assisted in
the work. In 1916 the State pur-
chased the farm and fruit-breed-
ing materials and the station was
operated by the Iowa Agricultural
Experiment Station until 1932. Patten introduced several varieties-
Patten, Eastman, Brilliant, Silas Wilson, Iowa Beauty, and University.
A number of selections from his work are still being used by the Iowa
station.
Work in fruit breeding and variety testing was begun at the Iowa
Agricultural Experiment Station, Ames, about 1880, by J. L. Budd.
The primary objective was to secure varieties of fairly good quality
that would be hardy and productive under the severe winter conditions
existing in Iowa. A large number of Russian varieties were intro-
duced between 1880 and 1890 and tested at Ames. Most of these
were not of desirable quality although many were extremely hardy.
The inherent hardiness of this group of apples suggested their value
for breeding. That they transmit their hardiness to their seedlings
has been amply demonstrated by the work at the Iowa station since
1917. Budd grew seedlings of many open-pollinated fruits during the
period from 1882 to 1905. Fruiting records were not made, and the
results of this earlier work are not available. In general, results were
Figure 6.— Charles G. Patten (1832-1921),
a pioneer breeder of hardy apples, pears,
and plums at Charles City, Iowa.
594
YEARBOOK, 1937
not sufficiently good to warrant continued work with open-pollinated
seedlings.
The cross-breeding work in apples was initiated by S. A. Beach
(fig. 7) in 1905, and large numbers of crosses were made between 1906
and 1910. Further breeding work was not attempted until the crosses
were fruited. The seedlings began to fruit in 1916 and were described
and the results tabulated by H.
L. Lantz, T J. Maney, and others,
under the direction of Beach.
In an effort to bring theseedling
trees into fruiting as early as pos-
sible, top-working was practiced,
with three to five different seed-
lings worked on suitable stocks.
While top-working was found to
promote earlier bearing, several
difficulties developed. Some
scions failed to make satisfactory
growth because they were too
heavily shaded by more vigorous
neighbors. Records were diffi-
cult to make because of confusion
as to location of each graft on the
tree. The growth habit of the
tree could not be satisfactorily
determined on top-worked ma-
terial. In later work, therefore,
the practice of top-working was
discontinued. The varieties that
have been introduced to date as a
result of the breeding work at the
Iowa station are listed in table 2
in the appendix.
After most of the crosses made
by Beach had fruited, additional
crossing was started and has
been carried on with little inter-
ruption. At the present time,
about 13,000 seedlings are being grown to fruiting from crosses made
since 1917. A considerable number of these are now fruiting. A
summary of the parentage of these seedlings is published in the
Transactions of the Iowa State Horticultural Society, 1935.
Maine
Breeding work was begun at the Maine Agricultural Experiment
Station, Orono, in 191 1 , but no records of the earlier work are available.
Approximately 1,000 seedlings of crosses of Mcintosh, Golden Deli-
cious, Delicious, Northern Spy, Wealthy, and Cortland are now grow-
ing in nursery rows. Additional crosses involving the above varieties
and Haralson and Scott Winter have been made during the past year.
The objectives in this work are to secure hardy, high-quality vari-
eties adapted to New England.
figure 7. — Spencer Ambrose Beach (1862-
3922). As head of the horticultural work
at the New York (State) Agricultural Ex-
periment Station from 1891 to 1905, and at
the Iowa Agricultural Experiment Station
from 1905 to 1922, he laid sure foundations
for the splendid work of both stations in
the breeding of fruit crops.
APPLES
595
Chromosome counts have been made on several apple varieties.
The following apparently are diploids: Ben Davis, Oldenburg, Early
Harvest, Golden Delicious, LaRue, Mcintosh, Milden, Northern
Spy* Opalescent, Porter, Red Astrachan, Golden Russet, Chenango,
Tolman Sweet, Wealthy, Wolf River, and Yellow Transparent.
Varieties showing irregular chromosome numbers, probably triploids,
FigurcS. — The fruits of breeding: Apple orchards in the Shenandoah-Potoniac
Valley section.
include Baldwin, Gravenstein, Rhode Island Greening, Rolfe, and
Stark.
Maryland
Breeding work at the University of Maryland, College Park, was
started in 1906. The objective at first was to produce early-ripening
red varieties of good quality. A total of 1,073 seedlings were grown
prior to 1917. In this group of seedlings, 13 were selected as promising.
Since 1929, a limited number of seedlings have been grown as a result
of seed produced in pollination work. Three hundred and fifty-eight
seedlings, representing crosses of good-quality main-season varieties,
are now growing in the experimental orchard. Typical western
Maryland apple orchards are shown in figure 8.
Massachusetts
At the Massachusetts Agricultural Experiment Station, Amherst,
a number of cross-pollinated seeds resulting from pollination work have
been planted from 1925 to date. These include crosses of Red
596 YEARBOOK, 1937
Astrachan with Cortland, Delicious, and Mcintosh; Mcintosh with
Cortland, Delicious, Northern Spy, and Macoun; Northern Spy with
Delicious, Mcintosh, and Wealthy; Gravenstein with Wealthy; and
Northern Spy selfed. , ,
ifJ Minnesota
Apple-breeding work supported by the State of Minnesota was
started in 1878, when an annual subsidy administered by the board of
regents of the university was granted to Peter Gideon for continuation
of his breeding work. Apple breeding organized by and completely
under the control of the Minnesota Agricultural Experiment Station
was begun about 1890, under the direction of S. B. Green. From 1890
to 1905 several thousand seedlings, largely of Russian varieties, were
grown. In 1907 about 4,000 seedlings of Malinda, open pollinated,
were planted in the field. About 300 of these have characteristics
either of hardiness or fruit quality of sufficient merit to be retained.
From 1907 to 1912 approximately 13,000 seedlings, many from con-
trolled crosses, were grown. In this group of material, 541 trees have
been retained for further study. Since 1918, 4,781 seedling trees of
hybrid parentage have been grown to fruiting in the breeding plots.
The principal crosses are listed in table 3 in the appendix. At the
present time, approximately 5,000 trees resulting from crosses made
from 1921 to date are being grown to fruiting.
The primary objective in Minnesota is the securing of varieties of
good quality that are hardy under the extremely cold winters of that
section. Several varieties introduced as a result of the breeding work
are fisted in table 2, in the appendix.
During the past 100 years a number of individuals have contributed
to the list of hardy varieties adapted to this section. The best known
of these, Peter Gideon, began planting seed in 1854. He introduced
the Wealthy, still one of the leading apple varieties of the United
States. Peter, Gideon, and Gideon Sweet were other varieties devel-
oped by him. Others in the State who have raised apple seedlings for
the specific purpose of developing hardy varieties include G. H.
Pond, of Bloomington; John Shaw, of Minnesota City; H. M. Lyman,
of Excelsior; Amasa Stewart, of Le Sueur County; Titus Day, of
Farmington; Henry Stubbs; and others. A relatively large number
of hardy apples have been named as the result of the efforts of these
men. ,,
Missouri
Apple-breeding investigations in Missouri are conducted both at the
Missouri State Fruit Experiment Station, Mountain Grove, and at
the University of Missouri, Columbia. Work at Mountain Grove
was started in 1901. In 1935 the six varieties listed in table 2 were
introduced.
The primary objective in the early breeding work at the Mountain
Grove station was to obtain good storage varieties well adapted to
growing conditions in Missouri. With this objective, the principal
varieties used included Ben Davis, Winesap, Jonathan, Ingram, and
Delicious.
In the breeding work since 1923, the primary objective has been to
produce late-blooming varieties with high quality. The principal
varieties used include Kails, Ingram, Mother, Northern Spy, Jona-
APPLES 597
than, Delicious, King David, and Golden Delicious. Since 1923,
1,821 seedlings of known parentage have been produced and are now
growing in orchard form. Most of these have not yet fruited.
At the University of Missouri, at Columbia, some apple-breeding
work has been conducted since 1905. The variety Whitten, from an
Ingram X Delicious cross made in 1905 by J. C. Whitten, was intro-
duced in 1925. This is a vigorous tree, a prolific bearer, and has
fruit above medium size, yellow blushed with red, and of good quality.
At the present time, 2,732 seedlings resulting from crosses made in
1931 and 1932 at the State Fruit Experiment Station are being grown
to fruiting at Columbia. This collection consists mainly of crosses of
King David, Wolf River, Ingram, Alexander, Ralls, Twenty Ounce,
Rome Beauty, Jonathan, Golden Delicious, Delicious, Mother;
Gravenstein, and Northern Spy.
New York
Breeding work with apples at the New York (State) Agricultural
Experiment Station, Geneva, was started in 1892, and since that time
over 13,000 apple seedlings have been set in the orchard for fruiting,
with nearly 2,000 additional now in the nurseries. Over 9,000 of these
trees have been set in the orchard since 1922, so the major part of the
seedlings have not yet been tested. In producing these 15,000 seed-
lings, 110 varieties, 10 species, and 63 seedlings have been used as
parents. Fifty-five varieties and seedlings have been self-pollinated,
but seedlings resulting from these self-pollinations have lacked vigor.
Varieties now known to be triploids, including Baldwin, Gravenstein,
Rhode Island Greening, and Tompkins King, have given only weak
and worthless progeny. Of the diploid varieties, crosses of Mcintosh
have given by far the greatest number of desirable seedlings. Crosses
of Northern Spy and of Yellow Newtown generally produce late-
maturing fruit. Yellow Transparent has given early-ripening vari-
eties tart in flavor. Delicious and Deacon Jones have given mostly
mild-flavored fruits. Results show that if large-fruited seedlings are
desired, large-fruited parents must be used. Sweet flavor appears to
behave as recessive, but it is usually impossible to predict just how
flavors will be transmitted.
Varieties used most extensively in the breeding work are: Bald-
win, 23 times; Cortland, 71; Deacon Jones, 26; Delicious, 38; Early
Mcintosh, 41; Gravenstein, including Red Gravenstein, 27; Kendall,
26; Macoun, 37; Mcintosh, 186; Milton, 31; Northern Spy and Red
Spy, 76 ; Oldenburg, including red sports, 39 ; Rhode Island Greening,
27; Rome Beauty, including red sports, 57; Wealthy, 32; Yellow New-
town, 30; and Yellow Transparent, 35.
The specific objective of the New York station is to obtain hardy,
good-quality apples for dessert and cooking that ripen throughout the
season. The most important single need is to secure a high-quality,
productive, late-keeping red variety that is [fully hardy under New
York State conditions. Tree characters desired include early bearing,
hardiness to cold winters, self-fruitfulness, sufficiently late blooming
to resist spring frosts, and resistance to insects and diseases.
A study of the chromosome constitution of varieties and seedlings
is an important part of the breeding program. Crossing of triploid
598 YEARBOOK, 1937
varieties or of triploid and diploid varieties has produced no new trip-
loid varieties. Chromosome counts on more than 100 resulting seed-
lings have been made, and all have been aneuploids; that is, having
chromosome numbers other than 34 or 5 1 . More than 1 ,000 such seed-
lings have been discarded for lack of vigor and fertility. Table 2, in
the appendix, lists the varieties introduced as a result of the breeding
work at the Geneva station.
There is no formal breeding project at the New York (Cornell)
station, Ithaca. At present, about 100 seedling trees of Mcintosh
crosses, obtained incidentally in pollination experiments, are being
grown to fruiting. ^
Apple-breeding work was begun at the Ohio Agricultural Experi-
ment.Station, 'Wooster, by J. B. Keil in 1915. During that year and
the year following, crosses were made from which 963 seedlings have
fruited. Of these, 25 have been selected for further study or for
further use in breeding.
Since 1929, some additional crosses have been made each year by
F. S. Howlett and C. W. Ellenwood. From these, 2,414 seedlings
are now being grown to fruiting. These later crosses are primarily
between Delicious, Mcintosh, Gallia Beauty, Northern Spy, Golden
Delicious, Cox Orange, Jonathan, Esopus Spitzenburg, Kails, Rome
Beauty, Mother, and some of the numbered selections that resulted
from the earlier breeding work. Table 2 in the appendix lists
five varieties recently introduced as a result of the breeding work in
Ohio.
The specific objectives include (1) to obtain late-blooming varieties
that will thus tend to escape the hazards of spring frosts and freezes,
and (2) to develop late-keeping varieties whose storage season will
extend from February until late spring. A considerable number of
seedlings that bloom later than Rome Beauty and Northern Spy, but
for the most part derived from these two varieties, have been obtained.
South Dakota
Breeding of apples and other hardy fruits has been a leading
horticultural project at the South Dakota Agricultural Experiment
Station, Brookings, since 1895. The primary objective is to obtain
fruits of fair to good quality that are hardy under the extreme winter
cold and frequent summer drought of the northern Plains area.
Fully 10,000 apple seedlings of various pedigrees have been grown
to fruiting. Much of this has been open-pollinated material.
Numerous hybrids between selections of wild crab apples and hardy
cultivated apple varieties have been made. As a result of this breed-
ing work, about 25 varieties of crab apples and a considerable number
of apples have been introduced. The apples, with their parentage
and characteristics, are listed in table 2, in the appendix. Crab
apples introduced include Alexis, Amur, Cathay, Beauty, Dolgo,
Hopa, Ivan, Izo, Kola, Linda, Maga, Mercer, Missouri Pippin,
Nocalyx, Olga, Red Tip, Sapinia, Shoko, Sugar, Tipi, Zapta, Red
Flesh, Wakonda, Zelma, Zita, Zaza, Bison, Caputa, Wanblee, Wau-
bay, and Amsib.
APPLES 599
Virginia
The apple-breeding program at the Virginia Agricultural Experi-
ment Station, Blacksburg, is not extensive. A number of open-
pollinated seedlings have been fruited, of which one from Mother,
one from Northern Spy, and three from Delicious appear to have
horticultural value. A number of crosses are being made to secure
late-blooming, high-quality, and highly colored varieties. Eight
hundred fifty-six seedlings of Ralls X Rome Beauty, 622 seedlings of
Ralls X Mother, and 1,234 seedlings of York Imperial open-pollinated
are now growing in the nursery row.
United States Department of Agriculture
A limited amount of apple breeding has been done by Department
of Agriculture workers. From 1912 to 1920, C. P. Close hybridized
early varieties with the objective of securing early good-quality
varieties in season with Yellow Transparent, or before, and preferably
carrying red color. The varieties used included Yellow Transparent,
Early Harvest, Early Ripe, Red June, and Red Astrachan. About
400 seedlings representing hybrids of these varieties have fruited in
the orchard.
A number of early -ripening selections have been made. Seven of
these selections, carrying red color and ripening with Yellow Trans-
parent or earlier, have been distributed for experimental testing.
Yellow Transparent has tended to be an excellent parent in the trans-
mission of shape, size, and season of ripening.
Approximately 500 seedling trees of crosses made from 1927 to
1929 are now coming into fruiting at the National Agricultural
Research Center, Beltsville, Md. These represent crosses of long-
keeping varieties made with the objective of securing good-quality,
long storage-season types. The principal parents include Winesap,
Yellow Newtown, Granny Smith, Vandervere, and Mcintosh.
Promising bud mutations of possible horticultural value originating
in various parts of the United States are being grown for comparative
testing at Beltsville. The oldest of these selections have now been
planted in the orchard 4 years. Additional plantings have been
made each year as additional material has been collected. Four
trees propagated from each mutation are grown in comparison with
parent varieties. In the orchard at the present time are the follow-
ing bud sports: Baldwin 3, Delicious 30, Gravenstein 5, Jonathan
4, Mcintosh 4, Northern Spy 3, Oldenburg 5, Rome Beauty 15,
Stark 2, Stayman Winesap 9, St. Lawrence 1, Summer Queen 1,
Twenty Ounce 1, Willowtwig 1, and Winesap 20.
Work to develop hardier and better fruits for the northern Great
Plains area has been in progress at the United States Northern Great
Plains Field Station, near Mandan, N. Dak., since 1915. A large
number of Wealthy and other apple and crab apple seedlings have
been grown. Several selections from these have been propagated
and are being given further test. None has as yet been named.
This method of growing quantities of apple seedlings of unknown or
partially unknown parentage has been discontinued during recent
years, and seedlings of known parentage are being produced at the
600 YEARBOOK, 1937
present time. About 10,000 apple trees of known parentage are
now growing, but only a small part of these have reached bearing
age.
A considerable amount of hybridizing between the Siberian crab,
Malus baccata (L.) Borkh., and standard apple varieties was done
in earlier years. These crosses have resulted in seedlings that are
hardy and vigorous but have generally small fruits. The varieties
being used most largely for hybridizing purposes include Wealthy,
Oldenburg, Red Duchess, Mcintosh, Delicious, Starking, Yellow
Transparent, Haralson, Anoka, and the crab apples Dolgo, Florence,
and Whitney. AppLE BREEDING IN CANADA
Bkginning in 1889, a major program was started to develop superior
apple varieties sufficiently hardy to withstand rigorous weather con-
ditions in all parts of Canada. At the Central Experimental Farm,
Ottawa, seed of Russian varieties planted in 1889 gave 3,000 trees.
From this work, only one variety worthy of mention developed —
the Rupert, an apple a little earlier than Yellow Transparent and
equal to it in quality.
The next step was the crossing of the Siberian crab with named
Russian and American apple varieties. Fruits of the first-generation
progeny were all under 2 inches in diameter. These, recrossed with
apple varieties, gave fruits up to 2% inches in diameter but lost some
of the hardiness of the first-generation hybrids. Most of the fruit of
the first-generation hybrids retained the crab characters — long, slender
stem; thin, tender skin; and firm, crisp, breaking flesh.
Cross-breeding with better varieties was begun in 1898. Since
then, 253 different combinations with 66 different varieties have been
made. The variety that has been outstanding as a parent is Mcintosh.
In one block of 159 trees from open-pollinated Mcintosh seed saved
in 1898, 27 varieties of sufficient promise for naming were developed.
Among these are Melba, Joyce, Macross, Hume, and Lobo. In more
recent years, Mcintosh has been crossed with the finest quality
varieties available. Much of this material has not yet fruited.
In addition to this work carried on at the Central Experimental
Farm, breeding is also conducted at the Ontario Agricultural College,
Guelph, Ontario, and at the Horticultural Experiment Station,
Vineland, Ontario. At Guelph, several thousand seedlings, repre-
senting mainly crosses of the Mcintosh, Northern Spy, Wealthy,
Wagener, and several other varieties, have been fruited. At Vine-
land, more than 8,000 seedlings have been grown since the work was
started in 1915. These represent 130 crosses between varieties, and
seed of 65 crosses and selections open-pollinated.
In more recent years the attempts to secure extreme hardiness
have been centered at experiment stations in the prairie Provinces,
namely, the University of Saskatchewan, Saskatoon, Saskatchewan,
and the Dominion Experimental Station at Morden, Manitoba. The
most extensive project is at the University of Saskatchewan. Prior
to 1930, more than a quarter of a million crosses of apples had been
made at that place. The female parents used have been the Siberian
crab and the hardiest of the hybrid crab apples such as Osman, Co-
APPLES 601
lumbia, Prince, Charles, Tony, and Magmis. The apple varieties
have included Mcintosh, Melba, Wealthy, Oldenburg, St. Lawrence,
and Yellow Transparent.
The largest collection in Canada of the hardiest varieties of apples
and crab apples is at the Dominion Experimental Station at Morden.
In 1916 some 27,000 open-pollinated seedlings from the hardiest
Russian and other varieties of apples were planted. Several thousand
of these have fruited, and many are being tested in the prairie
Provinces.
A limited amount of breeding work is under way at the Dominion
Experimental Station, Summerland, British Coluriibia. This work
consists of crosses of high-quality and long-storage apples. The
principal parents used are Mcintosh, Yellow Newtown, Winesap,
Delicious, Golden Delicious, Rome Beauty, and Grimes Golden. The
earliest of these seedlings are just coming into fruiting. Macoun
summarized the first 40 years of apple-breeding work in Canada,
with the comment that the time should not be far distant when there
will be varieties of Canadian apples suitable for all parts of that
country where farm development is possible. Experience with
breeding apples in Canada indicates the following conclusions,
according to Macoun (18):
(1) To originate extremely hardy apples:
(a) Cross the apple with the wild Siberian crab and reeross the hardiest Fi
with the apple.
(b) Sow seeds of apples that are hardy in other sections having severe
climatic conditions.
(2) To originate apples having hardiness, vigor, productiveness of tree, and
high quality, good size, and appearance, cross varieties having most of the char-
acteristics desired.
(3) In cross-breeding, where quality is an important factor, cross two varieties
that are both good or very good in quality. In crossing a variety of good quality
with one of inferior quality, the Fi will nearly always bear fruit of mediocre
quality.
(4) Use parents that have been found by other breeders to transmit their desir-
able characters to a large degree.
APPLE BREEDING IN EUROPE
The work of European agencies in apple breeding is summarized in
the appendix. This summary includes work with the other tree fruits
as well as apples, since in most cases several fruits are involved in a
single more or less unified breeding program.
SELECTED REFERENCES TO LITERATURE
(1) Alderman, W. H.
1936. ACCOMPLISHMENTS IN FRUIT BREEDING BY STATE AND PEDEKAL
experiment stations. Amer. Soc. Hort. Sci. Proc. (1935)
33: 13-20.
(2) Auchter, E. C.
1921. PRELIMINARY REPORT ON APPLE AND PEAR BREEDING IN MARYLAND.
Amer. Soc. Hort. Sci. Proc. (1920) 17: 19-32.
(3) Beach, S. A., assisted by Booth, N. O., and Taylor, O. M.
1905. the apples of new York. 2 v., illus. Albany. (N. Y. Agr. Expt.
Sta. Kept. 1903, pt. 2.)
(4) Crandall, C. S.
1926. apple breeding at the university of ILLINOIS. 111. Agr. Expt.
Sta. Bull. 275, pp. 341-600, illus.
138904°— 37 39 ++
602 YEARBOOK, 1937
(o) Crake, M. B., and Lawrence, W. J. C.
1930. FERTILITY AND VIGOUR OF APPLES Ii\T RELATION TO CHROMOSOME
number. Jour. Genetics 22: 153-163.
(6) and Lawrence, W. J. C.
1934. the genetics op garden plants. 236 pp., illus. London.
(7) Einset, O.
1930. cross-unfruitfulness in the apple. N. Y. State Agr. Expt.
Sta. Tech. Bull. 159, 24 pp.
(8) Hansen, N. E.
1927. plant introductions (1895-1927). S. Dak. Agr. Expt. Sta. Bull.
224, 4 pp., illus.
(9) Heilborn, O.
1935. reduction division, pollen lethality, and polyploidy in
apples. Acta Hort. Bergiani Proc. (1930) 27: 406-410, illus.
(10) Howlett, F. S.
1927. apple pollination studies in ohio. Ohio Agr. Expt. Sta. Bull.
404, 84 pp., illus.
(11) Kimball, D. A.
1931. A STUDY OF THE PROGENY RESULTING FROM CROSSING CERTAIN APPLE
varieties. Amer. Soc. Hort. Sci. Proc. (1930) 27: 412-415.
(12) Lantz, H. L., and Bole, S. J.
1935. apple breeding: inheritance of tree shape in apple progenies.
Amer. Soc. Hort. Sci. Proc. (1934) 32: 256-260.
(13) Macoun, W. T.
1929. progress in apple breeding in Canada. Amer. Soc. Hort. Sci.
Proc. (1928) 25: 117-122.
(14) Nebel, B. R.
1931. RECENT FINDINGS IN CYTOLOGY OF FRUITS (CYTOLOGY OF PYRUS III).
Amer. Soc. Hort. Sci. Proc. (1930) 27: 406-410, Illus.
(15) Taylor, W. A.
1898. THE FRUIT INDUSTRY, AND SUBSTITUTION OF DOMESTIC FOR FOREIGN-
GROWN fruits. II. S. Dept. Agr. Yearbook, 1897: 305-344, illus.
(16) Vincent, C. C, and Longley, L. E.
1930. apple breeding in idaho. Idaho Agr. Expt. Sta. Research Bull.
8, 58 pp., illus.
(17) Wellington, R.
1924. an experiment in breeding apples, ii. N. Y. State Agr. Expt.
Sta. Tech. Bull. 100, 149 pp.
APPENDIX
The following summary includes the more important fruit-breeding stations in
Europe.
Czechoslovakia
Pr&honice; State Institute for Horticultural Research (director, Ing. Fr. Lan-
dovsky; chief, Division of Fruit Trees and Nurseries, Ing. J. Soucek). — Objective:
To secure fruits of better quality' with good storage and utilization properties.
Lednice, Morava; Furst Liechtenstein Plant-Breeding Institute (director, Prof.
Dr. Fr. Frimmel). — Extensive breeding investigations of apples and peaches are
being conducted. Crosses of several apple varieties are at fruiting age and are
being tested in comparison with standard varieties.
England
Long Ashton: Agricultural and Horticultural Research Station, University of
Bristol (director, Prof. B. T. P. Barker). — In connection with general fruit investi-
gations, the station conducts breeding investigations on apples, pears, plums, and
berries. Several apple varieties, one pear, and four plums have been named
and distributed. The objective in the breeding work is to produce high-quality
dessert varieties.
East Mailing, Kent; Horticultural Research Station (director, R. G. Hatton). —
Breeding investigations include the following principal lines:
(1) Apples. — Production of rootstocks immune to woolly aphis and conferring
disease resistance on the scions; production of fruiting varieties resistant to
woolly aphis; production of commercial varieties ripening at times when present
English varieties are not available.
APPLES 603
(2) Plums. — Production of new varieties of rootstock that propagate readily
and confer resistance to silver leaf and to bacterial dieback diseases.
(3) Pears. — Production of improved varieties of quince stock compatible with
pear varieties, and production of commercial pear varieties of high quality.
Merlon; John Innes Horticultural Institution (director, Sir Daniel Hall). — The
institution is engaged primarily in genetic and cytological research from the
standpoint of pure science. When the investigations on inheritance in fruit
produce varieties of promise for commercial cultivation, they are selected and
given an extended try-out. ' ■■
(1) Apples. — Four thousand seedlings and varieties provide data for the study
of the inheritance of characters. About 40 are under extended tests as market
varieties. Breeding of rootstocks resistant to woolly aphis, carried on in collabor-
ation with the East Mailing station, has yielded seedlings of promise now
under trial.
(2) Plums. — A large number of seedling plums are being grown in the study of
inheritance of characters, particularly of self-incompatibility. Selected seedlings
arc under trial for commercial value.
(3) Cherries. — A large number of varieties of sweet cherry have been raised in
the study of cross incompatibility, some of which are now under commercial trial.
Germany
Berlin; Institut fur gartnerischen Pflanzenbau, Friedrich-Wilhelms-Universitat
(director, Prof. Erich Maurcr) .—Breeding of tree fruits consists of the selection
of vegctatively propagated rootstocks for apples, pears, sweet cherries, and
plums. Around 3,000 clons are under observation.
Berlin; Institut fiir Obstbau, Friedrich-Wilhelms-Universitat (director, Prof.
Erwin Kemmer). — Investigations on the value of seedlings of varieties and from
the wild stocks for stone fruits and pomes.
Oeisenheim a.Rh.; Versuchs-und Forschungsanstalt fiir Wein-, Obst-, und Garten-
bau (director, Prof. Dr. Rudloff). — Breeding of tree fruits has been conducted
since 1884. A series of new apple and pear varieties has been developed through
growing open-pollinated seedlings of named varieties or through hybridization
of named varieties. Twelve varieties of pear and seven varieties of apple have
been named.
Muncheberg (Mark); Kaiser Wilhelm-Institut fur Ziichtungsforschung (director,
Prof. Dr. Rudorf) . — An intensive program of investigation, particularly to develop
disease-resistant varieties of fruits. In the apple work, the important objectives
are to secure greater resistance to apple scab and to cold and frost, and to develop
high-quality market and table varieties. In the work on scab resistance, mass
infection of the seedlings of crosses between cultivated varieties and scab-resistant
apples is practiced. Over 16,000 apple seedlings are under observation in this
work.
(1) Pears. — The important objectives are to develop pears resistant to pear
scab and to develop high-quality, large-sized summer pears. The testing of
resistance to scab is similar to that of apples. Four thousand pear seedlings are
under observation.
(2) Cherries. — One objective is to secure cherries resistant to brown rot. A
largo number of crosses of sweet X sour varieties have been tested. Tests of the
cross- and self-sterility of the Fi hybrids of sour X sweet cherries are also being
made.
(3) Plums. — Testing of strong-growing seedlings of Prunus cerasifera from
western Asia for their resistance to unfavorable climatic conditions, their adapta-
tion, vigor, productiveness, and fruit quality. These are being crossed with other
types of plums. Observations are made of a large number of seedlings of crosses
between Mirabelle and Reinc Claude types.
(4) Apricots. — Seedlings of the vigorous wild apricot of Asia are being tested
for their resistance to climatic conditions, adaptation, vigor, productiveness, and
fruiting value, and are being crossed with cultivated varieties.
(5) Peaches. — A large quantity of seedling material of varieties and crosses
between varieties is being tested for the resistance of the buds against late frosts
and winter temperatures and the resistance of the trees against peach leaf curl.
Zweigstelle, Naumburg (Saale); Biologische Reichsanstalt fiir Land- und Forst-
wirtschaft (director, Dr. Bonier). — The objectives are the development of high-
quality apple varieties and of stocks that are highly resistant to woolly aphis,
604
YEARBOOK, 1937
mildew, and scab. A large number of Fi hybrids between resistant wild types
and cultivated varieties are under observation.
Pillnitz a. d. Elbe; Slaatliche Versuchs- und Forschungsanstalt fur Garlenbau
(director, Prof. Schindler). — Investigations on understocks for apples, pears,
quinces, plums, cherries, and peaches. The objectives are to obtain good con-
geniality between stock and scion and to obtain cold resistance and good propaga-
tion qualities for the production of clon stocks.
Sweden
Alnarp; Lantbruks-, Mejeri-och Tradgdrdsinstitut (director, L. Forsberg). —
Investigations are conducted with apples, pears, plums, and cherries. Specially
hardy apple varieties producing large yields are crossed with those of fine quality
but not hardy in central and northern Sweden. A total of 3,750 seedlings, repre-
senting 136 combinations, are being grown. Crosses between triploid and diploid
strains have yielded some trees that show promise. Crosses have been made
between pear varieties for quality and productiveness, involving 41 combinations
and 570 individual trees.
In plum and cherry breeding, difficulty has been experienced in obtaining satis-
factory germination. Only one promising type of plum has been secured to date.
A small number of crosses between soft-fleshed, high-yielding, early-bearing
cherry varieties and the hard-fleshed, sweet varieties have been made.
Union of Soviet Socialist Republics
During the past decade plant explorers from the Soviet Union gathered at
central breeding stations in that country much of the available material of the
world that may be of promise for production there or for breeding purposes.
Under the direction of the Institute of Plant Industry, 14 plant-breeding centers
have been set up in different parts of the Union. At these centers, fruit breeding
to develop varieties adapted to the different parts of the Union constitutes a
major line of investigation. Genetic and cytological studies are being made.
Table 1. — Origin of important apple varieties
Variety
Where originated
How originated
When originated
Arkansas (Mammoth
Black Twig) .
Arkansas Black
Baldwin _._
Ben Davis
Black Ben
rionum
Collins.-
Cortland
Beliciotis
Esopus Spitzenburg..
Fameuse
Gano
Golden Delicious
Gravenstcin
Grimes Golden
Haralson.
Hubbardston
Ingram
Jonathan
King David
I.imbertwig
Mcintosh...
Maiden Blush
Missouri Pippin ,
Northern Spy
Eheas Mill. Ark.
Benton County, Ark.
Lowell, Mass
Tenaessee, Kentucky, or
Virginia.
Washington County, Ark...
Davidson County, N. C
Fayetteville, Ark
New York Agricultural Ex-
periment Station, Geneva.
Peru, Iowa
Esopus, N. Y
France or Canada
Kentucky or Missouri
Porter, W. Va
Europe, probably Germany-
West Virginia
Minnesota Fruit Breeding
Station, St. Paul.
Hubbardston, Mass..
Springfield, Mo
Ulster County, N. Y.
Washington County, Ark...
Knox County, Ohio (?)
Dundas District, Ontario,
Canada.
First known at Burlington,
N.J.
Kingsville, Mo
East Bloomfield, N. Y
Chance seedling.
.do.
.do.
Chance seedling
do
Ben Davis X Mcintosh.
Chance seedling..
Chance seedling.
Chance seedling
Seedling of Malinda..
Chance seedling
Seedling of Balls
Believed seedling of
Esopus.
Chance seedling
Seedling
Chance seedling..
Chance seedling.,
do "...
1833.
About 1870.
About 1740; widely in-
troduced, 1784.
Shortly after 1800.
About 1880.
Cataloged 1860.
About 180.5.
Introduced 1912.
Tree grew about 1880.
Probably before 1800.
Distributed by earliest
French missionaries
before 1700.
About 1875.
Introduced 1910.
Introduced to United
States prior to 1820.
Known in 1804.
Introduced 1922.
Known in 1832.
Between 1844 and 1855.
Described in 1820.
Introduced 1901.
Soon after 1812.
Propagated about 1870.
Popular before 1817.
Seed planted about 1840.
Planted about 1800.
APPLES 605
Table 1. — Origin of important apple varieties — Continued
Variety
Whore originated
How originated
When originated
Northwestern Green-
ing.
Oldenburg (Dachas).
Ortlcy
Paragon
Payne
Red Astrachan
Red June
Rhode Island Green-
ing.
Rome Beauty
Roxbury-
Smokehouse
Stark _.
Starr
Stayman Winesap
Summer Rambo
Tolman Sweet
Tompkins King
(King).
Twenty Ounce
Wagener
Wealthy
White Pearmain
Williams
Willowtwig
Winesap.-
Winter Banana _
Wolf River
Yellow Bellflower
Yellow Newtown
Yellow Transparent -
York Imperial..
Waupaca County, Wis..
Russia
Chance seedling..
New Jersey
Fayetteville, Tenn.
Everton, Mo _
Chance seedling..
_...do
.do.
Sweden
North Carolina.
Probably near Newport,
R.I.
Lawrence County, Ohio
Probably Roxbury, Mass..
Lancaster County, Pa
Probably Ohio
Woodbury, N. J
Leavenworth, Kans
Europe, probably France. .
Probably Dorchester, Mass..
Probably near Washington,
N.J.
Unknown; possibly Con-
necticut.
PennYan, N. Y _
Produced by Peter Gideon,
Excelsior, Minn.
Unknown; first grown in
Indiana.
Roxbury, Mass
Unknown; first grown in
Ohio.
Unknown; grown very early
in New Jersey.
Adamsboro, Ind
Wolf River, Wis
Crosswieks, N. J
Newtown, N. Y
Chance seedling..
..._do
do.
do.
.do.
.do.
_<lo.
Seedling of Winesap..
Unknown
Chance seedling..
____do_._
_do.
Seedling
Seedling of Cherry crab.
Unknown
Chance seedling..
Unknown I..
.do.
Seedling..
do...
do...
Russia.
York, Pa.
....do....
Unknown.
Seedling..-
Introduced 1872.
Imported to United
States via England
about 1835.
Described in 1817.
From seed planted about
1830.
From seed planted about
1840.
Imported into United
States In 1835.
Described as early as
1848.
Probably about 1700.
Introduced 1848.
Prior to 1049.
Beforo 1800.
Described 1867.
Propagated in 1805.
First fruited in 1875.
Known in United States
since 1817.
Described in 1822.
Before 1804.
Described in 1844.
Seed planted in 1791.
Described in 1809.
Cataloged in 1858.
About 1750 or before.
Described in 1848.
Described 1817; known
long before.
About 187ii.
Introduced 1881.
Described in 1817.
Well known as an old
tree by 1759.
Imported by U. S. De-
partment of Agricul-
ture, 1870.
Propagated about 1830;
described 1853.
Table 2.
-Apple varieties developed in breeding work at agricultural experiment stations
in the United States
Place of origin and
variety
Parentage '
Date
crossed
or seed
col-
lected
Date
intro-
duced
1921
1921
1921
1921
1921
1914
1921
Characteristics
Iowa Agricultural Ex-
periment Station,
Ames:
Adel
1902
1908
1908
1908
1906
1887
1900
Afton
Wolf River X Harrington.
Allen Choice X Perry
Russet.
Colorado Orange X Allen
Choice.
Salome X Jonathan
(?)
Red; midwinter.
Red; late keeper.
Yellow Newtown type; hardy, late
keeper.
Jonathan type; later keeper; free of
Jonathan spot.
Hawkeye Greening-
fruit.
I Parents marked with (?) are somewhat uncertain.
606
YEARBOOK, 1937
Taiile 2. — Apple varieties developed in breeding work at agricultural experiment stations
in the United States — Continued
Place of origin arid
variety
Iowa Agricultural Ex-
periment Station,
Ames— Continued.
Joan _.
Macy
Maud
Monona..
Secor....
Sharon.
Minnesota Agricultur-
al Experiment Sta-
tion, St. Paul:
Minnehaha .-.
Folwell
Wedge
Haralson..
Beacon
Missouri State Fruit
Experiment Station,
Mountain Grove:
Faurot
Conard.
Parentage
Anisim X Jonathan
Northwestern Greening X
Wealthy.
Mcintosh X Longfleld
Wolf River X Harrington.
Salome X Jonathan
Mcintosh X Longfield..
Malinda, open-pollinated..
Opeu-pollinalcd seedling
of Malinda seedling.
Bon Davis, open-pollinated.
Malinda, open-pollinated..
...do
lieu Davis X Jonathan-
do
Wrlght-
Fpan.
.do-
Orovc Ingram x Delicious.
Whetstone.
Conard X Delicious..
Missouri Agricultural
Experiment Station,
Columbia:
Whitten
N'ow York Agricultural
Experiment Station,
Geneva:
Carlton
Cortland-
Early Mcintosh....
Ingram X Delicious.
Montgomery X II e d
Astrachan.
Ben Davis X Mcintosh .
Yellow Transparent X
Mcintosh.
Date
(Tossed
or seed
col-
lected
Date
intro-
duced
1906
1932
1908
1921
1906
1908
1922
1921
1906
1906
1921
1921
1907
1906
1920
1922
1908
1922
1907
1923
1907
1936
1901
1935
1901
1935
1001
1935
1901
1935
1915
1935
1915
1935
1905
1925
1011
1923
1898
1915
1909
1923
Characteristics
Large, full red, very productive;
November to February.
Wealthy type, larger; September.
Red; August-September.
Red, large, perfumed flavor; Novem-
ber-December.
Late keeper, best quality.
Hardy, very good quality; Novem-
ber-March.
nardy, productive.
Hardy; fruit of good size and quality.
Vigorous, hardy tree; fruit good size
and color; good baking apple.
Tree very hardy, productive; fruit
attractive; good storage quality.
Very hardy; fruit early, attractive.
Tree resistant to disease; fruit me-
dium size, high color, good storage
and dessert quality.
Tree vigorous, disease-resistant; fruit
large, colors well; good quality,
tart; matures 1 week after Jona-
than.
Fruit larger than Jonathan, attrac-
tive, colors well; dessert and stor-
age quality good; tree vigorous,
productive, very resistant to dis-
ease: fruit ripens with Jonathan.
Tree spreading, vigorous grower,
regular producer; fruit large, well
colored, attractive; excellent stor-
age quality; fruit ripens 2 weeks
after Jonathan.
Tree fairly vigorous, spreading, late
blossoming, resistant to scab,
blotch, and blight; fruit attractive,
good size, good quality, colors well;
ripening season later than Winesap;
excellent keeper.
Tree vigorous, good producer; fruit
smooth, largo, colors well, uniform
in size and shape; excellent storage
quality, fair dessert quality.
Tree vigorous, prolific; fruit above
medium size; yellow with red blush;
quality good.
Tree vigorous; fruit large, attractive,
dark red; flesh white, tender, juicy,
sprightly; ripens about with
Wealthy.
Tree large, vigorous, spreading,
hardy, productive; fruit slightly
oblate, large, well colored, quality
good; ripens almost with Mcin-
tosh but has better storage quality.
Tree vigorous, iiardy, productive;
fruit red, oblate, attractive; flavor
good; season 10 days after Yellow
Transparent.
APPLES
607
Table 2. — Apple varieties developed in breeding ivork at agricultural experiment stations
in the United States — Continued
Place of origin and
variety
New York Agricultural
Experiment Station,
Geneva — Oontd.
Kendall
Parentage
Lodi.
Macoun.
Medina..
Milton...
Newfane.
Ogden
Zusoff X Mcintosh .
Montgomery X Yellow
Transparent.
Mcintosh X Jersey Black.
Deacon Jones X Delicious-
Yellow Transparent X
Mclntosli.
Deacon Jones X Delicious.
Zusoff X Mcintosh
Orleans
Red Sauce-
Sweet Delicious. .
Sweet Mclntosli.
Deacon Jones X Delicious
Deacon Jones X Wealthy..
Deacon Jones X Delicious
Lawver X Mcintosh
Tioga I Sutton X Northern Spy...
Ohio Agricultural Ex-
periment Station
Wooster:
Franklin ___
Downing
Kirtland _.
Warder
Shaw
South Dakota Agri-
cultural Experiment
Station, Brookings:
Hibkee
Sereda.
Mcintosh X Delicious..
Gallia X Kirtland.
Ingram, open-pollinated..
Romc, open-pollinated...
Rails X Mother
Graft hybrid of Hibernal
and Milwaukee.
Harry Kaump X (Olden-
burg?).
Date
crossed
or seed
col-
lected
1000
1011
1000
1911
1912
1911
1010
1911
1009
1899
1925
1029
191.5
191.5
Date
intro-
duced
1923
1923
1923
1928
1028
1924
192(i
1923
1923
1915
1037
1937
1937
1910
191(3
Characteristics
Tree moderately vigorous, appar-
ently hardy; fruit large, well colored
dark red; quality very good; sea-
son with Mcintosh; possibly bet-
ter storage quality.
Tree of Yellow Transparent type,
vigorous; fruit similar to
Yellow Transparent but larger;
ripens later.
Tree upright, moderately vigorous;
fruit medium size, oblate, dark
red, quality very good; season 1
month after Mcintosh.
Fruit of Delicious type and general
quality but more highly colored;
slightly later in season.
Tree hardy, vigorous; fruit pinkish-
red, attractive, crisp, sometimes
irregular in shape; quality good;
season with Wealthy.
Fruit of general Delicious type; qual-
ity good; in season with Delicious.
Tree hardy, productive; fruit large,
oblate, dark red; quality good;
ripens just before Mcintosh.
Delicious type; in season with Deli-
cious; keeps longer in common
storage.
Large, roundish-conic apple, red,
with red flesh to core lines; ripens
medium to late.
Fruits flatter than Delicious; large,
sweet, aromatic.
Resembles Mcintosh in appearance,
flavor, and aroma; primarily
adapted for home use.
Tree large and vigorous, hardy,
healthy; fruit large, round-oblate,
late, yellow, tart; excellent culinary
fruit.
Fruit medium-sized; quality very
good; yellow undercolor with
bright, attractive red; season with
Jonathan.
Fruit above medium to large; very
highly colored; quality good; bloom-
ing season late; storage to mid-
winter.
Fruit large, roundish oblr.te to oblong,
attractive, well-colored; quality
good; holds in storage till late
winter; late blooming.
Fruit medium-sized, roundish ob-
late, attractive .and well colored;
storage to end of January; late
blooming.
Fruit above medium size, roundish
oblong; quality good to very good;
storage to late winter; late bloom-
ing.
Flesh and core Milwaukee type,
surface coloring of Hibernal.
Resembles Yellow Transparent in
quality and season; yellow; juicy;
sprightly.
608
YEARBOOK, 1937
Table 2. — Apple varieties developed in breeding work at agricultural experiment stations
in the United States — Continued
Place of origin and
variety
Parentage
Date
crossed
or seed
col-
lected
Date
intro-
duced
Characteristics
South Dakota Agri-
cultural Experiment
Station, Brookings —
Continued.
1019
1919
1919
1919'
1920
1922
1922
1922
1927
1927
1928
1932
1933
1933
1934
do
stripes. Fameuse type; sweet;
winter apple of high quality.
Complete hardiness for far north
questionable.
Fruit medium size, oblate, regular,
Hibernal X Gravenstein...
Baldwin X Wild Crab
from Minnesota.
red striped; flesh white; pleasant,
subacid; season midwinter.
Fruit medium size, yellow, oblate;
sweet, excellent quality; subject to
blight.
Fruit small, oblate, dark red; sub-
acid; season throughout winter;
hardy.
Mcintosh X (Virginia
Crab?).
Grimes Golden X (Olden-
burg?).
Roxbury X (Oldenburg?).
Bismarck X Mercer,. .. _
Wealthy X (Hibernal?) . ._
flesh white; subacid; season fall;
tree very hardy, productive.
Goldo..
stripes; quality good; season late.
Oxbo
appearance; quality good; tree
hardy, vigorous.
season late fall.
Elta_ _
striped with brown-red; flesh yel-
low; pleasant, subacid to sweet;
early bearer; season probably
winter.
conical; rich orange-yellow, red
striped; quality good, sweet;
season late fall.
Tolmo
Tolraan Sweet X Olden-
burg?) .
striped with red; flesh white; sub-
acid, spicy, fragrant; late winter.
Volga
Oldenburg; flesh white; pleasant,
subacid; quality good; season fall.
cal, bright red; flesh red. fine; juicy,
subacid; season late fall.
Seedling of Auisim
culinary fruit.
flesh white; juicy, subacid; flesh
red next to skin; fruit rather small.
Table 3. — Apple crosses of which five trees or more have fruited, and number of promising
seedlings resulting, in breeding work at State experiment stations in the United States
Cross
Locality
Total
fruited
Selec-
tions re-
tained
Geneva
_-.. do.
X
V
Number
7
11
"""'i "
48
30
59
12
48
.... i 8
Xttmber
0
0
Iowa
do.
0
2
. .. do
2
do
0
do
1
.. do.
n
do
3
Anisim X Salome _
do.
0
APPLES
609
Tadle 3. — Apple crosses of which five trees or more have fruited, and numl>er of promis-
ing seedlings resulting, in breeding work at State experiment stations
in the United States — Continued
Cross
Baldwin X Yellow Transparent
Barry X Delicious
Ben Davis, selfed
Ben Davis X Alien Choice
Ben Davis X Black Annette
Ben Davis X Delicious
Ben Davis X Esopus Spitzenburg
Ben Davis X Jonathan
Do.
Do
Ben Davis X Longfiold
Ben Davis X Mcintosh
Ben Davis X Mother
Ben Davis X Rome Beauty
Ben Davis X Scott Winter.. _ ■
Ben Davis X Wagoner
Ben Davis X Yellow Newtown—
Do
Black Annetto X Salome
Black Annette X Utter
Black Ben X Jonathan
Black Ben X King David :
Black Ben X Mcintosh
Black Ben X Oldenburg
Black Gilliflower X Delicioa«
Bloomfleld X Delicious
Bioomfleld X Oldenburg
Boiken X Charlamoff
Boiken X Gravenstein
Boiken X Grimes Golden
Boiken X Macoun
Boiken X Mcintosh
Boiken, open-pollinated
Boiken X Wealthy
Briar X Mercer
Brilliant X Black Annetto
Brilliant X Malinda
Canada Baldwin X Black Annette
Canada Baldwin X Patten
Canada Baldwin X Winesap
Charlamolt X Black Ben - --
Charlamoff X Delicious
Charlamoff X Jonathan --- ■■-
Charlamofl X Stayman Winesap
Chenango X Lodi
Colorado Orange X Allen Choice ---
Colorado Orange, open-pollinated
Colorado Orange X Jonathan
Colorado Orange X Oldenburg
Cortland X Crimson Beauty
Cortland X Kendall
Cortland X Mcintosh
Cortland X Eed Spy
Cortland X Yellow Newtown
Cox Orange X Golden Delicious
Cox Orange X Magnet
Cox Orange X Sta. 3056 (Lymans Red Fleshed, open-po)
linated).
Cox Orange X Medina
Cox Orange X Newfane
Dam X Ingram
Deacon Jonos X Chenango
Deacon Jones X Delicious
Deacon Jones X King David
Deacon Jones X Miller Seedless
Deacon Jones X Northern Spy
Deacon Jones X Red Spy__
Deacon Jones X Sta. 1297 (Deacon Jones X Vi ealthy)
Deacon Jones X Red Sauce
Deacon Jones X Wealthy
Deacon Jones X Yellow Newtown
Delicious, selfed
Do - -
Locality
Total
fruited
Geneva, N. Y
Iowa
....do
—.do
....do
....do
Idaho
....do —
Mountain Grove, Mo.
Geneva, N. Y —
Iowa
Geneva, N. Y .
....do
Idaho
Iowa
Idaho..
do... —
Geneva, N. V:
Iowa
do
do
Minnesota
Iowa
Minnesota
Geneva, N. Y
Maryland
do
Minnesota
Geneva, N. Y
do
Iowa
do
Minnesota
do
Iowa —
do
do
do
do
do
Minnesota
....do --
....do
....do
Geneva, N. Y
Iowa
Minnesota...
Iowa
Minnesota
Geneva, N. Y
.....do
....do
do
do
do
do
do
....do
....do
Missouri... ...
Geneva, N. Y_
....do
__..do -
....do -
do -
....do
do
do
do.. -
do
Ohio
Minnesota
Ni
Selec-
tions re-
tained
umber
6
13
5
0
41
44
498
3. 700
915
12
20
11
21
390
f>
1,053
57
12
5
35
5
0
0
48
f>
19
12
52
11
24
7
13
SB
71
0
5
31
.5
0
22
33
109
9
10
8
25
5(5
no
20
22
13
20
12
Number
0
0
0
0
o
0
610
YEARBOOK, 1937
Table 3. — Apple crosses of which Jive trees or more have fruited, and number of promis-
ing seedlings resulting, in breeding work at State experiment stations
in the United Stales — Continued
Cross
Locality
Total
fruited
A'untber
9
7
28
92
U
30
74
7
72
71
36
23
10
6
0
25
12
11
9
5
7
5
25
10
17
34
35
74
365
279
7
24
9
9
16
Selec-
tions re-
tained
Xamber
Delicious X Babbitt- . . .. .... _ _.
Delicious X Daru _ . __ _ _ . .
Ohio
0
4
Delicious X Deacon Jones _
2
Ohio
Delicious X Hibernal
4
Delicious X Jonathan. - _
Delicious X Okabena . . . .
Iowa. . ... _. _
Minnesota.
1
Delicious X Oldenburg ... . .. .. .. ...
Delavan X Clemons No. 1- . . .-
do
11
0
Dinwiddie X Northern Spy.
Ohio
I
Dolgo (crab) X Delicious . . ....
North Dakota
1
Dudley X Scott Winter.
0
Early Harvest X Williams... . .. ..
Maryland _ .
0
Early Mcintosh X Cox Orange
Geneva, N. Y
1
Early Mcintosh X Deacon Jones.. . .
do....
0
Early Mcintosh X Vrimate
do...
Early Mcintosh X Red Spy
do -
0
1
Early Mcintosh X Sta. 845 (Red Canada X Yellow
do
Transparent).
Early Mcintosh X Sla. 2391 (Montgomery X Red As-
trachan).
Early Mcintosh X Sta. 2575 (Montgomery X Yellow
do
....do
0
0
Transparent) .
Early Ripe X Early Ilarvest ..
0
Early Ripe X Red Astrachan. ... ..... .
Early Ripe X Williams.. ... _ ._
Early Ripe X Yellow Transparent . .
Esopus Spitzenburg X Ben Davis ....
Esopus Spitzenburg X Yellow Newtown . .
Esopus Spitzenburg X Rome Beautv ... _ __ _
Esopus Spitzenburg X Wegener .... ..
do
do
do
Geneva, N. Y . ... . .
Idaho.. ._ _. _
do
do
Ohio
0
0
0
1
0
5
1
Gano X Baltimore
do....
do...
do
Grimes Golden X Akin...
22
94
9
34
459
9
35
35
100
16
6
6
38
5
35
20
50
107
Unknown
Unknown
9
19
Unknown
Unknown
37
21
71
21
52
29
25
JJ9
745
Grimes Golden X Boiken... _. . .. .
Geneva, N. Y
Ohio
Minnesota
Grimes Golden X Louise ... __
Grimes Golden X Okabena
0
Grimes Golden X Oldenburg _ .
do
l'J
Grimes Golden X Red June . . . . ...
Ohio
Grimes Golden X Stayman Winesap . _ ..
Maryland __
0
Grimes Golden X Wealthy . .
Grimes Golden X White Pippin... ...
Minnesota
Ohio _
1
Grimes Golden X Sta. 7045
Minnesota
0
liarrington X Delavan ........ ..
do- .
Harrington X Ralls No. IS ... ... ...
Helen, open-pollinated ..... ....
.. .-do
Geneva, N. Y. .. .. ..
3
Hibernal X Delicious . _ .
Do
Minnesota
HyslopXLady
0
3
Ingram, selfed _
Ingram X Delicious.. ._
Mountain Grove, Mo
do....
Ingram X Jonathan
Ingram X Lily of Kent
do. _
do
5
Ingram X Rome Beauty . ...
Maryland
0
1
Ingram X Salome. . _______....
Ingram X Twenty Ounce . .
Mountain Grove, Mo . .
do
Ingram X Wolf River. . .. ..
Ingram X York Imperial-
do.—
1
0
0
Iowa X Mcintosh
Jersey Black X Canada Baldwin..
do
Jersey Black X Jonathan _
do
Jersey Black x Louise. .
do..-
0
i
0
17
3
Jersey Black x Mcintosh.. ... ... .. .
do
Jonathan X Anisim . _ _ _. __
do. .
Jonathan X Delicious ..
Jonathan X Esopus Spitzenburg _
Idaho
APPLES
611
Table 3. — Apple crosses of which five trees or more have fruited, and number of promis-
ing seedlings resulting, in breeding work at State experiment stations
in the United States — Continued
Cross
Locality
Total
fruited
Selec-
tions re-
tained
Number
7
85
9
48
477
151
193
15
270
21
641
41
120
9
6
59
8
17
279
5
56
81
32
178
48
20
15.
5
7
6
4,000
141
132
10
30
5
21
27
6
9
56
0
10
24
24
30
36
107
30
37
15
13
6
35
39
9
52
80
17
10
5
0
5
48
141
144
8
38
Unknown
5
7
15
12
45
Number
0
do.
58
do
10
0
Do
1
0
Jonathan X Wealthy .. . . ... . .
1
0
5
do
0
0
King David X Delicious _. . . ___.._
Do ._-
Mountain Grove, Mo
0
7
King David X Grimes Golden .. ...
King David X Okabena.. . . . . _.
do
do
1
0
King David X Oldenburg- . .
Kjnne No. 12, selfed.. . . ._ . _
do
31
0
Kinne No. 12 X demons
Lady X "Wealthy 1
do.
0
1
do.
2
0
do
do
0
do
Ohio
Minnesota
0
Minnesota
Geneva, N. Y. ...
do
8
fl
do
do
0
do
0
do
do
o
do
do
o
Mcintosh X Golden Delicious .. J... _.
do
do
0
do
0
. .do
do
1
10
Geneva, K. Y
do
1
o
do....
0
Mcintosh X Red Spy
do
o
.do....
0
Mcintosh X Sta. 1297 (Deacon Jones X Wealthy)..
do
0
do
0
Mcintosh X Sta. 1943 (Deacon Jones X Delicious)
Mcintosh X Wealthy.
do
...do
0
0
.do
Mcintosh X Zusoff Winter—
do
0
do
0
do
0
Miller Seedless X Koine Beauty..
do
0
do
0
fl
5
do
0
()
do
0
Mountain Grove, Mo
Ohio
1
Mother X Ralls _
0
0
do....
0
do
0
Northern Spy X Cortland
Genova, N, Y
0
612
YEARBOOK, 1937
Table 3. — Apple crosses of which five trees or more have fruited, and number of promis-
ing seedlings resulting, in breeding work at State experiment stations
in the United States — Continued
Cross
Northern Spy X Delicious
Northern Spy X Ingram
Northern Spy X Miller Seedless
Northern Spy X Patten
Northern Spy X Balls
Northern Spy X Borne Beauty
Northorn Spy X Wealthy
Northern Spy X Yellow Newtown
Northwestern Greening X Harrington.
Northwestern Greening X Wealthy
Do-
Okabena X Delicious..-
Okabena X Grimes Golden
Okabena X Oldenburg
Oldenburg, selfed- _
Oldenburg X Black Ben
Oldenburg X Colorado Orange
Oldenburg X Delicious
Oldenburg X Gilbert Winesap —
01 denburg X Grimes Golden
Oldenburg X Iowa
Oldenburg X. Jonathan _ .. .
Oldenburg X King David...
Oldenburg X Mcintosh..
Oldenburg X S tayman Winesap
Oldenburg X Sta. 7045
Oldenburg X Yellow Transparent
Opalescent X Borne Beauty
Orenco X Cortland --
Orenco X Mcintosh
Otsego X Miller Seedless
Patten X Colorado Orange
Patten X Delicious
Patten X Jonathan
Patten X Winesap
Patten- X Wolf Biver
Patten X Sta. 7045
"Patten No. 20" X Jonathan
"Patten Ns. 20", selfed
"Patten No. 20", open-pollinated
Pear-shaped Apple, open-pollinated—.
Perkins, open-pollinated
Balls X Alexander
Ralls X Delicious
Balls X Jonathan
Do
Balls X McAfee
Balls X Mother
Ralls X Northern Spy
Do
Balls X Eomanite —
Ralls X Boman Stem...
Balls X Borne Beauty
Do - -
Ralls X Staymau Winesap
Balls X Wolf River-.
Bainbo X Northern Spy
Bed Astrachan, open-pollinated
Red Canada X Boiken
Bed Canada X Delicious
Do
Bed Canada X Dunwiddie
Bed Canada X Yellow Transparent...
Bed June X Early Ripe
Bed June X Yellow Transparent
Red Spy X Cortland
Red Spy X Cox Orange
Red Spy X Delicious
liepka Malenka X Black Annette
Rhode Island Greening X Cortland....
Roman Stem, selfed
Roman Stem X Grimes Golden
Roman Stem X Jonathan
Roman Stem X Wealthy
locality
Geneva, N. Y
Ohio
Geneva, N. Y
Iowa
Ohio
do.
Geneva, N. Y _ .
do
Iowa
do
Minnesota
do
do
....do
Iowa
Minnesota
do-
do
do—
do
Iowa
Minnesota .
do
Geneva, N. Y
Minnesota
do
Geneva, N. Y
do-
.....do— -
. _..do
. —do
Minnesota
do
do
do
do
do
Iowa__
do
North Dakota
Geneva, N. Y
Minnesota
Columbia, Mo
do
do
Mountain Grove, Mo_.
do
Ohio
do
Geneva, N. Y
Iowa
do
Ohio
Geneva, N. Y •
Columbia, Mo
do
Ohio
Maryland
Ohio
do
Geneva, N. Y .
Ohio
Geneva, N. Y
Maryland—
do
Geneva, N. Y
do
do
Iowa
Geneva, N. Y
Iowa
do
do.
do...
Total
fruited
Number
7
27
49
7
34
2,'i
8
65
13
It
23
50
(18
73
12
42
17
376
30
110
15
64
129
L
14
61
12
17
12
30
69
39
43
81
7
144
74
11
9
500
7
127
7
8
14
Unknown
Unknown
52
30
9
.522
15
6
8
41
11
26
12
7
159
17
70
9
10
5
47
40
104
5
7
35
101
Selec-
tions re-
tained
Yumber
0
1
0
2
1
1
0
0
0
5
1
1
APPLES
613
Table 3. — Apple crosses of which five trees or more have fruited, and number of promis-
ing seedlings resulting, in breeding tvork at State experiment stations
in the United Stales — Continued
Cross
Locality
Total
fruited
Selec-
tions re-
tained
Rome Beauty x Esopus Spltzonburg .
Geneva, N. Y... _
do ._ _
do...
Number
10
10
20
70
0
9
31
38
843
5
32
9
43
43
17
13
5
14
7
11
144
51
1,144
40
397
33
10
104
9
5
17
5
21
21
88
17
18
109
43
21
14
9
10
23
12
B
5
10
Number
Rome Beauty X Jersey Black ,.
0
. do
Rome Beauty X Northern Spy _
Ohio
Do
Rome Beauty X Oldenburg . .. ....
2
Rome Beauty X Opalescent ..... ... .
1
Rome Beauty x Yellow Newtown . ..
Rome Beauty X Wealthy. . .. __ _.
Ohio-
San Jacinto X Starr._
Geneva, N. Y. ...
do
0
San Jacinto X Williams _
San Jacinto X Yellow Transparent .....
Scott Winter X Salome _
do
0
- do
Stayman Winesap X Black Ben .
Stayman Winesap X Grimes Golden. _ _ _ ... .
do
0
0
Tolman Sweet X Ben l>avis .
Wagener X Grimes Golden. _
o
Wagener X Mcintosh . ...
do
o
do
7
Washington Black Beauty, open-pollinalcd
Minnesota __ .
Ohio
4
Wealthy, selfed _
(i
Wealthy X Allen Choice.
0
do
. .do
.. do
Wealthy X Colorado Orange ....
.. do .
1
0
Wealthy X Jonathan ..
Wealthy X Lady __
Wealthy X Okabena
do
Minnesota..
_...ido_
2
1
10
Wealthy X Oldenburg
do
o
1
Wealthy X Wolf River
Wealthy X Sta.7045
Minnesota
- do .
3
1
1
White Pippin X Grimes Golden ... ... . ...
Ohio.
Williams X Yellow Transparent,
0
Ohio
0
0
do..
do ..
do. .
3
Maryland .
Table 4. — Locations and personnel of apple-breeding ivork in the United States
State, institution, and location
Date
begun
Previous workers
Present staff
Idaho:
Agricultural Experiment Station, Mos-
cow.
Illinois:
Agricultural Experiment Station, Ur-
bana.
Iowa:
Agricultural Experiment Station, Ames.
Maine:
1909
1908
1880
1911
1900
C. C. Vincent, 1909-33
C. S. Crandal], 1908-29
J. L. Budd, 1880-1905; S. A.
Beach, 1905-22.
Lief Verner.
J. C. Blair, M. J. Dor-
sey, J. S. Whitmire.
H. L. Lantz, T. J.
Maney, B. S. Pic-
kett.
R. M. Bailey.
Maryland:
Agricultural Experiment Station, Col-
lege Park.
C. P. Close, 1906-11; W. R.
Ballard, 1912-18; E. C.
Auchter, 1919-28; W. E.
Whitehouse, 1921-29.
A. L. Schrader, S. W.
Wentworth.
614 YEARBOOK, 1937
Table 4. — Locations and personnel of apple-breeding work in the United Stales — Con.
State, institution, and location
Dato I
begun
Previous workers
Massachusetts:
Agricultural Experiment Station, Am-
herst.
Minnesota:
Agricultural Experiment Station, St. I 1S90
Paul.
Missouri:
State Fruit Experiment Station, Moun-
tain Grove.
Agricultural Experiment Station, Co-
lumbia.
New York:
Agricultural Experiment Station. Ge-
neva.
Ohio:
Agricultural Experiment Station,
Wooster.
South Dakota:
Agricultural Experiment Station,
Brookings.
Virginia:
Agricultural Experiment Station,
Blacksburg.
U. S. Department of Agriculture, Bureau of
Plant Industry:
Arlington, Va.; Beltsville. M<1
Mandan, N. Dafc-
1901
1905
1892
191.5
1895
1910
1912
1915
S. B. Green, Charles Jiaral-
son, M. J. Dorsey, J. II.
Beaumont.
John T. Stinwon, Paul
Evans, F. W. Faurot.
J. C. AVhitten, W.ll. Chan-
dler.
S. A. Beach, 1891-1905
J. B. Keil
Present staff
J. K. Shaw.
W. II. Alderman, A.
N. Wilcox, W. O.
Brierley, E. Angelo,
F. E. Haralson.
Paul H. Shepard.
A. E. Murneek.
U. P. Hedrick, Rich-
ard Wellington, G.
II. Howe, B. B.
Nebel.
F. S. Howlett, C. W.
Ellenwood.
NT. E. Hansen.
A. \V. ]>rinkard, Ir _. : Fred W. HofMann.
C. P. Close.—.
Max Pfaender..
H. P. Gould, J. E.
Magness.
W. P. Baird.
PROGRESS IN
PEAR IMPROVEMENT1
J. R. MAGNESS, Principal Pomologist,
Division of Fruit and Vegetable Crops
and Diseases, Bureau of Plant Industry
X HE pear, like the apple, first came to us from western Asia by way
of European countries. Its history in Europe closely parallels that of
the apple. Apparently indigenous in the region from the Caspian Sea
westward into Europe, whence so many of our fruits came, the pear
was doubtless used as food long before agriculture was developed as
an industry. Hedrick, in the Pears of New York, gives an excellent
summary of its history and development during the last 3,000 years.
Nearly 1,000 years before the Christian Era, Homer listed pears as
one of the fruits in the garden of Alcinous, thus indicating that they
were known to the Greeks of his day. Prior to the Christian Era at
least a few varieties were known. Theophrastus (370-286 B. C.)
mentioned both wild pears and cultivated named varieties and de-
scribed grafting. Pliny, of ancient Rome, named more than 40
varieties. With the migrations of the Romans the pear was distrib-
uted throughout temperate Europe.
At the time of the discovery of North America, a number of varieties
were known in Italy, France, Germany, and England, but there was
little progress in the culture of the pear, at least as far as is known,
from the early Christian Era until about the beginning of the sixteenth
century.
During the eighteenth and nineteenth centuries, there was a tre-
mendous interest in pear breeding and improvement, particularly in
Belgium and France. Hardenpont (1705-74), a priest in Mons,
Belgium, sowed large quantities of pear seeds and introduced a dozen
varieties having soft, melting, buttery flesh. Prior to his time only
types with crisp, breaking flesh were known. Whether or not he
did any hybridizing is not known. Van Mons (1765-1842), a physi-
cian and pharmacist at Louvain, Belgium, developed pear breeding
on a large scale. At one time 80,000 seedlings were growing in his
gardens. He originated or distributed over 400 varieties, 40 of which
have proved of lasting merit.
Many other Belgian and French pear breeders were working on a
smaller scale and introduced varieties of great value. The nineteenth
century may well be considered the golden era of pear breeding in
these countries. Most of the breeding consisted in planting seed of
open-pollinated varieties and in selecting the superior types.
'This report is made possible only through the cooperation ol stall members of the State agricultural
experiment stations conducting pear-breeding investigations. Reports for their respective stations were
submitted by W. H. Chandler and W. P. Tufts, of California; H. P. Stuckey, of Georgia; A. L. Schrader,
of Maryland; A. N. Wilcox, of Minnesota; G. H. Howe, of New York; and F. C. Eeimer, of Oregon.
615
616 YEARBOOK, 1937
The pear in Europe today, derived from Pyrus communis L.,
takes its place beside the apple in total production, in diversity of
varieties, and in popularity. It is far more popular in Europe than
in the United States.
THE PEAR IN NORTH AMERICA
The early history of pear growing in North America parallels that
of apple growing. Pear seed was brought to this country by the
early settlers and possibly trees of some varieties. Pear trees were a
part of the early colonial orchards. The Prince Nursery catalog
listed 42 varieties in 1771.
About that time, however, fire blight or pear blight, the scourge
that has frustrated the development of the pear industry in the
United States ever since, became epidemic. William Denning,
describing the disease in 1794, says he first saw it in 1780 in orchards
of the Hudson Valley. How much earlier it might have occurred
we do not know, neither are we sure where it came from. It seems
most probable that it was present in some native host and became
epidemic only when considerable orchard development occurred.
Not for another century was the cause of the disease known. In
1882, Burrill, at the University of Illinois, discovered the cause of
fire blight to be a bacterium working in the bark tissues.
The disease, which attacks roots, crown, trunk, limbs, blossoms,
fruit, and leaves, proved such a menace that pear growing with vari-
eties from Europe, or with seedlings produced from them, never
developed to a major industry in the eastern United States. Only
in a few sections having relatively cool summers and mild winters
has the culture of the European type of pear been successful in the
Eastern States. Such conditions are found in relatively narrow
strips on the south and east sides of Lake Michigan, Lake Erie, and
Lake Ontario. Elsewhere the warm, humid summers have been so
ALL of the known species of pears are native to Europe, Asia, and
northern Africa. There are no native American species, and none
are known in the Southern Hemisphere. Within these species and
varieties, however, ive have all the characters needed to produce pears
suitable for this continent — fruit of high quality, winter-hardy, and
above all resistant to fire blight, the scourge that has made the grow-
ing of superior pears impossible throughout much of the United
States and difficult even in favored regions. To combine these
characters properly constitutes a great challenge to the American
plant breeder. He has made a small but promising start, and if,
with the raw materials available, the problem is not solved within
the next century, it will indeed be a reflection on his scientific
ability and energy.
PEARS
617
favorable for fire blight that the development of commercial orchards
with these types of pears has not been very successful (fig. 1).
An event of great importance from the standpoint of eastern pear
growing was the introduction of the Chinese or sand pear into the
United States. The sand pear (Pyrus serotina Rehd.) was growing in
the United States by 1840, apparently having come in by way of
Europe. These pears are relatively resistant to blight. They are
coarse-fleshed, generally contain many grit cells, and are themselves
of very inferior quality. Because of their blight resistance, however,
they were rather widely disseminated over the eastern United States.
Figure 1. — Pear orchard destroyed by fire blight.
Soon hybrids between the sand pear and P. communis varieties began
to appear. The Le Conte, Kieffer, Garber, Douglas, and more
recently the Pineapple, are the most important of these hybrids.
All of these are very inferior in quality as compared to the "buttery"
pears of Europe. They are sufficiently resistant to blight, however,
to permit growing in most parts of the eastern United States. They
are widely planted in home orchards and in small commercial orchards
at the present time.
Another event of importance was the importation of a large number
of varieties from northern Russia. Since 1879, when the first ship-
ment was made, 70 to 80 varieties have been brought in and tested in
Iowa and other northern sections. These are hardy but generally
poor in quality and very subject to blight. They are of value only
for breeding for hardiness, and probably some of the oriental types
that combine hardiness and blight resistance are superior for this
purpose.
138904°
-10
618 YEARBOOK, 1937
In the United States the greatest development of pear growing has
centered in the moderately warm, dry valleys of the three Pacific
Coast States. Pears were established in California long before that
State became a part of the Union, having been introduced by the
Mission Fathers with the earliest white, settlements. In the valleys
of the Pacific States, where there is little summer rainfall and the
nights are relatively cool, fire blight is less rampant than in the eastern
United States. Most of the European varieties reach a high degree
of perfection in these areas. Although blight is a constant menace
in many of the sections at the present time, methods have been devel-
oped so that it is possible to control it commercially, chiefly by means
of careful surgery.
The principal pear varieties grown in the United States today are
listed in the appendix, with notes on their origin.
It is apparent that, in contrast to apples, our highest quality pear
varieties have mainly been imported directly from Europe. The
most important — Bartlett, Anjou, Bosc, and Winter Nelis — are all
direct European importations. Among our leading varieties, only
those selected primarily because of blight resistance have originated
in the United States. These include Seckel, a blight-resistant variety
apparently of straight Pyrus communis origin, and the P. communis
X P- serotina hybrids. European breeders have worked with pears to
a far greater extent than with apples, and in all respects except resist-
ance to fire blight their best varieties have so far proved superior to
those that have developed as chance seedlings in the United States.
Objectives in Pear Breeding in the United States
One objective stands out above all others in the breeding of pears
in the United States. This is to secure resistance to fire blight, com-
bined with satisfactory dessert quality. In few regions east of the
Rocky Mountains can varieties be grown successfully unless they have
a fairly high degree of blight resistance. Varieties available at the
present time that have fair blight resistance — primarily Pyrus com-
munis X P- serotina hybrids — are all of inferior quality as compared
to the better P. communis varieties. The securing of blight resistance
coupled with quality is important in every section of the United States
and is the predominent need in at least three-fourths of the potential
pear-growing territory of the country.
A second and more localized objective is the securing of additional
hardiness in pear varieties for growing in the northern Great Plains
and other areas that have very cold winters. Varieties of Pyrus
communis having good dessert quality do not possess sufficient hardi-
ness to thrive in those regions.
Blight-resistant varieties are needed that also have high dessert and
culinary quality and that ripen at intervals from early summer until
late fall. Late-ripening varieties with good storage quality are espe-
cially needed. At the present time no varieties are available that have
theso characteristics and are adapted for growing east of the Rocky
Mountains. Varieties of European origin meeting these qualifications
are grown successfully in the Western States, but even there the prob-
lem of blight control is of tremendous importance and involves a
heavy expense to growers.
PEARS 619
Rootstocks are also needed that combine blight resistance with
satisfactory hardiness, congeniality to scions, and adaptation to
environment. Fire blight frequently attacks the roots as well as the
tops of the trees, and rootstocks that are blight-resistant are a primary
need in most regions of the United States where pear growing is
attempted.
Material Available for Pear Breeding in the United States
The cultivated pear varieties of Europe, derived from Pyrus com-
munis, generally produce fruit of high quality. Superior varieties pro-
duced by European breeders have the buttery texture, relative free-
dom from grit cells, and aromatic to spicy flavors needed in pears of
high quality. While these varieties vary considerably in blight resist-
ance, none of the high-quality European sorts are known to be suffi-
ciently resistant to thrive in the regions where blight is most serious.
The snow pear, Pyrus nivalis Jacq., native to southern Europe and
cultivated there for making perry, the fermented pear juice popular
as a beverage in Europe, is not cultivated in the United States. Trees
of this species arc very susceptible to blight, and it appears to have
little merit as breeding material except possibly for developing perry
types if a perry industry should be built up in this country.
The sand pear, Pyrus seroiina, is native to central and eastern China
and is cultivated in China and Japan. The fruit is heavily russeted
and commonly apple-shaped, and the flesh is very gritty. Trees of
this species are variable in resistance to fire blight but on the average
much more resistant than P. communis. It hybridizes freely with P.
communis varieties, and several of the hybrids are important American
varieties because of their blight resistance, although all are lacking in
quality.
The Ussurian pear, Pyrus ussuriensis Maxim., is native to northern
China and eastern Siberia. This is the hardiest of pears. The tree is
a rather slow grower but very resistant to blight. It is cultivated, and
a number of varieties are known in its native habitat. The best of
these varieties are soft-fleshed, not excessively gritty, juicy, and sub-
acid to acid in flavor. The trees bloom very early. This appears to
be an extremely valuable species for breeding to obtain blight resistance
and hardiness.
The Callery pear, Pyrus calhryana Decne., is native to central China.
The trees are medium to large, vigorous, and bloom early. The fruit
is small and seems valueless. The trees are very blight-resistant and
may be valuable as stocks for regions having mild winters. They are
of questionable hardiness for the colder sections.
The birchleaf pear, Pyrus betulaefolia- Bunge, is native to central and
northern China. The tree is large and vigorous. It blossoms late and
produces small, valueless fruit. Many trees of this spocies are quite
susceptible to blight, but there are some resistant types. This species
propagates readily from root cuttings, so the blight-resistant types are
of possible value for rootstock purposes.
Although there are several other species — a total of 20 to 25 accord-
ing to the usual botanical classifications — the 6 listed above seem to
be of greatest economic importance. All of these species will, so far as
known, hybridize readily among themselves.
620
YEARBOOK, 1937
It is of interest to note that all of the known species of pears are
native in Europe, Asia, and northern Africa. There are no native
American species; neither are any known in the Southern Hemisphere.
Within these species and their varieties we have all of the characters —
high-quality fruit, blight resistance, and hardiness — needed to produce
pear varieties suitable for North American conditions. To combine
these characters in varieties adapted to the different regions of the
United States constitutes a great challenge to the American plant
breeder. Only a small start has been made on this problem. With the
raw materials available, however,
if American plant breeders do not
\ A. i solve this problem within the next
century it will indeed be a reflec-
tion on their scientific ability and
K^/^ energy.
Pear-Breeding Work Now m
Progress in the United States
The technique of collecting
pollen, emasculating blossoms
(fig. 2), and cross-pollinating in
pears is in all respects similar to
that already outlined for apples.
Pear breeding at the California
Agricultural Experiment Station
was started in 1928. The objec-
tive is to obtain superior Pyrus
communis varieties ripening at
intervals throughout the season,
including some with good storage
quality for holding through the
winter months. Approximately
1 ,700 open-pollinated seedlings of
the leading P. communis varie-
ties are being grown. In 1931,
crosses to give approximately
3,000 seedlings were made. These
consisted of Bartlett crossed with Winter Nelis, Easter Beurre, Cornice,
Hardy, Anjou, P. Barry, and Bosc.
At the Georgia Experiment Station at Experiment, Ga., a consider-
able collection of varieties is maintained and studied for resistance to
blight. Active breeding wrork is not under way. The variety Sowega,
introduced in 1930 by J. J. Parish, Adel, Ga., is reported to be of high
quality and very resistant to blight.
Pear-breeding work in Iowa was started by C. G. Patten shortly
after 1867. The assistance Patten received from public institutions
has been outlined briefly in connection with his work with apples.
Patten's work was significant in demonstrating the possibility of de-
veloping pears sufficiently hardy to thrive in the upper Mississippi
Valley. He grew a large number of open-pollinated seedlings of Pyrus
ussuriensis. This oriental pear was growing adjacent to P. communis
varieties, and many of the seedlings are obviously hybrids. The
Figure 2.-Ulossoming spurs of pear, in prop
it stage of development for emasculation
PEARS 621
seedling trees were more vigorous than the original P. ussuriensis and
proved as "hardy as an oak." These hybrids have proved more hardy
in tests during the last 20 years than pears from any other source.
Twenty-five of Patten's seedling pears have been selected for further
breeding work. One variety, the Patten, a cross of Orel 15 X Anjou,
was introduced by the Iowa Agricultural Experiment Station in 1922.
Crosses and backcrosses of Patten's seedlings with P. communis va-
rieties were made between 1918 and 1928. Much of this work was
lost when it was necessary to abandon the station in 1932.
Pear-breeding work at the University of Maryland, College Park,
was begun in 1905. Hybrids consisted mainly of crosses of Kicffer
with Pyrus communis varieties, particularly Seckel arid Anjou, al-
though a few crosses of P. communis X P. communis were made. A
total of 1,411 seedlings from crosses made* between 1905 and 1917 have
been grown to fruiting. Only one, a Kieffcr-Anjou hybrid, seems to
have merit. A number of these hybrids are being maintained for fur-
ther determination of their blight resistance.
In Michigan during the period between 1916 and 1919, W. F. Wight
and Don Ward, of the United States Department of Agriculture, hy-
bridized pears at the South Haven Horticultural Experiment Station
at South Haven. These hybrids were grown to fruiting cooperatively
by the Department and the South Haven station. The parents were
for the most part moderately blight-resistant types of good quality.
Of all the crosses made, Barseck X Bartlett has been most outstanding.
A number of the progeny of this cross have produced pears of excellent
quality, apparently with some blight resistance, the degree of which
has not been satisfactorily determined. A number of these selections
are under test in Michigan and at the United States Horticultural
Station at Beltsville, Md.
A limited amount of breeding work was started at the Minnesota
Agricultural Experiment Station in 1908. The primary objective has
been to obtain hardiness and blight resistance. In that year, 300
seedlings of an unknown variety from Manchuria were planted. Two
of these have been selected as of horticultural value. Since 1924, a
considerable number of hybrids of Pyrus communis X P- ussuriensis
have been made. These are grown in the field without any protection,
and only the hardiest survive for planting in the trial orchards.
Approximately 700 of these seedlings have survived the Minnesota
winters and are being grown to fruiting.
Pear breeding at the New York (State) Agricultural Experiment
Station at Geneva started in 1892. Relatively few seedlings were
grown before 1906. By 1921, 1,775 seedlings had been grown, most
of which have fruited. Approximately 5,000 seedlings have been set
out since 1921, of which only a few have fruited as yet. The varieties
used in crossing and the number of times they were used are as follows:
Anjou, 31;Bosc, 59 ; Bartlett, 85 ; P. Barry, 1 1 ; Clairgeau, 16; Cayuga,
16; Dana Hovey, 12; Ewart, 10; Gorham, 13; Kieffer, 24; Lincoln
Coreless, 12 ; Ovid, 9 ; Phelps, 35 ; Pulteney, 41 ; Seckel, 77 ; Sheldon, 20 ;
Tyson, 28; Winter Nelis, 17; and Willard, 17. The New York work
has consisted primarily in the hybridizing of Pyrus communis varieties
to produce high-quality types. The objective has been to obtain pears
equal to Bartlett in size, appearance, and quality, but ripening through
622
YEARBOOK, 1937
a long season. Recently, added emphasis has been placed on the testing
of all seedlings for blight resistance. The varieties introduced as a re-
sult of the breeding work in New York State are listed in the appendix.
By far the most extensive project in the United States on the testing
of known varieties and species of pears for their resistance to blight
has been conducted nt the Southern Oregon Branch Experiment
Station, Talent, Oreg. (fig. 3).
Tests have included practically all
of the known species, as well as a
number of the Asiatic varieties of
Pyrus serotina and P. ussuriensis.
Eighty-five P. communis varieties
and hybrids have been inoculated
repeatedly, while 500 pear varieties
have been grown in orchard form
where they were exposed to natural
infection from great quantities of
blight in the orchard. The earlier
results of these experiments are re-
corded by Reimer (7).z This work
gives much information on the rel-
ative blight resistance of various
Pyrus species and varieties and in-
dicates clearly the material of
greatest value for breeding for
blight resistance.
The present work has two ob-
jectives— (1) to develop depend-
able, hardy, congenial, blight-re-
sistant rootstocks for pears; and
(2) to develop high-quality, blight-
resistant varieties. Ba Li Hsiang,
a highly resistant Pyrus ussurien-
sis variety, pollinated with another resistant variety, gave seedlings suf-
ficiently blight-resistant for rootstocks, but such seedlings have proved
unsatisfactory for some of the commercial P. communis varieties and
have been discarded. Seedlings of P. calleryana resulting from resistant
trees planted so that both pollen and seed parents are resistant have
proved highly resistant to blight and appear to be excellent rootstocks
in southern Oregon. They may lack sufficient hardiness for the colder
sections of the country. By mass selection methods, seedlings of P.
communis have been found resistant to blight. From 10,000 seedlings,
10 proved highly resistant, and these 10, when pollinated with other
resistant varieties, transmit a high degree of resistance. Three of these
have produced seedlings 100-percent resistant to root blight when pol-
linated with another resistant type.
In breeding for resistant varieties of high quality, varieties of Pyrus
ussuriensis crossed with Anjou, Bartlett, Bosc, and Cornice have given
only poor-quality varieties, and all have been discarded, though a
part of the seedlings were blight-resistant.
Figure 3. — F. C. Reimer, whose extensive
work in determining the extent of blight
resistance in practically all known species
and varieties of pears serves as a foundation
in breeding for blight resistance.
1 italic numbers in parentheses refer to Selected References to Literature, p. 627.
PEAKS
623
In 1915, Rcimer saw a small Anjou seedling on Benjamin Buck-
man's farm at Farmingdale, 111., which was just coming into bearing,
with fruit of good size and mediocre quality. The tree was free from
blight while the disease was rampant in other varieties surrounding it.
Scion wood was obtained and the tree propagated at the Southern
Oregon Experiment Station. Extensive inoculation work at the
station has proved that this tree is highly resistant to blight. Buck-
man named the tree Farmingdale
in honor of his town.
During the last 5 years several
thousand trees have been pro-
duced which are crosses between
FarmingdaleandAnjou,Bartlett,
Bosc, Cornice, and Seckel. Ap-
proximately 75 percent of these
seedlings have blighted when
inoculated. The remainder have
so far proved highly resistant
even when repeatedly inoculated .
The oldest of these crosses should
come into bearing during the next
year or two. It is hoped that
among these resistant trees at
least a small number will possess
the good quality of the fine-
flavored varieties used as one
parent in each cross and the
blight resistance of the Farming-
dale.
With one exception, all the
crosses have proved vigorous.
This one exception is Anjou X
Farmingdale, these seedlings be-
ing only moderately vigorous.
Furthermore, the leaves of 20
percent of the seedlings residting
from this cross possessed a waxy white color (devoid of chlorophyll),
and the seedlings died when they were from 2 to 4 inches high. This
is probably the result of inbreeding, since Farmingdale itself is a
seedling of Anjou.
Breeding work to obtain pear varieties resistant to blight was
started at the Tennessee Agricultural Experiment Station in 1925,
though a limited amount of hybridizing had been carried on earlier.
The work since 1925 has consisted of crossing resistant species such
as Pyrus serotina, P. vssuriensis, and P. calleryana with the more
resistant varieties of P. communis. Approximately 3,000 seedlings
from these crosses are now being grown, and additional hybridization
is under way.
In the United States Department of Agriculture breeding investi-
gations to develop pear varieties resistant to fire blight were started
Figure I. — Merlon H. Waite, whose experi-
ments in the United States Department of
Agriculture showing the necessity for
cross-pollination in horticultural varieties of
pears led the way to the great amount of
research conducted since, not alone with
I>ears but with all orchard fruits. He was
also an early leader in breeding pears for
blight resistance.
624
YEARBOOK, 1937
by M. B. Waite at the Arlington Experiment Farm, Arlington, Va.,
about 1908 (fig. 4). The early work consisted of crossing Kieffer
with Seckel, Anjou, and Bartlett. Several thousand seedlings from
these crosses have been grown to fruiting. Several selections made
from these earlier seedlings combine good fruit quality with blight
resistance. At least one selection seems to be very blight-resistant
and has good fruit characters from the standpoint of flesh texture,
1'igure 5. — Hybrid pear seedlings growing in the greenhouse.
size, and quality. None of the selections has been named, but they are
worthy of general testing. At the present time, around 5,000 seed-
lings from the above crosses are being grown to fruiting (fig. 5).
These are inoculated with blight each year in addition to being
exposed to field infection. Resistance to blight, resistance to leaf
spot, and fruit characters are being recorded.
A few crosses between high-quality Pyrus communis varieties have
been made at Palo Alto, Calif., by W. F. Wight, of the United States
Department of Agriculture. The purpose in these crosses is to obtain
pears of high dessert quality, ripening at intervals through the slim-
mer, and also varieties suitable for winter storage.
A list of pear material of special value for breeding purposes,
with the institutions at which it is maintained, is given in the
appendix. Some of the results of hybridization are illustrated in
figure 6.
For a discussion of pear-breeding work under way in other countries,
see pages 602-604.
PEARS
625
Figure 6. — The fruils of hybridization: A, liartlett pear (Pyrus communis); B, KiefTer
a hybrid of P. serotina X P. communis; C, hybrid variety from a croas of Kieffer X
Bartlett.
626 YEARBOOK, 1937
CYTOLOGY AND GENETICS OF THE PEAR3
The basic chromosome number in the germ cells of pear species is 17,
the same as that of the apple. Among European varieties, approxi-
mately one-fourth to one-third of those examined to date are triploids,
this ratio being about the same as for apples in the United States.
These forms with 51 somatic chromosomes, like the triploid apples,
generally produce only a small percentage of viable pollen. According
to unpublished data from the New York (State) Agricultural Experi-
ment Station, all of the pear varieties important in the United States are
diploids with 34 chromosomes in the vegetative tissues. Most of these
diploid varieties produce a relatively high percentage of viable pollen.
Recently two bud mutations that may be tetraploids have been
found in pears, one in Bartlett, the other in Winter Nelis. These
produce giant fruit similar in general appearance to the parent variety
but coarser textured. In the case of the Bartlett at least, the fruit
is inferior in quality to the parent variety. If cytological examina-
tion proves these to be true tetraploids, they may prove to be of
much interest and value from the standpoint of breeding, as crosses
of tetraploids with diploid varieties should produce triploids.
Few studies have been reported to indicate the type of inheritance
that may be expected in pears. Since all varieties of Pyrus communis
are highly heterogeneous, and since selfing in most varieties is im-
practicable because of failure of self-pollinated blossoms to produce
viable seed, inheritance studies are difficult.
Size of fruit appears to be controlled by many factors. Seckel
gives mainly small-sized fruits even when hybridized with large-fruited
types, though many intermediate-sized fruits are found in the progeny,
a few approaching the size of the larger parent.
The low quality of oriental pears seems to be dominant over high
quality of other groups, though intermediate forms sometimes are
found. No high-quality progeny has occurred in Fi hybrids of Pyrus
serotina X P- communis or P. ussuriensis X P- communis. In back-
crosses of these Fi hybrids with high-quality P. communis varieties,
some good-quality types result. In 11 trees from Kieffer (P. communis
X P. serotina) X Anjou, fruited in 1936 by the Bureau of Plant Indus-
try, fruits of 2 rated good and 4 fair to good. In 132 Kieffer X Seckel
hybrids, fruit of 17 rated as good and 24 as fair to good in quality.
Kieffer, a sand pear hybrid, probably carries russet as a recessive
character. In the crosses with russeted Seckel, 23 hybrids were heavily
russeted, 45 semirusseted, and 64 smooth. These results indicate that
in this cross russet is recessive to smooth skin. Kikuchi has reported
that within Pyrus serotina, russet behaves as a dominant. In 122
Kieffer (subacid) X Seckel (sweet) hybrids, 26 produced sweet fruit,
like Seckel, 82 subacid fruit, and 14 acid fruit. These results would
indicate that, as in apples, sweetness tends to be recessive but that the
character is controlled by more than one gene.
No study has yet been reported on the transmission of blight
resistance. Reimer finds wide variability in blight resistance of
individual seedlings of most of the species studied, with occasional
blight resistance appearing in all species studied. Crosses of highly
3 This section is written primarily for students or others professionally interested in breeding or genetics.
PEARS
627
resistant Farmingdale with blight-susceptible varieties have resulted
in about 25 percent blight-resistant seedlings in the Ft progenies.
SELECTED REFERENCES TO LITERATURE
(1) Cox, H. R.
1913. oriental peaks and THEiu hybrids. N. Y. (Cornell) Agr. Expt.
Sta. Bull. 332, pp. 445-486, illus.
(2) Crane, M. B., and Lawrence, W. J. C.
1934. THE GENETICS OP GARDEN PLANTS. 236 pp., illuS. London.
(3) Florin, R.
1927. pollen production and incompatibilities in apples and pears.
N. Y. Hort. Soc, Mem. 3: 87-118, illus.
(4) Hedrick, TJ. P., assisted by Howe, G. 11., Taylor, O. M., Francis, 10. H.,
and Tukey, II. B.
1921. the pears of new york. 036 pp., illus. Albany. (N. Y. Dept.
Agr. Ann. Rept. 29, v. 2, pt, 2.)
(5) Lantz, H. L.
1929. pear breeding: an inheritance study or pyrus communis X
p. ussuriensis hybrid fruits. Amer. Soc. Hort. Sci. Proc. 26:
13-19.
(6) Moffett, A. A.
1933. cytological studies in cultivated pears. Genetiea 15: [511J-518,
illus.
(7) Reimer, F. C.
1925. blight resistance in pears and characteristics of pear species
and stocks. Oreg. Agr. Expt. Sta. Bull. 214, 99 pp., illus.
(8) Tufts, W. P.
1919. pollination of the bartlett pear. Calif. Agr. Expt. Sta. Bull.
307, 369-390, illus.
(9) Waite, M. B.
1895. the pollination or pear flowers. U. S. Dept. Agr., Div. Vege-
table Path. Bull. 5, 108 pp., illus.
APPENDIX
Table 1. — Leading pear varieties of the United Slates
Variety
Angoulerne-
Anjou
Bartlett.
Parent species
Pyrus co-mmunis..
do
.do..
.do.
Bosc
Clairgeau -do..
Clapp Favorite ! do..
Cornice ! do..
Dana Hovey : do
Douglas ; (P. communis X sero-
tina) X P- communis
Kieffer X Angouleme.
Easter Buerrf i Pyrus communis
Flemish Beauty.
Forelle.
Garber.
Qlou Morceau..
Hardy
.do..
-do_.
Pyrus communis X sero-
tina.
Pyrus communis
.do-
By whom, where, and how originated
Wild seedling, Angers, France. Propagated 180S, in-
troduced into the United States before 1830.
A seedling of Van Mons, according to Bunyard. An
old French variety, according to Hedrick. Introduced
into the United States 1842.
Raised by a Mr. Stair at Aldermaston, Berkshire, Eng-
land, about 1770. Brought to the United Slates about
1797.
A Van Mons variety, 1807. Introduced into the United
States in 1832.
Raised by Pierre Clairgeau, Nantes, France, about 1830.
Introduced into the United States 1854.
Thaddeus Clapp, Dorchester, Mass. Reported Massa-
chusetts Horticultural Society, 1800.
Cornice Horticolc, Angers, France, 1849. Introduced
into the United Stales in 1850.
Francis Dana, Roxbury, Mass. Introduced 1854.
O. II. Ayer, Lawrence, Kans., about 1897.
Capucin Monastery, Louvain, Belgium, about 1823;
the United States by 1837.
Wild pear found by M. Chatillon, Alost, Belgium.
Introduced by Van Mons 181£; into the United States
about 1830.
Germany about 1700, the United States 1823.
J. B. Garber, Columbia, Pa., before 1880.
M. Hardenpout, Mons, Belgium, about 1750, the United
States about 1820.
M. Bonnet, Boulogne-sur-Merd., France, about 1820.
Introduced into the United States before 1802.
628 YEARBOOK, 1937
Table 1. — Leading pear varieties of the United States — Continued
Variety-
Parent species
By whom, where, and how originated
Howell-
Idaho. _
Kierter.
Le Conte...
P. Barry..
Pineapple.
Seckel—
Sheldon.
Vermont Beauty.
Wilder Early-
Winter Nelis.
Pyrus communis..
..._do
Pyrus communis X sero-
tina.
(Probably sand pear X
Bartlett.)
Pyrus communis X sero-
tinn.
Pyrus communis
Pyrus eerotina X com-
munis.
Pyrus communis.
do
_do.
-do.
.do_.
Thomas Howell, New Haven, Conn., from seed of Jonah
planted about 1830.
Seed planted by Mrs. Mulkey, Lewiston, Idaho, about
1867.
Raised from sand pear seed by Peter Kieffer, Roxbor-
ough, Pa., about 1863.
Originated in the United Slates before 1850. Exact
history unknown.
Seedling of Belle Lucrative, raised by B. S. Fox, San
Jose, Calif.; fruited 1873.
Large seedling tree on plantation of Mrs. B. N. Stuckey,
Nesmitb, S. C; possibly brought in from China or
Japan.
Chance seedling near Philadelphia about 1800.
Premises of Major Sheldon, Huron, N. Y., from seed
planted about 1815.
Seedling in nursery of B. Macombcr, Grand Isle, Vt.,
about 1880. Iledrick says It is indistinguishable from
Porelle.
Chance seedling found by Charles A. Green in Chau-
tauqua Co., N. Y., about 1884.
Raised from seed by Jean C. Nelis, Mechlin, Belgium,
about 1800.
Table 2. — Pear varieties introduced by the New York (State) Experiment Station
Variety
Parentage
Year
crossed
Date
intro-
duced
Value
Cayuga
Clyde
1006
1008
1912
1006
1910
1912
1912
1912
1912
1920
1932
1935
1935
1923
1931
1925
1025
1931
do -_
Bartlett X Dorset .-
Home and roadside markets.
Commercial market.
Ovid
Bartlett X Dorset .. ,..
Phelps
do
Willard.
Bartlett X Dorsett
Table 3. — Workers on pear breeding in the United States
Institution
Location of work
Former workers
Present workers
California Agricultural Experi-
ment Station.
Iowa Agricultural Experiment
Station.
Maryland Agricultural Experi-
ment Station.
Michigan Agricultural Experi-
ment Station and Depart-
ment of Agriculture.
Minnesota Agricultural Experi-
ment Station.
New York State Agricultural
Experiment Station.
Oregon Agricultural Experi-
ment Station.
Tennessee Agricultural Experi-
ment Station.
TJ. S. Department of Agriculture
Berkeley, Calif.;
Davis, Calif.
Ames, Iowa'
College Park, Md
South Haven, Mich...
St. Paul, Minn _.
Geneva, N. Y
Talent, Oreg
Knoxville, Tenn
Beltsville, Md.; Palo
Alto, Calif.
C. G. Patten
C. P. Close, W. R.
Ballard, E. C.
Auchter, W. E.
Whitehouse.
W. F. Wight, Don
Ward.
S. A. Beach.
J. A. McClintock.
M. B. Waite _
W. H. Chandler, W.
P. Tufts.
T. J. Maney, D. S.
Pickett.
A. L. Schrader, S. W.
Wentworth.
Stnnley Johnston.
A. N. Wilcox, W. H.
Alderman.
U. P. Hedrick, Rich-
ard Wellington, G.
H. Howe.
P. C. Reimer.
B. D. Drain.
J. R. Magness, W. F.
Wight.
1 Prior to 1932, at State Fruit Farm, Charles City, Iowa.
PEARS 629
Lists of Peak Material of Special Value for Breedixg Purposes
The following institutions have trees of practically all of the Pyrus species:
Arnold Arboretum, Harvard University, Jamaica Plain, Mass.
California Agricultural Experiment Station, Davis, Calif.
Southern Oregon Branch Experiment Station, Talent, Oreg.
At the California Station the following varieties not generally available are
growing:
Pyrus communis: Marillat,
Bollweiller, Messiro,
Bonncfond, Nantes,
Bordeaux, Remy Chatenay,
Burkett, Sageret,
Caisson, Souvenir de Cronstadt,
Crocker, Superfin,
Felix Sahuit, Thirriott.
Guyot,
Lady Clapp,
P. sinensis:
Largo Sugar, Pin Li (P. I. 38263),
Longworth, P. I. 40352,
Lowe Seedling, Nanshi (P. I. 30352).
At the Minnesota Agricultural Experiment Station, St. Paul, Minn., the
following material has been tested for hardiness under field conditions, with the
results indicated:
1. Completely winter-hardy, tested 10 to 15 years:
Minn. Nos. 3 and 4,
Minn. Nos. 5, 0, and 7 (seedlings of King Karl X sand pear),
Phiel,
Russian sand pear,
Saponsky.
2. Completely winter-hardy, tested 5 years:
Borgman,
Cepe Zum Mur (Russia),
Patten Nos. 5, 1204, 1205.
3. Completely wintor-liardy during tests of 3 to 5 years:
Pushken,
Pyrus communis L., P. I. 47093 et a!.,
P. ussuriensis ovoidea Rehd., P. I. 44051,
P. ussuriensis Maxim., P. I. 44235, 44237, 44275, et al.,
Scandinavian varieties (top-worked branches only):
Aldonspare,
Esperen Herripare,
Furstligt Tafclparon,
Graparo,
Grev. A. D. Moltke,
Johantorp,
Juli Dekan,
Liibecker Prinzessinpare,
Rostbergersmott.
4. Relatively winter-hardv during tests of 3 or more vears:
P. betulifolia Bunge, P. I. 39547,
P brestschneideri Rehd.,
P. communis L., P. I. 33207 ct al.,
P. phaeocarpa Rehd., P. I. 32741, 39541, 43185, 44270,
Pyrus sp., "Favorita," P. I. 33207,
P. ussuriensis Maxim., P. I. 47094, 55907, 55970,
Van Fleet hybrid, P. I. 43443.
5. Relatively hardy, but not completely hardy in Minnesota; tested 5 years or
more:
Beierschmitt, Patten Nos. 1200, 1206,
Chang, Simola,
Mendel, Tait, Nos. 1, 2, and 4.
Parker,
630
YEARBOOK, 1937
6. Other species, severely winter-injured but surviving:
P. calleryana Decne., P. I. 47261,
P. chinensis,
P. phaeoearpa Rchd., P. I. 64229,
Pyrus sp., "Surprise," P. I. 45901,
Pyrus sp., P. I. 46566, 56012, 64223,
Pyrus sp., Van Fleet hybrid, P. I. 55805,
P. ussuriensis Maxim., P. I. 46587.
The New York (State) Agricultural Experiment Station, Geneva, N. Y., has
the following pear varieties that are not generally available in the United States: 4
Admiral Gervais, P. I. 91198,
Alexander Lambrc, P. I. 91199,
Ba Li Hsaing,
Barronne de Mello,
Baudry,
Belle Gu6randaise, P. I. 91200,
Beurre d'Arenbcrg (syn. of
Morceau),
Beurr<§ Bedford,
Beurre Cadelien,
Beurre Dumont
Beurre Fouqueray,
Beurre Six (P. I. 91201),
Ewart,
Favorita,
Fondante Thirriot,
Gdula,
HessleJ
Lung Li, P. I. 46587,
Koestliche von Charmeau,
Kontoula, P. I. 47227,
Laxton,
Laxton Superb,
Louis Pasteur,
Mario Benoist,
Michurins,
Ming,
Ne Plus Meuris,
Glou Noveau Poitcau, P. I. 91207,
Nouvelle Fulvic,
Packham Triumph,
Passe Crassanc,
Pastoren Birne (syn. of Vicar of Wink-
field),
Petite Marguerite, P. I. 91208,
Petre,
President Barabe, P. I. 91209,
Satisfaction,
Soldat Laboureur, P. I. 91210,
Tang Li,
Triomphe do Vionne,
Vergules,
Miscellaneous Pyrus species.
At the Southern Oregon Branch Experiment Station, Talent, Oreg., 500 varie-
ties of pears have been collected. Some of these have died of blight and are no
longer available. These are listed in Oregon Station Bulletin 214.
' Names are substantially as submitted by the station. Some are not in full accord with tlie code of
nomenclature.
GRAPE DEVELOPMENT
AND IMPROVEMENT
ELMER SNYDER, Pomologisl, Divi-
sion of Fruit and Vegetable Crops and
Diseases. Bureau of Plant Industry 1
JL HE present commercial grape industry in the United States has de-
veloped along two main lines. On the Pacific coast the industry has
depended upon the importation and improvement of varieties of the
grape of the Old World, Vitis vinifera L., while in the remainder of
the country the industry has been based upon the development of the
American species indigenous to the region, hybrids of these species,
and finally hybrids of native species with V. vinifera. On the other
hand, the industry in the Old World originated actively from the single
species V. vinifera. This species has also played a vital part in the
improvement of our native grapes. It was known in prehistoric
times. Sacred writings and ancient myths and fables extol the value
of this grape. Seeds of the grape have been found in the remains of
lake dwellings of the Bronze Age in Switzerland and Italy and in the
tombs of ancient Egypt. Remains of grape leaves have also been
found in calcareous rocks in Prance, where they were apparently de-
posited in prehistoric times. It is the belief of botanists that the
ancient home of this species was the Caspian Sea region.
DISTRIBUTION AND EARLY HISTORY
From its original habitat the grape was carried westward into favorable
locations in Africa and Europe and eastward in Asia. The distribution
of the species by birds, wind, and water undoubtedly began very early,
even before cultivation, and possibly before the existence of man in
Asia or Europe. Grape growing was practiced very early in Palestine,
and cultural material was transported by the early Phoenician naviga-
tors to the countries bordering on the Mediterranean Sea. According
to Alphonse de Candolle, records of the cultivation of the grapevine
and the making of wine in Egypt go-back 5,000 to 6,000 years. Viti-
culture in Greece was flourishing during the time of Homer and must
'The writer wishes to acknowledge the cooperation of the many workers on grape breeding who have
supplied the data on which a portion of this report is based. The following have supplied data relative
to grape-breeding work in their respective countries: Ing. Fr. Landovsky, State Institute for Horticultural
Eesearch, Pruhonice, Czechoslovakia; Dr. J. Dufrenoy, Station de Pathologie Vegetale, Pont de laMaye,
Prance; Prof. Giovanni Dalmasso, director, Stazione Sperimentale di Viticoltura e di Enologia, Conegliauo,
Italy; and Prof. Dr. Rudorf, director. Kaiser Wilhelm-Ins'titut fur Ziichtungsforschung, Miincheberg,
Germany. In the United States the following workers have furnished data on their grape-breeding investi-
gations; H. P. Olmo, California Agricultural Experiment Station, Davis, Calif.; H. P. Stnckey, Georgia
Experiment Station, Experiment, Ga.; A. L. Schrader, Maryland Agricultural Experiment Station, College
Park, Ml; A. N. Wilcox, Minnesota Agricultural Experiment Station, St. Paul, Minn.; Paul H. Shepard,
Missouri State Fruit Experiment Station, Mountain Grove, Mo.; Richard Wellington, L. M. Van Alstyne,
and B. R. Nebel, New York (State) Agricultural Experiment Station, Geneva, N. Y.; P. E. Gladwin,
Vineyard Substation of the State station, Fredonia, N. Y.; S. H. Yarnell, Texas Agricultural Experiment
Station, College Station, Tex.; Fred W. HofMann, Virginia Agricultural Experiment Station, Blacksburg,
Va.; C. A. Magoon and I. W. Dix, U. S. Horticultural Station, National Agricultural Research Center,
Beltsville, Md.; and Charles Dearing, Coastal Plain Branch Station, Willard, N. C.
631
632 YEARBOOK, 1937
have been known before his time. The Komans doubtless gained
their knowledge of grape growing and the art of wine making from the
Greeks. For a time the Romans seemed to prefer the Grecian product,
and not until about the first century of the Christian Era did Italian
wines begin to have a favorable reputation in their own region.
In the meantime French viticulture was originating in the vicinity
of what is now Marseilles and spreading up the valley of the Rhone.
In the second century A. D . it had spread along the banks of the Rhine.
From a centralized beginning the growing of Vitis vinifera has gradually
spread until at the present time it is grown commercially in parts of
Europe, Asia, Africa, Australia, North America, and South America.
Grape growing is practiced in the Northern Hemisphere mainly
between 20° and 51° N. latitude, and varieties of Vitis vinifera, arc
found in many of the countries bounded by these parallels. The most
northern range of the varieties of Vitis vinifera is in the grape area
of northern Germany, while the southern range extends into India.
In the Southern Hemisphere, including Australia, South Africa, and
South America, grape growing is carried on mainly between 20°
and 40° S. latitude.
Introduction of Old World Grapes
Into the United States
American colonists at a very early period understood the culture
of the vine. The abundance of native grapevines along the Atlantic
coast attracted their attention, but the first attempts, made early
THE major portion of the grape-breeding work conducted by public
institutions has been to improve quality, which is an elusive factor.
The quality of our native varieties has been improved by crossing
them with the best varieties of the European grape. Improvements
in type of cluster and type of berry have been made by combining
different native species. Rootstocks have been developed through
hybridization which have suitable resistance to phylloxera, the
deadly insect enemy of the grape, and are adapted to various soil
types. Thus real progress has been made. But continued im-
provement is possible, and the results so far indicate that it can be
obtained through hybridization. Grape breeding is relatively new,
and there is need for more information on the inheritance of such
characteristics as size, quality, seedlessness, cold hardiness, disease
and insect resistance, and adaptability to environment. Rich
collections of species and varieties are available as breeding material
to bring about the further improvements that will result in increased
consumption of grapes.
GRAPES 633
in the seventeenth century, were with the vinifera or European grape.
In 1619-21 the London Co., actively urging the culture of the vinifera
grape as a source of revenue, brought French vine workers and
collections of the best vinifera grape varieties of France to the settle-
ments in Virginia. The Colonial Assembly was also active at the
same time in encouraging and even ordering the care and cultivation
of the vine. Similar attempts were made in the various colonies from
New England to Georgia from 1619 to the beginning of the Kevolu-
tionary War.
Much has been written concerning these early attempts at growing
vinifera grapes in eastern United States. The reports can be briefly
summarized. The first year or two the vines gave considerable
promise, then disease and insects appeared, resulting in dead vines
and finally an abandoned vineyard. From present experience it
would appear that lack of resistance to cold, insects, and disease in
the northern regions, and susceptibility to disease and insect injury
in the southern regions, were the factors responsible for the general
failure of vinifera grape culture in eastern United States.
While failures were being recorded with vinifera grapes along the
Atlantic coast, a start in their culture was being made on the Pacific
slope in California. The Mission Fathers, going northward from
Mexico, established the San Diego Mission in 1769. They brought
grape material with them to plant at the various missions established
from San Diego to Sonoma. The first plantings made were of a
variety that became known as the Mission and represents earliest
successful culture of vinifera grapes in the United States. Very little
further development took place in California until after 1850. An
essay by Col. Agostin Haraszthy on grape growing and wine making,
published in 1858 and given wide circulation by the California State
Agricultural Society, so stimulated viticulture in the State that
20,000,000 vines had been planted by 1862. Cuttings and rooted
vines, including many of the better known varieties then grown in
Europe, were introduced into California and distributed to growers.
During the following years commercial grape growing, based entirely
on vinifera grapes, developed rapidly. Production increased from
11,000 tons in 1869 to 360,000 in 1899,'l,827,000in 1929, and 2,065,000
tons in 1935. Vinifera grape culture has also spread to other Western
and Southwestern States. In favorable locations in Idaho, Washing-
ton, Oregon, Nevada, Arizona, Utah, New Mexico, and Texas,
vinifera grapes prove profitable for local sale and, in special southern
locations, for early commercial shipments.
Development and Early Improvement of
American Native Grapes
After many failures with varieties of Vitis vinifera in the East, the
native species were finally considered to be the best basis for an
eastern grape industry.
Out of a planting of vinifera grapes made by the Kentucky Vineyard
Society shortly after 1802, near the present site of Vevay, Ind.,
several varieties resisted unfavorable conditions better than others.
One of these was called the Cape grape by John James Dufour II.
This grape was later supposed to be identical with Alexander, a native
138904°— 37 41 ++
634
YEARBOOK, 1937
American vine, which had been planted in some way among the
vinifera varieties. Later, from 1806 on, this native grape became
generally distributed and was grown with apparent success. Grape
authorities later considered the Alexander an offshoot of Vitis labrusca
L., with a possibility of some vinifera species in its parentage. It
probably originated along the banks of the Schuylkill in Pennsylvania,
and its history antedates the Revolutionary war.
The next incentive to native grape growing came with the intro-
duction of the Catawba variety. Its origin is uncertain. There is
evidence that it originated in North Carolina. In 1819 John Adlum
(1759-1836) obtained cuttings of the Catawba from a cultivated vine
in Maryland for extensive nursery propagation in the District of
Columbia. The cuttings of the variety were widely distributed by
Adlum and some were sent to Nicholas Longworth (1783-1863) in
Ohio, who became greatly impressed with it. During the period from
1825 to 1850 this variety, as well as Isabella and others less well-
known, was planted in widely separated parts of the Eastern States.
These two varieties were predominant until the introduction of the
Concord, which originated from a chance seedling grown by Ephraim
Wales Bull (1805-95), of Concord, Mass. The seed was planted in
1843 and produced fruit in 1849. The grape was named Concord and
introduced in the spring of 1854. The Concord grew rapidly in
popularity and its culture had spread to Missouri by 1855, 1 year
after its introduction.
The improved varieties of native grapes introduced between 1800
and 1850 were principally chance seedlings or selections from wild
native species. Since 1850 many men have been interested in grape
breeding for the improvement of our native species.
Native species of Vitis are found in all parts of the United States.
The fruit of many of them is of little direct value, but even the species
producing poor fruit may have characters of value for hybridization
and plant breeding. Some have been the source of our cultural
varieties, while others are very valuable as stocks resistant to phyl-
loxera and the root knot nematode. Table 1 indicates the main
grape species that have been used in breeding work.
Table 1. — Grape species jmssessing special breeding qualities
Character of vine
Resistance to—
Species, common name,
and natural range
1
d
S3
aj
Qualities for breeding
Vitis aestivalis Miehx.;
summer grape. New
England to Georgia
and westward to the
Mississippi River.
V. aestivalis var. bourqui-
niana Bailey (V. bour-
quiniana Muns.); Bour-
quin grape. Origin
doubtful; adapted to
Southeastern States.
Vigorous, climbing;
leaves large, 20 em,
3- to 5-lobed.
Vigorous, climbing;
leaves large, 3- to 5-
lobed.
14
VQ
a
F
P
o
o
Resistance to fungus
diseases; high sugar
percentage; suitable
wine properties; pos-
sible table use if crossed
with large-berried va-
rieties.
Vigor; disease resistance;
productiveness; col-
ored juice.
GRAPES 635
T.4BT.E 1. — Grape species possessing special breeding qualities — Continued
Species, common name,
and natural range
V. berlandicri Planch.;
Spanish grape, winter
grapo. Texas and
northern Mexico.
V. candicans Engelm.;
mustang grape. Mainly
Texas, parts of Arkan-
sas, Oklahoma, Louisi-
ana, and Mexico.
V. chavipini Planch.;
Champin grape. Main-
ly Texas.
V. cordifolia Lam.; frost,
grape. Wide range,
from Great Lakes to
Florida.
V. labrusca L.; fox grape.
New England to north-
ern Georgia, westward
to Indiana, and border-
ing the Ohio River.
V. Unsecomii Buckl.;
pinewoods grape, post-
oak grape. Texas,
parts or Louisiana,
Oklahoma, Arkansas,
and Missouri.
V. longli Prince; Longs
grape, bush grape.
Parts of Arkansas,
Oklahoma, Texas, New
Mexico, and southeast-
ern Colorado.
V. monticola Buckl.;
sweet mountain grape.
Texas.
V. rolundifolia Michx. ;
muscadine grape. Po-
tomac liiver to Florida
and west to eastern
Texas.
V. rupestris Scheole; sand
grape. Southern Mis-
souri and Illinois, Ken-
tucky, Tennessee,
Oklahoma, and eastern
and central Texas to
the Bio Grande.
V. vulpina L.; riverbank
grape. Canada to Tex-
as and west to Great
Salt Lake; wide range.
V. vinifera L.; European
grape, wine grape. In-
troduced species.
Character of vine
Medium vigor, slender;
leaves medium, 10 cm,
3-to 5-lobed.
Very vigorous, high
climbing; leaves me-
dium, nonlobed to 3-
lobed.
Very vigorous, climbing;
leaves medium, 10-12
cm, nonlobed to 3-
lobed.
Vigorous, climbing;
leaves medium, 10 cm.
Medium vigor, climb-
ing; leaves large, non-
lobed to slightly lobed .
Vigorous, bushy to
climbing; leaves very
large, 3- to 5-lobed.
Very vigorous, bushy to
climbing; leaves large,
3- to slightly 5-lobed.
Medium vigor, slender,
climbing; leaves small,
nonlobed to slightly
3-lobcd.
Vigorous, slender, climb-
ing; leaves small, not.
lobed.
Very vigorous, bushy,
rarely climbing; leaves
small, mostly non-
lobed.
Vigorous, slender, rnod-
erately climbing;
leaves large, mostly
nonlobed, to slightly
3-lobed.
Medium to strong vigor,
bushy to climbing;
leaves mostly 3-to 5-
lobed, occasionally 7-
lobed.
Resistance to-
20
19
VG
VG
VG
VG
VG
Qualities for breeding
Rootstock resistance *.o
phylloxera; ability to
grow on strong, limy
soils.
Vigor for rootstock; eas-
ily hybridized; adapted
to black limestone
lands; large-berried
fruit for wild vine.
Vigor for rootstock;
healthy foliage; wide
adaptability; large-
berried fruit.
Vigor; phylloxera resist-
ance; wide natural
range.
Cold resistance; large-
berried fruit; strong
distinctive flavor.
Vigor; disease resist-
ance; large clusters and
berries; strong flavor.
Vigor; phylloxera resist-
ance; easy rooting of
cuttings; vinous flavor.
G Phylloxera resistance;
health of foliage; fruit
medium to small.
Disease-resistant vine
and fruit; special fruit,
flavor.
Phylloxera resistance;
easy propagation; vig-
orous.
Phylloxera resistance;
cold resistance; easy
propagation.
Productiveness; high
quality; easy propaga-
tion; some seedlcssncss.
> Eatings under phylloxera resistance are from 1 indicating greatest susceptibility to 20 indicating almost
complete resistance.
! Symbols for resistance to cold, heat, wet soil, and drought are: VG=very good. G=good. F=fair.
One of the native species used extensively for breeding is Vitis
labrusca, the fox grape. From chance seedlings of this species came
Catawba and Concord, though they may also possibly have some
636
YEARBOOK, 193 7
V. vinifera in their parentage. Through early hybridization work a
number of popular varieties were obtained from V. labrusca crossed
with V. vinifera. One of the earliest grape breeders in this country
to utilize this cross was Edward Staniford Rogers (1826-99), of Mas-
sachusetts (fig. 1). Although engaged primarily in the shipping
business with his father, he became interested in horticulture and
conducted his experiments in grape hybridization in a garden on a
city lot back of his home. In originating the group known as Rogers
hybrids he used a large-fruited red
labrusca known as Carter and fer-
tilized the blossoms with pollen
of two vinifera varieties, Black
Hamburg and White Chasselas.
From these crosses, made in 1851,
heobtained about 150 seeds, which,
eventually produced 45 fruiting
vines of high quality. These
came into bearing between 1856
and 1858 and were numbered from
1 to 45 by Rogers. They were
widely distributed, and some were
finally named. Rogers continued
his work and recrossed varieties
already produced, but none of the
later seedlings was promising
^k. , enough to be introduced. This
early work of Rogers indicated
the value of V. vinyferam hybrid-
izing to improve the quality of
the native fruit. The Agawam
variety is one of liis main contri-
butions that is still grown.
Contemporary with Rogers
were many other men who introduced hybrid varieties of their own
breeding. Only a few of these can be mentioned here.
Andrew Jackson Caywood (1819-89), a nurseryman and fruit
grower, became interested in grape breeding in New York. Little
record of his methods remains. He differed from other grape breeders
of his time, however, in concentrating on second-generation hybrids.
The Dutchess represents one of his most important named varieties.
Charles Arnold (1818-83), of Canada, produced many seedlings.
Since he lived near the northern limits of grape culture, he was
interested mainly in producing cold hardiness in seedlings of high
quality. His crosses were mainly a combination of Vitis labrusca,
V. vulpina (the riverbank grape), and V. vinifera. His productions
proved hardy under severe climatic conditions but were more or less
susceptible to disease. Canada and Othello are two of his named
varieties.
George W. Campbell (1817-98) conducted his grape-breeding work
in Ohio and raised many seedlings. He used varieties mainly of
Vitis labrusca and V. vinifera and to some extent V. aestivalis var.
Figure 1. — Edward Staniford Rogers, of
Massachusetts, a pioneer iu grape hybrid-
ization.
GRAPES
637
bourquiniana (Munson) Bailey. Campbell Early represents his main
contribution to present-day viticulture.
Louis Suelter, of Carver, Minn., carried on most of his hybridizing
work between 1870 and 1884. Previous to this time he had grown
many seedlings of the wild grape, Vitis vulpina. One of these seedlings
appeared to blossom earlier and develop fruit color earlier than others.
By crossing this with Concord as the pollen parent, four seedlings were
produced and named Beta, Dakota, Monitor, and Suelter. These
are reported to be hardy for the
more northern and northwestern
parts of the country, and they
illustrate the use of V. vulpina in
obtaining cold-resistant varieties.
James H.Ricketts (1818-1915),
who conducted a bookbinding
business in Newburgh, N. Y.,
became interested in grape im-
provement, and one of his first
productions was Raritan. In
order to utilize vinifera varieties
to cross with native grapes he
constructed a glasshouse for
their culture. While his seed-
lings were not very vigorous, be-
cause of their large proportion of
vinifera parentage, they were
characterized by high quality
and large cluster and berry.
His crosses were mostly Vitis
labrusca and V. vinifera. Some
however, were complex hybrids,
containing in addition either V.
aestivalis (the summer grape) X
V. aestivalis var. bourquiniana
or V. vulpina parentage. Some
of his named varieties include
Downing, Empire State, and
Jefferson.
Thomas Volney Munson (1843-1915, fig. 2) conducted most of his
breeding work with grapes at Denison, Texas. The region in which
he lived is rich in native species. Munson gave much of his time to
the botanical study of grape species as well as to breeding and cultivat-
ing new varieties. In 1909 he published a summary of his extensive
work with grape species, breeding, and the testing of grape varieties
(fj).2 His work was largely instrumental in producing grape varieties
of the bunch type suitable for southern conditions, where most of
our varieties of northern parentage fail. Of particular interest and
special value was his use of the native species Vitis linsecomii, the
pinewoods grape, in the origination of hybrid varieties. By combining
and selecting the vigorous, healthy native species Munson was able to
originate fruiting varieties that are productive, vigorous, and better in
'Italic numbers in parentheses refer to Selected References on Grape Breeding, p. 655.
figure 2. — Thomas Volney Munson, of
Texas, who did notable work in the botan-
ical study and hybridizing of grapes. He
originated and introduced many superior
hybrid varieties, including varieties of the
bunch type especially suitable for southern
conditions.
638
YEARBOOK, 1937
fruiting qualities than, the parental types. More hybrid grape
varieties have been originated and introduced through his efforts
than by any other agency in the United States.
Other grape breeders who have contributed some of our better
known varieties include Joseph Backman, Hermann Jaeger, Jacob
Moore, and Jacob Rommel.
Table 2 gives the parentage and origin, so far as they are known,
of a number of the more important native American grape varieties.
Some of the varieties that originated as chance seedlings, including
Catawba, Concord, and Delaware, are among the most important
commercial varieties at the present time. However, when varieties
were needed for a specific purpose, such as hardiness, insect resistance,
or improved quality, controlled crossing became necessary. The
better known varieties are marked with an asterisk, and these can
usually be obtained from some of the many commercial nurseries.
Others are included as a partial list of varieties available for breeding
purposes in State or Federal experimental plantings.
Table 2. — Parentage and origin of American native grape varieties
[An asterisk (*) denotes the better known varieties.]
Variety
Color
Red....
...do...
Black..
Red....
8 [aniens
Species parentage <
Originated or intro-
duced by —
Dale
Slate or country
of origin
Uprlght.
... do
...do
E. S. Rogers
Joseph Hart
J. H. Ricketts
Joseph Backman
E. S. Rogers
T. V. Munson
A. F. Wylie ... .
1855
1893
187'J
1898
1855
1886
1871
1881
1872
1883
1901
1892
1800
1892
1823
1893
1870
"l835~
1880
1885
184(1
1857
18«5
1850
1881
1881
1870
1884
1805
1855
1808
1879
1902
1803
1874
1847
1915
Arkansas
Lab
Vulp., Lab
Lab., Vin., Bourq.
Lab., Vin___
Arkansas.
Black..
...do...
Red. -
Black. ..
Red—
...do...
...do...
Black..
... do...
..-do...
Red-
Black..
...do...
White-
Black..
White-
Black..
...do...
...do...
White-
Black..
...do...
Red-
White
Red-
Black
Red—
White-
Black..
Red ...
White..
...do...
Black..
...do.-
Reflex..
Upright.
—do
...do
Reflex. .
Upright.
...do
...do.-.j
...do
...do
___ dc>-__.
...do
...do
...do
...do
Reflex.. .
Upright.
... do— -
Reflex..
Upright.
...do
...do.-..
...do....
do....
_._do
...do....
...do
—do
...do
—do
...do
...do
Reflex..
Upright-
Beacon*
Line, Lab.
Vulp.,Lab.,Bourq.
Vulp., Lab
Lab:, Vin
Texas.
Beta*
Louis Suelter. .
Jacob Moore..
T. V. Munson _
J. T. Lovett--
O. W. Campbell....
Charles Arnold ...
T. V. Munson _
John Adlum
T. V. Munson
Brilliant*
Caco* .
Lab., Vin., Bourq.
Lab., Vin
Texas.
New Jersey.
Ohio.
Canada.
Texas.
Campbell Early*.
Canada
Carman*
do
Vulp., Lab., Vin..
Line, Lab., Vin.,
Bourq.
Lab., Via
Champanel
Champ., Lab
Lab
luinbia.
Texas.
Charles A. Green
do
Vulp., Lab
Lab...
F. W. Loudon
L. B. Langwell. ..
David Bundy
J. S. McKinley
Ephraim W. Bull...
F. F. Marceron. ...
S. W. Underhill
W. M. Prinee... ...
Louis Suelter..
A. Thompson
Jacob Moore .. ...
Diana Crehore _
J. H. Ricketts
Wisconsin.
Ohio.
Columbian Im-
perial.
Lab., Vulp..
Lab...
Do.
Pennsylvania.
Lab., Via., Bourq.
A est., Lab ..
Vulp., Lab
Lab., Vin., Bourq.
Cynthiana*
Dakota
Delaware*
Arkansas.
Minnesota.
Ohio.
do
do
Lab
Lab., Vin. .Bourq.,
Aest.
Lab
Line, Lab., Vin__
Vulp., Lab., Vin..
Lab,, Vulp., Vin..
Lab., Vin., Aest.-
Lnb
Downing
New York.
Dutchess*
Eaton _ .
Ellen Scott*
Elvira*
A. J. Caywood
M. C. Eaton _
T. V. Munson
Jacob Rommel.
J. H. Ricketts
Now York,
New Hampshire.
Texas.
Empire State
New York.
Do.
Fredonia*
N. Y. Agr. Expt.
Sta.
Do.
1 Abbreviations are used for species as follows: Aest. for Vitis aestivalis; Bourq. for I", aestivalis var. dour.
quiniaim; Champ, for V*. champini; Cin. for V. cinerea; Lab. for V. tabrusca; Line, for V. linstcomii; Rup. for
V. rupestris; Vin. for V. vinifera; Vulp. for V. eulpina.
GRAPES 639
Tabt.e 2. — Parentage and origin of American native grape varieties — Continued
Variety
Color
Stamens
Species parentage
Originated or intro-
duced by —
Date
State or country
of origin
Goethe
Red—
White-
...do...
...do...
do...
Black..
Eed....
Black..
Red-
Black
...do...
Reflex..
Upright.
...do
—do
Reflex- .
Upright.
... do
Reflex..
TJpright.
...do
E. S. Rogers
N. Y. Agr. Expt.
Sta.
T. V. Munson
1855
1916
IS94
3887
1881
1849
Massachusetts.
Now York.
Golden Muscat.
Governor Eoss..
Lab., Vin
Green Earlj'
Lab _
Grein Golden
Hartford
Vulp., Lab—
Lab., Vin
Nicholas Grein. ...
P. W. Steel
Missouri.
Connecticut.
Herberaont*. . .
Herbert ..
Lab., Vin
E. S. Eogers
C.W.Grant
1855
1855
181(3
1840
1888
1878
Massachusetts.
Iona*
do
Isabella*
do_.
1)0.
Ives*.. . ...
do
...do
...do
do
Reflex...
Upright.
—do
...do
...do
...do....
do
...do
Lab.,Acst.-
Jefferson
Bed—
White
Black
Red—
... do...
J. H. RickeUs
do _.
New York.
Do.
Lady Washing-
ton.
Lenoir*
do
Lab., Vin
E. S. Rogers _
M. Theard
1855
18S0
1890
18«5
1899
1864
1870
1871
1886
1872
1902
1873
1908
1883
1830
1903
1870
1880
1850
1912
1885
1855
1867
1921
1883
1897
1874
1922
Massachusetts.
Louisiana
Lucile*
... do—
... do—
Black..
White-
Black
...do...
Lab
J. A. Putman
L. C. Chisholm
T. V. Munson.-
S. Miller
Lutie
do.
Line, Rup., Lab.,
Vin., Bourq.
Lab., Vin. (?)
Vin., Lab
Tennessee.
Texas.
Martha
Mills _
W.H.Mills
Canada.
Massachusetts.
Texas.
New York.
Texas.
Illinois.
New York.
Massachusetts.
Do
Moore Early*.. .
Lab—
Muench*
Niagara* .
...do...-- .do
White dn_ _
Line, Bourq
Lab., Vin
T. V. Munson-
Hoagand Clark
T. V. Munson
Otto Wcssenzicher. -
N.Y. Agr. Expt. Sta
M. B. White
Nitodel.
Black..
White
—do-
Red.—
—do...
Black..
White. .
...do—
Eed
White
... do...
...do...
Eed—
Black..
...do...
...do...
Red....
...do...
Black..
White-
Black..
...do...
Red-
...do
do
—do
—do
...do
...do
—do
...do
—do
do
...do—.
...do
Reflex...
Upright.
—do
—do-
do—.
—do
...do
...do
—do
—do
Reflex
Cin., Lab., Vin.,
Bourq.
Vulp., Lab
Lab., Vin., Aest..
Ontario *.
Oriental
Perkins.
do
do
Pierce* __ ... .
Pocklington .
John Pocklington
N. Y. Agr. Expt. Sta.
A.J. Caywood
Portland*...
Poughkecpsie
Eebecca _.
do
Lab., Vin., Bourq.
Do.
Do.
Do.
Do.
Texas.
Massachusetts.
New York.
Do
Eipley
Eommel
Salem
Lab., Vin., Aest—
Vulp., Lab., Vin..
Lab., Vin
N.Y. Agr. Expt. Sta.
T. V. Munson.
E. S. Rogers
J. H. Ricketts
N.Y. Agr. Expt. Sta.
Louis Suelter
Secretary
Sheridan _
Vulp., Lab., Vin..
Lab., Vin...
Snelter
Sunrise.. ..
Vulp., Lab
Lab., Vin., Bourq.
Lab
Minnesota.
Vergennes*
W. C. Green.
N.Y. Agr. Expt. Sta.
J. A. Clough (?)
Westfield...
Winchell*
Lab., Vin
Lab., Vin., Aest— .
Aest., Line, Rup.
Lab._ _.
New York.
Wine King.
Worden* .
T. V. Munson
1898
1863
1870
Texas.
Wyoming
do
S. J. Parker
Do.
TECHNIQUE OF BREEDING
Structure of Grape Blossoms
To understand the technique of breeding new grape varieties, some
knowledge of the floral parts (fig. 3) is necessary. The blossoms of
Vitis are arranged in a pyramidal, loosely branched cluster known as a
panicle. In the wild state some vines may bear only male or stami-
nate flowers, while others bear perfect or hermaphrodite flowers that
have both stamens and pistils. American native species bear male
flowers and hermaphrodite flowers on separate vines, while most
European vines of Vitis vinijfera bear only hermaphrodite flowers.
The male flowers (fig. 3, A) differ from the hermaphrodite flowers in
bearing well-developed stamens and only an incompletely developed
pistil, which has no style or stigma and only a very small ovary, the
ovules of which cannot be fertilized. The pollen grains of the male
640
YEARBOOK, 193 7
Figure 3. — Grape flower parts. A, Male flower. B,
Flower with reflex stamens. C, Flower with upright
stamens: a, Filament; b, anther; c, ovary; d, style; e,
stigma; /, nectar gland; g, pedicel.
flowers will germinate and can fertilize flowers that have a normally
developed pistil.
The hermaphrodite blossoms range from flowers having reflexed,
very poorly developed stamens (fig. 3, B) to perfect flowers with upright
stamens (fig. 3, C). Varieties with reflex stamens usually do not set
fruit, or set only very
loose clusters, unless
they are cross-pollinat-
ed, either naturally or
artificially. Each indi-
vidual perfect flower
normally bears five
stamens although the
number may vary on
the same flower cluster
from four to eight. The
stamen consists of the
filament tipped by the
anther containing a
pair of pollen sacs. The
stamens surround the
fruit-producing part of the flower known as the pistil, which is made
up of the stigma, a slender-necked style, and an enlarged ovary. The
ovary contains the ovules which develop into seeds after fertilization
has taken place.
Previous to opening, these flower parts are enclosed in a cap-shaped
united corolla (fig. 4, A). At the time of blossoming, the corolla is
shed by becoming loosened at the
base and coming off like a cap (fig.
4, jB). When the flowers are in full
bloom, each pollen sac of the anthers
splits and sheds the pollen, which
is in the form of small, ellipsoid,
yellow grains. When moistened the
grains take on a globular form. If
examined microscopically, it can be
noted that the pollen grain is en-
closed in a cell wall with three thin-
walled bands extending around the
grain from pole to pole. In the
middle of each of these bands is
located a germinal pore through which the pollen tube will sub-
sequently develop.
The pollen grains are deposited on the stigma through natural or
artificial means. If the stigma is receptive and the pollen grain viable,
the pollen germinates and the pollen tube grows through the style,
reaches the ovary, and enters an ovule through a small passage be-
tween its outer and inner coverings known as the micropyle. Fer-
tilization then takes place by fusion of a sperm nucleus from the
pollen tube with the egg nucleus in the ovule. The fertilized ovules
become the grape seeds, and the ovary develops into the fruit or
grape berry.
Figure 4. — A, Grape flower bud. B,
Flower bud partly opened; a, corolla or
cap. C, Emasculated flower.
GRAPES 641
Method of Hybridizing
The steps used in the actual hybridizing of grapes by various workers
are more or less similar. After selection of the parent varieties, the
flower clusters of the male or pollen parent are enclosed on the vine
in sacks of paper, cellophane, or other material before any of the
individual flowers have opened. This prevents contamination of the
desired pollen by the pollen of other nearby varieties. As the blos-
soms open, the pollen remains within the sack and can be carried
directly to the variety to be pollinated or gathered into a suitable
container for future use.
The anthers are removed from flowers of the female parent before
any pollen has been shed, and the emasculated cluster is enclosed in
a bag to prevent the entrance of foreign pollen. At the time of polli-
nation, the pollen from the selected male parent is brushed over the
stigmas of the emasculated seed parent. When the fruit is ripe, the
seeds are collected, washed, cleaned, and stored for future planting.
Time can be saved by germinating the seeds in a greenhouse.
The young seedlings are usually transplanted to pots, cans, or a
coldframe for growing one season before they are planted in the
field for fruiting tests. The seedlings need some protection the first
summer, varying with the climatic conditions under which they are
grown. For field trial they are usually planted closer than in com-
mercial vineyards, mainly to conserve space. From reports received,
the distances vary from 6 inches to 4 feet in the row, with rows 5 to 12
feet apart. Fruiting may take from 2% to 4K years after the seedlings
were set in vineyard form, or from 3% to 5}i years from the time the
seed wa3 planted.
Recently a procedure that hastens the fruiting of grape seedlings
has been followed at the United States Experiment Vineyard, Fresno,
Calif. Grape seeds from controlled crosses in breeding work are
planted in flats and started under greenhouse conditions about
February 1. The seedlings are transplanted to 1 -gallon cans after
three or four true leaves are formed. During May and early June of
the same season these seedlings attain a growth of from 12 to 16
inches. At this time three or four buds from the basal part of the
seedling shoot can be obtained which are suitable for T budding.
These seedling buds are T-budded into vigorous shoots of rootstocks
or of bearing vines that are growing in vineyard form. With special
care and training the seedling buds can be forced into growth. By
the end of the first growing season, shoots from 6 to 12 feet long can
be developed. At pruning time a cane 3 to 4 feet long can be left for
next season's fruiting wood. At the Fresno station ripe fruit has been
picked in August, 18 months from the time the seeds were planted in
flats. This method saves at least 2 or 3 years compared with the usual
method of fruiting grape seedlings. While it may not serve as a test
of the commercial merits of a seedling, it does serve to determine
many qualities such as color, shape, size, and flavor of the fruit. As
with all breeding work, selection of desirable seedlings is necessary.
A number of vines of each seedling must be grown and observations
made of its commercial possibilities under various soil and climatic
conditions before it can be introduced for commercial culture.
642 YEARBOOK, 1937
PRESENT GRAPE -BREEDING WORK IN THE
UNITED STATES
Ik recent years hybridization of grape varieties and species has
been actively carried on at Federal and State experiment stations.
Most of the expansion has taken place since 1900, although a few of
the State stations were engaged in grape breeding previous to that
time. The most active interest has been evidenced since 1920. A
recent survey indicates that in addition to the grape-breeding program
of the Department the following State stations are conducting grape-
breeding work: California, Georgia, Maryland, Minnesota, Missouri,
New York, South Dakota, Texas, and Virginia.
The principal objectives have been improvement in fruit quality,
productivity, disease resistance, and adaptability to soil and climatic
conditions. The work is being carried on with three distinct types that
are of commercial importance in the United States — the American
native bunch grapes, the muscadine grapes, and the European or
Old World grapes. ,T _, „
Native Bunch Grapes
The native bunch grapes have been developed from various native
species, in many cases with the infusion of the European grape
through natural or controlled hybridization. The species from
which the varieties of this group have been derived rank in importance
in the following order: Vitis labrusca, V. vinvfera, V. aestivalis, V.
linsecomii, V. vulpina, V. aestivalis var. bourquiniana, V. charnpini,
V. rupestris, V. cinerea. This group, represented commercially by
such varieties as Beacon, Catawba, Concord, Cynthiana, Delaware,
Iona, Lenoir, Niagara (fig. 5), and others of lesser importance, is
grown, at least for home consumption, in every State in the Union.
Commercial production is principally in the North Atlantic States,
the Great Lakes region, the Central States, and to a lesser extent in
the South and in the Pacific Northwest. They are used for table,
local markets, shipment for some distance, unfermented juice, and
wine. The vines of this type are characterized by medium to vigorous
growth; the leaves are medium to large, three- to five-lobed or entire;
the tendrills are forked; and the fruit clusters are small to above
medium in size. The individual berries of different varieties vary in
outline from globular to ovoid. The skin separates easily from the
pulp, while the seeds are firmly retained in the pulp. The varieties
that have V. labrusca, or fox grape, parentage are characterized by
what is called a foxy flavor, which is very important in the manu-
facture of unfermented juice.
The trend of grape breeding with the native bunch grapes has been
to improve quality by crossing with varieties of Vitis vinvfera. This
has been successfully done by the New York (State) Agricultural
Experiment Station, which has introduced 21 named seedlings for
commercial trial. The northern species, V. labrusca and V. vulpina,
have been utilized by the Minnesota and South Dakota Stations to
develop varieties with cold hardiness for the northern regions. Size
of berries has been increased by the use of V. labrusca. Cold hardiness
and adaptability have been developed by the use of V. vulpina.
Thirty-two named seedlings have been introduced by the South
GRAPES
643
Figure 5. — The Niagara, one of the high-quality grape varieties developed from
American species.
644
YEARBOOK, 1937
Dakota Station. The stations of Maryland, Missouri Texas, and
Virginia, and the United States Department of Agriculture atBelts-
viJle, Md., are conducting grape-breeding work to improve the quality
and adaptability of the native bunch-grape types by crossing varieties
containing labrusca and vinifera parentage with varieties developed
from more southern species, such as V. aestivalis, V. aestivalis var.
bourquiniana, V. champini, V. linsecbmii, and V. rupestris.
Desirable Objectives in Breeding American Bunch Grapes
In the United States the desirable objectives in breeding the
American bunch grapes vary with the regions in which they are
grown, and regional
needs must be studied
separately. Three main
regions are involved:
(1) The North Atlantic
States, the grape-grow-
ing areas along the
Great Lakes, and the
North Central States;
(2) the Southern States ;
and (3) the northern
Great Plains.
In the first region it
would seem desirable,
in the case of table
grapes, to combine in-
creased production with
increased size of cluster
and berry. In quality,
the strong flavor of the
labrusca may be amel-
iorated by the addition
of the rich vinous flavor
of the vinifera. The
skin should be more edi-
ble and the flesh more
melting than is the case
with the Concord type
if these qualities can
at the same time be combined with improved shipping and handling
qualities. The sugar content could be increased and the acidity adjacent
to the seeds decreased. The seeds should separate readily from the pulp .
It may not be too much to hope that the seeds can at some future time
be entirely eliminated. In the case of varieties for unfermented
juice, increased productiveness, a more highly colored juice, and a
more melting pulp would seem desirable. Desirable improvement in
varieties for wine varies with the type of wine. In general, increased
sugar content, more juice production, and earlier maturity are desir-
able objectives. The development of a more vigorous, hardy,
disease-resistant, and insect-resistant root system would materially
aid the industry as a whole.
Figure 6. — A typical cluster of muscadine grapes,
Scuppernong variety.
GRAPES
645
In the second region, the Southern States, important consideration
should be given to resistance to disease and insect injury, principally
downy mildew {Plasmopara viticola (Berk, and Curt.) Berl . and DeToni ) ,
black rot (Guignardia bidwellii (Ell.) Viala and Ravaz), root rot, and
phylloxera injury. Improved size of berry and better quality would
seem desirable. Varieties adapted to the various soil and climatic con-
ditions would be of great assistance to the industry in this region.
In the third region, the northern Great Plains, cold hardiness must
of necessity be of primary importance. It would seem possible to
combine the cold hardiness of the more northern species with the
Figure 7. — Flower clusters of muscadine grapes. Upper three clusters, staininate
blossoms; lower three clusters, pistillate or fruit-bearing blossoms.
size and quality of some of the improved varieties. Some of the more
hardy yinifera varieties that mature in a short growing season may be
hybridized with the more hardy native species to promote both early
maturity and improved quality.
Muscadine Grapes
The muscadine grapes are especially adapted to the Southeastern
and Gulf States. Selections have been made from chance seedlings
and from the native wild vines of Vitis rotundifolia, the muscadine
grape. This type of grape is represented commercially by the
varieties Eden, James, Mish, Thomas, Scuppernong (fig. 6), and
646 YEARBOOK, 1937
others less prominent. They are used for table, local markets, juice,
and wine. The vines of this type are characterized by vigorous
growth, small, nonlobed leaves, simple tendrils, and smalT fruit
clusters, sometimes with only a few berries. The adherence of berry
to pedicel is generally poor. The individual berries are globular.
The sldn is mostly tough and leathery and separates readily from the
pulp. The seeds are large and firmly embedded in the pulp. The
strong musky flavor is very characteristic.
The present commercial varieties of muscadine grapes are not
self-fertile (fig. 7). In commercial plantings it is necessary to include
male vines to pollinate the fruiting varieties. Through crosses and
selections by the Department at Willard, N. C, a number of self-
fertile varieties have been produced. The breeding work at this
station has concentrated on the production of these self -fertile,
perfect-flowered types. Hybrids have also been obtained between
the muscadine grapes and the European and the American bunch-type
grapes. The Georgia Experiment Station has also been conducting
breeding work with muscadine grapes for improvement in vine and
fruit qualities. Eleven muscadine varieties having improved char-
acters have been introduced for commercial trial by the Georgia
Desirable Objectives in Breeding Muscadine Grapes
The muscadine grapes normally have a high resistance to disease
and insect injury, and these qualities should be retained. It is
desirable to combine quality and size of fruit with the perfect- or
hermaphrodite-flowered types. The bunch size might be increased
and adherence of the berry to the pedicel developed. The skin
might be made more tender and the sweetness and flavor ameliorated
by crossing with other grape species. The seeds of the muscadine
grapes are larger than those of any other native species, and the
development of varieties with smaller seeds would be a decided
improvement. „
r European or Vinifera Grapes
The European or Old World grape types have been developed from
the one species, Vitis vinifera. The vinifera grape industry in the
United States, representing approximately ^ 90 percent of the total
commercial grape production, is centered in California, with local
plantings in other Western States. The vines of this type are stocky
and vigorous to very vigorous in growth. The leaves are medium to
very large and usually characteristically lobed. The fruit clusters
vary widely with the variety, from very small to very large. The
individual berries range from small, as in the seedless currant type,
to very large in the table varieties. While the more typical shape of
the berries of this type is ovoid, there are globular and elongated forms.
The skin adheres to the pulp, whereas the seeds separate readily from
the pulp. Some varieties, such as the currant and seedless raisin
types, develop without seeds. The fruit is characterized by a rela-
tively high sugar content and a rich vinous flavor. There are types
suitable for table use, distant shipping, storage, raisins, juice, and
wine (fig. 8). Numerous varieties have been imported from foreign
sources for trial in the United States, and of course all of our present
commercial vinifera varieties are of foreign origin.
GRAPES
647
Figure 8. — Typical vinifera grape varieties: A, Flame Tokay, table type; B, Sultanina
(Thompson Seedless), seedless raisin type; C, Panariti, currant raisin type; D, Petit
Syrah, wine type.
648 YEARBOOK, 1937
The important table varieties are represented by Alexandria
(Muscat of Alexandria), Alphonse Lavalle (Ribier), Castiza (Red
Malaga), Emperor, Flame Tokay, Malaga, Ohanez, Olivette Blanche,
Olivette Noire, and Sultanina (Thompson Seedless). The chief raisin
varieties grown are Alexandria, Panariti (Zante currant type), Sul-
tana, and Sultanina. There are many varieties utilized for wine
manufacture. The white varieties used for wine include Alexandria,
Burger, Chasselas de Fontainebleau, Feher Zagos, Franken Riesling,
Gewurz Trammer (pink), Green Hungarian, Muscadelle du Bordelais,
Muscat de Frontignan, Palomino, Pedro Ximines, Sauvignon Blanc,
Sauvignon Vert, and Semillon. The black varieties include Alicante
Bouschet, Aramon, Barbera, Cabernet Sauvignon, Carignane, Cinsaut,
Grenache, Mataro, Mission, Mondeuse, Petit Syrah, Refosco, St.
Macaire, and Zinfandel.
The trend in vinifera grape breeding in the United States has been
to produce more seedless types and improved table, raisin, and wine
varieties. Breeding work is being conducted by the Department at
Fresno, Calif., and by the California Agricultural Experiment Station
at Davis.
At the United States Experiment Vineyard, Fresno, Calif., approxi-
mately 500 seedlings have fruited, and seedless-type seedlings have
been produced. Earlier maturity has been promoted by crossing
early-ripening varieties. Richness of flavor has been transmitted by
muscat-flavored varieties. Large-sized berries and a wide range of
berry forms have been obtained. Seedlings with red juice adaptable
to unfermented juice and to wine manufacture have been produced.
Selections have been made of the most promising types for further
production tests.
Desirable Objectives in Breeding Vinifera Grapes
In the United States the desirable objectives in breeding vinifera
grapes vary with the purpose for which the fruit is intended. The
type may be divided into table, raisin, and wine groups, although
some varieties may be used interchangeably.
The table group is made up of varieties used locally, shipped to
distant markets, and held in cold storage for later use. Since the
major portion of the table-grape crop must be shipped from Cali-
fornia to the distant eastern markets, firmness of fruit and adherence
of berry to pedicel are of primary importance. These qualities are
possessed by most of the present shipping varieties. The quality of
these table varieties might be improved by the infusion of some of the
aroma and flavor of the muscat-flavored grapes. Seedlessness in
table grapes has become an important factor. While some seedless
varieties are available at present, improvements are possible in size,
adherence to stem, quality, color, and extended season of maturity.
Improved early- and late-ripening grapes would have a distinct value
in prolonging the market season. A storage grape of fine eating
quality would be of great value. An assortment of black, red, and
white grapes ripening from early to late would supply a demand that
is not filled at the present time.
The raisin-grape group at the present time consists of currant-
type, seedless-type, and muscat-type varieties. A currant-type
GRAPES 649
variety with the addition of muscat flavor that would be productive
without the annual ringing or cutting of the bark, which is now neces-
sary, would be a decided improvement over present varieties. The
present seedless-type raisin varieties could well be increased in size
and improved in flavor. A large-sized, seedless, muscat-flavored
variety would be very valuable to the raisin industry. A seeded
muscat type that woxild set well-filled, uniform clusters would be a
valuable improvement.
In the wine group, many varieties are utilized to make the various
kinds of wine. To make certain wine types, the juice of several
varieties, often three or more, is blended. It would seem to be within
the realm of possibility to blend the varieties by breeding to produce
a single variety with all the requirements for a particular land of wine.
Varieties with improved flavors and juice of a more intense and lasting
color might be developed. At present all vinifora varieties must be
grafted on roots resistant to phylloxera. Some day, varieties resistant
to phylloxera, with fruit of desirable quality, may be developed so
that grafting will not be necessary. The legalized sale of wines has,
of course, furnished an incentive to produce a better product, and this
will ultimately result in a greater demand for improved varieties for
wine pxirposes.
EARLY IMPROVEMENT OF GRAPES IN EUROPE
As previously stated, the history of Vitis vinifera, the European
grape, begins in prehistoric times. During this long period, selection
was undoubtedly largely responsible for the numerous varieties con-
cerning the origin of which we have no definite information. Early
hybridization work with this species was started by Louis and Henry
Bouschet in 1828. Their crosses were made with the definite object
of combining the intense color of the Tinto with the high yield of
varieties in southern France. Their efforts resulted in the production
of three varieties, Alicante Bouschet, Petit Bouschet, and Grand Noir
de la Calmette, which are still of commercial importance.
In France, hybridization of native American species assumed very
great importance after phylloxera had made the grafting of vinifera
varieties on resistant roots necessary. Between 1860 and 1870,
diseased spots were noted in many French vineyards. The weakening
of the vines was found to be caused by an insect (Phylloxera vitifoliae
Fitch) living on the roots. Winged forms of the insect, which cause
the formation of galls on the leaves, were also found. The phylloxera
is indigenous to the eastern and central United States and probably
was carried to France before 1860 on rooted American vines imported
to resist damage then being caused in Europe by powdery mildew
(Uncinula necator (Schw.) Burr). Phylloxera spread rapidly over
France and the adjacent vine-growing countries. In order to save
the vinifera vineyard industry from complete destruction, it was
found necessary to graft the European varieties on native American
rootstocks, which were resistant to the phylloxera insects. The
United States thus furnished both the disease and the cure. Since
the American grape species varied in their adaptability to the soil
and climatic conditions of Europe, hybrids between American species
138904°— 37 42
650 YEARBOOK, 1937
and hybrids between European and native American grapes were
utilized for phylloxera-resistant rootstocks.
Some breeding work to combine American and European vines had
been started previous to 1876 by the School of Agriculture at Mont-
pellier, France. Foex, Millardet, Viala, Ravaz, de Gr asset, Ganzin,
Couderc, Castel, and Seibel practiced similar hybridizing work, wliich
resulted in producing many rootstocks resistant to phylloxera and
adapted to different soil types. Direct-producing varieties were also
sought that would combine the resistance of the American species with
the fruit qualities of Vitis vinifera. Many direct-producing varieties
were originated through breeding. While the efforts were most
successful in producing resistant rootstocks that are used today in the
vinifera regions of foreign countries as well as the United States, ideal
direct-producing fruit types were not obtained. A start was made,
however, which may eventually bring results.
Phylloxera infestations occurred early in the commercial vinifera
plantings in California. The only present method of control that has
general application is the use of resistant rootstocks on which the
vinifera grape varieties are grafted. These rootstocks are of American
species and hybrids of American species, though the actual develop-
ment of them occurred in Europe where phylloxera ravaged the vine-
yards before it became serious in California. Up to this time, the
vinifera grape industry in the United States has depended for stocks
on these species selections and hybrids made in Europe. The adapt-
ability of the stocks to the various soil and climatic conditions and
their suitability for the vinifera varieties in the United States have
been tested by Federal and State workers. Breeding work is now
under way for the production of improved stocks for the vinifera
regions of the United States.
PRESENT GRAPE -BREEDING WORK
IN OTHER COUNTRIES
Czechoslovakia
Investigations in grape breeding in Czechoslovakia are under the
direction of Albert Stummer in Nikolsburg and Dr. Franz Frimmel in
Brunn. This work, located at the extreme northern edge of com-
mercial grape growing in Europe, includes the testing of resistant
stocks, hybridization of varieties to secure wine and table grapes well
adapted to northern production, and related investigations. Crossing
and selfing of many varieties has been done.
France
French investigators, through selecting and breeding rootstocks
resistant to phylloxera and congenial to vinifera varieties, saved the
industry of Europe after phylloxera was introduced. A number of
privately supported experimental vineyards, as well as a few publicly
supported research stations, are still working on resistant understocks,
also on hybridizing American species with vinifera varieties to secure
varieties sufficiently resistant to grow on their own roots and be re-
sistant to downy mildew (Plasmopara) and that will produce fruit of
value. Work of this type is under way in the Cognac region.
GRAPES 651
Germany
Grape breeding is conducted at several points in Germany, as
follows:
Alzey Grape Experiment Station (Leader, Grape Inspector Scheu). —
Crosses are made with the objective of securing early-ripening and
vigorous, good-quality wine grapes and also a series of table-grape
varieties ripening from early until extremely late that are well adapted
to the Rhineland area. From 15,000 cross-bred seedlings, 450 selec-
tions are being tested.
Freiburg; Badisches Weinbauinstitute (Director, Dr. Muller). —
Breeding investigations are to secure varieties giving very high wine
quality. Crosses of Sylvaner X Eiilander have given exceptional wine
quality and are being tested on various rootstocks. Resistance of
varieties to downy mildew and the development of varieties having
dark-red juice are other objectives. Twenty-five selections producing
dark-red wine have been made.
Geisenheim a. Rh.; Versuchs- und Forschungsanstalt jur Wein-, Obst-
und Gartenbau (Director, Prof. Dr. Rudloff ; in charge of grape inves-
tigations, Dr. Birk). — The work includes attempts at improvement
of the varieties through clone selection; the breeding and testing of
phylloxera-resistant rootstocks having good adaptation and an affinity
to the important varieties and that are resistant to diseases; and the
breeding of early- and late-ripening, high-quality table grapes.
Muncheberg; Kaiser Wilhelm-Institutjur Zuchtungsjorsehung (Direc-
tor, Prof. Dr. Rudorf; in charge of grape investigations, Dr. Husfeld
and Dr. Scherz). — Investigations are primarily to develop disease-
resistant and insect-resistant rootstocks, vines, and varieties. Seed-
lings are grown by the hundreds of thousands and exposed to disease
infection. Fifty thousand seedlings resistant to Plasmopara have
been found. Their stock compatibility and value for wine remain to
be tested.
Weinsberg; Wurttembergische Anstalt jur Rebenziichtung und Reben-
pjropjung (Leader, Mr. Herold) . — The work consists primarily of the
testing of understocks against phylloxera and the development by
hybridization and testing of red-wine varieties.
Wiirzburg; Staatliche Hauptstelle jur Rebenziichtung (Leader, Dr.
Ziegler). — Breeding investigations include clone selection and hy-
bridization between grape varieties. Some 200 prospective varieties
from crosses between varieties are now under test. Breeding of root-
stocks resistant to Plasmopara and phylloxera, and showing good
affinity with varieties, has resulted in about 1,500 selections that
appear resistant and are receiving further tost. Development of
direct prodiicers that combine resistance to phylloxera and diseases
with good fruit and wine characteristics is also being attempted.
Italy
Grape-breeding experiments have been actively conducted at
various places in Italy. Special attention has been given to the hy-
bridizing of American vines for rootstocks. F. Paulsen, A. Ruggeri,
C. Grimaldi, and C. Montoneri, working principally in Sicily, have
produced hybrids of American vines for rootstocks. Some of the
652 YEARBOOK, 1937
more promising productions are Paulsen hybrids (Vitis berlandieri X
V. rupestris) Nos. 771, 775, 779, and 1103; {V. berlandieri X (V. ripa-
ria X V. rupestris)) No. 1120; (V. berlandieri X (Aramon X Rupestris
Ganzin)) No. 1045; (V. berlandieriX (Mourvedre X V. rupestris 1202))
No. 1323; Ruggeri hybrids (V. berlandieri X V. rupestris du Lot)
No. 140; (V. berlandieri X V. riparia) Nos. 225, 240, and 325. Other
hybrid rootstocks have been originated in Puglia by G. Ceccarelli
and V. Prosperi.
Breeding for better table-grape varieties has been conducted by
Alberto Pirovano, director of the Institute of Fruit Culture and
Electogenetics at Rome. Crosses and backcrosses have been made
with a number of yinifera varieties. Among the most interesting and
noteworthy seedlings produced are Primus, Termidoro, Delizia di
Vaprio, Italia, Aurora, Galvani, Perlona, Angelo Pirovano, Teresa
Pirovano, and Principessa di Piemonte.
V. Prosperi, director of the Royal Nursery of American Vines at
Velletri, has also obtained some interesting table-grape seedlings. Of
special note are No. 167 (Moscato de Terracina X Chasselas Vibert)
and No. 8 (Panse Precoce X Moscato Fior d'Aranico).
The Royal Experiment Station of Viticulture and Oenology of
Conegliano, founded in 1923, began hybridizing work with Vitis
vinifera. Particular attention has been given to the production of new
types of wine and table grapes with regard to their adaptability to the
natural conditions of northern Italy. The Work of this station was
planned by Director G. Dalmasso and L. Manzoni. Italian and French
varieties of V. vinijera have been used in the grape-breeding work.
Better types have been secured so far from crosses of Trebbiano X
Traminer, Prosecco X Cabernet Sauvignon, Trebbiano X Verdiso, and
Besgano X Moscato de Amburgo. More recently the Conegliano
station has started hybridization of V. vinijera with American vines,
and hybridizing American vines, for the production of new rootstocks
more adapted to conditions in the Province of Venezia.
Union of Soviet Socialist Republics
The following outline of the grape investigations in the Union of
Soviet Socialist Republics has been taken from Plant Breeding in the
Soviet Union, by N. I. Vavilov, published by the Imperial Bureaux of
Plant Genetics, Cambridge and Aberystwyth, 1933. Fourteen plant-
breeding centers, covering every section of the Soviet Union, con-
stitute regional headquarters for breeding work covering all agricul-
tural crops. These are all under the direction of the Institute of Plant
Industry, N. I. Vavilov, director. The grape program includes the
following:
(1) Immunity: (a) Phylloxera. Breeding resistant varieties by method of
cyclic crossing of Vitis vinifera with American species and obtaining generations
up to F2 and F3 (with study of characters of phylloxera), (b) Mildew. Breeding
resistant varieties by method of cyclic crossing of V. vinifera with American species
(obtaining generations up to F2 and F3, and study of resistance to mildew),
(c) Oidium. Breeding resistant forms by method of cyclic crossing of V. vinifera
with American species (obtaining generations up to F2 and F3, and study of resist-
ance to Oidium).
(2) Resistance to frost and cold. Breeding resistant varieties by means of
Vitis vinifera X V. amurensis with study of this character.
GRAPES 653
(3) Vegetative period. Breeding early and later varieties (in order to extend
their cultivation northward) by means of intercrossing of V. vinifera and also by
crossing with other Vitis species.
(4) Chemical characters. Breeding of dessert varieties with transportability,
varieties for wine and alcohol-free beverages (sugar and acid content) .
(5) Specific characters: (a) Preliminary work, on study of characters related
to transportability and storing; (b) study of seedless varieties in order to obtain
productive seedless strains; (c) study of character of rooting in Vitis.
(6) Problem of sex. Study of heredity of sex in order to obtain self-fertile
varieties.
(7) Self-sterility and self-fertility. Study to improve yield.
(8) Permanent modifications. Genetic study (yield of quantitative characters) .
(9) The origin of cultivated plants. Comparative genetics of wild Vitis species.
(10) Chimeras: (a) Study of chimeras in order to find agriculturally valuable
characters; (6) production of chimeras of practical value; (c) qualitative inequality
of ontogenetic system of individuals.
Vitis should be included in studies of inbreeding.
Phytopathology and entomology: Methods of inoculation of seedlings with
phylloxera, downy mildew, and Oidium. _ Testing of seedlings for resistance to
phylloxera under various ecological conditions.
Physiology Stimulation of seedlings and seeds to accelerated growth and fruit
bearing.
Australia
The Department of Agriculture, New South Wales, Australia, at its
Yanco Experiment Farm, started grape breeding in 1928, under the
direction of H. Wenholz, to produce a black table grape of high quality
and with the shipping quality of Ohanez. Breeding for disease re-
sistance and for the production of seedless raisin and table varieties
has been in progress.
ACHIEVEMENTS AND NEEDS
The major portion of the grape-breeding work has been to improve
quality. Quality is an elusive factor. In quality of fruit, native
American types are considered inferior to the vinifera types. The
quality of fruit has been improved where our native varieties have
been crossed with the best-quality varieties of Vitis vinifera. Improve-
ments in cluster and berry types have been made by combining differ-
ent native species. Grape rootstocks have been developed through
hybridization winch have suitable resistance to phylloxera and are
adapted to various soil types.
The results so far obtained indicate that grape improvements can
be obtained through hybridization. The field of grape breeding is
still relatively new. There is need for more information, especially
on the inheritance of desirable characters such as size, quality, secd-
lessness, cold hardiness, disease and insect resistance, and adaptability
to environment. Collections of species, native American varieties, and
European varieties are available as breeding material. Progress
has been made, but continued improvement is possible. Better qual-
ity, more attractive appearance, and a prolonged season will re-
sult in increased demand and consumption, to the ultimate profit
of the grape industry.
INHERITANCE IN GRAPES 3
Early grape breeding was carried on mainly to obtain desirable va-
rieties or stocks, and little attention was given to the study of inhorita-
s The following pages are written primarily for students and others professionally interested in breeding
or genetics.
654 YEARBOOK, 1937
ble qualities. As intensive breeding work has been in progress a rela-
tively short time, and the time necessary from seed to fruit in one
generation of grapes occupies ordinarily from Sji to 5% years, only
limited data are available on the transmission of inheritable qualities.
Genetic and cytological research projects at State and Federal institu-
tions are listed in the appendix material.
The somatic chromosome number of most vinifera grapes and most
American bunch-grape species is 38. Gigas forms of American and
vinifera varieties are tetraploids with 76 chromosomes in the somatic
tissues. Most American bunch-grape species will cross readily with
one another and with vinifera varieties, forming fully fertile hybrids.
The two muscadine species cross freely with each other, with fertile
hybrids resulting. The muscadines and vinifera varieties or American
bunch-grape types are crossed with some difficulty, and the Ft hybrids
of these crosses generally set but few if any fruits.
One important commercial consideration concerns the character of
grape flowers — whether the stamens are upright or reflex. At the
New York (State) Agricultural Experiment Station, crossing two
varieties with reflex stamens gave in the Fi a ratio of 1 reflex to 1
upright in the resultant progeny. Crossing upright stamens with
reflex stamens gave the same ratio, while crossing two varieties with
upright stamens gave 4.3 upright to 1 reflex in the Ft progeny. From
crosses of vinifera varieties with upright stamens at the United States
Experiment Vineyard, Fresno, Calif., the ratio of upright to reflex
stamens in the Fi seedlings was 5.4 to 1.
In color of fruit, white is a recessive character, and only white-
fruited progeny results when two white-fruited varieties are crossed.
Both red and black are dominant over white, and most of the red and
black varieties studied appear to be heterozygous for color.
The investigations of Hedrick and Anthony (5) at Geneva, N. Y.,
reported in 1915, relative to color, indicated that crosses of black-
fruited and white-fruited varieties gave in the Fi approximately 3
black-fruited seedlings to 1 white-fruited. Black-fruited and red-
fruited varieties segregated into these colors only when selfed or
crossed. At the United States Experiment Vineyard at Fresno, Calif.,
the segregation obtained in the first and later generations of crosses
among varieties with colored fruit has varied with the different parent
varieties used. It would appear that the majority of colored grapes
on which data are available are heterozygous for both red and black
color.
During recent years attention has been given to the origination of
more seedless varieties of grapes through breeding. A. B. Stout, of
the New York Botanical Garden, in cooperation with the New York
(State) Agricultural Experiment Station, has produced seedless or
near-seedless types by using the pollen from the present seedless
vinifera varieties to pollinate American-type varieties. At the United
States Experiment Vineyard, Fresno, Calif., crosses have been made
between the seedless vinifera varieties and many of the seed-bearing
vinifera varieties. Of the seedlings that have fruited to date, 12.4
percent have produced seedless-type fruit in the Fi generation. The
production of seedlessness in the Fi generation has proved the value
of seedless varieties as male parents to produce new seedless types.
GRAPES 655
While the inheritable factor for seedlessness has not been determined,
progress has been made in developing more seedless varieties for
breeding work, some of which may also be of commercial value.
SELECTED REFERENCES ON GRAPE BREEDING
(1) Alderman, W. H.
1936. ACCOMPLISHMENTS IX FRUIT BREEDING BY STATE AM) FEDERAL EX-
PERIMENT stations. Amer. Soc. Ilort. Sci. Proc. (1035) 33:
13-20.
(2) Bailey, L. H.
1934. THE SPECIES OF GRAPES PECULIAR TO \ORTH AMERICA. In lllS
Gcntcs Herbarium 3: 149-244, illus.
(3) Dearing, G.
1917. muscadine grape breeding . . . Jour. Heredity 8: 409-424,
illus.
(4) Hedrick, U. P.
1908. the grapes of new York. N. Y. Dcpt. Agr. Ann. Kept. 15, v. 3,
pt. 2, 564 pp., illus.
(5) and Anthony, R. D.
1915. INHERITANCE OF CERTAIN CHARACTERS OF GRAPES. N. Y. State
Agr. Expt. Sta. Tech. Bull. 45, 19 pp.
(6) Munson, T. V.
1909. FOUNDATIONS OF AMERICAN GRAPE CULTURE. 252 pp., illllS. New
York.
(7) Nebel, B. It.
1929. zur zytologie von malus und vitis. Gartcnbauwisseuscliaft 1:
[549]-592, illus.
(8) Snyder, E.
1935. BREEDING FOR SEEDLESS VINIFERA GRAPES. AniCT. SoC. Ilort. Sci.
Proc. (1934) 32: 381-383.
(9) Stuckey, H. P.
1919. WORK WITH VITIS ROT UNDI FOLIA, A SPECIES OF MUSCADINE GRAPES.
Ga. Expt, Sta. Bull. 133, pp. 60-74, illus.
(10) Wellington, R.
1931. THE VALUE OF THE EUROPEAN GRAPE IN BREEDING GRAPES FOR NEW
york state. Amer. Soc. Hort. Sci. Proc. (1930) 27: 416-421.
APPENDIX
Location of Present Grape Breeding in the United States and
Investigators Conducting the Work
United States Department of Agriculture, Bureau of Plant Industry, Division
of Fruit and Vegetable Crops and Diseases:
Beltsville, Md.: C. A. Magoon, I. W. Dix, J. R. Magness.
Fresno, Calif.: Elmer Snyder, F. N. Harmon.
Meridian, Miss.: N. A. Loomis.
Willard, N. C: C. T. Dearing.
State agricultural experiment stations:
California, Davis: H. P. Olmo.
Georgia, Experiment: H. P. Stuckey.
Maryland, College Park: A. L. Schrader, S. W. Wentworth.
Minnesota, University Farm, St. Paul: A. N. Wilcox.
Missouri, Mountain Grove: Paul H. Shepard.
New York:
Geneva: Richard Wellington and coworkers.
Frcdonia: F. E. Gladwin.
Now York Botanical Garden, Fordham Station, New York: A. B. Stout.
South Dakota, Brookings: N. E. Hansen.
Texas, College Station: S. H. Yarnell.
Virginia, Blaoksburg: F. W. HofMarm.
656
YEARBOOK, 1937
Summary of Present Grape Breeding in the United States
California
Main grape breeding work started in 1931 to produce new seedless varieties,
improve the quality of table varieties, and to study genetic factors. Crosses and
selfed varieties have yielded approximately 3,000 seedlings. The chromosome
number for Sultanina was found to be 38 and of the Gigas types to be 76. Breeding
material includes a large number of vinifera varieties and a collection of native
American species. Selfed seedlings are being grown of the following varieties:
Alexandria (Muscat of Alexandria), Alphonse Lavallce (Ribier4), Angulato,
Black Corinth, Chaouch, Chasselas Cioutat, Diamond Jubilee, Emperor, Flame
Tokay, Gros Colman, Hunisa X Muscat, Malaga, Malvasia Bianca, Molinera,
Muscatello Fino, and Ohanez.
Seedlings have been obtained from the following crosses: Alexandria X Black
Corinth, Alexandria X Sultana, Alexandria X Sultanina, Alexandria X Sultanina
Gigas, Alexandria X Sultanina Rosea, Alexandria X White Corinth, Alphonse La-
vallee X Monukka, Alphonse Lavallee X Sultana, Alphonse Lavallec X Sultanina,
Alphonse Lavallee X Sultanina Gigas, Augibi X Sultanina, Black Morocco X
Golden Muscat, Burgrave X Monukka, Burgrave X Sultanina, Chaouch X Alexan-
dria, Chaouch X Black Corinth, Chaouch X Monukka, Chaouch X Sultana, Cha-
ouch X Sultanina, Damas Rose X Monukka, Damas Rose X Sultanina, Damas
Rose X Sultanina Gigas, Dattier de Beyrouth X Monukka, Dattier de Beyrouth
X Sultanina, Diamond Jubilee X Monukka, Diamond Jubilee X Sultanina, Em-
peror X Monukka, Emperor X Sultanina, Flame Tokay X Black Corinth, Flame
Tokay X Monukka, Flame Tokay X Sultana, Flame Tokay X Sultanina, Flame
Tokay X Sultanina Rosea, Flame Tokay X White Corinth, Golden Muscat X
(Hunisa X Muscat) , Golden Muscat X Sultanina, Gros Colman X Monukka, Gros
Colman X Sultanina, Gros Colman X Sultanina Gigas, Gros Colman X Sultanina
Rosea, Henab X Monukka, Hunisa X Black Corinth, Hunisa X Golden Muscat,
Hunisa X Monukka, Hunisa X Sultanina, Hunisa X Sultanina Gigas, (Hunisa X
Muscat) X Golden Muscat, (Hunisa X Muscat) X Malvasia Bianca, (Hunisa X
Muscat) X Alexandria, Madeleine Angevine X Luglienga, Madresfield Court X
Monukka, Madresfield Court X Sultanina, Malvasia Bianca X Sultanina, Marvel
de Vaucluse X Malvasia Bianca, Molinera X Monukka, Molinera X Sultanina,
Muscat Blowers X Monukka, Muscat Blowers X Sultanina, Muscat Bowood X
Black Corinth, Muscatello Fino X Sultanina, Muscat Gigas X Alexandria, Mus-
cat Hamburg X Sultanina, Olivette Blanche X Monukka, Olivette Blanche X
Sultanina, Rambela X Monukka, Rambela X Sultanina, Trivoti X Monukka, Tri-
voti X Sultanina, Zabalkanski X Monukka.
Georgia
Grape-breeding work is entirely with Vitis rotundifolia to improve vine and fruit
qualities of the muscadine grapes. Eleven varieties have been introduced from
1919 to 1934. Breeding material includes a number of muscadine varieties and
station seedlings. Table 3 gives the varieties introduced.
Table 3. — Grape varieties introduced by the Georgia Experiment Station
Variety
Year
intro-
duced
Parentage
Qualities
1933
1934
1921
1919
1939
1933
1919
1919
1919
1919
1934
Productive; high sugar content.
ScuppernongX black male. . - .
Hunt.
Irene X unknown male _. ..
Scuppernong X black male
Scuppernong X black male
San Monta X unknown male
Large; white; sweet.
* Alphonse Lavallee is grown commercially in California under the name Ribier.
GRAPES 657
Maryland
Grape-breeding work was started in 1912. The main attempts were to develop
an early black grape of high quality. A study was made of the inheritance of
fruit color. While an early black grape of quality for Maryland conditions was
not obtained, a few seedlings were propagated in 1929 for further test, some of
which show promise as desirable varieties.
Seedlings were grown of the following open-pollinated varieties: Bailey, Brilliant,
Creveling, Goethe, Lindley, Lucile, Mericadel, Red Giant, Salem, Wilder, Wood-
ruff, Worden, Wyoming. Seedlings were also obtained from the following crosses:
Agawam X Clinton, Brighton X Winchell, Campbell X Winchell, Clinton X
Black Hamburg, Delicious X Winchell, Diana X Clinton, Diamond X Clinton,
Eclipse X Brilliant, Lindley X Clinton, Lindley X Campbell Early, Lindley X
Winchell. Moore Earlv X Winchell, Salem X Clinton, Winchell X Brilliant,
Winchell X Clinton, Winchell X Worden, Worden X Winchell, Worden X
Clinton.
Minnesota.
Grape breeding has been in progress since 1908. The early work stressed the
use of Beta as a hardy parent in combination with the higher quality varieties,
Agawam, Campbell, Concord, Delaware, Janesville, Jessica, Lutie, Salem, and
Witt. In later work since 1923, selected seedlings from these crosses have been
used in further breeding work by intercrossing, crossing with various dessert
varieties, and inbreeding. Breeding studies have been conducted, principally
with respect to winter hardiness. Selections have been made to develop homo-
zygous material for genetic studies and for superior value in breeding work.
Cytological studies have been made on pollen development with special reference
to sterility. A chromosome number of 38 was determined in the Beta grape,
using root-tip material in making the count determinations.
Missouri
Grape breeding has been in progress since 1933. Earlier crosses were made
with the objective of better quality, improved vigor, and more resistance to
disease. Seedlings have been obtained from the following grape crosses: Camp-
bell Earlv X Eaton, Columbia X 42-18, Concord X Caco, Concord X Eaton,
Concord X 42-18, Concord X Triumph, 42-2 X 42-8, 44-5 X Caco, 44-5 X
Concord, Goethe X Concord, Goethe X 42-8, Herbert X Agawam, Herbert X
Concord, Herbert X 42-8, Hubbard X Beta, Eclipse X Eaton, Eclipse X 42-8,
Eclipse X Triumph, Lindley X Caco, Lindley X Concord, Lindley X 42-8,
Lindley X 42-17, Lindley X Triumph Moore Early X Caco, Moore Early X
Concord, Muench X Beta, Muench X 42-17, Muench X Triumph, Triumph X
Concord, Triumph X Eaton, Triumph X 42-17, Triumph X Portland.
In 1935 Concord and Moore Early were crossed with Lindley, Herbert, and
Barry (Rogers hybrids) to develop self-fertile varieties with some of the desirable
qualities of the Rogers hybrids.
New York
Grape-breeding work at Geneva was started in 1888. More than 30,000 grape
seedlings nave been grown at this station. Selfing and crossing have been used
extensively. Of 282 selfed varieties and selfed seedlings, no seedling appeared
worthy of commercial trial. Three hundred and twenty-five varieties and seed-
lings have been used in the breeding work. Particular attention has been given
to vigor, hardiness, productiveness, disease resistance, and quality of fruit. In
connection with the breeding work, a study has been made of the transmission
of different characters. Reports have been made on the inheritance of stamen
characters, color of fruit, and transmission of other vine and fruit qualities.
Chromosome counts give a diploid number of 38 in the grape varieties and species
studied, excepting several Gigas strains, which give a count of 76. Some seedlings
with the triploid chromosome number have recently been produced.
In cooperation with the New York Botanical Garden, extensive breeding work
has been carried on mainly for the production of seedless varieties suitable to
eastern conditions. Reports have been issued covering this phase of the work.
From 1907 to 1937, 21 varieties have been introduced as the result of breeding
work conducted at Geneva and Frcdonia, N. Y., and in cooperation with the
New York Botanical Garden (table 4).
658
YEARBOOK, 1937
Table 4. — Crape varieties introduced by the New York State Agricultural Experiment
Station (Geneva and Fredonia)
Variety
Year
intro-
duced
1919
1930
1920
1915
1907
1927
J 928
1923
1923
1908
1922
1912
1912
1930
1921
1930
1912
1924
1930
1927
1922
Parentage
Superior characters
Brighton X (Wlnclicll X Diamond)
(GoffXDina) XSultanina _.
Brighton X Jefferson . _ ...
Goff
Goff seedling no. 19.. . . ._ _ .
Muscat Hamburg X Diamond
Brighton X Niagara
Chasselas Hose X Mills _
Triumph X ((Winchcll X Diamond)
X Jefferson).
Golden Muscat
Hanover
Very productive; large cluster; white.
Productive: red.
Productive; white.
Productive; white; early.
Medium productive; black.
Productive; early; white.
llerhert X Worden.
Winchell X Diamond.. ... ..
Medium productive; early; white.
Productive; black.
Medium productive; white.
Medium productive; red; late.
Sheridan ... _.
Stout Seedless
Herbert X Worden. _
(Triumph X Dutchess) X StiHanina
Kosca.
Fredonia X Worden ..
Mills X Ontario
Watkins
Medium productive; nearly black.
Productive; black.
High sugar; high color.
Wayne
Westfield
Mills X Ontario
Herbert X Concord Seedless. _ ..
From the following crosses at the New York (Geneva) station, 6 seedlings have
been propagated for naming, 35 for extensive trial, and 69 for a small trial:
Ontario X Sheridan, Sheridan X Ontario, Ontario X Gros Guillaume, Ontario X
Black Corinth, Ontario X Hubbard, Ontario X Moore Early, Ontario X Muscat
Hamburg, Eclipse X Portland , Iona X Ontario, Herbert X Watkins, Concord X
Sta.5 10085 (Triumph X Mills), Sta. 10115 (Triumph X Mills) X Concord, Port-
land X Moore Early, Wayne X Iona, Hubbard X Gros Guillaume, Hubbard X
Golden Muscat, Zinfandel X Ontario, Mead No. 9 X Noir Hatif de- Marseille,
Golden Muscat X Wayne, Golden Muscat X Sultanina, Sta. 10842 ((Herbert X
Triumph) X (116 X Jefferson)) X Sultana, Sta. 7408 (Ross X Mills) X Moore Earlv,
Sta. 8691 ((Iona X Vergennes) X Jefferson) X Khalili, Sta. 8691 (Iona X Vergennes)
X Muscat Hamburg, Sta. 8717 (Kensington X Triumph) X Watkins, Sta. 9104
(Triumph X Iona) X Seneca, Sta. 9104 (Triumph X Iona) X Seneca, Sta. 10420
(Muscat Hamburg X Ripley) X Khalili, Sta. 10439 (Bakator X Diamond) X Seneca,
Sta. 10526 (Muscat Hamburg X Riplev) X Melton, Sta. 10774 (Chasselas Besson X
Diana) X ((Triumph X Sta. 116) X Jefferson) X Muscat Hamburg, Sta. 10605
(Frankenthal Precoce X Diamond) X Ontario, Sta. 10108 (Triumph X Mills) X On-
tario, Sta. 10144 (Mills X Triumph) X Dunkirk, Sta. 8536 (Goff X Iona) X Ontario,
Sta. 7408 (Ross X Mills) X Ontario, Sta. 10526 (Muscat Hamburg X Riplev) X
Khalili. Principal grape varieties used in breeding work by the New York
(State) Station:8 Agawam, Barry, Berckmans, Brighton, Butler, Campbell,
Catawba, Champion, *Chasselas Golden, Chasselas Rose, Clinton, Colerain,
Collier, Concord, Concord Seedless, Cottage, Croton, Daisy, Delaware, Diamond,
Diana, Dutchess, Eclipse, Franken Riesling, Fredonia, Goethe, Golden Muscat,
♦Herbert, Hubbard, Hubbard Seedless, *Iona, Jessica, Keuka, Lindley, Lucile,
Manito, Massasoit, Melton, *Mills, Moore Early, *Muscat Hamburg, Noah,
♦Ontario, Panariti, Pekin, Petit Syrah, Portland, Regal, Ripley, Rosaki, Salem,
Secretary, Seneca, Sheridan, Stout Seedless, Triumph, Urbana, Vergennes, Wayne,
Winchell, Worden, and also station seedlings nos. 7408, 8536, 9130, and 10919.
Grape material available for breeding in addition to American Euvitis varieties
includes early-maturing vinifera varieties and the following list of unusual varie-
ties:
From Africa: Primativo, Roussanne.
French hybrids: Caperan, Commandant, Bertile, Seyve 2667, Cartier 1, Ma-
legue 2049-3, Pcage 5-10, Seibel 2, 14, 1000, 4629, 4643, 5136, 5296, 5437, 5455,
5760, 5898, 6339, 6905, Villard 2-108.
5 "Sta." denotes station seedling.
« An asterisk (*) denotes varieties that have made good parents; others may appear later.
GRAPES
659
From Hungary: Konigiu Elizabeth, Konigin der Weingarten, Malaga Bleu,
Millenium Straube, Szauter Musk.
From Union of Soviet Socialist Republics: Albourla, Aneb-el-Cadi, Apapnish
White, Buaki, Charas, Hisakasy, Maska, Muscat de Crime, Rish Baba, Rosy
Taifi, Sabsa, Said Galumi, Slmvargani, Tabyrn, Ter-Gulmer, White Chilaki.
South Dakota
Many seedlings of the wild grape of the Dakotas were grown, but little variation
and no apparent improvement over the wild tvpe was noticed. This led to the
crossing of the wild grape of the Dakotas with choice American-type grapes. The
hardiness of the wild type, Viiis vulpina, appeared to be strongly dominant, and
32 varieties that appeared hardy and that have superior fruit qualities for the more
northern regions were introduced in 1925.
Table 5 indicates the parentage and some of the superior qualities of grape
varieties introduced by the South Dakota Station.
Table 5. — Grape varieties introduced, by the South Dakota Agricultural
Experiment Station
Variety
Parentage
Qualities
Arikara
Atkan
Azita
Caddo
Chonkee
Chontay
Edapa
Emana
Eona
Lachala
Luza
Maudan
Manota
Napka
Kompah
Oglula
Onakn
Osbu
Pontigo
Hee
Santee ..
Shakoka
Siposka
Sonona
Tahama
Teopa
Tosclia
Wachopa
Wakpala
Weeota
Wetonka
Yasota .
Lady X North Dakota wild
do _.
Beta X North Dakota wild
Beta X Agawam
Lady X North Dakota wild
Massasoit X Beta ___
Merrimae X Beta
Beta X Agawam
Lady Washington X Beta
Lady X North Dakota wild
Merrimae X Beta-
Wilder X North Dakota wild...
Merrimae X Beta
Salem X Beta
Lindley X South Dakota wild..
Merrimac X Beta
Beta X Salem
Beta X Agawam
Lady X North Dakota wild
do- _
Merrimae X Beta
Lady X North Dakota wild
do
do
do
Lindley X South Dakota wild..
Lady X North Dakota wild
Lady Washington X Beta
Merrimae X Beta
Lady Washington X Beta _
Beta X Salem
Merrimae X Beta. __ _.
White; productive; large.
White; sweet; long bunch.
Sweet; vigorous; medium size.
Black; sweet; good flavor.
White; productive; vigorous.
Black; vigorous; good flavor.
Black; large; good quality.
Black; large; good flavor.
White; productive; sweet.
White; productive; large.
Red; sweet; meaty.
Black; productive; early.
Black; large; good quality.
Black; vigorous; good flavor.
Black; large; good flavor.
Black; productive; large.
White; productive; large.
Black; medium size; good flavor.
Light red; very large; sweet.
White; productive; late.
Black; productive; large.
Black; vigorous; targe.
Black; large.
Light red; productive; sweet.
Black; vigorous; large.
White; sweet.
White; sweet; large.
Do.
Black; very large; good flavor.
White; sweet.
Black; productive; vigorous.
Black; large; wild flavor.
Texas
Grape-breeding work started in 1935. Seedlings of selfed and crossed varieties
are being obtained in an attempt to improve fruiting varieties relative to vigor,
adaptability, disease resistance, and fruit qualities. Breeding material includes
vinifera and native varieties and native grape species. Seedlings have been
obtained from the following selfed varieties: Allaga, Elvicand, Extra, Lomanto,
Marguerite, Mathilda, and R. W. Munson.
Virginia
Grape-breeding work started in 1930 by raising seedlings of open-pollinated
standard varieties. Varietal crosses of American native varieties were made in
1935. The main objective is to improve the flesh quality. A study is being
made of pollen compatibility, fruit characters, and resistance to disease.
From open-pollinated blossoms seedlings have been grown from the following
varieties: Catawba, Concord, Eumelan, Moore Early, Niagara, and Worden.
Seedlings are also being grown from the following controlled crosses: Agawam X
Amber Queen, Agawam X Barry, Agawam X V. L. B., Amber Queen X Agawam,
660 YEARBOOK, 1937
Amber Queen X Catawba, Eumelan X Catawba, Eumelan X Delaware, Eumelan X
Wilder, Eumelan X Worden, Eumelan X V. L. B., Niagara X Worden, Wilder X
Amber Queen, and selfed seedlings of Agawam, Catawba, Delaware, and Regal.
Two seedlings of earlier crosses were introduced in 1936: V. L. B. (Campbell
Early X Herbert) and Agel (Agawam X Regal) .
United States Department of Agriculture
Grape-breeding work was started with vinifera varieties at Fresno, Calif., in
1923, to produce seedless varieties suitable for table and raisin use, quality table
varieties, and juice varieties Crosses have been made between many vinifera
varieties, using the seedless varieties as the male parents. _ Large-berry varieties
have been used to increase size, and highly flavored varieties to improve quality.
Seedlings of standard varieties, selfed seedlings, and backcrosses are being grown
to study genetic characters and the possibility of obtaining desirable qualities.
Some cytological work has been done on pollen development and the develop-
ment of the ovule. Studies have been made on the inheritance of vine, flower,
and fruit characters.
Seedlings are being grown of phylloxera-resistant stock varieties and crosses
of stock varieties for further studies on rootstocks resistant to root knot nematode.
Varietal improvement through the selection of bud sports is in progress. Pub-
lications have been issued on the progress of the breeding work and the produc-
tion of seedless varieties. Grape-breeding material includes 338 American native
varieties, 95 Franco-American direct producers, 136 phylloxera-resistant root-
stocks, over 550 varieties of Vitis vinifera, and in addition over 200 more recent
Plant Introduction numbers from foreign sources.
Seedlings of the following crosses have been obtained: Alexandria X Alicante
Bouschet, Alexandria X Monukka, Alexandria X Calmette, Alexandria X
Corinthe Blanc, Alexandria X Corinthe Rose, Alexandria X Damas Rose,
Alexandria X Hunisa, Alexandria X Malaga, Alexandria X Panariti, Alex-
andria X Sultanina, Alexandria X Sultanina Gigas, Alexandria X Sultanina
Rosea, Emperor X Monukka, Emperor X Maraville de Malaga, Emperor X
Sultanina, Flame Tokay X Monukka, Flame Tokay X Maraville de Malaga,
Flame Tokay X Sultanina, Gros Guillaume X Monukka, Gros Guillaume X
Maskah, Gros Guillaume X Sultanina Gigas, Malaga X Monukka, Malaga X
Sultanina, Maraville de Malaga X Monukka, Maraville de Malaga X Sultanina,
Maraville de Malaga X Sultanina Gigas, Maraville de Malaga X Tagonti Rouge,
Maskah X Gros Guillaume, Muscat Hamburg X Monukka, Muscat Hamburg X
Panariti, Ohanez X Monukka, Panariti (sport) X Monukka, Pizzutella X Monuk-
ka, Rodites X Monukka, Rodites X Gros Guillaume, VignedeZericho X Rodites.
Seedlings have been obtained from crosses of station seedlings and standard
varieties as follows: (Alexandria X Monukka) 9642 X Monukka, (Alexandria X
Monukka) 96419 X Monukka, (Alexandria X Corinthe Rose) 105616 X Monukka,
(Alexandria X Corinthe Rose) 105713 X Monukka, (Alexandria X Sultanina)
96212 X Sultanina, (Damas Rose X Monukka) 8635 X Monukka, (Damas Rose
X Monukka) 86310 X Monukka, (Damas Rose X Monukka) 8649 X Sultanina
Gigas, (Damas Rose X Monukka) 86311 X Sultanina Gigas, (Muscat Hamburg
X Monukka) 106212 X Monukka, (Muscat Hamburg X Monukka) 106312 X Mo-
nukka, (Pizzutella X Monukka) 10644 X Monukka, (Pizzutella X Monukka) 10649
X Monukka, and Muscat Hamburg X (Alexandria X Sultanina Rosea) 96212.
Seedlings of the following selfed varieties are being grown: Agadia, Alexandria,
Carignane, Chasselas Cioutat, Chasselas Dore, Chasselas Rose de Falloux,
Cinsaut, Crabbs Burgundy, Emperor, Flame Tokay, Foster, Gros Guillaume,
Lenoir, Malaga, Maraville de Malaga, Maskah, Mission, Muscat Hamburg,
Mondeuse, Panariti, Palomino, Petit Syrah, Prune de Cazouls, Sauvignon Vert,
Semillon, Sylvaner, Traminer, Zeine, Zinfandel, and seedlings of the following
Plant Introduction nos. 105074 to 107086, inclusive, 105922, and 107007.
Seedlings of the following selfed station seedlings are being grown: (Alexan-
dria X Alicante Bouschet) 9582, (Alexandria X Alicante Bouschet) 95915, (Alex-
andria X Alicante Bouschet) 95919, (Alexandria X Monukka) 9623, (Alexan-
dria X Monukka) 9627, (Alexandria X Monukka) 9628, (Alexandria X
Monukka) 96311, (Alexandria X Monukka) 96317, (Alexandria X Monukka)
96319, (Alexandria X Monukka) 9642, (Alexandria X Monukka) 9646, (Alex-
andria X Monukka) 96419, (Alexandria X Calmette) 96017, (Alexandria X
Corinthe Rose) 105616, (Alexandria X Malaga) 9571, (Alexandria X Malaga)
GRAPES 661
95818, (Alexandria X Malaga) 10587, (Alexandria X Malaga) 105915, (Alex-
andria X Panariti) 9603, (Alexandria X Panariti) 9118, (Alexandria X Sul-
tanina) 96212, (Alexandria X Sultanina Rosea) 9612, (Alexandria X Sultanina
Rosea) 96216, (Muscat Hamburg X Monukka) 106211, (Muscat Hamburg X
Monukka) 106212, (Muscat Hamburg X Monukka) 10633, (Muscat Hamburg X
Monukka) 10637, (Muscat Hamburg X Monukka) 106312, (Muscat Hamburg X
Monukka) 106316, (Muscat Hamburg X Panariti) 8621, (Muscat Hamburg X
Panariti) 8623, (Olivette Blanche X Muscat Hamburg) 10616, (Olivette
Blanche X Muscat Hamburg) 10626, (Olivette Blanche X Olivette Noire) 9563,
(Olivette Blanche X Olivette Noire) 9564, (Olivette Blanche X Olivette Noire)
9566, (Olivette Blanche X Olivette Noire) 9572, (Pizzutella X Monukka) 10649.
Seedling? of Vinifera grape crosses that have fruited at the Fresno station of the United
States Department of Agriculture
Parentage Superior qualities obtained
Alexandria X Alicante Bouschet __ Productive; vigorous; red juice; rich flavor.
Alexandria X Monukka Productive; vigorous; seedless; muscat flavor;
adherence.
Alexandria X Calmette Productive; red juice; rich flavor.
Alexandria X White Corinth Productive; all white fruit.
Alexandria X Corinthe Rose Productive; some red fruit; rich flavor.
Alexandria X Damas Rose Productive; large-size berry.
Alexandria X Hunisa Vigorous.
Alexandria X Malaga Productive; large-size cluster and berry;
rich flavor.
Alexandria X Panariti Productive; none seedless.
Alexandria X Sultanina Productive; vigorous; seedless; no muscat
flavor.
Alexandria X Sultanina Rosea Productive: vigorous.
Damas Rose X Monukka Productive; vigorous; large size; some seedless.
Gros Guillaume X Monukka Adherence; large size; seedless,
Muscat Hamburg X Monukka Productive; muscat flavor; some seedless.
Muscat Hamburg X Panariti Productive; small size; none seedless.
Ohanez X Monukka Seedless; late ripening.
Olivette Blanche X Muscat Ham- Elongated types; muscat flavor.
burg.
Olivette Blanche X Olivette Noire _ Elongated types; white, red, and black
colored fruit.
Pizzutella X Monukka i Elongated fruit types; seedless; early ripening.
Rodites X Monukka . Late ripening; seedless.
Rodites X Gros Guillaume Late ripening; firmness of fruit.
Grape-breeding work with native American grapes and Vilis vinifera has been
in progress at Arlington, Va,, and Beltsville, Md., since 1933, to originate seedless
varieties and to improve the quality and adaptability of native American varieties
especially for central and southern regions.
Seedlings of the following varieties are under observation at the Beltsville
station: August Giant, Bailey, Black Eagle, Caco, Captain, Captivator, Ellen
Scott, Eumeian, Golden Muscat, Goff, Manito, Mills, Nitodal, Norwood, Oriental,
Rogers nos. 13, 32, 33, Urbana.
Seedlings have been obtained of the following native bunch grape crosses:
Bailey X Brilliant Seedling, Captivator X Beacon, Captivator X Columbian
Imperial, Captivator X Fredonia, Champanel X Manito, Champanel X Niagara,
Columbian Imperial X Empire State, Delaware X Goethe, Empire State X
Manito, Goethe X Delaware, Lenoir X Salem, Loretto X Oriental, Manito X
Caco, Manito X Empire State, Oriental X Portland, Rogers 13 X Beta.
Seedlings have been obtained of the following native American bunch grapes
and vinifera crosses: Atoka X Gros Guillaume, Bailey X Foster, Bailey X
Goolabie, Bailey X Gros Guillaume, Blauer Portugieser'X Monukka, Campbell
Early X Monukka, Campbell Early X Alphonse Lavallee (Ribier 7), Captain X
Goolabie, Captivator X Monukka/Captivator X Alphonse Lavallee, Catawba X
Monukka, Catawba X Muscat Hamburg, Catawba X Alphonse Lavallee,
Catawba X Sultanina, Cloeta X Goolabie, Cloeta X Muscat Hamburg, Colum-
bian Imperial X Monukka, Columbian Imperial X Goolabie, Concord X Monuk-
' See footnote 4, p. 658.
662 YEARBOOK, 1937
ka, Concord X Sultaniiia, Ellon Scott X Sultanina, Lucile X Monukka, Manito
X Chasselas dc Fontainebeau, Manito X Alphonse Lavallee, Niagara X Sul-
tanina, Ontario X Blauer Portugieser, Oriental X Albardicns, Oriental X Monuk-
ka, Oriental X Goolabie, Oriental X Muscat Hamburg, Oriental X Panariti
Oriental X Sultanina, Portland X Blauer Portugieser, Triumph X Monukka,
Vergennes X Monukka, Vergennes X Alphonse Lavallee.
Muscadme grape-breeding work of the Department has been centered at the
North Carolina State Department of Agriculture Test Farm, Willard, N. C.
This work was started in 1907. From two early crosses, two perfect-flowered
hermaphrodite seedlings were obtained. By selfing one of these plants, and
also by using the pollen from this type to pollinate standard muscadine varieties,
an additional number of perfect-flowered seedlings were obtained. Better berry
adherence, increased productivity, and improved fruit quality have been reported.
True hybrids were obtained between Vitis roiundifolia and V. vinifera, and also
between V. roiundifolia and varieties of American bunch-type grapes.
The following hybrid seedlings of Vitis roiundifolia and varieties of American
bunch-type grapes obtained at Willard, have been selected for further study:
James X Winchell, Labama X Brilliant, muscadine seedling X Campbell Early,
muscadine seedling X Catawba, muscadine seedling X Delaware, muscadine
seedling X Goethe, muscadine seedling X Winchell, Scuppernong X Louisiana,
San Jacinto X Ives, Thomas X Concord, Thomas X Goethe.
The following hybrid seedlings of Vitis roiundifolia and V. vinifera have been se-
lected for further study: George X Goolabie, muscadine seedling X Black Morocco,
muscadine seedling X Semillon, San Alba X Malaga, San Alba X Semillon, San
Jacinto X Malaga, Thomas X Black Morocco, Thomas X Maraville de Malaga.
Muscadine seedlings selected for further trial are the following: 10- Latham X
(Eden X (Eden X male Munsoniana)), 14- Latham X (Thomas X (Eden X
(Eden X male Munsoniana))), 3- Latham X male (muscadine seedling X (Eden X
(Eden X male Munsoniana))), 1- Latham X male (muscadine seedling X (Eden X
male Munsoniana)), 8- Luola X (Eden X (Eden X (Eden X male Munsoniana))),
3-Luola X (Thomas X (Eden X (Eden X male Munsoniana))), 5- Luola X (mus-
cadine seedling X (Eden X (Eden X male Munsoniana))), 1- Luola X (muscadine
seedling X (Eden X (Eden X male Munsoniana))), 1- San Alba X (Eden X
(Eden X male Munsoniana)), 2- San Alba X male (Eden X (Eden X male
Munsoniana)), 6- San Alba X (Thomas X (Eden X (Eden X male Munsoniana))),
3- San Alba X (muscadine seedling X (Eden X male Munsoniana)), 5- San
Rubra X male (Eden X (Eden X male Munsoniana)), 3- San Rubra X (Eden X
(Eden X male Munsoniana), 1- San Rubra X (Thomas X (Eden X (Eden X
male Munsoniana))), 1- muscadine seedling X (Eden X (Eden X male Munsoniana)),
1- muscadine seedling X male (Eden X male Munsoniana), 1- muscadine seed-
ling X (muscadine seedling X (Eden X (Eden X male Munsoniana))), 13- mus-
cadine seedling X male (Eden X (Eden X male Munsoniana)), 1- muscadine
seedling X (Eden X (Eden X male Munsoniana)), 2- muscadine seedling X
(muscadine seedling X (Eden X (Eden X male Munsoniana))), 20- muscadine
seedling X (muscadine seedling X (Eden X (Eden X male Munsoniana))), 3-
muscadine seedling X (Eden X male Munsoniana), 1- (Eden X (Eden X male
Munsoniana)) X male (Eden X (Eden X male Munsoniana)), 3- (James X white
male) X (Eden X (Eden X male Munsoniana)), 2- (James X white male) X
(muscadine seedling X (Eden X (Eden X male Munsoniana))), 1- James seedling
X (muscadine seedling X (Eden X (Eden X male Munsoniana))), 1- muscadine
seedling X male (Eden X (Eden X male Munsoniana)), 1-selfed seedling (James
X (Eden X (Eden X male Munsoniana))), 3- self ed seedlings (Thomas X (Eden
X (Eden X male Munsoniana))), 1- selfed seedling (muscadine seedling X (Eden
X (Eden X male Munsoniana))), 2- selfed seedlings (muscadine seedling X
(Eden X (Eden X male Munsoniana))). (All pollen parents were hermaphrodite
seedlings unless designated as male.)
Vinifera grape varieties available for breeding work in United States Department oj
Agrieulture experiment vineyards 8
[Alphabetically arranged]
Ach-I-Soum, Affen thaler, Agadia, Agra Ash, Ak Saibe, Aibatly Isium, Ajmi,
Ak-usum, Aldara, Aleatico, Alexandria, Alicante, Alicante Bouschet, Alnwick
* This list contains many names of Persian or other foreign origin thathave no exact English equivalent
and also includes some recent introductions that have not yet found a place in American grape literature,
Such names are to be regarded as tentative and not necessarily authentic and final.
GRAPES 663
seedling, Alvarna, Amlachu, Aneb-el-Cadi, Angur Khalili, Angur Noir Grande,
Apapnish White, Appley Towers, Aramon, Ascot Citronelle, Askaree, Asmi,
Aspiran Noir, Ateh Gau, Augulato, Awasarghua.
Baba, Bakator, Barbarossa, Barbera, BarduccI, Bastardo, Beclan, Bellino,
Bengi, Bermestia Violacca, Bicane, Black Alicante, Black Hamburg, Black
Morocco, Black Prince, Black Seedless, Black Shahance, Black Zante (South
Africa currant grape), Blanc d'Ambre, Blaney White, Blauer Portugieser, Boal
de Madeira, Bocalilla, Bolgnino, Bonarda, Boudelais, Bowood Muscat, Brustiauo,
Buaki, Buccleuch, Bucldand Sweetwater, Buhirzi, Burger.
Cabernet Sauvignon, Calabrian, Calmette, Camion Hall Muscat, Carignane,
Castiza, Cefid, Ceskarg Charial, Chabach, Chali Sar, Chani Rouge, Chaouch
blanc, Chaouch Rose, Charas, Chasselas Ciotat, Chasselas de Fontainebleau,
Chasselas Rose de Falloux, Cliasselas Rouge, Chasselas St. Bernard, Chaweesh,
Child of Hall, Chirazi, Chauch Gris, Chauch Noir, Cinsaut, Cipro Nero'
Clairette a Gros Grain, Coarna Neagra, Corazon de Cabrito, Corinthe a Gros
Grain, Corinthe Rose, Coristano, Crabbs Burgundy.
Damas Rose, Danugue, Dattier de Beyrouth, Deis-cl-A'anze, Diamond Jubilee,
Directeur Tisserand, Dizmar, Doctor Hogg, Drnekusa, Dronkane, Due de
Malakoff, Duchess of Buccleuch, Duke of Buccleuch.
Empei'or, Esandri, Eskari Riz, Etraire do l'Adhui.
Fajaumi Jaune, Paphly, Peher Szagos, Feher Som, Fintendo, Flame Tokay,
Foster, Frankenthal Precoee, Fredericton.
Gamay de Bourgogne, Gamay Teinturier, Gewttrz Traminer, Ghiliaki Krasnaya,
Ghulabi Black, Ghulabi Red, Ghusaine, Golden Champion, Golden Hamburg,
Goolabie, Gradiska, Grove End Sweetwater, Green Hungarian, Grenache, Gros
Blanc de Lausanne, Gros Colman, Gros Guillaume, Gros Manzenc, Gros Verdot,
Guadalupe.
Hebron, Hunisa, Hycales.
Imperial Blanc, Insolia Bianca, Italia Elqui.
J'bai, Johannisberger, Juboili..
Kabasma, Kabbajuk, Kadarka, Kahalillee, Kharashani, Kara-Usum, Karoo
Belle, Kasufi-Dakar, Kasufi inti, Katta-Kurgan, Kechwechi Bleue, Kechwechi
Rouge, Keropodia, Kandiliar, Khasseyne, Klmdud-ul-Banat, Kishmish daba,
Kolner, Koptchak, Koshu, Ksil-isjum, Kurdi, Kurtelaska.
Lady Downe, Lady Hastings, Ladj' Hutt, Lai Cefid, Lai Guermez, La Mollar,
Larien, Leani Zolo, Lignan Blanc, Lore Koche, Luglienga Nera.
Macaboe de Satin, Madeleine Angcviue, Madeleine d'Ambre, Madeleine Royale,
Madresfield Court, Malaga, Malaga Rose, Malakoff Isjum, Malvasia de Broglfana,
Malvasia Rosaria, Malvasia Rovasenda, Mamelon, Mantuo di Pilo, Marmora,
Marascina, Marzamina Genuina, Maskah (Nos. 24772, 24774, 24775, 24776,
24781, 24782, 24783, 24784, 24785, 24786, 24787, 24788, 24792, 24793), Mataro,
Melhi Khany, Melton Constable, Meslier Hatif, Meunier, Miksasi, Millenium,
Mission, Monakc, Mon. Deludda, Mondeuse, Monukka, Mourastel, Mourisco
Bianca, Mourisco Preto, Mrs. Pince, Mskhali, Mukhkh-ul-Baghl, Muscatel Com-
mune, Muscat Bonod, Muscat Capusines, Muscat de Frontignan, Muscat Gros
Noir Hatif, Muscat Hamburg, Muscat Noir d'Hougrie, Muscat Noir Precoee,
Muscat Rose, Muscat Talabot.
Nasa Valentiana, Nebbiolo, Nebbiolo Botirgu, Nebbiolo Fino, Negro Amaro,
Negrara di Gattinara, Negra Elqui, Negra Nero, Nimrang.
Ohanez, Ojo de Liebre, Olivette Blanche, Olivette de Vendemain, Olivette
Noire, Opimau.
Pagadebito, Palarusa, Palomino, Panariti, Pare do Versailles, Pastilla Elqui
Paykanee Razuki, Perle de Csaba, Pedro Ximines, Perle Imperial Blanche, Per-
runo, Persian (no number), Persian (no tag), Persian (nos. 21-26), Petit Syrah,
Petit Verdot, Peverella, Piment, Pince Muscat, Pineau de Chardonnay, Pineau
Noir Epernay, Pinot St. George, Pirovano, Pizzutella, Plavai, Poulsard, Pomology
No. 08091, Prince of Wales, Prune de Cazouls, Purple Damascus.
Quagliano, Quanque.
Red Hanepoot, Refosco, Rka-tzital, Robin Noir, Rodites, Ronde Weisse, Rose
d'ltalia, Rose of Peru, Rothgipfler, Rousseau, Royal Ascot.
Schach-I-Soum, Sahibi, Sahibi Charial, Saidi, San Giovctto, Satin Blanc, Sau-
vignon Blanc, Sauvignon Vert, Schiradzouli Blanc, Schiradzouli Violet, Semillon,
Serektia, Serine, Servan Blanc, Servan Rose, Schaani, Shahmani, Shakaifi, Shanzi,
664 YEARBOOK, 1937
Shirshira, Shuvarghani, Sicilian, Slankamenka, Souvenir du Congres, St. Lauriont,
St. Macaire, Sufetha, Sultana, Sultanina, Sultanina Rosea, Suri, Sylvaner.
Tadone, Tagonte Rouge, Tanfi Rose, Tannat, Tavris (no. 27963, 30467), Tenc-
ron de Cadenet, Tifafihi Ahmcr, Tinta Amerella, Tinta Cao, Tinta de Madeire,
Trentham Black, Trojka, Trousseau.
Ubeide, Umagum, Uva de Casta.
Valandova, Valdepenas, Veltliner, Verdel, Vermentino, Vigne de Zericho.
Walschriesling, Wcrme, West Prolific, White Corinth, White Frontignan,
White Nice, White Tokay, Wilmot No. 16.
Zabalskanski, Zeine, Zenkoji, Zinfandel, Zinzillosa.
Grape rootstock varieties available for breeding work in United States Department of
Agriculture experiment vineyards
[Alphabetically arranged]
Adobe Giant; (Vitis aestivalis X monticola) X (V. riparia X ru pesiris) , no. 554-5;
(V. aestivalis X rupestris) X riparia, no. 227; Alicante Bouschet X V. cordifolia,
no. 142-B; Alicante Bouschet X V. riparia, no. 141-A; Aramon X V. riparia,
no. 143-A; Aramon X Rupestris Ganzin (nos. 1, 2, 9); Arizonica Phoenix;
Australis.
Barnes; Vitis berlandieri (nos. 1, 2); BerlandieriLafont, no. 9; V. berlandieri X
riparia (nos. 33 E. M., 34 E. M., 157-11, 420-A, 420-B); (Bpurrisquou X V.
rupestris, no. 601) X Calcicola, no. 13205.
Cabernet X V. berlandieri, no. 333 E. M.; Cabernet X Rupestris Ganzin,
no. 33-A; Chasselas X V. berlandieri, no. 41-B; (V. cinerea X rupestris) X riparia,
no. 229; Columbaud X V. riparia, no. 2502; Constantia; V. cordifolia X riparia,
no. 125-1.
DeGrassett; Dog Ridge.
Hotporup.
Joly; Judge.
V. monlicola X riparia (nos. 18804, 18808, 18815); V. monticola X rupestris;
Motley; Mourvedre X V. rupestris (nos. 1202, 1203).
Pinot Bouschet X V. riparia, no. 3001; Pinot X V. rupestris, no. 1305; Ponroy.
Ramsey; Riparia Gloire; V. riparia X berlandieri, no. 161-49; V. riparia X
(cordifoliaX rupesiris),no. 106-8; Riparia Grand Glabre X (Aramon X V. rupestris),
no. 4110; V. riparia X rupestris (nos. 101, 101-14, 108-103, 3306, 3309) ; V. riparia X
V. rupestris, Jaeger; V. riparia X (rupestris X Aramon), Jaeger, no. 201; V. riparia X
Rupestris Ramond; Rupestris des Causettes; Rupestris des Semis, no. 81-2;
Rupestris Ganzin; Rupestris Le Reux; Rupestris Martin; -Rupestris Metallica;
Rupestris Mission; Rupestris Othello; Rupestris Pillans; Rupestris St. George;
V. rupestris X berlandieri (nos. 219-A, 301-A, 301-B, 301-37-152) ; V. rupestris X
Chasselas Rose, no. 4401; V. rupestris X cinerea; V. rupestris X cordifolia, no.
107-11; V. rupestris X (cordifolia X rupestris), no. 202-5; V. rupestris X
Azemar, no. 215; V. rupestris X Petit Bouschet, no. 503; V. rupestris X Petit
Bouschet, no. 504; V. rupestris X riparia, no. 108-16.
Salt Creek; Solonis Ordinaire; Solonis Robusta; Solonis X (V. cordifolia X
rupestris), no. 202-4; Solonis (V. longii) X Othello ((V. riparia X labrusca) X
vinifera), no. 1613; Solonis X V. riparia (nos. 1615, .1616).
Taylor Narbonne; Tisserand.
Vermorel; Viala; Viala X V. riparia; V. candicans.
York X Rupestris Ganzin, no. 212.
Direct-producing grape varieties available for breeding work in United States Department
of Agriculture experiment vineyards
Bourrisquou X Vitis rupestris (nos. 601, 603, 109-4, 3907, 4306, 4308).
Carignane X V. rupestris (nos. 404, 501); Castel (nos. 1028, 19002); Clairette
Dore Ganzin; Couderc (nos. 101, 201, 503, 704, 3701, 4401, 28 X 112, 71-06,
71-20,74-17, 82-32, 4 X 61, 85 X 113, 87 X 115, 124 X 30, 132-11, 199-88
241-55,267-27,272-60). ' '
Seibel (nos. 1, 2, 14, 29, 38, 60, 70, 78, 80, 128, 156, 209, 215, 334, 1004, 1070,
1077, 2010, 2029, 2033, 2043, 2044, 2056).
IMPROVEMENT OF
STONE FRUITS
F. P. CULLJNAN, Senior Penologist,
Division of Fruit and Vegetable Crops
and Diseases, Bureau of Plant Industry1
JL HE beautiful and delicious varieties of peaches, plums, cherries,
and apricots that make up the group of stone fruits as we know them
today are undoubtedly vastly different from their early progenitors.
Down through the centuries many wild species and varieties have
been selected by man in his search for new food supplies and a better
diet. Just how long this slow process of improvement of the various
kinds of wild fruit has been going on, history does not relate. As
civilization progressed we know that many of these wild fruits were
taken from their native homes and distributed to new locations where
there were new soils and new climatic conditions. In these new
environments certain modifications occurred in size of tree and in
size, shape, color, and flavor of fruit. Many trees perished in the
new environments. Perhaps only a few survived the vicissitudes of
climate in some of the regions into which they were taken. Through
these early chance selections, however, a beginning was made in the
improvement of the stone fruits.
Stone fruits are now grown in all parts of the Temperate Zone in
the Northern Hemisphere. In the United States the culture, produc-
tion, and sale of these fruits constitute a great industry. In 1931, the
peak year of peach production, the commercial crop was over 76K
million bushels. According to the census of 1935, the country pro-
duced in the previous year about 45 million bushels of peaches, over
23 million bushels of plums, and 5 million bushels of cherries. Peaches,
plums, and apricots in the fresh, canned, and dried state are consumed
in large quantities in this country and abroad. About 200,000 tons
of peaches are dried in the United States annually. California alone
produces about 75 percent of the world output of dried prunes.
Cherries are commercially important as fresh, canned, and frozen
products. There is little wonder that such a great industry should
demonstrate weaknesses in many of our long-cherished varieties of
home-grown fruits. We might imagine that after all these years of
selection and discovery of new sorts, we would have reached perfec-
tion. Unfortunately, this is not the case; in fact, it may be said that
1 The author wishes to acknowledge his indebtedness to the following workers engaged in stone-fruit
breeding in this country and abroad for their kind cooperation in furnishing information on the work in
progress in their respective States and in furnishing lists of varietal and species material available for breed-
ing studies: W. A. Alderman, Minnesota; J. S. Bailey, Massachusetts; M. A. Blake, New Jersey; M. J.
Dorsey, Illinois; N. E. Hansen, South Dakota; F. W. HofMann, Virginia; Stanley Johnston, Michigan;
T. J. Maney, Iowa; W. P. Tufts, O. L. Philp, E. O. Hughes, and J. W. Lesley, California; Richard
Wellington, New York; S. H. Yarnell, Texas,; A. F. Yeager, North Dakota; W. F. Wight, U. S. Bureau of
Plant Industry, Palo Alto, Calif.; W. P. Baird, U. S. Northern Great Plains Field Station, Mandan,
N. Dak.; E. F. Palmer and Q. H. Dickson, Vineland, Ontario, Canada; II. Wenholz, New South Wales
Department of Agriculture; and M. Oh. Miedzyrzccki, Aiu Taoujdat, Morocco.
665
138004°— 37 43 -I-+
666 YEARBOOK, 193 7
the work of improvement has just begun. We must continue the
search for superior fruits, locating and studying the best raw mate-
rials, and then using the methods available to the plant breeder to
combine desirable characters in a superior progeny.
BOTANY OF THE STONE FRUITS
Before attempting to consider the progress made in improving the
varieties of stone fruits, a few words should be said about the botany
of these fruits in general.
Botanists have classified the stone fruits into several species. While
there has not been entire agreement as to the number of these species,
most botanists place them in the great genus Prunus in the rose family
(Rosaceae) ; others, however, separate the peach and its close relatives
as the genus Amygdalus. The fruit develops from a one-celled ovary
the wall of which ripens with a fleshy, juicy exterior, making up the
edible part of the fruit, and a hard interior, called the stone or pit.
The seed is contained in the stony portion.
But while these fruits have enough in common to be grouped in the
same genus, they are quite different in many fruit, flower, and tree
characters. When the fruits are ripe the flesh of some varieties parts
readily from the pit. Such fruits are spoken of as freestones. Other
varieties and species, for example, the canning cling type of peaches,
are clingstones; that is, the flesh adheres to the stone. The indi-
vidual fruits may be smooth, as in the apricot, nectarine, plum, and
cherry, or hairy, as in the peach. They vary in size, color, and shape
THE kind of search in which the breeder of peaches is engaged may
be illustrated by the Elberta. This is the leading commercial peach
in the United States today. It originated in Marshallville, Ga.,
in 1870, and in the 67 years since that time no better peach has
been found, when all characteristics are considered. Yet in quality
the Elberta does not rank as high as some other peaches, and the
tree and the blossom buds are not sufficiently resistant to low ivinter
temperatures. By suitable crosses, varieties have been developed
that have better quality and more cold resistance in the bud; but these
in turn are not adapted to so many different growing regions as the
Elberta. Again, seedlings of Elberta have been found that ripen
earlier than the parent variety and are better in quality and more
attractive. It would seem possible, then, to develop a variety that
would be a distinct improvement over Elberta, yet possess the valu-
able characteristics that have given the Elberta preeminence. Such
an achievement would be a major contribution to fruit culture in
the United States.
STONE FRUITS 667
with varieties and species. The flesh may be yellow, green, white,
or rod, or show various combinations of these colors. The stones or
pits of the peach are rough and grooved, those of the plum and cheny
relatively smooth, those of the apricot somewhat intermediate.
The flowers of the different stone fruits are quite characteristic for
the respective groups. In the peach and the apricot they are borne
singly, arising from one to three separate buds at a node. They are
practically without stems in the peach, and nearly so in the apricot.
They are on long stems in the cherry and on only moderately long ones
in the plum, but in both these fruits the flowers are borne in clusters.
The flowers of the edible plums are white or nearly so, while those of
the peach and the apricot may be white, pink, or reddish.
As will bo pointed out later, hybridization between some of the
species of stone fruits is practically impossible.
METHODS OF BREEDING
The technique of stone-fruit breeding is not greatly different from
that employed with other deciduous fruits. The essential operations
are (1) collecting pollen to be used in the crosses, (2) emasculation of
the flowers, (3) pollination, or the actual transfer of pollen to the
stigmas of the pistil, (4) bagging, or protecting flowers from foreign
pollen, (5) protecting fruit that has set, and (6) growing the seedlings
for testing and study of the progeny.
Much of the breeding work with stone fruits is carried on with trees
growing in the orchard. This has its drawbacks as well as many
advantages. Blossom buds, flowers, or young developing fruits may
be killed by cold. Under such conditions the continuity of breeding
work is interrupted and a year's time is frequently lost. To avoid
this difficulty, particularly in the regions of unfavorable climate, it
has been found satisfactory to grow the trees in tubs or pots in the
greenhouse. Emasculation and pollination can thus be carried on
under controlled temperature. Since it is necessary for most stone
fruits to have sufficient cold to bring them out of the rest period, the
trees in tubs must bo removed from the greenhouse in late summer or
fall and placed out of doors or in a cool storage place. They may be
brought back to the warm greenhouse by the middle of January, and
the trees should then bloom in 3 or 4 weeks. While greenhouse trees
do not reach the large size of those growing in the field and conse-
quently do not produce as many blossoms, sufficient material can
usually be obtained for certain crosses and for genetic and cytological
study. In some cases it may be the only way blossoms can be pro-
duced for breeding work.
In obtaining pollen to be used in breeding it is usually necessary to
collect shoots of the male parents desired and force the blossoms in
a greenhouse or warm room in order to have the pollen available when
the flowers on the tree are ready for pollination. Care should be
taken, of course, that no foreign pollen is introduced by bees or other
insects. When the flowers have opened, the anthers may be plucked
off by running the filaments through a comb or some similar instrument
that will lift off the anthers, which may then be placed in suitable
containers to dry at room temperature of 65° to 70° F. When dry
they break open and the pollen can be easily crushed out. The pollen
668
YEARBOOK, 1937
— petal
cr/itAer
■d-tijrma
--filament
~~y style
--sepal
should be stored in a dry, cool place in vials or small boxes, from which
it may be used directly when the crosses are made. It is convenient
to leave a small camel's-hair brush in each container to use in the
transfer of pollen.
The structure of the flowers of the peach and other stone fruits permits
rapid emasculation. The stamens and the single pistil are enclosed
under the folded petals. As the blossom expands from the bud scales,
the calyx pushes up, carrying the nonexpanded leafy floral structures,
forming a cup around the ovary. The long style of the pistil grows
up through the stamens and under certain conditions may even push
through between the petals before they expand (fig. 1). In the tech-
nique of emasculating,
the calyx cup is easily
cut with the nails of
the thumb and first
finger, and the entire
corolla with its three
rows of stamens at-
tached may be lifted
from the flower, leav-
ing the pistil undis-
turbed. Early work-
ers used sharp-pointed
tweezers or scissors to
cut the calyx cup, but
the fingernail method
is more rapid. With
varieties of peach that
are pollen-sterile, or
varieties of plums and
cherries that are self-
unfruitful, emascula-
tion is unnecessary in
ordinary hybridiza-
tion. A small percent-
age (0.5-0.8) of set is sometimes obtained in selfing self-unfruitful
varieties. While this is a negligible amount in variety breeding, it
should not be overlooked in cytological studies.
If emasculation is done just before the petals open (fig. 2) — which is
just before any pollen that might cause selfing has been shed — the
pollen of the parent to be used in the cross may be applied to the
stigmas at once. Where a large number of pollinations are made on
a single tree, it is frequently convenient to emasculate all the blossoms
before pollinating. With the aid of the camel's-hair brush, from the
pollen container a large number of flowers can be pollinated in a short
time. Some workers prefer to use the tip of the finger, to which the
pollen will adhere, and apply the pollen by touching the stigmas. Care
should be taken to remove all pollen grains of one variety or strain from
the finger before dipping into a container of another variety. The indi-
vidual blossoms, single shoots, or entire branches that have been polli-
nated with a single pollen variety should be carefully labeled with full
data on a tag or label that will remain until the fruit is harvested.
'■ ovary
Figure 1. — Scclion through a peach flower showing
arrangement of floral parts. By pinching through the
calyx cup at a with the thumb and first finger, sepals,
petals, and stamens are all removed in one operation,
leaving the single pistil.
STONE FRUITS
669
Figure 2. — Flower buds of peach (lefl) showing ideal slage for emasculation. Within
24 hours with temperatures of 70° to 75° F. the flowers will open as shown on right.
Protecting flowers after pollination is important. The method
Generally used is to tie a glassine or paper bag over the end of the branch
earing the pollinated flowers (fig. 3). Sometimes two or three
flowers may be enclosed in a single bag. With some of the stone
670
YEARBOOK, 193 7
fruits, particularly the peach, this method has not been entirely
satisfactory, especially where the breeding work is done in the orchard.
The relatively long style or stalk of the pistil is easily broken if the
bag blows against it (fig. 4) causing loss in bagged flowers. It is
necessary, however, to use some method of protection where only a
Figure 3. — When only a few blossoms on the tree are to be pollinated it is necessary to
protect the flower from foreign pollen. A heavy paper bag or some cover not easily
collapsed by the weather is necessary to prevent injury to the pistil.
few flowers on a tree are pollinated. A very heavy grade of paper bag
with sufficiently sturdy basal folds to hold the sides out from the flower
when the bag is inverted over the branch and tied is desirable to
reduce the injury to a minimum. When large numbers of crosses arc
made, and when no special genetic or cytological studies are under-
taken, it is doubtful whether peach flowers need to be protected,
particularly if an entire branch or tree has been emasculated. Bees
or other insects in visiting the emasculated flowers rarely touch the
STONE FRUITS
671
M^
stigmas and thus do not introduce foreign pollen. If an entire tree
is emasculated for a large number of crosses, a tent built over the tree
will prove satisfactory not only as a means of protection for the emas-
culated flowers but for insuring a large set of fruit under unfavorable
weather conditions.
After fertilization of the ovules has taken place (fig. 5) and the style
begins to darken and wither, the protecting paper bag is removed and
an open-mesh bag of coarse
cheesecloth or heavy net is
E laced over the end of the
ranch to protect the devel-
oping fruit. If the fruit drops
off at maturity it will be held
in the bag. Where the entire
tree has been emasculated and
tented, or where a number of
branches on the tree have
been pollinated without bag-
ging, it is necessary to harvest
the fruits before they fall.
The stones are removed
from the harvested fruit and
are allowed to dry in a place
free from molds and fungus
contamination. Seeds of stone
fruits require an after-ripening
period of 2 to 3 months at
low temperatures before they
will grow. They are usually
soaked for several hours and
then placed in moist sand out
of doors during the winter, or, preferably, they may be held for 2 or 3
months in a refrigerator or cold storage at about 40° F.
To insure a high percentage of seedlings in the case of valuable
material, the best method is to remove the pits from the cold box,
crack them, and remove the seeds. The seed coats are then removed
and the young embryos sterilized in hypochlorite solution or some sim-
ilar disinfectant and placed in small bottles on sterile nutrient agar to
grow. When the young seedlings are rooted and a few inches tall,
they may be transplanted from the culture bottles to pots in the green-
house and later removed to the field or nursery row. The more
common method of growing the seed is not to remove the seed coat
but to plant the seed directly in pots in the greenhouse or in the
nursery. Sometimes the pits are not cracked but are planted directly
in the field in the fall when out-of-door temperatures will bring about
the proper chilling required to insure growth of the seeds in the
spring.
A great obstacle in stone-fruit breeding is the difficulty in getting
the seeds of some crosses to resume growth. Many hundreds of seeds
of crosses of sweet cherry, early-ripening varieties of peach, and other
stone fruits have been planted, but no seedlings grew from apparently
normal seeds. It is believed that planting the seeds on sterile nutrient
Figure 4. — A peach flower after fertilization,
showing the pistil with its long style and the
enlarging hairy hasal portion, the ovary, which
becomes the fruit. In the cherry, plum, apri-
cot, and nectarine the fruit develops similarly
from a single hairless ovary.
672
YEARBOOK, 1937
agar will be helpful. At the present time, however, there are stub-
born seeds of early-ripening varieties of peach and cherry that will not
grow even though given the agar-culture treatment. Many such
varieties possess desirable characteristics, but they cannot be used as
female parents until some method is found to obtain germination of
the apparently normal seed they produce.
To economize space the young seedlings are usually planted in test
blocks in rows 10 feet apart, with the trees 5 feet apart in the row,
which is about as close as cultural operations will permit. At least
Figure 5. — Peach flowers after emasculation and fertilization. The single pistil (A)
is normal, hut occasionally, in some varieties and under certain nutritional conditions,
two (B) or more pistils (C) may develop in a single flower.
3 or possibly 4 years must elapse before fruit characters can be studied.
If it is decidecl to hasten the fruiting of the progeny, buds or scions
can be taken from the seedlings when they are large enough and
grafted into branches of bearing trees. In general, budding has proved
a more satisfactory method for top-working peach than grafting. In
California, however, grafting has proved very satisfactory in the hands
of experienced men when dormant scions were placed early in the
spring in the cut-back branches of trees 4 to 8 years old. Fruit may
be obtained in 2 years from budding, and sometimes in 1 year from
grafts. Where tree characters of the seedlings are to be studied, this
information is best obtained by leaving them in the field for some
years after first fruiting.
Under the most favorable conditions it requires about 5 years from
the time the cross is made until a preliminary reading is obtained
from the seedling and trees can be propagated for testing in the orchard.
If we assume the average life of a peach tree to be about 15 years,
then it will be about 20 years before full evaluation can be made of
the lifetime merits of a variety. Frequently a much longer time
elapses before the value is determined, because of the fact that new
varieties are not tested promptly under widely varying soil and
climatic conditions.
STONE FRUITS 673
PEACHES
Early History
The original home of the peach {Amygdalus persica L. or Prunus
persica Batsch.) was thought to be Persia, since this fruit was doubt-
less introduced into Greece from that country shortly after the begin-
ning of the Christian Era. De Candolle concludes, however, that the
peach has never been truly wild in Persia. Botanists agree that the
peach is wild in China. The late Frank N. Meyer, explorer of the
United States Department of Agriculture, reported finding many wild
peaches in China, the fruits of which are inedible, being small and
hairy, hard, and with a sourish flesh {17)? The peach has also long
been cultivated in China. It was written about some 2,000 years
before its introduction to the Roman world. Reference to the "tao",
meaning peach, has been found in the writings of Confucius in the
fifth century B. C. and in the Ritual in the tenth century B. C.
There is evidence that the peach reached France and possibly Spain
at about the time it was introduced into Greece. From southern
Europe it spread to northern Europe, possibly the greatest spread
taking place from France. In more recent times France has been an
important nursery center, and in the fifteenth and sixteenth centuries
nursery trees were sent from France and disseminated through Eng-
land, Belgium, the Netherlands, and Germany.
Few other fruits are grown under such varied conditions and over
such extended areas as the peach. Once a wild inhabitant of China,
it is now cultivated in every part of that vast country. Extensive
plantings of the peach occur in Turkistan and Persia. It is not sur-
prising, therefore, that early writers regarded Persia as the original
home of the peach, as is suggested by the species name persica later
given it. Peaches thrive in all parts of southern Europe and are grown
in sheltered places in the northern latitudes. In the United States
the peach found such congenial surroundings that it spread rapidly
and widely, leading botanists three centuries later to believe it was
native to this country. Today peach varieties are found growing in
practically every State of the Union. While the fruit is not grown
commercially in regions that are subject to low winter temperatures,
some varieties or seedlings are able to withstand the winter tempera-
tures in the colder parts of the country.
Because of the general distribution of the peach in Europe, Asia,
South Africa, Australia, South America, and the United States, there
has been a general selection of varieties best adapted to the various
regions and climatic conditions, as well as to the preferences of
consumers. Through this process of selection and hybridization
peach varieties with widely differing characteristics have been devel-
oped and propagated. Some of the wide differences are so marked
that botanists have been inclined to separate the peach into races
and, in a few instances, species.
American pomologists {25) in the past century tried to divide
peaches into four groups or races: (1) The Persian race, brought to
North America by the early settlers, best represented by varieties
! Italic numbers in parentheses refer to Literature Cited, p. 746.
674
YEARBOOK, 1937
of the Crawford group; (2) the north China or Chinese Cling race,
characterized by large fruits with tender skin and flesh, vigorous
tree growth, and abundant and regular bearing, and including such
Chinese varieties as Chinese Cling, Chinese Free, and later descend-
ants Belle and Elberta; (3) the south China race, sometimes called
Figure 6. — Shapes of different types of peaches that may be used in breeding: A,
Peento, or so-called saucer peach of the Gulf States; B, the honey peach of Florida and
Texas, represented by varieties such as Imperial and Hooey; C, peach of the Chinese
Cling type, representing most of our present-day commercial freestone and canning
cling varieties.
the Honey, represented by varieties that bear small, oval to pointed,
white-fleshed fruits with a peculiar honey-sweet flavor, and adapted
in the United States only to some subtropical sections; (4) the Peento
race, a warm-climate type with trees inclined to be evergreen and to
bear fruits that are much flattened endwise, white-skinned and white-
fleshed, and sweet to very sweet. However, all varieties hybridize
STONE FRUITS 675
freely, and there has been so much crossing between the groups that
it is practically impossible to classify many of our present yellow-
and white-fleshed varieties on this basis (16) (fig. 6).
The nectarine was formerly thought to be a different species from
the peach. It is now known that the nectarine is simply a smooth-
figure 7. — The beginning of commercial peach growing. The early settlers planted
fruit trees near the homestead. The home orchard frequently gave place to large
commercial plantings.
skin peach. The trees differ in no respect from the peach, and it is
impossible to tell a peach tree from a nectarine tree. The leaves are
the same. The fruits and seeds have essential characteristics in
common. In short, the only difference between the peach and the
nectarine is the absence of hairs in the latter. Nectarines are known
to have come from peach seeds, and vice versa.
Commercial Peach Growing and Its Stimulus to
Variety Improvement
Commercial peach growing in the United States began early in
the nineteenth century (fig. 7). Large orchards were planted in
Maryland, Delaware, and New Jersey. Prior to this time thousands
of peach trees, all seedlings, were planted by growers. Many of the
varieties grown in those early years were apparently better suited
for making brandy than for general consumption as canned or fresh
fruit. While the art of budding and grafting had been known for a
long time, it was not until early in the nineteenth century that large
commercial orchards of varieties propagated from clons were used.
Table 1. — Fifty varieties of peach grown commercially in the United States during the past 25 years
Variety
Plaee of origin
Date of
origin
Originator or introducer
Color of flesh
Firmness of
flesh'
Stone, free
or cling
Ripening date '
Quality
Admiral Dewey . .
1899
1899
1897
1870
1912
1889
1880
1880
1845 (?)
1850
1886
1870
1820 (?)
1908
1906
1870
1875
1870
1857
1895
1913
Unknown
1891
1850
1760-70(?)
1886
1910
1890
1912
1869
1895
1815(?)
1885
1876
1882
Unknown
1851
1835
1890
J. D. Husted .
Yellow
White
Soft-melting—
do
Semifree
do
Semicling. . _
Free ~
do
Semifree
Free
do
do
July 15-23
Aug. 3-10
Early . ..-
Good.
Do.
C.P. Orr
do
Belle
White
Yellow .
White
Melting
do
Soft-melting—
Melting.
Soft-melting__„
Aug. 10-20
Aug. 29-Sept. 1 _
July 31-Aug. 5_ .
Late midseason.
Aug. 17-22
Sept. 8-12
Aug. 25-29
Late
J. P. Berckmans
J. W. Steubenraueh
Do.
Do.
Anne Arundel County, Mel...
Yellow
White
Excellent.
I.O.Hubbard
Do.
Chili . . -
Chili, N. Y
Yellow
White
.... do
Fair.
Imported by Charles Down-
ing.
G. L. Taber .
do
Soft-melting—
Melting ..
do
do
Nonmelting—
Melting .
do
Soft-melting—
Melting
do
Nonmelt«ng___
Melting
Soft-melting-..
do
Cling.
Semifree
Free
do
do.
Cling
Free
do
Semifree
Free
do
Cling
Free
Cling
Semifree
Cling
Free
do
do
Good.
Do.
Billerica, Mass -. ..
Yellow
do.—— .
do
White
Yellow
do
White -
Late midseason.
Aug. 17-20
Midseason
July 11-20
Aug. 21-27
Aug. 24-Sept. S.-
July 27-Aug. 5__
Late midseason-
Sept. 3-8
Late midseason _
Sept. 8-10
July 13-18
July 23-28
Sept. 22-27
Aug. 8-14_
Aug. 17-25 _
Sept. 21-25-
Aug. 23-30
Aug. 8-31-Sept.
3.
Sept. 23-27. ...
Sept. 5-9
Sept. 12-19
Medium early...
Late midseason _
June 19-30
Aug. 16-19
Sept. 3-8
Aug. 19-25
Do.
William Crawford
Sumner Gleason, Stark Bros.
Nursery.
Very good.
Early Elberta.
Good.
Fair.
S. H. Rumph
Good.
C. C. Engle
Do.
Do.
Fostbr
Medford, Mass
J.T.Foster
Yellow
do....
-.„do
L. T. Sanders-
Good.
Do.
George W. Griffin
_..do
Do.
W. G.Balsey
White
Do.
Hale Early .
Ohio -.
Mr. Moas. Introduced by
Hale and Jewett Nursery.
Unknown. ___ . ..
Eugene Hiley. .
E. H. Riehl.,
do
Do.
Heath Cling _.
Unknown. .
Marsriallville, Ga
North Alton, 111
do..
do
do
„..do
Melting
do
do
do
Do.
lliley
Very good.
Do.
Fair to good
J.H.Hale
South Glastonbury, Conn-
J. H. Hale, W. P. Stark.
J. N. Stearns
Mr. Krummel...
Yellow .-
do -
do—.
. .do
Firm-melting..
Melting
do
do — .
do -
do
do
Soft-melting— _
Melting.
do
do -
do
do _.
do
do
do
Semifree
Free.
Cling.. ...
Free
do
do
Good.
Do.
Do.
Ohio
Unknown __
J. W. Steubenraueh __
G. W. Thissell
do.
White-
Yellow
White
do
do
Yellow
Good.
Mexia, Tex.. ..
Do.
Do.
Mountain Rose.
Morristown, N. J
Dr. Marvin _ . _
Sir John Oldmixon
G. W. Thissell
Good.
Do.
John Muir farm, Silveyville,
Calif.
Do.
- J
3
las
to
©
©
Pallas
Peento—
Phillips—
Paloro
Prolific
Rochester
St. John
Salwey
Stump _._
Triumph
Tuskena (Tuscan)
Augusta, Qa _..
China
Sutter County, Calif,
Gridley, Calif
Michigan
Rochester, N. Y
Unknown.
Surrey, England
New Jersey
Vineyard, Ga
Mississippi
1878
1828
1880
1912
1890
1900
. 1860(?)
1844
1825
1895
1873
L. E. Berckmans- __
William Prince
Joseph Phillips
Frank Dixon
Greening Bros
Heberle Bros
Unknown
Colonel Salwey_-_
Unknown..
J. T. Husted
Unknown
White..
do-
Yellow.
do-
do-
do..
do._
do-
White—
Yellow..
do...
.....do
do
Nonmelting.
do..
Melting
do
.....do
.-..do
do
.—do
Nonmelting..
do_
do-
Cling. .
.do-
Free-
do—.
do—
do—
do— _
Semifree.
Cling
Aug. 22-26
Medium early
Sept. 12-19
Aug. 22-26
Aug.25-Sept. 1__
July30-Aug.5„_
Aug. 5-10
Late
Sept. 3-8
July 15-27
Early midseason
Do.
Do.
Do.
Do.
Do.
Excellent.
Do.
Good.
Very good.
Good.
Do.
i The terms "melting" and "nonmelting" are used to denote the degree of softness of the flesh of ripe fruits. All freestones have either firm- or soft-melting flesh, and some early-
ripening clingstones (Greensboro) have soft, watery, melting flesh, while the flesh of clingstone varieties of the commercial canning type, such as Phillips, have firm nonmelting flesh.
• The ripening dates are those for the U. S. Department of Agriculture orchard at Beltsville, Md„ in 1936, a normal season. Where the variety listed did not fruit, the general
season is indicated as early or midseason.
Co
O
fcq
3
CO
C7\
678 YEARBOOK, 1937
As the commercial industry spread, there was always a demand
for varieties that would succeed best under various soil, climatic, and
other environmental conditions occurring in the different peach-
growing sections. In northern regions growers were interested in
varieties hardy in wood and bud to withstand low winter temperatures,
while in the more southern latitudes they were interested in varieties
that would stand summer droughts and high temperatures and with
fruit that would retain its firmness during shipment to distant mar-
kets. Then came the scourge of disease and insect troubles — peach
yellows, leaf curl, brown rot, curculio, and the peach-tree borer. What
varieties, if any, would prove most resistant to these troubles?
During the period 1850 to 1900 a large number of varieties were
selected from seedlings as worthy of introduction. The list of 50
varieties given in table 1 contains the names of many that still have
an important place in the peach sections of the country. They also
served as parents for varieties introduced during the last 20 years.
The dates of origin of these varieties cannot be accurately obtained
in all cases. They are approximately correct and are given to show
the length of time the variety has been under orchard test.
It will be noted that the geographical origins of these varieties
include nearly all of the States east of the Mississippi between the
Great Lakes and the Gulf. Peach growing as an industry was truly
widespread in the United States by the end of the nineteenth century.
The need for new varieties to replace those that had been under trial
was apparent during the period from 1900 to 1910. This was prin-
cipally due to the fact that peach growing was rapidly developing into
an industry for specialists. When the business of peach growing had
developed to a point where it was necessary to ship the crop to con-
suming markets several hundred miles from the orchards, varieties
had to be chosen that would stand up in transit and compete success-
fully with varieties from other sections on the market at the same time.
The freeze of 1899 had wiped out many orchards in the North and
emphasized the need for varieties that would withstand cold for the
commercial orchards of the future. More recent freezes of the
winters of 1917-18, 1933-34, and 1935-36 have reemphasized the
importance of developing varieties for the North that are more
cold-resistant than many now being grown.
Work of Private Breeders in the United States
During the last 30 years there has been an increasing recognition
by peach growers of the need of originating new varieties better
adapted to meet local requirements in various regions. This is well
illustrated by the more recent work of J. W. Steubenrauch, of Mexia,
Tex., who developed the Carman variety from pits planted in 1889.
It is one of many important commercial peach varieties originated in
Texas during the period 1850-1900. Mr. Steubenrauch, now 84 years
old, summarized his work in a letter on May 13, 1936.
He planted his first orchard of peaches in central Texas in 1879.
There were many kinds available to the growers, mostly what were
then called Indian peaches, some good, but not very suitable for general
markets. Recognizing the need for varieties of the best quality
ripening from early to late season, he bought many trees of new
STONE FRUITS 679
varieties from various parts of the country. In the course of a few
5 [ears he had 100 or more distinct varieties growing in his orchard,
h'om this number there were not more than about 10 that would be
called good varieties for that period, mostly suitable for home use.
Among a lot of Elberta trees planted in 1884, he found one tree that
he considered superior to all the rest, producing finer fruit more
regularly. Having a fine later peach that was part Indian stock,
named Belle October, he decided to bud from the fine Elberta and
Belle October parents on a single stock away from all other peach
trees. From the two varieties blooming together with bees as pollinat-
ing agents, he obtained fruit and seeds of the early and late varieties.
Planting the seeds from the best peaches of both varieties, he
produced some fine new seedlings in season from the time of Elberta
till late in October. One of the leading ones is the Frank, which was
named for Frank P. Holland, publisher of Farm and Ranch. This
peach bore a heavy crop again in 1936, making 32 years of continuous
annual production. Mr. Steubenrauch describes this variety as a
fine yellow-red cling, ripening in the middle of August in central Texas.
In addition to the Frank he produced six others that he considers
fully as good. These are Tena, Lizzie, Liberty, Anne, Barbara,
and Katie.
These varieties, which have been tested in southern latitudes as
well as in some of the Northern States, have demonstrated superior
germ plasm and are worthy of note for possible use by breeders
of peaches.
The man who discovered and introduced the variety that took the
lead in commercial peach production in this country from 1910 up to
the present was the late S. H. Rumph. He produced the Elberta
from a seed of Chinese Cling planted at Marshallville, Ga., in 1870.
Curiously enough, another seed reported to have come from the same
Chinese Cling tree, planted in the same year by S. H. Rumph's brother,
L. A. Rumph, also of Marshallville, Ga., gave rise to the variety called
Belle of Georgia. Today these two are still among the leading com-
mercial varieties. They are of particular genetic interest because
the Elberta, a yellow, and the Belle, a white, are reported to have come
from seeds of the white-flesh Chinese Cling, and because they are
promising varieties for use as parents in breeding work.
Hiley, a probable seedling of Belle, originated with Eugene Hiley,
also of Marshallville, Ga., in 1886. Today the Hiley Variety ranks
second to Elberta as the leading peach of the Southeastern States.
It has demonstrated its value as a possible parent in peach improve-
ment because of its high quality and its ability to produce fruits in
those southern latitudes where warm winters may be a factor in
delaying spring growth and blossoming (fig. 8).
One of the most important varieties that became prominent in the
period 1900-1920 is J. H. Hale. This variety was discovered by
J. H. Hale as a single tree in a lot of Early Rivers peaches shipped
to him by David Baird, of Manalapan, N. J., and planted on his farm
at South Glastonbury, Conn. Buds from this tree were taken later
to Hale's farm at Fort Valley, Ga. Here the variety also showed
great promise as a commercial peach, and it was introduced by Hale
through the W. P. Stark Nursery in 1912. By 1925 it ranked fourth
680
YEARBOOK, 193 7
among the freestone varieties grown for fresh fruit in the United
States. Present opinions differ as to its value as a commercial variety.
It has most of the essential fruit characters of a good commercial
peach, but the trees are somewhat dwarfish on some sites and locations,
not particularly hardy in wood and bud, and not highly productive.
The flowers are pollen-sterile, a serious fault that affects productivity
when the variety is planted in solid blocks. By and largo, the variety
Figure 8. — In southern peach-growing latitudes and in regions with warm winters some
varieties are much slower than others in coming out of the rest period after mild winters.
On the left is a row of Hiley in full bloom, and on the right a row of Early Rose still
dormant. Photographed at Marshallville, Ga., April 12, 1932, a year of marked pro-
longed dormancy for this region. This is about 5 weeks later than average full bloom.
is not as widely adapted nor as productive as one of its probable
parents, the Elberta, and it has not displaced that variety from the
position of America's no. 1 commercial peach. However, certain
characteristics of the J. H. Hale make it of particular interest to the
peach breeder and cytologist. Some genetic features of this variety
are discussed later in this article.
Hale introduced another variety, the Early Rose, which proved its
commercial importance as an early shipping peach for the Southern
States. This soft-flesh cling of fair quality and good color was
discovered as a chance seedling growing at Fort Valley, Ga., by John
H. Baird, of the Hale farm.
Controlled crossing has been carried on by J. E. Markham, of
Xenia, 111., who, beginning in 1925, developed and introduced to the
trade Vivid Globe (Yellow Globe X J. H. Hale), Canadian Queen
STONE FRUITS 681
(Canadian Banner X Early Elberta), Markberta (Halberta X
Canadian Queen), Markham Cling (Golden Cling X Jap Cling),
Mark Late (Canadian Queen X Markberta), Globe Haven (South
Haven X Vivid Globe), Markham Jewel (Imperial Elberta X
Canadian Queen), and Halberta (J. H. Hale X yellow seedling).
Most of these varieties have not been widely tested.
Private breeders played a very important part in the work of
selecting peach varieties of promise not only from a commercial stand-
point but also from that of further improvement of the peach by
systematic breeding. Space does not permit listing the many in-
dividuals who have been constantly on the watch for the appearance
of superior sorts originating as chance seedlings and who subjected
the seedlings to careful test. The names of many of these men are
given in table 1, together with the description of the varieties they
introduced.
Peach Breeding at Public Institutions in the United States
Breeding work with peaches was started at the New York (State)
Agricultural Experiment Station at Geneva, N. Y., in 1895, when
open-pollinated seeds of the Elberta were planted. No crosses were
made until 1910. Work was also begun at the Iowa ' Agricultural
Experiment Station in 1905, when the late S. A. Beach planted some
selfed seeds of the Chili in an attempt to develop hardy varieties
that would prove resistant to cold. Crandall, at the Illinois station,
began work on the development of new varieties about 1907. At the
same time work was started at the California station on the develop-
ment of peach varieties that would be satisfactory for growing in the
warm climate of southern California. By 1914 several States had
provided funds for peach breeding at a number of State institutions.
Peach-breeding studies were begun at the New Jersey station in
1914. The present peach-breeding work in Michigan started at the
South Haven Horticultural Experiment Station in 1924. The
United States Department of Agriculture began cooperation in peach
breeding with this State in 1919 and later cooperated in the work
in California. By 1930 there was considerable interest in develop-
ing new varieties of peaches by systematic breeding, and variety
improvement work has recently been started in a number of other
States.
The first promising varieties that resulted from this early station
work for replacement of unsatisfactory kinds were introduced in
1925 by the New Jersey station and also by the Horticultural Experi-
ment Station at Vineland, Ontario, Canada. A list of new varieties
introduced as a result of systematic breeding and selection work
by State and Federal agencies and by the Ontario station for the
period 1900-36 is given in table 2.
Work is now being carried on at the various State experiment sta-
tions to meet special requirements of the peach industry in the several
States. Following table 2 is a summary of the crosses being made
and the progeny obtained, beginning with States in which the work
has been in progress for the longest time.
138004°— 37 44
682 YEARBOOK, 1937
Table 2. — Peach varieties developed and introduced by public institutions
State or Province
California..
Iowa
Michigan...
New Jersey,
V. S. Department
of Agriculture.
Ontario, Canada.
Variety intro-
duced
]!al)cock
Polly
Halehaven
Ambergem
Cumberland...
Buttercup
Delicious
Kelipse
Goldfinch
Golden Jubilee.
Marigold
Massasoit
Meteor
Oriole
Pioneer.
Primrose
Radiance
Rosebud.
Sunbeam .
White Hale...
Garden State..
Maxine
Leeton...
Stanford
Ellis
Vaughan
Vedette
Veteran
Valiant
Vimy
Viceroy
Parentage
Strawberry X Peento. .
Chili (selfed, Ft open-
pollinated) .
J. H. Jiale X South
Haven
Belle (selfed).
Belle X Greensboro
Lola X Arp
Belle X Greensboro
Belle (selfed)
Slappey X Admiral
Dewey.
Elberta X Greensboro
(open-pollinated hy-
brid).
Lola X Arp
Slappey X Admiral
Dewey.
Belle (selfed)
Slappey X Admiral
Dewey.
Belle X Greensboro
Belle X Elberta
Belle X Greensboro
Carman X Slappey
Slappey X Admiral
Dewey.
J. II. Hale X Belle or
Ray.
Seedling nectarine (self-
pollinated) .
No. 1 Early seedling X
Lemon Free.
Leader (open-pollinated)
llauss X Phillips
Phillips X Linden
Leamington (selfed)
Elberta (open-polli-
nated).
Vaughan X Early El-
berta.
Elberta (open-polli-
nated).
Elberta X Arp
Vaughan X Early El-
berta.
Breeder
Citrus Experiment
Station, E. B. Bab-
cock and O. O.
Smith.
Iowa Agricultural Ex-
periment Station.
South Haven Horti-
cultural Experiment
Station.
New Jersey Agricul-
tural Experiment
Station.
do
do
do.
do
do
.do.
.do.
.do.
_do.
.do_
.do.
New Jersey Agricul-
tural Experiment
Station.
do
do
do
New Jersey Agricul-
tural Experiment
Station.
W. F. Wight
.do.
.do.,
.do.
Ontario Horticultural
Experiment Station.
do
.do..
.do..
.do.,
.do..
When
crossed
1907
1915
1924
1914
1910
1914
1914
1918
1914
1910
1910
1914
1910
1915
1915
1914
1910
1910
1919
1924
1924
1924
1913
1915
1919
1917
1910
1919
Year
named
and
intro-
duced
1933
1932
1932
1925
1925
1925
1925
1920
1925
1925
1925
1925
1925
1925
1925
1925
1925
1925
1935
1935
1935
1935
1925
1925
1928
1925
1925
1930
New York
To date 65 varieties, 8 seedlings, and 5 P. I.3 numbers have been
used in breeding work at the Agricultural Experiment Station at
Geneva. Champion was used 8 times, Crosby 8, Elberta 27, Greens-
boro 13, Chili 11, Hunter (nectarine) 19, J. IT. Hale 11, Krummel 8,
Livingston 12, Rivers Orange (nectarine) 10, Rochester 10, South
Haven 10, Sure Crop (nectarine) 31, and Veteran 9. There were in
all 333 crosses, 24 selfs, and 13 open pollinations. Of the 400 seed-
3 Trees imported by the Division of Foreign Plant Introduction as well as seedlings grown from seeds
brought in are distributeil for testing under numbers preceded by the initials P. I.
STONE FRUITS 683
lings set in the orchard, 307 have originated from crosses made since
1922. Many of the seedlings are just beginning to fruit, and there-
fore their full history is unknown.
New Jersey
From the work started in 1914, 20 new varieties had been introduced
up to the spring of 1936. In addition to these there are 17 unnamed
but specially selected peach seedlings showing considerable promise
that are now being grown in State-wide commercial tests During
the period 1923 to 1936, 6,257 seedlings had been obtained by crossing,
selling, and open-pollinating varieties of peach and nectarine possess-
ing desirable characteristics. Of this number 1,064 have been re-
tained for further study. Approximately two-thirds of this number
are of J. H. Halo parentage. ,
One of the objectives of the breeding work at the Iowa Agricultural
Experiment Station is to test the feasibility of making interspecific
crosses with stone fruits. About 100 potted trees grown in the green-
house are being utilized in this work. Varieties of Amygdalus persica,
including nectarines of A. davidiana (Carr.) Zabel as well as hybrids
between these two species, are being grown. From the crosses made,
approximately 75 promising seedlings are now being studied in the
field. These include Chili (fourth generation) open-pollinated, Chili
(third generation), Bailey X A. davidiana, J. H. Hale X A. davidiana,
and Chili (third generation) X A. davidiana.
Illinois
Of the first series of crosses made by Crandall at the Illinois station
all have been discarded except Illinois 146, 148, and 101. These are
being propagated for further testing under semicommercial conditions.
The quality of all three of these is high, but they probably are some-
what lacking in the firmness of flesh that a commercial peach must
possess. .,. , .
Michigan
From the peach-breeding work begun at the Michigan station in
1924, one promising commercial variety, Hale Haven, a cross of J. H.
Hale X South Haven, was introduced in 1932. This is a large yellow
freestone maturing 17 days before Elberta and about the same time
as South Haven. It is considered to be an improvement over the
latter variety because of its higher color, thicker skin, and perfect
freestone condition. The number of seedlings being grown at the
present time from the crosses made during the period 1924-36 is
2,076. During the period 1924-30, 700 seedlings were obtained from
crosses of J. H. Hale with a number of commercial varieties important
in Michigan, such as Banner, Kalamazoo, Elberta, South Haven,
and New Prolific. Of this list only 15 had superior horticultural
value.
Work is now under way in an attempt to develop some clingstone
varieties of canning types suitable for Michigan conditions. At the
present time there are under observation 359 seedlings from crosses
where one parent is freestone and the other cling, or where both
parents are cling.
684 YEARBOOK, 1937
California
The work on peach breeding at the California Agricultural Experi-
ment Station at Davis has been confined in recent years (1930-36)
largely to developing a satisfactory type of nectarine for canning.
A large number of seedlings are now being grown on the station
grounds from about 1,310 crosses of nectarine X nectarine and
nectarine X peach. Among the varieties of nectarines used as seed
and pollen parents are Stanwick, Ansenne, Diamond Jubilee, Sure
Crop, Quetta, Boston, Dixie, Now Boy, Goldmine, and Lippiatt.
Peach varieties used either as seed or pollen parents in crosses with
these nectarine varieties are Lovell, Muir, Late Champion, Red
Cling, Elberta, Late Crawford, J. H. Hale, Fay Elberta, and Rochester.
In addition there is a very excellent collection of over 300 named and
P. I. numbered varieties of peach and nectarine as a source of breeding
material.
Breeding work with peaches was begun in 1907 at the University of-
California Citrus Experiment Station, Riverside, to develop varieties
for growing in southern California. In this section many of the older
varieties of cling and freestone types do not start growth sufficiently
early in the spring to secure normal development, and shedding of
blossom buds is common following warm winters. The Babcock
peach, which was introduced in 1933 by G. P. Weldon, of the Chaffee
Junior College, and by the University of California, was the result of
the early work started by E. B. Babcock and C. O. Smith and con-
tinued by J. W. Lesley. The special value of the Babcock peach lies
in its easily broken dormancy. It is an early white freestone of fair
size and good quality. In recent years other crosses have been made,
using as seed parents various cling and freestone varieties, and pollen
from Honey and Peento types and varieties in which dormancy is
easily broken. The Babcock is also being used in these crosses. From
this work about 12 seedlings have shown promise and are being
carried for further testing. Sims pollinated by P. I. 32374 has given
a very promising yellow cling. Sims is a variety characterized by a
short rest period. ., ,
Massachusetts
Breeding work at the Massachusetts station was begun in 1918.
The progeny from most of the crosses made in 1925 and 1926, using
as female parents varieties that showed considerable hardiness, has
been discarded as unsatisfactory for growth under Massachusetts
climatic conditions. There are 2,460 seedlings now receiving special
study, mostly of a genetic rather than an immediately practical
nature. However, a number of promising seedlings have been
selected for further testing. In 1931 and 1932 over 2,000 seedlings
were obtained in crosses with Belle, Champion, and Gold Drop in
studying the problem of linkage between flesh adherence to stone and
flesh texture. Some crosses have also been made in a study of the
inheritance of bark color. Tr. . .
Virginia
In recent years studies have been made on the progeny of a smooth-
skinned Crawford seedling obtained by selfing, when it was crossed
with such varieties as J. H. Hale, South Haven, Rochester, Oriole,
Golden Jubilee, Elberta, and Gold Drop. The object of the crosses
STONE FRUITS 685
is to obtain a variety of high quality possessing bud hardiness. Or-
chard and potted trees are being used. From this work, as well as
that previously done with open-pollinated and selfed Elberta, about
15 seedlings of horticultural value have been obtained.
Texas
Breeding studies were begun at the Texas Agricultural Experi-
ment Station, College Station, Tex., in 1935. This work has for its
purpose the development of varieties suited to peach-growing dis-
tricts of Texas where the winter temperatures may not be low enough
to give the proper amount of chilling required for best development
of varieties that do better in more northern latitudes. Hiley, Pallas,
Belle, Early Elberta, Anna, Indian Free, Slappey, and Florida Gem
have been used in the crosses.
United States Department of Agriculture
Peach-breeding work in the Department was started in 1919. The
early crosses were made at the branch experiment station of the
Michigan Agricultural College at South Haven, Mich. Later, crosses
were made at the United States Plant Introduction Garden at Chico,
Calif. Since 1922 the work has been carried on in the Santa Clara
Valley, principally in the experimental orchard at Leland Stanford
Junior University, Palo Alto, Calif. Work has recently been undertaken
at the United States Horticultural Station at the National Agricul-
tural Research Center, Beltsville, Md., where some 150 varieties are
available for study. During the past year 79 separate crosses were
made, usually high-quality cold-resistant varieties.
New varieties that have been introduced as a result of the work in
California are Leeton, Maxine, Stanford, and Ellis. The Leeton is a
selected seedling of Leader grown at Palo Alto from pits imported by
Frank Dixon from Leeton, Australia. Maxine is the product of a
cross made at South Haven, Mich., between Lemon Free and an
unnamed early-ripening seedling of noticeable bud hardiness. The
Stanford, a Hauss X Phillips hybrid, is a canning cling peach ripening
in season with Phillips. The Ellis, a cross of Phillips X Linden, is also
a canning cling type ripening about a week ahead of Stanford. The
introduction of these varieties has been based largely upon their
behavior under California conditions. The two freestone varieties
are worthy of testing under eastern conditions. The Leeton ripens
about in season with Triumph and shows promise of being a better
early peach than the latter variety. The Maxine is a yellow-flesh
variety of high quality, ripening just after Rochester. It has proved
to be quite cold-resistant in bud during two recent severe winters
(1934-35 and 1935-36) at Beltsville, Md.
A large number of hybrids have been produced since 1922, and these
are under test in the experimental orchard at Palo Alto, Calif. Some
of the more promising of these hybrids are being tested at other places
in California and, in a limited way, in a number of orchards in the
eastern United States. Nearly all of the imported freestone varieties
produced in this California breeding work are being tested at Belts-
ville, Md. The seed parents are given in the following list, together
with the number of hybrids developed from each parent: Elberta 11,
686 YEARBOOK, 1937
Hauss 5, Horton KiversXChili 8, J. H. Hale 11, Illinois 2, Leader 5,
Libbee 8, Lovell 7, Maxine 3, Miller Late 2, Mira 1, Muir 15, Newhall
3, Ontario 4, Paloro 18, Phillips 5, Pratt-Low 10, Salwey 44, Selma 3,
St. John 2, Tuskena 14, Uneeda 1, Yellow Free 2, Yellow Transvaal 18.
In addition to the more common commercial varieties, a large
number of Department introductions having desirable characteristics
and showing considerable promise for breeding have been used.
Among these are a Chinese introduction (P. I. 43289) and a Spanish
cling (P. I. 43570T2). The varieties listed above as female parents
have also been used as pollen parents in a good many reciprocal crosses.
Backcrosses and intercrosses have also been made with first-generation
hybrids. Studies are being made on the progeny of 234 separate and
distinct crosses of named varieties and hybrids. From this group of
hybrids a number of promising freestone varieties have been obtained
that have characteristics superior to a number of the present commer-
cial varieties. Some are promising canning clings, while others show
marked resistance to delayed foliation and are adapted for growing in
warmer climates where the present commercial varieties do not produce
satisfactory annual crops. Combinations have been made between
important commercial varieties subject to delay in foliation and such
introduced varieties as Yellow Transvaal and St. Helena, which have
less prolonged dormancy, in the hope of transmitting this desirable
character to the progeny.
In 1909 Shamel and associates (29) noted some striking limb varia-
tions in studies of freestone varieties in California, and more recently
he has discovered some early- and late-ripening strains among peach
varieties. Weldon (31) has also reported finding several limb varia-
tions in orchards in the same State. It appears that some varieties of
peach are less stable than others. While very few color sports of peach
have been found to date, it would not be surprising if more should be
found when careful search is made.
Peach Breeding in Other Countries
Canada
Since 1914 peach breeding has been carried on at the Ontario
Horticultural Experiment Station, Vineland, Ontario, to meet the
needs of the market and climatic conditions of southern Canada,
especially to secure varieties giving a seasonal succession of ripening.
Open-pollinated seedlings have been grown in considerable numbers.
Some hybridizing has also been done. Earlier ripening Elberta types
with attractive fruit of high quality were sought. In all, 13,106 seed-
lings were grown during the period 1911-36. Of these, 144 have
horticultural value. Six varieties were introduced during the period
1925-30. Two of the most promising, Valiant and Vedette, are
Elberta seedlings.
From 1918 to 1922 approximately 2,200 open-pollinated seedlings
of Elberta were fruited. A second lot of 1,000 Elberta seedlings bore
a marked resemblance to the parent tree in growth characteristics
and in fruit. Probably 15 to 20 percent could have been propagated
and distributed as Elberta, while approximately 3 percent had white
flesh, and 15 percent were semiclings or clings. A fair number were
STONE FRUITS 687
moderately good, none exceptional, the majority being of Elberta
quality or poorer. The variation in season from Elberta was slight,
ranging from a week earlier to a week later. Five hundred and fifty
open-pollinated seedlings of Lemon Free were almost identical with
the parent. Only a very occasional tree bore fruit with even a sug-
gestion of color other than the yellow. Seedlings of New Prolific,
Reeves, and Early Crawford were very much like their parents. The
fact that open-pollinated seedlings of peach came so true to type when
the pits were taken from an orchard in which there were upward of
150 varieties, thus affording every opportunity for natural crossing,
suggests that the peach is usually self-pollinated under orchard
conditions. „ , ,
England
Experiments with peaches and nectarines were begun at the John
Innes Horticultural Institution, Merton, England, in 1911. The ob-
ject was to investigate the genetic composition of fruit trees by raising
selfed offspring. The varieties used were Royal George, Blood Leaf,
and Lord Napier nectarine. The results obtained will be considered
later under the discussion of genetic relationships in the peach.
Australia
The work on production of improved varieties of dessert peaches in
New South Wales is located at Hawkesbury Agricultural College,
Richmond, while that on improved varieties of canning peaches is at
the Yanco Experiment Farm, Yanco. Breeding at the Yanco Farm
with peaches was begun in 1928. One of the principal objectives was
the development of better varieties for canning that would possess
high quality, large size, good yield, and freedom from red around the
pit. There is a need for early canning varieties to come in imme-
diately after the late apricots are harvested. Table freestone types
are also sought. in New South Wales, though not specifically in the
breeding program at Yanco. The following varieties have been used
in crosses as sources of open-pollinated seeds: Golden Queen, Leader,
Paloro, Pullars, Sims, Tuskena, Goodman Choice, Locksley Perfec-
tion, and Phillips (Victorian strain). Of these the greatest promise
as parents has been shown by Golden Queen, Phillips, Tuskena, and
Sims (Victorian). Goodman Choice has desirable habits, and Pullars
excels in yield but is red around the pit. Leader, a freestone, is* one
of the best parents. Dessert types that are being planted for orchard
trial are Phillips X Triumph, Tuskena X Leader, and La France
X Elberta.
At the Hawkesbury Agricultural College, seedlings of Goldmine
(nectarine) X Triumph (peach), Blackburn X Triumph, and Elberta
X Wiggins have produced fruit of some promise as freestone dessert
peaches. With nectarines, work is under way to improve on the
standard variety Goldmine. The varieties used as pollen parents are
Mrs. Chisholm, W. C. Frip, and Irrewarra.
Morocco
A fruit and vegetable experimental laboratory was established in
1933 for the study of horticultural genetics. Its activities extend to
the six experiment stations of the Lacarelle group, distributed in the
688 YEARBOOK, 1937
different fruit-producing regions of Morocco, as well as to the official
experimental gardens of the protectorate. The peach-breeding work
has a definite objective, the production of new varieties of high
quality adapted to local elimatic and soil conditions, as well as stocks
resistant to certain diseases, such as gummosis. The work to date
has been concerned principally with the study of the hereditary
characters of varieties that would appear to be the best parents. A
number of hybrids have been produced and are under test. Four
forms of the Atlas peach are being used as stocks.
Some Objectives in Improvement of Peach Varieties
by Breeding
In surveying the long list of peach varieties available for planting,
many are found with very desirable characteristics but for one reason
or another not entirely satisfactory from the standpoint of the com-
mercial grower or the home fruit gardener. The fault is often deter-
mined by the fruit-growing region in which the particular variety is
grown. In one region it may be lack of resistance to winter cold, in
another it may be unproductiveness; in still another a peach may
prove to be a good bearer with satisfactory cold resistance but lack
fruit size and quality. If suitability for canning is the principal
requirement in a section, a variety must be judged entirely from this
standpoint. Varieties poorly suited for one region or purpose may be
entirely suitable for other conditions.
In this article the Elberta has been mentioned as our most important
commercial variety, but it lacks some desirable characteristics. It is
adapted to a wide range of soil and climatic conditions and is an
excellent shipping peach, but it does not have the high fruit quality
nor the desired degree of resistance of the tree and blossom buds to
low winter temperatures. Where the characteristics of this variety
have been combined by breeding with those of a variety more hardy
in bud, the results have been promising. A few varieties have been
obtained that are of higher quality and more cold resistant in bud than
Elberta, but they are not so widely adapted to the fruit-growing
regions of this country. Seedlings of the Elberta have been found
that ripen ahead of the parent and have fruit of higher quality and
more attractive in appearance. So far, when all characteristics are
considered, a peach truly better than Elberta has not been found;
but if by proper combination of characters a superior variety that
is as widely adapted can be produced, it will be a major contribution
to American fruit culture. To secure a hardy commercial variety
for the colder peach-growing sections of the United States is another
most important objective in fruit improvement.
It has long been known that varieties of the so-called Crawford
type are of very high quality but not especially productive, and very
tender in bud. Varieties of this type have passed out of commercial
production because they possessed these unprofitable characters.
Attempts should be made to introduce Crawford-type fruit quality
or its equal into other varieties, or to combine the hardiness and
Productive qualities of other varieties with those of the Crawford type,
rogress has been made in this direction by using St. John, a Crawford
STONE FRUITS 689
type of high quality but not particularly strong in tree character and
cold resistance in bud, in crosses with Admiral Dewey, an old variety
that is particularly hardy in bud, with small, fuzzy, unattractive
fruits. A very promising hybrid has been thus developed in the
breeding work of the Department of Agriculture.
The J. H. Hale variety has many outstanding fruit characteristics,
but it is lacking in vigor of tree, hardiness, and productivity. A
cross of J. H. Halo X South Haven at the Michigan Agricultural
Experiment Station has resulted in a hybrid showing decided improve-
ment over the South Haven variety. Considerable breeding is under
way, using the J. II. Hale variety as a parent. Accomplishments to
date, while not entirely satisfactory, give promise for the future.
Thb raw material represented by varieties of peach in this country
needs further reworking through breeding methods in order to obtain
the desired combination of characters. In this material there are
still many important characters lacking that may be found in
varieties now growing in other parts of the world. The need of con-
tinuing to import material is apparent. An example is the quest for a
variety that is not subject to delayed foliation. In climates with
warmer winters than those of the fruit regions of this country, varieties
are to be found adapted to such conditions. Such varieties should be
introduced into this country for combination with our own. Progress
has been made in California in recent years on this aspect of breeding
work by the Department of Agriculture. Varieties of the poach of the
St. Helena and Transvaal typos, introduced respectively from the
Island of St. Helena and from South Africa and crossed with our
native varieties, have given results that would indicate that the
problem of delayed foliation can bo overcome at least to some extent
through breeding.
There is need for more knowledge about the heritable characteristics
of rootstocks for poaches. It has boon observed that some varieties of
a particular parentage are more susceptible than others to cold injury
or to root disease. It is important to know which seedlings may be
used as stocks to insure longevity, productiveness, and disease resist-
ance. Work is now under way in the Department of Agriculture to
determine the merits of seedlings of known varieties of peach and plum
suitable for understocks (fig. 9).
As already indicated, methods must be devised whereby the seeds of
early -ripening varieties of stone fruits can be made to germinate after
crosses have boon made.
Another important objective in stone-fruit breeding work is the
development of superior varieties for canning and for drying. In
California at the present time varieties of apricots suitable for canning
are very much sought for. Varieties of peaches of the canning cling
type that have been used for a number of years are not entirely satis-
factory because of one weakness or another. Some otherwise satis-
factory varieties develop red color in the flesh, especially about the
pit, which renders them undesirable for canning. Pit splitting and
gumming are other faults. Some of the canning varieties used at the
present time are susceptible to mildew through the inheritance of
glandlcssness. Good typos lacking such objectionable characteristics
are needed for canning.
690
YEARBOOK, 193 7
The method of approach to the problem of developing better varie-
ties will involve basic studies in the inheritance and transmission of
characters. An important part of the work, therefore, will be growing
and studying progenies to determine the transmission of desirable as
well as undesirable characteristics.
Very little work has been done from the standpoint of securing
desirable characteristics through induced mutations. Polyploidy, or
increase in the number of chromosomes, which has proved of special
interest with other crops, has received little attention from workers in
Figure 9. — Peach rootslock effects. Early Hiley variety, fourth year in the orchard. The
row on the right is on plum (Prunus hortulana), and the one on the left is on the widely
used Tennessee "natural" peach stock. The dwarfing influence on the hortulana stock
is apparent.
stone-fruit breeding. Some work has been done at the New York
Agricultural Experiment Station at Geneva in an attempt to induce
polyploidy in stone fruits through the selection of large pollen grains.
This method has not yet yielded satisfactory results, but the studies
need to be continued, with many other attacks on the general problem.
No results have been obtained so far in attempts to cause mutations
through heat treatments, a method that seems promising in corn
breeding.
Some Genetic Facts Established in Peach Breeding 4
In a collection of 100 or more peach varieties selected at random,
the casual observer of the trees might think that they are all one variety.
Among peach varieties in general there are no very marked differences
in general tree characters. There are, however, distinct differences in
size, shape, and color of leaves, in time of blossoming, in color and size
of flower, in time of ripening, and in fruit characters. Genetic studies
« This section is written primarily for students and others technically interested in breeding or genetics.
STONE FRUITS 691
show these characters to be inherited, and in hybridization many of
them appear in the normal Mendelian ratios. Cytological studies to
date have not revealed how the factors governing these characters are
linked, nor where they are located on the chromosomes, nor what the
behavior is in the reduction division of the sex cells.
Connors (4, 6, 7), of New Jersey, was one of the first workers in
this country to investigate some of the genetic relationships in peaches.
He made crosses between some of the important commercial varieties
in an attempt to gather information on inheritance of characters.
Inheritance of Flesh Characters
Flesh color. — The parents used by Connors in one series of crosses
were Elberta and Early Crawford as yellow-flesh varieties, and Belle
and Greensboro as white-flesh varieties. Early Crawford has small
blossoms, Elberta medium, and Greensboro large. All are freestone
except Greensboro, which is a soft semicling. An analysis of the
progeny in the Fi generation showed some interesting facts. All of
the varieties used in the crosses were of unknown parentage, having
originated as chance seedlings. Belle, a white, and Elberta, a yellow,
are supposed to be Ft descendants of Chinese Cling, with the pollen
parent unknown. Greensboro behaved as a pure white in crosses,
but when selfed no progeny was obtained because of the failure of the
seeds to grow. St. John (yellow) X Early Wheeler (white) gave all
wlii to in the Ft, and St. John X Greensboro likewise gave all white
Fi seedlings. White flesh is dominant over yellow flesh. Crosses or
self-pollinations of homozygous white-flesh varieties have yielded all
white-flesh seedlings. Heterozygous whites have yielded three whites
to one yellow. Yellows have given all yellow.
This work makes the supposed parentage of Elberta somewhat open
to question. Elberta is a seedling of Chinese Cling, and the pollen
parent is thought to be some variety like Early Crawford. If Chinese
Cling wero pure white, as might be suspected from its early history,
then in a cross with a yellow variety the first generation seedlings
should all be white. However, Elberta as the Fi in this probable
cross is yellow, while Belle, a seedling of the same variety (Chinese
Cling) is white. The Chinese Cling parent of Elberta may not have
been a pure white. The work at Vineland, Ontario, Canada, reported
by Palmer (26), confirms that of Connors in showing that when a
homozygous white-flesh peach has been used as one of the parents,
all of the progeny will have white flesh. Yellow flesh behaved as a
pure recessive. It is perhaps more significant in considering the
parentage of Elberta that from 2,200 open-pollinated and selfed
seedlings of that variety, there has been none with fruit resembling
Early Crawford, the supposed pollen parent. Palmer has ventured
the opinion that Elberta is a natural selfed seedling of Chinese Cling,
a recessive yellow breeding true for that color.
Texture of flesh. — In the work of Connors, Elberta self -pollinated
seedlings showed a high percentage of firm fruit. Wherever Elberta
was used as a parent the result was a high percentage of firm-flesh
seedlings. Belle X Early Crawford gave a relatively high percentage
of firm-flesh seedlings. Soft flesh appears to be dominant over non-
melting flesh. The character for producing the tough flesh so desirable
692 YEARBOOK, 1937
for commercial canning is present in Belle, Carman, and Early Craw-
ford. Seedlings of these varieties, however, show red coloring of the
flesh about the stone, an undesirable character from a canning stand-
point.
Adhesion oj flesh to stone. — Connors noted that freestone appears to
be dominant over clingstone. In crosses between freestone varieties
the progeny has been about two freestones to one cling or semicling.
There are some varieties that are classed as semicling in which the
adhesion of flesh to stone is not very great. In some of these groups
such as Greensboro and Carman, the fruits in some seasons may be
nearly free. Frequently, if the fruits are allowed to remain on the
tree until well ripened, the flesh will almost completely separate from
the stone. The true clingstone type of peach is that represented by
varieties like White Heath and Red Bird, and the canning cling by
types like Phillips and Paloro. Freestones crossed with freestones
always gave a high percentage of freestones, the degree depending on
the variety. Belle and Elberta carry a factor for adhesion of flesh to
stone of about 33 percent. When freestones are crossed with cling-
stones a higher proportion of freestones than clingstones is obtained.
Inheritance of Other Characters
Foliar glands or nectaries. — The foliar nectaries of the peach are of
interest because it has been shown that glandless varieties are more
susceptible to some leaf diseases, particularly mildew, than varieties
with glands. Some commercial canning cling varieties now grown
in California, such as Paloro and Hauss, are glandless. These are
quite subject to mildew in some seasons and in some locations.
Rivers (27) reports that in crossing varieties having reniform glands
with glandless varieties, he obtained an intermediate type, which
was round or globose. Connors, in crossing some of our common
American varieties, such as Belle, Carman, Elberta, and Greensboro,
which are reniform, obtained seedlings all of which were reniform.
When these varieties were crossed with varieties with globose leaf
glands, the progeny was about 50-50 reniform and glandless. No
glandless varieties were selfed, but Bailey and French (2) report
all the progeny of a selfed glandless seedling were glandless. The F1
hybrids of a cross between reniform and glandless varieties all have
glands that are globose (fig. 10). The character is apparently
incompletely dominant.
Tree habit. — In crosses at the New Jersey station between Greens-
boro, spreading type, and Early Crawford, upright type, the seedlings
were all intermediate, none being the same as either parent. Seedlings
of Early Crawford, self-pollinated, were all upright. Seedlings of Lola
and Carman, which are spreading, were all spreading. The progeny
from selfed Elberta gave ratios of 1 upright : 2 intermediate : 1 spread-
ing. No dwarfs have appeared among the progeny of these varieties.
Size of blossoms. — With, blossoms the blending type of inheritance
is usually shown, with sometimes a slight apparent dominance of the
small-blossom type. In all cases studied by Connors, the large
blossoms and small blossoms were homozygous. Large crossed with
smallgaveallmedium,andthemediumsplitupinaratioof 1 :2: linthe
F2 generation. Large blossoms appear to be dominant in varieties
STONE FRUITS
693
bearing them, while varieties with small blossoms give small blossoms
in selfing. In crosses of large-petal types with small-petal types all
the seedlings had medium-size blossoms. This appears to be a case
of incomplete dominance.
Blooming date. — The majority of seedlings bloomed at practically
the same season as the parents, but a few individuals bloomed earlier
or later. Elberta and Belle, self -pollinated, gave some seedlings that
commenced blooming as much as a week after the parents. Slappcy
is a late bloomer, and all of its progeny were late.
Ripening date. — The hybrids usually ripened about midway be-
tween the parents, and it is rarely the case that a seedling ripens
Figure 10. — Types of foliar nectaries in tfie peach and the nectarine: A, Reniform or
kidney-shaped glands of Elberta peach; B, globose glands of Fitzgerald peach; C,
eglandular leaf of Lippiatls nectarine.
earlier than the early parent or later than the late parent. The
deduction is that the best chance to secure a new individual ripening
its fruit at a certain date would be by crossing two varieties the mean
of whose ripening dates would fall at the desired time. No marked
differences in ripening dates were observed. The majority of the
seedlings of the varieties used ripened about in season with the
parents, with some slightly earlier and some later than either parent.
Size of fruit. — Parents with small-size fruit are to be avoided.
Belle transmitted its character for good fruit size. Elberta seedlings
are practically all large-fruited.
Begirming in 1921, Connors used the J. H. Hale variety in a number
of crosses. During tbe period 1923-28, 42 crosses were made with
this variety. Blake and Connors (4), reporting on the results of these
crosses, state that the collection of characters in the J. H. Hale variety
was as a group recessive to the characters in varieties such as Chili,
Iron Mountain, Chinese Blood, and varieties with nonmelting type
694 YEARBOOK, 1937
of flesh. In the case of J. H. Hale X Chili the progeny of the cross
so closely resembled Chili in every way that it was impossible to dis-
tinguish many of them from the pollen parent. In summarizing the
evidence of inheritance of characteristics in the progeny of these J. H.
Hale crosses, Blake and Connors drew the following conclusions: (1)
Red flesh color about the pits is apparently dominant over absence of
red at the pit; (2) watery melting flesh texture is apparently dominant
over firm-melting flesh texture ; (3 ) nonmelting flesh is recessive to both
watery melting and firm-melting flesh texture; (4) blood red flesh was
dominant over the absence of red; (5) heavy pubescence is apparently
dominant over short or light pubescence; (6) oval-conic, oval-oblong,
and round-pointed forms in Chili, Iron Mountain, Chinese Blood, Japan
Dwarf Blood, and others were dominant over round; (7) full-dwarf and
semidwarf growth habit was recessive to standard tree size; (8) early
blooming, characteristic of Amygdalus kansuensis (Rehd.) Skeels, was
dominant over the late blooming ofJ.H.Hale;(9) vigorous sucker devel-
opment from the trunk and main branches characteristic of A. kansuen-
sis was dominant over the slight sucker development of J. H. Hale.
Characters Transmitted by Certain Varieties
Elberta transmits large fruit size, yellow color, and firmness of flesh,
freestone character, an extended period of ripening, a,nd a slight
tendency to sterility. The self -pollinated seedlings show better quality
than that of the variety itself.
Belle is a heterozj'gous white and is able to transmit white and
yellow flesh, a fair degree of firmness of flesh, a fair degree of freestone
condition, variability in period of ripening and blooming, and a
tendency to sterility.
Early Crawford transmits small fruit size, yellow flesh, a good degree
of firm or tough flesh, a fairly high degree of freestone character, tender
pubescent skin, and rather high acidity.
Greensboro transmits white flesh, good fruit size and color, hardiness
in bud, softness of flesh, and a clingstone character.
Slappey transmits small fruit size, dry, mealy, yellow flesh, lateness
of blooming, and nonadhesion of pulp.
Lola transmits small size, tendency to clingstone condition, and
tough flesh.
In tree habit the white-flesh varieties are more vigorous in tree
growth than yellow-flesh sorts.
Further genetic studies on the inheritance of characters in the
peach may be helpful in tracing the origin of the aforementioned
groups or races of peaches. This should be possible if prototypes of
our present-day varieties could be located, such as the large-petaled,
white-fleshed peaches of China, and the small and medium-petaled,
yellow-fleshed types found among varieties more common in western
Asia and the Mediterranean countries, and among the varieties now
commonly grown in this country.
Genetic Studies in England
Work at the John Innes Horticultural Institution in England with
the peach Royal George, having small flowers and small, eglandular,
serrate leaves, when selfed gave a progeny of seedlings with small
STONE FRUITS 695
flowers and eglandular, serrate-margined loaves. Royal George and
its progeny proved to be susceptible to mildew.
The Purple Leaf variety of peach (Blood Leaf) with large flowers,
purple leaves, reniform glands, shallow margin, finely serrate, when
solfed gave a small number of progeny, all having large flowers, purple
leaves, renif orm glands, and leaf margin similar to type.
Selfed nectarine (Lord Napier variety) with large flowers, large
leaves, reniform glands, and shallow crenate margin gave seedlings
with flowers and leaves similar to the parent. A few of the leaves
were almost serrate.
Two seedlings raised from a cross of Purple Leaf peach X Lord
Napier nectarine had purple leaves, but the pigment was less intense
than in the Purple Leaf parent or its selfed derivatives. This suggests
that the purple pigment in the peach behaves as a dominant, but the
reduction in the amount of pigment suggests a modifying factor.
Correlations
Hedrick (17) has pointed out a correlation between color of the
inside of the calyx cup and the color of flesh of the fruit. When the
calyx cup is greenish the fruit will be white, and when the calyx cup
is a deep orange the flesh of the fruit will be yellow. An intermediate
type is suggested by Connors in which the calyx cup is yellowish
buff, and following this the color of the flesh will be white, but the
tree carries a character for yellow flesh. This is true in the case of
Belle.
Another correlation, according to Connors, is that between leaves
and the color of the flesh. When the midrib and the veins of the leaves
of a variety have a yellowish cast the fruit is yellow, but if the midrib
or veins are pale green or whitish the fruit will be white.
Pollen Sterility
Most varieties of peaches are self -fruitful. Occasionally failure to
produce crops may be due to pollen sterility, which is exhibited in a
few commercial varieties, such as J. H. Hale, Halberta, Candoka,
Mikado, and Chinese Cling.
Connors in 1921-22 examined over 330 seedlings in the fruit-breeding
plots. J. H. Hale was the only variety that did not produce pollen,
and about 50 percent of open-pollinated seedlings of this variety were
pollen -sterile individuals. Progeny of some crosses with J. H Hale
have also shown about 50 percent of sterile individuals, while in other
crosses with this variety the progeny all produced pollen. It is sug-
gested that this type of sterility is recessive to the fully fertile flower
form. The failure of pollen-grain development' in J. H. Hale has been
found to be due to degeneration in the microspores some time previous
to blossoming. Apparently there are strains of this variety that pro-
duce pollen and are self-fruitful, but whether these have arisen as
somatic variations or have distinct ancestry is unknown.
Among seedling peach progenies examined the percentages showing
pollen sterility were: Belle selfed 21 percent, Belle X Elberta 17,
Elberta X Belle 14, Elberta selfed 13, Elberta X Early Crawford 7,
Elberta X Greensboro 5, and Belle X Greensboro 4 percent.
696
YEARBOOK, 1937
Chromosome Numbers in Peach Varieties
The basic chromosome number in the sex cells in the genus Prunus
is 8. The varieties of peach examined cytologically show the diploid
(2n) number of chromosomes to be 16. So far as known, no triploid
or tetraploid types have been discovered. If these have occurred in
the past they have apparently not been propagated or were discarded
in the search for new varieties. The fruit characteristics of the J. H.
Hale variety might suggest a tetraploid condition, but insofar as is
known they are not associated with tetraploidy.
The peach is rather a stable entity. No irregularities in chromo-
some behavior have been reported. Apparently reduction to the
haploid number in the formation of the sex cells prior to fertilization
and fruit development proceeds in a normal manner. Likewise in
somatic cell divisions no conspicuous irregularities have been reported
in chromosome behavior, and few varieties have been propagated as
true somatic mutations.
The problem of self-unfruitfulness, which is very important in the
case of other stone fruits and of apples, and which has stimulated con-
siderable cytological investigation with these fruits, is relatively un-
important in the peach.
Nearly all of our commercial varieties are self-fruitful, that is, they
set fruit with their own pollen. In a few instances varieties are self-
unfruitful because of pollen sterility.
Our present-day varieties are largely considered to be chance
seedlings, and many of them may have arisen as self-pollinated progeny
of various types. Some doubtless are the result of natural hybridiza-
tion. It is a fact, however, that many of these varieties are homozygous
for the genes controlling several of the characters studied.
Appendix (Peach)
Taiilk 3. — Locations of peach-breeding work and names of workers in the United Slates
and Canada
Stale or Province, institution, and
location
California:
Agricultural Experiment Station,
Da^is.
Agricultural Experiment Station,
Riverside.
' Chaffee Junior College, Ontario
IT. S. Department of Agriculture,
Palo Alto.
Illinois:
Agricultural Experiment Station,
tlrbana.
Iowa:
Agricultural -Experiment Station,
Ames.
Maryland:
U. S. Department of Agriculture,
Beltsville.
Agricultural Experiment Station,
College Park.
Massachusetts:
Agricultural Experiment Station,
Amherst.
Michigan:
Agricultural Experiment Station,
South Haven.
Year
work
was
begun
192.-
1907
1922
1907
1900
1931
1929
1918
1924
Early workers
E. B. Babcock, C. O.
Smith, IE. B. Frost.
C. S. CrandulL
S. A. Beach
E. C. Auditor, W. L.
Kerr.
Workers actively engaged at
present
W. A. Tufts, G. A. Philp.
J. W. Lesley.
George P. Weldon.
W. F. Wight, L. A. Thomp-
son.
J. C. Blair. M. W. Dorsey,
J. C. Whitmire.
T. J. Maney.
F. P. Cullinan, J. II. Wein-
berger.
A. L. Schrader, S. W. Went-
wortli.
J. S. Bailey.
Stanley Johnston, V. R.
Gardner.
STONE FRUITS
697
Tabms 3. — locations of peach-breeding work and names of workers in the United States
and Canada — Continued
State or Province, institution, and
location
Year
work
was
begun
Early workers
Workers actively engaged at
present
New York:
Agricultural Experiment
Geneva.
New Jersey:
Agricultural Experiment
New Brunswick.
Texas:
Station,
Station,
Station,
Station,
Station,
1805
1914
1035
1925
1914
S. A. Beach
C. 11. Connors
U. P. Hedrick, R. Welling-
ton, Olav Einset.
M. A. Blake.
S. H. Yarnell.
College Station.
Virginia:
Agricultural Experiment
Blacksburg.
Ontario, Canada:
Horticultural Experiment
Vineiand.
Fred W. HofMann.
E. V. Palmer, O. H. Dickson.
Peach and Nectarine Breeding Material at the United States Horticultural
Station at the National Agricultural Research Center, Beltsville, Md.h
Admiral Dewey
Admiral Dewey X St.
John
Alexander
Alton
Australian Saucer
Babcock
Banner
Barnard
Belle
Beers Smock
Berk Favorite
Best June
Bilyeu
Blood Flesh
Brackett
Briggs Red May
Canadian Queen
Candoka
Captain Ede
Carman
Chili
Chinese Cling
Champion
C. O. Smith
Cumberland
Curry
Delicious
Duke Hale
Early Crawford
Early Elberta
Early Imperial
Early Queen
Early Rose
PEACHES
Early Wheeler (Red Bird)
Eclipse
Elberta
Elberta X Phillips
Engle Mammoth
Eureka
Fairs Beauty
Father's Pride
Fay Elberta
Fitzgerald
Fei
Flaming Gold
Fox
Frances
Gage
George IV
Giant Snowball
Globe
Gold Drop
Gold Finch
Golden Jubilee
Greensboro
Halberta
Halehavon
Hale Early
Hauss X Foster
Heath Cling
Henrietta
Hiley
Hobson
Honey Dew
Hope Farm
Horton River
Hyslop
Illinois
Improved Crawford Late
Indian Blood Cling
Iron Mountain
Japanese Giant Cling
J. II. Hale
John Rivers
July Elberta
July Gold
June Elberta
Kalamazoo
Kathryn
Kette
Krummcl
Late Crawford
Leeton
Lemon Cling
Lemon Free
Levy
Libbee
Linworth
Lovell
Loving Cling
Luken Honey
Mammoth Heath Cling
Marigold
Mark
Markham Cling
Marquette
Martha Fern
Mathews
Maxine
Mayflower
Mikado
'The variety names in this and the following lists conform so far as practicable to the code of fruit variety
nomenclature. However, among them there is a considerable number of introductions from other countries,
selected strains of standard varieties tentatively designated, and other names applied temporarily, which
cannot be made to conform readily to the code. The publishing of such names in this connection is not to
be construed as the acceptance of them by this Department.
1.18004°— 37 45 ++
698
YEARBOOK, 1937
Miller Late
Minnie Stanford
Mountain Rose
Muir
Newcomb
Newhall
New Jersey 71
New Jersey 73
New Jersey 87
New Prolific
Niagara
N. J. 12722
Oldmixon Cling
Oldmixon Free
Opulent
P. G. W.
P. I. 36126
P. I. 43137
P. I. 68353
P. I. 101655
P. I. 101663
P. I. 101665
P. I. 101667
P. I. 101668
P. I. 101669
Boston
Gold Mine
Gower
P. I. 101675
P. I. 101676
P. I. 101677
P. I. 101680
P. I. 101681
P. I. 101682
P. I. 101687
P. I. 101688
P. I. 101689
P. I. 43289 XEarly
Crawford
Pallas
Peacharine
Peak Cling
Phillips
Pickett Favorite
Pioneer
Polly
Pratt Low
Ray
Red Indian
Rio Oso Gem
Roberta
Rochester
Radiance
NECTARINES
Hunter
Lipiatt Late Orange
Quetta
St. John
Salberta
Salwey
September Mammoth
Shalil (P. I. 63852)
Shippers Late Red
Sims
Slappey
South Haven
Stinson
Strawberry
Stump
Sun Glo
Texan
Triumph
Uneeda
Valiant
Vedette
Veteran
Viceroy
Vivid Globe
White Cling
White Hale
Wilma
Yellow Indian
Rivers Orange
Stanwick
Sure Crop
Peach and Nectarine Breeding Material at the California Agricultural
Experiment Station, Davis, Calif.
Admiral Dewey
Al
Alexander
Alpha Tuscan
Alton
Amsden
Angel
Annabel
Arp
Australian Saucer
Babcock
Banner
Barbara
Belle
Belle October
Best June
Bitterless Elberta
Bilyeu
Blood
Blood Cling
Blood Free
Blood Leaf Cling
Bokhara
Bolivian Cling
Brackett
Bresquilla
Briggs
Brock Beauty
Buckhorn
Burton's Hale Early seed-
ling
PEACHES
Cameo
Captain Ede
Carman
Carota
Carpenter
Champion
Chiloro
Cumberland
Cotogna di Siena
Crimson Cling
Cuban Nut
Currie Free
Dahling
Day Late Cling
Decker
Dorothy
Duchess of Cornwall
Earliest
Early Charlotte
Early Crawford
Early Elberta
Early Imperial
Early Japanese
Early Rose
Early Wheeler
Elberta
Elberta Cling
Estella
Eureka
Everbearing
Fav Elberta
Fei
Fitzgerald
Florida Gem
Florence
Foster
Frank
Frank seedling
Fredericka
Gaume
George IV
George Late
Gibbon October
Gilla Tardiva di Milano
Gillingham
Globe
Gold Dust
Goodman Choice
Golden Chinese
Golden Jubilee
Golden Sweet Cling
Golden Queen
Greensboro
Grosse Mignonne
Haight Late Free
Hale Cling
Hale Early
Harris
Harris Yellow Cling
Halford No. 1
Halford No. 2
Halford No. 3
STONE FRUITS
699
Heath Cling
Helen
Hobson
Home Freestone
Honey-
Honey Cling
Ideal
Ijam Tuscan
Illinois
Imperial
Japan Dwarf
Jewel
J. H. Hale
J. II. Keith Early May
Johnson
June Elberta
Katie
Klondike
Krummel
Lady Lindsey
Lady Palmcrston
La Grange
Late Champion
Late Crawford
Late Elberta
Late Tuscan
Leader
Lemon Cling
Leona
Levy
Libbee
Liberty
Lippiatt
Lovell
Luken Honey
Mammoth Heath
Massasoit
Mary
Mayflower
McDevitt Cling
McKevitt
Miller Late
Ming Tomb
Minnie Stanford
Mississippi
Monte Vista Cling
Morellone
Morris White
Mother
Motions Cling
Mothers Favorite
Mountain Rose
Mo wry Strawberry Cling
Muir
Muir Perfection
Munford
National
Advance
Ansenne
Boston
Breck
Cardinal
Davis
Newcastle Tuscan
Newhall
New Jersey-
Niagara
Nichols
Noble Red
October Beauty
October Indian
Octoberta
Oklahoma Beauty
Oldmixbn Cling
Oldmixon Free
Ontario
Opulent
Orange Cling
Oriole
Osprey
Pallas
Paloro
Paragon
Patison
Peak
Peento
Peregrine
Perfection
Phillips
P. I. 24807.
P. I. 32374
P. I. 35201
P. I. 36485
P. I. 41395
P. I. 43289
P. I. 43290
P. I. 43291
P. I. 55563
P. I. 55564
P. I. 55813
P. I. 55835
P. I. 61302
Picquet Late
Pinkham
Placer Cling
Pomona
Pratt Low
Prince of Wales
Pullar Cling
Radiant
Raisin Cling
Radiance
Red Bird (synonym
Early Wheeler)
Rio Oso Gem
Rochester
Runyon Orange Cling
Red Muir
Sabichi Winter
NECTARINES
Diamond Jubilee
Dixie
Downton
Dryden
Early Newington
Early Rivers
St. John
Salwey
Sea Eagle
Sellers
Selma
Shamrock
Shalil seedling
Sharpe
Sherman
Shippers Cling
Sims
Smith
Smith" Indian
Sneed
Stearns
Stinson
Strawberry
Summer Heath
Sunbeam
Sullivan
Stump
Suber
Susquehanna
Sutter Creek
Taylor
Tena
Texas
Thurber
Thurmond
Togo
Tosetti Late Free
Triana
Tribbles Cling
Tribbles Free
Tribbles Price
Triumph
Tuscan (synonym of Tus-
kena)
Tuskena
Up-to-Date
Vainqueur
Van Emmon
Vivid Globe
Victor
Waldo
Walton
Ward Late
Washington
West Late Free
of Wilbur
Wiley Cling
Wilma
Winter Freestone
Worth
Yellow Hiley
Yellow Swan
Fisher Yellow
Gaylord
Gold Mine
Gower
Griffith
Hardwiche
700
YEARBOOK, 1937
Humboldt P. I. 26503
J. C. Wees P. I. 29227
Kathryn P. I. 30648
Lippiatt P. I. 65973
Lord Napier P. I. 65974
Mexican P. I. 65975
Milton P. I. 65976
Muir P. I. 65977
Nettarino Gilla d'Padova P. I. 65978
New Boy P. I. 65979
New White P. I. 68178
Nigh Pineapple
Newton Quetta
Ozark Red Cling
Peach and Nectarine Breeding Material at the Georgia Agricultural Experi-
ment Station, Experiment, Ga.
Red Roman
Robinson
Smith
Spanish
Spencer
Stanwick
Stanwick Elrudge
Surecrop
Togatch Moneck
Traveller
Victoria
Violet
Wilkinson
Admiral Dewey
Alton
Annabel
Belle
Babcock
Banner
Best June
Best May
Brackett
Chilow
Chinese Cling
Cumberland
Delicious
Eureka
Early Rose
Eclipse
Elberta
Fertile Hale
Fitzgerald
Florida Gem
Gage Elberta
Georgia Hale
Golden Jubilee
Goldfinch
Halehaven
Hale seedling
Harpole Late Yellow
Honey
Indian Blood
Jewel
J. H. Hale
Kette
Krummel
Lemon Free
Luttichau
Manly
Marigold
Marquette
Mayflower
Mikado
Mountain Rose
New Jersey 46-B
New Prolific
Oriole
Paloro
Paloro No. 2
Picquet Late
Phillips No. 1
Pioneer
Rio Oso Gem
Riverdale
Rochester
September Mammoth
Shipper Big Red
Sims
Slappey
Sunbeam
Sun Glo
Tuskena (Tuscan)
Valiant
Vedette
Veteran
Walton
Weem Hale
White English
Willow Leaf
Wilma
Woodland Cling
NECTARINE
Red Roman
Peach and Nectarine Breeding Material at the New Jersey Agricultural
Experiment Station, New Brunswick, N. J.
A-l on Salwey Seedling (43124)
Admirable Jaune (P. I. 86168)
Admiral Dewey
Agostina (80128)
Aicken Cling (P. I. 88543)
Alberge Jaune (P. I. 101820)
Amarillo Tardio (P. I. 55835)
Amarillo Tardio (P. I. 55836)
Ambergem
Ames 2
Anna
Arp
Augbert
Aurora (P. I. 57688)
Australian Saucer
Banner
Barbara
Beauty Belle
Belle de Vitry (P. I. 102515)
Bennetts Perfection
Berks
Best June
Bilmeyer
Bolivian (P. I. 36126)
STONE FRUITS
701
Braekett
Briggs Early May (synonym of Briggs)
Burbank
Burbank Giant Freestone
Buttercup
Camelliaflore
Candoka
Chairs Choice
Charles Ingouph (P. I. 101825)
Chili
Chinese Blood
Chinese Cling
Clam Shell Elberta
Colora
Columbia
Connett
Crosby
Cumberland
D. B. Ansae (P. I. 88546)
Delicious
D'ltalia
Double Pink
Double Red Early
Double White
Duke of York
Dulce
Eagles Beak (P. I. 43289)
Early Crawford
Early Elberta
Early May
Early Rose
Early Wheeler
Eclipse
Elberta
Elberta Dwarf
Engle Monmouth
English Galande
Estella
Eureka
Exquisite
Fertile Hale
F. H. B. (43051)
Fitzgerald
Foster
Fox
Frances
Frank
Fredericka
Gallande (P. I. 66094)
Gcmmcr
General Lee
George IV
Gold Drop
Golden Elberta Cling
Golden Gem
Golden Heath
Golden Jubilee
Goldfinch
Goodman Choice on Salwey (68354)
Gordon
Goshawk
Greensboro
Grosse Mignonne (P. I. 76357)
Grosse Mignonne (P. I. 91763)
Grosse Mignonne (P. I. 102523)
Halberta
Hale Early
Halehaven
Hann Almond
Hardee
Harpole Late Yellow
Hauss
Heath Cling
Hiley
Hobson
Hope Farm
Ice Cream
Ideal
Illinois
Indiana
Indian Blood Cling
Indian Cling
Iron Mountain
Isquierdo (P. I. 57687)
Japan Dwarf Blood
Japan Golden Giant Cling
Jennie Worthen
J. H. Hale
J. M. Mack
July Elberta
July Gold
June Elberta
Kalamazoo
Kathryn
Katie
Kette
Kihi Kihi (P. I. 88547)
King Solomon
Krummel
Late Champion
Late Crawford
Late Elberta
Lecton
Lees Salwey (P. I. 88548)
Lemon Cling
Lemon Free
Leona
Lizzie
Lippiatt Late Red
Madeleine de Courson (P. I. 66095)
Mamie Ross
Marigold
Marquette
Marriages Late (P. I. 88550)
Massasoit
Maxine
Mayflower
Mexican Honey
Mitchelson (P. I. 88551)
Monkton No. 1 (P. I. 88552)
Monkton No. 2 (P. I. 88553)
Morris White
Motions Cling
Mountain Rose
Muir
Muir Perfection
National
Ohio Late Crawford
Oldmixon Free
Oriole
702
YEARBOOK, 1937
Pallas
Red Magdelaine (P. I. 57691)
Paloro
Rio Oso Gem
Pomona Majorada (P. I. 57689)
Rochester
Paragon
Rosebud
Prunus davidiana
Salberta
Peacharine
Salwey
Peento
Sant Anna (P. I. 102530)
Phillips
Sargents
P. I. 35201
Sellers Orange
P. I. 36485
Semi-Dwarf Elberta
P. I. 55564
September Monmouth
P. I. 55775
Shippers Cling
P. I. 55776
Shippers Late Red
P. I. 55885
Slappey
P. I. 55886
Sleepers Dwarf
P. I. 55887
Smock
P. I. 55888
South Haven
P. I. 56920
Stevens
P. I. 61302
Stinson
P. I. 63850
St. John
P. I. 63851
Strawberry Free
P. I. 63852
Stump
P. I. 63853
Sunbeam
P. I. 63855
P. I. 74011
Sun Glo
Sungold
P. I. 76202
P T 76361
Surprise
Tos China (P. I. 77877)
P I 88562
Tos China on Salwey (P. I. 77878)
P. I. 88561
P. I. 91762
P. I. 92159
Pioneer
Plummer (P. I. 88565)
Tos China on Salwev seedling (P.
77876)
Triumph
Tuskena (Tuscan)
Up-to-Date
Valiant
I
Polly (Ames 11)
Vanity
Veteran
Poppa de Venere (P. I. 102527)
Primrose
Vidette
Prunus kamuensis
Volaric (P. I. 107783)
Prunus mira
Pullar Cling
Waipawa on Salwev seedling (88556)
Waldo
Purple Leaf
Radiance
Watt Early (P. I. 57917)
White Hale
Ray
Wilma
Red A
Winner
Red B
Wm. Kane
Red C
Wrights Bountiful (P. I. 88567)
Red D
Wrights Late Red (P. I. 88558)
Red Bird (synonym of Early Wheeler)
Wrights Midseason (P. I. 88559)
Reeves
Yellow Greensboro
Reina Eleana (P. I. 57690)
Zelandia Peach (P. I. 88560)
NECTARINES
Blood Fleshed
Littles Yellow
Breck
Lord Napier
Cardinal
P. I. 65973
Diamond Jubilee
P. I. 65974
Flaming Gold
P. I. 65975
Garden State
P. I. 65976
G. O. Breeding
P. I. 65977
Goldmine
P. I. 65978
Gower
P. I. 65979
Humbolt
Pineapple
Sure Crop
Lippiatt Late Orange
Nectarine Peach (P. I.
Victoria
. 88554)
Yennman
STONE FRUITS 703
PLUMS
In the United States, as well as in Europe, the plum has long been
recognized as one of the most delicious of fruits, and among the stone
fruits it ranks next to the peach in commercial production. Many of
the varieties of plums now cultivated in the United States have been
introduced from many foreign countries, and when these are added to
the native varieties they give plums the largest number and greatest
diversity of kinds and species among the stone fruits. The fruits
exhibit a wide range of size, flavor, color, and texture. The plants
vary from small shrubs with drooping branches to trees of large size
with large, upright branches, and some have great beauty as orna-
mental plants (3, 19, 84).
The common European plum, known botanically as Prwnus do-
mestica L., appears to have originated somewhere in southeastern
Europe or western Asia, probably in the region around the Caucasus
and the Caspian Sea. Although it is called the European plum, De
Candolle, who summarized the history of these stone fruits, is very
doubtful whether P. domestica is indigenous to Europe. According
to the earliest writings in which this plum is mentioned, the species
dates back some 2,000 years. Another Old World plum species,
probably of European or Asiatic origin, is the damson plum, P.
insititia L. This species seems to antedate P. domestica, as is sug-
gested by the finding of damson plum pits in ancient ruins. The
ancient writings connect the early cultivation of these plums with the
region around Damascus.
It is not known just when European plums were introduced into
North America, but probably pits were brought over by the first
colonists. It is reported that plums were planted by the Pilgrims in
Massachusetts, and importations were made by the French into Can-
ada. These European plums have done remarkably well in the New
World, and today they constitute the most important group grown
commercially for canning and drying.
The native American plums were doubtless used for food by the
Indians long before the white man set foot on the shores of this conti-
nent. Reports of early explorers mention the finding of plums growing
in abundance. According to the descriptions of the early settlers,
these plums were inferior to the domesticas of the Old World in quality,
so that the colonists soon began importing varieties from Europe.
As a result, European plums soon became predominant in home
fruit gardens as well as commercial orchards in the northeastern United
States.
Another important species of more recent introduction into North
America is the Japanese plum, P. salicina Lindl., which was domesti-
cated in Japan and was introduced into the United States about 1870.
The Raw Material of the Plum Breeder
Cultivated varieties of at least 12 species of plums are to be found
in American orchards or growing in the wild, but most of the important
commercial varieties are confined to 4 of these species. A wealth of
types, varieties, and species is available for the fruit breeder.
The best known and most important of these groups are varieties
of Prunus domestica, the European plums and prunes. Unfortunately
704
YEARBOOK, 193 7
they are not well adapted to regions with hot, dry summers or dry, cold
winters. They are at home in the northeastern United States; in
sheltered sections along the Great Lakes and in the Intermountain
and Pacific Coast States they are at their best, as is evidenced by the
extensive production of fresh fruit and dried prunes in this region.
The European plums have been under domestication longest, and the
i 'Hft
X n
♦5
' ' .^»»
4 ^p
■jLi
* ' m
. /A1
^
Figure 11. — Types of fruit in the group of Prunus domestical A, Heine Claude, a high-
quality plum of the Green Cage group; B, Bradshaw, formerly an important variety
in the Lombard group of reddish plums used for canning and dessert, but being replaced
by better varieties produced as a result of hybridization and breeding; C, Diamond, a
blue plum of the Imperatrice group. The varieties of this group are of medium size,
dark blue in color, with a heavy bloom.
STONE FRUITS
705
fruits are notable for large size and attractive appearance. They vary-
in color from the green and golden yellow or the Reine Claude (Green
Gage) and Yellow Egg groups to the red and dark purple of the
Figure 12. — Some of the most important varieties of Primus domeslica used for making
prunes: A, Italian Prune, showing the shape of the fruits in the prune group; B, some
varieties that produce large prunes when dried.
Lombard and Italian Prune (fig. 11). Italian Prune, Agen, Sugar,
and Imperial Epineuse constitute an important group of European
plums with firm flesh and high sugar content suitable for use fresh or
as dried prunes (fig. 12). Other varieties, such as Tragedy, Reine
706
YEARBOOK, 1937
Claude, Bradshaw, and Golden Drop, are used principally for canning
and dessert plums.
The damsons (Prunus insititia) of the Old World are quite different
from the domesticas. The trees are more upright, compact, and
dwarfish, the leaves and flowers are smaller, and the fruits are small,
round, and quite tart, so that they are especially suitable for pre-
serves and jams. Varieties of this group are hardy, vigorous, and
productive, and the trees make good stocks for other species, being
adapted to a wide range of conditions and thriving even when they
are neglected. The Shropshire (fig. 13) and French arc important
Figure 13. — Shropshire, one of the most important varieties in the damson group of
Prunus insititia. This small blue plum, like others belonging to this group, is used
principally for preserves.
blue damsons in this country, while the yellow Mirabelles are popular
in France. The group as a whole has certain valuable qualities that
appear to have been overlooked in breeding investigations.
The Japanese plums (Prunus salicina) are relatively new to North
America, but in the short time since their introduction they have been
widely planted and now rank second to the domesticas in commercial
production. The trees are more spreading in habit than the domesti-
cas or damsons, and in leaf and fruit characters they are very different,
resembling the native American plums. The fruits are very attractive
and are characterized by a yellow ground color overlaid by various
shades of red. In some varieties the flesh color is a striking red,
whereas fruit of the domesticas and damsons is green or yellow. Some
recent hybrids of the salicina group (fig. 14) show distinct superiority
STONE FRUITS
707
Figure 14. — Plum hybrids. A, Prunus salicina hybrid, variety Apple. This red-
fleshed variety illustrates the round shape of the varieties of this species. B, America,
a hybrid between P. munsoniana and P. salicina. C, Hybrid resulting from a cross of the
purple-leaved plum P. cerasifera var. pissardii with P. salicina variety Abundance.
708 YEARBOOK, 1937
in flavor and in commercial possibilities over the early importations.
Varieties of this group appear to be widely adapted in this country
except in the very coldest climates. While the quality is not equal
to that of the best domesticas, the fresh fruit is delicious in its blend
of flavors. The varieties cross readily with one another and with
the native americanas. Among the first Japanese plums grown in
this country, Kelsey, Burbank, Abundance, and Satsuma are typical.
The trees are hardy and productive, and they tolerate a variety of
soils as well as climatic conditions. They blossom early, and the
flowers are sometimes killed by late spring frosts.
Among the plums native to North America are varieties that are
different in fruit and tree characters from the plums of Europe and
the Orient. Botanists have divided the native American plums into
a number of species and subspecies. Many of them have numerous
characteristics in common, so that they overlap somewhat in present
horticultural groups and classifications. Prunus americana Marsh.,
the most important of the native species, has a wide range of adapta-
tion in this country, extending from Maine to Florida, westward to
Utah, and northwestward into Manitoba. The tree is small, not as
vigorous as the European, and it has rough, shaggy, grayish bark.
The fruit is red, reddish yellow, or reddish orange, of pleasant flavor
and good quality, but it has a thick, tough skin, and the flesh clings
to the pit. De Soto and Weaver are among the typical cultivated
varieties of americanas.
Other American species of minor importance from a commercial
standpoint but of interest to the fruit breeder are the native varieties
of Prunus hortulana Bailey ; the Chickasaw plum, P. angusiifolia
Marsh.; and the wild-goose plums, P. munsoniana Wight and Hedr.,
of the southeastern and south-central United States, of which Wild
Goose and Robinson are important varieties (S, 32).
Other species of plums growing in North America are the Canada
plum, Prunus nigra Ait., which is adapted to the north-central United
States and Canada; the small beach plum, P. maritime/, Marsh., which
grows along the eastern seacoast; and the western or Pacific plum,
P. subcordaia Benth., which grows east of the Coast Range in southern
Oregon and northern California.
Finally, mention should be made of the myrobalan plum (Prunus
cerasifera Ehrh.), a native of Europe, and the Simon or apricot plum,
P. simonii Carr., a native of China. The myrobalan plum has been
used a great deal in this country as a rootstock. Varieties of P. cera-
sifera and P. simonii are noted for their ornamental foliage.
This great collection of varieties and species affords an excellent
opportunity not only for studying genetic relationships but for the
development of new varieties by breeding. The study of the in-
heritance of characters in plums has, however, not been very exten-
sive. This may be due in part to the fact that many varieties of
plums are self -unfruitful; that is, they do not set fruit with their own
pollen. This presents a problem to the fruit grower as well as to the
plum breeder. It is, of course, impossible to obtain an inbred progeny
to study the inheritance of characters if the blossoms cannot be selfed.
Fortunately for both the breeder and the fruit grower, fruits can be
obtained by cross-pollination, and not all varieties are self-unfruitful.
STONE FRUITS 709
Objectives in Plum Breeding
It is a well-recognized fact that plum culture in North America has
gradually been declining during the last 20 years. The reason for
this is the failure to keep pace with the demand for fruits of high
quality. Varieties that were satisfactory 25 to 50 years ago in most
cases do not appeal to persons who have a taste for fruits of high
quality. However, many varieties are still prized in the home garden
even though they are not profitable to the large producers.
An important objective of any plum-breeding program should be
the production of varieties of higher quality adapted to the various
fruit regions of the country. None of the domestica plums of high
quality can be grown satisfactorily south of Virginia or in the vast
regions of the southwestern and south-central United States. Native
American species grow in this part of the country, but their adapta-
bility must be combined with the higher quality of other varieties
and species. Work has been started in this direction, but it has met
with failure because domestica and americana varieties have different
chromosome numbers, and so far crosses between them have not
yielded viable seedlings.
Further study is also needed in the direction of artificially increasing
desirable mutations in plums. In a few instances desirable bud sports
have been discovered, and careful search should be made to locate
others.
In addition to high quality, consideration must be given to vigor,
hardiness, and productiveness. Much has been accomplished in
developing and selecting winter-hardy varieties for the Great Plains
region. Similar work is needed to develop varieties adapted to re-
gions with hot, dry summers.
Genetic and cytological studies are of first importance in initiating
a plum-breeding program. Among the self-compatible varieties
there is a wealth of valuable material that can be used as foundation
breeding stock. Even before methods are developed for increasing
fruitfulness in crosses between species, there is opportunity for re-
search on the material within many of the plum species growing in
this country. „ ,,
J Breeding Methods
The methods of breeding that have been described for the peach
apply equally well to the plum. The breeder is confronted with the
same problem of protecting the emasculated flowers in order to lessen
damage to the pistils. With varieties known to be completely self-
incompatible, emasculation is of course unnecessary, and time can
be saved by omitting this operation.
The problem of seed germination and the production of new seed-
lings likewise confronts the plum breeder. The seeds from many
crosses prove nonviable, and methods need to be worked out whereby
a greater percentage of seeds can be made to grow.
Work of Private Breeders
The first work on plum improvement in this country consisted of
attempts to obtain better strains of the native American plums by
domesticating seedlings and selecting those most promising for size,
710 YEARBOOK, 1937
flavor, and productiveness. The most extensive work in this direction
seems to have been started by H. A. Terry, of Crescent, Iowa.
From about 1860 until the time of his death in 1909 he had origi-
nated over 50 varieties from native species. While there is little
information available as to the breeding methods or parents used,
it is certain that he produced more new varieties than any private
breeder since his time. Some of the more important varieties intro-
duced by him are Gold, Hawkeye, Hammer, Downing, Crescent, and
Terry.
Work on the breeding of plums was begun by C. G. Patten, a
private breeder and a contemporary of Terry in the same State, at
Charles City, Iowa, in 1867. He was impressed by the great number
of native plums found growing in the wild, became interested in
domesticating some of these, and selected the best for the prairie and
upper Mississippi Valley regions. Hardiness or ability to withstand
cold winters was a factor to be considered in the selection of varieties
for that region. He worked with the American species. One of his
best selections was tested by the Iowa Agricultural Experiment
Station and was introduced as the Patten plum.
Beginning about 1870, J. W. Kerr, of Denton, Md., began the study
and testing of a large number of varieties of plums. He likewise was
interested in developing new varieties from native plums. Among the
varieties introduced by him are Choptank, Sophie, and Maryland.
In California, Luther Burbank began his plum-breeding work
about 1880, at Santa Rosa. He introduced and produced many
desirable types. Among the important varieties he developed from
seed imported from Japan are Burbank, Abundance, and Satsuma.
He was particularly interested in the Japanese types and did much to
popularize the varieties of this species in California, and to lay the
foundations for their later testing and use as important commercial
varieties in that State. He likewise made a number of crosses between
Prunus salicina and other species, producing Climax, Bartlett, and
Wickson from P. salicina X simonii, and America (fig. 14) and Golden
from P. munsoniana X salicina. Other varieties introduced that have
been grown commercially in California are Giant, Splendor, Standard,
Santa Rosa, Formosa, and Gaviota.
Hedrick and associates (19, p. 170-171) make the following com-
ment on Burbank's work:
One cannot briefly catalog the new forms of plants that have gone forth from
his private place in California; they must number well into the hundreds; his
biographer, in 1905, said that Mr. Burbank has worked with over two thousand
five hundred distinct species (Harwood, W. S., New Creations in Plant Life I.
1905). Among these have been practically all of the species of plums now under
cultivation, from which have been obtained, according to Mr. Burbank, hundreds
of thousands of plum-seedlings of which the breeder has selected a score or more
of very distinct sorts, all interesting and a few of them very valuable. The many
other fruits, flowers and forage plants which Mr. Burbank has sent out, each
involving the handling of countless seedlings, cannot be mentioned here. Nor can
his methods and results be discussed, except to say that in them he is a unique
figure in plant-breeding and that they have been such that he has exercised a
powerful influence toward the improvement of plants. The practical results of
Mr. Burbank's work have been as great or greater than those secured by any
other person in plant-breeding, yet they have been magnified out of all bounds in
the popular pressand his work has been caricatured by calling the man a wizard
and ascribing to him occult knowledge. Of the plants introduced by Mr. Burbank
STONE FRUITS 111
the proportion of really valuable commercial ones seems now to be small,
but what he has done cannot be measured by money values; he has awakened
universal interest in plant-breeding; has demonstrated that things unheard of
before his time can be done with plants; and, all in all, his contributions in new
forms of plants to horticulture and agriculture, in their intrinsic and educational
value, make him the master worker of the times in improving plants.6
Millard W. Sharp, of Vacaville, Calif., in more recent years has
produced and introduced several plum varieties. The method he
used was to top-work many varieties into a single tree, allow free
crossing, plant the seed, and make intensive selection of the resulting
seedlings. Of the varieties he introduced, Sharky and Becky Smith
have attained commercial importance.
Plum-breeding work has also been undertaken by Albert F. Etter
and August Etter at Ettersburg, Calif. In recent years they have
used as parents for hybrids Wild Goose, Marianna, Golden Drop,
Agen (French prune), Japanese varieties, and Sierra, a peculiar domes-
tica type that grows wild in Trinity County, Calif. ; two wild native
plums from Mongolia, and the native plums of Kansas. In all, this
includes about a dozen species. The outstanding ability to produce
new forms shown by the Sierra, the Kansas, and the Trinity plums is
of particular interest. The Sierra hybrids exhibit wide variations in
tree and fruit characters. These are under test at the present time,
but no varieties have been introduced.
Harlan Rockhill, of Conrad, Iowa, has been engaged in fruit breed-
ing since 1895. Among his recent selections are some promising plum
hybrids from crosses of Waneta X Apex, Waneta X Moorpark, No.
10 X P. I. 78519, Waneta dwarf seedling X Apex X P. I. 78519.
The last-mentioned cross is reported to be particularly hardy in wood
and bud, having withstood temperatures of —26° to —36° F. during
the winter of 1935-36. This variety and others are being tested
further.
Plum Breeding at State and Federal Stations
South Dakota
■ Work was undertaken at the South Dakota Agricultural Experiment
Station in 1895 by Hansen (15) in an attempt to select American vari-
eties of plum that would be satisfactory for the Great Plains region.
Up to 1937 fully 10,000 native plum seedlings of Prunus americana had
been grown in an endeavor to find native seedlings better in size and
quality than those already grown. Wastesa, Yuteca, Zekanta, Huya,
and Topa were selected and named. Yuteca is large ; Wastesa is out-
standing for size and quality. Hansen attempted to introduce
quality into the native plums by crossing these into a number of other
species such as peach, cherry, and apricot, as well as with other varie-
ties of plum. The following is a list of crosses made, together with
notes on the progeny:
Prunus besseyi Bailey (Bessey enerry or western sana cherry) X apricot
plum P. simonii Carr. Not hardy, fruits sparingly. One variety only named but
the trees have since been discarded.
P. besseyi X Japanese plum (P. salicina Lindl.). Progeny highly fertile, hardy,
widely cultivated. Among varieties named are Opata, Sapa, and Oka.
P. besseyi X native plum (P. americana Marsh.). Two varieties named,
Sansoto and Cheresoto, which are highly fertile.
6 Burbank's achievements and limitations have also been summed up critically by Jones (It).
712 YEARBOOK, 1937
P. besseyi X Apricot (P. armeniaca L.). Progeny very shy bearers.
P. besseyi X peach (P. persica) . Flowers of hybrid (Kamdesa) were sterile.
P. americana X simonii. Three varieties named, Toka, Hanska, and Kaga,
which are strong pollinators for other varieties. The fruit is fragrant, flesh firm,
and of excellent quality.
P. simonii X americana. This cross produced Tokata: the fruit is large and of
excellent flavor. The seedlings of this cross require cross-pollination.
P. salicina X americana. The progeny of this cross is highly fertile. Five
varieties have been introduced and widely cultivated — Waneta, Kahinta, Tawena,
Oziya, Tecumseh.
P. americana X salicina, the reciprocal of the former species cross, has yielded
many choice hybrids which are self-fertile and interfertile.
Canadaplum (P. nigra Ait.) X P. salicina. This combination has yielded the
varieties CTree and Pembina.
P. salicina X nigra has given the variety Ojibwa.
From Canada plum, Pruniis nigra, pure selections have been made and intro-
duced as Assiniboin and Winnipeg.
Since 1895 selections have been made from over a million seedlings of Prunus
besseyi. The thirteenth generation has now fruited.
New York
At the New York (State) Agricultural Experiment Station, Geneva,
plum breeding was started as early as 1893, when a few open-pollinated
seedlings^were grown. Under test the seedlings proved to be of no
commercial value. From 1908, when the first crosses were made at
the New York station, up to the present time, 78 varieties, 6 seedlings,
and 7 United States Department of Agriculture introductions have
been used in breeding work, and 546 crosses, 16 selfs, and 26 open
pollinations have been made. Only 519 seedlings bave been planted
in the orchard. The set of seed has not been high, and there were
serious losses between the time of harvesting the seed and planting.
Considerable difficulty has sometimes been experienced in getting the
seeds to grow. A few Japanese plums (Prunus salicina) have given
seedlings, but no seedlings have been obtained from the early-maturing
European or domestica group.
It has been the experience in the plum-breeding work at Geneva
that it is difficult to obtain large quantities of seed from hand-
pollinated trees. The flowering season is usually brief and there is
often a high mortality of blossoms. It has been suggested that the
use of tents and bees for pollination would be the economical method
for securing large numbers. The comparatively few seedlings that
have fruited indicate that it is not difficult to make rapid progress in
plum improvement. The large-fruited, attractive, poor-quality
Grand Duke has given promising new varieties when crossed with
high-quality Golden Drop and Agen. Imperial Epineuse and Pearl
have also imparted good quality to a high degree in crosses. The
varieties that have been used most extensively and the number of
times they have been used are: Abundance 23, Agen 23, Albion 8,
Archduke 8, Beauty 17, "Burbank 57, Clyman 11, Formosa 13, Golden
Drop 8, Grand Duke 23, Hall 12, Imperial Epineuse 30, Jefferson 8,
Miller Superb 10, Oullins 22, Reine Claude 19, Rivers Early 12,
Santa Rosa 16, Shiro 10, Stanley 16, Tragedy 8, and Yellow Egg 28.
A list of plum varieties introduced by the New York station is given
in table 4.
STONE FRUITS 713
Table 4. — Plum varieties introduced by the New York {State) Agricultural
Experiment Station
Variety introduced
Parentage
When
crossed
Year
intro-
duced
1929
1925
1925
1926
Purpose
Golden Drop X Grand Duke.
Imperial Epineuse X Mira-
belle.
Golden DropX Grand Duke,
Agen X Grand Duke
1908
1911
1908
1913
American Mirabello
Hall :...
Home and roadside market.
Do.
Commercial market.
The opinion is expressed by Richard Wellington that by intercrossing
hybrids such as Hall, Albion, and Stanley, and by crossing them on
high-quality plums such as Imperial Epineuse, varieties of better quality
should be obtained. A large number of varieties and species of plums
are grown on the grounds of the New York station as basic material
for the production of better varieties.
California
The California Agricultural Experiment Station at Davis has grown
a large number of varieties of plums on the station grounds. These
have been used in studies on pollination and variety behavior under
California conditions. Because of the demand for improved varieties
of plums, breeding work was started in 1934. Poor germination of
plum seeds has been an important factor in slowing down the produc-
tion of seedlings. All the species of plums grown in North America,
together with some miscellaneous species, are being utilized. A com-
plete list is given in the appendix. Genetic and cytological work on
interspecific crosses is under, way.
Iowa
At the Iowa Agricultural Experiment Station a large number of
plum crosses have been made, using Prunus americana, P. salicina,
P. domestica, and P. maritima; also P. armeniaca. Interspecific
hybrids between P. americana and P. salicina are grown, and 180
trees resulting from crosses between species and varieties are now being
grown in the nursery at Ames. These crosses were made during the
period 1931-33. Varieties used as pollen parents and the number of
times they were used are: Elliot 5, Hennepin 4, Japex 2, Monitor 2,
Sapa 5, Waneta 6, and Anthony, Zumbra, Red Wing, and Burbank
each 1. Crosses between the plum and the Russian and Moorpark
apricots have been made. Greenhouse trees are being utilized in the
breeding work with Prunus, and many hundreds of nonfruiting crosses
not listed above have been made on them. The interspecific hybrids
that prove to be fertile will be preserved for future crossing. The
trees are brought into the greenhouse about January 10 and are ready
for crossing about 3 or 4 weeks later.
Minnesota
Plum-breeding work at the Minnesota Agricultural Experiment
Station was begun in 1889 at University Farm by S. B. Green, horti-
culturist. In the same year breeding work was also started by E. H. S.
l,-!8!)04°— 37-
-40
714 YEARBOOK, 1937
Dartt at Owatonna Tree Station, a branch station of the University.
This work consisted of selection of open-pollinated seed from superior
native varieties. More extensive and systematic work began in 1907
with the establishment of the present University of Minnesota Fruit
Breeding Farm. Up to the present 20 varieties have been introduced —
Anoka, Elliot, Ember, Golden Rod, Hennepin, La Crescent, Mendota,
Monitor, Mound, Newport, Nicollet, Radisson, Red Wing, St. Anthony,
Superior, Tonka, Underwood, Waconia, Winona, and Zumbra. They
are of special interest for the upper Mississippi River Valley area
because of their winter hardiness, but are worthy of testing in other
sections also, and they should provide material for additional studies.
Detailed descriptions of these varieties, their parentage, and the dates
of introduction are given in the appendix, which also includes a list
of the varieties now being used in further breeding studies.
A considerable amount of breeding material is available involv-
ing various species of native and foreign plums and other closely
related species of stone fruits. Since winter hardiness is a primary
requisite, all breeding material is subjected to severe field tests to
determine its resistance to cold.
Federal Field Stations
A number of varieties and specific crosses of plum have been made in
cooperative investigations by the Bureau of Plant Industry, United
States Department of Agriculture, and Leland Stanford Junior
University at Palo Alto, Calif. The following varieties and species
have been used as seed parents: Agen, Anita X Sugar, Becky Smith,
Burbank, Clyman, Duarte, Fremonti, Giant, Golden Drop, Imperial
Epineuse, Improved French, Methley, Pond, Sergeant, Tragedy,
Wickson, and Primus bokhariensis Royle. In addition the following
varieties have been used as pollen parents: Sugar, Gaviota, Formosa,
Santa Rosa, Beauty, Satsuma, Standard, and Tunis. Two promising
hybrids, Methley X Wickson and Wickson X Santa Rosa, have been
selected. The latter variety is a delicious plum, representing a partic-
ularly fine blend of flavors and ripening just after Santa Rosa. The
tree is productive and in preliminary tests seems to be well adapted to
California conditions. A complete list of plum hybrids produced is
given in the appendix to this section.
At the Northern Great Plains Field Station, Mandan, N. Dak.,
more breeding work has been done with plums than with any other
fruit except apples. Thousands of seedlings have been grown from
the native wild plum and cultivated varieties. A great deal of varia-
tion is to be found within the Prunus americana species, and over 50
selections were made, some of which were propagated for a more
thorough test. A few of these are ready for more extensive testing in
the northern Great Plains area. Of late years a large number of
Japanese hybrid seedlings have been grown. Hybridizing work has
been in progress, using hardy P. americana and P. nigra varieties,
these being crossed with Japanese varieties, domestica varieties,
P. simonii, P. tomentosa Thunb., apricots, and cherries, and with
such hybrid plum varieties as Waneta, Underwood, and Sapa. Some
of the progenies are now bearing fruit, and a few selections have
been made.
STONE FRUITS 715
Plum Breeding in Canada
Plum breeding at the Horticultural Experiment Station, Vineland,
Canada, was started in 1913. From 1913 to 1935, 4,240 seedlings were
grown. Seeds were planted from 57 open pollinations and 35 crosses.
Out of this number 16 had horticultural value. During the period
1931 to 1933, 860 seedlings were grown from crosses in which Imperial
Epineuse was used as the female parent, and Grand Duke, Coe
Fellenberg, and President have been used as pollen parents. The
object of the cross was to produce a high-quality blue plum for the
export trade.
Genetic and Cxtological Studies of the Plum 7
Experiments with plums were begun at the John Innes Horticultural
Institution in England by W. J. Backhouse and Crane (8) in 1911, to
investigate the genetic composition of plum trees by raising selfed
offspring. The characters studied were (1) hairiness of shoots,
leaf petioles, and fruits; (2) smoothness of bark and size and
shape of leaves; (3) habit of growth of tree; and (4) bark and fruit
color.
All the varieties of plums studied with hairy wood surface proved
to be heterozygous for that character. Serrate leaf character proved
to be homozygous in the Pershore variety, and crenate leaf margin
homozygous in the Czar family. The irregular margin appeared to be
heterozygous in varieties possessing this character.
Flesh color varied. Varieties in which yellow was the predominat-
ing flesh color have, when selfed, given seedlings with a green, and a
wholly yellow flesh.
As to fruit size and shape, many of the differences were recognized
as doubtless quantitative. The oblate fruit of Early Transparent, for
example, and the pyriform fruit of the Pershore variety proved to be
homozygous for these forms. With some selfed families, length and
shape varied in the progeny.
Wellington {82) has carried on extensive investigations at the New
York (State) Agricultural Experiment Station in breeding and genetic
studies with a number of plum varieties and species. He found the
oval fruit shape of Prunus domestica dominant to oblate. Thick bloom
on the surface of the fruit is dominant to thin bloom. Yellowy color is
recessive to red, purple, and black. The freestone character is reces-
sive to clingstone. Many varieties are heterozygous for. the freestone
character, freestones being obtained from the cling and semicling
parents.
Some varieties of our domestica plums set fruit with their own
pollen; others are partially self -incompatible, while a third group fail
entirely with their own pollen. Instititia varieties grown in this
country are self-fruitful. Nearly all of the varieties of the Japanese
group are self-sterile.
Tufts has found the following important varieties of domestica
plums to be self-unfruitful in California: Clyman, Tragedy, Imperial
Epineuse, President, Standard, Sergeant, Washington, Jefferson,
Quackenboss, Diamond, and Silver. Self-fruitful varieties were
' This section is written primarily for students and others professionally interested in genetics or breeding.
716 YEARBOOK, 1937
Agen, Giant, Pond (partially), Grand Duke (partially), California
Blue, Yellow Egg, and Sugar .
The following Japanese and hybrid plums were self-unfruitful in
California: Abundance, Burbank, Duarte, El Dorado, Formosa,
Gaviota, Kelsey, Prize, Satsuma, Sultan, Upright, and Wickson.
Methley, Climax, Beauty, and Santa Rosa are partially self-fertile.
Formosa and Gaviota were also found to be interunfruitful. The
Tragedy plum will fertilize several Japanese varieties but is not fer-
tilized by them.
Crane and Lawrence (10) observed that certain of the domestica
plums were completely self-and cross-incompatible, while others,
such as President and Late Orange, were reciprocally incompatible
but set fruit wben pollinated with Green Gage (probably Reine
Claude). Early Rivers, when pollinated by Blue Rock, set a full
crop, while in the reciprocal cross only a few fruits set. Varieties
such as Golden Drop, Coe Violet, and Jefferson, were found to be
completely self- and cross-incompatible (9) .
Incompatibility Due to Genetic Make-up
Experiments by a number of investigators, East (IS), Lehmann
(24), and others, have shown that sterility is determined by genes
just as are morphological characters. East designated these genes S,
and they form a multiple allelomorphic series, S1} S2, S3) etc. As in
the case of other allelomorphs, any two may be carried by a given
plant. While this concept is based on the results of studies with
Nicotiana, it fits into the observations made on stone fruits and
explains incompatibility in plums and cherries. The essential features
of the genetic behavior of incompatibility is that pollen cannot func-
tion in the style of a plant carrying the same incompatibility factors
as the pollen. Self-pollinations or cross-pollinations among indi-
viduals carrying the same sterility genes fail because either the
pollen tubes grow so slowly that in normal cases they are unable to
reach the ovules in time to effect fertilization, or the growth of the
pollen tube is inhibited in the stylar tissue. Consequently, groups of
individuals occur within which all cross- and self-pollination fails to
effect fertilization. Thus, individuals of the constitution Si, S2,
cannot be fertilized by Si or S2 pollen. If, however, such individuals
are crossed by S3 S4, both the S3 and S4 pollen can penetrate the
style of the mother and effect fertilization. It will be seen that the
offspring from such a cross, allowing all combinations possible, will
constitute four intrasterile, interfertile groups of the composition
Si S3, Si Si, S2 S3, S2 S^
With certain of our plum varieties, of either the Japanese or the
domestica species, self-unfruitfulness occurs when those varieties
carry a gene for incompatibility. Likewise, varieties would be cross-
unfruitful if both parents carried the same genes for incompatibility.
Chromosome Numbers in the Plums
In the genus Prunus the basic chromosome number is 8. All the
varieties examined among the myrobalan plums (P. cerasifera),
American plums (P. americana), and Japanese plums (P. salicina)
STONE FRUITS
717
show the diploid number (2w) to be 16. Other species, notably the
sloe (P. spinosa L.), have the tetraploid number or 32 chromosomes,
and a still greater number (48) is found in the important groups of
European plums (P. domestica) and the damsons (P. insititia).
Hybrids of Prunus domestica (48) X P. cerasijera (16), and P.
insititia (48) X P. spinosa^ (32) have the intermediate chromosome
numbers, 32 and 40, respectively.
According to Crane and Lawrence {10), the hybrids that they have
obtained between Prunus domestica and P. insititia, both hexaploid,
have always been completely interfertile; but from crosses between
diploid and polyploid, and different polyploid forms, such as P.
domestica X P. cerasifera and P. insititia X P. spinosa, fruits with
viable seeds are rarely produced. Crosses between damsons and
other varieties of P. insititia and P. domestica when attempted have
always set fruit and developed good seeds freely. Wellington has
also made many interspecific crosses. Crosses have been made
successfully between P. domestica and P. insititia. With a large
number of other interspecific crosses, however, involving P. domestica
X P. armeniaca and its reciprocal ; P. domestica X P. tomentosa, and
P. domestica X P. americana, few fruits were obtained or the seeds
failed to grow. Insofar as is known, triploid varieties of Prunus are
found only as ornamentals, their degree of sterility being too high to
enable them to be grown for their fruits.
Appendix (Plum)
Table 5. — Locations of plum-breeding work and names of workers in United States
and other countries
State or country, institution, and
location
California:
Agricultural Experiment Station,
Davis.
U. S. Department of Agriculture,
Davis.
IT. S. Department of Agriculture, Palo
Alto.
Iowa:
Agricultural Experiment Station,
Ames.
Minnesota:
Agricultural Experiment Station, Uni-
versity Farm, St. Paul.
New York:
Agricultural Experiment Station,
Geneva.
North Dakota:
TJ. S. Department of Agriculture,
Northern Great Plains Field Station,
Mandan.
South Dakota:
Agricultural Experiment Station,
Brookings.
Canada:
Horticultural Experiment Station,
Vineland, Ontario.
England:
John Innes Horticultural Institution,
Merton.
Australia:
Department of Agriculture, Sydney,
New South Wales.
Early workers
E. J. Wickson, W. L. Howard,
A. H. Hendrickson.
S. A. Beach .
Charles Haralson, M. J. Dorsey,
W. S. Valleau, J. H. Beau-
mont.
U. P. Hedrick, W. H. Alder-
man, M. J. Dorsey.
Max Pfaender_. .__
N. E. Hansen,.
Workers actively engaged
at present
W. P. Tufts, E. C. Hughes.
J. E. King.
W. F. Wight.
T. J. Maney.
W. H. Alderman, A. N.
Wilcox.
R. Wellington, Olaf Ein-
set.
William P. Bated.
N. E. nansen.
F. E. Palmer, G. H. Dick-
son.
W. J. C. Lawrence.
II. Wenholz.
718 YEARBOOK, 1937
Table 6. — Varieties used in plum breeding at the University of Minnesota
Parentage
Period
during
which
crosses
were
made
Total
seedlings
grown
Seed-
lings of
horti-
cultural
value
Appar-
ent value
ol
parents
used
1915
1925-27
1926
1920- 26
1925-26
1913
1912
1920-25
1920-26
1927
1923-27
1923-26
1913-26
1922-27
1920
1920
1920
1921
1920
1921
1921-26
1924-26
1924-26
1921-26
1921
1912-21
1912-26
1923-27
1912
1912
1912
1912
1912
1922-27
1920
1920-21
1924
1924
1912
1912
1912
1912
1920-21
1920-23
1920
1912
1920
1920-21
1920
1912
1924
1912
1912
1912
1913
1912
1912
1912
1924-26
1924
1924
1925-26
1912-15
1920-25
1920
1920
1912
1912
1921
1921
1912
1915
Number
208
229
181
26
6
43
27
233
15
10
14
39
279
70
19
2
72
10
30
48
9
89
13
10
1
20
77
2?
31
60
107
37
21
25
179
30
5
15
39
23
20
81
156
54
3
60
21
25
Number
16
Fair.
3
1
33
Reciprocal cross _ .. .
Fair.
Good.
Burbank X Older.
Bnrhank Open
3
2S
1
1
1
2
Burbank X Primus amerieana..
Good.
Burbank X Red Wing ...
Fair.
Fair.
2
Fair.
Burbank X S. Dak. No. 27
i
Burbank X Surprise. ._
Burbank X Wakapa . _
2
6
Burbank X Wolf
Good.
(Burbank X Wolf) open... ... _ ..... ... _ ...
2
5
1
Compass X Climax. . _ . _ _
Do.
Do.
Early Red X P- amerieana _
Elliot X Mendota
Poor.
Emerald X (Wyant X Gold).
Omaha X Burbank.. _ _
4
2
Good.
Omaha X Winnipeg _
(Pin cherry X sweet cherry) X sand cherry or sand cherry
hybrid. _
11
Good.
Red Wing X Kaga
2
Fair.
5
1
Good.
(Sand cherry X Climax) X Tonka. _ .
3
4
27
24
26
29
21
31
. 1
38
1
50
23
1
91
72
209
33
3
45
28
26
3
22
93
Good.
1
4
7
Good.
Shiro X S. Dak. No. 33
Do.
7
1
Do.
S. Dak. No. 27 X Monarch
S. Dak. No. 27 X October Purple
S. Dak. No. 27 X Santa Rosa
7
1
Good.
Stella.open . . _
Tonka X Assiniboin
Tonka X Red Wing.._. _._
Wakapa X Wyant
Winnipeg, open
4
Fair.
STONE FRUITS 719
Table 6. — Varieties used in plum breeding at the University of Minnesota — Continued
Parentage
Zekanta X P. americana
Minn. No. 2 (Burbank X Wolf) X Burbank
Reciprocal cross ___
Minn. No. 6 (Burbank X Wolf) X Terry
Minn. No. 10 (Abundance X Wolf), open __.
Minn. No. 35 (Abundance X Wolf) X Burbank
Reciprocal cross. .
Minn. No. 55 (Abundance X Wolf) X No.57 (Shiro X Winnipeg).
Reciprocal cross _
Minn. No. 55 (Abundance X Wolf) X No. 63 (Shiro X Winni-
peg).
Minn. No. 55 (Abundance X Wolf) X No. 90 (Burbank X
Wolf) 21.
Minn. No. 55 (Abundance X Wolf) X No. 104 (Burbank X ?) ...
Minn. No. 59 (Shiro X Winnipeg) X No. 57 (Shiro X Winnipeg) .
Reciprocal cross
Minn. No. 62 (Shiro X Burbank) X No. 57 (Shiro X Winnipeg).
Minn. No. 66 (Shiro X Wolf) X No. 65 (Shiro X Wolf)
Reciprocal cross
Minn. No. 76 (Burbank X P. americana) X No. 62 (Shiro X
Burbank).
Minn. No. 84 (S. Dak. No. 33 X Shiro) X No. 77 (Shiro X na-
tive) .
Minn.No. 90 (Tonka open) X No. 55 (Abundance X Wolf)
Minn. No. 92 (Omaha X Wyant) X No. 74 (Santa Rosa X Bur-
sota X Winnipeg).
Reciprocal cross _
Minn. No. 92 (Omaha X Wyant) X No. 106 (Omaha X Santa
Reciprocal cross
Minn. No. 98 (?) X Winona, reciprocal cross
Minn. No. 98 (?) X No. 96 (Zekanta X apricot).
Minn. No. 106 (Omaha X Wyant) X No. 55 (Abundance X
Wolf). '
Period
during
which
crosses
were
made
1912
1921
1921
1023
1912
1920
1920
1924-26
1921-26
1924-26
1024
1924
1924-27
1925-26
1924-25
1924-25
1925
1925-26
1924-26
1924
1924
1925
1923
1925
1926
Total
seedlings
grown
Number
20
18
18
21
30
10
97
64
Go
40
87
25
64
4
63
25
1
23
111
95
2
64
6
24
20
36
Seed-
lings of
horti-
cultural
value
Number
2
Appar-
ent value
fit
parents
used
Fair.
Poor.
Do.
Poor.
Do.
Table 7. — Plum introductions of the Minnesota Agricultural Experiment Station
Variety
Anoka (Minn. No. 118).
Elliot (Minn. No. 8)...
Ember (Minn. No. 83).
Golden Rod (Minn.
No. 120).
Hennepin (Minn. No.
132).
La Crescent (Minn.
No. 109).
Mendota (Minn. No.
5).
Monitor (Minn. No.
70).
Mound (Minn. No.
50).
Newport (Minn. No.
116).
Nicollet
Parentage
Burbank XDe Soto- .
Probably apple plum
X Prumis americana.
Shiro X S. Dak. No.
33.
Shiro X Howard Yel-
low.
Satsuma X P. ameri-
cana.
Shiro X Howard Yel-
low.
Burbank X Wolf.
Probably Burbank X
P. americana.
Burbank X Wolf.
Omaha X Pissardii....
(P. avium X pensyl-
vanica).1
When
crossed
or seed
col-
lected
When
intro-
duced
1922
1920
1913
1907
1913
1936
1913
1923
1911
1923
1913
1923
1908
1924
1912
1920
1908
1922
1913
1923
1912
1925
Descriptive notes (special
value and superior characters)
Hardy; productive
Very hardy; productive;
good quality; late season.
High quality; late season;
long-keeping quality; ex-
ceptional adherence to tree.
Vigorous tree; larger firm
yellow fruit. (Variety a
shy bearer.)
Hardy; productive; red flesh.
Very high quality; large,
vigorous tree.
Very large fruit; good quality.
Large, high-quality fruit;
hardy; regularly produc-
tive.
Large size of fruit; produc-
tive.
An ornamental with purple
foliage.
Dwarf, bushlike; fruit simi-
lar.
Esti-
mated
acreage
now
planted
Small.
175 acres.
Small
50 acres.
Small.
100 acres.
Small.
300 acres.
(0.
25 acres.
50 acres.
i All in scattered landscape plantings.
1 Open pollen parent is Prunus besseyi or a hybrid ol this species.
720 YEARBOOK, 1937
Table 7. — Plum introductions of the Minnesota Agricultural Experiment Station — Con.
Variety
Parentage
When
crossed
or seed
col-
lected
When
intro-
duced
Descriptive notes (special
value and superior characters)
Esti-
mated
acreage
now
planted
Eadisson (Minn. No.
157).
Red Wing (Minn. No.
12).
St. Anthony (Minn.
No. 145).
Superior (Minn. No.
194).
Tonka (Minn. No. 21).
Underwood (M inn.
No. 91).
Waconia (Minn. No.
10).
Winona (Minn. No.
80).
P. salkina X amer-
icana.
Burbank X Wolf
P. besseyi (or hybrid)
X Satsuma.
Burbank X Kaga
Burbank X Wolf
Shiro X Wyant
Burbank X Wolf.
P. salkina X ameri-
cana.
(P. avium X pen-
sytvanica)J
1008
1908
1912
1920
1008
1911
1908
1909
1912
1925
1920
1923
1932
1920
1920
1923
1922
1920
Early-maturing high-quali-
ty fruit; adapted to north-
ern locations.
Large high-quality fruit;
exceptional freestone.
Very hardy and productive;
red flesh.
Very productive and early
bearing; fruit very large,
firm, excellent quality.
Very productive; firm flesh;
high quality.
Very vigorous; hardy; pro-
ductive; early ripening;
excellent quality.
Hardy; productive; quality
only fair.
Ilardy; productive; high
quality; late season.
Dwarf, bushlike; very pro-
ductive; excellent culinary
quality.
Small.
250 acres.
50 acres.
100 acres.
300 acres.
500 acres.
Small.
Do.
2 Open pollen parent is Prunus besseyi or a hybrid of this species.
Plum Hybrids Produced and Under Test in Breeding Investigations of
United States Department of Agriculture and Leland Stanford
Junior University at Palo Alto, Calif.
Year Parents
1921 Agen X Anita.
1931 (Agen X Anita 18-31) X Imperial Epineuse.
1929 Agen X (Coe X Sugar).
1922 Agen X Standard.
1920 Agen X Sugar.
1931 (Agen X Sugar 18-12) X Imperial Epineuse.
1920 Anita X Sugar.
1931-32 (Anita X Sugar) X Agen.
1934 Becky Smith X Tunis.
1920 Prunus bokhariensis X Methley.
1921 P. bokhariensis X Sugar.
1920 P. bokhariensis X Wickson.
1934 Burbank X Formosa.
1932 Burbank X (P. fremonti X cerasifera pissardii 1 1-3 8) .
1933 Burbank 2010 X Gaviota.
1932 Burbank X Satsuma.
1932 Clyman 12010 X (Anita X Sugar 18-45).
1934 Duarte X Santa Roas.
1933 (P. fremonti X cerasifera pissardii 11-31) X P. bokhariensis X Methley
6-6).
1924-26 Giant X Imperial Epineuse.
1919 Golden Drop (Coe) X Sugar.
1931 (Golden Drop (Coe) X Sugar) X Imperial Epineuse.
1926 Imperial Epineuse X Improved French.
1924-26 Imperial Epineuse X Tragedy or Agen.
1926 Improved French X Tragedy.
1920 Methlev X Wickson.
1935 (Methlev X Wickson 11-56) X Beautv.
1932-33 (Methlev X Wickson 11-54) X Satsuma.
» The hyphenated numbers following certain varietal names refer to row and tree locations.
STONE FRUITS
721
1933 (Mcthley X Wickson 11-57) X (Wickson X Santa Rosa 15-23).
1921 Pond X Agcn.
1926 Sergeant X Improved French.
1926 Tragedy X Clyman.
1921 Wickson X P. bokhariensis.
1933 Wickson 7-24 X (P. bokhariensis X Methley 6-6).
1921 Wickson X Santa Rosa.
1935 Wickson X (Wickson X P. bokhariensisl5-2l) .
Plum Material at the California Agricultural Experiment Station,
Davis, Calif.9
Prunus domestical
Admiral
Agen (French)
Altharm
Anita
Archduke
Arctic
Austrian Prune
Autumn Compote
Bavay
Bird Prune
Bittern
Black French
Black Prince
Blue Rock
Boddaert
Bradshaw
Bridge
Bulgarian
Burton Prune
California Blue
California Red
Callas
Champion (Burton)
Champion (Villa)
Clairac Mammoth
Clyman
Coates 1401
Coates 1403
Coates 1414
Coates 1418
Columbia
Communis
Crimson Drop
Curlew
Czar
De Caisne
De Montfort
Denbigh
Diamond
Diana
Dosch
Double X French
Duane
Duchess
Dulce
Dunlap
Prunus domestica — Con.
Earliana
Early Favorite
Early Golden Drop
Early Royal
Early Tragedy
Emilie
Empire
Femonzi
Field
Florence
Frauleiu
German Prune
Giant
Gill
Golden Drop
Golden Prune
Golden Transparent
Goliath
Grand Duke
Green Gage
Gueii
Hall
Hand
Hector
Heron
Honori
Hulings
Hungarian
Ickworth
Imperial
Imperial Gage
Italian Prune
Jefferson
Junction City Prune
June Fourth
Kaiser
Kimball
Kirkc
Large English
Late Orange
Late Orleans
Late Tragedy
Leighton Italian
Liberty Prune
Lincoln
Prunus domestica— Con.
Lombard
Long Green
Long Stem
Los Angeles
Lucombc
Mallard
Margaret
McLaughlin
Middleburg
Miller Superb
Missouri Green Gage
Monarch
Monk
Mount Royal
Mover
Napa
Newark
New Oregon Prune
Oullins
Pacific
Palatine
Papagone Prune (P. I.
40498)
Peach
Pearl
Peters
Pond
President
Primate
Prinlow
Purple Gage
Quackenboss
Rayburn
Reuter Early Italian
St. George
St. Jean
St. Martin
Sannois
Sergeant
Sharpe Imperial
Shipper
Silver Prune
Smith Orleans
Smith Late
Splendor
» This list of variety names is approximately as submitted by the California station. The names are those
under which the material is recorded, and not all of them are necessarily intended as authentic variety
names. The list apparently contains a considerable number of names representing local strains and other
names that do not conform to the generally accepted code of nomenclature. It is impracticable to attempt
to bring the nomenclature in all cases into harmony with the code, therefore only a few changes representing
obvious differences have been made.
722
YEARBOOK, 1937
Prunus domestica — Con.
Standard
Stanley
Stark Green Gage
Steward Prune
Stint
i Stuart
Sugar
Super Prune
Swan
Sweetest
Tardeva de Moleta
Tatge
Tennant
Tragedy
True Blue
Tulare
Turkish Prune(synonym
of Italian Prune)
$2000 Prune
Uncle Ben
Ungarish
Victoria
Voronesh
Wales
Washington
Wilhelmina
Williamson Tragedy
Yakima
Yellow Egg
Yellow Gage
Yellow Imperial
York State Prune
Zucheriva del Vesuvia
Prunus salicina:
Abundance
Alpha
Amador
Apex
Beauty
Becky Smith
Best's Hybrid
Blood Plum
Blue Gown
Botan
Burbank
Burton
Chabot
Clarice
Collie
Del Norto
Earliest of All
Engre
Extra Early Satsuma
Florida
i Georgeson
' Hale
IXL
Kelsey
McRea
Miss Edith
Prunus salicina — Con.
Occident
October
Ogon
Pasha
Purple Flesh
Raisin
Red June
Sachem
Santa Rosa
San Francisco
Satsuma
Schattenburg
Sherkey
Strang
Tribble Early Beauty
Ulatis
Valleda
Willard
Wilson
Wright Earlv (P. I.
43180)
Wright Purple (P. 1.
43181)
Prunus americana:
Admiral Schley
Advance
Desoto
Golden Queen
Hawkeye
Klondike
Muncy
New Ulm
Quaker
Skuyu
Stoddard
Weaver
Wolf
Wood
Wyant
Prunus americana var.
mollis Torr. and Gray:
Gloria
Terry
Prunus nigra:
Aitken
Cheney
Eureka
Plumcots (so-called):
Francis I
Poe Royal Cot Plum
Rutland
Sharpe
Smith
Sparks
Stanford
Triumph
Velvet
Prunus insilitia:
Big Mackey
California Wild
Prunus insititia — Con.
Crittenden
Damson Free
Damson Majestic
French damson
Frogmore
King damson
Merry weathers
St. Julien
Shropshire
White damson
Prunus munsonianat
Clifford
Downing
Early June
Freestone Goose
Jewell
Late Goose
Monthalia
Newman
Oxheart
Poole Pride
Pottawattomie
Wildgoose Improved
Woo ten
Native plum:
Zekanta
Prunus horiulana:
Forest Garden
Golden Beauty
Minco
Robinson
Surprise
Way land
Prunus horiulana var. mi-
neri Bailey:
Miner
Prunus bokhariensis:
P. I. 40224
Species unknown:
May Queen
Progressive
Superior
Prunus cerasifera:
De Caradenc
Early Cherry
Extra Early Cherry
Myrobalan
Paragon
Prunus anguslifolia var.
varians Wight and
Hcdr.:
Eagle
McCartney
Prunus orthosepala
Koehnc:
Prunus orthosepala
Prunus subcordata Benth.:
Sierra
Prunus simonii:
Simon
STONE FRUITS
723
Supposed parentage •
S X Si
Mu X S
S X ?
CX S
S X Si
S X ?
S X ?
S X A X ?
I X S
S X Mu?
S X A
S X Si X ?
Si X ?
B X A
A X S
S X Si
S X ?
IX D
A X Ma
S X A X Si
S X Ch
(Mu X S) X S
S X Si X ?
S X A
?
S X A
S? X D
B X Na
B X S
S X Mu
B X S
S X ?
S X A
S X ?
S X ?
S X A X ?
(Mu X S) X ?
A X Si X S
Ma X Si X A X
S X Mu
S X Na
H Mi X A
A X Si
S X ?
S X hybrid
S X hybrid
S X A
S X Si X ?
A X S
S X Ch
Mu X S
S X ?
A X Si
A X N
HYBRIDS OB SUPPOSED HYBRIDS
Variety
Alhambra
America
Apple
Banana
Bartlett
Beauty Junior
Bilona
Biola
Black Beauty
Bruce
Bursoto
Cazique
Chalco
Cheresoto
Choice
Climax
Combination
Conquest
Crimson Beauty
Discovery
Donley
Duarte
El Dorado
Eliott
Elsie
Emerald
Endicott
Epoch
Etopa
Excelsior
Ezapatan
First
Flichinger
Formosa
Funk
Gaviota
Gee Whiz Plumcot
Gigantic
N Glow
Golden
Gonzales
Hammer
Hanska
Happiness
Howe
Howe
Hoyt
Inca
Inkpa
Jewell Carpenter
Juicy
June Twenty-
fourth
Kaga
Kahinta
Supposed parentage
W X A
Si X S X C X Mu
S X A
S X ?
Si X S
CX ?
S X A
S X Si
S X c
Mu X ?
(Si X S X C X
Mu) X Na
I X D
S X A
S X A
S X Ch
S X (Mu X S)?
? X Mu
S X A
S X (Mu X S)
A X S
(S X Si) X ?
(S X Si) X ?
H X A
S X Ch
S X A
H Mi X P. cerasus
•>
S X ?
B X A
B X S
Si X S X C X Mu
S X An V
S X ?
Sp X D
Sp X D
S X A
S X Ch
S X (S X Si)
S X Mu
A X ?
S X ?
A X Si
Si X A
S X A
Si X S X C X Mu
S X ?
S X C
B X 8
S X A
SXH
S X Si
D X S
S X A
S X ?
Variety
Kiowa
La Crescent
Loring Prize
Los Gatos
Mammoth
Marianna
May Beauty
Maynard
Methley
Milton
Minnesota 109
Miracle
Monitor
Mound
Mrs. Bruce
Munsou
Nona
Omaha
Opata
Patten's XX
Phoebe
Prize
Reagen
Red Ball
Red Wing
Roadside
Russian hybrid
Sacramento
Sansoto
Sapa
Shiro
Six Weeks
Solano
P. I. 32671
P. I. 32673
Stella
Sweetheart
Tan wick
Terrell
Theo. Williams
Thunder Cloud
Toka
Tokata
Tonka
Underwood
Upright
Vesuvius
Wachampa
Waneta
Waugh
Wickson
Wilma
Winona
Zulu
MISCELLANEOUS SPECIES, NO NAMED VARIETIES
Primus alleghaniensis P. davidiana P. mexicana
P. besseyi P. fremonti P- mira
1 Key to species of parents:
A=Prunus americana
An V = P. anguslifotia var. varians
B=P. besseyi
C=P. cerasifera
Ch=Ohickasaw plum
D=P. domestka
H=P. hortulana
H Mi=P. hortulana var. mineri
I=P. insititia
Ma=.P. maritima
Ma=?. munsoniana
N=P. nigra
Na=Native plum
S=P. salicina
Si=P. simonii
Sp=P. spinosa
W=P. watsoni
? = Species unknown
724
YEARBOOK, 1937
CHERRIES
The cherry is another very important stone fruit, although it is not
grown so extensively in the United States as the peach and the plum.
The varieties in which we are interested for their value as edible fruit
belong to two groups, the sweet and the sour. Varieties of the former
Figure 15. — Eight-year-old trees of Napoleon sweet cherry (Prunus avium).
group are used principally for fresh-fruit dessert, while those of the
latter make up the great bulk of the frozen and canned cherries
of commerce for use in bakeries, restaurants, and homes for pies,
preserves, and sauce. In fact, so important is their use for pies
that this group of sour varieties is frequently referred to as pie
cherries.
Unfortunately, our present-day cherry varieties are not so widely
adapted over this country as we should like to have them. While the
sweet cherry trees are as hardy in wood as the peach, they do not re-
cover so well from winter injury. They blossom early in the spring,
and the flowers are very susceptible to cold and frost injury. The
sour cherry tree is as hardy as some apple varieties, but its blossoms
are also quite tender to cold, and crops are frequently lost by spring
frosts. In more southern latitudes in this country the trees do not
thrive in the hot, dry summers, and in the more humid regions the
fruits are very susceptible to brown rot. Chiefly because of special
climatic requirements, the principal commercial production of sour
cherries is limited to districts along the Great Lakes in the East, and
of the sweet cherry varieties to the Pacific and Intcrmountain States
of the West.
STONE FRUITS
Classification of Cherries
725
All varieties of cultivated cherry belong to two species (8, 18). The
sweet cherries, Prunus avium L., (fig. 15) are tall trees with few or no
suckers from the roots and with leaves downy on the under side. The
sour cherries, Prunus cerasus L., (figs. 16 and 17) are small trees with
many suckers from the roots and with fruit sour to bitter in taste.
Figure 16. — Six-year-old trees of the Montmorency variety of sour cherry
(Prunus cerasus).
Wild forms of the sweet cherry found growing in this country and in
Europe are also called mazzard, bird, and wfld sweet cherry. Some
of these have escaped from cultivation.
The native habitat of the sweet cherry species is in southern and
central Europe and Asia Minor. This species has been divided by
botanists into different groups, but because of hybridization among
the varieties it is rather difficult in many cases to classify them. Sweet
cherries with soft, tender flesh form one group, known by pomologists
under the French group name guigne or the English gean. These are
also known as the heart cherries. These sweet, soft-fruited cherries
may again be divided into dark-colored varieties with reddish juice,
and light-colored varieties with colorless juice. Among the light-
colored gean varieties are Coe, Ida, Elton, and Wood. Dark-colored
ones are represented by Black Tartarian (fig. 18) and Early Purple.
The second group is distinguished by the firm, crisp flesh of the fruits
and is referred to as the bigarreaus. Windsor, Republican, Bing,
and Lambert are representative varieties of the black type, while light
types are Yellow Spanish and Napoleon (fig. 15).
726
YEARBOOK, 1937
The native habitat of Prunus cerasus seems to be close to that of
P. avium in the region about the Caspian Sea to western Anatolia.
De Candolle concludes that P. avium extended westward more rapidly
and was the first to become naturalized. Like the sweet cherry, the
sour cherry is also divided into groups based on the color of the juice.
Cherries with colorless juice are the amarelles, consisting of pale-red
to red fruits more or less flattened at the ends (fig. 19). Common
• v ■
.k <
■A
Figure 17. — Mature irces of Montmorency cherry in bloom. This is the important
sour cherry of commerce grown in the United States.
representatives of this group are Early Richmond and Montmorency
(figs. 16 and 17). The second group called the morellos, contains
varieties with very dark round to oval fruits and flesh with reddish
juice. Typical varieties of this group are English Morello, Ostheim,
and Olivet. A third type in the species is the marasca cherry, from
which is made maraschino, a liqueur used in Europe and the United
States in the manufacture of maraschino cherries. The marasca
cherry is a native of the Province of Dalmatia, Yugoslavia, where the
trees grow wild. The fruits of the marasca varieties are much smaller
and darker and somewhat more acid than the common sour cherry.
In the United States at the present time some varieties of sweet cherry
such as Napoleon, and some sour varieties, are being used for making
maraschino cherries.
The duke cherries (fig. 20) are intermediate in type and have
sometimes been referred to Prunus avium, but more recently have
been considered to be hybrids between P. avium and P. cerasus.
In France they are called royals. May Duke, perhaps one of the
oldest varieties grown in the United States, Reine Hortense, and Late
Duke are important varieties of this group. In the duke cherries
STONE FRUITS
727
many characteristics of fruit, skin, flesh, juice color, and flavor,
as well as of tree growth, are intermediate between the sweets and
sours.
Three other species of cherry that have been used by breeders are
the Nanking or bush cherry, Prunus tomentosa Thunb., an inhabitant
of central Asia; the sand cherry, P. pumila L., of the shores and
Figure 18. — Sweet cherries are more or less heart-shaped and are sometimes referred to
as heart cherries. Black Tartarian, shown above, is a variety of the gean type with
dark flesh and reddish juice. The bigarreau type is similar in appearance but has
firm flesh.
beaches of the eastern United States; and the western sand cherry or
Bessey cherry, P. besseyi Bailey, of the western United States.
In addition to the wild sweet or mazzard cherry, two other species
are important from the standpoint of stocks on which to bud or graft
varieties for propagation. These are the small wild, inedible sour
cherry of southern Europe, Prunus mahaleb L., known as the mahaleb
cherry, and the small wild red or pin cherry of the Northern States
and Canada, P. pensylvanica L. f.
Attempts have also been made to locate pleasant-flavored strains
of the chokecherry, Prunus virginiana L. Some strains are quite
inedible until fully ripe.
Objectives in Cherry Breeding
One of the main objectives in cherry breeding is the production of
high-quality sweet varieties that will prove more hardy in tree and
blossom characters than many of those now available for planting.
The production of such a delicious fruit as the sweet cherry is now
728
YEARBOOK, 193 7
limited to a very few regions of this country. Even in those
regions where it can be grown there is need for firm-fleshed vari-
eties that do not crack and that will ripen over a long season. At
the present time we have no firm-fleshed early-ripening varieties of
the bigarreau type. The unsatisfactory Amiability and germination of
seed of early-ripening varieties impede progress in this direction at
the present time.
In obtaining varieties that will be suited to regions where moderately
low winter temperatures prevail, the matter of understocks may be of
first importance. The chief limiting factor in growing hardy cherries
Figure 19. — Sour cherries of the amarelle group, including pale red to red types with
colorless juice: A, Early Richmond; B, Saint Medard.
in the northern Great Plains area, as well as in certain other parts of the
United States, is the relative tenderness of some mahaleb and mazzard
stocks used in propagation. Selection of better understocks that will
prove more cold-resistant and more widely adapted than those in
present use is worthy of further investigation. Selections of native
cherries that appear to be better adapted to various soil and climatic
conditions, such as hardier strains of our native mazzard and mahaleb
stocks, may prove fruitful of results {21). Cherries are not grown
at the present time in the vast area comprising the southern part of
the United States, principally because of the susceptibility of our
available varieties to certain diseases. There is need for the develop-
ment of disease-resistant varieties for this region.
More genetic and cytological studies are needed, particularly of
hybrids between the sweet and sour varieties, as a basis for more
intelligent choice of desirable parents. Some of the duke varieties
STONE FRUITS
729
arc very excellent cherries but they are not highly productive.
Methods of inducing polyploidy in order to obtain greater fertility
in cherries lias received little attention.
Methods of Chekry Breeding;
The methods used in breeding new varieties of cherry are not
different from those already discussed for the peach and the plum.
Since all of the important varieties of Prunus avium have been shown
to be self-unfruitful {28, 80) emasculation is unnecessary, but with
(he sour and duke varieties the blossoms must be emasculated.
ligurc 20.— Eight-year-old trees of the May Duke variety of the duke group of cherries
One of the important problems confronting the cherry breeder at
present is to find methods for growing the seeds of early-ripening
varieties. T
Improvement in Varieties
Breeding of new varieties of cherries does not seem to have attracted
the interest of private breeders to the extent noted with peaches and
plums. Interest has always been maintained in a search for new
varieties, but progress in obtaining them has been slow. The failure
to develop new varieties may be due partly to the fact that the cherry
is not at home over such a large area of this country as the peach and
the plum. The tenderness of the sweet cherry (Prunus avium)
varieties, with the resulting loss of trees during cold winters, has
largely limited their culture to the more protected aieas along the
Great Lakes and to the Pacific and Intermountain States of the West.
The failure to obtain new varieties, particularly the sweet sorts, may
also be due to the failure of the seed to grow.
;.;s!)(ii
-41 ++
730 YEARBOOK, 1937
The success obtained by two private breeders is worthy of mention.
The pioneer breeding work of the brothers Henderson and Seth
Lewelling in Oregon dates back to 1848 (18). In that year Henderson
Lewelling carried an assortment of varieties of peach, apple, pear,
plum, and cherry by wagon from Iowa to Oregon. These were
planted in Milwaukie, Oreg., as a source of material for nursery and
variety-improvement work. One of the most important varieties of
cherry in this collection was the Napoleon. Apparently the tag had
been lost, and the variety was renamed the Royal Ann, the name by
which it is known in the Pacific Coast States today. From tins stock
of Royal Ann and other cherries, three important new varieties of
the black bigarreau type were developed, Republican, Lambert, and
Bing. Republican, possibly a cross of Napoleon and Black Tartarian,
originated as a seedling in Seth Lewelling's orchard in 1860. Lambert
originated as a seedling under a tree of Napoleon planted by Lewelling
in 1848. From a seed of Napoleon planted in 1875 in Milwaukie,
Seth Lewelling grew the promising seedling that later he called Bing.
These excellent varieties developed by the Lewelling brothers laid
the foundation for the present cherry industry in the Pacific North-
west as well as in California. The Bing, Lambert, Republican, and
Napoleon are at the present time the leading commercial varieties of
sweet cherry in this region.
At about the time that the Lewellings were working on the develop-
ment of cherry varieties in Oregon, P. J. Kirkland, of Cleveland,
Ohio, was engaged in similar work for the eastern United States.
Varieties introduced by Kirkland that have been grown and are still
being grown to some extent are the soft-fleshed sweet varieties Black
Hawk, Kirkland, and Rockport.
In view of the results obtained by these men it is rather surprising
that no enterprising breeder has become interested in more recent
times in searching for better varieties and types of sweet cherries
adapted to this country.
Cherry Breeding in the United States
The New York (State) Agricultural Experiment Station at Geneva
has done the most work on cherry breeding in recent years. The first
crosses were made in 1911. To date, about 1,200 seedlings have been
planted for fruiting, and in addition there are a few hundred in the
nursery for future planting. Sixty-two different sweet, sour, and duke
varieties and a few seedlings have been used in the breeding studies.
The varieties used most extensively were Abesse d'Oignies 33 times,
Abundance 47, Bing 57, Burbank 9, Coe 16, Early Rivers 35, Early
Purple 9, English Morello 46, Elton 41, Emperor Francis 45, Early
Richmond 21, Giant 82, Gil Peck 15, Hedelfingen (Geante d'Hedel-
fingen) 27, Ida 12, Kirtland 50, Knight 10, Ludwig 27, Lambert 81,
Lyons 58, May Duke 72, Montmorency 73, Napoleon 103, Ostheim
26, Olivet 14, Oswego 11, Reine Hortense 25, Royal Duke 9, Republi-
can 32, Schrecken 30, Seneca 74, Schmidt 74, Windsor 59, Wood 24,
and Yellow Spanish 54.
Unfortunately, many cherry seeds failed to germinate, and conse-
quently from thousands of seeds comparatively few trees were obtained.
STONE FRUITS 731
The seeds of early varieties were nearly 100 percent nonviable. The
Seneca, a very early black sweet cherry, was produced at the Geneva
station by crossing an early unknown sweet with the Early Purple.
This variety originated in 1911 and was sent out for trial in 1924.
The only other seedling that has been named was derived from a cross
made in 1925 between Napoleon and Giant. This seedling was named
Gil Peck upon request of the Indian tribes of New York, who were
very fond of the late Gilbert TV. Peck, a Cornell extension worker in
pomology. The Gil Peck was introduced in 1926.
The objectives of the work in New York have been the production
of firm-flesh sweet cherries that do not crack or rot and that ripen from
early to late season. To secure lateness, large-fruited varieties were
crossed with Abundance and with a small, very late, firm-flesh cherry
called Oswego. Late-blooming mazzards have also been used in order
to secure later blooming varieties that may escape late spring freezes.
In addition to fruit of good quality for commercial purposes, pro-
ductive hardy trees have been given consideration in this work.
Little work has been done with the sour (Prunus ceranus) group of
cherry, because the present commercial varieties, Montmorency and
Early Richmond, have been found fairly satisfactory for New York.
The production of desirable duke cherries has also been given considera-
tion, inasmuch as a productive high-quality duke would doubtless
meet with favor among cherry producers and consumers.
In South Dakota, N. E. Hansen has been actively engaged since
1900 in breeding cherries suited to the west north central States. He
has made many crosses, using the western sand cherry, Prunus besseyi,
and other species of Prunus. The sweet cherries, P. avium, which
are raised in the Eastern States and so extensively on the Pacific coast,
arc not hardy in the northern prairie States. The sour cherries, P.
cerasus, are much hardier than the sweets, but they are not generally
planted in this region. The Early Richmond and some other sour
varieties are grown' to a limited extent in the southern part of the
State. Attempts to hybridize sweet and sour varieties with the
native cherries have not been successful.
The following have been developed and introduced:
Select South Dakota sand cherries (Prunus besseyi): Sioux, Tomahawk, and
S. Dak. No. 5.
Sand cherry X Japanese plum: Sapa, Wachampa, Etopa, Eyami, Enopa,
Ezaptan (sand cherry X Burbank Sultan plum), Opata, Owanka, Okiya, Cikana
(sand cherry X Gold plum), Skuya, Wohanka, Wakapa (probably sand cherry
X unknown Japanese plum).
Sand cherry X native plum: Cheresoto, Sansoto (sand cherry X Dc Soto
plum).
Sand cherry X plum: Champa (sand cherry hybrid, a seedling of Sioux open-
pollinated), Oka (seedling of Champa open-pollinated, probably with Japanese
plum).
Sand cherry X Purple-leaf Persian plum: Stanapa (purple-leaved, semi-
dwarf), Cistena (purple-leaved, dwarf).
Sand cherry X European apricot: Yuksa (sand cherry X New Large apricot).
At the Iowa Agricultural Experiment Station cherry-breeding work
is being carried on by utilizing greenhouse-grown trees in the same
way as in the work at this station with plums and peaches. The
varieties consist of six species of Prunus, namely, avium, cerasus,
732 YEARBOOK, 1937
besseyi, japonica Thunb., tomentosa, and cajruli Cav. Trees of the
following crosses are being grown in tlie nursery: Sapa plum (P. salicina
Lindl. X P- besseyi) X Gold cherry (P. avium) ; P. serotina Ehrh. X P.
capuli, and Zumbra X P. tomentosa. The object of this work is to
obtain varieties of cherry hardy for Iowa and suitable for the Great
Plains region.
At the North Dakota Agricultural Experiment Station, work on
cherry breeding is carried on with objectives similar to those in South
Dakota and Iowa. The Cooper sand cherry hybrid was introduced
in 1935. Because of good quality of fruit and hardiness of tree, it is
considered a substitute for the sweet cherry in that State.
In past years about 400 seedlings of open-pollinated Compass
cherry have been grown. Only one seedling had horticultural
value. About 500 chokecherry selections have been grown, and
from this work variety improvement seems possible from the use
of these cherries as parents. Fifty Ft seedlings were obtained from
crosses made in 1926 of chokecherry X P. maackii Rupr. These
seedlings are also of genetic interest and are under study. Seedlings
of hardy Russian sorts and of open-pollinated Anoka are also being
grown.
At the United States Northern Great Plains Field Station at
Mandan, N. Dak., sour and sweet varieties of cherries have been
crossed with pin cherries (Prunus pensylvanica) , western sand cherries
(P. besseyi), Nanking cherries (P. tomentosa), and chokecherries.
Seeds have been produced, but in most cases they failed to grow.
One tree, a cross between Wragg and pin cherry, seems to be fairly
drought-resistant and hardy. It blooms profusely but does not set
fruit, probably because of self-unfruitfulncss.
Several hundred pin cherry seedlings have borne fruit, but none has
been good enough to select.
Several thousand western sand cherry seedlings have been grown.
This hardy native fruit shows a decided and varied response to cul-
tivation; there are marked variations in habit of growth and in size
and quality of the fruit. A number of promising selections have been
made and propagated for further testing. This fruit has also been
used in crossing with plums and Nanking cherries. Some of the latter
crosses are bearing, and both fruit and bush characteristics are inter-
mediate between the western sand cherry and the Nanking cherry.
Second-generation seedlings have been grown.
Large numbers of chokecherry seedlings have been grown, and while
they show considerable variation, no real "chokeless" seedling, i. e.,
entirely nonastringent, has been found. A few of the best have been
propagated on Prunus maackii stock for further testing.
Thousands of seedlings of the Nanking cherry have been fruited in
the testing blocks. This fruit is not entirely hardy and tends to be a
shy bearer. It has been used in crossing with standard varieties of
cherries, the western sand cherry, and plums. The only viable seeds
obtained were from the western sand cherry crosses.
In addition to the breeding work at the various institutions, exten-
sive variety collections are located in a number of States where breed-
ing material may be obtained. Some of these are the New York
(State) Agricultural Experiment Station, the Ohio Agricultural Experi-
STONE FRUITS 733
ment Station at Wooster, the Colorado State College at Fort Collins,
the Utah Agricultural Experiment Station at Ogden, the California
Agricultural Experiment Station at Davis, and the Oregon Agricultural
Experiment Station at Corvallis.
Cherry Breeding in C*n.4da
Cherry-breeding work at the Horticultural Experiment Station
at Vineland, Ontario, Canada, was begun in 1915 and has been
continued up to the present time. During the period 1915 to 1935,
2,587 seedlings were obtained and planted for study. These seed-
lings were from 27 variety crssoes and 27 open pollinations. Sixteen
have been selected as having horticultural value. Two hundred
and eighty-one seedlings were obtained from crosses made in 1931,
using Bing as the seed parent and Black Tartarian, Napoleon, and
Victor as pollen parents, to obtain large, nonsplitting, black varie-
ties. From crosses made in 1935, 1,040 seedlings have been obtained
from Hedelfingen as seed parent and Black Tartarian, Bing,
Victor, and Windsor as pollen parents, with the same object in
view.
From the early cherry-breeding work the Victor variety was intro-
duced in 1935. This variety was a selection from seed of opon-
pollinated Windsor, which was collected in 1916 by F. S. Reeves. It
is a large, attractive white cherry. Approximately 4,000 trees of this
variety have been planted in southern Ontario.
Self-Fertility in Cherry Varieties
Gardner (14), in 1911, working in Oregon, failed to get a set of fruit
from selling 11 varieties of sweet cherry. In 1912 he attempted to
intercross Bing, Lambert, and Napoleon. These varieties proved to
be not only self-incompatible, but incompatible with each other, that
is, they would not set fruit when selfcd or when cross-pollinated among
themselves. In orchards where Napoleon was interplanted with
Republican, and away from the influence of other varieties, the Napo-
leon set a frill crop. The same was true where Lambert and Bing were
interplanted with Black Tartarian.
The results of early cherry pollination work from 1911 to 1913 in
Oregon, as well as later work in that State and in California, show
that all varieties of sweet cherry tested were self-incompatible.
Republican, Black Tartarian, Coe, Early Purple, Elton, Knight,
Major, Francis, May Duke, Rockport, Waterhouse, Willamette,
Windsor, and Wood were all self-incompatible. Republican and Black
Tartarian were found to be good pollinizers for all the varieties. They,
of course, do not set fruit when selfed.
Crane and Lawrence, working in England, have tested 33 varieties
and found all of them to be self -in compatible. Important self- and
cross-incompatible varieties were Black Eagle, Early Rivers, Knight
(Knight's Early Black), and Bedford Prolific, while among cross-
compatible varieties were Black Tartarian, Schmidt, Wood, and
Windsor.
For all practical purposes, therefore, we must consider all true
sweet-cherry varieties of Prunus avium to be self-unfruitful, that is,
734 YEARBOOK, 1937
no fruit will set from blossoms pollinated with their own pollen, since
fertilization will not take place. The genetic explanation of self-
incompatibility of style and pollen and its relation to failure of fruit-
to set has already been discussed in the section on plums.
Types of Sterility
Nearly all of the varieties of sweet cherries fail to set fruit
when the flowers are pollinated with their own pollen. They are
therefore said to be self-sterile. However, the pollen grains and
egg cells of these varieties are functional, for the pollen will grow
when placed on the stigma of another variety, and in like manner
the egg cell will develop if fertilized with pollen of another variety.
With most of the stone fruits fertilization is required before the
fruit will develop, and a variety that does not set fruit because of
the failure of its own pollen to effect fertilization of the flowers is said
to be self -unfruitful.
Strictly speaking, sterility may be due to three causes (28): (1)
Flowers may be sterile because of their morphological development.
Failure of the anthers or pistils, or both, to develop, and failure to
develop viable pollen or functional egg cells, may result in nonfruit-
fulness. It is recognized that such situations may be due to genetic
causes. (2) Sterility may also be physiological. The pollen grains and
egg cells may be normal; fertilization is effected, but the embryo does
not grow because of certain nutritional disturbances. (3) Sterility
may be due to incompatibility. In this case the pollen grains are nor-
mal and will develop in the style of other varieties and bring about
fertilization of the ovules, but they will not function in the style
of the flower of the same variety. It is this latter type of sterility that
is most frequently encountered in the stone fruits. Nearly all of the
sweet cherry varieties are self -unfruitful because of incompatibility.
Varieties such as Napoleon, Windsor, and Black Tartarian will not set
fruit when the flowers of any one of them are pollinated with its own
pollen. If, however, Black Tartarian pollen is applied to Napoleon
or Windsor, a large percentage of the flowers will set fruit. Likewise,
if Windsor pollen is applied to Napoleon or Black Tartarian, fruit-
setting will occur.
The genetic basis of incompatibility has already been discussed in
the section under plums.
Genetic and Cytologic*.!, Studies With Cherries '°
In contrast to the sweet cherries, varieties of sour cherries are self-
fertile, and the pollen of sour varieties will also effectively cause
fruit-setting on sweets.
In duke cherries varying degrees of self-compatibility occur. Crane
and Lawrence (10), working in England at the Johnlnnes Horticul-
tural Institution, have obtained the following percentage of set from
selfing important duke varieties: 9 percent for Late Duke, 3 percent
for Empress Eugenie, 1 percent for May Duke. Keine Hortense set
no fruit. The results obtained from cross-pollinations between sweet,
10 This section is written primarily for students or others professionals- iuterosicd in genetics or
breeding.
STONE FRUITS 735
sour, and (hike cherries have varied considerably. According to Crane
and Lawrence, sweet varieties pollinated by sour varieties generally
produce and mature fruits freely, but from reciprocal pollinations
fruits are less freely formed. In a similar way fruit production is less
when the dukes are pollinated by sweet varieties than when reciprocal
pollinations are made.
We have little knowledge about the origin of our present cherry
varieties. Three varieties produced by Thomas Andrew Knight,
resulting from a cross of a sweet (bigarreau) X May Duke, were
Waterloo, Knight (Knight's Early Black), and Black Eagle, and the
latter two would pass for sweet cherries. In pollination studies to
determine the incompatibility of varieties, it has been observed, both
in this country and in England, that individuals of the same variety
appear to differ in their pollination requirements, and it is possible
that distinct strains of such varieties or types as Black Tartarian or
Napoleon have been propagated. Because of the fact that all varieties
of Prunus avium are self-unfruitful it has been impossible to raise
selfed progeny to study the inheritance of characters and determine
genetic relationships. In studies made at the John Innes Horticul-
tural Institution in England, Crane observed that in selfed families
raised from varieties of P. cerasus, seedlings with P. avium characters
frequently appeared, and in families raised from crosses between
varieties of P. avium, occasional seedlings occurred which showed
marked P. cerasus characters. Furthermore, seedlings in families
raised from P. avium X cerasus resembled the dukes in many char-
acters but not in all.
Cytological investigations of the cherries show the somatic chromo-
some number (2n) in P. avium to be 16, and it is apparently diploid.
In P. cerasus and the dukes the number is 32. Darlington (11), who
has studied the chromosome behavior in a number of cultivated vari-
eties of cherry, considers that P. cerasus is a true tetraploid, not de-
rived simply from P. avium, but one possessing additional elements
probably derived from P. fruticosa Pall., another tetraploid. All of
the sweet cherries examined by Darlington had extra chromosomes
beyond the diploid number. Irregularities occur in chromosome
pairing, but it does not appear that there is any correlation between
the actual chromosome number and the incompatibilities observed in
sweet cherry varieties. Selfed seedlings of sour and duke varieties
showed a chromosome number of 32. In crosses between the sour
and dukes an examination of the progeny shows that the chromosome
number is also 32. However, in crosses between dukes and sweets,
and sours and sweets, the progeny showed the intermediate number
24 in some cases, as we might expect, and in others 32. The culti-
vated duke varieties appear to be tetraploids that have arisen from
hybridization between the diploid sweet cherries and the tetraploid
sours. In experimental studies, however, crosses between some tet-
raploid sours and diploid sweets have yielded seedlings with 24
chromosomes that presumably were triploids and proved to be highly
sterile.
B. R. Nebel, at the New York Agricultural Experiment Station, has
been studying the cytology of interspecific hybrids. From crosses
736
YEARBOOK, 193',
between sour and sweet cherries, 22 triploid first-generation trees
have been obtained, and these are fruiting- on the station grounds. In
attempting to backcross from these hybrids only 1 fruit was obtained
in 700 pollinations. Open-pollinated seed was then used, and this
gave nearly 50 second-generation seedlings. Upon eytological exam-
ination of this second-generation material there appeared to be a
gradation downward in chromosome numbers through loss of some of
the supernumerary chromosomes of the sour species. It is possible
that the second-generation seedlings will, be more fertile than the first-
generation, and that backcrosses with firm-fleshed sweet cherries
will give diploid dukes that are interfertile with sweet cherries. As
already mentioned, if autopolyploidy could be induced, the first-
generation triploids could be made fertile directly and much time
could be saved.
Crane and Lawrence report from their studies of the inheritance
of flesh color in sweet cherries that white is recessive to black. In
crosses between white varieties only white was obtained. Bigarreau
du Schrechen is considered homozygous for black, since in all crosses
where this variety was used as a parent all of the progeny produce
black fruits. Other black varieties, such as Early Rivers, Bedford
Prolific, Black Tartarian types A and B, Late Black, and Schmidt,
are heterozygous for flesh color. It appears, however, that when the
different shades of fruit color are considered, ranging from dark to
white, through various pinks and reds, a number of genes may be
involved in color inheritance.
Selfed sour cherry (morello) varieties with roundish oblate fruit
gave seedlings that yielded occasional long fruits. Kentish Red, a
variety with roundish oblate fruits, gave a progeny that yielded fruits
of variable size and shape.
Table 8.-
Appendix (Cherry)
-Locations of cherry -breeding work and names of workers in the United Stales
and Canada
State or couutry, institution and
location
Early workers
Workers actively engaged at
present
California:
Agricultural Experiment Station, A. A. Hendricksnn. \S". P. | W. P. Tufts, G. L. Philp, E. C.
Tufts, G. I,. Philp. j .Hughe?.
Davis
Iowa:
Agricultural Experiment Station,
Ames.
New York:
Agricultural Experiment Station,
Geneva,
North Dakota:
United States Northern Great Plains
Field Station, Mandan.
Agricultural Experiment Station,
Fargo.
South Dakota:
Agricultural Experiment Station,
Brookings.
Utah:
Agricultural Experiment Station,
Logan.
Canada:
Horticultural Experiment Station,
Vineland, Ontario.
8. A. Heath...
S. A. Beach....
Max I'faemler.
X. E. Hansen.,
T. ,T. Maney.
V. V. Uedricfc. K. Wellington,
G. If. Howe, B. R. Neliel.
\V. V. Baird.
A. 1". Yeager.
N. E. Hansen.
F. M. Coe
F. E. Palmer, O. If. Dickson.
STONE FRUITS
737
Cherry Material at the California Agricultural Experiment
Station, Davis, Calif.11
Prunus tomenlosa:
Var. Bush Cherry (P. I.
36086)
P. pseudocerasus:
Var. Tangsi (P. I.
1 8587) . (Season very
early.)
P. avium:
Abundance
Allen
Bassford
Bauman May
Bedford Prolific
Belle de Drureo
Belle d'Orleans
Best
Biggareau Blanc d'
Espagne
Bigarreau d'ltalie
Bing
Black Oregon
Black Republican
Black Sweet
Black Tartarian
Bohemian
Burbank
Burr's Seedling
Bush Tartarian
California Advance
Centennial
Chapman
Cleveland
Coop's Special
Deacon
Dikeman
Dr. Flvnn
Double White
Downer
Dyehouse
Early Purple Guigne
Earlv Rivers
P. avium — Continued.
Elton
Emperor Francis
Garrafal
Garrafal lo Grand (P. I.
33223)
Giant
Gold
Hcdelfingcn
Hinton
Hoskins
Improved Black Tarta-
rian
Jaboulay
Knight
Koontz Mammoth
La Cima
Lamaurie
Lambert
Late Bing
Lewelling
Long Stem Royal Ann
Long Stemmed Water-
house
Major Francis
Mezei
Napoleon
Ord
Ostheimcr Weiclisel
Oxheart
Paul
Pontiac
Porter's Tartarian
Ramon Oliva
Roe
Royal Stewart-
Savior
Schmidt
Seneca
Sharp
P. avium — Continued.
Shelton
Negro de la Rivera (P.
I. 73456)
Risada de Konter (P. I.
73457)
Thorn) >son
Transcendens Black
Heart
Vaughn
Waterloo Heart
White Carron
Willamette
Windsor
Wood
P. cerasus:
Baldwin
Dyehouse
Early Richmond
English Morello
Homer
Large Montmorency
Montmorency
Nelson
Terry
Vladimir
Wragg
Dukes:
Empress Eugenie
Late Duke
May Duke
Minehin
Noble
Olivet
Reine Hortense
Royal Duke
Hybrids:
New Century. Parent-
age, P. cerasus X (P.
avium X cerasus).
Cherry Varieties at Hie ]\ew York Agricultural Experiment Station,
Geneva, N. Y.
Abbesse d'Oignies
Belle di Barbanti (U. S. D. A.)
Bianco Rosatio di Piemonte (U. S. D. A.)
Bicentenaria (U. S. D. A.)
Bigarreau de Schrecken
Emperor Francis
Garrafal le Grand
Geante d'Hedelfingen (Genua n y ) .
(Synonym of Hedelfhigen.)
Giant
Gil Peck
Grosse Lange Lothkirsclie (Germany).
(Synonym of English Morello.)
Ludwig Bigarreau
Marasca di Verona (U. S. D. A.)
Marasca Moscata (U. S. D. A.)
Nero Grossa di Pimento (U. S. D. A.)
Noir de Guben
Seneca
"This list contains, besides well-known varieties, local selections and other sorts the names of which
cannot well be made at this time to conform to the code of nomenclature.
738 YEARBOOK, 1937
APRICOTS
The apricot is prized by all who like the stone fruits, and when
eaten fresh it is considered by many to be the most delectable of
this group. Unfortunately, however, very few apricots are grown
for fresh fruit in the States east of the Rocky Mountains, and most
people know the flavor of this fruit only from the canned or dried
product. Its production is restricted to a relatively small area in
this country where climatic conditions are favorable. Most varieties
can withstand winter cold as well as peaches, but the blossom buds
develop rapidly under favorable growing temperatures in late winter
after the rest period is over, and the crops are frequently lost from
late freezes and spring frosts.
The commercial production of the apricot (fig. 21) is confined largely
to the Pacific Coast and Intermountain States^ (5, 20). California
leads with a potential average production considerably in excess of
200,000 tons. Of the average crop of 266,000 tons harvested during
the years 1931-33, approximately 76 percent was dried, slightly over
14 percent canned, and about 10 percent was shipped or consumed
locally as fresh fruit. Because of the great perishability of this fruit
and the need for quick handling, fresh apricots are on the market in
the Eastern States for only a short time and their distribution is
limited to large centers of population.
Botany and History of the Apricot
All of the important commercial varieties of apricot grown in this
country today belong to the species Prunus armeniaca L. The name
of the species, like that of the peach, is a geographical misnomer.
The apricot was formerly considered a native of the Caucasus and
Armenia, but later studies suggest that China is its native home. It
is said that Alexander the Great brought the apricot from Armenia
to Greece, whence it was taken to Italy. The Romans cultivated
this fruit, and it is described in the wTitings of Pliny and Dioscorides.
It was later carried to France, and there is mention of its being in
England in Turner's Herbal, published in 1562. The fruit is now
cultivated in all of central and southeastern Asia, and in parts of
southern Europe and northern Africa. There seems to be no mention
of it in the United States until 1720, when it was said to be growing
abundantly in Virginia. It was doubtless among the fruits brought
into southern California early in the eighteenth century by the Mis-
sion Fathers. Its culture spread to the valleys farther north, where
climatic conditions were more congenial. Wickson (33) reports that
Vancouver found a fine orchard of fruits, including apricot, at Santa
Clara in 1792. In 1935, 17 varieties were described as growing in
England. Downing (12, pp. 236-242) names 26 varieties, and the
American Pomological Society (1) lists 11 varieties as growing in the
United States in 1879.
In tree, fruit, and flower characters the apricot seems to be some-
what intermediate between the plum and the peach. The trees are
large and spreading, and in this respect are more like the peach and
some of the Japanese plums. The leaves are broad, heart-shaped,
dark green in color, and held erect on the twigs. The flowers are
STONE FRUITS
739
white, resembling those of the plum in color, but are borne not in
clusters but singly or doubly at a node on very short stems. Like
the peach, the apricot is self-fruitful and will set fruit when its blos-
soms are selfed. The pit is smooth, somewhat like that of the plum,
but broader, somewhat flatter, and more winged. The fruit is nearly
smooth, round to oblong, in some varieties somewhat flattened, and
in general rather more like the peach in shape. The flesh is typically
Figure 21. — Peach and apricot growing constitutes an important industry in California.
The apricot trees, in the immediate foreground, and the peach trees in the rear are a
part of a large orchard with rows 3 miles long.
an attractive yellow to yellowish orange. The kernels of some
varieties are sweet.
The peach, plum, and apricot may be readily intergrafted. The
apricot does well on peach stock, but the peach on apricot stock is not
entirely satisfactory.
In addition to the common apricot (Primus armeniaca), which
comprises all of the commercial varieties grown in this country,
several other species are of interest to the breeder. The black apricot
(P. dasycarpa Ehrh.) has fruits of small size, dark purple or black in
color, and for the most part of inferior quality. The trees more
closely resemble the plum and possess considerable hardiness in wood
and bud.
The Japanese apricot (P. mume Sieb. and Zucc.) is noted princi-
pally for the ornamental character of the trees. The flowers and fruits
also are very attractive.
Types native in other countries have been described as species but
are classed by some authorities as subspecies. The Russian apricot
(/'. xibirica L.), is possibly a strain of the common apricot (P. armeni-
740 YEARBOOK, 1937
aca). Trees of the Russian apricot differ from the common apricot
in bearing smaller fruit of poorer quality. They are considered very
much hardier in their native home, but certain strains brought
into this country have not shown superior hardiness under test.
The trees have a characteristic upright growth habit, are thicklv
branched, and possess more thornlike spurs. The small fruits set in
clusters.
Another probable subspecies, the Manchurian apricot (P. manrf-
schurica Koehne), is a common wild tree in central Chosen. Its fruit
is similar to that of the common apricot, but the leaves differ, and its
bark is thick and corky. This subspecies may be a selected strain of
the common apricot.
The apricot is widely distributed throughout Asia, and a large number
of seedlings have been observed growing wild in various localities.
In China some travelers report the apricot only as a cultivated tree,
but others have found it growing wild in the northern Provinces.
Breeding Material
The apricot is less rich than some of the other stone fruits in species
and horticultural varieties suitable for breeding material. The raw
material consists of many old varieties introduced from England and
France. Among those recognized as of English origin are Blenheim,
Early Moorpark, Moorpark, and Hemskirke. These are all varieties,
of high quality, with the Blenheim maintaining first importance as a
commercial variety. Varieties of French origin are Peach, Oullins
Early, Montgamet, Luizet, and Royal. Royal is the most important
commercial variety of this group. Like the English varieties, all the
French varieties have certain commercial limitations. There is an
excellent opportunity for the apricot breeder to combine their desirable
characters by cross breeding. Work of this kind is already under
way at State and Federal agricultural experiment stations, as will be
pointed out later.
A large number of varieties have been introduced from the Union
of Soviet Socialist Republics, many of these by J. L. Budd, of Iowa.
As a class they are more hardy in bud, later in blossoming, with fruit
of smaller size and poorer quality, but they are very productive.
Some of the more important varieties of this group are Alexander,
Budd, Gibb, Shense (Acme), Superb, and Toyahvale. Little work
has been done in combining the qualities of these hardy sorts, which
some botanists considers separate species (Prunus sibirica), with tlie
commonly grown varieties from western Europe.
In the last half century a number of promising seedlings and strains
of American origin have been selected, but only the Tiltdn ranks with
the older European sorts as an important commercial variety. As
might be expected, most of the American varieties originated in Pacific
Coast States. Among the more important are Newcastle, Alameda
Hemskirke, Routier Peach, Derby Royal, and Sparks Mammoth,
from California. Other varieties of more recent origin are Wenatchee
Moorpark, which has been reported to bo similar to if not identical
with Moorpark, Riland, Gilbert, and Sofia, originating in the State of
Washington. Among other older American varieties are Early Golden
and Superb.
STONE FRUITS 741
The apricot lias been crossed Avitli varieties of plum, particularly
the Japanese plum. Luther Burbank produced a number of seedlings
by crossing the apricot with this plum. Some of the more promising
of these have been introduced under the group name plumcot. Among
the more important are Apex, Corona, Rutland, Silver, and Triumph.
The crosses of apricot with plum have apparently been more,
successful than those with peach. No horticulturally satisfactory
peach-apricot varieties have been reported.
Objectives in Apricot Breeding
If apricot culture is to be extended beyond the present restricted
areas where climatic conditions are favorable, varieties must be de-
veloped that are later in flowering in spring. From material that has
been brought into this country, differences in bud hardiness and in
blooming have been observed. There is need for the introduction of
varieties from countries where apricots are growing and surviving
temperatures as low as those obtaining during the winter months in
this country. Many of these will doubtless prove worthless from the
standpoint of edible fruit quality, but will serve as breeding material
for the development of better varieties. In California considerable
loss results from the dropping of blossom buds of certain varieties.
Varieties that have a short rest period, are needed for those sections
of the country where the winter temperatures are not low. Better
canning, drying, and shipping varieties are also in demand. Evidence
at hand would indicate that the commercial quality of varieties can
be improved by breeding.
There is little information about the development of varieties by
private breeders. A number of chance seedlings have been discovered
by individuals, but it does not appear that any conscious attempt to
select or breed new varieties has been carried on to the extent that it
has with the other stone fruits. It is likely that many who were
interested in better varieties were discouraged in their attempts
because the parent material available for crossing was in itself not
sufficiently hardy.
In the selection of material for breeding, difficulty may be encoun-
tered in establishing the trueness to name of varieties, since the same
variety may be grown in two or more localities under different names.
Some of the varieties representing desirable types are Moorpark,
Royal, Blenheim, Tilton, Montgamct, and some selections of Russian
and Japanese origin. For breeding studies in the eastern United
States, where hardiness is an important factor, varieties should be
used that have been tested and have demonstrated superior hardiness,
such as strains of Russian varieties introduced by Budd, and more
recent importations made by Hansen, of South Dakota, and the
Division of Plant Exploration and Introduction, Bureau of Plant
Industry, United States Department of Agriculture.
Apricot Breeding at State and Federal Stations
Apricot breeding was started at the New York (State) Agricultural
Experiment Station in 1922. Eighteen varieties, one seedling, and
two P. I. numbered seedlings have been used. Eighty-four seedlings
derived from definite crosses, 1,424 from open cross-pollination, and 9
742 YEARBOOK, 1937
from self-pollination have been set in the orchard for fruiting. Varie-
ties used most extensively have been Alexis 6 times, Doty (a local
seedling) 15, Downing (late blooming) 5, Montgamet 6, Oullins Early
13, St. Ambrose 5, and Toyahvale 5. A seedling grown from a seed
imported by the Department of Agriculture as P. I. 34265 has been
considered worthy of a name. This variety was temporarily called
"Frascati", as the seed was thought to have been imported from the
vicinity of Frascati, Italy, but more recently it has been given the
name Geneva.
At the North Dakota station apricot breeding work w^as started in
1924 in an attempt to develop varieties of sufficient hardiness to stand
the winters of the northern Great Plains area. Over 2,000 seedlings
are being grown and studied for their hardiness and quality of fruit.
At the South Dakota station, N. E. Hansen has been propa-
gating trees from seeds collected by him in northern Manchuria in
1924. The fruits were taken from trees growing in localities reported
to have minimum temperatures of —47° F. Twenty-three selec-
tions, called the Manchu group, have been propagated for test.
Additional collections made in 1934 in eastern Siberia for propagation
at Brookings are expected to give seedlings with greater hardiness than
the Manchu.
Breeding work at the California station at Davis, Calif., was
started in 1930. The objective is the development of varieties of
high quality suitable for shipping as fresh fruits, canning, and drying,
but lacking some of the faults of the old varieties now grown com-
mercially. Varieties tised as pollen and seed parents have been Tilton,
Royal, Hemskirke, Blenheim, St. Ambroise, Peach, Newcastle, Moor-
park, Oullins Early, and in addition strains of Moorpark and Hems-
kirke. In the seasons of 1933 and 1934, one seedling each was
obtained from the following interspecies crosses: Royal X Prunus
pseudocerasus, P. mume X Royal, Pringle Late X Rutland plumcot,
Diamond Jubilee nectarine X Royal, and Lovell peach X Royal.
From the crosses made during 1930-35 there are at the present time
over 2,000 seedlings growing in the orchard.
This material should provide a sufficiently large progeny for genetic
studies of the varieties used as parents and serve as a source of superior
seedlings that may be worthy of naming. A list of the crosses and the
number of seedlings in each cross, as well as a list of varieties now
being grown, is given in the appendix to this section.
At Palo Alto, Calif., apricot breeding by the United States Depart-
ment of Agriculture in cooperation with Leland Stanford Junior
University has been in progress since 1922. A search for varieties of
high quality that would prove more satisfactory for the established
apricot districts has been the main objective of this work. About 60
promising hybrids have been selected for further studying and testing.
The more common varieties, such as Blenheim, Tilton, Moorpark,
Royal, Newcastle, and Hemskirke, have been used as seed and pollen
parents : and in addition the less common varieties Bergetti, Mont-
gamet, McKinley, Luizet, Bremner, and Sparks. Hybrids of these
varieties have been recrossed, and other combinations have been made
by using promising parents introduced from southern Europe, Africa,
and Asia in an effort to obtain certain desirable characteristics in the
STONE FRUITS 743
progeny. In this material from abroad are included Giallo di Tortona,
Tunis seedlings, Japanese seedling 26018, Sardinian, P. I. 28954, and
P. I. 34272.
A list of the hybrids selected with the parentage and the years the
crosses were made is given in the appendix.
Apricot Breeding in Other Countries
A program of apricot breeding has been under way for some time
under the supervision of the Department of Agriculture at the Yanco
Experiment Farm, Sydney, New South Wales. The work has for its
object the production of superior canning varieties, particularly later
varieties than Trevatt, to extend the season and thus close the gap of
ripening between the latest canning apricots and the earliest canning
peaches. Importations of seed have been made from Palestine, Iraq,
Syria, and Morocco, and from this material seedlings are now being
grown. The varieties used in the crosses and for open pollination are
Alsace, Bouche Peche, Mansfield, Moorpark, Lossie Blenheim, Tilton,
Campbellfield, Bathurst, Trevatt, Newcastle, and Rose de Vaucluse.
From results obtained to date, Moorpark seems to be the best parent
variety for giving a useful range of seedlings, while Trevatt cross-
bred seedlings have better general quality. A Moorpark X Bouche
Peche seedling is being propagated for orchard trial.
In Morocco, work is being carried on at the new State station at
Ain Taoujdat, especially designed for research in horticultural
genetics. New varieties of high quality are being sought for by
hybridization. Ten distinct forms of native apricot (mechmecli)
have been studied comparatively since 1934 for their value as stocks.
Superiority has been shown by E. F. 136, 137, and 139.
Genetic and Cytological Studies With Apricots
There is little published information dealing with the genetics of
hybrid progenies of apricot varieties and species.
Cytological studies have been made at the agricultural experiment
stations of New York and California, and all apricot varieties exam-
ined thus far have 16 as the diploid (2n) number of chromosomes,
which is the number found in sweet cherry, peach, and some species
of plum. At the New York (State) Agricultural Experiment Station,
chromosome numbers in exceptionally vigorous seedlings and also
in abnormal seedlings from embryo cultures have been counted, but
in a total of about 50 cases no deviation from the regular diploid type
was found. Unsuccessful attempts have been made to induce poly-
ploidy by selecting giant pollen grains under the microscope, mounting
them on hairs, and applying them to the stigmas of flowers. Radiation
experiments with stem meristem have also failed. This work is
being continued, and other methods to induce polyploidy in apricots
are being tried.
Cytological investigations are under way at the California station
to determine the true hybridity of the plumcots. This is important
in breeding work, to determine whether the characters in segregation
will behave as true hybrids or whether they will behave separately
as plums or apricots.
744
YEARBOOK, 193 7
Appendix (Apricot)
Table 9. — Locations of apricot-breeding work and names of workers in the United States
and other countries
State or couutry, and institution
Location
Workers actively engaged
California:
Agricultural Experiment Station Davis . .
U. S. Department of Agriculture ' do
Do : Palo Alto
New Y'jrk: Agricultural Experiment Sta- ! Geneva ...
tion.
North Dakota:
Agricultural Experiment Station j largo .
U. S. Department of Agriculture . Mandan... ._
South Dakota: Agricultural Experiment | Brookings
Station.
Utah: Agricultural Experiment Station... Logan
New South Wales: Department of Agri- | Sydney .
culture.
Morocco: Experimental Laboratory.. I Aiu Taoujdaf. .
.: W. P. Tufts, T.. C. Hughes.
-! J. II. King.
. W.F.Wight,.
.1 R. Wellington, Olav "liinset.
A. F. Yeager.
W. P. Baird.
N. E. Hansen.
F. M. Coc.
H. Wenhol?..
Ch. Miedzyrzeohi.
Table 10. — Apricot seedlings growing at the California Agricultural
Exj>eriment Station, Davis, Calif. 1
Year
of cross
Seedlings; p„,-»„t<
planted laients
Year j Seedlings
of cross i planted
Parents
Number
Number
1931
72
Tilton X Moorpark.
■ 57
Itoyol X Grace.
.174
Royal X Newcastle.
1932 : 8
St. Ambroise X Tilton.
104
Royal X Hemskirke.
22
St. Ambroise X Moorpark.
228
Royal X Moorpark.
8
Peach X P. I. 38281.
230
Royal X Tilton.
4
Peach X Tilton.
31
Wcnatchce Moorpark X Tilton. ]■ 43
Wenatchee Moorpark x Oul-
2
\\ enatchee Moorpark X Roval.
.
lins Early.
21
Hemskirke X Tilton.
1
Derby X Alameda Hemskirke.
6
Hemskirke X Moorpark.
, 1933
2
Newcastle X Peach.
149
Hersey Moorpark X Roval.
i
1
Tree (22-1) X Peach.
33
Blenheim X self.
j
1
Royal X Primus pseudocerams.
7
St. Ambroise X Royal.
I
1
Primus mume X Royal.
93
St. Ambroise X Tilton.
1934
1
Pringle Late X Rutland plum-
172
St. Ambroise X Moorpark.
cot.
1932
13
Royal X Peach.
1
Diamond Jubilee nectarine X
10
Royal X M enatchee Moorpark.
Royal.
185
Royal X Oullins Early.
1
Lovell peach x Royal.
25
Royal X Alameda Hemskirke. !■
i Verification of the nomenclature used in this and the following lists lias not been possible in all cases.
Where doubt exists as to the identity of a variety referred to by a name of uncertain validity, no attempt has
been made to bring such name into conformity with the code of nomenclature, as it might later result in
confusion.
Apricot-Breeding Material at the California Agricultural Experiment
Station, Davis, Calif.
Prunus armeniaca:
Alameda Hemskirke
Alexander
Alexis
Bairam Ali
Barry
Beaugo
Bizant Royal
Blackmon
Blenheim
Blush
Bolton
Boulbon
Primus armeniaca — Con.
Brady
Breda
Budd
Burtons Roval Seedling
B. W. Marshall
Catharine
Chinese
Cluster
Colorado
Cream
Crisomelo
Cutler
Prunus armeniaca — Con.
Derby Royal
Di Breda
Early Cluster
Early Golden
Early May
Garlaeh
Giallo di Tortona
Gihb
Gilbert
Great Plains
Giffin Choice
Grosse Peehe
STONE FRUITS
745
Prunus armeniaca — Con.
Gross Blanca Precoce
Harris
Hemskirke
Hersey Moorpark
Janet
Jones
Kaledcn
Knobel Blenheim
Lampasas
Large Early Mont-
gamet
Lewis
Losse Blenheim
Lowe
Luizet
Mammoth White
Maxson
McKiuloy
Meyer Giant
Miner
Mognaga
Montgamet
Moorpark
Murgab
Nellie
Newcastle
New Large Early
Nicholas
Noble
Oullins Earlv
Prunus armeniaca — Con.
Particolare
Paviot
Peach
P. I. 20072
P. I. 28960
P. I. 34265
P. I. 34270
P. I. 38281
Pritigle
Pringle Late
Red Beauty
Poland
Rivers
Rivers Early
Routier Peach
Roval
Rualt
Santa Pe
Sardinian
Sharpe
Shonse (Casaba, Acme,
Yakimenc)
Sloan
Smyrna
Snowball
Sophia
Sparks Mammoth
St. Ambroise
Stella
Prunus armeniaca — Con.
Stephens
Stewart
Sugar
Superb
Tentazione
Thissell
Thompson Earlv
Tilton
Toyahvale
Trevatt
TJpham No. 1
Upham No. 3
Wenatchee Moorpark
Wiggin
Wilson
Zuccherino di Holub
Prunus armeniaca,
v&T.ansu Maxim.:
Apricot Plum
Prunus dasycarpa:
Black
Florizan
Prunus dasycarpaTXo. 13
Prunus mume:
Bongoume
Double Flowering
Japanese (P. I. 45523)
Prunus brigantiaca Vili.
Prunus sibirica
Apricot Hybrids Produced and Under Test at Palo Alto, Calif., in Coopera'
tion Between the United Slates Department of Agriculture and
Leland Stanford Junior University
YeaT Parents of hybrids
1923 Bergetti X Montgamet.
1931 (Bergetti X Montgamet 30-37 ' ) X (Blenheim X Tilton 27-50).
1934 (Bergetti X Montgamet 30-36) X Bremner.
1932 (Bergetti X Montgamet 30-36) X (Moorpark X Blenheim 28-52).
1923 Blenheim X McKinlev.
1935 (Blenheim X McKinlev 27-21) X (Blenheim X Moorpark 12-58).
1920 Blenheim X Moorpark.
1932 (Blenheim X Moorpark 12-55) X Japanese seedling 20-19.
1932 (Blenheim X Moorpark 12-59) X (Sparks X Blenheim 37-60).
1935 (Blenheim X Moorpark 12-58) X 75222 Tunis 27-70.
1935 Blenheim X (Sardinian X Roval 37-56).
1923 Blenheim X Tilton.
1934 (Blenheim X Tilton 27-50) X (Bergetti X Montgamet 30-35) .
1933 (Blenheim X Tilton 28-6) X (Blenheim X Moorpark 12-59).
1934 (Blenheim X Tilton 27-50) X (Blenheim X Tilton 28-6).
1934 (Blenheim X Tilton 28-7) X (Blenheim X 28954 13-20).
1932 (Blenheim X Tilton 27-47) X Bremner.
1931 (Blenheim X Tilton) X Hemskirke.
1935 (Blenheim X Tilton 28-6) X Japanese seedling 20-18.
1932 (Blenheim X Tilton 27-50) X (Moorpark X Blenheim 28-52).
1932 (Blenheim X Tilton 28-6) X (Sparks X Blenheim 37-60).
1933 (Blenheim X Tilton 28-7) X (Blenheim X Tilton 27-50V
1934 (Blenheim X Tilton 27-50) X (34272T2 X Blenheim 12-51).
1921 Blenheim X 28954.
1934 Bremner 9-27 X (Blenheim X 28954 13-26).
1933 Cirio 13-5A X (Blenheim X Moorpark 12-59).
• N timbers following variety name refer to row and tree location of the parent.
138904° — 37 48
746 YEARBOOK, 1937
Year Parents of hybrids
1924 "Crow apricot seedling".
1920 Prunus dasycarpa X Blenheim.
1927 Giallo di Tortona X Moorpark.
1932 Giallo di Fortona X (Moorpark 9-16 X Japanese).
1933 Hemskirke X (Blenheim X Tilton 27-50).
1935 Japanese seedling2 26-18 open 27-340 X (Blenheim X Moorpark 12-58).
1935 Japanese seedling 26-18 X (Sardinian X Royal 37-56).
1923 Luizct X Moorpark.
1931 (Luizct X Moorpark 28-39) X Blenheim.
1923 Moorpark X Blenheim.
1931 (Moorpark X Blenheim 28-52) X (Blenheim X Moorpark 12-56).
1932 (Moorpark X Blenheim 28-42) X (Blenheim X Tilton 28-6).
1935 (Moorpark X Blenheim 28-52) X (Sardinian X Royal 2-25 37-56).
1923 Moorpark X Tilton.
1931 (Moorpark X Tilton 28-13) X Hemskirke.
1933 (Moorpark X Tilton 28-12) X (Moorpark X Blenheim 28-52).
1921 Moorpark X P. I. 28954.
1932 (Moorpark 15-28 X P. I. 28954) X Bremner.
1932 Newcastle II 27-16 X Japanese seedling.
1923 Royal X Blenheim.
1933 Royal X (Blenheim X Tilton 28-6).
1935 Royal X Japanese seedling 26-18.
1923 St. Ambroisc X Luizct.
1931 Sardinian X Japanese seedling.
1925 Sardinian X Royal.
1925 Sparks Mammoth X Blenheim.
1935 (Sparks Mammoth X Blenheim 37-59) X (Blenheim X Moorpark 12-581.
1932 (Sparks Mammoth X Blenheim 37-59) X Bremner.
1923 Tilton X Moorpark.
1933 (Tilton X Moorpark 30-23) X (Blenheim X Tilton 27-48).
1933 Tunis 27-7A X (Moorpark X Blenheim 28-52).
1920 P. I. 34272T2 X Blenheim.
1932 (P. I. 34272 X Blenheim 12-50) X (Sparks Mammoth X Blenheim 37-60).
Apricot Breeding Material at the New York (State) Agricultural Experiment
Station, Geneva, N. Y.
Criscmelo seedling, P. I. Ispharak Kandak (Rue- Ritteuhousc.
34269. sia). Schik-Usbekistan (Rus-
Gcueva. Murgab (P. I. 32834). sia).
Henderson. Mulla-gadai (Russia). Toyahvale.
Paviot (Germany). Ungarishe.
LITERATURE CITED
(1) American Pomological Society.
1880. proceedings op the seventeenth session of the american
POMOLOGICAL SOCIETY . . . 1870. 134 pp., illllS.
(2) Bailey, J. S., and French, A. P.
1933. THE INHERITANCE OF CERTAIN CHARACTERS IN THE PEACH. Amer.
Soc. Ilort. Sci. Proc. (1932) 29: 127-130.
(3) Bailey, L. II.
1892. THE CULTIVATED NATIVE PLUMS AND CHERRIES. N. Y. (Cornell)
Agr. Expt. Sta. Bull. 38, 72 pp., illus.
(4) Blake, M. A., and Connors, C. II.
1936. early results of peach breeding in new jersey. N. J. Agr.
Expt. Sta. Bull. 599, 32 pp., illus.
(5) Coe, F. M.
1934. apricot varieties. Utah Agr. Expt. Sta. Bull. 251, 59 pp., illus.
(6) Connors, C. H.
1918. methods in breeding peaches. Amer. Soe. Hort. Sci. Proc.
(1917) 14: 126-127.
2 "Japanese" variety from John Hock collection at Xiles, Calif. Tree was not labeled, and nothing is
known of its origin.
STONE FRUITS 747
(7) Connors, G. H.
1923. l'EACH BREEDING A SUMMARY OF RESULTS. Amer. SoC. Hort.
Sci. Proc. (1922) 19: 108-1 15.
(8) Crane, M. B.
1921. EXPERIMENTS in breeding plums, with a note on peaches.
Jour. Pomol. 2: 137-159, illus.
(9) —
1923. REPORT ON TESTS OF SELF-STERILITY AND CROSS-INCOMPATIBILITY
IN PLUMS, CHERRIES AND ArPLES AT THE JOHN INNES HORTI-
CULTURAL institution, ii. Jour. Pomol. and Hort. Sci. 3:
67-84, illus.
(10) and Lawrence, W. J. C.
1934. THE GENETICS OF GARDEN PLANTS. 236 pp., illllS. London.
(11) Darltngton, C. D.
1926. on the cytology of the cherries. Brit. Assoc. Adv. Sci. Rept.
Mooting 94: 407-408.
(12) Downing, A. J.
1857. the fruits and fruit trees of America . . . Rov. and corrected
bv Charles Downing. 760 pp., illus. New York.
(13) East, E. M. "
1927. the genetics and physiology of self-sterility in nicotiana.
Hort, Soc. N. Y. Mem. 3: 321-323.
(14) Cardner, V. R.
1913. a preliminary report on the pollination- of the sweet
cherry. Oreg. Agr. Expt. Sta. Bull. 110, 40 pp., illus.
(15) Hansen, N. E.
1927. plant introductions (t025- 1027). S. Dak. Agr. Expt. Sta. Bull.
224, 64 pp., illus.
(16) Hedrick, IJ. P.
1922. cyclopedia of hardy fruits. 370 pp., illus. Now York.
(17) assisted by Howe, G. H., Taylor, O. M., and Tubergex, C. B.
1917. the peaches of new york. N. Y. Agr. Expt. Sta. Rept, 1916,
pt. 2, 541 pp., illus.
(18) • assisted by Howe, G. II., Taylor, O. M., Tubergen, C. B., and
Wellington, II.
1915. the cherries of new york. N. Y. Agr. Expt. Sta. Rept. 1914,
pt. 2, 371 pp., illus.
(19) — ■ assisted by Wellington R., Taylor, O. M., Alderman, W. II.,
and Dorsey, M. J.
1911. the plums of new YORK. N. Y. Agr. Expt. Sta. Rept. 1910, pt.
2, 616 pp., illus.
(20) Henderson, A. H.
1930. apricot growing in California. Calif. Agr. Ext. Cire. 51.
(21) Howk, G. II.
1927. MAZZARD AND MAHALEB ROOTSTOCKS FOE CHERRIES. N. Y. Agr.
Expt. Sta. Bull. 544, 14 pp., illus.
(22) Jones, D. F.
1928. burbank's results with plums. Jour. Heredity 19: 359-371,
illus.
(23) Kraus, E. ,T.
1916. the self-sterility problem. Jour. Heredity 6: 549-557, illus.
(24) Lehmann, E.
1927. the heredity of self-sterility in veronica syriaca. Hort.
Soc. N. Y. Mem. 3: 313-320, illus.
(25) Onderdonk, G.
1888. peach culture in the extreme southwest. U. S. Coramr.
Agr. Ann. Rept. 1887: 648-651.
(26) Palmer, E. F.
1923. solving the fruit, grower's problems by plant breeding.
Amer. Soc. Hort. Sci. Proc. (1922) 19: 115-124.
(27) Rivers, H. S.
1907. the cross-breeding of peaches and nectarines. 3d Internatl.
Conf. Genetics, London, 1906, pp. 463-467.
748 YEARBOOK, 1937
(28) Schuster, C. E.
1925. POLLINATION AND GROWING OF THE CHERRY. OrCg. Agl\ Expt.
Sta. Bull. 212, 40 pp., illus.
(29) Shamel, A. D., Pomeroy, C. S., and Harmon, F. N.
1932. bud variation in peaches. U. S. Dept. Agr. Circ. 212, 22 pp.,
illus.
(30) Tufts, W. P., and Philp, G. L.
1925. poli.tnation of the sweet chbrky. Calif. Agr. Expt. Sta. Bull.
385, 28 pp., illus.
(31) Weldon, G. P.
1924. instability of peach varieties. Jour. Heredity 15: 86-90, illus.
(32) Wellington, R.
1927. an experiment in breeding plums. N. Y. State Agr. Expt.
Sta. Tech. Bull. 127, 61 pp.
(33) Wickson, E. J.
1921. CALIFORNIA FRUITS AND BOW TO GROW THEM . . . Ed. 9, fully reV.,
508 pp., illus. San Francisco.
(34) Wight, W. F.
1915. native American species of pitUNus. U. S. Dept. Agr. Bull. 179,
75 pp., illus.
IMPROVEMENT OF SUBTROPICAL
FRUIT CROPS: CITRUS
HAMILTON P. TRAUB, Senior Horticulturist
T. RALPH ROBINSON, Senior Physiolo-
gist Division of Fruit and Vegetable Crops
and Diseases, Bureau of Plant Industrv
MOB.E than half of the 13 fruit crops known to have been cultivated
longer than 4,000 years, according to the researches of De Candolle
(7)1, are tropical and subtropical fruits — mango, olive, fig, date,
banana, jujube, and pomegranate. The citrus fruits as a group, the
lychee, and the persimmon have been cultivated for thousands of years
in the Orient; the avocado and papaya were important food crops
in the American Tropics and subtropics long before the discovery
of the New World. Other types, such as the pineapple, granadilla,
cherimoya, jaboticaba, etc., are of more recent introduction, and some
of these have not received the attention of the plant breeder to any
appreciable extent.
Through the centuries preceding recorded history and up to recent
times, progress in the improvement of most subtropical fruits was
accomplished by the trial-error method, which is crude and usually
expensive if measured by modem standards. With the general accept-
ance of the Mendclian principles of heredity — unit characters, domi-
nance, and segregation — early in the twentieth century a starting point
was provided for the development of a truly modern science of genetics.
In tins article it is the purpose to consider how subtropical citrus
fruit crops have been improved, are now being improved, or are likely
to be improved by scientific breeding. Each of the more important
crops will be considered more or less in detail. Before proceeding
to these considerations, however, it is desirable to define the province
of subtropical fruit culture and to take a glance at the economic im-
portance of the subtropical fruit industry.
The region where subtropical fruits are produced, as the name
indicates, is between the true Tropics, where frost never occurs, and
the temperate region, where normally the temperature often falls
below freezing and stays below for a considerable part of the winter
season. In this intermediate region the temperature occasionally
goes below freezing but not as a rule below 25° F., so that when neces-
sary the trees can be economically protected by artificial means.
Because of the influence of large bodies of water, the protection of
mountain ranges, or planting where the topography gives good air
drainage, this type of region may be extended as "islands" con-
siderably beyond the usual subtropical region.
The types of fruit crops grown merge into those of the true Tropics —
citrus, avocado, mango, etc. — and no hard and fast division can be
i Italic numbers in parentheses refer to Literature Cited, p. 808.
749
750 YEARBOOK, 1937
drawn on the basis of fruit types except that forms possessing resist-
ance to low temperature are of major importance in the subtropics.
Diverse types are cultivated, of which the familiar citrus fruits are
among the most outstanding, followed by the pineapple, fig, olive,
avocado, date, persimmon, mango, papaya, guava, pomegranate,
lychee, granadilla, cherimoya, loquat, jujube, and other minor types.
In the United States some of the crops, notably citrus and
avocado, have become staple dessert and salad fruits. Others,
notably the date and the fig, are used primarily as confections.
The olive is used in preserved form or for oil. Some of these
fruits were recognized as important sources of indispensable vitamins
even before the true function of these chemical regulators was
fully understood. limes, for instance, have long been included by
the British as a regular part of the diet of seamen as a preventive
of scurvy. During the recent Ethiopian campaign, the entire Italian
export crop of lemons was reserved for the army of invasion, and
it is reported that deficiency diseases were at a minimum. Besides
the citrus group, pineapples, papayas, dates, avocados, mangoes,
and other subtropical fruits are known to be unusually high in
vitamins.
Some of these fruits, for example the mango and the papaya, are
extensively cultivated but primarily for local consumption. Higgins
and Holt (80, p. 17) remark: "Excepting the banana, there is no fruit
grown in the Hawaiian Islands that means more to the people of this
Territory than the papaya, if measured in terms of the comfort and
enjoyment furnished the people." This applies to the papaya in
other tropical countries as well; to the avocado in Central America
and the West Indies; and to the mango in India, southeastern Asia,
Malaya, Puerto Eico, and the West Indies in general.
OUTSTANDING in the story of citrus fruit improvement was
the work of A. D. Shamel, of the United States Department of
Agriculture, and his coworkers, in studying bud mutations. In
the past 18 years, probably 10 million buds of superior strains
of the Washington Navel orange, the Valencia orange, the Marsh
grapefruit, the Eureka lemon, the Lisbon lemon, and miscellaneous
citrus varieties have been sold to California growers alone as a
result of this work. Two special strains produced fairly recently —
the Robertson Navel orange and the Dawn grapefruit — are now
being widely distributed and seem to have great promise. In
addition, the intensive study of bud mutations, backed by careful
statistics, was important in teaching growers to keep a close
watch for branches mutating toward poor types, so that they could
be eliminated from the orchard.
CITRUS FRUITS
751
The subtropical fruit production regions in the continental United
States are indicated in figure 1. The annual farm value (1934-35)
of the chief subtropical fruit crops grown in the United States for
Figure 1. — Citrus-produ/ciiig areas of ihe United States. Solid black denotes areas of
commercial production of sweet and tangerine oranges, grapefruit, or acid citrus fruits
(lemons or limes). Shading denotes areas producing satsuma oranges or minor quanti-
ties of other citrus fruits. The dolled boundary lines indicate the approximate
northern limi Is of the three subtropical crop regions: (I ) Son theaslern humid, (2) central
irrigated, and (3) southwestern irrigated.
which figures are available — citrus, fig, olive, avocado, and date —
amounts to approximately $140,000,000, distributed as follows:
Citrus fruits, $135,000,000; fig, $1,706,000; olive, $1,260,000; avocado,
$959,000; date, $390,000.
The distribution of the total return for citrus fruits in the United
States in 1934 is given in table 1.
Table ].. — Citrus production in the United States 1934
[From the United Slates Department of Agriculture, Agricultural Statistics, 1936]
Fruit
State
Total Price
production I per box
Total
value
Boxes
41, 565, 000
15, 500, 000
595, 000
170, 000
140, 000
203, 000
88,000
Dollars
1.80
1. 55
1.05
1. 50
1. 15
1.25
1.30
Dollars
74, 817, 000
21, 025, 000
624, 750
255, 000
161,000
366, 250
114,400
Florida ._ ..... . .. _
Texas.. . _. ...
Arizona. .. _.
Alabama. ... _ . . _ _. .
Louisiana ._
Total or average
58,351,000
1.72
100,303,400
Grapefruit
12, 500, 000
t, 788, 000
2, 720, 000
1,240,000
.91
1. 10
.85
.85
1 1, 375, 000
1,960,800
2, 312, 000
1,054,000
California-
Texas.. .. _.
California
Florida _
Total or average
18, 218, 000
.92
16,707,800
7, 500. 000
8,000
2.30
3. 50
17, 250, 000
28,000
Total
134, 349, 200
1 " i""~
752 YEARBOOK, 1937
EARLY HISTORY OF CITRUS FRUITS
The citrus fruits as a class are native to southeastern Asia — eastern
India, Indo-China, southern China, the Philippines — and here they
were first brought under cultivation. A monograph on the oranges
of Wenchow, Chekiang, Nan Yen-Chih's Chu Lu, composed in China
during the period 1174 to 1189, is the earliest treatise on citrus cul-
ture extant (26). Even at this early date three horticultural groups
of oranges were recognized and the total number of varieties listed
was 27.
Although there are a dozen or more types of citrus fruits, only five
or six are of major importance from a commercial standpoint. The
most important of these grown for fruits are the sweet orange, Citrus
sinensis (L.) Osbeck; the grapefruit, G. grandis (L.) Osbeck2; the acid
citrus fruits, including the lemon, C. limonia Osbeck, and the lime,
C. aurantijolia (Christm.) Swingle; and the mandarin orange group,
including the tangerine orange, C. nobilis var. deliciosa Swingle, and
the satsuma orange, C. nobilis var. unshiu Swingle. Other types
that are of importance mainly as rootstocks are the sour or Seville
orange, G. aurantium L. ; the rough lemon, G. limonia Osbeck; and
the trifoliate orange, Poncirus trtfoliata (L.) Raf. In some foreign
countries the sour orange, the pummelo (G. grandis),2 and the citron
(G. medica L.) are of relatively gi*eater commercial importance than
in the United States.
From the Orient the various types and varieties spread to other
parts of the world along the trade routes. The citron reached the
Mediterranean region at an early date, as it is mentioned by
Theophrastus. The sweet orange was apparently not introduced
into Europe until the early fifteenth century. The sour orange
reached Spain by way of northern Africa. The lemon and the lime
were apparently introduced into Europe about the same time as the
sweet orange, and several varieties are described by Ferrarius and
other writers. Lemon culture first became important in Sicily,
Corsica, Genoa, and other parts of southern Europe.
On his second voyage to the New World in 1493 Columbus stopped
off for 2 days early in October at Gomera, Grand Canary Island,
where he purchased livestock and fruit and vegetable seeds, among
which were "seeds of oranges, lemons, and citrons." He reached the
island of Hispaniola on November 22, 1493, and in the course of
establishing a colony he "set o\it orchards, planted gardens" (40).
The historical records of introduction to other parts of the Americas
have not been exhaustively searched, but citrus fruits were estab-
lished at St. Augustine, easteru Florida, by 1579 (12) and in Peru
before 1591 (82). They were introduced into southern California in
1 769 by Franciscan monks at San Diego (43), and there were undoubt-
edly many similar introductions into Brazil, Mexico, and other
regions settled by the Spanish. In Florida the sour orange, and to a
lesser extent the sweet orange and the lime, escaped to the wild.
It is now known, however, that the so-called "wild lime groves"
on the lower east coast keys of Florida were in fact planted out by
! Citrus grandis (L.) Osbeck, as here used, includes the type, the sour shaddock; and two varieties, (!)
the commonly known grapefruit and (2) the pummelo, used solely as a salad fruit as explained in the text.
The term pummelo should not ho confused with pomelo, sometimes used as a synonym for grapefruit.
CITRUS FRUITS 753
Henry Perrine, to whom in 1838 Congress had granted a tract of land
6 miles square on Biscayne Bay for the establishment of economic
tropical plants. Before his death in the Indian Key massacre of 1840
he had established a nursery of upward of 200 species and selected
varieties of useful tropical plants (58).
REGIONAL CHARACTERISTICS IN THE UNITED STATES
Commercial citrus growing in the United States presents striking
contrasts, due primarily to climatic conditions in the main centers of
production (fig. 1). In Florida at an early date the sweet orange, the
tangerine orange, and the grapefruit found a congenial home; in
California the sweet orange and the lemon have proved the basis for
profitable industries, with grapefruit secondary in importance.
Texas and Arizona have more recently come into the picture, especially
for grapefruit production.
Differences in varieties and seasons of maturity are likewise in sharp
contrast. In California two varieties of oranges, the Washington
Navel and the Valencia, furnish fruit maturing from November to
November, a year-round shipping season. In Florida three or four
sweet orange varieties, together with seedlings, are generally required
to give a shipping season from October to May. In California
lemons are more or less everbearing, affording a supply throughout the
year. The Florida and Texas grapefruit crops mature practically
during the same season (the fall and winter months), the California
and Arizona crops coining in somewhat later. Similar contrasts are
to be noted with the rootstocks used in these regions. These and
other regional contrasts will be discussed more in detail later.
Thus it will be seen that because of differences in climate and in
variety adaptation, citrus fruits, with their highly important vitamins,
are available to the American consumer throughout the entire year.
In general it may be said that grapefruit has been America's chief
contribution to citrus culture, its recognition in Florida as an appe-
tizing breakfast fruit gradually changing this curiosity of the citrus
family into a formidable rival of the sweet orange in the national
SOUTHEASTERN HUMID REGION
In the southeastern humid subtropical crops region, citrus develop-
ment began in eastern Florida in the vicinity of St. Augustine and along
the Indian River and in north-central Florida in the general vicinity
of Palatka and Ocala as far south as Lake Monroe. On the west
coast of Florida the development took place in the vicinity of Tampa
Bay and southward. The outstanding pioneers in the introduction of
citrus varieties during this period (1870-95) were E. H. Hart (fig. 2),
H. S. Sanford, and Lyman Phelps. By the 1880's the industry in
northeastern Florida was fairly important, but in the winter of 1894-
95 it was practically wiped out by two severe freezes, and the center of
the industry was moved farther south, to the central ridge section and
the southern coastal areas, where most of the citrus growing is now
located. Today the industry is based primarily on the sweet orange,
grapefruit, tangerine, and lime.
On the upper Gulf coast a citrus industry was established in the
Delta district south of New Orleans, based primarily on the sweet
754
YEARBOOK, 1937
orange. Satsuma growing along the St. Johns River and near Jack-
sonville began about 1900, spreading thence westward — because of the
cold resistance shown by this type during the 1894-95 and 1899
freezes — to the Gulf coast region in western Florida, Alabama,
Mississippi, Louisiana, and Texas.
The early plantings of sweet oranges made in various parts of
Florida consisted primarily of
groves established from seedlings,
and it was only later that the
practice of budding improved
varieties was gradually adopted
with the introduction of meri-
torious early, midseason, and late
sorts, beginning in the late 1870's.
Since the citrus tree is relatively
long-lived, the seedling groves,
producing fruit mostly midseason
in maturity, are still an important
factor hi Florida, and they pro-
duce approximately 30 to 40 per-
cent of the State's total midseason
sweet orange crop. However,
V budded varieties of recognized
merit have been used almost
entirely hi new plantings and re-
placements for the last 40 years.
Grapefruit first attained com-
mercial importance in the United
States. This was between 1880
and 1885, when the first grape-
fruit were sliipped from Florida
to the Philadelphia and New York
markets. In Florida the industry
received a set-back on account of
the freeze of 1894-95, but it
gradually expanded again, reach-
ing a peak by 1929.
The lemon and the lime, which were classed together in early times,
were introduced into the New World by the early Spanish explorers
and settlers. The everbearing and rough lemons were among the
early introductions into Florida, and the latter had escaped to the
wild by the time permanent settlements became common.
Prior to the great freeze of 1894-95 the lemon industry of Florida
was of considerable commercial importance. During the year pre-
vious to the freeze the annual shipments amounted to 140,000 boxes
of lemons. Up to the present the industry has not been rebuilt, but
recently attempts have been made to reestablish it. Limes are grown
in southern Florida, chiefly on the keys, in Dade county, and m the
south-central ridge section.
The mandarin oranges include the King, tangerine, and satsuma
types. The tangerine was introduced into Europe from the Orient
during the first half of the nineteenth century and was produced on
Figure 2— Edmund H. Hart (1839-98),
recognized as a skilled horticulturist and a
pioneer in Florida citrus culture. His
name is chiefly associated with the Hart's
Late or Tardiff orange, now called Valencia,
which he first brought to fruiting and
introduced into general use in Florida dur-
ing the 1870*s.
CITRUS FRUITS
755
a commercial scale in Italy as early as the 1840's. It was introduced
into Louisiana between 1840 and 1850 and later was brought to
Florida, where it is grown as a fancy fruit to a greater extent than in
California or Texas. Another member of this group, the satsuma, is
outstanding in being the most frost-hardy of all the larger fruited
citrus types. It is grown primarily in the upper Gulf coast region,
with the chief center of produc-
tion in western Florida and sou th-
em Alabama and Mississippi.
Southwestern Irrigated
Region
In the southwestern irrigated
subtropical crops region a citrus
industry has been established in
California, primarily in the sou th-
em coast and interior valley sec-
tions. In the southern coast
section the industry is based
almost entirely on sweet orange
and lemon, and in the interior
valley section on sweet orange
and grapefruit. An extension
into the irrigated section of
Arizona occurred later, founded
primarily on the grapefruit.
Citrus seeds were disseminated
from other parts of Mexico to
the peninsula of Baja (Lower)
California probably in the early
1700's, and later, in 1769, were
introduced to Alta (Upper) Cali-
fornia by Franciscan mission-
aries, who established a chain of missions for 400 miles along the coast.
According to Coit (11), the early settlers secured orange trees from the
missions, and a number of small plantings were found in private gar-
dens in the 1830's and 1840's in the vicinity of Los Angeles. These
early plantings stimulated further interest, and in 1857, trees were
planted at old San Bernardino and Highlands, in 1865 at Crofton,
and in 1 87 1 on land now occupied by the city of Riverside. T. A. Garey
(fig. 3), of Los Angeles, the outstanding nurseryman of that time, im-
ported large numbers of important varieties during the period 1868 to
1875. His introductions were apparently from Florida, Australia, and
southern Europe, as well as from Ellwanger & Barry, of Rochester, N.
Y., and Sir Thomas Rivers, of Sawbridgeworth, England. In the
southern and central parts of California the industry was only of local
importance until after the completion of the Southern Pacific Railroad
in 1876, when the first carload of fniit was shipped to St. Louis, Mo.,
arriving in good condition after a month in transit.
The grapefruit industry in the Southwest— California and Arizona-—
began after the introduction of the Marsh variety in 1890; the plant-
ings of other varieties previous to that time did not prove profitable.
Figure 3.— Thomas A. Garey (1830-1909),
pioneer California nurseryman, who made
extensive introductions of citrus varieties
during the period 1868-75.
756
) I ARBOOK, 193 7
Great success in lemon culture has been achieved in California,
particularly in the southern coastal region, which produces a large
proportion of high-priced summer fruit.
Central Irrigated Region
In the lower Rio Grande Valley of Texas, in the central irrigated
subtropical crops region, an industry has been established based
primarily on the grapefruit and to a lesser extent on the sweet orange.
As early as the middle of the
last century scattered plantings
of a few citrus trees coidd be
found along the Texas Gulf coast,
particularly from Victoria Coun-
ty southward to Brownsville on
the Rio Grande. Experience
had demonstrated by the begin-
ning of the twentieth century
that regular citrus crops could
not be expected in the region
above the lower Rio Grande Val-
ley, on account of damage from
low temperature (48). In the
lower Rio Grande Vallev- Cam-
eron, Hidalgo, and Willacy
Counties — the development of
the industry may be grouped
into three periods. (1) Up to
1899 citrus fruits were grown for
home use and no partictilar at-
tention was given to the subject
of rootstocks. Seedlings and
budded trees were planted.
During this period, in 1809, the
trifoliate orange was imported
from northern China by William
Saunders, of the United States
Department of Agriculture, and
it was used to some extent as a
rootstock. (2) The resistance to frost shown by trees budded on tri-
foliate stock during the severe freeze of 1899 led to the extensive use
of this stock during the following decade (87). Although the stock
was valuable from the standpoint of frost resistance and encouraged
the pioneer growers to make further attempts, it had the serious de-
fects of dwarfing the scion variety and of being itself subject to foot rot
and cotton root rot (77). (3) The observations of some of the out-
standing pioneers, Charles J. Volz, Harry Banker, J. R. Robertson, F.
E. Elliot, Max Melek, and A. P. Wright, beginning after 1900, made
possible the growing of citrus fruits in commercial quantities.
Charles J. Volz (fig. 4), from Indiana, settled near Mission in
Hidalgo County, Tex., in 1905. He began the planting of citrus in
1908 and clearly demonstrated the superiority of the sour-orange
rootstock under the lower Rio Grande Valley conditions. Harry
Figure I. — Charles J. Volz, pioneer Texas
atrial grower since 1908, who demonstrated
the value of sour-orange rootstock for citrus
in the lower Rio Grande Valley of Texas.
This demonstration proved to be a turning
point in the development of the citrus
industry in that section.
CITRUS FRUITS 757
Banker, from Oklahoma, who settled near Brownsville, in Cameron
County, secured similar results with, the sour-orange rootstock
beginning in 1910 (87). With the solution of the rootstock problem
the industry showed at first gradual and later rapid development.
The citrus shipments from this section, consisting mainly of grape-
fruit, had reached 13 carlots in 1921 and increased "to more than 5,000
carlo ts annually by 1931. Yields were cut down as a result of hurri-
cane damage in 1933 and damage due to low temperature in 1933-34
and 1934-35, but the crop of 1936-37 reached a total of over 15,000
carlots. Fortunately for this new industry, the seedless type of grape-
fruity (Marsh variety and its pink-fleshed mutations) has been most
heavily planted in Texas, and this has doubtless contributed to its
favorable reception in many markets.
HAWAII, PUERTO RICO, AND THE PHILIPPINES
The sweet orange was introduced into Hawaii in 1792, and manv
citrus varieties have been cultivated there for over 100 years (54).
The climate is well adapted to citrus culture, but for commercial pro-
duction the situation is complicated by the presence of the Mediter-
ranean fruit fly, which limits production to local needs.
While citrus fruits, especially the sweet orange, have been grown
in a semiwild condition in Puerto Rico for perhaps 3 centuries,
commercial planting did not begin until about 1900. The first plant-
ings were largely of Florida orange varieties, but these were soon
largely discarded in favor of grapefruit (29). The varieties most
commonly grown are the Duncan and the Marsh. For budding stocks,
rough lemon, sour orange, and seedling grapefruit have all been suc-
cessfully used, the rough lemon being favored for rapid growth and
early production and especially for the lighter grades of soil. Wind
damage has caused frequent losses of trees and fruit and has directed
attention to the use of such plants as bamboos and casuarinas for
windbreaks.
Owing to the fact that the trees bloom intermittently, Puerto Rico
is enabled to ship grapefruit over a long season, a summer crop often
maturing from a previous fall bloom. Production for several years
past has averaged about a million boxes, of which approximately 25
percent is marketed as canned grapefruit. Puerto Rico is credited
with having initiated the canning of grapefruit "hearts", a product
that has grown rapidly in favor and has made grapefruit available
at all seasons and in many localities where fresh fruit seldom is
offered. Orange shipments from Puerto Rico, amounting to a half
million boxes in good seasons, consist largely of so-called "wild
oranges", which come in a considerable measure from seedling trees
cultivated as shade trees on coffee plantations.
In the Philippines citrus fruits have been grown for centuries,
forms of Citrus hyutrix DC. (kalpi), G. mitis Blanco (calamondin),
and G. grandis (pummelo) being native to the islands. It is only in
recent decades, however, that attention has been given to growing
the fruit commercially. Wester (88), beginning about 1910, brought
together an extensive collection of citrus varieties at Lamao, few of
which proved adapted to Philippine conditions. The mandarin
oranges as a class have proved best suited to commercial culture,
758 YEARBOOK, 1937
and a local variety known as Batangas mandarin is being grown on a
considerable scale chiefly for the Manila market. The Batangas,
the King, and the Szinkom mandarins, several pummelo varieties —
including the Siamese — and the Valencia orange constitute most of
the recent plantings. Genetic studies and hybridization work have
been inaugurated by Torres, and one hybrid variety, Szinbat (Szinkom
X Batangas), has been introduced. It is characterized as productive,
of good quality, and resistant to wind injury. Further breeding and
selection work is in progress, special studies being made of poljrem-
biyony — to be discussed later — in scion and stock varieties.
BREEDING MATERIALS
The citrus breeder is concerned with two kinds of plant materials
within the Rutaceae — the citrus group proper, containing the types
closely related to the widely known sweet orange, and various species
in genera somewhat less closely related. The first or citrus group
contains all of the valuable types cultivated for their fruits or used
as rootstocks, and the second is of value in some instances as stocks,
as breeding material, and in furnishing a clue to the evolutionary
development of the branch of the Rutaceae to which the citrus fruits
belong.
The citrus group proper is characterized by great diversity in
morphological characters, and this has led some systematic botanists
to the multiplication of species. The classification of Swingle (68),
however, is conservative, has been widely accepted, and is used, in this
report. The only exception made is in the case of Citrus grandis,
where it has been necessary to recognize two varieties besides the
type species.3 The horticultural differences in a number of cases are
so great, as will be pointed out in the discussion of dessert quality
later, that the single type designation is quite inadequate.
The followiug types commonly grown for their fruits or as root-
stocks are in the three genera Citrus, Fortunella, and Poncirus:
Sweet orange, Citrus sinensis (I/.) Osbeck.
Sour orange, C. aurantium L.
King orange, C. nobilis Lour.
Tangerine orange, C. nobilis var. delirium (Tcnorc) Swingle.
Satsuma orange, C. nobilis var. unshiu (Mak.) Swingle.
Shaddock, C. grandis (L.) Osbeck.
Grapefruit, C. grandis.
Pummelo, C. grandis.
Citron, C. medica L.
Lemon, C. limouia Osbeck.
Lime, V. awantifolia (Christm.) Swingle.
C. ichangensis Swingle.
Kalpi, C. hystrix DO.
Calamondin, C. mitis Blanco.
Kumquat, Fortunella spp.
Trifoliate orange, Poncirus trifoliate, (L.) Kaf.
The citrus breeder is fortunate in possessing material that presents
so many diversities — in dessert and keeping quality, season of ma-
turity, resistance to disease, and regional adaptation. All of these
will be developed in detail in the following text, but the dessert quality
of the types will be discussed at this point.
Seefootiiole2, i>. 752.
CITRUS FRUITS 759
Character and Uses of the Fruits
Some of the fruits listed above — sweet orange, grapefruit, lemon, and
lime — have become well known to northern readers and need to be
only briefly differentiated; a few, however, are little known and will
require more detailed descriptions. In general it may be stated that
the taste qualities of mature citrus pulp and juice are dependent on
various combinations of sugars, acids, glucosides, esters, and peel oil.
The first two, the sugars and acids, are the basic matrix and give
variations from sour through tart, sweet, and insipid, and the latter
contribute bitter and aromatic principles. The bitter principle, fur-
nished by glucosides, is apparent only if it is in solution in sufficient
amount in the juice (5, 78, 79). This is normally not the case except
in such types as grapefruit and lime. The aromatic quality contributed
by peel oil is important in some cases.
In most commercial varieties of sweet orange the sensation of sweet-
ness predominates, combined with a slightly perceptible tartness. In
most varieties the quality contributed by esters is slight, but in such
varieties as Pineapple the suggestive "pineapple" ester is outstanding.
In the mandarin orange or free-peeling group, the tangerine oranges
are characterized by the pleasant "tang", which is due to esters. The
King and satsuma oranges in this same group have taste qualities
similar to those of the sweet orange.
In grapefruit the bitterness of the glucoside naringin gives the
sprightly taste added to the mild acidity that makes the fruit out-
standing as a breakfast appetizer.
The pummelo, as distinguished from the sour shaddock, is used
only as a salad fruit. The largo juice sacs are separated from the
locular wall tissues and are served like any other salad. The flavor in
the better varieties is due to a very slight acidity and the presence of
only a very little glucoside, but it is predominantly sweet, and in-
imitable quality is contributed by esters.
In lemon and lime, acidity is of first importance. A good acid
citrus fruit, as pointed out by Traub and Robinson (80), should have
from 6 to 7 percent of acid. In lime the characteristic glucoside, which
has not been studied in detail, lends the "lime" taste. The peel oil of
lemon and lime also gives desirable qualities.
The citron is used entirely as a preserve. The kumquat is used both
in preserving and in table decorations. It is also eaten entire, out of
baud. Two general types are recognized, sweet and sour, in both of
which the rind has little of the pungent oil common to most citrus
fruits.
In the case of hybrids, intermediates have in some instances been
secured, especially in the tangelo oranges — hybrids between the grape-
fruit and the tangerine orange. In these hybrids, as a rule, the esters
are predominant in distinguishing the flavor of the new fruits from the
common sweet orange. In the Perrine lemon, a hybrid between the
lemon and the lime, there is a mild suggestion of the lime glucoside.
When hybrids between citrus species first appeared it was custom-
ary to apply various compound names, such as tangelo, tangor,
oranguma, limelo, lomelo, etc., to indicate the parentage. It was
soon realized that this would lead to confusion from the horticultural
760 YEARBOOK, 1937
viewpoint, since some crosses gave rise to more than one horticultural
or market type. The grapefruit-tangerine cross (tangelo), for in-
stance, gave rise to forms like the now generally known tangelo orange,
and also varieties that resemble the grapefruit in structure and juice
quality but with the rind, flesh, and seed color of the tangerine. A
strict application of the term "tangelo" would have included both of
these forms. The difficulty was overcome by the decision to place
hybrids for purposes of horticultural classification with the well-known
types that they most resemble, and to use the interspecies compound
designations only in their scientific application. On this basis most
of the tangelos already introduced, being more like the sweet orange
in structure and use, were designated as a group of the sweet orange,
possessing relatively high quality with special reference to a pleasing
blending of esters, sugars, and acids. Such a class would naturally
contain also such hybrids as the Umatilla (oranguma), a cross between
the sweet orange and satsuma orange, but very similar to the other
tangelo oranges, and also the Temple, apparently a naturally occurring
hybrid between the tangerine and a grapefruit variety similar to the
Tresca.
Representatives from a great number of related geneia, Glycomis,
Claucena, Chalcas, Feronia, Feroniella, Aeglopsis, Aegle, Swinglea
(Chaetosperrrmm), Balsamocitrus, Lavanga, Ilesperethusa, Triphasia,
Severinia, Citropsis, Atlantia, Eremocitrus, and Microcitrus, have been
introduced by the United States Department of Agriculture during
the last 25 years. These are listed in table 6 in the appendix. Some
of these may prove of value in citrus breeding and as rootstocks.
Although certain species have entered to some extent into hybridiza-
tion work, no hybrids of immediate value have been secured up to
the present. The material, however, is valuable to the breeder from
another standpoint, for it presents an opportunity for an evolution-
ary approach to the study of relationships within the group.
GENERAL TRENDS AND PROBLEMS
The early history of citrus improvement in the United States is con-
cerned almost entirely with the introduction of varieties from other
citrus-producing regions, mainly through private initiative. This
period extended to the 1870's in this country. Toward the end of the
nineteenth century, hi the United States, the immber of varieties was
increased by the addition of those originating as chance seedlings and
possibly by bud mutations accidontly propagated. Still later, im-
proved types appeared as the result of artificial cross-pollination.
Breeding work was undertaken by the Department of Agriculture in
1892, and the the State agricultural experiment stations in California
in 1910, in Florida in 1924, in Alabama in 1933, and in Texas in 1934.
Problems Peculiar to Citrus Breeding
The breeding of citrus fruits presents two problems not met with
in the case of the usual annual crops such as grains, which can be
grown in great numbers on a relatively small area at small expense.
First, as a rule it takes from 6 to 10 years to fruit a seedling citrus
tree unless the variety is top-worked on an older tree, in which case
the time will be cut in half. The trees are expensive to produce and to
CITRUS FRUITS
761
test out in orchard formation on various soil types and under various cli-
matic conditions. It is necessary, therefore, to plan breeding experi-
ments so tha t only progeny are grown th at promise varieties of immediate
value or additions to the knowledge of citrus genetics. With such
a handicap, the work
has not progressed at
a very rapid rate.
Theotherdifhcultyis
duetothephenomenon
of polyembryony —
inclining "several em-
bryos per seed" (fig. 5)
In the case of plants
reproducing by seeds,
each single seed as a
rule gives rise to one
seedling, which is the
result of the union of
the male gamete (re-
productive cell), con-
tributed by the pollen
grain, and the female
gamete (egg cell), con-
tained in the ovary of
the flower. In each
of these gametes the
number of chromo-
somes has been nor-
mally reduced by half
preparatory to repro-
duction (the haploid
number of chromo-
somes), and the union
of the two results in a
complete complement
of chromosomes, called
the diploid number,
which is characteristic
of all of the body cells
of the individual plant
as distinguished from
the sex cells. In the
case of the citrus seeds,
however, a normal em-
Fifftre .5. — Nucellar enihryony in citrus, showing four
seedlings sprouting from single seeds (McCarty grape-
fruit): A, One vigorous seedling and three relatively less
vigorous; B, four vigorous seedlings; C, similar to A after
separation. (See also fig. 17, showing cytological details.)
bryo produced by the
union of the male and female gametes may be present, and in addi-
tion one or more — sometimes as high as 15 — additional embryos
that have arisen from projections into the embryo sac of the sur-
rounding maternal tissue (nucellar tissue). When these projections
develop into embryos they have the full chromosome complement
(diploid) of the mother plant without the union of two gametes.
Citrus types and varieties may vary greatly in the number of nucellar
laSBOl"— 37-
-40++
762 YEAR HO OK, 193 7
embryos produced. Seedlings that develop from ruicellar embryos are
called apogamic seedlings (literally, "without marriage").
Unless the parents have unlike vegetative characters, it is not pos-
sible to distinguish the sexually produced or hybrid embryo from
those that arise by nucellar budding, though in the latter, of course,
only the characters of the female parent will appear. This means
that a great many more seedlings must be grown to the point where
they can be distinguished than in the case of crops producing only
normal or seminal seedlings. Citrus breeding, therefore, will con-
tinue to be even more costly than ordinary tree-fruit breeding unless
a method can be worked out to achieve practical control of nucellar
embryony.
Tims it is natural to expect relatively slow progress. The results
from cross-pollination followed by inbreeding and selection, and from
back-crossing on the parent types, will not be available in a few sea-
sons but only after a considerable period of time. However, the
earlier pioneers in this field have laid the foundation, and in the future
it is probable that the rate of progress can be considerably accelerated.
Methods of Breeding
Fortunately no problem is presented with reference to controlling
pollination in citrus. The flowers are relatively large and the ordinary
bagging technique with brown-paper bags has proved sufficient. In
practice the flowers are emasculated before pollen is shed and then
bagged. They arc pollinated soon after opening, and the bags, which
were removed for pollination, are replaced and left on until the petals
have fallen and the fruit begins to grow. To protect from loss by
dropping, the fruits are usually covered with cheesecloth bags.
Pollen is gathered from flowers that have been bagged when still
closed and is used immediately unless flowering of the parents desired
does not overlap, in which case the pollen is stored for later use.
Kellerman (85) has shown that citrus pollen dried over concentrated
sulphuric acid and sealed in glass vacuum tubes at about 0.5 mm
pressure can be kept in. a viable condition for more than 2 months.
When the seeds are removed from the harvested mature fruits
secured as a result of artificial pollination, they are thoroughly washed
and are planted at once in flats, for the germination percentage usually
decreases if they are allowed to dry in the air. The flats containing
the seeds arc placed in a coldframe to prevent damage by heavy rains.
When seedlings are 6 to 18 months old they are planted in nursery
rows, usually 12 by 6 feet apart, and given good culture. As soon as
the fruiting stage is reached, usually in 5 years, or sooner if top-
worked on old trees, detailed records are taken of tree and fruit char-
acters, and all seedlings that show no immediate promise or appear
to be of no value for future breeding are destroyed. These records
determine the apparent worth, if any, of the plants as varieties for
cultivation, and also serve as a basis for working out genetic principles.
The seedlings are tested for vigor, including disease resistance,
bearing capacity, and regional and rootstock adaptation. The fruits
are tested for size, shape, juice percentage, season of maturity, num-
ber of locules and seeds, rind thickness, percentage, of "rag", percent-
age of sugars and acids, effective acidity (pH) of the juice, and the
CITRUS FRUITS 763
flavor of the juice. Out of a groat number of seedling individuals
only a very few are finally selected for introduction, and these are
released only after favorable performance in preliminary fruiting
tests in a number of locations.
Objectives of the Breeder
The first consideration in citrus breeding is excellent dessert quality.
What constitutes high quality has been previously discussed, and we
pass to the consideration of tree and other fruit characters that the
breeder has in mind when making his crosses and selections.
The tree (scion variety) should be compact in habit, but a vigorous
grower and a prolific bearer. It should be resistant to the common
citrus diseases and to low temperatures, and congenial with the root-
stock or rootstocks used in the region. The fruit should mature at
the proper season or seasons to suit market needs. There are also
other characters of importance, such as thomlessness.
The fruit should have excellent dessert quality and contain few or
no seeds; the shape and size should be suited to commercial require-
ments and to ease in packing; shipping or keeping quality, including
resistance to storage diseases, should be good; the exterior, including
texture and color of rind, should be attractive; and, in particular,
the vitamin C content should be up to the standard. With the rapid
growth of a new industry in canning "hearts" and juice of both grape-
fruit and orange, special attention may need to be given to the require-
ments of this promising industry. For instance, it has already become
evident that the pulp of Marsh grapefruit lacks the firmness necessary
in a good canning grapefruit. With the growing tendency to utilize
citrus fruits in juice form and in mixed drinks, the high color of the
juice characteristic of the tangelo group of hybrids is proving a
decided advantage.
The tree used as a rootstock should be adapted to the soil and
climatic conditions, be free from or resistant to trunk and root diseases,
and produce a high percentage of nu cellar embryos, and it should not
be so vigorous in growth as to make the fruit of the scion coarse, of poor
texture, and comparatively low in total solids (sugars and acids) and
therefore insipid in taste (6, 80).
As the margin between production costs and sales returns becomes
narrowed with increasing supplies of citrus fruits, any adaptation that
might lessen the cost of production becomes vitally important. This
places emphasis on disease resistance in any breeding program, to
reduce both expense for grove sanitation and losses due to infected
trees and fruit. In citrus the list of such diseases is quite extensive
and varies with citrus types and varieties.
The task of breeding for resistance to injury from insect and other
animal pests on plants presents the major difficulty of developing a
practical technique.
In Florida the chief citru s diseases are melanose, affecting tender twigs,
leaves, and immature fruits, and stem-end rot, affecting mature fruit,
both caused by Diaporthe (Phomopsis) citri (Fawc.) Wolf; sour orange
scab (Elsinoe fawcetti Bitancourt and Jenkins), affecting leaves and
fruits; key lime anthracnose (Gloeosporium limetticolum Clausen) ; foot
rot {Phytophthora parasitica Dastur) ; and psorosis, cause undetermined.
761 YEARBOOK, 1937
In the Southwest, brown rot. gummosis and foot rot (Phytophthora
citrophthora (Sm. and Sin.) Leonian and P. iwrasiticq) ; psorosis; and
shell bark {Diaporthe citri) are of major importance; and in the lower
Rio Grande Valley gummosis, scaly bark, and stem-end rot (melanose).
Achievements \;vi) Futuke Possibilities
In spite of the peculiar difficulties encountered in citrus breed-
ing, definite achievements can be recorded, and the outlook for the
future is most encouraging. The work in the past has shown that
worthwhile results may be secured from appropriate crosses and
that important strains and varieties may arise by bud mutation. In
addition a beginning has been made in laying a foundation of genetic
principles.
The work in citrus hybridization carried on by the Department of
Agriculture workers since 1S93 has shown that the combinations
of grapefruit and tangerine and of lemon and lime give the most
promising results. The first have given rise to high-quality fruits
known as the tangelo oranges, and the latter to a high-quality lemon,
the Perrine. The work of Frost, of the California Agricultural Exper-
iment Station at Riverside, has shown that crosses within the mandarin
orange group give worth-while results.
Apogamic seedlings from crosses have also given rise to important
varieties in grapefruit and in sweet, sour, and satsuma oranges.
Bud selection has given superior strains of known varieties and has
served to stabilize standard varieties. Crosses with more distantly
related relatives of citrus, Citrvs X Poncirus, citrange X ForHnella,
citrange X calamondin, etc., have proved interesting from the genetic
standpoint and have also given some concrete types of possible value
in horticulture- citrange, citrangequat, and citrangedin. Reference
to particular hybrids in which definite objectives have been attained
are found in the text and in table 6.
Thus the. ground work has been laid by the earlier workers. With
the wealth of breeding material and the increase of interest in this
field, research in citrus breeding may be expected to show greater
progress in the years to come.
Some idea of what the future holds in store as a result of citrus
breeding can best be gained from the following quotations contained
in the report made by II. B. Frost, actively engaged in citrus breeding
at the Citrus Experiment Station, Riverside, Calif., in connection
with the cooperative survey of plant and animal breeding:
If we wish to produce a variety or strain that is very similar to a standard
variety, such as the Valencia, but superior in some important feature, such as
eating quality, generative seedlings from either selfing or narrow crossing are very
unpromising, for two reasons: (I) they are usually weak and very unproductive,
and (2) they are usually very unlike the parent or parents. The best chance of
success, although a very uncertain one, seems to lie in the discovery of superior
bud-variation forms. Such forms may be found, of course, either as "limb
sports" or as whole trees which have happened to be budded from variant
branches. They may also be found as seedlings derived from nucellar embryos
that happen to be formed on a variant branch; in this case the seedlings are likelv
to be indistinguishable from other nucellar seedlings until they produce fruit.
On the basis of the time and expense required, the search for bud variations in
commercial orchards seems more promising than the growing of seedlings. A
good new bud-variation type may in some cases, however, be variable because of
CITRUS FRUITS 765
mixture with the parent variety in the same shoots to form a chimera, and the
growing of seedlings may then be the best method of getting the new type sepa-
rated from the parent variety. Variability may in some eases be inherent in the
constitution of a new form, however, so that it will never become stable.
X-ray treatment probably can be used, as it has been with other plants, to
increase greatly the frequency of new genetic variations. It seems most likely
to be useful by producing variations in nucellar seedlings.
For the production of new varieties of superior quality but with flavors very
unlike those of the present varieties, the great variability of hybrids offers much
promise, since we can use wide crosses, which commonly give vigorous hybrids.
Various hybrids of the tangelo and tangor groups, which are hybrids of mandarins
with grapefruit and with sweet orange, that have been introduced by the United
States Department of Agriculture, offer unique and very pleasant flavors. It is
now probable, however, that the best opportunities for securing superlative
quality are to be found in crossing within the mandarin species or group of species,
and therefore, it is very fortunate that certain crosses between mandarin-group
varieties produce vigorous hybrids.
It is advisable to make some further trial of the production of triploid hybrids
by pollinating tetraploids by diploids of other species (or of other sections of the
mandarin "species"). The only tetraploid form which at present seems to have
uracil promise for such use is the tetraploid Lisbon lemon, which combines good
seed production, comparatively low chromosome irregularity, and high propor-
tion of generative progeny.
The evidence on which these suggestions are based has only partly been secured
at the Citrus Experiment Station, and that on the results of selfing has very
largely been obtained in Dr. H. J. Webber's root stock experiments. The nature
of the work has ranged from chromosome counts and systematic records of various
tree and fruit characters, to the determination of the agreeableness of fruit flavors.
Any extensive gene analysis is clearly impracticable in citrus, yet certain evidence
has been obtained which seems to have definite significance" for general genetic
theory, when interpreted on the basis of gene analysis made on more favorable
organisms.
The problems that most concern the citrus breeder have been
listed by Frost as the determination of —
(1) The generality of the reduction of vigor with selfing and narrow crossing.
(2) The extent to which the proportion of nucellar seedlings can be predicted
from counts of total embryos. (3) (o) The extent to which triploids are unpro-
ductive of fruit, as compared with diploids of the same ancestry. (6) The extent
to which triploids can be produced by crossing diploids with tetraploids. (c) The
frequency with which triploids occur from crosses between diploids. (4) The
extent to which the prospects of high vigor, productiveness, good flavor, and other
horticulturally desirable characters in crossing can be inferred from knowledge of
the species or smaller taxonomic group to which a variety belongs, on the basis of
trial of other varieties of the same group. (5) The frequency with which new
genetic types arise by bud variation, and the extent to which this process can be
speeded up by X-ray treatment of seeds, pollen, etc. (6) The best methods of
modifying physiological conditions to secure high seed production in crossing, and,
if possible, high proportions of generative embryos.
With the present facilities, problems named under 1 to 4 above
may be solved partially, and to a much smaller extent those under
5 and 6 in the list.
IMPROVEMENT OF CITRUS VARIETIES
The improvement of citms varieties will now be briefly discussed
on the basis of citrus types — sweet orange, mandarin oranges, grape-
fruit, acid citrus fruits, and minor citrus fruits. In each case the
varieties will be considered by regions. Following this, citrus bud
selection and citrus root-stocks will be considered under separate
headings.
766 YEARBOOK, 1937
Sweet Orange Improvement
Florida
In Florida the bulk of the citrus crop is produced between October
and June. Good early-maturing and very late-maturing varieties
are of most importance from the breeding standpoint. The sweet
orange varieties of Florida have been described by Hume {32).
EARLY VARIETIES
Early-maturing sweet orange varieties for Florida are relatively
scarce, and it is desirable to give this fact due weight in any citrus-
breeding project.
The Hamlin is one of the early varieties usually recommended. It
was discovered in a grove planted in 1879 near Glen wood, which later
came into possession of H. E. Hamlin. Under the best cultural con-
ditions the acidity and sweetness are well blended, giving it excellent
flavor; the rind is smooth and glossy ; seeds are none too few ; the season
is October and November and later. Recent reports indicate that it is
sensitive to overfeeding and other unfavorable growing conditions,
which may lead to fruit splitting, riciness of pulp, and poor juice
quality.
The Parson Brown variety was introduced by C. L. Carnev, of Lake
Weir, about 1878, having originated at Webster in a seedling grove
owned by Parson Brown. Acidity and sweetness are fairly well
blended if the fruit is picked early; seeds, 10 to 19; season, October
and November.
Early sweet oranges usually have poor rind and flesh color when
harvested at the beginning of the season. This is a deficiency that
might be remedied by breeding methods.
The results thus far look promising. A hybrid, the Orlando tangelo
orange (fig. 6), introduced by the Department in 1931 and resulting
from a cross of the Bowen grapefruit pollinated by Dancy tangerine,
is early in maturity and can be harvested over a long season. The
variety is highly resistant to citrus scab. When first harvested in
late September or early October the rind color after degreening with
ethylene is a beautiful light yellow, but later in the season it takes on
a natural deep reddish-orange color. It is medium in size, and the
flesh color is deep orange. Its main defect is its seediness. Such a
defect can apparently be overcome in future breeding work, as will be
pointed out later.
MIDSEASON VARIETIES
A large number of midseason varieties were named and introduced
beginning in the 1870's. Among these the outstanding ones are the
Homosassa and Pineapple. The Homosassa is a variety of excellent
quality, with a sprightly, rich, vinous flavor; seeds, 20 to 24; season,
December to February. The Pineapple is the outstanding midseason
variety, having a glossy rind of deep orange color, vinous and sprightly
in flavor; seeds rather large and numerous. It originated near Citra,
Marion County, and received its name from the fine aroma reminis-
cent of the pineapple. It is today the most important midseason
sweet orange in Florida.
CITRUS FRUITS
767
The navel type of sweet orange is not suited to the Florida climate.
Although a number of varieties have been introduced, they have not
proved successful as the Washington Navel has in California.
Two midseason tangelo oranges, of the same parentage as the Or-
lando variety, introduced by the Department in 1931— Minneola
(December-January) and Seminole (February-April) — are outstand-
Figure 0. — Typical fruits of Orlando langelo orange (originally introduced as the
Lake variety), a hybrid between grapefruit (?) and tangerine (cf); remarkable for
earliness, maturing in October and November; highly resistant to scab. Introduced
by the United States Department of Agriculture.
ing from the standpoint of dessert quality, the Minneola especially
having the most delicate blending of esters, sugars, and acids. These
fruits have deep tangerine rind and flesh color, and their shipping
quality is good. Like the Orlando tangelo orange, the Seminole
(fig. 7) is highly resistant to citrus scab, the Minneola partially resis-
tant. The fruits are somewhat seedy.
LATE VARIETIES
The sweet orange industry up to the 1870's was based on seedlings
and clones producing early and midseason fruits. An event of great
importance took place when, early in the lS70's, the late type of sweet
orange, now called Valencia (fig. 8), was introduced into Florida by
S. P. Parsons, a nurseryman of Long Island, N. Y., and Palatka, Fla.
Parsons had secured it from Thomas Rivers in England, who had im-
ported it from the Azores and had cataloged it under the name "Ex-
celsior." Pnrsons gave trees to E. H. Hart (fig. 2), of Federal Point,
768
YEARBOOK, 1937
Figure 7. — Typical fruits of Seminole tangelo orange, a hybrid between
grapefruit ( 9 ) and tangerine (cf); midscason to late in maturity; replacing
the older Sampson variety because of its high color and flavor, resistance
to scab, and good shipping quality. Introduced by the United States
Department of Agriculture. (Natural size.)
CITRUS FRUITS
769
Figure 8. — Valencia orange, typical of the variety as grown on sour orange
rootstock in Orange County, Fla. It is characterized by late maturity (March to
June in Florida), firm flesh and rind, and fairly high content of citric acid,
contributing to its good holding and shipping quality. It is commercially
seedless, having normally two to five seeds.
770 YEARBOOK, 1937
Fla. Having lost the label, Hart distributed the trees under the name
of Hart's Late or Hart's Tardiff. The variety was exhibited before
the Florida Fruit Growers Association on April 25, 1877. The out-
standing characteristic of this variety is its late maturity. Its seasou
extends from March to June.
The variety was also imported into California, in a lot of citrus
varieties from Thomas Rivers, by A. Chapman, of San Gabriel, Calif.,
between 1870 and 1872. One of these varieties, labeled as a navel,
turned out to be a late-ripening nonnavel variety that fruited after
the other varieties were off the market. The variety was named
Valencia at the suggestion of a Spanish laborer, and Chapman sold it
under the name of Valencia Late. Nurserymen in California had
purchased stocks of Hart's tardiff, and a great many trees had been set
out. By the time it was discovered that the Valencia and Hart's
Tardiff were identical, the variety had attained commercial import-
ance in California, and the name Valencia was retained.
A variety similar to the Valencia, named Lue Gim Gong, for the
originator, "and introduced in 1912 by the Glen St. Mary Nurseries,
is described as very late in maturity. It is now generally regarded
as a strain of Valencia, from which it originated as a seedling.
The production of a tangelo orange (Umatilla), which resulted from
the pollination of the satsuma by the Ruby sweet orange and was
introduced by the Department in 1931, indicates what may be accom-
plished by breeding methods in the creation of late-maturing varieties.
In contrast with the parents — satsuma, early maturing, and Ruby, sweet
midseason — the hybrid matures its fruit in late February, March, and
April. The variety is highly resistant to citrus scab; the fruits are
medium to large in size; the rind and pulp color is deep orange, and
the quality is excellent. Seed content is variable.
To sum up: At the present time the sweet orange industry in
Florida is based primarily on two earlj- varieties, Hamlin and Parson
Brown ; on midseason seedlings and two midseason varieties, Pineapple
and Homosassa; and on one late variety, Valencia.
California
In California one early and midseason navel and one late nonnavel
variety have proved sufficient to produce an orange crop every month
in the year.
Contrary to popular opinion, the navel type of sweet orange is not
a modern product. It was described and pictured by John Baptisti
Ferrarius in 1646 and is apparently of early origin. As early as 1820
the Bahia form of the navel orange had made its appearance in
Brazil, where orange trees had been introduced by the Portuguese
settlers. Its excellent qualities were soon recognized, and the variety
was extensively propagated in the vicinity of Bahia. Even at this
early date the variety seems to have been subject to bud mutation,
and inferior types appeared that were unintentionally propagated and
introduced in South Africa and Australia. Those that reached
Australia also included desirable types.
The Bahia type of navel orange was first introduced into Florida
in the 1830's, but the trees were killed during the freeze of 1835. A
shy-bearing form of Bahia navel was introduced into California in the
CITRUS FRUITS
n
early 1870's. The strain was secured from S. B. Parsons, Flushing,
N. Y., who had received it from Thomas Rivers in England. In the
early 1870's an inferior type of navel orange was imported from
Australia into California, which set the precedent for referring to
inferior strains as the Australian navels to distinguish them from the
superior Bahia strain.
The story of the Washington Navel orange is a dramatic illustration
of the value of superior varieties of economic plants. In 1870 the
citrus industry had begun in Cali-
fornia, but there was no outstand-
ing early and midseason variety
of sweet orange generally adapted
to the climate. The early mission
seedlings and varieties intro-
duced after the middle of the
nineteenth century were being
tested out by various growers,
but there was a lack of standard-
ization in quality. The value of
alertness hi using the plant ma-
terial that has been produced as
a result of centuries of selection
is nowhere better illustrated than
by the timely action of the late
William Saunders (fig. 9), then
superintendent of gardens and
grounds of the United States
Department of Agriculture,
Washington, D. C.
In 1870, through the kind as-
sistance of a missionary stationed
at Bahia, Saunders imported
from Brazil 12 navel orange trees
in tubs. These were housed in
the Department greenhouse at
Washington, and propagations
were made for distribution to
the regions adapted to citrus
culture. The first propagations
Florida
Figure 9.—W illiam Saunders (1822-1900).
superintendent of gardens and grounds of
the United States Department of Agricul-
ture at Washington, D. C, through whose
efforts the Bahia navel orange was suc-
cessfully introduced from Brazil in 1870.
Three years later trees propagated by
Saunders were planted in California and,
under the name of Washington Navel, be-
came the basis of an epoch-making industry.
were sent largely to
and California, but at least one of this lot is still maintained by the
Department at Washington. Mr. and Mrs. Luther C. Tibbets were
attracted to the settlement at Riverside, Calif., and early in 1873,
before starting her journey, Mrs. Tibbets visited the Government
propagation gardens at Washington, where Mr. Saunders gave her
two Bahia navel trees. These were carried to California and planted
beside the Tibbets' cottage in Riverside (fig. 10). In February 1879
the fruit was awarded first prize over other navels exhibited from
Orange County, and these two trees were used as the source of ex-
tensive plantings. The variety was referred to as the Washington
Navel to distinguish it from the Australian importations. An attempt
was made to change the name to Riverside Navel, but this proved
772 YEARBOOK, 1937
unsuccessful. The great superiority of the Washington Navel (fig. 11)
was soon recognized, since it apparently was ideally adapted to the
climatic and soil conditions of California and produced a fruit of high
quality with the highest market appeal. The best strain of Wash-
ington Navel, according to Shamel and associates (61), is character-
ized by an —
open and somewhat drooping habit of growth and dense foliage with large, oval,
dark-green leaves. * * * Under normal conditions no pollen is produced by
the anthers of the flowers. * * * The fruits * * * are obovoid in shape
and generally of medium to large size. The rind is of medium thickness, and the
texture is smooth and grained. The color of the fruit is bright orange; the rag is
tender and comparatively small in quantity; the juice is abundant and of superior
quality, having a pleasing and sprightly subacid flavor. The fruits are seedless,
and the navel usually is small, sometimes rudimentary, with no development
except in the rind.
By 1885 enterprising nurserymen had introduced most of the
important varieties of the world, which were tested in comparison
with the local seedlings of special merit. Less profitable varieties
were rapidly eliminated, and by 1900 the area planted to the Wash-
ington Navel was larger than that of all other varieties in the State.
It is now generally recognized that one of the outstanding events in
the economic and social development of California was the introduc-
tion of this orange in 1873. During the period of more than 60 years
following, a great industry has been built up from the two small trees
planted by Mrs. Eliza Tibbets.
The Valencia variety of sweet orange, introduced into California
and Florida between 1870 and 1872 as already detailed, is the other
outstanding orange variety in the State. These two varieties are
grown almost to the exclusion of others. Climatic conditions vary
widely because of differences in rainfall, protection by mountain
ranges, the moderating influence of the ocean, and other factors.
These affect the ripening period of fruit varieties so that the same
variety matures at different times in various regions. When this is
coupled with "tree storage" in the case of the Valencia, which holds
its fruit in good condition for several months, the combination results
in a marketable fruit crop throughout the year. This tree storage is
made possible by the dry summer climate with comparative freedom
from fruit-destroying fungi, together with other climatic factors con-
tributing to a long ripening season. The movement of Washington
Navels begins in November and ends in May. The Valencia crop is
marketed from May to November and, as a rule, overlaps by several
weeks the period when navels are shipped.
Frosty {21) reports that the Citrus Experiment Station of the
University of California, at Riverside, has recently introduced a
good early nonnavel variety, Trovita, wlrich has pollen and a few
seeds. This variety originated as one of three seedlings grown from
Washington Navel seeds accidentally found. It is pointed out that
this may be a promising variety in the hotter citrus districts because
of its seeding tendency, since the seedless Washington Navel often
fails to set fruit under these conditions. The fruit of the new variety
is much like that of Washington Navel, but the navel structure is
usually absent or rudimentary.
CITRUS FRUITS
773
Figure 10. — Tree of the Washington Navel orange at Riverside, Calif., the lone sur-
vivor of the original budded trees of this variety sent to California in 1873, propagated
from the introduction made in 1870 from Bahia, Brazil, by William Saunders,
Washington, D. C. A tablet in memory of Mrs. Eliza Tibbets, who first planted this
navel orange and brought it to fruiting, stands near the tree.
774
YEARBOOK, 1937
Figure 11. — Washington Navel orange fruit, typical of the variety as grown
at Riverside, Calif., showing solid but juicy pulp, locules separating easily,
firm, rather thick rind, small navel, and absence of seeds.
Texas
The commonly grown varieties of sweet oranges, along with other
varieties of citrus, were brought into the lower Rio Grande Valley of
Texas early in the twentieth century, but in general these are not as
CITRUS FRUITS 775
well adapted to the climate as the grapefruit. The most desirable
early to midseason variety of orange is the Hamlin. The trees are
prolific, regular bearers under lower Rio Grande Valley conditions,
maturing their fruit in October. Although the Pineapple is the most
widely planted early variety, the Weslaco substation of the Texas
Agricultural Experiment Station recommends that Hamlin and Joppa
should replace varieties such as Pineapple, Parson Brown, and Ruby,
which are characterized in Texas by the production of undersized
fruit and by erratic bearing habit (16). Even the desirable strains
of Washington Navel are not satisfactory, being "rather erratic in
their bearing habits" and producing juice "variable in flavor, often
being quite insipid (devoid of acid)." A recent introduction, one of
several navel oranges brought by the Department from Brazil and
now under test at the Weslaco substation, is very promising. It
has been named Texas Navel (fig. 12) and is being tried exten-
sively by growers. The tree is vigorous and somewhat more pro-
ductive than the strains of Washington Navel under Texas condi-
tions. The fruit is typically navel in structure, of medium size and
good quality.
The Valencia, which matures its fruit from December to January
under lower Rio Grande Valley conditions, is the "most profitable
commercial variety at the present time, since the trees are productive
and fairly regular in bearing, but a large proportion, of the fruit, which
are of good quality, is undersized."
The Temple orange, which belongs to the horticultural group of
high-quality hybrid fruits (tangelo oranges) and is similar to the
sweet orange, is promising under Texas conditions, but the rind texture
is unattractive and the tree is not hardy. In this same group
the Orlando, Seminole, Minneola, and Umatilla varieties are under
test.
As far as the standard varieties of sweet oranges are concerned,
none is entirely satisfactory under lower Rio Grande Valley conditions.
Louisiana
In the extreme southern tip of Louisiana on the Delta of the Mis-
sissippi, south of New Orleans, in the vicinity of Buras, a type of high-
quality nonnavel sweet orange of local origin has been grown for a
great many years along with some navels of recent introduction. The
annual output is usually about 300 cars, marketed primarily in New
' Grapefruit Improvement
The origin of the grapefruit as a horticultural citrus type is obscure.
It is apparently intermediate between the large acid shaddock and
the mild salad citrus type commonly referred to as the pummelo.
It was brought to Florida from the West Indies and does not corre-
spond to any type in the Orient. It was not appreciated until it
was brought to the attention of the consuming public in the 1880's
by enterprising Florid a citrus growers. It represents a most importan t
horticultural achievement, for it is now found on the breakfast table
in either the fresh or the canned state not only in the United States
but also in Europe, South Africa, and Australia.
776
YEARBOOK, 1937
Figure 12. — See legend on opposite page.
CITRUS FRUITS
777
Florida
The grapefruit industry in Florida was founded originally on
seedling trees, which are very much like the Duncan variety in struc-
ture and quality and are now known as Florida Common. The
original Duncan tree, over 100 years old in 1926, according to Hume
(82), was still living in the plant-
ing known as the Snedicor Grove
near Green Springs, in Pinellas
County, where it originated as a
seedling from a grapefruit tree
grown by a Spanish settler, Don
Philippe. Later reports are not
available. Duncan (14, V- 136)
stated in 1892 that Don Philippe
brought grapefruit and orange
seeds from Cuba 50 years pre-
viously and made his planting at
Safety Harbor in "Philippe Ham-
mock", and that the orange trees
died out from neglect while the
grapefruit trees remained in a
thrifty condition. The variety
was introduced and propagated
by A. L. Duncan, of Dunedin,
about 1 892. It is a very superior
variety. Although 17 or more
main varieties were later intro-
duced, Duncan remained the fa-
vorite among the seedy varieties.
Duncan and other seedy varieties
are now being top-worked to
Marsh in some instances because
of the demand for a seedless fruit.
Because of its seedlessness and
other desirable qualities the
Marsh variety has been gradually
replacing the seedy varieties in
plantings within the last 15 years. This variety originated in the
William 11 uncock grove at Socrum, near Lakeland, and was first cata-
loged by C. M. Marsh in the Catalogue of the Lakeland Nurseries for
Fall 1890 and Spring 1897, with the statement that the parent tree
was a seedling that had been a prolific bearer for 30 or 40 years.
Propagation evidently began some years before, as the parent tree
was killed in the freeze of 1894-95. A storv receiving credence in
Figure 13.— Egbert N. Reasoner (1869-
1926), pioneer nurseryman of Florida, ac-
tive in the introduction and propagation
of many subtropical fruits. He introduced
Foster, Thompson, Pernambuco, and Royal
grapefruit varieties and the Oneco tanger-
ine, initiated the commercial propagation
of the lychee, and was active in testing and
disseminating new varieties of mangoes and
avocados.
Figure I-. — The Texas Navel orange. A, Tree showing rigorous habit of this navel
variety, an inlroduction from Brazil made by the United States Department of Agri-
culture in 1917 when the Washington Navel proved poorly adapted to lower Rio Grande
Valley conditions. The tree has a height of 20 feet and a spread of 21 feet. B, Fruit
of the Texas Navel orange, which resembles the standard Washington Navel in physical
characteristics and quality but is more prolific under conditions in southern Texas.
Fruits average 2% inches in diameter.
188004° — 37 no
778 YEARBOOK, 1937
recent years that the variety originated as a broken root sprout from
a common seedy type tree has been definitely disproved by the
testimony of members of the Hancock family and other local residents
who were thoroughly familiar with the original seedling tree (56).
The Marsh variety has given rise to two pink-fleshod bud mutations.
A. D. Shame! has described one of these that originated near Riverside,
Calif., and was brought to his attention in July 1919 by L. V. W.
Brown. The mutation, that occurred in Florida, in the grove belonging
to W. B. Thompson near Oneco, was discovered by S. A. Collins and
introduced under the name of Thompson by Reasoner Bros. (fig. 13),
of Oneco, in 1924 (So). Both of these mutations are identical with
Marsh, except in flesh color. The Thompson variety, although not
extensively planted in Florida, has become an important variety in
the lower Rio Grande Valley of Texas.
The Foster, another pink-fleshed variety, originated as a branch
mutation 071 a tree of the Walters grapefruit. This occurred in the.
Atwood Grove near Palmetto, and was first observed in the season
1906-07. It was named and introduced by Reasoner Bros, in 1914.
Aside from the color, the fruit has much the same quality as the
parent variety, though it is sometimes regarded as earlier maturing.
The color of the pulp, as well as that of the Thompson, tends to fade
as the fruit reaches full maturity.
Another seedless grapefruit, the Davis, originating from a cross
between a seedling type of grapefruit and a tangerine (in the attempt
by Department workers to secure a tangelo) is receiving favorable
attention. In shape and size it resembles the Marsh, though it is
more rounded in form, but it has the taste quality of the seedy grape-
fruit, with apparently less glucosidal flavor than the Marsh. Its
outstanding character, however, is the fact that it has proved satis-
factory for canning, the pulp remaining firm, while the Marsh tends
to become soft from processing (34)-
In the improvement of grapefruit there has been a steady trend
toward the use of fewer varieties, and Marsh, largely because of its
seedlessness, has become the standard for new plantings, gradually
superseding the 17 or more other varieties — Aurantium, De Soto,
Excelsior, Hall, Josselyn, Leonardy, Manville, May, Bowen, McCarty,
McKinley, Inman, Pemambuco, Royal, Triumph, Walters, etc.
Texas
The Florida grapefruit varieties were introduced into California,
Arizona, and the lower Rio Grande Valley of Texas.
The grapefruit is apparently well adapted to the lower Rio Grande
Valley, and it has served as the basis of a citrus industry built up since
1910. As grown in the valley it has "a pleasing, mild flavor that has
met with favor in most of the markets where the fruits have been
offered for sale" (16).
Siich varieties as Duncan, Conner, McCarty, Inman, and Walters,
all seedy varieties, are grown to a limited extent for the early market,
but they are at a discount after the seedless variety, Marsh, is ready
for market. ■
The pink-fleshed varieties Foster (seedy) and Thompson (seedless)
have pink flesh early in the ripening season and usually sell at a
CITRUS FRUITS 779
premium. The Ruby, a local mutation from Thompson, has both
pink flesh and pink rind and is receiving some attention in recent
plantings. _ ,., . ...
California ana Arizona
The grapefruit industry in the Southwest began after the introduc-
tion of the Marsh grapefruit in 1890; the plantings of other varieties
previous to that time did not prove profitable. In the Arizona citrus
districts and in the Coachella and Imperial Valleys of California,
grapefruit matures fairly rapidly and is marketed in late fall and early
winter ; in other California grapefruit districts it does not reach full
maturity until the following spring or summer.
Mandarin Improvement
In the mandarin orange group the tangerine and satsuma oranges
are grown to supply special markets, primarily early in the season.
The chief breeding problem is in connection with the production of
high-quality early-maturing varieties.
Tangerine Orange
The only variety of tangerine orange extensively planted in Florida
is the Dancy, a prolific variety that was originated as a seedling by
George L. Dancy, of Buena Vista, St. Johns County, and was intro-
duced in 1871 or 1872. This variety is of great interest, since it is
the pollen parent of most of the tangelo oranges, and it imparts to the
best tangelos the deep orange rind and flesh color and the aromatic
and pleasing ester qualities. In Texas, although the earlier plantings
are mostly Dancy, the Clementine (Algerian) is decidedly superior to
this variety ,_ as is also the Warnuco (Ponkan) under lower Rio Grande
Valley conditions.
In California the Dancy is grown to a limited extent for special
markets, but apparently the small size and higher acidity developed
when it is grown in this section has retarded extensive planting.
Recently three mandarin varieties, developed by Frost (21 ) at the
Citrus Experiment Station, Riverside, have been introduced for pre-
liminary trial. They were originated as a first-generation cross between
the King orange and other mandarin oranges. In the case of the
Kara, the Owari satsuma was the seed parent, and in the case of
the Kinnow (fig. 14) and Wilking, the King orange served as the
seed parent and the Willowleaf mandarin was the pollen parent.
These varieties produce fruits of good size and excellent quality,
but, as pointed out by Frost, only orchard tests can determine their
ultimate value in citrus culture.
Satsuma Oranges
The satsuma orange was first introduced into Florida by George
R. Hall in 1876. In the upper Gulf coast region, from western
Florida to eastern Texas, it has been grown commercially since 1910,
and the industry is based primarily on the Owari satsuma. Although
there are apparently two or more strains of this variety, they do not
differ widely. The fruit is harvested early in the season, October and
November. It is desirable to harvest as early as possible for two
reasons- -to secure the early market before many high-grade sweet
780 YEARBOOK, 1937
oranges are shipped from peninsular Florida, and to remove the
fruits early enough to allow for the storage of maximum food reserves
in the tree before the onset of winter. In an attempt to meet this
need, the Department of Agriculture imported over 50 strains of the
early-maturing satsuma from Japan, and these are under test at the
Gulf Coast Substation at Fairhope, Ala., in cooperation with the
Figure 14. — The Kinnow mandarin, a hybrid of King orange and Willow leaf man-
darin, the King serving as the seed parent. The fruit is excellent in appearance and
flavor, remaining firm when fully ripe; desirable for local consumption but shipping
quality undetermined. Fruits shown are natural size, about 4Vi months after ripening.
Introduced by Frost, of the California Agricultural Experiment Station.
Alabama Agricultural Experiment Station and with growers in various
parts of this section. So far the Kawano variety has shown some
promise, but it does not uniformly mature earlier than the Owari.
Some of the other strains may prove more regular in this respect.
A selection from extra vigorous apogamic seedlings following cross-
pollination of the satsuma orange with the sweet orange is promising
from a commercial standpoint. The Silverhill variety, originated in
this manner, has now been tested for a number of years and appears
to be a superior strain of the Owari. It has shown somewhat more
resistance to cold than the other satsuma varieties, but the evidence
is not conclusive.
Improvement of Acid Citrus Fruits
The chief center of lemon culture is in California, and lime produc-
tion is confined primarily to Florida.
Florida
The introduction of the citrus scab proved a serious drawback to
lemon culture in Florida. There is also great difficulty in properly
curing lemons in the humid summer climate. In 1931 the Depart-
ment introduced the Perrine lemon (fig. 15), a hybrid between the
Genoa lemon and the Mexican or Key lime. It "is highly resistant
to citrus scab and anthracnose and has given a new impetus to the
industry.
CITRUS FRUITS 781
The Perrine lemon is a rapid-growing, vigorous, and productive
tree. The fruits are borne singly or in clusters and are of medium
size, with a high acid percentage, ranging from 6.2 to 7.2 percent,
ranking with standard commercial varieties in this respect (71, SO).
The Meyer lemon, an introduction from China named for the
introducer, the late Frank N. Meyer, famous plant explorer for the
Department of Agriculture, is chiefly noteworthy for its frost resistance.
Figure 15. — Typical fruits of Perrine lemon, a hybrid between the lemon and the lime;
remarkable for its resistance to scab and anthracnose, vigor of growth, and heavy
bearing. Resembles the true lemon in shape, size, and acid content. Introduced by
the United States Department of Agriculture.
Its low acid content (4.3 to 4.8 percent), large size, and round shape
preclude its general popularity as a commercial lemon, though it is
well suited to local needs where true lemons have proved too tender
The Key, Mexican, or West Indian lime has long been cultivated
primarily on the keys, but recently the industry has declined because
of hurricane damage. The Tahiti (also called Persian or Bearss)
lime has recently been planted to a considerable extent in Dade County
and the southern ridge section. It has high quality, and in addition
the aromatic properties of the rind are highly valued by the consumer.
The Lakeland and Eustis limes, hybrids of lime and kumquat, intro-
duced by the Department, although of high juice quality, are of small
size and have a thin rind, which may prove disadvantageous for
storing and shipping. „ ...
California
In the early development of the industry a large number of European
varieties of lemon were grown and also many seedlings were raised,
most of which were not promising. The present plantings are practi-
cally limited to Eureka and Lisbon. The former originated from a
seed planted in 1870 by C. R. Workmen in Los Angeles. The Lisbon
782 YEARBOOK, 193 7
variety originated in Europe. Shamel and coworkers (64) state that
the Lisbon lemon was introduced into California in a number of
importations, the first of which was made as budded trees in 1874
and 1875 from Australia. It has been pointed out that the advan-
tages of the Eureka are its comparative freedom from thorns, its
tendency toward early bearing, and its prolific bearing qualities.
The tendency to bear fruit on the tips of the branches and the inclina-
tion to grow long canes with but few laterals and to drop its leaves on
the long canes or branches, leaving the limbs and fruit too much
exposed to the hot rays of the sun, are disadvantages.
The Lisbon has heavy foliage, which protects the fruit from sunburn,
and the fruit is borne uniformly throughout the tree. This variety
has a tendency to bear one large crop maturing in winter, with only
a small amount of summer fruit.
MINOR CITRUS FRUITS
In the United States the pummelo, citron, kumquat, and sour orange
are not grown to any appreciable extent for their fruits. Of these
minor citrus fruits the pummelo is the most promising. The citron
is grown mainly for exhibition purposes, although a beginning has
been made in California with preserving it on a commercial scale.
The sour orange is grown as an important marmalade fruit in some
other citrus-producing countries, notably in Spain.
The pummelo in its better varieties is a most delicious salad
citrus. The juice does not possess the sprightly acid and naringin
(bitter) properties of the grapefruit, but when the 'juice sacs are served
as a salad the inimitable flavor is relished by all who have had the
good fortune to sample them. In timespast only the sour shaddock
was known in the citrus-producing districts, but since 1915 the
Department of Agriculture, through its collaborator, G. Weidman
Groff, in China, has introduced an important collection of pummelos.
These are not as yet well known but are being distributed to those
interested in the culture of the fruit. One of the outstanding varieties
is named Siam. Reference to this collection will be found in table 5.
The Department has also imported a valuable collection of citron
varieties, including practically all of the important ones. Corsican,
the chief varietyof commerce, was one of the first citrus introductions
made by Fairchild, who was for many years in charge of the plant
introduction work of the Department.
Kumquats were introduced into Europe as recently as 1846 by
Robert Fortune. Importations into the United States were made by
Taber in 1 885 and Reasoner in 1885 and 1890. The varieties Nagami
(oval) and Marumi (round) were first introduced, and later the Meiwa
or sweet kumquat. The Nagami predominates in all plantings made
thus far. About 1910 the Department introduced the Hong Kong or
wild kumquat, which produces very _ small round fruits and is of
interest from the breeding standpoint in that it has the double haploid
chromosome complement. (See the later section on cytology in this
article.)
The Department has introduced a superior variety of sour orange
named Oklawaha. It originated as an apogamic seedling when pollen
of the shaddock (sour pummelo) was used to pollinate the sour orange.
CITRUS FRUITS 783
In habit the tree appears as a vigorous sour orange. _ The fruit is
similar to the ordinary sour orange but averages larger in size, 3 to 4
inches in diameter, and it is superior to the ordinary seedling sour
oranges as a marmalade variety.
CITRUS BUD SELECTION
With the general acceptance of De Vries' mutation theory (1901), the
improvement of varieties by the selection of bud mutations soon
became a recognized mode of procedure hi plant breeding. Con-
versely, the elimination of inferior bud mutations became of equal or
even greater importance in many clones especially subject to mutations.
That the Washington Navel orange is subject to bud mutation
was recognized at an early date, and by 1910 the problem was so
serious that at the California State Fruit "Growers Convention of that
year Coit (10) proposed to "keep individual tree records for 2 years
and these trees with records to be offered nurserymen for propagation
as pedigreed trees." At the same meeting Coit, in discussing the
application of the De Vries mutation theory to the problem, said:
If you go out into the average navel orchard to select a dozen perfect navel
oranges true to old standards, you will be surprised at the amount of searching
necessary. * * * It is my belief that by far the greatest part of the divergence
is attributable to mutation * * *.
He added that propagators —
must l)e quick to see and cut out all branches sporting toward poor types. In the
second place, we must be exceedingly careful in cutting budwood. * * *
Select buds from those branches which produce your ideal of the navel orange.
The problem was so serious that the Department of Agriculture
detailed A. D. Shamel to study it in 1909, and he began his work in
cooperation with the California Citrus Experiment Station at River-
side and with citrus growers. In his first report entitled "Bud Selec-
tion in Citrus Fruits", given at the California State Fruit Growers
Convention at San Bernardino, March 8, 1911, Shamel set forth the
problem clearly. His work began with the Washington Navel and
was extended to include other sweet oranges, the lemon and grapefruit
types, as well as other crop plants.
" Over a period of 27 years the work of Shamel and his coworkers
(57, 58, 59, 60, 61, 62, 68, 64) has been characterized by consistent,
painstaking research, which has included a study of the source of
strains originating as bud mutations and unintentionally propagated
by nurserymen and growers. This was followed by efforts to eliminate
the inferior trees in established plantings by top-working with carefully
selected buds. Further efforts were made to avoid the propagation of
undesirable strains arising from bud mutations by systematic selection
on the basis of individ ual plant performance and an intimate knowledge
of the plants. Finally, a systematic search was made in cooperation
with growers for superior plants originating from commercially valua-
ble bud mutations, and these were tested in progeny plantings to single
out the ones inherently superior to the parent forms for utilization by
the industries concerned.
In the case of Washington Navel orange it has been shown (61, p.
67) on the basis of individual performance records made in several
California groves since 1909 that—
784 YEARBOOK, 1937
those groves consist of at least 20 strains of commercial importance with five or
more others of less economic consequence. The trees of each of these strains have
fruit or vegetative characteristics, or both, which serve to distinguish them from
all other trees of the variety.
About 25 per cent of the total number of trees studied in the original orchards
in which these investigations have been conducted were found to be of undesirable
strains having consistently low yields, or bearing fruits of poor quality, or both,
such as those of the Australian, Unproductive, Corrugated, Pear-Shape, Sheep-
nose, Flattened, Dry, and other inferior strains.
The extent of the commercial use of superior strains selected for the
production of more uniformly good fruit is indicated by the sale of
selected buds by the Fruit Growers Supply Co. for the period 1917-35.
These data, given below, include only a part of the supplies of such
buds used by nurserymen and growers — probably not more than 50
percent; but because they are conservative they will the better convey
some idea of the value of this kind of work.
Number of
Name of strain buds sold
Superior strain of the Washington Navel orange _ . 1 , 402, 950
Superior strain of the Valencia orange . . — 2, 338, 004
Superior strain of the Marsh grapefruit 1, 262, 757
Superior strain of the Eureka lemon .. 766, 950
Superior strain of the Lisbon lemon . _. 86, 215
Superior strains of miscellaneous citrus varieties 66, 886
Two special citrus strains originating as bud mutations, the Robert-
son Navel orange in 1925 and the Dawn grapefruit in 1929, are now
being introduced, and the indications are that they will be widely
grown in certain citrus districts of California and Arizona. In the
Robertson Navel orange strain the fruits are resistant to June drop on
account of their very rapid early growth. They mature about 1
month earlier than those of the Washington Navel orange under com-
parable conditions, and the trees are more productive than the normal
Washington Navel. Otherwise the mature fruits of the Robertson
strain and those of the parent variety are very similar and cannot be
distinguished even by those who have grown and studied them.
The Dawn is a strain of the Marsh grapefruit in which the fruits
mature about 1 month earlier than those of the parent variety, and the
trees are unusually productive. Otherwise the Dawn and the Marsh
trees and fruits have similar characteristics. The indications are that
this strain will be a particularly valuable one for growing in the desert
grapefruit-growing districts.
Many other citrus bud mutations are under test in cooperation with
growers in California and Arizona, and some of these promise to be of
commercial importance in the near future.
In the history of subtropical fruit breeding the work of Shamel, his
coworkers, and the California Agricultural Experiment Station co-
operators is inspiring. It is characterized by consistent, painstaking
research and unwavering purpose. In the earlier years, although the
work was fully appreciated by the growers in the region, scientific
workers elsewhere did not give entire credence to the remarkable
evidence uncovered. As time went on, Shamel and his coworkers
answered their critics by applying statistical methods to the data,
which gave convincing proof of the conclusions. Later, numerous
bud mutations were also discovered in other fruit typos, including
apple, and by the time the work was no longer challenged the results
CITRUS FRUITS 785
achieved stood out as monumental in this particular field of research.
The practical benefits to the industry can be gaged by the millions of
selected buds that have been used by the citrus growers in California
and elsewhere. A summary of the bud mutations and strains isolated
by Shamel and his coworkers is to be found in table 8.
In Florida a bud-selection project has been in progress since 1921.
The mode of procedure differs somewhat from that followed in Cali-
fornia and was developed cooperatively by the Florida Agricultural
Experiment Station and the Department of Agriculture. At the
Lake Alfred Citrus Experiment Station a progeny grove has served
as the basis of variety improvement. In this progeny grove standard
varieties of oranges and grapefruit are represented bjT rows budded
from parent trees of known production,, several such selected parents
being included for each variety. Production records have been kept,
and a detailed study of fruit characteristics has been made as the basis
for reselection among the original progenies. For purposes of com-
parison a few off type progenies have been included, which have served
well to illustrate the importance of careful bud selection in nursery
propagation. Growers and nurserymen have gradually come to realize
the value of such true-to-type budwood, which has been made available
through the experiment station for several seasons past at a cost not
greatly in advance of common commercial rates.
Other bud mutations of value to the citrus industry are Foster,
Thompson, Ruby, and Davis grapefruit (described above), Silverhill
satsuma orange, and Oklawaha sour orange, the three latter being
seedling or nucellar mutations.
ROOTSTOCKS
A number of citrus types and varieties are of major importance be-
cause of their value as rootstocks for the varieties grown commercially.
In the early development of the citrus industry, especially in Florida,
seedling citrus trees were extensively planted, but gradually this prac-
tice was discontinued, as it was realized that certain rootstocks were
better adapted to the soil conditions. This advance was made by the
expensive trial-and-error method, and the stage reached by the 1890's
was recorded by Van Deman {81). Planned experiments with root-
stocks have been relatively rare. In California, Mills (46) has reported
results secured at the experiment station at Pomona, and Bonns and
Mertz (3) described the experiments carried out at the Citrus Experi-
ment Station at Riverside. The important work of Webber (85) at
the citrus station is an illuminating piece of research into the seedling
variation of the types commonly used as rootstocks. Unfortunately,
the work of Taber (fig. 16) quoted by Hume (31 , pp. 209-218) at the
Glen St. Mary Nursery in Florida was discontinued too soon. Traub
and Friend (77) have reported on preliminary experiments in the
lower Rio Grande Valley of Texas. Akenhead, Feilden, and Hatton
(1) have recently summarized the investigation on citrus rootstocks.
As indicated, the horticultural utilization of rootstock types is
based at present mainly on the knowledge accumulated through
many years of trial and error. The final results are very valuable,
though they were secured at great economic expense. The entire
field has not been exhaustively explored.
786
YEARBOOK, 193 7
In general it may be stated that in Florida, as pointed out by
Camp (4), the root-stock problem is more complex than in the lower
Rio Grande Valley of Texas, in California, or in Arizona.
Three major considerations are necessary in the choice of suitable
rootstock — congeniality between stock and scion, resistance to
diseases, and adaptation to the soil and climatic conditions. Root-
stocks have been tested over a
considerable period by commer-
cial growers, and at the present
time only three are extensively
used — sour orange, rough lemon,
and the trifoliate orange. The
Cleopatra mandarin has recently
received some attention as a root-
stock. In Florid a, trees on grape-
fruit stock grow vigorously in the
early stages but usually prove to
be shy bearers and show decline
after a number of years. Sweet
orange is susceptible to foot rot,
and both grapefruit and sweet
orange are less cold-resistant than
sour orange. The commercial
lemon is susceptible to diseases,
and trees on it are short-lived.
The citrange has been tried as a
substitute rootstock in place of
the trifoliate orange for the
satsuma orange, but recent obser-
vations have shown that the cit-
range is not reliable in the Gulf
coast region, since it is evergreen
and does not go dormant suffic-
iently during the winter season.
This has resulted in the loss of
the scion variety in some seasons.
Figure 16. — George Lindley Taber (1854-
1929), pioneer nurseryman of Florida, who
demonstrated the limitation of the satsuma
orange to trifoliate orange stock, founding a
new industry; introduced Duncan grape-
fruit, Lue (rim Gong sweet orange, and varie-
ties of persimmons, and cooperated with the
United States Department of Agriculture
in the production of early citrus hybrids.
The sour orange is a useful
stock in all citrus-growing regions
except South Africa, where all attempts to use it so far have failed.
It is compatible with most citrus types except satsuma, kumquat,
and lime. In California, lemon trees on this stock may show decline
after 10 to 20 years, which has been attributed to the stock. For
this reason many of the recent lemon plantings in California have
been budded on the sweet orange. The sour orange is highly resistant
to cold and to root and crown bark diseases, but highly susceptible
to citrus scab. Roots are deeply penetrating, and the stock is well
adapted to clay subsoils and wet or heavy soils. In Florida it is
successful on moist hammock as well as on moist flatwoods soils
and on the heavier soil types in general. In California. Arizona, and
the lower Rio Grande Valley of Texas it tolerates irrigation conditions.
This, together with its adaptability to southwestern conditions, has
miu]e it the rootstock almost universally used in these regions. Its
CITRUS FRUITS 787
main drawback is its relatively slower growth on light soils as com-
pared with rough lemon, but on heavier soils the rate of growth is
satisfactory.
The rough lemon (Citrus limonia) makes a _ satisfactory growth
even on very light and sandy soils. This makes it valuable in certain
sections of peninsular Florida. It is highly susceptible to citrus scab
and susceptible to foot rot and other root and crown diseases, b\it
this apparent handicap is minimized, for on sandy soils these diseases
are less troublesome than on the heavier ones. It is extensively used
as a rootstock for citrus on soil types not suitable for sour orange in
Florida. It is not well adapted for use with the satsuma orange,
producing coarse, raggy fruit.
The trifoliate orange was once recommended as a rootstock for
citrus in the lower Rio Grande Valley of Texas (48), chiefly on account
of cold resistance; but it proved susceptible to foot rot and cotton
root rot and was later discarded in favor of the sour orange (77). In
the upper Giilf coast region it is universally used as a root stock,
since it is deciduous and goes more dormant during the winter season
than evergreen citrus types. It is the hardiest of the citrus types.
Recently the Cleopatra mandarin has been recommended as a root-
stock in place of rough lemon, chiefly on the basis that it is more
cold-resistant than the rough lemon and tends to produce better
textured fruit, holding fruit later in the season in good condition. It
is immune to scab and resistant to gummosis. However, experimen-
tal work has not been carried out extensively enough to warrant
unqualified recommendation.
It has already been pointed out that most citrus seeds produce more
than one. seedling, and that any extra seedlings not of seminal origin
are produced by budding from the mother plant tissue. On the sur-
face it would appear that this is an ideal condition from the standpoint
of seedling rootstock production, since it would< give a large per-
centage of plants like the original stock, and this is true in the main.
Webber (85) and Frost (20) have shown, however, that variations
may occur even among such nucellar seedlings. Frost points out the
influence of mutations in this connection. The work of Webber is
of special interest. His experiments, which were started in 1914,
show that —
citrus seedlings of the species and varieties most commonly used as rootstocks
exhibit a wide range of variation. In any lot of seedlings grown from seed of the
same variety and from the same source, the great majority usually are of the same
general type, but from 5 to 40 per cent of them are highly variable types which
apparently differ in genetic constitution from the prevailing type and from each
other.
These variants .may include both apogamic and seminal seedlings.
They are usually small and lacking in vigor and when used as stocks
induce dwarfing of the tree. His experiments show that small seed-
lings and "small budlings tend to produce small, low-yielding orchard
trees; and that large seedlings and large budlings tend to produce
comparatively large, high-yielding orchard trees." In order to secure
the desired uniformity in orchard trees, Webber advises "a moderate
culling of small seedlings at the seed bed, followed by a careful roguing
and destruction of all variants and small seedlings in the nursery just
prior to the budding."
788 YEARBOOK, 1937
CITRUS IMPROVEMENT IN FOREIGN COUNTRIES
This section, like the similar sections in connection with other sub-
tropical fruit crops, is based almost entirely on replies received to the
questionnaire dealing with the Cooperative Survey of Plant and
Animal Improvement. The information received mainly concerns the
present and future objectives of breeders.
Mexico
Citrus studies are carried on at experiment stations of Montemore-
los, Nuevo Leon; El Yaqui, Sonora; and Emporio Macuspana, Ta-
basco. Infestation of fruit by the orange maggot, Anastrepha ludens
Loew, constitutes the most serious problem. Methods of attack are
being studied, but without practical results thus far.
South America
At the Institute Agronomico do Estado de Sao Paulo in Brazil, work
with citrus under the direction of C. A. Kruge, head of the genetics
department, is being confined primarily to the improvement of varie-
ties by bud selection and to the improvement of the sour orange
rootstock by making extensive progeny tests. The disease resistance
of rootstocks is also being studied.
In Chile no breeding work with subtropical fruits is under way at
the experiment stations, but Salvador Ezquierdo at Santiago has for
many years introduced varieties of citrus, avocados, etc., to test their
adaptability to Chilean conditions.
At the Estacion Experimental de Concordia, Argentine Republic,
Signor Ruben Bence Pieres, director of the station, is conducting ex-
periments with citrus which concern the selection of sour orange
seedlings, with a view to obtaining strong, vigorous, fast-growing
plants. A naturally occurring hybrid mandarin named Malvasio,
with a large fruit, fine rind color, excellent quality, and late maturity,
is being tested and shows promise of commercial value. The main
introduced varieties, which have been selected from a large number
and are being extensively cultivated, are the Marsh and Qurian grape-
fruit and the Valencia and Lue (Lue Gim Gong) sweet oranges. The
cultivated area of grapefruit and sweet oranges approximates 5,000
acres, with about half devoted to each type. The main problem that
confronts the citrus industry is the ravages of foot rot. Work is in
progress for the selection of resistant stocks, as indicated above.
Europe and North Africa
At the Estacion Naranjera de Levante at Burjasot, Valencia,
Spain, work has been carried on in sweet orange breeding since 1927
under the direction of Manuel Herero. The work has been confined
mainly to selection from open-pollinated seedlings of Washington
Navel. Two improved varieties have been selected, one round and
the other oval in form. These are being cultivated to the extent of
about 375 acres. Hybridization work was begun in 1932 and is being
carried on to the second generation after crossing. The crosses made
are those between the sweet orange and the mandarin.
A. Bixaghi, pathologist, Italian Department of Agriculture, Rome,
reports that the chief problem with citrus culture in Sicily is in con-
CITRUS FRUITS 789
noction with the disease mal secco, chiefly affecting lemons. At-
tempts are being made to breed varieties resistant to this disease.
Two resistant lemon varieties of unknown origin and not desirable for
cpiality have been found locally, and promising varieties have been
imported from India (2) and the United States for use in breeding
experiments.
At the Superior School of Agriculture, Laboratory of Horticulture,
Athens, Greece, P. Th. Anagnostopoulos has gathered together a
collection of citrus species for selection and breeding work.
In Morocco, under the leadership of F. Lacarelle, director, and
Ch. Miedzyrzecki, geneticist, Experimentation Fruitiere et Marai-
chere, Rabat, citrus fruit improvement is being studied through several
methods: (1) Bud selection, (2) hybridization to secure improved
varieties and varieties resistant to disease, and (3) selection of stocks.
The varieties receiving the most attention are Washington Navel,
Valencia Late, and Clementine. A special study of the seed content
of the Clementine led to the conclusion that seed production is largely
dependent on the proximity of other varieties, especially of mandarin
oranges, to furnish pollen to the flowers of the Clementine, self-
fertilized flowers being almost seedless (38, 89).
Asia and Malaya
At the Jewish Agency Agricultural Research Station, Rehoboth,
Palestine, the experimental work was started by J. D. Oppenheim and
is now being continued by Ch. Oppenheimer. The work is confined
primarily to improvement by bud selection, which was begun in 1934,
and by hybridization, begun in 1933. The first-generation hybrids
have not reached fruiting stage. The hybrids are from crosses of
the Jaffa orange with other early and late varieties, of the blood orange
with the tangerine, and of the sour orange with the sweet lime. The
station has gathered together a collection of about 70 citrus varieties.
Theoretical studies are under way on the inheritance of peel
thickness in citrus and on the effect of pollination on number of
seeds.
At the Imperial Horticultural Experiment Station at Okitsu,
Japan, T. Tanakawa is carrying on investigations in bud variation in
early- and late-maturing satsuma oranges. Sixty-one late strains and
42 early strains are being tried out. The work was started in 1925
and is still in progress. Citrus hybridization work was begun in 1909.
Tyozaburo Tanaka, professor of horticulture at the Taihoku
Imperial University, Taiwan, Japan, is engaged in citrus breeding.
Kimijiro Noro, pomologist at the Shizuoka (Japan) Agricultural
Experiment Station, has made a collection of 80 bud mutations of the
satsuma orange.
At the Department of Horticulture, Lingnan University, Canton,
China, G. Weidman Groff. professor of horticulture, and Pui-Man Lei,
Qu-Nin Shiu, and A. N. Benemerito, pomologists, have gathered
together a comprehensive citrus collection for use in the selection of
desirable types of citrus and citrus relatives, particularly from the
south China area, with numerous introductions from abroad. Some
of the systematic work on this collection has been carried out in collab-
oration with the United States Department of Agriculture.
790 YEARBOOK, 1937
K. D. Fordham, deputy director of gardens, United Provinces,
Saharanpur, India, reports that citrus rdotstock trials are under
way, including Khatta (Kama lime), Citrus Hmonia, Sylhet, Bijori,
Sadaphal, Jamberi, Bilhari, G algal, Sweet Galgal, Turanj, and sweet
linie.
B. Nazareth, superintendent, Modibag Garden, College of Agri-
culture, Poona, India, reports that studies of mutations occurring in
the principal citrus varieties, Santra Mosambi and Ladoo, have been
made, and many well-marked sporting forms have been recognized.
Breeding work thus far has been confined to mass selection both for
rootstocks and for scion varieties. Collections of scion and rootstock
varieties are being made to initiate systematic breeding of fruit crops
adapted to different soil and climatic conditions. Attempts at hy-
bridization made in 1912, 1914, and 1918 gave negative results.
Polyembryony in citrus lias been studied, showing varying percentages,
from none in the pummelo to 60 percent in the Ladoo orange. The
Marsh (seedless) grapefruit has been introduced for culture in the
Bomba-v region. ~ „ .
South and Central Africa
The Department of Agriculture, Zanzibar, East Africa, is studying
local and imported varieties of citrus in a series of plots. This work
is being carried out by A. Q. Findley, director.
Australia and New Zealand
At the Department of Agriculture and Stock, Brisbane, Queensland,
bud selection of citrus has been practiced for many years and Govern-
ment certified bud wood is available for nurserymen. The chief sweet
orange varieties grown are Washington Navel, Valencia, Jaffa, Sabina,
and Joppa. The lemon varieties are Lisbon and Villa Franca. The
mandarin varieties are Beauty of Glenn Retreat, Emperor of Canton,
Scarlet, and Fewtrel Early. The grapefruit variety is Marsh, and
Seville sour orange is grown for marmalade. Sour orange and rough
lemon rootstocks are used for citrus except that mandarin is grown
on mandarin.
At the Department of Agriculture, Division of Horticulture, Mel-
bourne, Victoria, J. M. Ward, superintendent of horticulture, has
carried on work in bud selection since 1931, and up to the present
one variety has been propagated' — a thin-skinned early navel orange,
which has not as yet been named. The department also supplies
buds of selected strains of the Washington Navel and Valencia
to growers and nurserymen. No work in hybridization has yet been
carried out.
At the Department of Agriculture, Division of Horticulture, Well-
ington, New Zealand, J. A. Campbell, director, has gathered together
a representative collection of citrus species and varieties for intensive
study.
H. Wenholz,^ director of plant breeding, Department of Agriculture,
New South Wales, Australia, reports that citrus breeding is being
carried on at the Grafton Experiment Farm and the . Hawkesbury
Agricultural College with the object of producing "a late hanging
navel orange" and a late Valencia of fine texture. A cross has been
made between Valencia and a very fine-textured seedling variety.
CITRUS FRUITS
791
TECHNICAL PROBLEMS AND RESULTS
IN CITRUS BREEDING4
Progress in genetic research has been greatly retarded on account
of the common occurrence of polyembryony in most citrus types,
which makes it necessary to grow to the fruiting stage large numbers of
lei
Figure 17. — Embryo development and "nucellar embryony" in Citrus and Poaeirus,
after Osawa (50): Nos. 72, 80-85, trifoliate orange; 73-76, sat sum a orange; 77, Wash-
ington Navel orange. (Original magnifications changed to conform to present reduc-
tion.) 72, Two-nucleated embryo sac, X 570. 73, An ovule showing embryo sac,
nucellus, and inner integument, X 175. 74, Details of embryo sac of no. 73, with
four nuclei, X 570. 75, Embryo sac with eight nuclei, X 570. 76, A mature embryo
sac with egg apparatus, polar nuclei, and antipodal cells, X 570. 77, The same, X 570.
80, Micropylar portion of an embryo sac, showing fertilized eggs, pollen tube, and
endosperm nuclei, especially some large nucellar cells containing large nucleus and
much cytoplasm, X 175. 81, The same, X 265. 82, Micropylar portion of an embryo
sac showing two-celled embryo and endosperm nuclei, X 175. 83, An older ovule,
showing embryo sac, embryo, endosperm nuclei, nucellus, and integuments, X 20.
84, Upper portion of embryo sac of no. 83 more magnified, showing six-celled embryo,
endosperm nuclei, and nucellus, X 175. 85, Upper portion of an embryo sac, showing
polyembryony, X 370.
seedlings that have arisen asexually. That this section is not more
complete is due in the main to this one cause. Even the grouping of
citrus species {68) is complicated by this condition.
1 The following sections are written primarily for students and others professionally interested in genetics
or brecdina.
792
YEARBOOK, 1937
Cytological Basis for Citrus Genetics
A study of the chromosome numbers and chromosome behavior in
citrus is basic to a consideration of citrus genetics. According to
Frost (20), it may be assumed that bud-variation types originate pri-
marily either as gene (point) mutations or as chromosomal aberrations,
and an understanding of these fundamental facts may also throw-
some light on the great variability
of Fi hybrids between species.
Strasburger (66) determined
the haploid chromosome number
as 8 in the sweet orange (Citrus
sinensis), the sour or bigaradc
orange (C. aurantium), and the
citron (C. medico). Osawa (50)
reported that the haploid chro-
mosome number in the satsuma
orange (C. nobilis var. deliciosa)
was probably 8 (fig. 17).
In 1924-25 both Frost (fig. 18),
at the Citrus Experiment Station,
i ^B Riverside, Calif., and Longley, of
^^^^W the Department of Agriculture,
jm^ WL ^^^ reported important work on the
BK- cytology of citrus. Frost (18) de-
termined the chromosome num-
bers in two varieties of sweot
orange (Citrus sinensis) and one
variety of grapefruit (C. grandis),
and in each case thehaploid num-
ber was 9. He observed neither
polyspory nor polycary.
Longley (4-5) made chromosome
counts in 24 citrus species and
citrus relatives and verified the
basic chromosome number of cit-
rus as 9, but he also found 1 tetra-
ploid species, the Hong Kong kumquat (Fortunella hindsii (Champ.)
Swingle). He observed both polyspory and polycary in many forms.
He states that "irregularities in chromosome pairing at diakinesis and
in their distribution at meiosis were frequently noticed. The outcome
of such irregularities was the presence of tetrads containing more than
the expected four pollen grains." In grapefruit, limes, and limequats
polyspory was often observed. He points out that there may be "a
relation between irregular chromosome numbers and the production of
citrus with supernumerary chromosomes." According to Longley, two
factors, however, may hinder the spontaneous appearance of such poly-
ploid forms — the possibility that only sex cells with 9 chromosomes
are viable, and the infrequent use of seeds as a means of propagation.
However, in the early histoiy of citrus culture, seedlings were com-
monly used in planting groves, and the disappearance of polyploid
forms is apparently because they are of little or no value in horticul-
\MT\
Figure 18. — Howard H. Frost, associate
plant breeder, California Agricultural Ex-
periment Station, since 1912, has made ini-
|>ortant contributions to the cytology and
genetics of citrus and is the originator of
the Kara, Kinnow, and AX'ilking mandarins
and the Trovita sweet orange.
CITRUS FRUITS
793
ture, as Frost points put. Longley emphasizes the possible value of
the tetraploid Fortunella hindsii in hybridizing with closely related
diploid forms to increase the chances of obtaining forms with un-
usual chromosome complexes.
Later, in 1925, Frost (19) reported on the discovery of certain
"thick-leaved" apogamic seedlings of sweet orange (Citrus sinensis)
and lemon (C. limonia) which
proved to be tetraploids. He had
observed such types to the extent
of several percent of the total
progeny in some cases in 12 horti-
cultural varieties of citrus, repre-
senting 4 species, and in 2 botan-
ical varieties, and he points out
that they also may prove to be
tetraploids.
As to the cause of these forms,
Frost postidated the possibility
of "islands" of tetraploid tissue
in the parent trees, so that not all
tetraploid seedlings represent dis-
tinct doubling of chromosome
number. Against this view he
found that the thick-leaved forms
have not been found in mature
trees by Shamel and his cowork-
ers, and stated that this might
be due to "the slower growth of
tetraploid cells which might keep
them from multiplying sufficient-
ly to dominate the apical meri-
stem, rather than to failure of
tetraploidy to originate outside
the nucellus." He further sup-
ported the hypothesis by citing
the fact that in many cases a
thick-leaved seedling has develop-
ed from a seed giving two or more
nonhybrids, and in such cases the other apogamic seedlings from
the same seed have almost always been normals.
In connection with these thick-leaved forms, Frost pointed out
that they have not given promise of direct horticultural value, but
they may be an aid in producing triploids or modified triploids by cross-
ing with ordinary diploid forms, and that triploids would probably be
practically seedless.
In 1926 Longley (45) reported his findings with reference to a
triploid trigeneric hybrid, produced by Swingle and coworkers of the
Department of Agriculture. This is a cross of the limequat (Fortu-
nella margarita Swingle X Citrus aurantijolia) with Fortunella hindsii.
Longley found 13 bivalent and a single univalent chromosome as the
reduced number, and he found indications of only slight irregularity
in chromosome distribution during meiosis in the triploid plant.
Figure 19. — Herbert J. Webber, pioneer
worker in breeding citrus and other crops;
United States Department of Agriculture,
1892-1907; Cornell University, 1907-12;
California Agricultural Experiment Station,
since 1913. He has carried on important
work on rootstock variation as influenced
by polyembryony.
K(8904°— 87-
-31 ++
794
YEARBOOK, 1937
These findings led. him to believe that triploids may be produced by
appropriate crosses, and that in the case just cited or similar crosses
there is a possibility of producing a seedless kumquat. More recently
Longley* has found a second triploid, a sister hybrid of the first
triploid found. Since most triploid plants are sterile, such crosses,
it is hoped, may lead to developing seedless fruits. Longley later
(April 1928) found an individual of Triphasia trijolia P. Wilson having
18 chromosomes.8 _
POLYEMBRYONY
In 1719 Leeuwenhoek noticed two embryos in orange seed, but it
was not until 1878 that Strasburger (65) explained the true nature of
the phenomenon of polyembryony in citrus as sporophytic budding
from nucellar tissue. Frost (19) in 1925 found that in a minor por-
tion of nucellar embryos— less than 1 percent — two hybrids were pro-
duced from one seed. Instances have been noted of three and even
four — only two cases of the latter — apparently true hybrids produced
from a single seed.6 In one instance (lemon X trifoliate orange) out
of 782 seeds, 16 produced 2 hybrids from 1 seed, with 1 producing 3
and 1 producing 4 hybrids, which is slightly more than 2 percent of
"doubling."
Webber (88) (fig. 19), Frost (20), Toxopeus (74), and Torres (78)
have shown that citrus types vary widely in the percentage of nucellar
embryos produced (fig. 17). In a recent study made by Torres in
the Philippine Islands, based on 50-seed samples, only the pummelo
type did not exhibit polyembryony (table 2).
Table 2. — Polyembryony in citrus in the Philippine Islands
Citrus type
Pummelo
Grapefruit-. ,
Sweet orange
Citrus nobitis
Lemon
Average embryos per
seed (range within type)
Number
1.0
I. 16±0. 23 to2.80±0. 89
l.32± .002to4.88±l. 12
l.02± .07 to 2. 72± .44
1. 30± . 28 to 2. 90± . 88
Krnbryos
per seed
(range-
minimum
and maxi-
mum)
Citrus type
Average embryos per
seed (range within type)
Nuviber
lto 6
lto 12
lto 6
lto 6
Number
Sour orange..-. 1.00 to 1. 18±0. 18
Lime 1 1.0 tol.20±.18
Tangelo 1.92± .4f> to2.32± .42
Calamondin.-.! 5.32±,88
Embryos
per seed
(range-
minimum
and max-
imum)
Number
lto 3
lto 2
1 to 4
1 to 10
After summing up the evidence with reference to the effect of polli-
nation on polyembryony, Frost (20) stated that it appears "very
probable that citrus seeds do not develop without pollination, although
seedless fruits sometimes develop without pollination even in varieties
normally seedy." This would indicate that nucellar budding, which
produces apogamic embryos, is at least very largely dependent on
some growth stimulus due to the fertilized egg, as suggested by
Strasburger (66) and Webber (84).
Frost (20) has shown that in interspecific crosses there is a negative
correlation between the total number of seedlings and the percentage
of hybrid seedlings, which shows the possible effect of competition
among the embryos within the seed. During such developmental
s Unpublished work.
6 Unpublished results of Swingle's crosses in 1909.
CITRUS FRUITS 795
selection acting within the soma of the parent, the fertilized egg may
be crowded out by the apogamic embryos, depending on the number
of apogamic embryos that start and on the position and relative age
and vigor of the two classes of embryos. Evidence as to selective
elimination during germination was secured by noting the difference
between the number of dissected embryos and the germination per-
centage in similar lots. During germination, survival may be deter-
mined by the "difference in size, vigor, position, morphological com-
pleteness, and susceptibility to infection." It was also noted that
albinism causes the early death of many seedlings from some parents.
The variation in the number of nucellar embryos produced within
a variety, and the possible effect of environmental conditions on such
variation, led Traub (76) in 1936 to offer the hypothesis, based on pre-
liminary experiments, that the number of nucellar embryos produced
might be artificially varied by difference in food supply. If the pre-
liminary results can be firmly established by experiments now in
progress, an effective method for use in breeding work would be pro-
vided.
Swingle (69) postulated that citrus varieties propagated as clones
are subject to senescence with age, and he cited the supposed dis-
appearance or reduction in size of spines in well-established clones
as one of the clearest indications of such senescence. He claimed
that such clones might be at least partly rejuvenated, that is,
become more spiny and vigorous, for instance, when seedlings from
nucellar embryos were used as a method of establishing a new clone.
This supposed nutritional effect of the embryo sac on the nucellar
embryo developed within he named the "new-life" or "neophyosis"
hypothesis.
However, there are no facts to prove that citrus clones are subject
to senescence, and it is questionable whether the supposed rejuvenation
is explainable as a permanent genetic factor change due to a nutritional
effect or may be better explained by Frost's (20) theory of "islands"
of mutating tissue in the nucellus.
Evaluation of Breeding Methods
Mass selection from open-pollinated seedlings was the method of
citrus breeding followed by the early citrus growers. It has yielded
important results over long periods, but it is not now followed by any
of the United States workers in this field. The search for bud varia-
tions and the use of hybridization are so much more promising that
the method will be revived only for use in special cases.
The practical bearing of a rapid mutation rate in citrus has already
been discussed in detailing the improvement of varieties. The
question of the cause of such variations remains to be considered. It
has been pointed out that Frost had postulated islands of tetraploid
nucellar tissue as a possible explanation of the variation in apogamic
seedlings, and the little that is known as to the cytological basis of
citrus bud mutations has been ably discussed by Frost (20). The
worker in this field does not have a background of abundant experi-
mental data and must make use largely of the principles established
by workers with more facile plant material such as maize, Nicotiana,
etc.j in developing useful theories.
796 YEARBOOK, 1937
On this basis Frost _ summarized the situation. Bud variations
presumably originating in single cells by gene mutation or by differen-
tial mitosis are frequent in citrus. Frost says:
In the former case, at least, their somatic expression is doubtless favored by the
presence of numerous heterozygous recessive genes. The production of recogniz-
able bud variations, then, requires bud formation in an area of variant tissue, and
may often be due to irregular tissue development in perielinal chimeras. The
abundance of bud variation with some citrus forms apparently depends upon a
permanent chimeral condition of the types in question.
The selection of bud mutations as a tool in citrus breeding has
yielded some important results. Apogamic seedlings following inter-
specific crossing have given rise to the Davis grapefruit, the Silverhill
satsuma orange, and the Oklawaha sour orange. In this group may be
included the Everglade and Palmetto limes and Weshart and Trimble
tangerines, although the supposed difference in these strains from the
parental varieties has not warranted their continuance as distinct
varieties. Evidence as to the behavior of the Lue orange indicates
that this variety is apparently a nucellar seedling of the Valencia
variety. A group of unnamed navel orange seedlings derived from
seed of the Washington Navel pollinated with trifoliate orange pollen
but showing no hybrid characters offer promise in securing new navel
varieties adapted to Gulf coast conditions. In the same series,
crosses made on the Thomson Navel gave only worthless fruits of the
dry type, while a large percentage of the apogamic seedlings of the
Washington Navel are vigorous growers and produce juicy fruits of
more or less merit. If some of these prove to fruit satisfactorily under
Florida and Gulf coast conditions, a navel variety may be found to
meet the need in this section.
The work of Shamel and his coworkers in bud selection has preserved
the original strains of commercial varieties and also yielded some
superior new ones, as already detailed.
Chace, Church, and Denny (8, 9) studied the inheritance of fruit
composition in 18 mutant strains of Washington Navel orange and
several mutant strains of Eureka and Lisbon lemons isolated by
Shamel, Scott, Pomeroy, and Dyer (63, 64). Chace and coworkers
concluded that differences in the chemical composition of fruit exist
between mutant strains, and that these are heritable. In Washington
Navel strains some of these differences were closely connected with
physical differences and others not. The differences generally found
were in quantities of peel, oil, insoluble solids, and acids. Less varia-
tion was found in the specific gravity of the fruits and in the soluble
solids and sugars of the juice. Strains of fruit with smooth skin were
found to contain only small quantities of oil. In the Lisbon lemon
mutants significant differences were found in specific gravity of fruit,
proportion of rind, and percentage of acids; and in the Eureka lemon,
in percentage of acids.
Haskins and Moore (27) observed premature flowering, albinism,
fasciation, twisting, and peloric leaf formation in citrus seedlings grown
from X-rayed seeds.
Selection within self-fertilized lines as a tool has little or no value
in citrus breeding on account of polyembryony in most citrus types.
The experience of Frost (20) at the Citrus Experiment Station has
CITRUS FRUITS 797
shown that there is great loss of vigor and fertility with selling.
Toxopeus (74) and others have shown that the pummelo has no
nucellar embryony and is usually self -pollinated. The progeny are
usually quite uniform, and in such cases it is possible to develop more
highly homozygous races by selection within self -fertilized lines.
Hybridization as a means toward the improvement of citrus varieties
was undertaken by the Department in 1892 and has been continued
ever since, and the progenies produced are being extensively tested in
cooperation with the California, Florida, Texas, and Alabama experi-
ment stations and many citrus growers (70, 71, 84, 86). Some
concrete results of definite value have been achieved as a result of
this cooperation, as detailed under the improvement of citrus varieties
above. Frost, in California, has carried on valuable work in this field
since 1914, which has recently yielded promising citrus varieties.
The work in Florida carried on by Camp and Jefferies, in Alabama by
Yates, and in Texas by Yarnell and Wood was begun quite recently,
and not enough time has elapsed to yield any definite results.
United Status Department of Agriculture
Breeding Results
Breeding work by the Department was initiated by Webber and
Swingle and is carried out on the cooperative testing basis with the agri-
cultural experiment stations and citrus growers in the subtropical fruit
regions. The major part of the work is concerned with interspecific
hybrids in which (1) the mandarin orange type is crossed with other
citrus types with the object of securing high color of rind and flesh and
also the "bouquet" of the tangerine in hybrid forms; (2) the lemon and
lime are crossed with each, other and with other citrus types; (3) bige-
neric crosses of the trifoliate orange are made with species in other
genera, primarily to increase the hardiness of the off spring; and (4)
various crosses are made to explore the possibilities in other directions.
The practical results from this work have been, previously considered
in the text and are summarized in table 7 of the appendix.
Mandarin Crossed With Other Citrus
Among the interspecific crosses that have given the most interesting
results is the cross of the mandarin orange species on the grapefruit.
In no case were hybrids produced when grapefruit pollen was trans-
ferred to the mandarin orange stigma, but the reverse operation has
yielded abundant results.
The first crosses of this nature were made by Swingle in 1897 and
by Webber in 1898. Webber and Swingle found wide variation in
the Fi progeny. Out of the first crosses two varieties were introduced ,
as already indicated, but in these the susceptibility to scab of the
grapefruit parent was apparently dominant, and in addition the fruits
were of siich character that the keeping and shipping quality was
unsatisfactory.
During the period 1908-12 Swingle, E._M. Savage, and F. W. Savage
made a second series of crosses of a similar nature. The results were
similar to those already stated, except that a number of the progeny
were highly resistant to citrus scab and also possessed good shipping
quality. An attempt was made to proceed a step farther through
798 YEARBOOK, 1937
selection from segregating seedlings in the F2 generation, but on
account of excessive nucellar embryony only one seminal seedling of
merit was secured, which gave rise to a tangelo variety of promise, the
San Jacinto. This was introduced in 1931.
A further attempt was made to secure desirable types by backcross-
ing the tangelo on the grapefruit, and in this case a fair number of
seminal offspring were secured. In growth habit these resembled the
pollen parent, the Sampson tangelo, but they were less vigorous. The
fruit of two such backcrosses proved to be small, round, pink-fleshed,
of low acidity and high sugar content, characters not present in either
parent. One variety of the pink-fleshed backcross has been intro-
duced as the Wekiwa.
Crosses made between the satsuma orange and the sweet orange
have given rise to types somewhat similar to those secured by the
tangerine-grapefruit cross with the flesh color and shape of the sat-
suma and the tight rind and size of the sweet orange (Ruby), but with
high acidity and late maturity not found in either parent.
The third series of grapefruit-tangerine crosses were made by Traub,
Robinson, and Savage, 1934-36, with the object of producing 'seed-
less" tangelos._ Marsh and its mutation, Thompson, and Davis, all
"seedless" varieties, were used in place of Bowen, a seedy variety,
which was chiefly utilized in previous crosses. These so-called "seed-
less" varieties are highly self-sterile and intersterile -and produce few
or no seeds even in mixed plantings.
Crosses between the tangerine and the sweet orange generally gave
types similar to the latter but of small size.
Lemon-Lime Crosses
Among crosses between the lime and the lemon, the Perrine lemon, a
promising variety, was found to be immune to citrus scab and lime
withertip. It has already been mentioned and will be discussed more
fully under disease resistance later.
Trifoliate Orange Crossed With Citrus and Fortunella Species
Citrus hybrids involving trifoliate orange (Poncirus trijoliata) as
one parent have given rise to interesting results. The crosses were
made by Swingle and Webber beginning in 1893 and at several times
subsequently. In the first series 212 crosses were made and 13
hybrids (citranges, i. e., trifoliate X sweet orange) were secured.
Most of these had the trifoliate orange as the seed parent, but in one
case (Rusk citrange) the sweet orange produced the seed. There was
wide variation in the characters of the hybrids. In most cases the
leaves were of the trifoliate type, but unifoliate types were also
secured. All were evergreen in habit; in fruit character there was also
great variation in size, color, etc. In all cases the rind oil character
was inherited from the trifoliate parent, and in most cases the juice
character was intermediate. In none of the fruits was the juice
character sufficiently like that of the sweet orange to give these fruits
any prospect of commercial usefulness. Most of the progeny pro-
duced only nucellar embryos when an attempt was made to secure an
F2 generation by self-pollination, except in the case of the Sanford and
Phelps citranges, which showed hybrids with segregation for leaf
CITRUS FRUITS 799
characters. Seedlings of those segregating varieties were distributed
for trial but thus far have produced nothing of special merit.
Hybrids were later secured by crossing the citrange and the kumquat.
As a result the objectionable oil content of the fruit was reduced and
an acid fruit type secured which has been called the citrangequat.
One of the progeny, the Thomasville, shows high resistance to citrus
canker, which was inherited apparently from the kumquat ancestor.
The citrange crossed with calamondin has given an acid fruit type in
which the disagreeable oil is eliminated. It has been called the Glen
citrangedin. This type is relatively frost-resistant. Attempts made
to secure the F2 generation have boon unsuccessful, since only nucellar
embryos were secured. „ , „. ^
J inner Citrus Crosses
The lime crossed with the kumquat has given rise to small acid-
fruited progeny which are immune to lime wither tip and decidedly more
frost-resistant than the true limes.
Various other crosses were made involving pummelo, sour orange,
and other citrus species. The most interesting is the cross between
the Eustis limequat, with a haploid chromosome number of 9, and
the Hong Kong kumquat (Fortunella hindsii), with a haploid chromo-
some number of 18. This has given rise to a triploid hybrid, as
reported by Longley, resembling the PTong Kong kumquat but larger
and of greater vigor. It is of potential value in further crossing to
secure seedless kumquat types, since many triploids are self -sterile and
intersterile.
Inheritance in Citrus and Related Species
A number of hypotheses have been advanced to explain the wide
variation in the progeny secured in the h\ generation citrus crosses.
Webber (84) in 1905 suggested that there must be some influence,
either direct or indirect, of male parent on nucellar embryos, that the
male element imparts the tendency to the segregation of characters
that exist in the mother parent— characters that as a rule are probably
of very mixed origin — but does not transmit any characters of the male
parent. The Mendelian principles of unit factors, dominance, and
segregation seemed inadequate to Swingle to account for his observa-
tions, and in 1913 he proposed the hypothesis of zygotaxis (67).
Swingle defined his hypothesis of zygotaxis as —
the arrangement in syngamete (zygote) of the chromatin and other hereditary
substances derived from the parental gametes and the persistence of this arrange-
ment in the cells produced by the subdivision of the syngamete.
In further explanation of his hypothesis he states:
It is assumed that the particular zygotactic arrangement taken up by the
chromosomes of the parental gametes usually persists with little or no change
throughout the life of the organism * * *. The fundamental idea underlying
the term zygotaxis is that the architecture of the zygote with reference to its idio-
plastic particles, as well as its mechanisms for transmitting hereditary tendencies
into expression, is determined to some extent at the moment of fusion of the two
parental gametes and that this arrangement of parts is transmitted to the cells of
the organism to which the zygote gives rise.
The hypothesis of zygotaxis was vigorously opposed by Hagedoorn
and Hagedoorn (2fi) and by White (89). The former workers sug-
800 YEARBOOK, 1937
gested that variable Fi progeny in citrus crosses apparently are due
to habitual self-sterility and the sexual production of seeds. White
points out that the F, variation in citrus hybrids, in the light of the
data at hand, apparently results from differences in the gametic com-
position of the heterozygous parents.
Frost (20) sums up the evidence for and -against the theory of
zygotaxis and states that —
enough is known of the production of new characters by new combinations of
genes in crossing to warn us against setting any narrow limits to the probable
results of recombinations in crosses between two highly heterozygous species.
* * * It is concluded, from the available evidence, that citrus forms are in
general extremely heterozygous. * * * This conception seems highly sig-
nificant. * * * In the evolution of heterozygosis, polyembryony probably
was an important factor.
Frost suggested that lethal and sublethal effects in selfing and
crossing may be the result of homozygosis of inevitably unfavorable
genes and may also be in part a result of incompatible recombinations.
Heterosis, however, according to Frost, is probably more often
secured in crossing.
Inheritance of Disease Resistance
The various citrus types and varieties show great variation in
inheritance of resistance or susceptibility to various diseases. The
summary given in table 3 is based largely on the text by Fawcett (15).
Winston, Bowman, and Bach (90) studied the resistance of citrus
types and varieties to sour orange scab, Sphaceloma jawcetti, and
found the following not susceptible: Kumquat; citron; Kansu orange
(Citrus junos Tan.); Mexican, Woglum, and Tahiti limes; Koyal and
Triumph grapefruit; Cuban shaddock; Bergamot orange; most sweet
oranges; and Cleopatra mandarin. The work of Peltier and Fred-
erich (52) has shown that citrus scab cannot survive under California
conditions, indicating that susceptibility under certain conditions
may not be apparent.
Fulton (22) made a study of the susceptibility of citrus types and
varieties to Key lime withertip or anthracnose (Gloeosporium limeiti-
colum). He found that the West Indian (Key) lime and the Domini-
can (thornless) lime are highly susceptible. Other lime varieties
have not given undoubted evidence of susceptibility. Hybrid West
Indian limes, sweet orange, grapefruit, lemon, Citrus nobilis, and others
have proved immune. Since only two types are highly susceptible,
it is suggested that other closely related . varieties might be substi-
tuted in culture. It is interesting to note that susceptibility seems
not to be a dominant factor in Fx hybrids.
Peltier and Frederich (51) made extensive studies of the suscepti-
bility of Citrus and related genera to citrus canker (Pseudomonas
citri) under greenhouse and Gulf coast conditions. Lee (4-1, J+2)
made similar studies in the Orient. Although there is no immediate
need for varieties and stocks resistant to citrus canker, since the
epidemic in the upper Gulf coast and in Florida has been practically,
eradicated since 1925, it is of advantage to select resistant types where
possible as an insurance in case the disease should be inadvertently
reintroduced. Grouped in order of susceptibility, varieties of grape-
fruit and pummelo (shaddock) proved extremely susceptible (except
two pummelo varieties, Hirado and Siam, and the Triumph grape-
Table 3. — Relative susceptibility of citrus species and varieties and related species to principal diseases
[++ indicates high, + medium, and ± slight susceptibility, — indicates high degree of immunity or practically complete immunity]
Species or variety
Mai di
gomma
(foot
rot)
Brown
rot
gum-
mosis '
Psorosis
Bark
rot of
Orient
Decor-
ticosis
Mela-
nose
Sour
orange
scab
++
++
++
=fc
++
+
+
+
+
++
±
+
Sweet
orange
scab
Austra-
lian
citrus
scab
Canker
Blast
Citrus
anthrac-
nose*
Key
lime
anthrac-
nose
Black
spot
(Pho-
ma)
Phyllo-
sticta
leaf
drop of
Orient
Lepro-
sis
(nail-
head
rust)
Mai
secco
Sweet orange (Citrus sinensis)
Sour orange (C. aurantivm). ___ __
++
++
+
++
++
+
+
+
+
+
++
++
±
++
++
++
+
+
+
++
++
++
+
+
+
++
+
+
+
+
+
-
++
++
±
dz
+
++
+
++
—
Lime (C. aurantifolia):
++
+
±
++
++
+
±
±
d=
++
++
-
++
+
+
+
++
+
+
-
+
++
++
+
+
+
+
+
±
++
+
+
-
-
+
+
+
+
+
+
+
+
Tangerine (C. nobilis var. deliciosa)^
Satsuma (C. nobilis var. unshiu)-.-
+
+
+
++
++
++
-
+
+
+
+
+
dz
±
+
+
++
dz
' -
—
Trifoliate orange (Poncirus trifo-
+
Eremocitrus glauca (Lindl.) Swin-
—
Chaetospermum glutinosa (Blanco)
j
1
1
-a
So
c:
Co
•*!
So
CI
1-1
CO
1 Some pummelo varieties resist brown rot gummosis; others are very susceptible.
1 Anthracnose of citrus other than Key lime.
03
O
802 YEARBOOK, 1937
fruit). Lemon varieties and the trifoliate orange (Poncirus trifoliata)
are only slightly less susceptible than grapefruit. Classed as moder-
ately susceptible are the sweet oranges, sour oranges, citrons, and
limes, except that the Tahiti lime is much less susceptible than the
Mexican lime. The mandarin group (Citrus nobilis varieties) as
a whole is only slightly attacked, as is also the calamondin. The
outstanding resistant members of the edible citrus fruit group proved
to be the kumquats (Fortunella spp.), except the susceptible Hong
Kong kumquat (F. hindsii), resistance in kumquats amounting to
practical immunity under field conditions.
The extensive citrus canker tests made by Peltier and Frederich
(SI) afforded opportunities for testing the numerous hybrids devel-
oped by the Department,- these hybrids involving reciprocal crosses
between numerous species and varieties ranging in their reaction to
canker infection from extremely susceptible to very resistant. The
results of these tests may be briefly summarized as follows. All the
trifoliate orange first crosses proved quite susceptible to canker,
like the parent, Poncirus trifoliata. In the second cross, that is,
citranges crossed with other parents, those hybrids with the man-
darin orange or the kumquat as one parent proved decidedly resistant;
in fact, the citrangequat (Thomasville variety) proved practically
imnmne, fully as much so as the kumquat. Likewise the limequat
and the orangequat can be regarded as similar to the satsuma in
resistance. The calamondin, while somewhat resistant itself, does
not carry this resistance into the hybrid, with one exception, the
citrangedin (citrange X calamondin). Most of the grapefruit
hybrids have proved quite susceptible, although certain of the tanger-
ine and satsuma crosses with grapefruit (tangelos) show enough
canker resistance to place them beside the mandarin oranges in their
resistance to canker. Peltier and Frederich conclude: "In the search
for promising canker-resistant plants the results of over 4 years'
investigations seem to point to the fact that our best plants will come
from the hybrids."
Gummosis, a disease caused by Phytophthora citrophthora, has been
studied by Klotz and Fawcett (87), who tested 78 species and varieties
for resistance. The sour oranges proved very resistant, while the
lemons were most susceptible. Klotz (86) has shown that the resist-
ance apparently is due to some cellular product of the host that has
an inhibiting action on the fungoid enzymes.
Toxopeus (75) reported that the factor or factors for resistance to
foot rot (Phytophthora parasitica) might possibly be recessive, and in
that case he suggests that selection for individuals resistant to this
disease be made in the second generation (F2) after crossing
Inheritance of Capacity to Produce Vitamins
Preliminary tests have been made indicating how capacity to pro-
duce vitamins is transmitted in citrus hybrids. The only published
report (71) has to do with tests made in 1928 with the Sampson
and Thornton tangelos, comparing the vitamin B content of these
hybrids with that of the parental varieties, grapefuit and tangerine.
These tests, made by the Bureau of Chemistry and Soils of the
Department, were summarized as follows:
CITRUS FRUITS 803
Both charts are in agreement in showing tangerine juice to be a better source
of vitamin B than the juice of the other fruits fed, and also that tangelo juice is
approximately equal in vitamin B potency to grapefruit juice. Therefore, with
respect to vitamin B production the tangelo has inherited the characteristics of
the grapefruit (71 , footnote, p. S) .
With respect to vitamin C, which is of still more importance in
the citrus fruits, tests are in progress and some indications as to
inheritance have already been secured. These preliminary tests (IS)
were made during the 1935-36 season by Esther P. Daniel, Bureau
of Home Economics, in cooperation with Traub and Robinson,
Bureau of Plant Industry, of the Department. In these tests the
ascorbic acid content of fruit samples at maturity was determined
by the titration method. The figures below indicate milligrams of
ascorbic acid per cubuc centimeter of juice:
The Thornton and Orlando tangelos (range 0.33 to 0.35) gave results approxi-
mating those of the Bowcn grapefruit parent (average 0.35); the Sampson,
Minneola, and Seminole (range 0.18 to 0.28) proved more like the Dancy tangerine
parent (average 0.24). One variety that was grouped with the tangelos, the
Umatilla, but that in fact is a hybrid between satsuma and Ruby oranges, gave
a much higher content of ascorbic acid (0.40) than the true tangelos. The
Clement tangelo, which has the Clementine as the pollen parent, had the highest
content (0.64). The Clementine is reputed to be a natural hybrid between the
sour orange and the tangerine and has a higher content of ascorbic acid (0.37)
than the Dancy (0.24).
The Perrine lemon — a hybrid of lemon and lime — appears to inherit from the
lemon parent rather than from the lime, having an ascorbic acid content of 0.40
as compared with 0.22 in the lime.
The limequat (Lakeland) ranks low (0.17), like the lime parent. It is interest-
ing to note that the sweet lime (often called sweet lemon) has a fairly high ascorbic
acid content (0.33), despite its almost complete lack of citric acid. Apparently
there is no positive correlation between citric and ascorbic acid content.
Results at State Stations
California
The hybridization work at the Citrus Experiment Station at River-
side was begun by Frost (17) in 1914, and since that date pollinations
were made mainly in 1915, 1916, 1928, 1929, and 1931. More work
of this nature is planned for the next 2 or 3 years. The work consists
of selfing and crossing and the study of genetic variation in nucellar
seedlings.
In general the work is confined to crosses between species and
within the mandarin orange group, Citrus nobUis. In all cases selfing
of the parents is carried along as far as practicable with the work of
crossing. In all, six varieties of sweet orange, three of grapefruit,
and four of lemon have been used in crossing. Within the mandarin
group four varieties were used in crosses. The chief results so far
have been secured by selection within the first generation (Fj), but
promising F! hybrids have been selfed, and crosses have been made
between promising hybrids and standard varieties.
The Fi hybrid combinations represented by at least one individual
include the following: Lemon and mandarin (tangemon), mandarin
and mandarin (of distinct botanical varieties), orange and mandarin
(tangor), grapefruit and mandarin (tangelo), grapefruit and orange
(orangelo), lemon and orange (oramon), and grapefruit and lemon
(lemelo). The most promising hybrids not yet introduced seem to
804 YEARBOOK, 193 7
be the following: One each from King mandarin X Dancy tangerine
(fruit of very good size, fair shape, and very good flavor); from
Mediterranean Sweet orange X Dancy tangerine (very good fruit
color and flavor, extra early); and from satsuma (Owari) X Lisbon
lemon (fruit rough, very juicy, seedless, high in acid, excellent in
aroma) .
The most promising results have been secured by crossing within
the mandarin group. Three varieties already mentioned have been
introduced, and at least two or three more are under consideration
as candidates for introduction. The earliest work at the Citrus
Experiment Station led to the use of the King mandarin as the main
seed parent in these crosses.
During the last few years certain hybrids from crosses of lemons
with grapefruit and of "hedge bergamot" with grapefruit have been
studied as possible stock types for lemons. On the basis of tree
characters, seed production, and resistance to inoculated phytophthora
gummosis, several hybrids have been selected for further trial, and
a preliminary study of seedlings has been made. At present one
hybrid from Imperial grapefruit X hedge bergamot and one from
Eureka lemon X Imperial grapefruit seem most promising, although
it is not certain whether they have enough nucellar embryony to
produce adequately uniform seedlings for rootstocks.
A general survey including 3,800 trees is under way in a search
for genetic differences from the seed parent. Tetraploids are listed
and studied, and a special study is being made of a few other progenies
showing unquestionably variant characters (dry fruit from one
parent tree, nonnavel fruit and pollen production from two navel
parent trees without pollen, late-ripening fruit from one parent
tree). A study of possible genetic differences in fruit shape (satsuma)
and pulp color (blood orange) among progeny of the same seed-parent
tree has also been undertaken.
The related specialized studies carried on by Frost include:
(1) Polyembryony. — Counts of total embryos and counts of generative and
nucellar seedlings have been made for horticultural varieties, tetraploid and dip-
loid nucellar progeny, and Fi hybrids. Among about 1,200 hybrids, 10 cases of
duplicate hybrids (two identical hybrids from one seed) have been found, ob-
viously the result of embryonic fission. Nucellar embryos seem to be somewhat
less abundant with tetraploids than with corresponding diploids.
(2) Triploidy and tetraploidy. — About 2 percent of about 3,800 nucellar seed-
lings were tetraploid and have been especially studied. These are of no horti-
cultural value. A few hybrids have recently been produced by crossing a tetra-
ploid with diploids as pollen parents; the reverse combination failed to produce
seed. About V/z percent of about 1,200 hybrids have been proved to be triploid,
none tetraploid; several times as manv are suggestive of triploidy, but their
chromosome constitution has not been determined.
(3) Chromosome behavior. — Preliminary studies have been made on chromo-
some conjugation and segregation in diploids, triploids, and tetraploids, and on
irregularities at the microsporad stage.
(4) Clonal senescence. — Studies are in progress on various juvenile characters
of young seedlings and clones, especially thorniness, scarcity of flowers, and general
vigor of growth, and on their decline with increasing age from seed and increasing
length of shoot growth.
(5) Chimeras and bud variation. — Studies of tree and fruit characters have
been made on forms that seem to be chimeral, in the general variety collection
of citrus.
CITRUS FRUITS 805
Florida
The citrus hybridization work by Camp and Jefferies at the Florida
State Citrus Experiment Station, Lake Alfred, with acid citrus fruits
was begun in 1924. Numerous crosses have been made, including 18
different combinations, with the following as parents: Calamondin;
Rangpur lime; Meyer, Genoa, and Villa Franca lemons; Jamaica and
Key limes; and the limequat. The Ft progency have reached the
fruiting stage and are under test.
The work carried on in cooperation with the Department is^ con-
cerned with bud selection and with the testing of the citrus varieties
originated by the Department.
The citrus progeny testing collection, begun in 1921, contains 52
strains of oranges, tangelos, grapefruit, and tangerines selected from
record trees, and these have been intensively studied. From the
superior strains budwood has been distributed in quantity to nursery-
men. Selections from Thompson and Marsh grapefruit and Valencia,
Hamlin, Parson Brown, Temple, and Pineapple oranges are in
greatest demand.
The Department hybrids have been tested out over a long period.
According to the latest report, the utilization of Rusk and Morton
citranges as rootstocks for the satsuma orange is promising.
Alabama
The citrus work of the Alabama Agricultural Experiment Station,
begun in 1933 in cooperation with the Department, is concerned with
the testing out of over 50 strains of the satsuma orange, both early-
and late-maturing, and with the selection in the F2 generation of cit-
range, particularly for high quality fruit and cold resistance. The
experiments have not been carried on for a sufficient period to yield
concrete results, although several of the recently introduced satsuma
orange strains appear promising for hardiness, early bearing, and
fruit quality. * T<guu
The citrus breeding work begun by Yarnell and Wood at the Texas
Agricultural Experiment Station in 1934 comprises a study of the
adaptability of citrus varieties and citrus relatives, both for fruit and
rootstock purposes; mass selection of open-pollinated citrange seed-
lings, primarily for cold resistance; crossing and selfing in sweet
orange, mandarin orange, grapefruit, and acid citrus fruits. In all
cases of crossing and selfing some cytological studies of root tips,
buds, and young fruits are also carried along.
The following rootstock plants introduced primarily by the Depart-
ment are under test: (1) Balsamocitrus paniculata Swingle; (2) citradia;
(3) Citrus aurantifolia — Key, Mexican, Rangpur, Tahiti; (4) C.
aurantium — African, Bittersweet, Brazilian, Paraguay, Roubidoux,
Rough Seville, standard Sour; (5) C. bergamia Risso; (6) C. ichangen-
sis; (7) C. grandis — Triumph; (8) C. limetta Risso — sweet lime; (9)
C. limonia — Keller, Meyer, Perrine, Ponderosa, Rickart, Rough; (10)
C. maxima Marr. — Chinese pummelo, Cuban and Pink shaddocks;
(11) C. medica — Diamante, Etrog, Indian, Italian; (12) C. mitis —
calamondin; (13) C. nobilis — Cleopatra; (14) C. sinensis — Oroville,
806 YEARBOOK, 1937
Weldon, Raymondville ; (15) citrange; (16) citrangedin — Glen; (17)
citrangequat — Thomasville; (18) citrumelo (citrange X pummelo);
(19) limequat — Lakeland, Tavares; (20) Suen Kat orange; (21)
tangelo — Altoona, Clement, Lake, Minneola, Sampson, Seminole,
Thornton, Umatilla, Wekiwa, Yalaha.
The following crosses have been made: (1) Sweet orange — Rubj- X
Hamlin, Valencia X Hamlin, Ruby X Meyer lemon and reciprocal,
Parson Brown X Meyer lemon and reciprocal, Parson Brown X
Ponderosa lemon, Pineapple X Pink Marsh grapefruit, Valencia X
citron; (2) mandarin orange and hybrids — Meyer lemon X Clementine
tangerine, Meyer lemon X Owan satsuma, Owari X Hamlin orange,
Owari X Pink Marsh grapefruit, Thornton X Clementine, Thornton
X Pink Marsh; (3) grapefruit — Meyer lemon X Pink Marsh, Pine-
apple orange X Pink Marsh, satsuma orange X Pink Marsh, Thornton
tangelo X Pink Marsh; (4) acid citrus fruits — Meyer lemon X Pink
Marsh grapefruit, Meyer lemon X Mexican lime, Meyer lemon X
Clementine tangerine, Meyer lemon X Eureka lemon, Meyer lemon
X citron, Meyer lemon X Ruby orange, Meyer lemon X satsuma
orange, Meyer lemon selfed, Parson Brown orange X Meyer lemon,
Parson Brown orange X Ponderosa lemon.
The citrus varieties originated by the Department, and also intro-
ductions from abroad, have been tested out on a cooperative basis
since 1930. The most promising variety in the testing collection at
the Texas substation at Weslaco up to the present time is the Texas
Navel, to which reference has already been made. In cooperation
with the Department more than 50 strains of the satsuma orange, both
early and late maturing, are under test at Texas substations at Angle-
ton and Winter Haven, and attempts to select desirable individuals
of high quality and resistant to low temperatures in second generation
citrange progeny are under way at College Station.
Hawaii
The Hawaii Agricultural Experiment Station (28) reports that
rootstock and variety tests are in progress to determine the suitability
of various combinations of scion and rootstock to different sites and
soils. Many recent introductions of promise are being tested in
comparison with the older standard varieties.
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APPENDIX
United States Subtropical and Tropical Fruit-Breeding Stations
and Early and Present Workers
[An asterisk (*) designates workers all or part of whose salaries were or arc paid from Federal funds]
(1) United States Department of Agriculture, Washington, D. C:
Earlv workers— *H. J. Webber, *W. T. Swingle, *Eugene May, *Frank W.
Savage, *R. E. Caryl, *L. B. Scott,
Present workers — *Hamilton P. Traub, senior horticulturist; *T. Ralph
Robinson, senior physiologist; *Edward M. Savage, assistant plant
breeder; *A. D. Shamel, principal physiologist; *C. S. Pomcroy, associate
pomologist; *A. E. Longley, associate botanist.
(2) Alabama Agricultural Experiment Station of the Alabama Polytechnic
Institute, Gulf Coast Substation, Fairhope:
Present workers — *Harold F. Yates, acting superintendent.
(3) Arizona College of Agriculture and the Agricultural Experiment Station,
Tucson:
Present workers — -W. E. Bryan, head of Department of Plant Breeding (date
breeding) .
(4) California College of Agriculture and the Agricultural Experiment Station
of the University of California:
Early workers— C. S. Milliken, C. L. Dyer, F. N. Harmon.
Present workers — H. J. Webber, emeritus professor of subtropical horti-
culture, Riverside; Ira J. Condit, associate professor of subtropical horti-
culture, Riverside; L. D. Batchelor, director of Citrus Experiment Sta-
tion, Riverside; Robert W. Hodgson, head of Division of Subtropical
Horticulture, Los Angeles; R. E. Caryl, associate in orchard management,
Riverside; H. B. Frost, associate plant breeder, Riverside.
(5) College of Agriculture and Agricultural Experiment Station of the University
of Florida:
Early workers — H. H. Hume, John Belling.
Present workers — H. S. Wolfe, horticulturist in charge, Subtropical Experi-
ment Station, Homestead; A. F. Camp, horticulturist in charge, Citrus
Experiment Station, Lake Alfred; J. H. Jefferies, superintendent, Citrus
Experiment Station, Lake Alfred.
(6) Glen St. Mary Nurseries Co., Glen St. Mary, Fla.:
Early workers — G. L. Tabcr (trifoliate rootstock investigations), H. Harold
Hume (persimmon investigations).
(7) University of Hawaii and the Hawaii Agricultural Experiment Station:
Early workers— *J. E. Higgins, *V. S. Holt, *J. M. Westgate.
Present workers — *J. H. Beaumont, principal horticulturist; *W. T. Pope,
senior horticulturist; *R. H. Moltzan, principal scientific aide; *J. C.
Thompson, principal scientific aide; *W. B. Storey, junior biological
aide.
812 YEARBOOK, 1937
(8) Louisiana State University and Agricultural and Mechanical College and the
Agricultural Experiment Station:
Present worker — J. C. Miller, horticulturist in charge of research.
(9) Puerto Rico Agricultural Experiment Station, Rio Piedras, Puerto Rico:
Early worker — O. W. Barrett.
Present worker — Julio S. Simons, agronomist for plant introduction and
propagation.
(10) Federal Experiment Station, Mavaguez, Puerto Rico:
Early workers — *0. W. Barrett, *Holger Johansen, *T. B. McClelland.
Present worker — *C. L. Home, associate horticulturist.
(11) Panama Canal Zone Experiment Gardens, Summit:
Present workers — *J. E. Higgins, consultant in plant introduction and
utilization; *Walter R. Lindsay, acting director.
(12) Commonwealth of the Philippines, Department of Agriculture and Com-
merce (citrus, avocado, pineapple, and papaya breeding):
(a) Bureau of Plant Industry, Manila:
Early workers— C. F. Baker, T. P. Reyes, P. J. Wester.
Present workers — J. P. Torres, J. de Leon, F. Galang, E. K. Morada.
(b) College of Agriculture, University of the Philippines, Department of
of Agronomy, Laguna:
Present workers — N. B. Mendiola, plant breeder and geneticist; J. M.
Capinpin, plant breeder and cytologist; T. Mercado, assistant plant
breeder.
(13) Texas Agricultural Experiment Station:
Present workers — S. H. Yarnell, chief, Division of Horticulture, College
Station; J. F. Wood, horticulturist, Weslaco; H. M. Reed, horticulturist,
Angleton.
Subtropical and Tropical Fruit-Breeding Stations in Foreign
Countries and Workers and Present Work
Europe and North Africa
Spain:
(1) Estacion Naranjera de Levante, Burjasot, Valencia (citrus breeding):
Present worker — Manuel Herrero.
Italy:
(2) Regia Stazione Sperimentale de Olivicoltura ed Oleiricio, Pescara (olive
breeding) :
Present worker — Julio Savastano.
(3) Regia Stazione Sperimentale di Frutticoltura e de Agrumicoltura, Arcieale
Catania, Sicily (breeding for resistance to mal secco in lemons).
French Morocco:
(4) Experimentation Fruitiere et MaraichSre, Rabat (citrus breeding):
Present workers — F. Lacarello, Director; Ch. Miedzyrzecki, geneticist.
Greece:
(5) Hellenic Kingdom Superior School of Agriculture, Laboratory of Horticul-
ture, Athens (olive and fig variety studies):
Present worker — P. Th. Anagnostopolous.
Asia and Malaya
Palestine:
(6) Jewish Agency, Agricultural Experiment Station, Rehoboth (citrus breeding):
Early worker — J. D. Oppenheim.
Present worker — Ch. Oppenheimer.
(7) Agricultural School, Mikweh-Israel (collection of Jaffa orange bud mutations) :
Present worker — S. Yedidja.
India:
(8) Poona, Bombay Presidency; Horticultural Section (1) Ganeshkhind Fruit
Experiment Station, Kirkee; (2) Modibag (Garden) , College of Agriculture,
Poona. (Improvement of citrus, mango, papaya, pineapple, guava, pome-
granate, fig, banana, jujube, annona.)
Early workers— W. Burns, S. H. Prayag, L. B. Kulkarni, H. P. Paranjpe.
Present workers — G. S. Cheema, horticulturist and professor of horticulture;
P. G. Dani, assistant; S. R. Gandhi, assistant; S. S. Bhat, assistant;
B. Nazareth, assistant.
CITRUS FRUITS 813
(9) Department of Agriculture, Bihar (mango and papaya breeding):
Present workers — R. Zarbakht-Kahn, horticulturist; It. Shah, assistant;
S. Prashad, assistant.
(10) Royal Agricultural and Horticultural Society of India, Alipur, Calcutta
(variety studies of tropical fruits) :
Piesent worker — Sydney Percy Lancaster.
(11) Government Gardens, Saharanpur, United Provinces (lime, mango, and
loquat improvement) :
R. D. Fordham, deputy director.
Straits Settlements and Federated Malay States:
(12) Department of Agriculture, Kuala Lampur (pineapple breeding):
Present worker — W. D. P. Olds, director of agriculture.
Siam:
(13) Department of Agriculture and Fisheries, Bangkok (variety studies of
tropical fruits) :
Present worker — Luang Suwan, director general.
China:
(14) College of Agriculture, Lingnan I.'nivorsity, Canton; Department of Horti-
culture (variety studies of citrus, avocado, mango, papaya, pineapple, ba-
nana, lychee, "diospyros, annona, artocarpus, Chinese olive (Canaria) ,
etc.) :
Present workers — G. Weidman Groff, professor of horticulture; Pui-man
Lei, Iu-nin Shiu, A. N Benemerito.
Japan:
(15) Imperial Horticultural Experiment Station, Okitsu (fig, loquat, and citrus
breeding) :
Present worker — T. Tanikawa, acting director.
(16) Chiba Horticultural College, near Tokyo (loquat variety studies):
Present worker — Tarji Miki, professor of pomology.
(17) Shizuoka Agricultural Experiment Station (bud mutations of satsuma
orange):
Present worker — Kimijiro Noro, pomologist.
(18) Taihoku Imperial University, Formosa (citrus breeding):
Present worker — Tyozaburo Tanaka, professor of citriculture.
(19) Agricultural Experiment Station, Shirin, Taihoku, Taiwan (subtropical
fruit crops breeding):
Present worker — Y. Sakurai, pomologist.
Netherland East Indies:
(20) Buitenzorg Botanical Gardens (improvement of citrus and other tropical
fruits) :
Present workers — G. J. A. Lirra, horticultural adviser; H. J. Toxopeus,
geneticist.
South and Central Africa
Union of South Africa:
(21) Division of Plant Industry, Union of South Africa; Subtropical Horticultural
Research Station, Nelspruit, Eastern Transvaal (papaya and pineapple breed- .
ing):
Present worker — J. D. J. Hofmeyr, research horticulturist.
(22) Department of Pomology, University of Stellenbosch (fig and olive variety
trials) :
Present worker — O. S. H. Reinecke, head of department of pomology.
Southern Rhodesia:
(23) Citrus Experimental Station, Mazoe (citrus variety trials):
Present worker — L. A. Lee, horticulturist.
Zanzibar, East Africa:
(24) Department of Agriculture (variety trials — citrus, banana, pineapple,
mango, papaya, lychee, and rambutan) :
Present worker — A. J. Findley, director.
Nigeria: . . ,
(25) Agricultural Department, Ibadan (breeding of pineapple, and variety trials
with citrus, mango, avocado, and papaya) :
Present worker — E. H. G. Smith, agricultural botanist.
814 YEARBOOK, 1937
Australia and New Zealand
Victoria:
(26) Department of Agriculture, Division of Horticulture, Melbourne (bud
selection in citrus) :
Present worker — J. M. Ward, superintendent of horticulture.
New South Wales:
(27) Grafton Experiment Farm and the Hawkesbury Agricultural College
(citrus breeding) .
Queensland:
(28) Department of Agriculture and Stock, Brisbane (improvement of citrus,
avocado, mango, papaya, pineapple, date, olive, grauadilla, persimmon, fig,
loquat, and guava) :
Present worker — (Appointment of research staff in fruit crops now under
consideration).
(29) Queensland Acclimatisation Society, Brisbane (introduction of tropical and
subtropical fruits) :
Present worker — R. Allsopp, overseer.
New Zealand:
(30) Department of Agriculture, Horticulture Division, Wellington (citrus,
avocado, and olive variety trials) :
Present worker — J. A. Campbell, director, Horticulture Division.
(31) Department of Scientific and Industrial Research, Plant Research Bureau,
Mount Albert, Auckland (subtropical fruit variety trials) :
Present worker — Dr. Allen.
. , . Mexico, Central America, and the Antilles
Mexico:
(32) Estacion Experimental:
(a) Acapulco, Guerrero (mango, lime, pineapple, and avocado) .
(b) Oaxaca, Oaxaca (mango, lime, avocado).
(c) Jalapa, Veracruz (papaya, mango, pineapple).
(d) Colima, Colima (lime).
(e) Leon, Guanajuato (avocado).
(f) Queretaro, Queretaro (avocado).
(g) Coalan del Rio, Morelos (papaya) .
(h) Hecelchakan, Campeche (avocado).
Honduras:
(33) Lancetilla Experiment Station (United Fruit Co.), Tela (Extensive tropical
fruit variety trials) :
Present worker — Wilson Popenoe, agricultural director.
British Honduras:
(34) The Agricultural Office, Belize (introduction and testing of citrus varieties):
Present worker — H. P. Smart, agricultural officer.
Costa Rica:
(35) Alan Kelso, Aparto. 246, Punta Arenas. (Private work; tropical fruit crop
introduction and improvement.)
Cuba:
(36) Agricultural Experiment Station, Santiago de las Vegas (variety tests and
. selections of citrus, avocado, mango, banana, and pineapple) :
Early workers — M. Fortun, J. Ajete.
(37) Atkins Institution of the Arnold Arboretum (Harvard University), Cien-
fuegos (breeding of citrus and other tropical fruits) :
Present worker — H. C. Gray, director.
Jamaica:
(38) Department of Agriculture, Hope, Kingston (papaya and banana breeding) :
Present worker — L. N. H. Larter, Government botanist.
Trinidad, British West Indies:
(39) The Imperial College of Tropical Agriculture (banana and other tropical
fruits breeding) :
Present worker — E. E. Cheeseman, professor of botany.
„, .. South America
Chile:
(40) Salvador Izquierdo, Monedo 778, Santiago.
(Private work confined mostly to introduction of new varieties of subtropical
fruits.)
CITRUS FRUITS
815
(41) Institute Agronomico do Estada de Sao Paulo, Genetics Department
(citrus and banana breeding) :
Present worker — C. A. Krug, head of department.
Argentina: , , . ,, , , _T .
(42) Estacion Experimental de Concordia, Mimsteno de Agncultura de la Naoion
Argentina (citrus breeding) :
Present worker — Ruben Bence Pieres, ing. agr. and director oi the station.
Table 4. — Chromosome numbers of Citrus species and varieties and related species
(family Rutaceae) as far as determined up to 1936
[See literature citations IS, 19, IS, t'„ SS, U, 4-1, V, W, 72]
Species or variety
Aeglopsis chevalicri
Triphasia Irifolia --
Triphasialrifolia var. bieatens.
Severinia buxifolia —
MicrocHrusmauslTahs
CUropsis schweinfurth ii
Poncirusirifoliata.
Fotlunella crassifolia
F. margarita
F.japonka
F. hindsii ■--
Citrus medico
C. Hmonm .-.
C. limonia var. bivalent..
C. aurantifotia
C. grandis
C. awrantium.
C. sinensis
C. sinensis var. bivalens..
C. nobilis
C. nobilis var. delichsa.-
C. nobilis var. unshiu.
C. mitis
C". khangensis —
Chro-
mo-
some
num-
ber (n)
Authority and year de-
termined
.Remarks
Longley, 1025..
.-.do
Longley, 1937.
Longley, 1925. .
Longley, 11137.
Longley, 1925.
do
__._do
..-do
...do .
do
do
Frost, 1925....
Longley, 1925.
Frost, 1925.....
Longley, 1925.
....do
Frost, 1925
Determined in 1928.
Do.
Frost, 1925; Longley,
1925; Oppcnheimer and
Fraenkel, 1929.
Frost, 1925
Longley, 1925
Nakamura, 1929.
Longley, 1925....
Undetermined.
Quoted by Oppenheimer (49)
without citation of author.
Undetermined.
Table 5. — Citrus species and varieties introduced by the United States Department of Agriculture
CO
ON
Species
Citrus gramlls.
Do-
Do
C. auTanlium.
C. sinensis (sweet or-
ange).
Common or varietal
name
Sha'ddock.
Pummelo.
Grapefruit .
Sour, Bigaradc, or
Seville orange.
Chinotti
Bergametto (bergamot
orange) .
Washington Navel or
Bahia Navel.
Texas Navel.
Algerian _
Matidja
Zatina
Charnoudi (Shamooti)
Capuchin.
Telde
Native habitat
Southeastern Asn_.
Southeastern Asia,
Malaysia.
Source of introduction
.do
China, southeastern
Asia.
China, southeastern
Asia.
.do.
-do..
.do.
-do..
-do..
Lau Chang, Hang
Chang.
Harvard
.do..
-do..
-do..
-do-
Original habitat; also Aus-
tralia, West Indies,
South Africa.
Siani, China, India, Phil
ippines, Hawaii.
South Africa.
Where now available
Original habitat; also
Spain, North Africa,
West Indies, Australia.
Southern France
Sicily- .
Brazil..
.do-
Algeria
do— ..
....do—-.
Palestine..
Chile
Canary Islands-
China
Cuba
Orlando, Kustis, Coconut
Grove, and Lake Alfred,
Fla., Riverside, Calif., Wes-
laco, Tex.
Eustis, Fla _
-do..
Oiiando, Eustis, Coconut
Grove, and Lake Alfred,
Fla., Riverside, Calif.
.-.do ..
_do-
do-
Weslaco, Tex., Riverside, Calif
Orlando and Eustis, Fla
-..do
do
Orlando, Kustis, and Coconut
Grove, Fla., Riverside,
Calif., Weslaco, Tex.
Orlando, Eustis, and Oneeo,
Fla.
Orlando and Eugtis, Fla
Remarks
Orlando, Coconut Grove, and
Eustis, Fla.
Cuban shaddock is being tested for possible
use as rootstock; Arajan (pink,) Alamoen
The following varieties are being tested for
utilization of fruit and resistance to saline
soil solution: Kao Pan, Kao Phuang,
Thong Dee, Nakorn, Victoria, Siam,
Fandan Wangi, Better Pummelo, Wong
Yau, Banda, Indian Red.
Cecily grapefruit, reputed to be a seedless
mutation, being tested for difference, if any,
from standard seedless varieties.
For testing as semihardy and disease-resistant
stocks for use in hybridization, for utiliza-
tion as marmalade fruits.
A preserving fruit; also useful as a potted
dwarf plant.
Used in preparing flavoring extracts and per-
fumes.
The original introduction which served as a
basis for developing the orange industry of
California. Other varieties, as the Thom-
son Navel, have sprung from this variety.
Not adapted to Florida culture.
Several navel types (seedless) introduced by
Dorsett, Shamel, and Popenoe; one of
which is being propagated in southern
Texas as the Texas Navel for testing and
breeding.
Reputed to be productive and of good qual-
ity; being tested, not yet fruiting.
Do.
Do.
A large seedless orange, famous as the "Jaffa"
orange in European markets; for testing; its
adaptability and for use in hybridization.
Small, hardy orange; useful as potted orna-
mental and in breeding.
Small-fruited sweet orange; reputed of high
quality; for testing and breeding.
Sweet orange reputed to be of high quality;
for testing and breeding; not yet fruiting.
An early-maturing orange, reputed to be of
hybrid origin; for testing.
tee
©
©
C. nobilis var. deltciom
(mandarin group)
C. nobUis var. unsltjtt
(satsuma orange) .
C. medica (citron) .
Tankan.
Rico
Selecta
Byfield seedless.
Ponkan
Clementine.
Snen Knt (sour man-
darin).
Changsha.
Chin Kom
SunChuSha
Hung Kat ...
Beauty (Ellendale)
tangerine
Vermilion tangerine, . .
Kawano (early); also
sbou; 40 similar
early-maturing sat-
suma mutations.
Ikiriki, Suzuki, lliri,
Kashiina, Mizomo-
to, Miyasaki.
Corsican, Spatafora,
Peretto, Java, Dia-
mante, Chinese,
Etrog.
_do_.
_do_
_do.
_do_
China-
China .
-do.
...do..
...do..
...do-
China..
Japan .
do-
India..
_] Formosa
.! Puerto Rico_.
Brazil
Australia.
.do-
China and Taiwan..
Algeria
China
.do.
.do-
-do_.
.do.
Australia_.
China-
Japan...
.do .
Italy, Sicily, Corsica.
Greece.
Orlando and Eustis, Fla.,
Riverside, Calif., AVeslaeo,
Tex.
do
Orlando, Fla
Orlando, Eustis, Coconut
drove, and Oneco, Fla.,
Riverside, Calif.
.—do
.do-
Orlando, Fla., Fairhope, Ala.
Orlando, Fla.
-...do
... .do
do
_do.
Fairhope and Silverhill, Ala.,
Eustis, Fla. (in pari), "Win-
ter Haven, Tex. (in part).
.do-
Orlando, Eustis, Coconut
Grove, and Oneco, Fla.,
Weslaco, Tex., Riverside,
Calif.
A small, disease-resistant, late-maturing
orange of high color. Used for testing and
breeding.
Rico, nos. 1 to 6. Six selections made from
seedling oranges, for seedlessness and qual-
ity; not yet fruiting.
Parent variety of the Washington Navel.
Reputed to be a midseason orange, seedless,
of good quality. Not yet fruiting.
A large, free-peeling orange, early to mid-
season, disease-resistant, highly esteemed
in the Orient; for testing and breeding.
Reputed to be a natural hybrid of tangerine
and sour orange, but resembles tangerine;
use in crosses with grapefruit gave rise to
Clement tangelo.
Serves as budding stock for best mandarin
varieties of China and Formosa; being
tested as stock; for hardiness and disease
resistance.
Very hardy, free-peeling orange; promising
for use in breeding.
Not yet fruiting.
Do.
Do.
To be tested for fruit quality, size, disease
resistance, and hardiness.
Do.
These large-fruited, early-maturing satsuma
varieties make possible earlier shipment of
the commercial crop— avoiding frost risk
and competition with tangerines. Being
tested for stock affinity, hardiness, stability
of type, fruit quality; also used in crass
pollinations.
Satsuma varieties of local fame in Japan,
being tested for possible superiority to
standard variety (Owari) in United States;
for hardiness, fruit quality, size of fruit,
Varieties of citron adapted to the preserving
industry are being tested for productive-
ness, disease resistance, and quality;
hybrids being made to improve existing
forms. Commercial citron growing has
made a start in Florida, Puerto Rico, and
California, but information is needed on
stocks, varieties, disease resistance, etc.
There is a limited demand for the Etrog
variety, used in certain Jewish ceremonials;
its form must accord with a fixed standard.
C-5
is
-=1
in
oo
Table 5. — Citrus species and varieties introduced by the United Slates Department of Agriculture — Continued
CO
I— '
co
C. limonia (lemon).
C. uuraiitifoliu (limo)__
C. milk..
C khangensis..
C.junos Sieb._
C.hyslrix
Common or varietal
name
India, Simla, Mazuo
(wild types).
Algiers (seedless)
Meyer
Sumatra -
Woglum.
Riant, Cameron,
Debe, Dominica.
Sweet-
Java
Calamondin.
Yuzu-
Kalpi.
Native habitat
India,
Asia.
.do..
southeastern
Chiua-
Sumatra
India, Malaysia,
southeastern Asia.
— .do
....do
— do
Philippine Islands. . .
China.
.do-
Philippine Islands,
Malaysia.
.do.-
Souree of introduction
India, South Africa.
Algeria
China
Sumatra.
India
West Indies.
Palestine..
Java .
China, Philippine Islands
China..
Where now available
Orlando, Coconut Grove, and
Eustis, Fla.
Coconut Grove, Fla
Orlando and Eustis, Fla.,
Weslaco, Tex., Fairhope,
Ala.
Orlando, Fla., Weslaco, Tex..
Orlando and Coconut Grove,
Fla.
Orlando and Eustis, Fla
Orlando, Fla., Weslaco, Tex.
.do-
Japan
Philippine Islands.
do
Orlando, Eustis, and Coconut
Grove, Fla., Weslaco, Tex.,
Fairhope, Ala.
Orlando, Eustis, and Coconut
Grove, Fla.
Orlando and Eustis, FIa_-
Orlando, Coconut Grove, and
Eustis, Fla., Summit, Canal
Zone.
.—do-— ..
Remarks
Testing importations in comparison with the
"Florida rough lemon" for stock use and
disease resistance.
Testing for adaptation to a humid climate,
stock adaptability, and disease resistance.
Testing for hardiness, stock adaptability,
fruit quality, and disease resistance; also in
hybridization work. This variety has been
in commercial production for several years
in Florida and the Gulf coast region; has
proved quite hardy.
Not yet fruiting.
Testing for seed content, fruit quality, pro-
ductiveness, disease resistance; used in
hybridizing.
Tests of these introduced varieties indicate
the names are local names for the common
Mexican (or West Indian) lime, similar to
the Florida Key lime.
Used to a limited extent as a stock; fruit
insipid.
Not yet fruiting.
A semihardy, limelike fruit, of possible use
as a stock and serving as an excellent lime
substitute. Crossed with the citrange it
has given rise to an extra-hardy hybrid,
the Glen citrangedin, an excellent "ade"
fruit for the home fruit garden.
A very hardy form of citrus, of possible use
as stock and for breeding purposes.
"Ichang lemon", apparently a hybrid or
large-fruited form.
A hardy lemonlike form of citrus of possible
use as a stock, as a lemon substitute in cool
regions, and for breeding purposes.
Fruits lemonlike but usually too aromatic to
be edible; of possible use as stocks; not
hardy.
Fruits large, oblate, with edible lemonlike
pulp; of vigorous growth; promising as a
stock.
so
to
©
©
T able 6. — Citrus relatives (Rulaceae) introduced by the United Stales Department of Agriculture
Species
Aegle marmelos (L.) Correa
Aeglopsis chevalieri Swingle.
Alalantia citroides Pierre
A. disticha (Blanco) Merr., A.
missionis (Wig.it) Oliv.
Afraegle paniculata (Sehum.
and Thonn.) Engl., Balsamo-
citrus dawei Stapf., Afraegk
gabonensis (Swingle) Engl.
Swinglea glutinosa (Blanco)
-Merr.
Clialcas koenigi (L.) Kurz
Clausena lansiu m (Lour.)
Skeels.
Cilropsis schweinfurthii (Engl.)
Swing, and M. Kell.
C. gabonensis (Engl.) Swingle
and M. Kell.
Eremocitriis glauca (l.indl.)
Swingle.
Common name
Bael fruit .
'Powder pear"
Tabog-
Warn pi.
Cherry orange
Desert kumquat -
Native habitat Source of introduction Where now available
India-
Tropical West Africa
Coehinchine
Cochinchine, Java-
West Africa, central
Africa, French Equa-
torial Africa.
Philippine Islands
India
South China.
Central Africa
French Equatorial Af-
rica.,
Australia
India-
West Africa..
Cochinchinc.
Java
Originalhabitats.
Philippine Islands. .
India
South China-
Central Africa..
Africa
Australia-
Orlando, Coconut Grove,
Eustis, and Lake Alfred,
Pla., Riverside, Calif.,
Mayaguez, P. R., Sum-
mit, Canal Zone,
.do
Orlando, Lake Alfred, and
Coconut Grove, Fla.,
Summit, Canal Zone,
Mayaguez, P. R.
Orlando, Fla
Orlando, Lake Alfred, and
Coconut Grove, Fla.,
Summit, Canal Zone,
Mayaguez, P. R.
.....do..
Orlando and Coconut Grove,
Fla.
Orlando, Lake Alfred, Co-
conut Grove, and Eustis,
Fla., Riverside, Calif.,
Summit, Canal Zone?.
.do-
Orlando, and Eustis, Fla.,
Indio and Riverside,
Calif., Sacaton, Ariz.
Remarks
Deciduous, semihardy, producing an
edible fruit; chiefly used in sherbet.
Fruit not edible, but for testing as stock.
Fruit not edible; for testing as stock; de-
cidedly ornamental — columnar habit,
dark green foliage.
Very resistant to salt and alkali; serves
well as a stock for citrus species, decid-
edly promising for alkali or salty soils.
Fruits not edible; of possible use as
citrus stocks; ornamental; not hardy.
A large forest tree; serves well as a citrus
stock in warm soils; resistant to disease
and vigorous.
Foliage used extensively in the Orient for
flavoring curries; readily propagated
from root cuttings; useful as an orna-
mental; not hardy.
Fruit subacid, small, of good quality; of
possible use as a stock; lemon buds
readily on this stock but on other
citrus species with difficulty.
This species appears to be closely re-
lated to citrus, serves fairly well as a
citrus stock in warm locations; resist-
ant to common citrus diseases. The
large compound leaves and numerous
flowers make the tree decidedly orna-
mental.
Do.
A xerophytic plant of possible use as a
citrus stock in dry regions; a hybrid
has been secured between this species
and a citrange, which is of greatly in-
creased vigor and may serve as a citrus
stock.
to
t/2
CO
I— '
Table 6. — Citrus relatives (Rutaceae) introduced
by the United States Department of Agriculture — -Continued
Species
Common name
Native habitat
Source of introduction
Where now availablo
Remarks
Feronia limonia (L.) Swingle. _ .
Feronielia oblata Swingle ..
F.lucida (Scheff.) Swingle. . .
Fortunella hindsii (Champ.)
Wood apple. ... ..
Krassang _
Kavista Batu
Hong Kong kumquat.
India, Ceylon, Indo-
china.
Cambodia
Java.
India _ .
Cambodia —
China... _
India
Cevlon _
Orlando and Lake Alfred,
Fla., Riverside, Calif.,
Summit, Canal Zone,
Mayaguez, P. R.
. ..do
do
Orlando and Lako Alfred,
Fla.
Orlando, Lake Alfred, and
Coconut Grove, Fla.,
Summit, Canal Zone,
Mayaguez, P. R.
Orlando and Lake Alfred,
Fla.,Summit, Canal Zone,
Mayaguez, P. R., Eustis,
Fla.
Orlando and Lake Alfred,
Fla., Summit, Canal Zone,
Mayaguez, P. R.
Orlando and Coconut Grove,
Fla.
Orlando, Eustis, and Lake
Alfred, Fla., Riverside,
and Indio, Calif., Summit,
Canal Zone, Mayaguez,
P. E.
Orlando and Lake Alfred,
Fla., Summit, Canal Zone,
Mayaguez, P. E.
Orlando and Eustis, Fla.,
and Fair hope, Ala., Win-
ter Haven, Tex.
Fruit used in preserves; tree useful as an
ornamental in warm locations; also
being tested as a stock.
Fruit used as a condiment.
Fruits edible; both species of Feronielia
ornamental and of possible use as a
stock.
Swingle.
Glycosmis pentaphylla (Retz.)
India, Tndo-China_. . .. .
Ceylon _.
India
do
[Australia..
Iudia
China
small and bitter; chiefly of interest as
the plant has proved to be a tetraploid;
crosses are being made with this species
to secure seedlessness; one such cross,
a triploid, has been secured.
Fruits small. Chiefly of use as an orna-
mental; not hardy.
Fruits sometimes used as a condiment.
Chiefly used as an ornamental. Stock
tests gave unions with citrus, but not
vigorous.
Correa.
Hesperethusa crenulata (Eoxb.)
M. Roem.
Lasanga scandcns (Roxb.)
2STaibel
Buch. Ham.
Manilla calozylon (Ridley)
Swingle.
Microcitrus australaska (F.
do....
Australia..
India . . .
China... .
Chiefly of value as an ornamental; not
hardy.
These Australian species are drought-
resistant and are being tested as stocks.
They aresemihardy and useful as orna-
mentals. The fruits are scarcely edi-
ble, except possibly the last named,
which has not yet fruited.
Climbing shrubs.
Muell.) Swingle.
M. australis (Planch.) Swingle.
M. garrowayi (Bailey) Swingle.
.\f. inodora (Bailey) Swingle...
Dooja
Garroway's Finger
lime.
Russell River lime
P. longipedunculata Merr.
Poiicirus trifoliate (L.) Raf
Trifoliate orange . . .
ly hardy and useful as a stock in the
northern limit of citrus culture, espe-
cially for the satsuma orange. Two
forms have been noted, the normal
small-flowered form and a large-flow-
ered form of seemingly greater vigor.
The trifoliate orange has been used in
numerous hybrids, as the citranges and
citrangequats.
00
r>3
O
0
to
to
©
©
Severinia buxifolia (Lam.) Ten. "Box-leaved orange".. South China... | South China
Triphasia trifolia (Burin, f.)
P.Wils.
Lime berry..
I
Unknown. (Widely dis-
tributed in tropical
regions.)
Java.
Orlando, and Eustis, Fla.,
Fairhopo, Ala., Summit,
Oanal Zone, Mayaguez,
P. B.
Orlando, Eustis, and Lake
Alfred, Fla., Riverside,
Calif., Summit, Canal
Zone, Mayaguez., P. R.
This shrubby tree is resistant to salt and
may serve as a citrus stock. It is
chiefly of use in ornamental hedge
plantings. Several strains have been
selected from imported seed of varying
vigor and thorniness. Its immunity
to citrus canker recommends it as a sub-
stitute in hedge plantings for the sus-
ceptible Poncirus trifoliata. Used as a
dwarfing stock, it causes early flower-
ing, hence is useful in hybridizing.
A shrub or dwarf tree, chiefly of use as
an ornamental; resistant to salt; fruits
used sometimes in preserves.
ft
C!
ft
CO
00
h-1
822
YEARBOOK, 1937
Table 7. — Summary of citrus breeding by the United States Department of Agriculture
[Hybrids or selections introduced by the Department, 1892-1934]
1. Hybridization
through con-
trolled cross-
poll ination:
(a) Interspecific:
Fi hybrids
1904
F2 hybrids.
Backcrossing
hybrids on
parent vari-
ety.
(b) Intergeneric:
Bigeneric hy-
brids, Fi gen-
eration.
J 031
1931
Trigeneric hy-
brids, Fi gen-
eration.
1931
1904
190S
1900
1911
1923
1923
1932
1933
Sanford, Rusk, Wil-
litts, and Phelps
citranges.
Morton citrange
Colman, Rustic, and
Savage citranges.
Saunders and Cun-
ningham citranges.
Eustis and Lakeland
limequats.
Tavares limequat.
Nippon kumquat,
"orangequat".
Thomasville and Tel-
fair citrangequats.
Sinton citrangequat.-
Parentage
Sampson and Thorn-
ton tangelos.
Orlando (Lake), Sem-
inole, Minneola, Ya-
laha tangelos.
Clement tangelo
Umatilla tangelo
Perrine lemon
San Jacinto tangelo.
Wekiwa tangelo
Dancy tangerine X
Bowengrapefiuit.
-do.
Clementine tangerine X
Bowen grapefruit.
Satsuma orange X Kuby
orange.
Genoa lemon X Mexi-
can lime.
Seedling segregate of an
unnamed tangelo of
little promise.
Sampson tangelo x
grapefruit.
Trifoliate orange (Pon-
cirus trifoliata) X
sweet orange (Citrus
sinensis) .
Mexican lime (Citrus
auranlifolia) X round
kumquat (Fortunella
japonica).
Lime X oval kumquat
(F. margarita).
Satsuma orange (Citrus
nobilis var. unshiu) X
Meiwa kumquat (For-
tunella crassifolia).
Wiliitts citrange X oval
kumquat (Fortunella
margarita).
Rusk citrange X oval
kumquat.
Remarks
These early introductions
proved susceptible to
scab and were poor ship-
pers, with a short season
of maturity.
This series of tangelos in-
troduced in 1931 gave
varieties high in quality,
maturing from October to
May, scab-resistant, and
of good shipping quality.
A soft-fleshed hybrid for
the home fruit garden;
not recommended for
commercial planting.
Classed with the tangelo
group whichit resembles;
very late maturing; scab-
resistant.
Fruit of size, shape, and
quality of commercial
lemon; highly resistant
to scab and withertip;
vigorous and productive.
Adapted to conditions in
the hot interior valleys
of the Southwest, where
most tangelos have been
disappointing.
Tree resembles pollen par-
ent (Sampson) though less
vigorous; fruit small,
sweet, pink-fleshed, un-
like either parent.
The citranges with one
exception (Rusk) had
the trifoliate orange as
t he female parent. They
failed in producing a
hardy ediblo orange, ow-
ing to an excess of acrid
oil in rind and pulp, but
are proving useful as
stocks and for further
work in hybridization.
The limequats have proved
similar to the lime in
fruit quality, but much
hardier and resistant to
lime withertip.
This "hybrid may be util-
ized in preserving like
the kumquats, but is a
much larger fruit borno
on a more vigorous
hardy tree. It also fur-
nishes an excellent ade,
owing to its acid, deep
orange pulp.
'In these crosses the ob-
jectionable oil of the cit
range is reduced so that
the fruits may serve as
hardy lime substitutes
in making ade. The
Thomasville also proved
immune to citrus canker,
a character derived from
the kumquat parent.
CITRUS FRUITS
823
Table 7. — Summary of citrus breeding by the United States Department of
Agriculture- — Continued
[Hybrids or selections introduced by the Department, 181)2-1934]
breeding procedure
Trigeneric hybrids,
Fi generation?
2. Selection:
(a) Seedlings (apo-
gamie or non-
hybrid) .
Bud selection i__
Intro-! Name ot hyb™d or
duced
1908
1906
1931
1032
1921
-36
variety
Glen citrangedin .
"Wcshart and Trimble
tangerines.
Everglade lime..
Palmetto lime...
Davis (tittle River)
grapefruit.
Silverhill
orange.
satsuraa
Oklawaha sour orange.
Valencia, Lug (Luo
Gun Gong), Pine-
apple, ParsonBrown,
and Homosass a
oranges; King man-
darin; Daney and
Oneco tangerines;
Marsh, Duncan,
Hall, Davis, Foster,
and Thompson
grapefruit.
Parentage
Willittscitrange X oala-
mondin (Citrus mitis).
Derived from Daney
cross-pollinated seed,
but not hybrids.
{Grown from lime seed
from cross-pollinated
fruits, but not hybrids.
Original seedling from
cross-pollinated fruit
of a seedy grapefruit
(with Danoytangerine
pollen); not a hybrid.
Original seedling from
cross-pollinated Owari
satsuma (sweet orange
pollen) , but not a hy-
brid.
Derived from cross-polli-
natedsour orange (sour
pummelo pollen used),
but not a hybrid.
Bud wood secured from
performance record
trees; several progeny
rows of each variety
budded and grown
under uniform condi-
tions with rocord of
yield, and special at-
tention to the produc-
tion of any off-type
fruit. (1 progeny of
Luo was discarded and
replaced, owing to
tendency to produce
ridged fruits. A bud
sport of the Parson
Brown has been stud-
ied over a period of
years and seems to be
a chimeral mutation).
Kemarkr
In this cross the objection-
able oil content of theci-
trange is eliminated, giv-
ing rise to an ade fruit
similar to the calamon-
din but much more
hardy.
Seedlings exhibiting ap-
parently extra vigor and
producing fruits of larger
size than tho parent
variety.
Apparently extra vigorous
strains of the Mexican
lime with some indica-
tions of wilhortip resist-
ance.
This seedling produced a
new type of seedless
grapefruit (1-fi seeds)
with the fruit quality of
the seedy grapefruit; in-
dications aro that it is a
superior canning variety.
This variety exhibits extra
vigor and hard mess, with
large-sized fruit of good
cniality.
Troc of vigorous productive
character with largo thick
-rind fruits adapted to use
in marmalade prepara-
tion. This character has
been transmitted in bud-
ded progeny.
Under the terms of the co-
operative agreement the
disposition of budwood
from the progeny grove
is in the hands of the
Florida Agricultural Ex-
periment Station, and
considerable demand has
developed in recent years
among growers and nurs-
erymen for tliis true-to-
type budwood of stand-
ard varieties. Tho ex-
periment station, also
under the cooperative
agreement, is testing the
new citrus hybrids in-
troduced by the Depart-
ment and maintains a
collection of tho citrus
relatives furnished by the
Department.
' Standard orange varieties as listed by the standardization committee of the Florida Citrus Seminar
1916; other citrus varieties selected and propagated iu cooperation with the Florida Agricultural Experiment
Station at the Citrus Experimental Station, Lake Alfred, Fla. For bud selection work In California, see
table 8.
824
YEARBOOK, 1937
Table 8. — Bud mutations in citrus discovered by Shamel and coworkers, of the United
States Department of Agriculture, in cooperation with the California Citrus Experiment
Station, Riverside, Calif., 1909-36
SWEET ORANGE (WASHINGTON NAVEL STRAINS)
Strains
Characteristics
Date dis-
covered
Remarks
Superior strains:
Improved Washing-
ton.
Uniformly heavy production of uni-
formly desirable oranges.
Early maturity, resistant to "June
drop."
Fruits generally lacking juice and
flavor.
1909
1925
1909
1913
1909
1915
1914
1909
1915
1909
1909
1914
1909
1909
1914
1910
1909
1909
1909
1915
1921
1909-30
1,402,950 selected buds sold by
Fruit Growers Supply Co.
and estimated 2,000,000other-
wise distributed.
Inferior strains:
Unproductive
districts.
Trees top-worked to Improved
Washington.
Do.
Low production, poor fruit, rank
growth.
"Willow-Leaf
Do.
Dry
Do.
Yellow
Do.
Brown-Spotted ..
Do.
Do.
Golden Nugget
Dual
Lacking in juice; pale color of peel...
Uneven texture of rind..
Deeply and uniformly ridged fruit __
Shallow and uniformly ridged peel-.
Very shallow, narrowly seamed peel-
Broadly and evenly ridged peel . ...
Flattened.shape of fruit .-
Pyriform shape of fruit -.
Do.
Do.
Do.
Ribbed
Do.
Do.
Fluted_. ._ .
Flattened
Do.
Do.
Do.
Elliptical .
Do.
Small, pear-shaped fruit, enclosed
navels.
Rolled leaves, unproductive
Many strains of minor economic
" importance but originating from
bud mutations.
Do.
Rollod-Lcaf
Do.
Minor importance. .
Do.
SWEET ORANGE (VALENCIA STRAINS)
Superior strain:
Improved Valencia .
Inferior strains:
Unproductive..
Willow-Leaf
Dwarf
Persistent-Style..
Flattened
Long...
Fluted
Corrugated
Ridged
Coarse
Yellow
Misshapen-Leaf..
Small Smooth
Variegated
Minor strains..
Uniformly heavy production, uni- : 1912
formly good quality of fruit.
Very low yields I 19J2
Narrow leaves, small fruits
Small tree, low yields
Style tends to remain with fruit
Flattened shape of fruit
Long or oblong shape of fruit
Broadly, evenly, and smoothly
ribbed fruit.
Deeply ridged, rough texture of rinds
Sharply and unevenly ridged rinds..
Coarse, rough texture of rinds
Pale color of peel
Irregularly shaped leaves, low yields.
Very small fruit, smooth, very thin
rinds.
Leaves light and dark green
Many economically unimportant I
strains differing in treo and fruit i
characteristics from all others.
1912
1912
1915
1912
1912
1912
1012
1912
1912
1912
1914
1912
1915
1912-36
2,337,000 selected buds sold by
Fruit Growers Supply Co.,
and estimated 2,250,000 buds
otherwiso distributed.
Trees top-worked to Improved
Valencia.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
LEMON (EUREKA STRAINS)
Superior strain:
Improved Eureka.
Heavy yields of uniformly good
lemons.
1911
767,000 selected buds sold by
Fruit Growers Supply Co.,
and estimated 1,250,000 buds
otherwise distributed.
CITRUS FRUITS
825
Table 8. — Bud mutations in citrus discovered by Shamel and coworkers, of the United
States Department of Agriculture, in cooperation with the California Citrus Experiment
Station, Riverside, Calif., 1909-36 — Continued
T,EMON (EUREKA STRAINS) -Continued
Strains
Inferior strains:
Small-open
Pear-shape
Shade-tree
Unproductive-
Corrugated
Ribbed
Variegated
Striped-
Crumpled leaf.
Minor strains.
Characteristics
Small-sized fruits.
Pyriform-shaped fruits ,
Vigorous tree growth; coarse, thick
rinds.
Very low yields.
Strongly ridged and coarse-textured
rinds.
Evenly ribbed texture of rinds
Leaves light and dark green, fruits
ridged.
Light stripes on fruits
Crumpled appearing leaves, low
yields.
Many strains originating from bud
mutations of minor economic im-
portance.
Date dis-
covered
1011
191.1
1911
1911
1911
1912
1912
1911
1911-35
Remarks
Trees top-worked to Improved
Eureka.
Do.
"Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
LEMON (LISBON STRAINS)
Superior strains:
Improved Lisbon...
Dense-productive...
Inferior strains:
Ilcavy production of uniformly de-
sirable fruits.
Vigorous growth, resistant to wind
damage.
Spreading tree growth, susceptible to
sunburn.
1913
1913
1913
1913
1913
1913
1913
1013
1920
1013-30
80,215 selected buds sold by
Fruit Growers Supply Co.,
and estimated 125,000 buds
otherwise distributed.
Do.
Lisbon.
Do.
Ribbed
Do.
Corrugated
Collared
Heavily ridged and very coarse-tex-
tured rinds.
Bottlo-sbaped with necked stem
ends.
Light-colored stripes on rinds
Do.
Do.
Do.
Do.
Minor strains
Many strains of minor commercial
importance but of scientific in-
terest. •
Do.
GRAPEFRUIT (MARSH STRAIN'S)
Superior strains :
Improved marsh
Heavy production of uniformly
sirable fruits.
de-
1010
1927
1910
1010
1910
1910-37
1,262,757 buds sold by Fruit
Growers Supply Co. and es-
timated 750,000 buds other-
wise distributed.
Inferior strains:
Marsh.
Do.
Pear shape
Minor strains
Do.
Several strains of minor commercial
importance but of scientific in-
terest.
Do.
TANGERINE (DANCY STRAIN)
Superior strain:
Improved Dancy.
More regularly productive..
1915
56,973 selected buds sold by
Fruit Growers Supply Co.
138904°— 37-
-53 ++
826 YEARBOOK, 193 7
Table 8. — Bud mutations in citrus discovered by Shamel and coworkers, of the United
States Department of Agriculture, in cooperation ivith the California Citrus Experiment
Station, Riverside, Calif., 1909-36 — Continued
LFME STRAINS
Strains j Characteristics j Duto dis-
! covered
Superior strains: :
Improved Mexican, j Selected for size of fruits ' 1921
Improved Bearss | Selected for heavier production. ' 192S
! I
5,1 63 selected buds sold by
Fruit Growers Supply Co.
Note. — The article entitled Improvement of Subtropical Fruits other than Citrus, by
Hamilton P. Traub and T. Ralph Robinson, appears in the 1937 Yearbook Separate on
Improvement of Subtropical Fruits.
NUT BREEDING
H. L. CRANE, Principal Horticulturist, C. A.
REED, Associate Pomologist, and M. N. WOOD,
Pomologist, Division of Fruit and VegeLable
Crops and Diseases, Bureau of Plant Industry
I
IMPROVEMENT in nuts by some sort of selection was probably
brought about originally by cave men, wild animals, and birds. The
more toothsome nuts were the ones chiefly sought after and carried
from place to place or hidden in caches. Weaker creatures, forced
by stronger rivals from warmer and more comfortable localities, were
obliged to steal their food and carry it to places safer for themselves
although often less favorable for the nuts, which they might lose, to
take root and thrive. It was by such means that the productive
areas were gradually expanded and greater hardiness and ability to
grow at higher or lower altitudes wore developed. Ocean currents,
which have much to do with the distribution of many kinds of seeds,
appear to have had little part in the carrying of Temperate Zone nuts
from place to place.
Planters have as yet made little systematic effort to breed superior
varieties of any kind of nuts by hybridization. This is doubtless
because of the great abundance of wild nuts that in the past could be
had for the gathering, and more recently because of the practical
difficulties standing in the way of tree breeding, especially the time
required to complete the cycle of a generation. The countless cen-
turies of crude selection through which such cultivated forms as
filberts, almonds, Persian (English) walnuts, and European chestnuts
have passed have tended so to fix the types that to a large extent
they now come fairly true to type from seed, although in this coun-
try none but grafted trees of selected varieties are planted, except
when only seedlings are to be had. Most of the nuts now on the
world market are from seedling trees. The extensive multiplication of
superior varieties resulting from selective or controlled breeding is still
greatly handicapped by practical difficulties in propagation, especially
m the case of the more difficult species of walnut and hickory.
CHESTNUT
Chestnut improvement in this country has developed along four dis-
tinct lines — by selection from native seedlings, by the introduction of
Old World species and the continuance of selection with them, by
natural hybridization among various species and varieties when grown
together, and by controlled hybridization, the newest and most
promising method.
Breeding by selection from native species has contributed little, as
few varieties developed by this method have become prominent.
827
828 YEARBOOK, 1937
The majority so originated are now obsolete, and it would probably
be impossible to establish the purity of the supposed American
parentage of the very few still grown by nurserymen. Numbers of
hybrids exist that are plainly the result of natural crossing between
native species, but none has commercial value.
Because the American chestnut is very susceptible to what is known
as blight, a fatal fungus disease from the Orient, which was first dis-
covered in this country in 1904 and has since spread over practically
the entire East, the chief interest in chestnut planting now lies in the
use of species from the Old World.
Altogether eight species of chestnuts, including the closely related
chinquapins, have been used in the chestnut developments of this
country. Formerly the most important and abundant of these species
was the American chestnut, Oastanea dentata (Marsh.) Borkh. This
had a natural range extending from lower New England westward to
southeastern Michigan and southward to northern Georgia and east-
ern Arkansas. As a tree it was one of the largest growing species of
the Eastern States ; a trunk diameter of 6 to 7 feet and a limb spread
of 50 or more feet from the center of the tree were not uncommon with
trees standing in the open. As a forest tree it was once a dominant
species over large mountain areas of the Appalachian Range from
Pennsylvania south to the Carolinas and eastern Tennessee. In these
regions a height of more than 100 feet with a diameter at the base of
WHEN the chestnut blight wiped out this magnificent eastern forest
tree in the early part of the present century, chestnut breeding
became a pressing need. The most promising of all material at
present is the Chinese chestnut. It is much more blight-resistant
than any others, and the nuts combine the large size of the European
chestnut with the sweetness of the American. The Japanese chest-
nut, which has considerable blight resistance, unfortunately produces
nuts that are usually negative in flavor, but it may be useful in
breeding. Selection and hybridization are being actively carried on
by the Department of Agriculture with the object of developing
varieties for both commercial and home growing that will be resistant
to blight and if possible to weevils, and hardy enough to grow through-
out the chestnut range; bear heavy annual crops, beginning at a
fairly young age; bear not more than three rather large nuts to the
bur, which must separate automatically; have fine texture, good
flavor, and good keeping quality; be attractive in appearance and
not subject to shell splitting; and have an inner skin or pellicle that
will not adhere to the kernel.
NUTS 829
not more than 2 to 3 feet was common. The trees were much sought
after as material for telephone poles, fence rails, mine props, and
other similar purposes where important factors were abundance,
uniformity of size, freedom from knots, ease of splitting, and dura-
bility both above and below ground.
The burs of the American chestnut are relatively large and the
spines long and compound. The nuts arc coated at the apex, or
nearly to the middle, with thick, pale down. The kernels are very
sweet and palatable. Selected nuts of this species are among the
most delicious of any known. They were thought to be the choicest
of all chestnuts until the arrival of certain oriental strains, which
proved to be their equal.
Two other species of Castanea are indigenous to this country. Both
are chinquapins and therefore not true chestnuts, although closely
related. These are much alike and are restricted to more limited
ranges than the American chestnut. The trees are dwarfish or
shrubby in habit, and the nuts are borne singly in small burs, which
form in racemes or long, stringlike clusters. The nuts are small but
very sweet. The better known of the two species is the tree or com-
mon chinquapin, C. pumila (L.) Mill. This occurs chiefly in the
Southeast, from central Pennsylvania to Florida and west to Texas.
The species occasionally forms hybrids with the American chestnut.
One such hybrid tree was found, probably about 1895, by the late
J. G. Rush, of West Willow, Pa. This was propagated and dissemi-
nated to some extent by Rush, after whom it had been named, but
after a few years of experimentation he cut down the trees as he came
to regard the variety as merely a novelty of little practical value.
However, trees are still grown by some who find it an interesting form
of considerable value for home use. The other species of chinquapin
is the so-called alder-leaved or trailing chinquapin, C. alniiolia Nutt.,
a low-growing shrub confined to certain localities in the South Atlantic
States and occurring rarely as far west as central Louisiana. This
species has the peculiarity of reproducing itself by means of under-
ground stems and forming dense thickets.
Developments From Early Introductions
The first foreign chestnut introduced into this country was the
European or Spanish chestnut, Castanea satita Mill. The earliest
record that has so far come to light appears in the notes of Thomas
Jefferson, according to Bailey (o),1 and shows that scions of a "French
chestnut" were grafted by liim in 1773 at Ms home, Monticello, near
Charlottesville, Va. This species also is a large tree, growing in
Europe to 100 feet in height and 30 feet in circumference, though in
this country it seldom grows larger than a medium-sized apple tree.
The trees are precocious and under American conditions very fruitful.
The nuts are large and usually very good but rarely equal in quality
to the average American chestnut. The tree is scarcely less fatally
subject to blight than the American chestnut and therefore is not
longer being planted in blight-affected zones.
The second foreign species to become important in this country was
the Japanese chestnut, Castanea crenata Sieb. and Zucc. This is a
i Italic numbers in parentheses refer to Literature Cited, p. 881.
830 YEARBOOK, 1937
relatively small tree or shrub growing to 30 feet in height. The
species is characterized by small stiff leaves, great fruitfulness, and
large size of nuts, which are sometimes enormous. Occasionally the
nuts are very good but as a rule the flavor is mild or neutral and the
texture somewhat coarse. Quite commonly the pellicle or skin cov-
ering the kernel is thick or even woody. It may adhere tightly and
be removable only by paring with a knife. The species is quite
resistant to blight, although in the experience of the Division of
Forest Pathology, Bureau of Plant Industry, United States Depart-
ment of Agriculture, it is exceeded somewhat in this respect by the
Chinese or hairy chestnut (C. mollissima Bl.)
The Chinese chestnut tree is intermediate in size between the
Exiropean species as grown in this country and the American species.
It was known in the United States to a slight extent as early as 1853,
but it may be said to have been introduced by the Department of
Agriculture in 1907. While very young it tends to develop many
lateral branches with little tendency toward a central loader. Later
on it assumes more definite shape and becomes a standard tree. It
begins bearing relatively early and is sometimes highly prolific. The
outstanding feature of this species, in addition to the fact that it is
apparently more resistant to blight than any other, is the excellence
of the nuts, many of which are as large as the European and as sweet
as the best American nuts. They are attractive in appearance, often
being of a rich mahogany brown and frequently glossy. There is
little down on the surface and that only at the apex. When in the
proper stage of maturity the pellicle of the kernels tends to adhere to
the shells rather than the kernels.
In 1799 Irenee du Pont came to New Jersey from France and "after
a residence at Bergen Point, where he took much pleasure in propa-
gating a number of European seeds and plants received from Franco,
removed to Delaware in 1802 and settled on the Brandywino, where ho
established the famous Du Pont Powder Mills" {26). At both places
Du Pont paid special attention to bringing European chestnuts into
this country, chiefly from his native home, and to disseminating both
these and their offspring among his friends and acquaintances.
Records show that many varieties of European chestnuts, which
during the eighties and nineties became prominent in this country,
were derived from Du Pont introductions.
Powell (26) records that scions taken from one of the Du Pont
trees and grafted in 1850 on stocks of the native species gave rise to a
variety named Darlington, after Thomas Darlington, of West Chester,
Pa., who was intrumental in disseminating the variety. This may
have been the first chestnut grafting in this country after that of
Jefferson.
Beginning in the early eighties and continuing for about two decades,
a large number of seedlings of European species were named ami
propagated. Some of these were popularly supposed to have been
hybrids with the American species, but this was not proved. A few
were extensively used in top- working coppice growth in cut-over
chestnut forest lands of eastern Pennsylvania, Now Jersey, northern
Maryland, and northern Virginia. All proved to be fatally suscep-
tible to blight. The best-known varieties were Paragon, Numbo,
NUTS 831
Ridgeley, Cooper, and Scott. These are now rarely grown and are
found only in districts outside of blight-affected zones. Even there
they are being replaced by better varieties.
A more recent group of varieties, thought by some to be partially
or entirely European in origin, although regarded by the originator
as pure American, was developed by the late E. A. Eiehl, of Godfrey,
111., from seedlings of unknown origin obtained from the nursery of
Charles A. Green, Rochester, N. i., and planted about 1890. To
hasten the trees into early bearing Riehl grafted scions from them into
the top of an old seedling American chestnut. The resulting nuts so
impressed him that he named the variety Rochester. From Rochester
seedlings he selected and named a number of still better varieties such
as Progress, Fuller, Champion, and Van Fleet. Gibbons, from the
same source, has been added since Riehl's death in 1924. However,
these varieties, like all others having either European or American
parentage, are very susceptible to blight, and when once affected
the trees perish quickly.
The Japanese chestnut, Castanea crenata, has also been a source of
numerous varieties having desirable characteristics. According to
Fuller (14), the earliest recorded introduction of this species took
place in 1876, when a number of trees were received by S. B. Parsons
& Co., nurserymen at Flushing, N. Y., from Thomas Hogg, a skilled
horticulturist of this country who spent several years in Japan collect-
ing rare kinds of trees and shrubs. These trees fruited in 1878 and
soon attracted attention on account of the large size and excellent
quality of the nuts and their precocious bearing habits. According to
Powell (26), "Parson's Japan" was well known for a few years, but
presently disappeared.
In 1882 the late William Parry, of Parry, N. J., imported 1,000
grafted trees from Japan, and from them a single tree, the Parry, was
finally selected and became the progenitor of many varieties. In
1886 Luther Burbank, of Santa Rosa, Calif., planted large Japanese
chestnuts collected for him in Japan, and from over 10,000 bearing
seedlings he selected 3 as worthy of perpetuation — Hale, Coe, and
McFarland. In 1915 he introduced another variety, Miracle, also of
Japanese origin. Groups of Japanese varieties were developed by
J. W. Kerr, Denton, Md., and J. W. Killen, Felton, Del., probably
from seed procured from Parry or other importers. Each of these men
introduced a considerable number of carefully chosen varieties, of
which Black, Felton, Kent, Kerr, Killen, and Martin are still being
grown occasionally on the Chesapeake Peninsula.
Developments and extensive plantings of Japanese and European
chestnut varieties made from 30 to 40 years ago included those of the
Albion Chestnut Co. at Clementon, N. J.; the Mammoth Chestnut
Co. and Joseph Williams at Riverton, N. J.; Joseph T. Lovett at
Emilie, Pa.; the Paragon Nut & Fruit Co., Lancaster, Pa.; and C. K.
Sober, Lewisburg, Pa.
Breeding by Hybridization
Chestnut breeding by controlled cross-pollination appears to have
been the first work of the kind undertaken in this country, if not in the
world, with any species of nut, and a number of apparently good
832 YEARBOOK, 1937
varieties were so developed. Unfortunately, chestnut blight entered
from the Orient at about the time the hybrids were ready to be intro-
duced, and none proved to have sufficient resistance to this disease to
justify extensive planting. This early work was undertaken almost
simultaneously by two men wholly unknown to each other and living
in remote sections of the country. Both died about the time that
material was becoming available with which the next steps in breeding
and the development of blight-resistant varieties might hav o been taken.
The first work appears to have been that begun in 1888 by George W.
Endicott, of Villa Ridge, 111., a veteran of the Civil War, farmer, and
practical fruit grower. In that year ho began a search, for an American
chestnut tree blossoming early enough to furnish pollen for use on the
pistillate flowers of the Giant (Japan Giant) variety (89), which was
prolific but not of high grade. It was as a result of such a cross
made by him in 1895 that he developed the Boone variety.
The next hybridizing work with, chestmits began in 1894 when
Van Fleet (43) well known in this country as a breeder of roses and
small fruits, who was then an associate editor of the Rural New York-
er, dusted pollen of a native chestnut on the pistillate flowers of Para-
gon, a popular variety of European parentage. The resulting seed-
lings were grown on the private grounds of Van Fleet in Little Silver,
N. J. Coming into bearing in 1906, they showed unmistakable signs
of hybridity and might have become valuable had they not been seri-
ously attacked by chestnut blight a year or so after beginning to fruit.
The period of Van Fleet's most important work in chestnut breeding
began in 1900. Between then and the time of his death in 1921 he
made thousands of crosses, using many species and growing hybrids
through several successive generations. His earlier work largely
consisted of crossing the native chinquapin, Castanea jmmila, with
such leading European varieties as Numbo and Paragon and such
Japanese sorts as Parry (Parry's Giant), Killen, and Hale. To some
extent he also used pollen from native wild trees of tho American
chestnut. In his later work he included the Chinese chestnut, C.
mollissima.
The final results of Van Fleet's work were practically nil, so far as
production of commercial varieties was concerned, for the reason that
all hybrids having any degree of either American or European parent-
age proved susceptible to blight and soon succumbed. However, one
hybrid, designated as S-8 from its position in the orchard, and be-
lieved to have been the result of a cross of chinquapin with Japanese
chestnut, is being tested under controlled infection conditions for
possible resistance. Recent reports indicate that this hybrid is not
sufficiently resistant to blight to justify general planting.
The work of both Endicott and Van Fleet is important because it
gave information as to the possibility of using different species in
breeding and it developed a useful technique.
The chestnut breeding of Van Fleet has been continued and ex-
panded by the Division of Forest Pathology of the Bureau of Plant
Industry with G. F. Gravatt and R. B. Clapper in charge. Thousands
of crosses have been made involving the eight species, and the work
has been carried through several successive generations. Selections
are now being made of the most promising individuals for varietal use.
NUTS 833
Defects and Merits of Present Varieties
Present varieties of the chestnut have many serious defects, of
which susceptibility to certain natural enemies is most prominent.
One of these enemies is chestnut blight, the fungus disease already
referred to as attacking all species in varying degrees. It has spread
rapidly over the native range of the chestnut since it was first dis-
covered on Long Island early in the present century. It is most
serious with the American and next with the European chestnut.
Japanese varieties and seedlings are resistant. Varieties of the
Chinese chestnut, Castanea mollissima, appear to be even more re-
sistant, and as the nuts are generally superior to those of the Japanese
chestnut, the species appears to offer greater promise for orchard
planting.
Chestnut weevils are native pests attacking all choice varieties with
about equal severity. If any chestnuts are less subject to this menace
than others they are the largest and least palatable of those from
Japan. The adult weevil deposits its eggs deep in the immature
kernel when the nut is partially grown. One egg or many may be
placed in each nut. They hatch at about the time the nuts ripen, and
the larvae feed and fatten inside the nut, then bore their way out and
enter the ground for the winter stage. In early-ripening varieties
these insects often do not appear until after the nuts have arrived in
the market. A few days later, especially if the weather is warm, and
about the time the nuts reach the consumer, the white larvae or grub-
like insects emerge. In severe infestations these pests will be seen
crawling in all directions, or if a nut is cut open they will be found in
various parts of the kernel, to the disgust of the would-be consumer.
Whether blight, which may completely kill the tree and end the
story, or weevils, which do not affect the tree but ruin the nuts after
they are grown, is the more seriously limiting factor in chestnut
growing is an open question. No method of spraying has been found
sufficiently effective with either to be worth while. However, as
already stated, the blight-resistant Chinese and Japanese species
appear to offer a practical solution to the former evil, and to some
extent planting chestnut trees only in thickly populated poultry yards
is being found successful in controlling the latter. One way of avoid-
ing weevil damage would be to plant only in parts of the country
where this pest is not known to be present. As time goes on, more
satisfactory means of controlling or obviating both of these natural
enemies may be developed.
Other defects of chestnuts are tardy bearing; shy bearing or over-
productiveness; lateness in time of maturity; failure of the burs to
open and discharge the nuts automatically; variability in size of nuts;
a tendency for the shells to split badly and thus expose the kernel to
weather; thickness of pellicle; tight adherence of pellicle to the kernel ;
and coarseness, lack of sweetness, and poor keeping qualities. No
known varieties are free from all of these objectionable features. With
some exceptions, the American chestnut bears nuts that are small and
unattractive in appearance, and the pellicle of the kernel adheres
tightly, although it is so thin as not to be obj ectionable. The trees grow
to immense size but are tardy in beginning to bear and seldom bear
834 YEARBOOK, 1937
heavily. Besides being fatally subject to blight, the European chestnut
is usually of medium flavor, the pellicle adheres tightly to the kernel,
and the texture is seldom as fine as that of the American and Chinese
species. The chief defects of the Japanese chestnut are poor flavor and
coarseness of kernel, thickness and even woodiness of pellicle, and
usually tight adherence of pellicle to kernel. As a rule Japanese
chestnuts are good to eat only when cooked. The Chinese chestnut
also has its defects, but owing to its newness in this country it has not
yet been fully appraised. As already noted, it is subject to weevils
and somewhat so to blight. Young trees are slow in assuming dis-
tinct tree form. While of nursery age the little trees are very subject
to winter inj ury . N othing is known as to the self -sterility or inter-ster-
ility of Chinese varieties. Very few have yet been named and none
has been thoroughly tested. The real merits and defects of this species
can be determined only by wide observation over a period of years.
The good characteristics of chestnuts are fairly well distributed
among the various species and varieties. The American chestnut
makes the largest and most upright tree, is by far the best for timber
purposes, and the kernels are the most uniformly sweet. The Euro-
pean chestnut bears well and annually, beginning at a moderately
early age. The tree does not ordinarily assume such great size as to
be objectionable to the orchardist. The nuts are of good commercial
size, and those of some varieties are sweet and highly palatable. Nuts
of this species often bring top prices. The Japanese chestnut is out-
standing in its normal precocity, prolificacy, habit of annual bearing,
and large size and attractive appearance of the nuts. The species is
highly resistant to blight and would need only the sweetness, fineness of
texture, and palatability of the best American and Chinese chestnuts,
and the automatic separation of pellicle from kernel, characteristic of
some of the latter, to rank among the favorites with both growers and
consumers. There are a few Japanese varieties of such merit as to give
promise of orchard usefulness.
As a rule, all chestnuts are more or less self-sterile and bear better
when interplanted with other varieties or seedlings.
The Chinese chestnut appears at this time to offer the greatest
opportunity for improvement by breeding. The trees do not attain
the large size of the American species, which is undesirable, but they do
become somewhat larger than the Japanese, which in this country
seldom exceed the apple tree in size. The Chinese chestnut is highly
resistant to blight, and so far as observed the best seedlings and varie-
ties bear freely without being overproductive. Some of the heaviest-
bearing trees of this species in a seedling orchard located at the United
Station Pecan Field Station, Albany, Ga., now 10 or 12 years of age,
are annually producing from 50 to 70 pounds of nuts each. The finest
nuts of the Chinese species are about all that could be desired. The
largest are equal in size to the average chestnuts imported from Italy
as commonly seen in eastern cities from midfall until after the holidays.
Typically the Chinese chestnuts are of dark, chocolate-brown color,
overlain with thick to thin gray or whitish down that may cover the
greater part of the exposed surface or be confined to a small area
immediately surrounding the apex. They are commonly glossy and
attractive. Some are only mildly sweet, but others are excellent.
NUTS 835
With regard to automatic separation of nuts from the burs, as well
as time of maturity of crop, marked variability exists among seedlings
and varieties of all species. As a rule the Chinese and Japanese chest-
nuts ripen earlier and separate themselves from the burs better than
either European or American chestnuts.
Present Breeding Work
Breeding work is largely confined to the Chinese chestnuts, though
the Japanese may be useful to some extent. The present work in
improving the Chinese chestnut necessarily involves the selection of
seedlings promising as new varieties and the use of such varieties in
actual breeding by hybridization. During the past several years the
United States Department of Agriculture, Bureau of Plant Industry,
through its Divisions of Fruit and Vegetable Crops and Diseases and
of Forest Pathology, has examined nuts from several hundred trees
in various parts of the country. Probably 100 seedlings are now under
observation. Scions of many of the best have been grafted upon
nursery stocks and are now on their way to early bearing. Three of
the trees tentatively selected in 1930 have been propagated by
individuals outside the Department and to some extent are being
commercialized, although they are by no means fully tested or ap-
proved by the Bureau. One of these is known as Carr, after R. D . Carr,
Magnolia, N. C, to whom the original tree was sent by the Bureau in
1919. Another is Hobson, so called after James Hobson, Jasper,
Ga., to whom, with a number of others, it was sent in 1919. The
third variety is Zimmerman. This was selected by the Bureau from
a lot of seedlings grown by G. A. Zimmerman from nuts imported by
him in 1924 through Nanking University, Nanking, China.
The trees under observation also include a number of Japanese
seedlings that now appear to be of considerable promise. The
majority of these are of recent origin, as they were brought to light in
1929 as a result of cash prizes financed that year by John Harvey
Kellogg, Battle Creek, Mich., through the Northern Nut Growers'
Association.
The aims in breeding are to produce varieties that will be of value
for the general market or the home or both. The desired character-
istics at present are resistance to blight and weevils, heavy annual
bearing, moderate precocity, early and quick maturity of nuts ahead
of frosts, automatic separation of the nut from the burs, not more than
three nuts to the bur, large but not of too great size, attractive appear-
ance, freedom from shell splitting, thinness of pellicle, automatic
separation of kernel from pellicle, fine texture, good flavor, and good
keeping quality. Hardiness in all parts of the native or adapted
range of the chestnut is also important.
In the appendix will be found a list of persons now engaged in the
improvement of the chestnut through breeding.
FILBERT
The term "filbert" is used in this article in accordance with the popular
American usage and is understood to imply a superior type of nut of
the botanical genus Corylus. The term "hazel" is used for the inferior
and smaller nuts. In Europe the distinction is drawn upon the basis
836 YEARBOOK, 193 7
of length of husk in proportion to that of the nuts. Those that have
husks no longer than the nuts are called hazels, while those with
husks longer than the nuts are called filberts. This distinction is
difficult to follow, once the husks have been removed.
At least four species of Corylus are under cultivation for nut produc-
tion. Two of these are tree forms attaining a height of 80 to 125 feet.
Both are commonly called hazels, as the nuts they bear are rather
small, thick-shelled, and inferior in edibility. One is the Turkish
or Constantinople hazel, C. colurna L., of southeastern Europe and
western Asia. According to Rehder {28), this species was introduced
in 1853. It is extremely hardy, doing well in western New York,
where three fine trees 50 feet tall are to be seen in Highland Park,
Rochester. It is used in this country for ornamental planting and as
a stock on which to graft superior varieties of the European filbert.
The latter use is still in the experimental stage and is not recommended
for commercial purposes. The other tree species is the Chinese hazel,
C. chinensis Franch., which Rehder states was introduced into this
country in 1895. Its usefulness for stock or other purposes has not
yet been determined.
Two native species of Corylus that are being used to some slight
extent in the development of varieties are the eastern hazel, C. ameri-
cana Marsh., and the beaked hazel, C cornuta Marsh. Both are
shrubby species producing nuts ordinarily of little value. The
former has much the greater range in this country, as it is common
from the Lakes to the Gulf, whereas the latter occurs only in the
northernmost States. Nuts of the eastern hazel have husks longer
than the nuts, and they develop as overlapping valves opening at one
or both sides to the base. The beaked hazel has long, tubular, and
thickly spiny husks, which remain tightly closed. A form found on
the Pacific coast, greatly resembling the latter and known by some
authorities as C. califomica Rose, but by others as a form of C. cor-
nuta, is common as a wild shrub from California north to Washington.
This has been used little or not at all in breeding work. A number of
varieties of C. ameruana have been introduced into garden culture
in the East and are being grown by nurserymen. The three best
known are Rush from Pennsylvania, Littlepage from Indiana, and
Winkler from Iowa. Rush has been used extensively in breeding now
hybrid varieties. Littlepage and Winkler have been used to some
extent in this way.
The commercial production of filberts is now an important industry
in the Pacific Northwest, especially in the Willamette Valley of
Oregon and in nearby parts of western Washington. Most of the
varieties are of the species Corylus avellana L., although some are of
C. maxima Mill, and others are apparently hybrids between these
two species. Trees of the former often attain heights of 25 to 30 feet,
and many of those first planted in this country now have trunks fully
18 inches in diameter a foot or so above ground. Those of the latter
are said to attain a height of 30 to 35 feet in Europe and Asia, but no
trees of such size are known in this country. The husks may be
shorter or longer than the nuts, or of the same length. All cultivated
varieties except those of C. maxima parentage have husks that are
open or overlapping at the sides. The husks of C. maxima varieties
NUTS
837
remain tightly closed. The nuts may or may not be naturally dis-
charged free from the husks; varieties of C. avellana vary greatly in this
respect. Typical varieties of C. avellana are Barcelona, Bolwyller,
Du Chilly, Daviana, and Italian Ked. White Aveline is the best
known variety of C. maxima parentage.
Need fok Cross-Pollination
As far as known all varieties of Corylus are self-sterile and must be in-
terplantcd in order to assure effective pollination, a fact that is of rather
recent discovery, although it became
known more than a ceii tury ago that vari-
eties are often made more fruitful by the
application of additional pollen from
other trees to the pistillate flowersof those
having a scarcity of staminate flowers.
This appears to have been the discovery
of George Swayne of England about 1821.
He discussed it at some length in a paper
On the Fertilization of the Female Blos-
soms of Filberts, which he read February
18, 1823. The paper was published the
following year in the Transactions of the
Horticultural Society of London.
In that paper Swayne. told of a series of
experiments begun by him in 1820 and
continued for 3 years. During (he first
year he suspended catkins of the wild
hazel (Corylus avellana) in the tops of
two filbert trees having profuse pistillate
blooms butascarcity or staminate flowers.
The trees had been owned by him for 14
years, during which time there had been
practically no crops. That year, how-
ever, following the application of abun-
dant pollen, the yield was "exactly 2
pounds." With this encouragement he
checked the experiment the following
year by first noting as before t hat the pis-
tillate "flowers were abundant but that
there were practically no staminate flow-
ers. He refrained from adding pollen and
the crop that year was again a practical
failure. The next year, when for the
third time there were many pistillate flowers and few staminates, he
made applications of pollen from the wild hazels to the stigmas of the
garden trees. The crop was again very good, and soon after the har-
vest he reported the results of his 3 years' work.
So far as known, the next investigation of this nature occurred
almost a century later when, in 1917, the late J. F. Jones (fig. 1), of
Lancaster, Pa., sought to hybridize the European varieties of filbert
with the Rush variety of American hazel, Corylus americana (fig.
2, A). He and many others had found the former not commercially
Figure I. — John Franklin Jones
(1871-1928), Lancaster, Pa., in-
troducer of many valuable varie-
ties of nuts. He is believed to
have been first to breed fdberts by
hybridization of species. Begin-
ning in 1917, he sought to cross
European varieties of Corylus
uvellana with the Rush hazel, C.
americana. Being entirely unsuc-
cessful for 2 years, he reversed the
order in 1919 with immediately
favorable results. By this method
he developed the Bixby and Bu-
chanan varieties, which have been
named and introduced since his
death.
838
YEARBOOK, 1937
Corylus varieties
that have been
successfully used in
eastern filbert
breeding:
A, Rush
(C americana), the
pistillate parent
mainly used;
B, Barcelona
(C. aveflana);
C, Rush X
Barcelona,
Iluchanan varietv;
/>, Du Chilly
(C. avellana):
E, Rush X Du
Chilly;
F, Italian Red
(C. avellana);
G, Rush X Italian
Red, Bixby
variety;
H, White Aveline
(C. maxima);
I, Rush X White
Aveline.
Figure 2.
NUTS
839
hardy in the East, and the Bush was the host of the native hazels
that came to his attention. For 2 years he applied Rush pollen to
the pistillate flowers of several European varieties, with negative
results. In 1919 Jones reversed the order and there was a good crop
of nuts. These were planted during the following spring, and from
that time until his death in January 1928, Jones was an active and
enthusiastic filbert breeder. His hybrids came into bearing early,
and by 1924 about 100 were in fruit. By the end of the next 3 years
he had selected 12 to 15 for further observation and eliminated a
considerable number. One that had been numbered 200 proved so
promising that he was seriously
considering its propagation and
introduction to the public. This
Slant was the result of a cross
etween Rush and Italian Red.
It has since been named Bixby
(fig. 2, G) after the late Wilkr'd
G. Bixby, of Baldwin, N. Y., a
friend and coworker of Jones.
Another plant, no. 92, greatly
resembling Bixby, but shown by
Jones' record to be a Rush X
Barcelona cross, has been named
Buchanan (fig. 2, (J) and is being
propagated for the nursery trade.
Both Bixby and Buchanan arc
apparently of considerable prom-
ise for home planting in (lie East.
European Filberts in the
Eastern Unitei> States
In the aggregate there has been
a large amount of selection work
with the filbert in this country
during the past century or more.
Plantings of European varieties
and seedlings have been made fre-
quently in various sections.
Most of the better varieties and seedlings were introductions made
during the eighties and nineties by the late Felix Gillet (fig. 3), a
Frenchman who established a nursery at Nevada City, Calif., in 1871.
A good many introductions have been made by others, so that alto-
gether several hundred varieties and seedlings from Europe have been
tried out in this country. The best of these have proved commer-
cially profitable only in the Pacific Northwest. They have been suc-
cessful in the East to a limited degree and as a rule only when grown
in situations well protected from extremes of temperature, as by a large
body of water, a building, a hill, or a group of trees.
Three known factors stand in the way of success with the European
varieties of filbert in the East. The most important is a serious
blight, Cryptosporella anomala (Pk.) Sacc, which causes little injury
to the native species but spreads quickly and with fatal results to
Figure 3.— Felix Gillet (1835-1908), pro-
prictor of Darren Hill Nurseries, which he
established at Nevada City, Calif., in 1871.
lie was one of the most outstanding figures
of his time in introducing carefully selected
varieties of filbert, Persian walnut, and
chestnut from Europe.
840
YEARBOOK, 1937
European varieties planted in the vicinity. The likelihood of serious
losses by this disease has decreased greatly during the last half century
with the more or less general eradication of the native hazel plants on
roadsides and fence rows, incident to clearing the land. However,
the disease is still a grave menace whenever either European varieties
or the new hybrids (Corylus americana X avellana) are planted near
native species growing wild.
The second factor is lack of hardiness. Most European varieties of
filberts are subject to winter injury, which may kill only the staminate
flowers, or the pistillate ones, or
both, or it may kill the tree tops,
or even the tree trunks to the
ground. As a rule, however, only
the flowering parts are injured.
The tlrird factor is self-sterility.
So far as known all varieties are
largely, if not entirely, dependent
upon other varieties for effective
pollination. Until recent years
most plantings in the East were
made without regard to pollina-
tion requirements.
Some of the men who were
most active in the introduction
and early testing of varieties of
filberts in the Pacific Northwest
were A. A. Quarnberg (fig. 4),
Vancouver, Wash.; Thomas
Prince, Dundee, Oreg.; and
George A. Dorris, Springfield,
Oreg. Among those most recent-
ly active in the field of selecting
and testing new varieties are
Pearcy Bros., Salem, Oreg.; H.A.
Henneman, Portland, Oreg.; A.
M. Gray, Milwaukie, Oreg.; W.
A. Schmidt, Corvallis, Oreg.;
A. B. Scherf, Newberg, Oreg.;
and D. Fitzgerald, Washougal,
Wash. These men procured their trees mainly from Gillet, but to
some extent they made direct importations. Among those in the East
who have contributed most to filbert culture since the early eighties
may be mentioned the United States Department of Agriculture; the
New York State Agricultural Experiment Station at Geneva; A. S.
Fuller, Ridgewood,N. J.; J. W.Kerr, Denton, Md.; Conrad Vollertsen,
Rochester, N. Y.; Robert T. Morris, Stamford, Conn.; W. G. Bixby,
Baldwin, N. Y.; and J. F. Jones, Lancaster, Pa. Vollertsen brought a
number of varieties from Germany in 1912. Of these, Italian Red (fig.
2, F) is the only one now in special favor among eastern planters.
Dr. Morris introduced a valuable seedling from Bohemia, which he
later named Bonybush. The other men named in this group made
their contributions by testing varieties in their respective localities.
Figure 4.— A. A. Quarnberg (1849-1933),
Vancouver, Wash., one of the leading figures
in laying the foundation of both the filbert
and Persian walnut industries in the Pacific
Northwest. He was one of the first to plant
and test most of the varieties now of lead-
ing importance in that part of the country.
NUTS 841
Raw Material for Filbert Breeding
Most filbert varieties of either American or European production
are without conspicuous merit. As previously noted, few are both
hardy and fruitful except in specially favorable environment. Most
filberts are of medium palatability and the nuts of many varieties are
often imperfectly developed and the kernels thickly coated with coarse
fiber. Some varieties are poor bearers, or the nuts may be too small
or too thick-shelled .to be acceptable on the market. Many are
difficult to extract from the husks, and some produce only small
quantities of pollen.
Some varieties are very good in quality and flavor. The nuts of
some are of good size and thin-shelled. The kernels are often plump
and bright-colored. The best nuts are entirely free from coarse cover-
ing over the kernel. However, some of the finest are too small for
commercial use. White Aveline (fig. 2, H) is typical of the mixture
of good and bad characteristics found in filberts. In quality of
kernel it is one of the finest varieties known. It also has a remark-
ably thin shell; but, since it belongs to the species Corylus maxima, it
has a long, tubular, tightly closed husk, which fails to open at maturity,
and husking is difficult.
The variety with the greatest number of good points now grown in
this country is Barcelona (fig. 2, B), which was introduced from Europe
by Gillet probably during the seventies or early eighties. The tree is
a vigorous grower and a good bearer; the nuts ripen early and within
a short period and readily fall free of the husk. They are attractive
in appearance and of large size. The shells are of medium thickness,
and the kernels are usually plump, clean, quite sweet, of fine texture,
and fairly rich. The nuts are roundish in form, although variably so.
The kernels are not so clean or free from covering over the pellicle as
some others, nor are they the best in flavor. Nevertheless, every-
thing considered, commercial growers of the Willamette Valley, Oreg.,
have thus far found this to be their most profitable sort.
The second leading variety in the Pacific Northwest is Du Chilly
(fig. 2, D), also an early European introduction made by Gillet. As
compared with Barcelona it is moderately vigorous, not as productive,
and less'hardy. The nuts do not mature quite so early, and only a
small proportion are naturally separated from the husks, although they
are not difficult to husk. The nuts are oblong and flattened instead
of being roundish. The shell is about as thick as that of Barcelona.
The kernel is similar in plumpness and about equally free from fibrous
covering. It is slightly sweeter and more palatable than Barcelona.
Du Chilly nuts bring a somewhat higher price in the market, which
largely, if not entirely, offsets the lighter fruiting of the variety. Both
Du Chilly and Barcelona are less inclined to throw up suckers per-
sistently about the base of the tree than are some others.
Daviana is the best known of the large varieties from Europe, which
are notably thin-shelled. It is an excellent pollinizer for other varie-
ties, but is itself a shy bearer, is very subject to injury by a bud mite,
and frequently the kernels are not plump. From the standpoint of
the breeder, its chief advantages are believed to be thinness of shell and
its value as a pollinizer.
138904°— 37 54
842 YEARBOOK, 1937
Nature of the Problems Involved
The problems involved in filbert breeding are relatively simple as
compared with those of the chestnut, since there is already ample
material. The area in the Pacific Northwest within which commercial
filbert growing is centered is relatively small and has many full collec-
tions of varieties. In the East species and varieties now thought
essential are represented in collections of the Bureau of Plant Industry,
United States Department of Agriculture, near Washington, D. C,
and of the New York State Agricultural Experiment Station at Geneva.
Breeding by hybridization has made much headway at each place.
Also a valuable collection of first-generation hybrids between Rush,
one of the best-known native varieties of Corylus americana, and cer-
tain leading European sorts, mainly of C. avellana, is under observa-
tion at the J. F. Jones Nurseries, Lancaster, Pa.
Present Breeding Work and Future Possibilities
The most promising line of attack for the breeder in the East seems
to be a continuation and expansion of breeding by hybridization, such
as is already under way, rather than by making further selections
from European varieties or the native species, both of which generally
fall below the standards of American growers or consumers. Until
superior hardy varieties can be developed, the best of the American
varieties are likely to be used to a limited extent for home planting in
zones beyond the climatic limits of safety for hybrids or European
varieties.
In the Pacific Northwest the problem of the breeder is to develop
more perfect varieties, chiefly from seedlings of Corylus avellana.
The problem of hardiness is less acute than in the East. A desirable
variety in the Northwest would be one that is resistant to fungus
diseases and insect pests, a strong grower, either self-fertile, or a good
?ollinizer for other varieties, and a heavy annual bearer of choice nuts.
lhe nuts should mature early and all at one time ; they should separate
naturally from the husks; they should be bright-colored, uniform in
size, and probably oblong rather than rounded for greater appeal to
the consumer. The shells should be thin enough to be broken easily,
and the kernels should be plump, clean, bright, sweet, and of fine
texture. In the appendix will be found a list of breeders engaged in
work with the filbert, and of varieties considered promising for breeding
work.
On the western coast filbert breeding is still largely carried on by
mass selection. Out of the thousands of seedlings that are being
grown and tested by private growlers, the best finally come under
critical observation when all but an extremely small percentage are
rejected. Few varieties have yet come to light that meet the dual
requirement of commercial crop production and pollination of other
varieties. When breeding reaches the point of seeking greater hardi-
ness in order to widen the western range of successful production, it
is not improbable that the wild species, Corylus calij 'ornica, of that
region will be given a trial as one of the parents, in the same way that
G americana has been used successfully in the East. Thus far, pollen
of neither of these native species has been found to function on the
NUTS 843
pistillate flowers of European varieties, but as the eastern species has
been useful as a pistillate parent, the same may prove true with the
western one.
Filbert breeding, both by selection and by hybridization, is in prog-
ress at a number of points in the East. The United States Bureau of
Plant Industry has made important contributions in its studies of
varietal values not only in that part of the country but also in the
Pacific Northwest, It has also made a number of important introduc-
tions of varieties from Europe. It is continuing its studies of the merit
of European varieties both at the Arlington Experiment Farm, Arling-
ton, Va., and at the United States Horticult\iral Station, Beltsville,
Md. The work at the latter place is now largely confined to testing
first-generation hybrids resulting from crosses made by its staff on the
grounds of the late W. G. Bixby, Baldwin, N. Y. The pistillate parents
used in making these crosses were Rtish, Littlepage, and Winkler
varieties of Corylus americana as well as a number of varieties of
C. avellana and C. maxima. Among others used as pollen parents were
G. colurna, the Turkish tree hazel, and C. heterophylla Fisch., from
eastern Asia, sometimes called the "various-leaved hazel." Alto-
gether, there are now at the Beltsville station about 2,000 hybrid plants
of bearing age, transplanted from the nursery from 1932 to 1936.
Several of those that have fruited appear highly promising for home
use. Nuts of the first generation are a little small for sale in the
unshelled condition.
Hybridization of filberts at the New York (State) Agricultural
Experiment Station was begun in 1930. In 1933, 535 hybrid plants
resulting from crosses made by Federal workers were transferred to
Geneva from the Bixby grounds at Baldwin, N. Y. Some of these
now in bearing are exceedingly promising. In addition to these plants
there are 352 other plants at Geneva resulting from more recent crosses
made by station workers. Climatic conditions at Geneva seem to be
more favorable for varieties of Corylus avellana than at either of the
Federal stations, but partial or complete crop failures are not in-
frequent even there.
The Virginia Agricultural Experiment Station at Blacksburg began
selective breeding from Kentish Cob seedlings in 1921. The purpose
has been to develop hardy varieties of merit for use in that State. One
seedling has been selected as worthy of further observation.
The Minnesota Agricultural Experiment Station at University
Farm, St. Paul, is breeding by selection from native plants of Corylus
americana for the purpose of developing hardy varieties of value in
that State for home planting. About 200 plants have been brought to
fruiting and discai'ded. Nine hundred more are now under observa-
tion, of which some appear to have considerable promise.
Working privately, S. H. Graham, Ithaca, N. Y., is doing consider-
able filbert breeding, mainly by selection. However, he has brought
into fruit a number of second-generation hybrids of the crosses made by
the late J. F. Jones, Lancaster, Pa. From these he has made one or
two selections of considerable promise.
E. M. Ten Eyck, South Plainfield, N. J., has had for many years a
number of Corylus avellana seedlings grown from nuts bought on the
market. These have been injured very little by winter temperatures,
844 YEARBOOK, 1937
have borne well, and the nuts have been quite satisfactory for home
use. C. P. Close and J. J. T. Graham, of the United States Depart-
ment of Agriculture, have both grown for many years a considerable
number of seedlings of C. avellxma from which it now seems possible
to make selections^ of value for home planting. The trees of Close
are at his home in College Park, Md., and those of Graham at
Glenn Dale, Md.
The J. F. Jones Nursery, Lancaster, Pa., is now fruiting and con-
tinuing under test about 50 first-generation hybrids from crosses
made by Jones. As already noted, two of these have been given
variety names and are being propagated commercially. While it is
improbable that further selections will be made for production varie-
ties, it is possible that some of this collection will be found useful as
pollinizers.
There is a large 24-year-old Barcelona tree on the premises of C. A.
Reed, Takoma Park, Md., which bore a full crop for the first time in
1936, although it has bloomed freely with great regularity. Appar-
ently it was effectively pollinated in the spring of 1936 by pollen
from first-generation Eush X Barcelona hybrids nearby. If further
investigation should prove that a Rush X Barcelona hybrid will
effectively pollinate Barcelona, which is both self-sterile and sterile to
Rush and to all other varieties of Corylus americana, the result will
be extremely interesting as well as significant. If such hybrids can
be used as pollinizers for Barcelona and other European varieties
whose staminate flowers are easily killed by winter temperatures,
the successful cultural range of such varieties might be considerably
widened.
Progress already made in the improvement of filbert varieties by
hybridization indicates great future possibilities for this kind of work.
It should be possible within a reasonable period to develop superior
varieties for commercial growing in the Pacific Northwest with which
to meet the requirements of American markets now largely supplied
by imports. Eastern varieties of high merit should be developed for
home planting over much of the region from lower New England and
the Great Lakes on the north to perhaps the Potomac and Arkansas
Rivers on the south. No doubt much of Wisconsin, southern Minne-
sota, South Dakota, and Nebraska might also be included.
THE HICKORY GROUP
The hickories form an important group of trees valuable for the pro-
duction of both nuts and timber. With the exception of a single
species, Hicoria cathayensis Sarg., from southeastern China, the entire
genus is strictly American. The hickory range extends from the
Provinces of Quebec and Ontario in Canada across the eastern and
central United States into northern Mexico. Fifteen species are
described by Sargent in the Manual of the Trees of North America.
Of these only three or four produce nuts of particular value, although
the nuts of certain others are edible in varying degrees.
From the standpoint of value of nuts the pecan, Hicoria pecan
(Marsh.) Britton, is the most important member of the group. In
crop value it rivals the Persian (English) walnut of the western coast.
The tree is one of the largest east of the Rocky Mountains. Broadly
NUTS 845
speaking, the natural and cultivated range of the pecan covers the
Cotton Belt and lower elevations northward in the Mississippi Valley
into Indiana, Illinois, Iowa, and southeastern Kansas.
The pecan tree is valuable in ornamental planting wherever climatic
and soil conditions are favorable. It sometimes succeeds as far north
as Connecticut, but nut production is unimportant north of the District
of Columbia or the latitude of Torre Haute, Ind.
Other hickories offering inducement to breeders include the shag-
bark, Ilworia ovata (Mill.) Britton, the shellbark, II. laciniosa (Michx.
f.) Sarg., and a number of other species of less importance, as well as
various hybrid forms that occur with considerable frequency in nature.
The shagbark is much the most valuablo nut producer. Nuts of the
shellbark, while large and alluring, are often poorly filled.
Breeding to improve hickories of any species has thus far largely
been confined to selective methods. By such means a very consider-
able number of varieties of both pecan and others have been brought
to light. Breeding by hybridization has been under way with
the pecan for many years, but so far without the introduction of
many varieties. This form of breeding has not yet been under-
taken in earnest with other hickories.
Pecan
According to dates given by Taylor (38), pecan selection is known
to have begun as early as 1846 or 1847, when scions of a variety later
named Centennial were successfully grafted by a Louisiana slave
named Antoine. The next variety known to have been grafted was
Van Deman, in 1877, although it was not permanently named until
15 years later. The Rome variety was first propagated in 1882,
Hollis in 1884, Frotscher in 1885, Stuart in 1886, and Pabst in 1890.
The first pecan nursery was that of William Nelson, New Orleans,
La., who began selling seedlings in 1874 and grafted trees in 1879.
The period of greatest activity in the introduction of new varieties
was probably between 1905 and 1925. During that time practically
every important pecan center of the entire South introduced its
favorite varieties of local origin.
The first carlot shipment of pecan nuts of named varieties, carefully
graded according to definite standards of size and quality, is believed
to have been made in 1917 by J. M. Patterson, president of the
Georgia Papershell Pecan Growers' Association, Putney, Ga. By
1920 there was a great multitude of varieties in bearing, and nuts of
the same size and general character, whether from seedling trees or
named varieties, brought about the same price. This caused the selling
agencies to begin marketing a large portion of the crop by brand instead
of by variety as had been done until that time. Now, with the
exception of a few varieties, such as Schley and Stuart, most of the
pecan crop, no matter whether from cultivated or wild trees, is graded
according to size, form, appearance, and to some extent thinness of
shell and general merit. High uniformity, possible only when varieties
are sold separately, has largely disappeared, at least for the time being.
The loss of varietal status, insofar as selling pecans is concerned,
has been partially due to the failure of a good many varieties to meet
the requirements of successful production and marketing, and of any
846
YEARBOOK, 193 7
varieties to become outstanding. Light bearing, uncertain filling,
variability in size of nuts from year to year, even from the same trees,
together with susceptibility to insect pests and fungus diseases, have
had much to do with a situation that has practically compelled the
blending of the nuts of the different varieties together instead of
selling them separately. A process of readjustment is now taking
place throughout the entire field
of production and will probably
continue until a majority of pres-
ent varieties have been superseded
by new kinds better suited to the
requirements of the orchard and
the market. Future plantings
will doubtless be established with
superior varieties now unknown,
and with greater consideration of
environmental and cultural re-
quirements.
Past Breeding Work With Pecans
Apparently the first breeder of
pecans by hybridization was
Forkert (13), of Ocean Springs,
Miss., who began this work in
1903. He was followed 1 year
later by Risien {29), of San Saba,
Tex. Both men were of foreign
birth, Forkert having been born
in Germany and Risien in Eng-
land. They spent much time in
searching for the best varieties
obtainable by selection from seed-
lings before undertaking the work
of hybridization. Forkert found
no chance seedlings that he thought worthy of introduction, but Risien
introduced several varieties selected from wild seedlings.
Forkert's first introduction, Dependable, was the result of a Jew-
ettX Success cross. This proved disappointing and has since been
practically abandoned. Admirable, a Russell X Success hybrid, also
was a disappointment insofar as being an improvement over existing
varieties was concerned. His one apparently meritorious introduc-
tion is Desirable, a variety of unknown parentage. It was not widely
disseminated previous to his death in 1928, and would doubtless have
been lost had it not been for scions that he sent to the United States
Pecan Field Station near Albany, Ga., in 1925. From this stock the
variety has been widely disseminated for test planting.
The work of Risien (fig. 5) was in a semiarid region at high altitude
in western Texas. He seems to have been the first in the South to
conduct a systematic survey of wild pecans for seedlings worthy of
propagation as new varieties. About 1882 (SO) he discovered the
parent tree of the variety that he later named San Saba. He was
probably the first to plant nuts from a selected tree in orchard form
Figure 5. — E. E. Risien, San Saba, Tex., a
pioneer in propagation and varietal im-
provement of the pecan by selection and
hybridization. A majority of the most
popular varieties of Texas are among his
productions.
NUTS 847
for the purpose of growing seedlings from which to make selections.
A great many persons planted seedling trees for nut production during
that early period because grafted trees were unavailable, and from
such trees many good selections were made later. Risien planted
chiefly for the purpose of originating valuable varieties, and in this
he was successful.
Risien independently mastered the art of propagating pecan trees
during the early nineties, and while he was a half century behind
Antoine in this work, so far as is known he was the first propagator in
Texas, and so far as he knew he was the pioneer in the field. He
was the first in the South to top-work large pecan trees. In addition
to San Saba, he introduced Attwater, Kincaid, and Sloan as selections
from wild seedlings. Among the selections from his orchard of 1,000
San Saba seedlings are Colorado, Jersey, Libertybond, Onliwon, San
Saba Improved, Sovereign (Texas Prolific), Squirrels Delight, Supreme,
and "Western (Western Schley). Among varieties from definite
crosses are Banquet (Sovereign X Attwater), Commonwealth (Long-
fellow X Sovereign), Kincaid Improved (Onliwon X Kincaid), Sloan
Improved (San Saba X Sloan), and Venus (San Saba X Attwater). A
recent introduction is Garner (John Garner), an open-pollinated
seedling of San Saba Improved.
Another Texan who has contributed much to the pecan industry,
not only in his native State but also in the entire South, is J. fi.
Burkett, of Clyde, Tex., for many years chief of the division of edible
nuts in the State department of agriculture at Austin, and author
of several bulletins on pecan culture. Burkett was the discoverer
and introducer of the valuable Burkett variety, which has a large,
round nut with very thin shell and excellent kernel characteristics.
It has long been a favorite among planters from western Texas to
the Pacific coast. It has several features that should make it desir-
able for use in breeding work.
Other planters in many States, covering practically the entire South,
established seedling pecan orchards having from a few hundred up to
several thousand trees. One such orchard, planted in 1897 by James
(17), of Mound, La., later became the source of such important varie-
ties as Carman, James, and Moneymaker. During approximately 30
years, beginning in 1880, seedling orchards and dooryard trees on the
Gulf coast of Mississippi, especially in the vicinity of Ocean Springs and
Pascagoula, became fruitful sources of new varieties. It was then that
Alley, Delmas, Pabst, Russell, Schley, Stuart, Success, and many
others less prominent were introduced from that section. Among per-
sons most active in the introduction of these varieties were Theodore
Bechtel, C. E. Pabst, and W. R. Stuart, of Ocean Springs, and A. G.
Delmas, I. P. Delmas, and F. H. Lewis, of Pascagoula.
In northwestern Florida during the nineties, seedlings grown from
nuts of trees owned by Arthur Brown, Bagdad, Fla., had an impor-
tant part in giving rise to varieties in that region. An orchard planted
with such stock in 1886 by J. B. Curtis at Orange Heights, Fla.,
became the source of the Curtis variety in 1896, and of Hume, Ken-
nedy, and Randall somewhat later. Many other Florida varieties,
less well known, are believed also to have originated as seedlings of the
Arthur Brown stock.
848 YEARBOOK, 1937
Probably the first large-scale breeding of pecans by hybridization
was begun by the United States Bureau of Plant Industry in 1915
in the orchard of C. E. Pabst, Ocean Springs, Miss. Hundreds
of crosses were made that year and the next, and the resulting
nuts were planted on the grounds of Pabst. However, with the
entrance of the United States into the World War the work was
discontinued and the young trees were neglected. Pabst died in
1919, and with the change in ownership of the property the entire lot
was lost.
This work was resumed in 1920 in the orchard of B. W. Stone,
Thomasville, Ga., and continued for several years. The first nuts
were planted on the grounds of the Georgia Experiment Station,
Experiment, Ga. Of these, a Schley X Moneymaker hybrid is now
believed to have considerable promise. In 1922 the United States
Pecan Field Station at Philema, Ga., was established, and several
thousand young hybrid trees were soon developed. In 1930 the
youngest trees were transferred to the United States Pecan Field
Station at Kobson, La. A considerable number of trees at the former
station have been in bearing for several years and are now being
observed closely with regard to bearing habits, disease resistance,
and merits of nuts. Some of these hybrids are highly promising but
require considerable further observation.
In the North, where the native pecans are mostly small and difficult
to crack but otherwise much like those of thp Southeast, the first
recorded steps toward selecting varieties began during the early
nineties, when the Department of Agriculture received nuts from
Illinois, selected mainly because of their superior size. One of the
first trees to attact attention in this way belonged to H. G. Hodge,
York, 111. During the next few years this variety came to be known
as Hodge's Favorite or Illinois Mammoth, and many nuts from the
original tree were sold for seed purposes. It was accorded varietal
recognition by Taylor (38) in 1908, who called it Hodge.
The second northern pecan variety to be recognized appears to have
been Major, discovered by W. N. Roper, Petersburg, Va., about 1907.
His attention was attracted to the superiority of certain nuts in a
mixed shipment that he procured for seed purposes from a merchant
in southern Indiana. By persistent efforts Roper traced the nuts to
the parent tree near Green River in northern Kentucky, some 15
miles southeast of Evansville, Ind.
The next step toward bringing out new northern varieties seems to
have been made in 1908, when a pecan contest was held at Mount
Vernon, Ind., under the direction of the Purdue University Agricul-
tural Experiment Station. It was then that Warrick, now practically
obsolete, was brought to light.
During the period of 1910 to 1915, Simpson Bros., Mason J. Niblack,
and W. C. Reed, Vincennes, Ind.; J. F. Wilkinson, Rockport, Ind.;
and Thomas P. Littlepage, a native of the Rockport region but then a
resident of Washington, D. C, spent much time, labor, and money
in searching for other worthy varieties. It was during this period that
Busseron, Butterick, Greenriver, Indiana, Kentucky, and Posey were
recognized and introduced. From then until quite recent years very
few other northern sorts have come to notice. However, beginning
NUTS 849
in 1933 and continuing annually since, a pecan contest has been held
in New Haven, 111., under the direction of H. C. Neville, formerly
farm adviser of Gallatin Cmmty. As a result of these contests
several highly promising varieties have come to light, but they have
not yet been offered by nurserymen. In 1934 a nut contest conducted
by the Northern Nut Growers' Association brought out several
apparently desirable new varieties, which ought not to be lost. Pres-
ent-day breeders of pecans are listed in the appendix.
Problems in Pecan Breeding
The known defects of present varieties of pecan are many, regardless
of the reputation the species justly enjoys of being one of the finest of
table nuts. In the orchard many varieties are seriously susceptible to
attack by insect pests and diseases of various kinds. Other defects
include shy bearing; late ripening; weak crotches, which split badly;
wood that breaks under the weight of nuts, especially late in summer
(hiring storms; poor sbelling characteristics; failure to fill well; lack of
good flavor; and a tendency of the nuts to germinate before dropping,
from the trees, when dry summer weather is followed by wet periods
late in the growing season.
Pecans reach the consumer in two forms, shelled and unshelled.
The kernels are known in the trade as shelled nuts, and by far the
greater portion of the crop is marketed in this form. Nuts of smaJl and
medium sizes from either the forests or orchards arc sold as "halves" or
"pieces." Pecan halves are used as salted and roasted nuts and in
capping such products as cakes, breads, and candies. Pieces are
used as an ingredient in pastry, ice cream, and confections. For
capping, the smaller the halves the better, since this means a larger
number per pound. Seven hundred per pound is usually the minimum
required.
When the cultivated crop is of bumper proportions or offgrade for
any reason, so that prices are inclined to drop, many of the nuts are
diverted from the unshelled to the shelled market. Prices for culti-
vated varieties, once 10 to 50 times as great as for the medium to
small nuts from the forest, are now only 2 to 5 times as great. The
best prices now being received by growers for cultivated pecans is
about one-fifth of what it was two decades or more ago when the great
majority of the present varieties were discovered and introduced.
In the present economic status of the pecan industry the most
profitable varieties are those that are the most productive largely
without regard to other qualities. Fruitfulness, therefore, is the
characteristic sought above all others, often to the exclusion of other
important factors, particularly quality and flavor.
Some of the choicest pecan varieties, from the standpoint of the nuts
alone, are no longer being planted because of extreme susceptibility
to fungus diseases, failure to bear well, or deficiencies of kernel.
Often these weaknesses are aggravated by unfavorable environmental
conditions such as severity of climate, poverty of soil, or too close
planting. For these reasons it is impossible to attribute the failure of
any given variety to any single factor or to any particular combina-
tion of factors. It is equally impossible at this time to predict with
certainty the commercial requirements for varieties in the future.
850 YEARBOOK, 1937
However, it seems to be a reasonable assumption that pecans will be
marketed more and more in the shelled condition, and varieties must
be developed with this requirement in view. Present varieties can,
in many cases, be made to give more satisfactory results by improving
cultural practices according to knowledge now available.
Desirable combinations of nut characters are to be found in a good
many varieties. In the nursery and orchard such points as ease of
propagation, rapid growth, precocity, productiveness, and resistance
to disease are all to be found, distributed variously among the different
varieties but not in perfect combination in any. For example, well-
grown nuts of the Schley variety have good size, handsome appearance,
suitable form for shelling by hand or machine, very thin shells, good
shelling quality, and superior kernel characteristics. The variety is
easy to propagate, is a rapid grower, and forms a symmetrical tree.
It begins bearing at a relatively early age and normally is fairly pro-
ductive. However, the susceptibility of Schley to scab makes it un-
desirable for commercial orchard use. Another example is Money-
maker, which is easy to propagate, a rapid grower, precocious, prolific,
and early in ripening. On the other hand, the nuts are roundish in
form, variable in size, not especially thin-shelled, not easy to shell by
hand, and medium in quality and flavor of kernel. In appearance
the nuts are only moderately attractive, and the tree is so susceptible
to certain leaf diseases that it is no longer in favor with leading growers.
Three well-known eastern pecan varieties having outstanding points,
which should be useful in breeding, are Curtis, Moore, and Stuart.
Curtis nuts are among the best of any variety to eat out of hand.
They are a little small but quite thin-shelled and easily cracked, and
the kernels are very fine, being plump, rich in quality, and un-
usually sweet. Moore is one of the most prolific bearers and the nuts
ripen with the earliest. Stuart is probably the most dependable
variety in the Southeast. While it is not a heavy bearer, in most
localities it performs consistently and the nuts are large, attractive in
appearance, and uniform in size.
Among varieties of the western group, Burkett, Halbert, and Sover-
eign are well known and probably as useful for breeding purposes as
any. All begin bearing at an early age and increase in productivity
rapidly. The shells of Burkett and Halbert are remarkably thin.
The kernels of all are plump, bright-colored, and distinctly superior
to those of most other varieties.
The problem of improving pecan varieties by breeding is greatly
affected by the uncertainty as to future market requirements. With
few exceptions past efforts have been to develop varieties for the un-
shelled market. For this purpose, large size has been one of the prin-
cipal assets. Two small varieties, the Candy, by Theodore Bechtel,
of Ocean Springs, Miss., and the Keuss, by G. B. Keuss, of Hohen
Solms, La., were introduced at about the same time many years ago
for sale in the shelled trade. These nuts were unusually thin-shelled
and of excellent shelling and kernel qualities. The parent trees in
both cases were heavy bearers, but neither variety met with favor on
the part of nurserymen or planters on account of the small size of the
nuts. However, the nuts of neither were small enough to meet the
present market requirement of more than 700 halves to the pound,
NUTS 851
and it is an open question as to whether either would be of particular
value in breeding to develop smallness in size. Probably the only
varieties that can meet this requirement are a few recently brought
to attention in some of the Northern States but not yet well tested.
Growers as a class prefer not to produce pecans of small size. In
fact it is doubtful whether it would be profitable for them to do so at
the present time. The question is to what extent, if any, it would
pay to raise pecans exclusively for the shelled market. The demand
ill that direction is usually well supplied with pecans from the forests
or those from the cultivated orchards that might be classed as imper-
fect or surplus pecans. It may be that, with the exception of the
peanut, which strictly speaking is not a true nut, none of the Ameri-
can-grown nuts can compete on a price basis in the retail market for
shelled nuts with certain foreign species that are produced at much
lower labor costs. It is certain, however, that very large pecans no
longer sell readily to discriminating consumers. It is also true that
greater portions of the crops from orchard trees are steadily finding
their way into the shelled market. It would be very desirable, if
possible, to determine the probable future market requirements as
to size. In the absence of a basis for an accurate prediction as to
what the future may bring forth in this direction, it will probably be
well to follow the present trend, which is definitely toward nuts of
medium size. The largest nuts from these crops can be separated
out by sizing machines and sold in the increasingly more limited
market willing to pay a premium for such sizes.
The best pecan varieties lack certain characteristics necessary to
make them ideal. New varieties with all the features of an ideal nut
are not to be expected until a planned program of breeding to accom-
plish certain definite ends is carried out. Such a program would
involve the growing of a large number of second-generation hybrids
from the best breeding stock. In this way alone will it be possible
to develop material from which to select varieties resistant to disease
and superior in other characteristics. Cytological analyses of varie-
ties may be expected to yield information as to their value as breeding
stock and to throw light on problems of pollen viability and sterility.
Present Breeding Work and ils Aims
Pecan breeding as it has long been carried on by the Bureau of
Plant Industry has for its objectives improvement along seven dis-
tinct lines. These are (1) hardiness, (2) disease resistance, (3) fruit-
fulness, (4) size of nut, (5) shell thinness, (6) shelling quality, and
(7) kernel quality. The purpose is to develop good varieties that
can be grown with profit in each of the three distinct natural pecan
districts, southeastern, southwestern, and northern. The south-
eastern district extends from the South Atlantic seacoast west to
central Texas. The southwestern district includes localities wherever
the pecan succeeds from Fort Worth, Tex., west to Arizona and
southern California. The northern district includes all localities
suitable for pecan growing in. the Mississippi Valley north of the lati-
tude of Memphis, Tenn., and in the Coastal Plain or lower Piedmont
regions in Virginia and northward.
852 YEARBOOK, 1937
No great amount of pecan breeding has yet been undertaken by
State experiment stations. In cooperation with the Bureau of Plant
Industry, the Georgia Experiment Station grew to fruiting several
hundred seedling trees resulting from crosses made by Bureau workers
at Thomasville, Ga. From these the station workers selected for
further observation one designated as A-93, a Schley X Moneymaker
hybrid. This is a strong-growing, fruitful tree producing nuts of
considerable excellence.
The North Carolina Agricultural Experiment Station began breed-
ing pecans at Willard, N. C., in 1912. From a large number of
seedlings of named varieties station workershave selected a Schley
seedling, RT-6-4, as being of much promise. The New Mexico
Agricultural Experiment Station at State College, N. Mex., has made
one selection from seedlings of named varieties. This is designated
as College No. 1. It grew from a Sovereign nut that had been open-
pollinated.
A certain amount of pecan breeding has been started in two foreign
countries. The Department of Agriculture of New South Wales is
doing preliminary breeding at the Breeding Station, Grafton Experi-
mental Farms, Sydney, Australia. Selective breeding is under way
in Mexico under the direction of the Secretariat of Agriculture, Depart-
ment of Stations and Experimental Fields, Mexico, D. F.
Three different sets of pecan varieties are required to meet environ-
mental conditions in the respective American regions. Greater hardi-
ness is being sought in order that varieties may be used for planting
north of the present limits and to safeguard more southern plantings
against extremes of cold. Resistance to disease is one of the most
vital points for the success of any variety. Many otherwise good
varieties have had to be abandoned because of their susceptibility
to fungus diseases. No factor is more important than that of pro-
ductiveness. It makes little difference how worthy a variety may be
in other respects — if it does not bear well it must be replaced sooner
or later. By good nut size is meant medium rather than large.
Overlarge nuts are objectionable because of the tendency to develop
imperfect kernels. Pecans that will average 60 to 70 to the pound are
most desired in the unshelled market. Thinness of shell and ease of
shelling are also being sought after, as without these characters pecans
in the shell are unlikely to compete successfully with nuts of other
kinds that can easily be shelled in the hands or that are sold only in
the shelled condition. Varieties of pecan of probable value for breed-
ing are listed in the appendix.
Hickories Other Than Pecans
Selections from species of hickory other than pecan have resulted
in the naming of a large number of varieties. Relatively few have
been propagated by nurserymen and none has been planted in com-
mercial orchards. A considerable number have been top-worked on
trees of bearing age, and a few, grown as nursery trees, have been
established in small test orchards.
Improvement of the hickories by selection was strongly urged as
early as 1855 in an article by S. Hale, Keene, N. H., in The Magazine
of Horticulture, in March of that year. The earliest record of hickory
NUTS
853
selection appears even before that, as the "Perkiomen Shellbark"
was brought to light in October 1853, when Abraham "Wismer, of
Perkiomen Township, Montgomery County, Pa., exhibited nuts of
this seedling as "a large variety with thin shell and kernel of best
quality." There is no record that this "variety" was ever propagated
by budding or grafting, and it may be assumed that it is now lost.
The next northern hickory to
receive varietal recognition seems
to have been the so-called Hales
Papershell, a thin-shelled variety
of shagbark discovered by Henry
Hales, of Ridgewood, N. J., first
recorded by A. S. Fuller in 1870
and first propagated by J. R.
Trumpy, of Parsons & Son, nurs-
erymen of Flushing, N. Y., about
1880. This variety was propa-
gated to a limited extent and
widely disseminated throughout
the East over a period of many
years. It is now practically
obsolete.
The next varieties to receive
recognition grew from nuts plant-
ed in 1885 by J. W. Kerr, Denton,
Md. Kerr sent away for "shell-
bark" seed nuts, which he planted
along the roadways of his farm.
From the resulting trees he se-
lected a number of seedlings to
which he gave varietal names.
He grafted some of these on his
home grounds, but so far as known
none was established elsewhere
and none is now believed to be
in existence.
Varietal names were used for
luckories in the annual report for
1891 of H. E. Van Deman, po-
liguie (>. — Kobert Tuttle Morris, Stamford,
Conn., who has contributed much to the
published knowledge of species and varieties
of native nuts in the Northeastern States.
In 1905, 1906, and 1907 he conducted
annual contests for the best walnuts and
hickories. He became charter president of
the Northern Nut Growers' Association,
founded in 1910. He has written many
articles and one book pertaining to various
phases of nut culture, especially propagation.
mologist of the United States
Department of Agriculture. He described Learning, from Rush G.
Learning, Sedalia, Mo. ; Milford, from O. C. Cook, Miliord, Mass.; and
Shimar, from Samuel C. Moon, Morrisville, Pa. In 1892 A. J. Coe,
Meriden, Conn., offered a prize for the best hickory that might be
submitted to the Connecticut Agricultural Society. The prize went
to Whitney Elliot, of North Haven, Conn., for a variety named
Elliot in his honor.
To Robert T. Morris (fig. 6), formerly a leading surgeon of New
York, N. Y., but now retired and living at Stamford, Conn., belongs
credit for beginning a movement in 1905 by which the majority of
the varieties of hickory now known have been brought to notice. In
that year he inaugurated a series of northern nut contests in which
854 YEARBOOK, 1937
cash prizes were given for the best nuts from seedling trees. These
contests were continued for 3 years, then dropped. They were
resumed in 1911 by the Northern Nut Growers' Association, a society
founded in 1910 by W. C. Deming, then a physician of Now York
but now living at Litchfield, Conn. Dr. Morris was its charter pres-
ident. The association has held many nut contests, the last in 1934.
During recent years other similar contests have been held. In
1926, under the guidance of J. Russell Smith, professor of economic
geography, Columbia University, New York, N. Y., a contest for
hickory varieties was held by the Philadelphia Society for Agricul-
ture. A contest for northern nuts, including hickories and other
species, was held in Michigan in 1929, under the guidance of the
experiment station at East Lansing, and two excellent varieties of
shagbark were brought out, Mann and Miller. These appear to be
as promising as any yet discovered. The ownership of the parent
trees has since changed hands one or more times, but both varieties
have been successfully established by various persons, including G.
A. Zimmerman, Harrisburg, Pa.
A similar contest for hickories was held in Ohio in 1933, and one
for walnuts in the following year. New York held a general contest
for nuts in 1934. The Ohio contests were sponsored jointly by the
experiment station at Wooster and two members of the Northern
Nut Growers' Association, C. F. Walker, of Cleveland Heights, and
Homer L. Jacobs, of Kent, Ohio. The New York contest was di-
rected by the State Experiment Station at Geneva, Cornell University
at Ithaca, and S. H. Graham, Ithaca, a prominent member of the
Northern Nut Growers' Association.
Following the discovery of the Perkiomen shellbark, previously
mentioned, the shellbark seems to have received little attention until
about 1915, when J. F. Jones, Lancaster, Pa., selected, named, and
began propagating the Stanley shellbark from near Carthage, Ind.
Other shellbarks, probably more desirable, have come to light during
recent years. Along with the shagbark and the shellbark, a number
of other hickories, such as mockernut, Hicoria alba (L.) Britton, and
sweet pignut, H. ovalis (Wang.) Ashe, have been included in the
search for varieties of merit. The mockernut is a handsome tree with
dense, dark green, fragrant foliage, trunk bark without scales, and
nuts having thick hulls, very hard shells, and small but sweet kernels.
The sweet pignut also has handsome foliage and smooth bark. The
hulls are thin, the shells moderately so, and the kernels often nearly
as rich and sweet as shagbark. Neither species is as commonly
associated with rich bottom lands as are the shagbark and the
shellbark.
Few varieties of sweet pignut have been recognized or propagated.
Probably the first and one of the very few introduced was Brackett,
discovered in 1890 by G. B. Brackett, then of Denmark, Iowa. On
the basis of nut characteristics alone a number of varieties of mocker-
nut and other hickory species and types have been named, but very
few of these are especially promising and in a majority of cases con-
siderable uncertainty exists as to the identity of the reputed species.
Many natural hybrids between Hicoria species have been given
varietal names and propagated to some extent. In many cases the
NUTS 855
parentage on both sides is reasonably certain, but in others it is a
matter of conjecture. Some of the earliest hybrids to become known
were apparently pecan X shellbark crosses, including McCallister
from Indiana, Nussbaumer from Illinois, and Rockville from Missouri.
The Burton variety from near Owensboro, Ky., is supposed to be a
pecan X shagbark cross. All of these were first grafted during the
early nineties, or possibly earlier.
The natural type of hybrid of special value occxirring most fre-
quently among the hickories is probably shagbark X shellbark, one of
the best varieties of which is Weiker, discovered in Lancaster County,
Pa., by J. G. Rush, of West Willow, and first propagated in 1903 by
J. F. Jones, then of Monticello, Fla. Other supposed hybrids are
apparently crosses between pecan and bitternut, shagbark and
bitternut, and. pecan and mockernut.
Problems and Possibilities in Hickory Breeding
Hickory nuts have never met with the popular favor accorded pecans
and black walnuts. In the shell they bring too low prices to justify
shipment over long distances or extensive handling. Sale in the
shelled condition is largely limited to small lots in local markets.
Before nuts of the slow-growing hickory species can be expected
to become popular enough with consumers to justify the planting of
extensive orchards, irrespective of time or cost involved in bringing
the trees into full bearing, varieties must be found or developed that
can be shelled easily. Until this is done hickory nuts in the shell will
probably continue to compete poorly with pecans, almonds, chest-
nuts, peanuts, and many of the Persian walnuts, most of which can
be shelled easily without mechanical aid. All known varieties of pure
species, and with few exceptions all of the hybrids, have shells either
too thick or too hard to be cracked readily in the hands, though the
shells of many may be readily broken open with a light tap of a
hammer or by the use of some of the hand-power devices now on the
market. The shells of many varieties split open when the nuts are
hit on an edge with a hammer in such way as to release one half ker-
nel perfectly while the middle partition hofds the other half practically
as securely as before the nut was broken open. A few varieties of
shagbark have been found with shells of such thinness that breaking
in the hands is not difficult, but in all such nuts that have been
examined by the writers the cleavage has not been good. Instead of
cracking along definite lines, the shells have merely mashed at the
points where pressure was applied with another nut. With the ex-
ception of the pecan X hickory hybiids and pure pecans, which are
usually oblong, all nuts of hickory varieties have been generally
roundish in form and therefore quite unsuited for shelling in auto-
matically fed machines.
The parent trees of some of the varieties are known to be heavy
bearers during favorable years, and top-worked trees have come into
bearing relatively soon, that is, in about the same time as is required
for apples. The kernels of some are plump, bright-colored, sweet,
and palatable. To many persons, especially to those who knew good
shagbarks an'd shellbarks in childhood, no other nuts taste so good.
856 YEARBOOK, 1937
However, it is too early in the growing of these hickories to know how
well any of them will be received by consumers, even when prepared
in convenient and attractive form.
The problem of breeding other hickories, as in the case of the pecan,
is difficult because of uncertainty as to what characteristics are likely
to meet market requirements best. However, it may be assumed
safely that the requirements for these hickories will not be very unlike
those of the pecan and other nuts that are popular in the shell. In at
least one respect other hickories should have an important advantage
over the pecan. With the latter, seedling nuts of good size, good form
for shelling, thin shells, and general excellence are not uncommon in
the wild product. If such nuts exist among other hickories they
have not yet been brought to light, in spite of many searches that have
been made. When superior varieties of hickory are developed by
breeding, as seems well within the realm of probability, they will
have no competition with nuts of the same types, either wild or
imported.
A small amount of breeding of other hickories by hybridization has
been undertaken by the Bureau of Plant Industry. The objectives
are much the same as for pecans. However, hardiness is more im-
portant than with the pecan because there is greater demand for
varieties that can be grown successfully beyond the northern limits
to which the various species are naturally adapted. This demand is
from home owners who at present are unable to grow nuts of any
kind for family use.
Nature has already laid much of the foundation for the hybridi-
zation program with hickories. It has produced many interesting
hybrid forms, of which some may have considerable horticultural
value. The majority of the first-generation hybrids are of little or
no value except for novelty planting or further breeding. Very few
second-generation hybrid populations have been grown, and until
facilities are available for growing and studying large numbers of
such progenies, progress will be slow in the selection of new and valu-
able types.
The natural hybrids are suggestive of what may be expected from
crosses between certain species. For example, thinness of shell, and
to a varying degree astringenoy, seem to be dominant in all bitternut
(Hicoria cordifortnis (Wang.) Britton) hybrids, and elongation of nut
seems dominant in pecan X shellbark hybrids. Also, large size and
uncertain or poor filling appear to be characteristic of hybrids between
the pecan and either the shagbark or the shellbark.
By systematic breeding it should be possible to extend the range of
the shagbark and other good hickories both north and south of present
limits. A new form having the thinness of shell, the easy shelling
character, and the rich quality of the pecan, the whiteness of shell of
the shagbark, and the flavor of either pecan or shagbark, would be a
great benefit to the nut industry. Such a nut is needed by orchardists,
small home owners, and consumers.
In the appendix are given the names of breeders interested in im-
provement of the hickory and a list of varieties of probable value for
breeding.
NUTS 857
WALNUTS
Black Walnut
Five species of black walnut occur naturally in this country. Four of
these are from the far West and Soiithwest and one from Texas. Of
the former, two are from California, one from Arizona and New Mexico
and one from New Mexico, Texas, and Oklahoma. The two California
species are known as the Hinds or northern California walnut, Juglans
hindsii Jcpson, and the southern California walnut, J. calif ornica
S. Wats. The former grows to be a fairly large tree, now more com-
monly seen along roadsides and about residence grounds, where it has
been planted for shade and ornamental effect, than in forests and
fields. Nursery seedlings of this species are the stocks chiefly used on
which to graft varieties of the Persian walnut.
The southern California walnut is a smaller growing and less valu-
able tree. It varies greatly in habit, depending upon its environment.
Being drought-resistant, it often occurs in dry, gravelly, or unfriendly
soils where other species of walnut would certainly fail entirely. Under
such conditions it develops as a true shrub only 5 to 10 feet in height
instead of as a standard tree. When conditions are more favorable it
grows rapidly and becomes a fairly good-sized tree. It differs from
the Hinds walnut in lacking a central leader, as its branches spread
out in more or less vase shape. It is not planted to any great extent.
The two walnut species native in the Southwest are much alike and
nowhere of great value. One is Juglans major (Torr.) Heller, from
Arizona and southern New Mexico. This sometimes attains a height
of 50 feet and a trunk diameter of from 3 to 4 feet, although ordinarily
it is a small tree. The other species is J. rupestris Engelm., from parts
of New Mexico, Texas, and Oklahoma. This is a shrubby tree rarely
attaining a height of 30 feet. The nuts are the smallest of any Amer-
ican walnut. Generally speaking, all of these western and south-
western walnuts are of little value for either timber or nut production.
They should be useful, however, in breeding hybrid strains for that
part of the country.
The eastern black walnut, Juglans nigra L., is the most important
native walnut of this country in both timber and nut values as well
as in extent of native and adapted range. No other American timber
tree equals it in value for such special uses as cabinetmaking, interior
finishing, and the manufacture of many articles, particularly gun-
stocks. Few other tree species are so widely distributed over the
entire United States. It is grown to some extent in practically every
State in the Union. Under the most favorable conditions it some-
times attains a height of 100 to 150 feet and a trunk diameter of
more than 6 feet. The nuts are variable in size, form, thickness of
shell, and shelling quality and also in character and flavor of kernel.
The kernels of this species are favorites with manufacturers of con-
fections and baked goods on account of the extent to which the pleasing
flavor is retained in the cooking processes. So far as known, the
eastern species is the only black walnut thus far used in breeding.
The history of breeding the eastern black walnut closely parallels
that of the northern hickories. It has been limited chiefly to the
selection of varieties from wild trees, the propagation and testing of
138!)04° — 37 SB ++
858 YEARBOOK, 1937
many of these by amateurs, and the commercial planting of a few.
The Thomas variety from Montgomery County, Pa., discovered,
named, and first propagated about 1880 by J. W. Thomas & Sons,
nurserymen, of King of Prussia, Pa., appears to have been the first
to attain varietal status. It has since been widely disseminated and
is still the general favorite with most planters. Its seedlings are
notable because of their vigor and rapid rate of growth. Six varieties,
including Thomas, were described by the Department of Agriculture
in a special report (16) issued in 1896. One of these was named
Peanut because of the more or less cylindrical and peanutlike shape
of the single-lobed kernels. So far as is known, with the exception
of Thomas, no other of these varieties is now being grown.
The introduction and testing of black walnut varieties received
little further attention until early in the present century. It was
largely as a result of nut contests begun in 1905 by Morris, and later
expanded by the Northern Nut Growers' Association and other organi-
zations and individuals, that this interest became somewhat general.
The industry received its next major impetus about 1915 when the
prize varieties were first propagated by nurserymen and made avail-
able to the public. A large number of promising varieties are now
on record. Many of these have been propagated to some extent.
Following the lead of Morris in bringing out new varieties, and
cooperating closely with him, mainly through the Northern Nut
Growers' Association, W. C. Deming, J. Eussell Smith, Swarthmore,
Pa., the late W. G. Bixby, and the Tate J. F. Jones conducted many
surveys in the East to discover black walnut seedlings suitable for
varietal recognition. The Bureau of Plant Industry has participated
actively in all of these efforts.
During recent years other black walnut contests have been con-
ducted by the State experiment stations of Michigan, Ohio, and New
York, and also by a number of individuals, especially N. F. Drake,
Fayetteyille, Ark., and H. F. Stoke, Roanoke, Va. In most of the
association contests Deming did much of the detail work and par-
ticipated actively in all judging. In this he was closely followed by
Bixby during a period of about 15 years beginning in 1918. Smith
took entire charge of advertising the 1926 contest, which was one of
the most important ever held by the association. He has been one
of the principal judges in several of the contests.
Of the eastern black walnut varieties that have been brought to
light in various ways, several are now grown by nurserymen. The
best known of these are Creitz from Indiana, Cresco from Iowa,
Ohio from Ohio, Rohwer from Iowa, Sifford from Virginia, Stabler
from Maryland, Stambaugh from Illinois, Tasterite from New York,
Ten Eyck from New Jersey, and Thomas from Pennsylvania. Many
other varieties from New York to Arkansas and from Minnesota to
Virginia are also being tested, primarily by individuals, although to
some extent by public institutions. Many of these merit much
greater attention than they are receiving. Unless they are propa-
gated soon, they are likely to be lost.
The Bureau of Plant Industry has made many crosses for the pur-
pose of developing better varieties, but so far all have suffered from
adverse circumstances and few nuts have been produced. A small
NUTS 859
number of hybrid trees are now growing on the grounds of the United
States Horticultural Station at Beltsville, Md. The Minnesota Agri-
cultural Experiment Station is growing many seedlings of certain
northern varieties for the purpose of selecting individuals hardy and
otherwise of merit in that latitude.
As with the hickories, practically no varieties of black walnut have
yet been fully tested in orchard plantings. The shells of all black
walnut varieties yet recognized are much too thick to be cracked except
by mechanical means, although some shells are less thick than others.
Butternut
What has been said concerning the varietal status of the eastern
black walnut is largely applicable to the butternut, Juglans cinerea
L., although considerably less progress has been made in the develop-
ment of choice varieties. This species has a rather restricted range
within the Eastern States, but it occurs naturally as far west as eastern
Nebraska. At present it is nowhere abundant over large areas. As
a tree it does not equal the black walnut in size, although in a favor-
able environment it sometimes reaches 100 feet in height and nearly
4 feet in trunk diameter. The nuts are oblong, cylindrical, sharp-
pointed at the apex, bluntly rounded at the base, rough and jagged
over the surface, and. usually thick-shelled. Nevertheless some varie-
ties have very good shelling quality and the majority have kernels
with a rich, agreeable flavor. In cooking and in the manufacture of
confections the butternut shares the popular favor of the black walnut.
The first variety of butternut to be named seems to have been
Aiken, discovered in 1917 by S. E. Aiken, Grasmere, N. H. It was
first propagated in 1918 by J. F. Jones, Lancaster, Pa. Other varie-
ties have since been found mainly as a result of contests held by the
Northern Nut Growers' Association, but none have been com-
mercialized.
While most varieties of butternut have thick shells and are difficult
to crack, some crack so well with hand-power machines, of which
several are on the market, that the kernels are released in unbroken
halves.
This species has been greatly neglected by horticulturists. -Besides
producing nut kernels of excellent quality the species is the hardiest
member of the walnut genus, its native range extending well into
Canada. It is abundantly worth development wherever it succeeds,
especially in the North.
Japanese Walnut
The Japanese walnut, Juglans sieboldiana Maxim., was first intro-
duced into this country about 1860. It has since been widely tested
in practically all parts of the country without anywhere attaining
great importance. The tree has much the size and general form of a
large apple tree. Its nuts are of two distinct shapes, and botanists
at one time thought there were more than one species. One of these
was called J. cordiformis Maxim., literally "heart shaped", from the
shape of the nuts. However, there is but one species, as the tree
characteristics are identical, and seed nuts of either type produce
offspring of both fruit types as well as of many intermediate forms.
860 YEARBOOK, 1937
The nuts of both types are smaller, of smoother surface, and with
somewhat thinner shells than eastern black walnuts. In general,
both Japanese walnut typos are top-shaped and sometimes sharply
pointed at the apex. Those once called Juglans cordtformis are now
known as hcartnuts. These are the better of the two and are now
receiving the attention of horticulturists. The late J. F. Jones prop-
agated a number of varieties, beginning in 1918 with one that he
called Lancaster. Somewhat later he introduced Bates, Faust, and
Ritchie. These make quick-growing trees of much ornamental value.
The nuts are excellent. Often the flavor is indistinguishable from
that of the best butternuts.
The Japanese walnut, the butternut, and the Persian walnut
blossom about together and 2 or 3 weeks ahead of the black walnut.
Consequently they hybridize freely. The stamens and pistils of
individual flowers mature at different times, usually the stamens first,
and_ this, with wind distribution of pollen, tends to promote cross-
pollination. By breeding it should be possible soon to develop valu-
able new_ forms not grown elsewhere, which would therefore have no
competition with others of their own kind either imported or grown
in the forests of this country. The hybrids are usually very vigorous
and luxuriant in foliage, but fruit setting is sometimes very meager
in spite of abundant production of both staminate and pistillate
blooms. Size of tree seems to have little relation to the number of
nuts produced.
Seedling Japanese walnuts grown in this country often produce nuts
greatly resembling butternuts. This occurs with any generation,
beginning with direct importations and continuing indefinitely. With
imported seed this is undoubtedly due to reversion to a parent type
common in the Orient, known as the Manchurian walnut, Juglans
mandshurica Maxim., which is so much like the American butternut
that it is considered to be the same by most travelers from this
country. In other cases the resemblance is quite definitely known to
be due to hybridization with either butternut or Persian walnut. It
is possible that there may be occasional crosses with the eastern black
walnut, J. nigra, but no case in which this appears probable has come
to the attention of the writers.
As a rule the nuts of butternut type borne by possibly hybrid
Japanese walnut trees are usually of little value owing to the thick-
ness of the shells and poor quality of the kernels. However, two
varieties of apparently hybrid origin with the butternut as a parent
are being propagated to some extent. These are Helmick from Iowa
and Creitz from Indiana. The former is a discovery of James K.
Helmick, Columbus Junction, Iowa, and the latter was brought out
by W. A. Creitz, of Cambridge City, Ind., after whom a variety of
black walnut was also named.
Persian (English) Walnut
The Persian (English) walnut, Juglans regia L., is the best-known
and most widely grown nut-bearing species of the North Temperate
Zone. The tree is handsome, large, and of great value wherever it
succeeds, both on account of the nuts it produces and for its timber.
It is native to western and central Asia. Its nuts form an important
NUTS 861
article of food and of general commerce. Production is important in
California, Oregon, and to some extent in Washington in this country,
in many European countries, in China, and to some extent in Chile.
The origin and early history of this walnut is concisely given by
Heiges (16), who wrote:
It was known to the Greeks, who introduced it from Persia into Europe at an
early day as "Persicon" or "Persian" nut and "Basilicon" or "Royal" nut.
Carried from Greece to Rome, it became Juglans (name derived from Jovis and
glans, an acorn, literally "Jupiter's Acorn" or "Nut of the Gods"). From Rome
it was distributed throughout continental Europe.
It reached England prior to 1562. There seems to be no clear
record of the first introduction of this walnut into the United States,
but occasional references and other evidence indicate that it came with
the earliest settlers. Bobbins and Ramaley (31) state that "In
colonial days, the term English was used to distinguish this walnut
from the native American black walnut and because at that time the
nuts were imported via England."
At present Persian walnut trees occur quite frequently along the
Atlantic seaboard from Long Island Sound west to Rochester, N. Y.,
and south to Virginia. Old trees, mostly in decrepit condition, are
not uncommon. What is perhaps the oldest if not the largest Persian
walnut in the United States stands on what is known as the Jacob
Bauder farm, 7}{ miles northeast of Reading, Pa. This tree was dis-
covered in 1922 by the late J. F. Jones and was determined by him to
be 210 years old. It measured 15 feet 1 inch in circumference at 4 feet
from the base and had a limb spread of 90 feet. It is supposed to have
been planted by the earliest German settlers.
Under the heading "A Giant English Walnut", the American
Garden for September 1888 gave an account of a number of Persian
walnut trees, one of which was still standing at that time and had been
part of a planting by Roger Morris, an English gentleman, who in 1758
built a spacious mansion on his estate on Manhattan Island. The
supposition is that the trees may have come from the Prince Nursery,
Flushing, N. Y., which was established in 1713, 45 years previous to
the Moms planting.
Other definite evidence of early planting is afforded by the so-called
James River Hybrid, which was cut down in 1928. It stood on Rowe
Farm, opposite Brandon, near the bank of the James River in south-
eastern Virginia. This was believed to. have been a natural hybrid
between the Persian and the eastern black walnut. Its apparent age
was estimated by Bisset (9), who observed it in 1911, to have been
from 150 to 200 years. As the year of Bisset's visit was 304 years
after the settlement of the first successful English colony in this
country at Jamestown in 1607, it would seem probable that the Persian
walnut parent was brought from Europe and established there by
colonists some time during the first century of English colonization in
this country.
According to Lelong (21), the Persian walnut is supposed to have
been introduced into California by the Franciscan monks in 1769.
He reported that the earliest planting outside of the missions was
made in San Diego probably in 1843, and that a second such planting
was made near Calistoga in 1848.
862 YEARBOOK, 1937
The first Persian walnut planting in California to lead to com-
mercial development was made by Joseph Sexton, of Santa Barbara,
from nuts presumably of Chilean origin, bought by him in San Fran-
cisco in 1867 (86). Nuts from the Sexton trees were later used for
growing seedlings for extensive orchard plantings in southern Cali-
fornia. The nuts from these are known on the market as Santa Bar-
bara soft-shells. Hard-shell walnuts were planted in northern
California at about the same time as in southern California. It
remained, however, for Felix Gillet, a Frenchman, who established
the Barren Hill Nurseries at Nevada City, in 1871, to arouse interest
in the whole State in grafted walnut trees of soft-shell varieties. He
early imported many shipments of scions and nursery trees and was
the first to introduce into California practically all of the best French
walnut varieties now grown in this country.
Plantings of seedling Persian walnut trees are known to have been
established in Oregon during the seventies or early eighties, as occa-
sional seedling trees estimated to be from 50 to 75 years of age are to
be found in the Willamette Valley of that State. The first commercial
planting in Oregon consisted of seedling trees put out in 1893 by L. T.
Davis, of Dundee, Oreg.2 This orchard was later purchased by
Thomas Prince, by whom it was materially expanded and made famous
for many years as the Prince Orchard. Grafted trees began to appear
in the Pacific Northwest during the late nineties, when A. A. Quarn-
berg, of Vancouver, Wash., and others first planted trees of French
varieties, which they procured from Gillet.
The practice of breeding walnut varieties by selection appears to
have been inaugurated by the French. L. D. Batchelor stated in an
unpublished report on walnut culture in France that some of the
varieties, such as Mayette and Franquette, had been grafted for over
100 years, and that the present commercial walnut industry of
France is based upon grafted walnuts.
The planting of the seedling trees by Sexton was followed by
marked expansion of seedling orchards in the southern part of Cali-
fornia until about 1900, when many individual trees began to be
selected and used as new varieties. Since about 1905 practically all
plantings have been of named varieties and many seedling orchards
have been top-worked.
In the Eastern States for approximately 10 years, beginning about
1915, efforts were made by J. F. Jones, and others to develop Persian
walnut varieties that would be hardy in that section of the country.
It was assumed that hardiness would be increased by grafting varie-
ties on stocks of the eastern black walnut, Juglans nigra. However,
practically all of the varieties so developed have since become obso-
lete, as they proved too subject to injury by winter cold or late
spring freezes. Hardiness was apparently not affected appreciably
by the use of black walnut stocks.
Persian walnut breeding by cross-pollination is still in the initial
stages. Much preliminary work has been done in the way of conduct-
ing studies of blossoming habits and of pollen behavior. Varieties of
this species are largely dependent upon other varieties or species of
' Personal statement made July 21, 1910, in Washington, D. C, by E. E. Lake, former professor of horti-
culture and forestry, Oregon Agricultural College, Corvallis.
NUTS 863
walnut for pollen for the reason that their own pollen is often not
available at the time it is needed. This is because the staminate
or pollen-producing flowers do not function simultaneously with the
pistillate or nut-producing flowers. Usually in such cases the stami-
nate flowers mature and shed their pollen, dry up, and fall to the
ground before the pistillate flowers become receptive. Occasionally,
however, this order is reversed and the pollen is shed too late to func-
tion on earlier maturing stigmas. Young trees seldom produce
staminate flowers until several years after the appearance of the
first pistillate flowers. Wood (46) has found that varieties of this
species are entirely fertile to their own pollen when it is available
at the right time, and equally fertile to pollen of any other species of
Juglans.
Persian walnut hybrids, resulting from natural crosses with the
Hinds walnut (Juglans hindsii) of northern California, occur with
great frequency in that State. In the East natural hybridization is
not uncommon with the eastern black walnut (J. nigra) or with the
butternut (J. cinerea) and occasionally with the Japanese walnut
(J. sieboldiana) . No hybrid of these types yet found has been of
horticultural value, although often the trees are vigorous growers of
much beauty and not infrequently of greatly increased hardiness. No
doubt some of these hybrids would furnish timber of value; but the
cost of developing hybrids, added to that of bringing walnut trees
of any form to timber age, is entirely too great to justify considera-
tion of hybrids for this purpose under present economic conditions.
The few nuts produced by these hybrids are usually thick-shelled
and contain very little kernel.
Breeding the Persian Walnut
The principal weak points in present varieties of Persian walnuts
are susceptibility to bacterial blight, lack of hardiness sufficient for
conditions in the Eastern and Northern States, lack of uniformity in
bearing, and general lack of quality of nuts. Some varieties have con-
siderable astringency in the pellicle of the kernels, owing to the pres-
ence of tannic acid.
Practically all varieties are susceptible to walnut blight, a serious
bacterial disease affecting both nuts and twigs. This disease is now
being controlled by proper spraying, but only at great expense. Lack
of hardiness is a definitely limiting factor in the East, although there
are occasional trees in many of the Eastern States. Trees that survive
longest in this region usually have the protection of buildings, lakes, or
other agencies that modify local temperature extremes. The Persian
walnut is quickly responsive to warm periods in late winter or early
spring and consequently is vulnerable to frost injury. When injured
by frost or other mechanical agency the tree recovers slowly. Loss by
freezing is a matter of universal concern in commercial walnut dis-
tricts of Europe, Asia, and the United States.
Variation in annual yield largely results from environmental influ-
ences and would be difficult to overcome or reduce through breeding
alone. Nevertheless, it is more serious in some varieties than in others,
and development of greater fruitfulness should result in appreciable
improvement.
864 YEARBOOK, 1937
Some varieties are more resistant to blight than others, and because
of slow response to mild temperatures, some are less subject to injury
by cold in winter or spring. Other superior qualities of some varieties
include f ruitf ulness ; uniformity in size of yearly crops; shells well-
sealed at the ends and so firm that they do not crack while being
handled, although they are easily cracked by machine or hand; very
little or no astringency in the pellicle ; and richness and palatability of
kernel. Such varieties, each having certain good qualities, are the
material from which the breeder hopes to develop new varieties having
combinations of larger numbers of desirable characteristics.
The problems involved in breeding by cross-pollination are not
unusually intricate. While it is possible that better varieties or better
basic material for use in breeding, particularly in the matter of hardi-
ness, might be obtained from some foreign country, this does not seem
probable, as the principal walnut regions of the world have been fairly
well searched. It is believed that an abundance of varieties and strains
of types desirable for breeding is already within this country. As a
rule French varieties are the hardiest among grafted kinds, although
a few seedlings in the East, probably of German origin, may be some-
what more hardy. However, eastern-grown Persian walnuts seldom
have the high quality and relative freedom from astringency of pellicle
characteristic of the western nuts, such as the French and the Santa
Barbara soft-shell varieties.
Persian walnut breeding has thus far been confined to selective
methods for developing greater hardiness, greater resistance to blight,
heavier bearing habits, and nuts of superior quality. Nuts are desired
of large but not too large size, of good sealing quality, and with shells
thin enough to crack readily without breaking during normal handling.
The kernels must be plump, bright, smooth, free from prominent
points that break off easily, rich in quality, sweet in flavor, and without
tannic bitterness in any part of the pellicle.
The New York (State) Agricultural Experiment Station has made
crosses between Juglans regia and J. nigra in the hope of developing
walnuts of the Persian type hardy at that latitude. Similar crosses
have been made by the Minnesota Station at University Farm, St.
Paul. In both cases the first-generation offspring has shown increased
hardiness as well as vigor, but the nuts have been of little value.
In Mexico a certain amount of breeding by selection and of variety
testing is being conducted under the direction of G. Gandara, Secre-
tariat of Agriculture, Department of Stations and Experimental
Fields, Mexico, D. F.
Breeding by selection to develop superior or even more hardy
varieties of Persian walnut appears to have about reached its practical
limit, as the principal walnut-growing regions of the world have been
more or less thoroughly surveyed and no new varieties of outstanding
merit have been found in considerably more than a decade. How-
ever, an effort is now being made by P. C. Crath, of Toronto, Canada,
with the financial aid of Carl Weschcke, St. Paul, Minn., to procure
Juglans regia seed from certain known trees in the Carpathian Moun-
tains of Poland, which, it is hoped, will produce seedlings hardy in
northern parts of this country and Canada. Distributions of seed
nuts from that source have already been made more or less generally
NUTS 865
throughout Wisconsin, Minnesota, the Dakotas, and Ontario, Canada.
Reports as to the behavior of resulting seedlings are contradictory,
but there is a possibility that some of the Crath introductions ■will
prove suitable for limited use in home plantings where other trees of
the same species have not been hardy.
Breeding by hybridization in the hope of developing an entirely
new form of walnut, which would be distinctly unlike any existing
form and therefore would have no direct competition, is now being
planned by the Bureau of Plant Industry for the early future. This is
to be undertaken by crossing the Persian walnut with the butternut
for hardiness and flavor, and probably with the eastern black walnut
for a blend of excellent flavors and possible greater timber value.
Crosses will be made so as to include the best of the Japanese walnuts,
as that group is more hardy than the Persian walnut and will grow
farther south than the butternut. Heartnut trees do not attain the
great size of the eastern black walnut, and from that standpoint they
are more desirable for orchard purposes.
Hybridization of varieties strictly within the species with possible
infusion of characters from some other species on the western coast
should greatly improve resistance to disease, hardiness, fruitfulness,
and the general quality of nut. However, plans for breeding of this
sort do not appear to have been announced by any institution or
individual. Nevertheless, the possibilities are so great and the field so
inviting that it is hardly to be conceived that it will long remain
neglected.
In the appendix are listed varieties of black walnut, butternut,
Persian walnut, and Japanese walnut, likely to be of value in breeding
work, and the names of plant breeders who are actively working with
Juglans. ALMOND
The almond, Amygdalus communis L., is a close relative of the peach
and therefore a member of the botanical family Rosaceae. It resem-
bles the peach in appearance of tree, foliage, and flower. It is one of
the earliest orchard fruits to blossom. In this country the blooming
period is from January to March, and on this account it succeeds only
m regions where there is minimum danger of killing temperatures
during that period. It requires a definite although short period of
complete dormancy, without which it tends to become evergreen.
For this reason it is unsuccessful in the mild regions of the South.
Two types of almonds are under cultivation, sweet and bitter. To
the former belong the familiar almonds of commerce, common in the
markets. Of these there are three types, depending upon the thick-
ness of the shells — hard-shell, soft-shell, and paper-shell. The Jordan
is a typical hard-shell variety, the Peerless a typical soft-shell, and
the Nonpareil a typical paper-shell. Seedlings of both sweet and
bitter almond are used as stocks upon which to bud edible varieties.
Like the Persian walnut, the almond is of Old World origin and has
been known and prized for food since the earliest times. It is sup-
posed to have originated in the Mediterranean Basin.
It is not improbable that improvement of the almond by crude
selection began quite as early as with any orchard fruit. There
is evidence that grafting was practiced long before the Christian
866
YEARBOOK, 1937
Era. The almond is easy to bud, and it is presumable that in very-
early times good almonds were worked on those less good and thus
perpetuated.
Almond varieties have been recognized as such for a century or
more in Spain, but varieties there are types rather than clons. Almonds
were first introduced into the eastern United States by pioneer hor-
ticulturists, but without success.
Later they were taken to Cali-
fornia, where, during the last half
century, their cultivation has be-
come an important orchard indus-
try. Introductions of varieties of
European origin into California
began before 1853.
The first varieties introduced
into California proved of little
permanent value and have since
been gradually supplanted by
others of California origin. Out
of 76 varieties rated by Wood
(45) as being of commercial im-
portance in California in 1925,
60 were of California origin, 4 of
uncertain origin (probably Cali-
fornia), and 12 only were from
Europe. None of the European
varieties was rated as being then
in favor with experienced growers
or apparently of value for future
use. However, the early intro-
ductions and their ill-advised
planting in various parts of the
State threw much light on the
possibilities of almond growing in
California and on environmental
and cultural requirements, and
furnished material for developing
better varieties.
Figure 7.— A. T. Hatch (1837-1910), Sui-
sun City, Calif., greatest contributor to the
development of almond varieties in this
country. During the eighties he originated
the so-called "Hatch varieties" IXL, Ne
Plus Ultra, and Nonpareil, which have since
been the leading sorts grown in California.
At that time these became his final favorites
out of many of the first selections made
by him from seedlings of a bitter almond
tree standing near a sweet almond by which
it had doubtless been pollinated.
Almond breeding by selection
from seedlings grown on a large
scale for the purpose appears to have long preceded similar work with
any other nut grown in this country. In 1878 A. T. Hatch (fig. 7), of
California, who at one time had almond plantings in 20 counties put out
at Suisun City an orchard of over 2,000 seedlings grown from nuts of a
supposedly seedling bitter-almond tree which stood near a tree produc-
ing sweet almonds from which its flowers were undoubtedly cross-polli-
nated.3 The purpose was to use these seedlings as stocks upon which
to bud good varieties. Concerning his next move, Hatch wrote:
I found a supposedly seedling almond which had been prolific in its bearing for
several years. It was small but soft-shelled, sweet, but hard to hull and therefore
» Letter from Mr Hatch in Department file written June 20. 1892; Nut Culture in the United States
US, p. 10); and recent statement by Mrs. P. C. Campbell, Vacaville, Calif., a daughter of Mr. Hatch.
NUTS 867
expensive to handle, though I thought it was better than one that did not bear good
crops, so I budded the seedling trees in place in the orchard with buds from these
trees (probably this tree) , but not having buds sufficient for all there were, some-
where near 300 remained seedlings. The second year after planting I found upon
some of these a few almonds, some of which seemed to be very fine, sweet, soft-
shelled almonds, when I concluded to leave them as seedlings until they might
bear fruit.
From then on he marked the trunk of each tree in such manner as
to indicate the character of the nuts and size of the crop. It was from
trees so marked that he made many selections, including two that he
later named IXL and La Prima.
Hatch was so pleased with the general character of the nuts from
these unbudded trees that he tried to induce those that he had previ-
ously budded to push out sprouts from below the buds in order that
they too might bear. In this way he was able to add greatly to the
total number of promising new sorts. Among those so discovered
were two that he later named Ne Plus Ultra and Nonpareil. These
two, together with IXL, were his final selections; and under the popu-
lar group name of "Hatch varieties" they later took rank among the
most important varieties of almond grown in this country. To some
extent these have been introduced into foreign countries.
The great majority of varieties now grown in California originated
as chance seedlings discovered by careful observers in various parts of
the State. A few were introduced from France, mostly by Gillet.
Several came from Spain as the result of introductions by David Fair-
child and Walter T. Swingle, of the United States Department of
Agriculture. However, next to Hatch it is probable that the man who
did most toward contributing valuable varieties to California was
A. M. Newlands, of Colusa. Newlands planted a sack of almonds in
1883, and 3 years later chose 4 seedlings, to which he gave the
names of California White, Commercial, Eureka, and Lassen (45).
Of these^ Eureka is one of the best small varieties in the State.
Breeding by hybridization was begun by M. N. Wood, of the United
States Bureau of Plant Industry, in 1923, in cooperation with the Uni-
versity of California. Thousands of crosses have been made and the
resulting seedlings brought to fruiting at the State Agricultural
Experiment Station at Davis, Calif. A number of promising seedlings
are now under observation. Two of these are being tested in many
parts of the State. Nuts from one of these and from both parents are
shown in figure 8.
Present Work in Almond Breeding
Few of the varieties producing the best nuts are good bearers . Some
of the best bearers are unsymmetrical trees, difficult to prune. The
nuts of many of those that bear well have hard shells or are of inferior
flavor. The shells of some others are of such softness that they crum-
ble badly in ordinary handling. A considerable portion of the kernels
of certain varieties are gummy and objectionable. In many cases the
foliage is seriously subject to red spider injury. Some varieties are
difficult to "knock" from the trees ; that is, to jar off when fully mature.
In some varieties there are often a great many "sticktights" or nuts
from which the husk separates poorly or not at all. A few of the varie-
ties most extensively grown produce nuts too small to bring good
868 YEARBOOK, 1937
prices. A not uncommon defect is that of forming double kernels,
called "philopenas."
If a variety of almond could be found combining all of the good
points of present varieties and seedlings, little more could be desired
in the way of a first-class almond. Such desirable characteristics as
late blooming; full bearing; good qualities for harvesting, hulling, and
Figure 8. — Two of the almonds used in breeding and their offspring, which is believed
to be promising as a new variety: A, Pistillate parent; B, staminate parent; C, the
offspring. X %. The nut of the new variety is superior to that of either parent in
being larger, brighter in color, and of thinner shell. The kernel is larger, brighter,
smoother, and of finer flavor. The tree is more fruitful and so far has been highly
resistant to the red spider.
shelling; a high degree of resistance to certain insects, particularly the
red spider, and to a number of diseases ; and general excellence of kernel,
are all to be found distributed among present varieties and seedlings.
The problem of the almond breeder is to combine as many as possible
of these good qualities in a few varieties. This should not be difficult,
as the technique of almond breeding, like that of other rosaceous
fruits such as apple, peach, plum, and others, is not especially difficult
to perform. Almond pollen is carried only by insects and not by
wind, and pollination is therefore easily controlled. This is quite
different from walnuts, hickories, chestnuts, and filberts, the pollen of
which is wind-carried, produced in great abundance, and difficult
to control.
NUTS 869
Present work in almond breeding by the Bureau of Plant Industry
is well-organized and, as already noted, is being systematically
carried on in cooperation with the University of California. Nuts
from crosses made by Bureau workers are planted in nursery rows at
University Farm, Davis. When the seedlings are 1 year old, scions
from some of the more vigorous growers are top-worked in old trees
and quickly brought into bearing. Large mimbers are soon eliminated
and only the most .promising are preserved. In 5 to 10 years after
the seed is planted further selections are made, and these are tested in
various almond sections of the State by top-working on established
trees. The work is making very satisfactory progress, although no
varieties are yet ready for general distribution.
With the possible exception of certain of the Jordan types as grown
in Spain — long, hard-shelled varieties, very popular with confec-
tioners, chiefly because of the form of the kernel — it is generally con-
ceded that the best almonds on the world's markets now come from
California. When the good points of the California varieties are
rightly combined there is abundant reason to expect that American
almonds will completely dominate the markets of this country.
Breeders now engaged in work with almonds are named in the appen-
dix, which also contains a list of almond varieties considered valuable as
breeding material. PISTACHE
The pistache, Pistacia vera L., is a small-growing, wide-spreading
tree up to 30 feet in height, dioecious in habit of flowering, and pro-
ducing nuts of much value. The nuts are small in size and borne in
clusters that often weigh several pounds. Each nut has a thin, reddish,
leathery husk. The shell of the nut is very smooth, whitish, and thin,
yet of bony hardness. It tends to split open slightly upon maturity,
but not to such extent as to release the kernel. The flavor is mild, the
texture fine, and the color of the kernel greenish throughout. When
finely ground, pistache kernels are used to give color and flavor to confec-
tions. The darker they are the better they suit the purpose. The nuts
are prepared for market by salting and roasting while still in the shell.
The pistache grows in hot dry regions where it withstands ad-
versity better than either the almond or the Persian walnut. It is
native in Syria and nearby regions. It was first introduced into the
United States in 1853-54 by the Commissioner of Patents, by whom
seeds were widely distributed throughout the Southwest. Little
interest was aroused, however, until 1876, when other introductions
were made by G. P. Bixford, of San Francisco, Calif., by whom trees
were brought into fruit in 1881. Many more recent introductions
have been made by the Division of Plant Exploration and Introduction,
Bureau of Plant Industry.
There are now numerous small plantings of pistache trees in the
interior valleys of central and southern California. For many years
the most extensive grower in that State was Claude Tribble, of Elk
Grove. He made many experiments in propagation, including the
use of different species as stocks upon which to graft the better varie-
ties. In his experience Pistacia atlantica Desf. proved more satis-
factory than P. chinensis Bunge. Others have used P. terebinlhus L.
as a stock with satisfactory results.
870 YEARBOOK, 1937
Much work is still necessary to determine the most satisfactory
pollinizers to use for the cultivated varieties. Practically no work in
breeding has yet been reported and so far as known none is planned for
the immediate future. However, the superior merit of this species
and its ability to grow under conditions to which no other nut of this
country is well adapted would seem to justify immediate attention by
our breeders. THE TUNG TREE
The tung tree, Aleuritesfordii Hemsl., is the hardiest and most valuable
member of a group of closely related tropical and subtropical trees
producing inedible seeds or nuts from which a valuable drying oil is
extracted. This oil has been used in the Orient for many centuries in
waterproofing wood, paper, fabrics, and other products. Within the
last half century it has come into important use in Europe and the
United States in the manufacture of waterproof varnishes, paints,
paint dryers, and linoleum. Tung oil is much like linseed oil but dries
more rapidly and is more resistant to water. The tree is handsome,
having a round top and dense, catalpalike leaves.
The species was introduced. in to the United States in 1905 by the
Division of Plant Exploration and Introduction through the efforts
of David Fairchild, then in charge, and United States Consul General
L. S. Wilcox, Hankow, China. It has since attracted wide attention
among planters in northern Florida, southern Georgia, and Gulf
Coast States westward to Texas.
The earliest plantings were entirely of seedlings chosen without re-
gard to hardiness, fruitfulness, or merit of nuts produced. In 1923
studies as to relative merits of strains and seedlings were begun by the
Florida Agricultural Experiment Station at Gainesville. Later, sim-
ilar work was taken up by the State stations of Georgia and Louisiana
and by certain individuals, notably the late J. B. Wight, Cairo, Ga.
Several selections have been made, and in a few cases these have been
placed on a varietal basis by budding and grafting in the nursery.
One commercial orchard of grafted trees consisting of about 4 acres
has been established at Cairo, Ga.
The Florida station found that seed nuts planted in early winter or
midwinter often result in trees ranging from a few inches up to 6 to 8
feet in height by the end of the first season. Such large trees may be
budded during the late summer or fall. The buds will remain dormant
until the following spring, when the tops should be cut back and the
buds made to push out. In this way budded trees suitable for trans-
planting may be grown in about 24 months from the time the seed is
planted.
Active hybridization was begun by the Florida station at Gaines-
ville in 1929. Several selections from the resulting seedlings have
since been made, but their value has not yet been fully determined.
Selective breeding at the Georgia Coastal Plain Experiment Station,
Tifton, Ga., begun in 1933, has resulted in the selection of three
promising seedlings, nos. 24, 39, and 49. Breeding through pure-line
selection and hybridization was begun at the Louisiana Agricultural
Experiment Station, Baton Rouge, in 1935. The objectives at each
of the stations are much the same; that is, to produce varieties that are
hardy, vigorous, and heavy producers of good nuts rich in oil.
NUTS
Figure 9. — Nature of growth and blossoming habits of hickories and walnuts as illus-
trated by the pecan. A, Twig showing staminale flowers (a) borne axillary on growth
of the past season and (b) pistillate flowers borne terminally on growth of the current
season. B, Section of a catkin showing three staminale flowers of the many that form
on each catkin. C, Enlarged staminate flower containing several anthers (a); b,
sepals. D, Single pistillate flower with rough stigma at a.
FUNDAMENTALS IN NUT BREEDING4
Complete pollen control is vital to efficiency in nut hybridization work.
The chief genera grown in this country are walnut, hickory (including
the pecan), filbert, pistache, chestnut, almond, and tung. With the
4 The following pages are intended primarily to give instruction to students and those professionally inter-
ested in nut breeding.
87-;
YEARBOOK, 193:
exception of almond and pistache, all are monoecious; that is, the
pollen and nut-producing (lowers form separately in different parts of
the same tree, as shown for the pecan in figure 9. The almond bears
perfect flowers; that is, stamens and pistils occur in the same flowers,
as shown in figure 10. The pistache is dioecious and bears the pistil-
late and staminate flowers on different trees. In general appearance the
tung flowers greatly resemble those of the almond, but they are imper-
fect, as stamens appear in some flowers and pistils in others. The pollen
of almond and tung
trees is carried by in-
sects; that of the wal-
nuts, hickories, filberts,
pistaches, and chest-
nuts is carried by wind.
In most wind-polli-
nated nut-bearing
species, dichogamy
exists to a greater or
less extent. This de-
velopment and ma-
turity of the staminate
(male) and the pistil-
late (female) flowers
at different times ne-
cessitates cross-polli-
nation. The degree
of dichogamy varies
with the variety, the
age and nutrition of
the tree, and seasonal
conditions. In the case of some varieties of the same or different
species, dichogamy is so complete that the trees are unfruitful unless
they are pollinated by another variety producing pollen at the time
the pistils are receptive. Some varieties are protandrous, that is,
mature their pollen in advance of the period of stigma receptivity of
the pistillate blossoms; while others are protogynous, that is, the
stigmas of the pistillate flowers are receptive before pollen is matured.
In other varieties there is a short and inadequate overlapping period
of pollen shedding and stigma receptivity. Therefore, the degree of
dichogamy in the material worked is of considerable importance in
nut-breeding operations and technique. In the case of the protan-
drous varieties pollen must be so collected and stored that it will
retain its viability until it can be used for selling or for pollinating
other varieties with later pistillate blossoms. The protogynous varie-
ties present a different problem in that the development of the
staminate (lowers must be forced by cutting off catkin-bearing shoots
and storing them in water in a warm place, or by obtaining pollen
from localities where the varieties blossom earlier in the season.
Procuring pollen is quite easy, since all that is necessary is to collect
the mature catkins just prior to the liberation of their pollen and to
place them on smooth, hard paper in a warm, dry room, where the
locules will soon open and release the pollen.
Figure 10. — Essential parts of an almond blossom: a,
Stigma; 6, style; c, ovary; d, anther; e, filament.
NUTS
873
The stage of maturity of pollen can be determined by the stiffness of
the catkins and the color of the anthers. Woodroof and his coworkers
(49) found that a pecan catkin that will not shed pollen within 48 hours
is relatively stiff, while one that will do so in 12 hours is limber. The
color of the anthers until within about 48 hours of the time when they
will begin shedding pollen is about the same as that of the leaves and
bracts. After that the green color is gradually replaced by the
orange yellow of the pollen. This description of pecan catkins applies
in general to those of other species of
Ilicoria as well as to Juglans, Corylus,
and Castanea.
In order to get a controlled cross it
is necessary to use unmixed pollen. This
is probably best procured by collecting
mature catkins shortly before any pollen
has been shed, washing them repeatedly
with running water, removing the excess
water with a sterile towel, and then dry-
ing the catkins slowly in a desiccator
or other similar container. The cations
should not be too green, as they will
be likely to wilt without shedding, or
the viability of the pollen may become
impaired.
With some species pollen loses its vital-
ity quickly. In making crosses it is not
infrequently necessary to preserve pollen
for some time while waiting for the
pistillate flowers of desired varieties to
mature. To do this successfully, pollen
that is thoroughly dry, yet fresh, must r. .. ,
, , i • • i x i_ l j -ii rieurell. — hiMiuinrnl consisting
be placed m yials or tubes plugged with of * nvpodermjc „eedle attached to
COtton and held at a IOW but not freezing a rubber bulb by means of a curved
temperature. glass tube, used by pecan breeders
Numerous methods have been used for in applying pollen to the stigmas of
controlling pollination in the wind-polli- pistillate flowers enclosed within
nated nut plants. Absolute control in cellophane covers,
such cases is quite difficult and requires
a special technique not needed with insect-pollinated plants. It is
essential that the pistillate blossoms be covered well in advance of
their receptivity with a material that will preclude pollination.
These covers must not be removed, even momentarily, while there
is pollen in the air. In the pecan it has been shown that pollen
is not shed when the relative humidity is about 85 percent; how-
ever, that does not insure that the air is free of pollen, for the
reason that it may not have had time to settle out. Woodroof
(47) found that the usual methods of covering the pistillate flow-
ers with cloth bags or paper sacks do not eliminate all possibility
of the entrance of pollen. Their findings were later supported by
investigations of Traub and Romberg (40). These latter workers
devised a method of using closely woven cloth bags impregnated with
paraffin to cover the pistillate blossoms. A hypodermic needle
138004°
-37-
-uG
874
YEARBOOK, 1937
attached to a rubber bulb (fig. 11) was used to introduce the desired
pollen by simply pushing the needle through the cloth bag and lightly
squeezing the bulb to force out the pollen. They also found that if
the covers were removed and the blossoms pollinated between 5 and
7 a. m., when the rel-
ative humidity was
about 85 percent, there
was little danger of con-
tamination. Later
Smith and Romberg
(34) improved the
method by using trans-
parent cellophane bags
made from sausage
casings. Since this
method of pollination
control is readily adapt-
able to all walnut and
hickory species, it will
be described in some
detail. Cellophane
sausage casings are
made in many different
sizes; usually a casing
1% inches in diameter
is satisfactory. These
casings are seamless
tubes, usually sold in
lengths of approxi-
mately 32 feet. They
are cut to the length
desired, and one end is
closed by tying, folding
over and tvinST ajrahl Figure *& — Cellophane cover cut from a sausage casing,
The' finished case or u8.ed in PJev.entnns »™*Mf Pol'«" '«>"> caching the
+ K Vi ' 1 1 K A + K st,gmas °' pistillate pecan flowers to be used in breed-
tUDe snOUHl De 4 tO S jng This js p]ugged witn cotton at tbe lower end and
inches long. Ine tied tightly at the upper end. The pollen is applied by
tubes are placed Over means of a hypodermic needle (fig. 11) driven through
the clusters of pistillate the cotton.
flowers well before the
stigmas become receptive. A plug of cotton batting is wrapped
around the blossoming shoot so that the lower end of the tube can
be tied over it (fig. 12). The cotton plug provides ventilation for
the pistillate flowers. When the stigmas become receptive they are
pollinated with the desired pollen by pushing the hypodermic needle
through the plugs and blowing pollen over the stigmas by pressure
on the rubber bulb in which the pollen has been placed. Separate
needles and bulbs must be used for each variety of pollen, or if the
same outfit is used it must be sterilized with 95-percent ethyl alcohol and
carefully dried when changing from one variety of pollen to another.
Pollination control in the almond is quite simple. The flowers are
emasculated by the removal of the stamens and petals before any
NUTS 875
pollen is shed. In practice the emasculated flowers are usually cov-
ered with manila bags, or the trees are enclosed in tents or cages
made of muslin or wire screen of fine mesh, to prevent the introduc-
tion of foreign pollen by insects. However, these safeguards are
probably unnecessary, since in rosaceous fruits, including the almond,
there is practically no wind pollination and insects do not visit emas-
culated flowers. When the stigmas of the almond are receptive they
are pollinated by being dusted with the desired pollen applied with a
camel's-hair brush.
Stigma Receptivity, Pollen Shedding, and Pollen Viability
There are no available data for some of the species of nut-pro-
ducing plants on the period of stigma receptivity, the time of pol-
len shedding and pollen viability, and the factors affecting them.
In some cases investigations on these points are under way but
incomplete.
The almond has a relatively long blossoming period, especially if
the time is counted from the opening of the first blossoms of the earli-
est varieties to the last shedding of pollen by the latest varieties.
Tufts and Philp (41) report that in practically all instances the first
pollen produced was found inferior in quantity and in viability to
that produced later by blossoms on the same trees. The abundance
and viability of pollen was found to vary with the variety and from
season to season, but generally pollen was abundant and viable. The
viability of pollen was found to be greatly affected by wind, cold,
and rain.
The filbert normally has a long blossoming period, often extending,
within the same variety, for more than a month, although when
temperatures are unseasonally high it may be short. According to
Schuster {82), either the filbert stigmas are receptive long before
they attain full size or pollen that lodges on their surfaces remains
there in viable condition until the stigmas become receptive. The
quantity of filbert pollen produced varies greatly according to
variety, temperature, and vigor and general condition of tree, and
no doubt it is influenced by other factors. The catkins^ begin to
form in summer, and there is great danger of their being injured or
killed during the following winter. ' For these reasons filbert pollen
often shows great differences in viability. Schuster found that pol-
len stored in an open vessel lost less than 25 percent in viability
in 2 weeks.
Normally the pecan, as well as other species of Ilicoria, produces
enormous quantities of pollen. Young trees generally produce catkins
for one or more years before any pistillate blossoms are formed.
Woodroof {49) reports that a single pecan catkin will normally shed
pollen for 2 days, a single tree for 5 to 6 days, and a single variety for
10 or 12 days. Conditions that are optimum for pollen shedding tend
to be destructive to its viability.
In order to gain some idea of the quantity of pollen produced by a
single pecan tree, Woodroof (48) made detailed observations and
counts on a 13-year old Mantura tree that had a total of 941
shoots on which there were 44,885 catkins. These catkins had
876 YEARBOOK, 1937
approximately 14,241,334 anthers that contained an average of 2,064
pollen grains each. The estimated number of pollen grains produced
by the tree, therefore, was 29,394,113,376. He points out that had
it been possible for each pollen grain to produce a nut, this tree
would have supplied sufficient pollen for slightly more than 229,000
tons of nuts.
The viability of pecan pollen varies greatly with varieties, seasonal
conditions, and other factors. Some years a high percentage of the
pollen is defective, while in others it is mostly viable. Woodroof (49)
stored pollen of 20 varieties under 10 different conditions of tempera-
ture and humidity and reported that "no temperature and humidity
condition was found under which pollen could be stored for longer
than 96 hours with certainty of germination." Smith and Romberg (84)
report that Success pollen from a healthy, vigorous tree, stored at
laboratory temperatures for 12 days, still gave a set of nuts, but
that under similar conditions Schley pollen remained viable for only
8 days.
Under the humid conditions of Georgia the normal period of stigma
receptivity of pecans was shown by Woodroof (49) to be about 5
days, but he pointed out that in rainy or cloudy weather the stigmas
might remain receptive for 10 to 15 days. Smith and Romberg (34,
35) found that under the relatively dry conditions of Texas this period
ranged from 12 to 28 days. All unpollinized nuts were found to drop
in 5K to 6% weeks after the last receptive date.
Walnuts also produce enormous quantities of pollen. Wood (46)
working with the Persian walnut found that in dry California a single
catkin produced from 1 to 4 million pollen grains, and that a single
tree would produce from \)i to 40 billion pollen grains in a single
season. A single stigma has a surface area of 10 to 50 square milli-
meters, yet he found the average number of pollen grains distributed
per square millimeter per 24 hours, when pollen shedding was at its
height, to be as follows:
Nn mber
Directly under the trees 8. 0
60 feet from nearest tree 4. 0
150 feet from nearest tree 2. 9
500 feet from nearest tree ]. 0
1,000 feet from nearest tree . 3
Yi mile from nearest tree None
Woodroof (49) on the other hand, found that in humid Georgia,
pecan pollen was carried in appreciable quantities for a distance of
3,000 feet, which would indicate that pecan pollen is lighter than
walnut pollen and may be carried considerably farther.
Individual walnut catkins were found by Wood to shed pollen during
4 to 6 days, but under conditions of hot, sunny weather, such as
normally prevails in the interior valleys of California at the time
walnuts are in bloom, shedding is often limited to 1 day. There is a
rather wide range in the development of the different catkins on the
same tree, and therefore the pollen-shedding period is much longer
than the time indicated for a single catkin. Wood (46) found great
variation in the viability of walnut pollen. Some pollen grains were
devoid of protoplasmic content, and others that appeared normal failed
NUTS 877
to germinate. The percentages of germinating pollen grains for differ-
ent varieties varied from 0 to 80 percent, the average being 23 percent.
Under field conditions the Persian walnut pollen loses its viability
within a few days after being shed from the anther. Artificially it
may be preserved best when kept in glass vials stoppered with cotton
and containing a small piece of the catkin to supply moisture to the
air in the vial. When kept in this manner and stored in a cool, dry
place, in many instances it remained fit for artificial pollination for
3 or 4 weeks. In other cases viability was completely lost within
2 weeks.
Walnut stigmas usually remain receptive for several days, depend-
ing largely upon weather conditions. Wood (46) obtained the best
results from the application of pollen when fluid was being secreted
by the glandular portions of the stigma tic surface.
Fertilization of Ovule and Development of Embryo
Among nut-producing plants, with the exception of the filbert,
pecan, pignut, and Persian and Manchurian walnuts, very little is
known regarding pollen-tube growth, ovule fertilization, or embryo
development. Even in the case of the species studied there is not
complete accord in the conclusions reached by different workers, and
such information as is available is far from complete.
According to Benson (7), the filbert pollen grain germinates by
developing a short tube, which enters the basal region of the stigma.
Here the sperm nuclei enter a resting stage, remaining in this condition
for 4 to 5 months. During this time the megaspore completes its
development, after which the pollen tube resumes its growth and the
fertilization of the egg occurs.
According to both Billings (8) and N. C. Woodroof (50), numerous
pecan pollen grams germinate on the surface and send tubes into the
stigmatic tissue. The tubes do not enter the stylar canal but grow
downward in the tissue on each side of the micropyle and enter the
ovary cavity at a point nearly opposite the chalaza. The pollen
tubes enter the cavity from 6 to 12 hours after pollination, but they
do not enter the embryo sac until about 2 weeks later. The actual
fusion of the egg and male nuclei probably occurs about 2 to 3 weeks
later, or from 8 to 9 weeks (2, 50) after pollination. The first division
of the fertilized egg occurs about 2 or 3 weeks later, or about 2 months
after pollination.
Shuhart (S3) reported that pecan pollination generally takes place
at the time of the differentiation of the eight nuclei of the embryo sac,
and that fertilization takes place about 2 weeks later. However, the
stage of embryo-sac development at the time of pollination varies
greatly with seasonal conditions and to some extent with the variety.
Langdon(M) reports that iri the pignut, Hicoria glabra (Mill.) Britton,
the megasporocyte has reached the megaspore stage or one of the
early stages in gametopbyte development at the time of pollination.
The interval between pollination and fertilization is from 16 to 18
days, while the first division of the fertilized egg occurs about 3 weeks
after fertilization or 5 weeks after pollination. In the pecan N. C.
Woodroof (50) reports the first division of the egg at 8 to 9 weeks
after pollination, and Shuhart (33) 3 to 4 weeks.
878 YEARBOOK, 1937
Nast (22) found that the complete development from the megaspore
mother cell to the one-celled embryo in the Persian walnut, Juglans
regia, occurs within 7 to 12 days, depending on the season and climatic
conditions. Fertilization of the ovule was found to take place 2 to 5
days after pollination.
In the Manchurian walnut Juglans mandshurica, it is reported by
Langdon (20) that the megasporocytes pass through the different
phases of meiosis within 3 to 4 days and the embryo sacs are in one of
the earlier stages of nuclear division at the time of pollination. After
pollination from 4 to 5 days are required for the pollen tubes to reach
the embryo sacs, and fertilization of the eggs occurs 1 day later. She
found that the fertilized eggs had not divided 12 days after pollination
but in material collected 5 days later or 17 days after pollination four
8-celled embryos were present.
Chromosome counts have been made for a number of the nut-
producing species, and these are given in table 1, in the appendix.
Incompatibility
Except in the almond and the filbert, incompatibility, or inability
of male and female cells to unite and form a fertilized egg that can
grow to maturity, has not been definitely shown to exist between
individuals within a variety, or between different varieties, or between
species of the same genus of the nut-producing plants of the United
States.
Tufts and Philp (41 ) found that at least in certain years all almond
varieties studied were self -sterile. Of many thousand reciprocal crosses
made by them, only the IXL X Nonpareil and Languedoc X Texas
seemed to show distinct evidence of incompatibility or intersterility.
The parentage of almond varieties now grown in the United States is
unknown, and it is therefore not possible to determine whether rela-
tionship is a factor in this incompatibility between varieties. Since
these few cases of intersterility have been definitely established, it is
reasonable to assume that future investigations will disclose further
instances of this kind.
In some cases chestnut trees, particularly of the American sweet
species, Castanea dentata, that grow at a distance from others have
been observed to yield unsatisfactory crops or are unfruitful, although
producing staminate and pistillate flowers. Such trees apparently
require cross-pollination to insure fruitfulness. This is especially true
on the Pacific slope, where isolated trees that are fruitful are said to be
rare. Stout (37) reports observations made on two chestnut trees
growing apart from each other at Claremont, Calif., in which the trees
were heavily loaded with burs, but those of one tree contained only
shriveled nuts without kernels or embryos, and in the several bushels
of burs from the other tree there were only about 30 nuts that con-
tained kernels.
Self-unfruitfulness in the chestnut, especially the American species,
may be due to either self-incompatibility or to dichogamy. The former
condition is indicated by the report of Powell (26) in which he suggests
that the pistillate flowers are probably pollinated by the staminate
blossoms produced on long, slender axillary catkins, which blossom
first, and also by those that are produced at the distal end of the pistil-
NUTS 879
late catkin and blossom later. He also reports having noticed that
most of the stigmas of both European and Japanese varieties are
receptive while the early staminate flowers are in bloom.
Schuster {32) found that all varieties of filbert investigated by him
are practically self-incompatible. While a planting of a single variety
will generally produce a few nuts, the quantity attaining maturity is
negligible in proportion to the number of pistdlate blossoms. Cross-
incompatibility was found to exist between a number of varieties.
As with the almond, the parentage of the varieties of filbert now grown
is uncertain, and therefore no correlation between relationship and
cross-incompatibility can be made. Schuster found Du Chilly, which
is of the species Uorylus avellana, to be cross-incompatible with
C. colurna. He also found C. columa to be nonreceptive to pollen of
either Barcelona or Nottingham, both of which are of the same species
as Du Chilly. Du Chilly and Barcelona were unfruitful when polli-
nated with V. calif ornica. Reed (1) reported that the filbert breeding
work of the late J. F. Jones showed that a large number of varieties
of the European filbert, C. avellana, were definitely unfruitful and none
were found to be fruitful when pollinated with pollen of Rush, C.
americana, but the reciprocals of these crosses were highly fruitful.
Reed {27) has reported successful pollination of Rush and Little-
page varieties of the American hazel with pollen of O. colurna, C.
maxima, and C. heterophylla.
Inheritance of Characters
Most if not all varieties of the nut-producing species as they are
grown in the United States are genetically in a complex heterozygous
condition. This is due to the fact that all varieties of certain species
are self-incompatible, requiring cross-pollination in order to set fruits ;
or they are dichogamous to a greater or less degree. Thus the nut-
producing species do not lend themselves to a study of the inheritance
of characters. In most cases several years' time must elapse from the
planting of the seed until the resulting seedling produces fruit, and
each plant at the time of fruiting requires a considerable area of land,
which greatly limits the number of individuals that can be grown
under uniform conditions. Nevertheless nut improvement through
breeding by hybridization and selection has tremendous possibilities
for those who have the inclination, the time, and the facilities to carry
on the work.
Very little is known regarding the inheritance of characters in any
of the nut-producing species. Some study of hybrids between varie-
ties has been made in the case of the almond, and of hybrids between
species in the case of the chestnut. Since 1923 the Bureau of Plant
Industry and the California Agricultural Experiment Station have
been cooperating in an extensive almond-breeding project. Although
the total number of almond trees grown in this project has been large,
the number of individuals from any one cross is too small to establish
definite genetic ratios with accuracy. However, many interesting
facts have been recorded. The factor for bitterness in the nut appears
to be present as a recessive in all varieties of sweet almond. In most
instances when two sweet varieties are crossed, about three-fourths
of the progeny will produce sweet nuts and the rest bitter nuts, giving
880 YEARBOOK, 1937
a genetic ratio of 3:1. In some crosses, however, the ratio is appar-
ently 1.5:1 or 1:1. Other ratios may be found as the breeding work
progresses. The factor for "red spider resistance" seems to be present
in some varieties and not in others. To date, red spider-resistant
progenies have resulted only from crosses involving Harriott, Eureka,
Golden, Nugget, Nonpareil, and Reams. In Jordan the factor for
hard shell seems to be dominant. The desirable factor of heavy bear-
ing and the undesirable one of double kernels come out strikingly in
Lewelling. From a practical standpoint the results to date show
that a prime prerequisite for successful improvement in the almond
by hybridization includes the discriminating selection of parents that
possess outstanding characters of merit.
Beginning in 1894 and continuing for many years, Van Fleet {4-2)
grew many chestnut seedlings from seeds produced by hybridizing
Castanea dentata, C. pumila, C. sativa, C. crenata, and varieties of
these species. Detailed records were not kept, but his work showed
certain things of great importance to the chestnut breeder. Hybrids
between the chinquapin, C. pumila, and the Asiatic chestnut, C.
crenata, often produced nuts the second year after planting the seed.
Apparently the habit of C. dentata of coming into bearing much later
appeared in hybrids between this species and C. crenata or C. sativa,
since they rarely set burs until they were 5 to 12 years old. Re-
sistance to chestnut blight, Endothia parasitica (Murr.) P. J. and
H. W. Anderson, was found only when the Asiatic chestnut was used
as a parent, and even then when either C. dentata or C. sativa was a
parent the progeny was susceptible. The chinquapin is measurably
resistant to blight, but when it was crossed with C. sativa or C. dentata
the progeny was readily susceptible. Detlefsen and Ruth (12) made
studies of various taxonomic characters in three generations of
chestnut trees resulting from C. dentata X C. crenata crosses made and
grown by George W. Endicott, of Villa Ridge, 111. The striking
variations shown by the progeny indicate that many factors are
concerned in the inheritance of the characters observed.
So far as is known, the only comprehensive attempt made to
improve the European filbert, Corylus avdlana, by hybridization was
by C. T. Brixey, of Gervais, Oreg., who grew about 5,000 seedling
trees, mostly from seeds produced by controlled cross-pollination.
Out of these, only one seemed worthy of propagation. He named
this Brixnut. Only first-generation seedlings were grown, and no
effort was made to determine the dominance or recessiveness of the
parental characters. Of approximately 2,500 controlled crosses made
in the East by Reed (27) in 1927 between varieties of this species,
because of cold injury only about 50 seedlings have survived. No
study of inheritance has been possible.
Reed (27) reports that hybrids between Corylus americana and C.
amllana seem to be much more hardy than the pollen parents and are
less inclined to sucker, more erect in habit of growth, more vigorous,
and more easily trained to tree form than are the pistillate parents.
The foliage of the trees is usually like that of the pollen parents, as
the leaves are thicker, darker, and stiffer than those of the pistillate
parents. The size, form, color, thickness of shell, and plumpness and
NUTS 881
appearance of kernel are much like those of the pollen parent. The
Rush variety, which was principally used as the pistillate parent, has
the highly undesirable character of not permitting training to a single
stem. The great majorityof'the hybrids yield satisfactorily to the
single-stem method of training.
Although hybridization of pecan varieties has been carried on for
several years by the Bureau of Plant Industry and by pecan growers,
very little is known about the inheritance of characters. In most
cases only first-generation hybrids have been grown; however, it
seems that in cases where one of the parents is susceptible to pecan
scab the progeny are likewise susceptible with few if any exceptions.
Furthermore, the character of a speckled seed coat, which is char-
acteristic of the variety Brooks, appears in most of the progeny in
which Brooks is one of the parents.
The only study known to the writers of inheritance of characters
in the genus Juglans is that of Babcock (4), who studied the inherit-
ance of the peculiar oaklike character of J. californica var. quercina
Babcock in progenies from controlled crosses. The first-hybrid
generation seedlings were all typical J. californica trees, and of 18
second hybrid generation seedlings grown, 12 were J. californica and
6 were J. californica var. quercina, or a ratio of 2:1. Later back-
crosses of the first generation on quercina gave approximately 1:1
segregation (unpublished). Because of a widespread belief that the
quercina type was the result of natural crosses between J. californica
and Quercus agrifolia Nee., many controlled crosses were attempted
between these species without any fruit being produced. Thus Babcock
concludes that the variety quercina probably originated as a mutation.
LITERATURE CITED
(1) Anonymous.
1924. northern nut growers in fifteenth annual session. amer.
, Nut Jour. 21: 36, 39.
(2) Adriance, G.
1931. FACTORS INFLUENCING FRUIT SETTING IN THE PECAN. Bot. GaZ.
91: 144-166, illus.
(3) Babcock, E. B.
1915. walnut mutation investigations. Natl. Acad. Sci. Proc. 1:
535-537.
(4)
1916. studies in juglans. in. Calif. Univ. Pubs., Agr. Soi. 2: 71-80,
illus.
(5) Bailey, L. H.
1917. chestnuts. Ilia Standard Cyclopedia of Horticulture, v. 2, pp.
742-746, illus.
(6) Bakhtadze, K.
1935. [chromosomes of the tung-oil trees.] Sovetsk. Subtrop. 6:
75, illus. [In Russian.]
(7) Benson, M.
1894. contribution to the embryology of the amentiferae. Linn.
Soc. London Trans. (2) Bot. 3: 409-424, illus.
(8) Billings, P. H.
1903. chalazogamy in carya olivaeformis. Bot. Gaz. 35: 134-135,
illus.
(9) Bisset, P.
1914. the james river walnut. . . Jour. Heredity 5: 98-101, illus.
(10) Darlington, C. D.
1928. studies in prunus, i and ii. Jour. Genetics 19: [213]-256, illus.
882 YEARBOOK, 1937
(11) Darlington, C. D.
1930. studies in riUJNUs, hi. Jour. Genetics 22: [65]-93, illus.
(12) Detlefsen, J. A., and Ruth, W. A.
1922. an orchard of chestnut hybbids. Jour. Heredity 13: 305-314,
illus.
(13) FORKERT, C.
1914. TWELVE TEARS' EXPERIENCE IN HYBRIDIZING PECANS. Natl. Nut
Growers' Assoc. Proc. 13: 28-30.
(14) Fuller, A. S.
1896. THE NUT CULTUEIST: A TREATISE ON THE PROPAGATION, PLANTING
AND CULTIVATION OF NUT-BEARING TREES AND SHRUBS, ADAPTED
TO THE CLIMATE OF THE UNITED STATES. 289 pp., illus. New
York.
(15) Graner, E. A.
1935. NOTES ON THE CHROMOSOME NUMBER AND MORPHOLOGY IN ROOT
TIPS OF TUNG (ALEURITES FORDII, HEMSL.). Arch. Inst. Biol.
Vcg. 2: 81-82, illus.
(16) Heiges, S. B.
1896. NUT CULTURE IN THE UNITED STATES. 144 pp., illus. U. S. Dept.
Agr., Div. Pomology (unnumbered pub.).
(17) James, S. H.
1895. a pecan grove in Louisiana, a promising industry. Rural
New Yorker 54: 258-259.
(18) Jaretzky, R.
1930. zur zytologie der fagales. Planta, Arch. Wiss. Bot. 10: [120]-
137, illus.
(19) Kobel, F.
1927. zytologische untersuchungen an prunoideen und pomoideen.
Arch. Jul. Klaus-Stift. Vererbungsforsch. Sozialanthropol. Ras-
senhvg. 3: 1-84, illus.
(20) Langdon, L. M.
1934. EMBEYOGENY OF CARYA AND JUGLANS, A COMPARATIVE STUDY. Bot.
Gaz. 96: 93-117, illus.
(21) Lelong, B. M.
1897. California walnut industry. Calif. State Bd. Hort. Rept. 5:
77-120, illus.
(22) Nast, C. G.
1935. morphological development of the fruit OF JUGLANS EEGIA
Hilgardia 9: 345-362, illus.
(23) Nebel, B. R.
1931. cytological aspects of breeding nuts. North. Nut Growers'
Assoc. Proc. 22: 22-24.
(24) Okabe, S.
1927. cytological studies on prunus (a preliminary note). Bot.
Mag. [Tokyo] 41: 398-404, illus. [In Japanese. English
resume, p. 404.]
(25)
1928. zur cytologie dee gattung prunus. Tfihoku Imp. Univ. Sci.
Rept. 3: 733-743, illus.
(26) Powell, G. H.
1898. THE EUROPEAN AND JAPANESE CHESTNUTS IN THE EASTERN UNITED
states. Del. Agr. Expt. Sta. Bull. 42, 35 pp., illus.
(27) Reed, C. A.
1936. new filbert hybrids. Jour. Heredity 27: 427-431, illus.
(28) Rehder, A.
1927. manual of cultivated trees and shrubs hardy in north
america, exclusive of the subtropical and warmer tem-
PERATE regions. 930 pp., illus. New York.
(29) Risien, E. E.
1914. tree breeding. Natl. Nut Growers' Assoc. Proc. 13: 30-33,
illus.
(30)
1923. autobiography of a texas pecan pioneer. Amer. Nut Jour. 18:
48-49, illus.
NUTS 883
(31) Robbins, W. W., and Ramaley, F.
1933. plants useful to max. 428 pp., illus. Philadelphia.
(32) Schuster, C. E.
1924. filberts. Oreg. Agr. Expt. Sta. Bull. 208, 39 pp., illus.
(33) Shuhart, D. V.
1932. MORPHOLOGY AND ANATOMY OF THE FRUIT OF HICORrA PECAN.
Bot. Gaz. 93: 1-20, illus.
(34) Smith, C. L., and Romberg, L. D.
1932. POLLINATION CONTROL, PERIOD OF RECEPTIVITY AND POLLEN
viability in the pecan. Natl. Pecan Assoc. Bull. 31: 83-87,
illus.
(35) and Romberg, L. D.
1933. FURTHER STUDIES ON PERIODS OF RECEPTIVITY AND POLLEN VIA-
BILITY in the pecan. Natl. Pecan Assoc. Bull. 32: 49-55.
(36) Smith, R. E., Smith, C. O., and Ramsey, H. J.
1912. walnut culture in California, walnut blight. Calif. Agr.
Expt. Sta. Bull. 231, pp. [119]-398, illus.
(37) Stout, A. B.
1926. why are chestnuts self-fruitless? Jour. N. Y. Bot. Gard.
27: 154-158, illus.
(38) Taylor, W. A.
1905. promising new fruits. U. S. Dept. Agr. Yearbook 1904: 399-
416, illus., 1905; 1908: 473-490, illus., 1909.
(39) and Gould, H. P.
1914. promising new fruits. U. S. Dcpt. Agr. Yearbook 1913: 109-124,
illus.
(40) Traub, H. P., and Romberg, L. D.
1933. methods of controlling pollination in the pecan. Jour.
Agr. Research 47: 287-296, illus.
(41) Tufts, W. P., and Philp, G. L.
1922. almond pollination. Calif. Agr. Expt. Sta. Bull. 346, 35 pp.,
illus.
(42) Van Fleet, W.
1914. chestnut breeding experience . . . Jour. Heredity 5: 19-25,
illus.
(43) ■
1920. CHESTNUT WORK AT BELL EXPERIMENTAL PLOT. North. Nut
Growers' Assoc. Proc. 11: 16-21.
(44) Wetzel, G.
1929. chromosome^nstudien BEi den faoales. Bot. Arch. 25: [257]-
283, illus.
(45) Wood, M. N.
1924. almond varieties in the united states. U. S. Dept. Agr.
Bull. 1282, 142 pp., illus.
(46)
1934. POLLINATION AND BLOOMING HABITS OF THE PERSIAN WALNUT IN
California. U. S. Dept. Agr. Tech. Bull. 387, 56 pp., illus.
(47) Woodroof, J. G.
1924. THE DEVELOPMENT OF PECAN BUDS AND THE QUANTITATIVE PRODUC-
TION of pollen. Ga. Expt. Sta. Bull. 144, pp. 134-161, illus.
(48)
1930. STUDIES OF THE STAMINATE INFLORESCENCE AND POLLEN OF HICORIA
pecan. Jour. Agr. Research 40: 1059-1104, illus.
(49) Woodroof, N. C, and Bailey, J. E.
1928. unfruitfulness of the pecan. Ga. Expt. Sta. Bull. 148, 40
pp., illus.
(50) Woodroof, N. C.
1928. development of the embryo sac and young embryo OF HICORIA
pecan. Amer. Jour. Bot. 15: 416-421, illus.
(51) Woodworth, R. H.
1929. CYTOLOGICAL STUDIES IN THE BETULACEAE. II. CORYLUS AND ALNUS.
Bot. Gaz. 88: 383-399, illus.
(52)
1930. meiosis of microsporogenesis in the juglandaceae. Amer.
Jour. Bot. 17: 863-869, illus
884 YEARBOOK, 1937
APPENDIX
Table 1. — Number of somatic chromosomes in certain nut-producing plants
Common name
Almond
Chestnut:
American...
Spanish.-.
Filbert
Giant
Hazelnut:
American
Tree
Beaked
Japanese
Tibetian-..
Hickory:
Bitternut
Mockernut
Pecan
Pignut
Shagbark _.
Shellbark.
Sweet pignut- ..
Walnut:
Black
Butternut-
California black
Do...
Japanese
Manchurian
Persian
Texas
Heartnut
Tung
Scientific name
Amygdalus communis
Costarica dentate
Castanea saliva
Corylus avellana _._
Corylus avellana var. pontka
Corylus maxima
Corylus americana
Corylus colurna
Corylus heterophylla
Corylus rostrata _
Corylus sieboldiana
Corylus libttica
Hkoria cordiformis
Hicoriaalba
Hicoria pecan
Jlkoria glabra
Hicoria ovata
Uicoria laciniosa
Hicoria ovalis
Juglans nigra - _-_ _
Juglans cinerea
Juglans catifornka...
Juglans californica var. quercina.-.
Juglans sieboldiana
Juglans mandshurka
Juglans regia
Juglans rupeslris ___
Juglans sieboldiana var. cordiformis
Aleurites cordata
Aleurites fordii
Somatic
chromo-
some num-
ber (2n)
24
24
2 28
28
■<2»
i28
28
28
'28
28
28
32
64
» 20-24
64
32
32
64
<32
32
34
34
32
32
* 32
32
32
22
22
Authority1
(10,11,10,
U, 25)
08)
(IS)
(SI)
(SI)
(SI)
(St)
(SI)
(51)
(SI)
(SI)
(61)
(M)
(62)
(SO)
(SSI)
(SI)
(S2)
(52)
(61)
(61)
(S)
(3)
(62)
(6S)
(62)
(62)
(62)
(6)
(«, 15)
1 Reference is made by number to Literature Cited, p. 957.
2 Woodworth (61) reports: "Three pairs of the gemini commonly fuse completely, so that the metaphase
plate appears to have eight small chromosomes and three large ones.'* In view of this fact Wetzel (U) and
jaretzky (18) reported only 11 chromosomes as the haploid number.
3 Because of the small size of the chromosomes the number has not been definitely determined; most
probably the base number is the same as for the family.
' Nebel (28) reports that the somatic chromosome number in J. regia, J. nigra, and one J. nigra X regia
Fi hybrid is 34.
Table 2. — Nut species now being bred, locations, institutions, workers, and methods
Species
Location
Institution
Workers
Method'
Sacramento and Davis,
Calif.
Newberg, Oreg
Sydney, Australia
Beltsville, Md _..
U. S. Department of
Agriculture and State
Agricultural Experi-
ment Station.
Milo N.Wood
A.B. Scherf
S, 11
s
Department of Agricul-
ture, New South Wales.
U. S. Department of Agri-
culture.
State Agricultural Experi-
ment Station.
p
Butternut
H. L. Crane, J. W.
McKay, C. A. Beed.
S, II
s
Litchfield, Conn
Ithaca, N. Y
s
do
S. H. Graham
C.F.Walker
Carl F. Weschcke
G. A. Zimmerman
s
do.—
s
St. Paul, Minn
do. .
s
Harrisburg, Pa
do
s
1 S=selection, H=hybridization.
NUTS
885
Table 2. — Nut species now being bred, locations, institutions, workers, and methods-
Continned
Species
Location
Institution
Workers
Method
Chestnut ---
Glenn Dale, Md
Beltsville, Md .
U.S. Department of Agri-
culture.
do
R. B. Clapper, G. F.
Gravatt.
H.. L. Crane, J. W.
McKay, C. A. Reed.
A. S.Colby
H
S, H
State Agricultural Experi-
ment Station.
H
Ettersburg, Calif
Godfrey, 111
Albert Etter ...
S
...do—
S
— do— .
H. F. Stoke
S, H
. ...do.
G. A. Zimmerman.
II. L. Crane, J.
McKay, C. A. Re
S
Filbert
Beltsville, Md
Corvallis, Orcg. .- -
St. Paul, Minn
U.S. Department of Agri-
culture.
do __
State Agricultural Experi-
ment Station.
..do...
W.
ed.
S, H
S, H
W. H. Alderman, Ernest
Angelo, W. G. Brierly,
F. 15. llarolson.
S
S, H
C. T. Brixcy
S, H
Washougal, Wash— ._
do— :
D. Fitzgerald
S
do—
S, H
...do
A. M. Seherf.. _
S
College Park, Md .. .
Glenn Dale, Md
Beltsville, Md
do
0. P. Close .
s
do
U. S. Department of Agri-
culture.
State Agricultural Experi-
ment Station.
do—
J. J. T. Graham
8
Hickory
H. L. Crane, J. W.
Kay, C. A. Reed
A.S.Colby
Mc-
8
S
Geo. L. Slate-
s
do—
s
Litchfield, Conn
Ithaca, N. Y
s
do—
S. H. Graham
J. W. Hershcv
s
Downingtown, Pa
Kent, Ohio _. ...
do-
do—
s
Homer L. Jacobs _. ...
Mildred M. Jones.
J. Russell Smith.
8
do—
s
Swarthmore, Pa
Center Point, Iowa
do
do
s
Snyder Bros., Inc.
0. F. Walker
8
do
s
do—
O. A. Zimmerman.
H. L. Crane, J. W.
Kay, C. A. Reed
F. N. Dodge
s
Beltsville, Md. ..
U.S. Department of Agri-
culture.
do
Me-
S, H
H
do
Max li. Hardy, Harry
Lutz.
C. L. Smilh
H
do..
H
State AgriculturaJ Experi-
ment Station.
A.S.Colbv
S
Shattuc, 111
J. G. Duis
S
O'Fallon, 111
do—
S
do
II. C.Neville
s
do
8
do—
J. Tiedke
S
do
J. F. Wilkinson
S
Sydney, Australia
Mexico, D. F
Gainesville, Fla
Tifton, Ga
Department of Agricul-
ture, New South Wales.
Secretariat of Agriculture,
Department of Stations
and Experimental Fields.
State Agricultural Experi-
ment Station.
Georgia Coastal Plain Ex-
periment Station.
State Agricultural Experi-
ment Station.
U. S. Department of Agri-
culture.
State Agricultural Experi-
ment Station.
do
. do-
H. Wenholz
S
s
Tung
s
S
Baton Rouge, La
Beltsville, Md...
W. D. Kimbrough
U..L. Crane, J. W.
Kay, C. A. Heed
A.S.Colby.-
s
Walnut, East-
ern Black.
Mc-
S, H
s
St. Paul, Minn -
W. n. Alderman, Ernest
Angelo, W. G. Brierly,
F. E. Harolson.
s
s
Wooster, Ohio. ... ..
....do -.
s
Gilbert Becker . .
N. F. Drake
S ,G. Duis
i s
Shattuc, 111
0' Fallon, 111
....do
....do
do
s
s
s
Ithaca, N. Y
Eldora, Iowa. .
Godfrey, 111
Swarthmore, Pa. . ...
do
do
S. H. Qraham
s
E. F. Huen
s
do
s .
do
J. Russell Smith
s
886
YEARBOOK, 1937
Table 2. — Nut species now being bred, locations, institutions, workers, and methods-
Continued
Species
Location
Institution
"Workers
Method
Roanoke, Va
Private...
do
H. F. Stoke
S
0. F. "Walker
s
Continued.
Cincinnati, Ohio..
St. Paul, Minn
do
do
Harry K. Weber.
Carl P. Wesohoke
G. A. Zimmerman
H. L.Crane, J. W. Mc-
Kay, C. A. Heed.
"W. C. Deming
J. U. Gellativ
s
S
Ilarrisburg, Pn
Beltsville, Md
Litchfield, Conn
Westbank, B. C
Downingtown, Pa
Lancaster, Pa .
Wassaic, N. Y
do
s
V. S. Department of Agri-
culture.
S, H
S
do
S, 11
"y/.Aoiv////"".'.'.'.'.'.'.'.'.'.'.
do
J. "W. Hershey.
Mildred M. Jones
Gilbert L. Smith
Ross Pier Wright
s
s
s
Westfield, N. Y
Corvallis, Oreg ...
St. Paul, Minn
Geneva, N. Y .
Roseburg, Oreg
do
U. S. Department of Agri-
culture.
State Agricultural Experi-
ment Station.
State Agricultural Experi-
ment Station.
Private
Secretariat of Agriculture,
Department of Stations
and Experimental Fields.
s
S, 11
W. 11. Alderman, Ernest
Angelo, W. G. Brierly,
P. E. Ilarolson.
Goorge L. Slate. ... .
C. E. Moyer . . ...
G. Gandara
II
H
S, H
8
Table 3. — Varieties of nuts of probable value for breeding
Genus, species, variety,
and region
Origin or introducer
Comments
Amygdalm comma nis:
Drake
Eureka..
IXL....
Ne Plus Ultra.
Nonpareil
Texas
Corylus:
White Aveline.
Barcelona...
Brixnut
Du Chilly...
Italian Red.
Littlepage...
Rush
Winkler
Hkoria (exclusive of pe-
can) :
Anthony (probably
II. ovata).
Berger (probably II.
laciniosa'X. alba) .
Chase (probably II.
ovata).
Coleman (probably
FI. ovata).
Davis (probably IT.
ovata).
Emcrick (probably
I-I. ovata) .
Fox (probably II.
ovata).
Goheen (probably
H. ovata).
Hagen (probably H.
ovata).
'Deceased.
California .
do
do
.do
-do_
-do.
Long a standard; fr^m Europe.
-do_
C. T. Brixey, Gervais, Oreg
Long a standard ; from Europe-
Long well known; from Europe.
Thomas P. Littlepage, Bowie, Md
J. G. Rush.i Pennsylvania
Snyder Bios., Inc., Center Point, Iowa.
A. B. Anthony, Sterling, 111
Russell Berger, Cove Gap, Pa
W. R*. Chase, Hartford, Conn
Mrs. Thomas Coleman, Saltsburg, Pa.
Dwight Davis, Dover Plains, N. Y
Etta Emerick, West Camp, N. Y
Roland D. Fox, Fonda, N. Y
Mrs. Martha Goheen, Pennsylvania
Furnace, Pa.
Mrs. C. E. Ilagen, Quttenberg, Iowa. .
Of chief value because of prolificacy and
usefulness as a pollinizer.
Highly prolific, with small but very
sweet nuts.
Long one of California's most valuable
varietios.
Do.
Do.
A heavy bearer, considerably like
Drake.
Shell very thin; kernel of finest quality
and flavor.
Leading variety of Pacific Northwest.
Large nut; very prolific.
Long a chief variety in Pacific North-
west.
Has given good results in eastern
breeding.
A highly prolific native from southern
Indiana.
A native found highly useful in breed-
ing.
Best native variety yet found in State.
An excellent nut.
First prlzemisccllaneous hickories, 1934
contest, Northern Nut Growers' As-
sociation.
An excellent nut.
Third prize, 1934 contest, Northern
Nut Growers' Association.
First prize, 1934 contest, New York
State.
Superior cracking quality.
First prize, 1934 contest, Northern Nut
Growers' Association.
Second prize, 1934 contest, Northern
Nut Growers' Association.
One of the best known in the State.
NUTS 887
Table 3. — Varieties of nuts of probable value for breeding — Continued
Genus, species, variety,
and region
Origin or introducer
Comments
Ilicoria (exclusive of pe-
can)— Continued.
Heibuer (probably
II. ovata).
Jolliffo (probably H.
ovata).
Lawson (probably
/-/. ovata).
Mann (probably It.
ovata).
Miller (probably II.
ovata).
Redcay (probably
H. tacimosa).
Komig (probably II.
ovata).
Sande (probably II.
ovata).
Swaim (probably II.
ovata).
Vest (probably II.
ovata).
Whitney (probably
II. ovata).
"Wilcox (probably //.
ovata).
Ilicoria pecan:
Southeastern region:
Brake
Brooks
Candy
Curtis
Desirable-
Lewis
Mobile
Moneymaker.
Moore
Nelson __
Russell..
Schley...
Stuart...
Success. _
Southwestern region:
Burkett
Clark
Halbert
Nugget..
San Saba Im-
proved.
. Sovereign
Squirrel... _.
Supreme
Western
Northern region:
Busseron
Clarksvillc.
Dewitt
Duley
Elmer
Fisher
Oallatin
Goforth
Greenriver.
Harmon.
Harvey A. Ueibner, Danville, Iowa
George C. Jollifle, Ufflngton, W. Va...
Donald Lawson, Dorloo, N. Y__
Mrs. Rae D. Mann, Davison, Mich—..
D. P. Miller, North Branch, Mich
Adam Kedeay, Lititz, Pa...
RomigBros.,Downington, Pa..
Elmer T. Sande, Story City, Iowa
II. II. Swaim & Son, South Bend, Ind.
Luther \V. Vest, Blaeksburg, Va
\V. O. Whitney, Berca, Ohio
P. E. Wilcox, Geneva, Ohio
William II. Brake, Rocky Mount,
N. C.
B. W. Stone, Thornasville, Ga
Theodore Bechtel,1 Ocean Springs,
Miss.
J. B.Curtis,! Orange Heighls, Fla
C. Forkert,' Ocean Springs, Miss.
F.n. Lewis,' Pascagoula, Miss
B. W. Stone, Thornasville, Ga.. .
S. H. James,' Mound, La
Severalnurserymen, Monticello, Fla..
William Nelson, i New Orleans, La
II. F. Russell,' Ocean Springs, Miss...
A . G. Delmas,' Pascagoula, Miss
W. R. Stuart,1 Ocean Springs, Miss...
Theodore Bechtel,' Ocean Springs,
Miss.
J. H. Burkett, Clyde, Tex
William Millican, Bend, Tex
H. A. Halbert,' Coleman, Tex
J. A. Evans, Arlington, Tex
E. E. Risien k Son, San Saba, Tex..
.do.
.do.
.do.
.do.
Long a standard; from near Vincennes,
Ind.
Arthur L. Norton, Clarksviile, Mo...
George F. Dewitt, Butler, Mo
John Duley, New navon, 111
Snyder Bros., Inc., Center Point, Iowa
Joseph Gerardi, O'Fallon, HI
C. w. Richardson, New Haven, 111...
Bert Goforth, New Haven, 111
Standard variety; Daviess County,
Ky.
Anna S. Harmon, Mount Carmel, 111.
Very superior nut.
Very high percentage of kernel.
Second prize, 1934 contest, New York.
First prize, 1932 contest, Michigan.
Second prize, 1932 contest, Michigan.
Second prize, miscellaneous hickories,
1934 contest. Northern Nut Growers'
Association.
An excellent nut-
One of best known in Iowa.
Highly prolific.
Extremely thin shell.
First prize, 1934 contest, Ohio.
Second prize, 1934 contest, Ohio.
Outstanding cracking and kernel qual-
ity.
Scab-resistant; prolific; superior crack-
ing quality.
Superior table variety; roundish.
Scab-resistant; superior cracking and
kernel quality.
Large size; scab-resistant; good crack-
ing quality.
Do.
Prolific; scab-resistant.
Prolific; early to mature.
Prolific; scab-resistant; early; good
cracking quality.
Prolific; vigorous; scab-resistant.
Scab-resistant; very thin shell; sweet.
Thin shell: very superior kernel quality.
Scab-resistant ; of good commercial size.
One of the best: when good ; variable.
Very fine table variety.
Very fine all-around variety.
Extremely precocious and prolific.
Superior shelling quality.
Notably thin shell.
Notably prolific.
Notable flavor.
Generally very fine variety.
Do.
Matures early; no other advantage.
One of the most northern in origin.
Superb cracker; high percentage kernel.
Very good all-around nut.
Should be one of the most hardy.
Said to be unusually prolific.
One of the most promising new varie-
ties.
First prize, 1934 contest, Northern Nut
Growers' Association.
Best of older northern varieties.
An excellent seedling, not yet prop-
agated.
' Deceased.
888
YEARBOOK, 1937
TAnr.E 3.— Varieties of nuts of probable value for breeding— Continued
Genus, species, variety,
and region
Origin or introducer
Comments
Hicoria pecan— Gontd
Northern ■ region
Continued.
ITofmann __
Indiana
Kentucky
Major
Meyer
Niblack
Norton
Posey
September
Juglam cinereu:
Aiken
Alverson
Baker
Buckley
DoVan
llostetter
Irvine
Kenworthy
Lingle
Love
Luther
Mitchell....
Robinson
Sherwood
Smith _
Thede.
Thill _
Utter back _
Wright..
Juglam nigra:
Adams.
Allen
Asbury-
Benton
Booth _
Brown _
Clark _.
Cowle
Creitz
Creseo..
Dougherty _
Edge-wood
Edmunds
Edras
Franklin
Free!
Grundy
Hepler _
Impit..
Janson _
Kettler
Knapke...
Learn
Lee
0. J. Hofmann, Henderson, Ky
Long a standard; 300 yards from orig-
inal Busseron.
Long a standard; northern Kentucky.
Longastandard; Daviess County, Ky_
Mrs. Tony Meyer, Brunswick, Mo...
M. J. Niblack,1 Vincennes, Ind
Arthur L. Norton, Clarksville, Mo
Long a standard; southwestern Indi-
ana.
J. F. Wilkinson, Rockport, Ind
J. F. Jones Nurseries, Lancaster, Pa_.
M. E. Alverson, Howard City, Mich..
G. A. Zimmerman, Harrisburg, Pa
Park Buckley, Strawberry Point, Iowa.
V. E. DeVan, Rock Creek, Ohio
O. F. Hostetter, Bird in Hand, Pa
L. K. Irvine, Menomonie, Wis.
John F. Kenworthy, Rockton, Wis...
E. J. Lingle, Pittsfield, Pa
Charles P. Reed, Howell, Mich
F. Luther, Fairgrove, Mich
Claude Mitchell, Scotland, Ontario,
Canada.
Mrs. Ada Robinson, Waterman, 111...
Snyder Bros., Inc., Center Point, Iowa.
Horace T. Smith, Chicopee, Mass
M. F. Thede, Wayland, Mich.. _
M.J. Thill, Bloomer, Wis
W. E. Utterback, Sigourney, Iowa
Douglas N. Wright, Colchester, Vt
R. Adams, Scotts, Mich
Glenn W. Allen, Middleville, Mich...
C. D. Asbury, Augusta, Ky
W. A. Benton, Wassaic, N. Y _
R. A. Booth, Bonsack, Va
Mrs. Willard Brown, Rock Bridge,
Ohio.
Frank Clark, Lamoille, Minn
B. A. Cowle, Defiance, Ohio..
W. A. Creitz, Cambridge City, Ind...
W. A. Bents, Creseo, Iowa
L. D. Dougherty, Crane, Mo
Ben F. Walker, Siloam Springs, Ark..
Lewis Edmunds, Glasgow, Ky._ _
Gerald Adams, Moorhead, Iowa.
G. A. Zimmerman, Harrisburg, Pa
Mrs. E. W. Freel, Pleasantville, Iowa.
John Rohwer, Grundy Center, Iowa..
George Y. TIepler, South Bend, Ind...
J. U. Gellatly, Wcstbank, British Co-
lumbia, Canada.
W. W. Janson, Jefferson, Ohio
Fred Kettler, Platteville, Wis _
J. J. Knapke, New Weston, Ohio
Dane Learn, Aylmcr, Ontario, Canada
R. £. Lee, Troutville, Va
An excellent seedling, not yet propa-
gated.
Matures early; no other advantage.
Excellent midseason pollinizer.
Excellent nut, but too small and round.
Should be hardy well north.
Best cracking quality; very sweet.
Large nut; should be hardy north.
Handsome tree; excellent cracker.
Said to be earliest to mature.
From New Hampshire; small but good
cracker.
Third prize, 1932 contest, Michigan.
From New York; highly promising.
One of best known in Iowa.
Fifth prize, 1920 contest, Northern Nut
GroweTs' Association.
Third prize, 1929 contest, Northern
Nut Growers' Association.
First prize, 1929 contest, Northern Nut
Growers' Association.
Fourth prize, 1929 contest, Northern
Nut Growers' Association.
Sixth prize, 1929 contest, Northern Nut
Growers' Association.
One of best known in Michigan.
Second prize, 1932 contest, Michigan.
First prize, 1932 contest, Michigan.
One of best known in Illinois.
One of best in State.
One of best known in Massachusetts.
One of best known in Michigan.
Second prize, 1929 contest, Northern
Nut Growers' Association.
One of best in State.
One of best known in State.
Highly rated by U. S. Department of
Agriculture and Michigan Agricul-
tural Experiment Station.
Do.
Third prize, 1926 contest, Northern
Nut Growers' Association.
Second prize, 1934 contest, New York.
Excellent cracking and kernel qualities.
First prize, 1933 contest, Ohio.
Fourth prize, 1934 contest, Northern
Nut Growers' Association.
Third prize, 1933 contest, Ohio.
Excellent cracking and kernel qualities.
Very good nut; very hardy.
Very good nut; best for southern lati-
tudes.
Do.
First prize, 1934 contest, Northern Nut
Growers' Association.
High percentage of excellent kernel.
Good nut; blooms very late.
First prize, 1929 contest, Northern Nut
Growers' Association.
First prize, Iowa State Fair, 1927.
E xcellent crack ing and kernel qualities.
For consideration in Pacific Northwest.
Fourth prize, 1933 contest, Ohio.
Excellent nut; should be hardy in
North.
Excellent nut; high percentage of
kernel.
Very white kernel; very sweet; hardy.
One of best yet found in Virginia.
NUTS 889
Tabjje 3. — Varieties of nuts of probable value for breeding — Continued
Genus, species, variety,
and region
Origin or introducer
Comments
Jagtans nigra — Contd.
Lionberger
Marion-
McMillen...
McPherson..
Mintle
Monterey...
Mj'crs.-
Ohio.
Patterson..
Pinecrest..
Rohwer. . .
Sifford...
Snyder..
Sparrow..
Stabler...
Ten Eyck.
Thomas. __
Throp
Tritten
Waldsmith. ,
Wanda .
Wetzel.
Wiard.
Wright...
Juglans regia:
Concord. .
Crath Seedlings.
Ehrhardt..
Eureka
Franquette..
Payne
Plaeentia..
Jutjtnm skboldiana: 2
Hates (Hn)
Bourne (Hn)
Calendar (Hn)
Cardinell(S)....
Caruthers (FTn)_
English (S)
Kvers (Jin).
Faust (Hn).
Fodermaier (Iln).
King (Hn)
Lancaster (Hn).
Mitchell (Un)...
Stranger (In)
Wright (Hn)
Juglans sieboldiana hy-
brids:
Cording X J. regia..
Creitz X J. cinerea.
llelmkk X •/. cinerea.
John W. Lionberger, Table Rock,
Nebr.
Mrs. E. W. Freel, Pleasantville, Iowa.
Lowell McMillen, Buchanan, Mich...
A. McPherson, Jr., Caledonia, N. Y._
J. R. Mintle, Glenwood, Iowa
L. K. Hostetter, Lancaster, Pa
E. R. Myers, Bellefontaine, Ohio
J. F. Jones Nurseries, Lancaster, Pa..
Mrs. William Patterson, Wever, Iowa.
Herbert Miller, Richfield, Pa
John Rohwer, Grundy Center, Iowa..
C. L. Sifford, Buchanan, Va..
C. H. Snyder, Newfleld, N. Y
Harry C. Sparrow, Lomax, 111
Thomas P. Littlepage, Bowie, Md.
.T. F. Jones, Lancaster, Pa
J. W. Thomas & Sons, King of Prussia,
Pa.
Ralph Throp, Greensburg, Ohio
Sam Tritten, Lisbon, Ohio
L. 0. Waldsmith, Hartselle, Ala
Gerald Adams, Moorhead, Towa...
Annie M. Wetzel, New Berlin, Pa.
Everett Wiard, Ypsilanti, Mich
Herman Wright, Wolcolt, N. Y....
French parentage
Poland
South America-
Persia
France
....do
South America.
J. F. Jones Nurseries, Lancaster, Pa...
Fred Bourne, Milford, Mich
J. U. Gellatly, Westbank, British
Columbia, Canada.
Bob Cardinell, East Lansing, Mich...
A. Caruthers, Ferrell, Va
Harold English, Chatham, Ontario,
Canada.
A. H. Evers, Petoskey, Mich
J. F. Jones Nurseries, Lancaster, Pa..
John J. Fodermaier, Dover Plains,
N. Y.
John W. Hershey, Downingtown, Pa
J. F. Jones Nurseries, Lancaster, Pa-
Claude Mitchell, Scotland, Ontario,
Canada.
J. F. Jones Nurseries, Lancaster, Pa. .
Ross Pier Wright, Westfleld, N. Y...
R. Bates, Jackson, S. C
W. A. Creitz, Cambridge City, Ind__
James K. Helmick, Columbus Junc-
tion, Iowa.
Best yet found in State; very good mat.
First prize, 1929 contest, Northern Nut
Growers' Association.
E xcellent cracking and kernel qualities.
Third prize, 1934 contest, New York.
Unusually fine nut.
Excellent cracking and kernel qualities.
Unusually thin shell; very good other-
wise.
Standard variety since first propagated
in 1915.
Excellent cracking and kernel qualities.
Do.
Second prize, 1926 contest, Northern
Nut Growers' Association.
Excellent cracking and kernel qualities.
First prize, 1934 contest, New York.
Excellent cracking and kernel qualities.
Many nuts have single lobes; good
cracker.
Unusually thin shell.
Has long been the leading standard
variety.
Most or all have single lobes.
Second prize, 1933 contest, Ohio.
Best black walnut yet found in Ala-
bama.
Excellent cracking and kernel qualities.
Fourth prize, 1929 contest, Northern
Nut Growers' Association.
Third prize, 1934 contest, Northern
Nut Growers' Association.
Fourth prize, 1934 contest, New York.
Leading favorite in central portions of
California; blooms late.
Now being introduced by Paul C.
Crath, Toronto, Canada, in the hope
of finding greater hardiness.
A heavy bearer of high-grade commer-
cial nuts.
A leading commercial sort; blooms late;
nuts well sealed.
Late bloomer; leading commercial sort
of Pacific Northwest.
Very precocious and prolific.
The leading commercial variety in
southern California.
One of best yet tested.
Second prize, 1932 contest, Michigan.
Best variety from Pacific Northwest.
Third prize, 1932 contest, Michigan.
Best variety from Virginia.
First prize, 1932 contest, Michigan.
Second prize, 1932 contest, Michigan.
Exceptionally vigorous; good nut;
large.
Excellent nut; highly promising.
Do.
Standard; first variety propagated.
First prize, 1932 contest, Michigan.
Said not to be dichogamous.
Very new; apparently one of the best.
Extremely rapid grower.
Prolific; reasonably good.
Heavy bearer; quite good.
2 Hn=heartnut; S = Siebold walnut.
138904°— :?7- 57
IMPROVEMENT OF
FLOWERS BY BREEDING
S. L. EMSWEIXER, Principal Horticulturist,
PHILIP BRIERLEY, Associate Pathologist,
D. V. LUMSDEN, Associate Physiologist,
F. L. MULFORD, Associate Horticulturist,
Division of Fruit and Vegetable Crops
and Diseases, Bureau of Plant Industry
A<
lGRICULTURE is above all things practical, and probably few
people would think of it as concerned with the production of sheer
beauty. Yet American agriculture has $290,000,000 invested in pro-
ducing beauty, and it pays to the extent of a gross return of $131,000,000
Figure J.. — Approximate location of florists' establishments producing flowers and
plants grown under glass and flowers grown in the open, 1929.
a year. These figures apply to the farms and nurseries engaged in
growing flowers and ornamental plants, outdoors and under glass.1
The map (fig. 1) shows both how widespread the industry is and how
heavily it is concentrated in certain regions.
This great industry supplies material for the immense number of
people who grow flowering and ornamental plants for their own en-
joyment. During recent years there has been a rapid increase in the
1 In 1929, according to the census, there were 13,088 florists producing flowers and plants as a business, both
under glass and in the open. The number of commercial nurseries at that time was 7,207, and probably
most of these devoted at least part of their space and time to the production of ornamental plants. In
addition, 1,935 farms wore reported as engaged in growing bulbs commercially. The number of farms en-
gaged in producing seed of flowering plants— a well-developed industry on the Pacific coast, expecially in
California — was not included.
890
FLOWERS 891
planting of flowers around homes and in the planned planting of
streets, roadways, and parks. The large number of flower shows and
exhibits, ranging from the small display of a village garden club to
the huge annual national and international shows, is one evidence of
this interest. In some of these shows the competition for prizes for
new or improved strains or seedlings has become very intense, es-
pecially among fanciers of one kind of flower, such as the chrysan-
themum, dahlia, gladiolus, rose, or iris.
These demands of both florists and home growers have been the
major influence in the development of new and finer types of flowers,
and eachyear there are many new introductions. Undoubtedly chang-
ing fashions play a large part in this activity, and the florist must be
constantly on the alert to meet them.
BACKGROUND OF FLOWER BREEDING
It is likely that our early ancestors were too busy securing the bare
necessities of life to pay much attention to plants that had nothing
but their beauty to recommend them. Conscious selection of purely
decorative plants probably did not begin until some sort of stable
living conditions had been achieved. When early man first began to
grow flowers, he very likely transplanted entire clumps from the wild
to his dooryard. It is only natural that he should have chosen the
best for transplanting and thus practiced the first plant selection in
ornamentals. As time went on, the use of flowers and ornamental
plants played an ever-increasing part in his everyday life. We know
from the remnants of early art that flowers were regarded highly, since
so many of them furnished the chief motif in decoration.
The early records of selections and attempts to breed flowering
plants are very meager. Considerable work had undoubtedly been
done by the beginning of the eighteenth century. The first apparently
authentic record of hybridizing flowers, however, appeared m 1717,
when Thomas Fairchild's cross between a carnation and a sweet-
william was reported. This occurred during a period when consider-
able interest had been aroused by the work of Camerarius, who
demonstrated the existence of sex in plants.
The species hybrid produced by Fairchild was completely sterile
and was commonly referred to as the plant mule. The chief interest
of the botanists of this period was not so much the production of better
plants as the accumulation of evidence on sexuality in the plant king-
dom. Fairchild's hybrid, however, received considerable attention
and was described in 1717 in Bradley's New Improvements in Planting
and Gardening, as being neither sweet-william nor carnation, but as
resembling both equally.
Work of Amateur and Professional Breeders
After the existence of sex in plants had been generally accepted, it
is probable that countless amateurs carried on some sort of breeding
work with flowers. The development of many new varieties and
strains during the nineteenth century indicates the wide interest in
this type of work. Even at the present time many of the new and
improved types of flowers are being produced by amateur breeders.
The work of the amateur is frequently done on a very small scale in
892 YEARBOOK, 1937
a back-yard garden. In the numerous organizations interested in
some one flower, such as the American Rose Society, the American
Iris Society, and others, there are many members engaged in the fas-
cinating hobby of flower breeding. A great deal of this work is never
heard of, but undoubtedly it has produced many of our present vari-
eties of such important flowers as iris, gladiolus, dahlia, rose, and
narcissus. It involves the making of many thousands of crosses each
year in a very wide range of plant material. In an article such as
this, it is obviously possible to mention the work of only a few amateur
breeders, and this is done here and there under sections dealing with
particular plants. It is likewise not possible to discuss all the numer-
ous varieties that have been developed by flower breeders. The fol-
lowing resume of the number of listed varieties of some of the groups
of the commoner flowers is evidence of the extent of interest in this
field.
Number of
Name varieties
Rose .. 15,000
Chrysanthemum 1, 500
Narcissus 3,000
Tulip 8,000
Sweet pea 500
Snapdragon 400
Aster . 600
Dahlia 7,000
Gladiolus. . 2,500
Iris -4,000
Peony 2,000
Since new varieties are constantly appearing and old ones going
out of fashion, the data of this tabulation can be accepted only as
approximations. The origin of most varieties of flowers is unknown,
and it is beyond the scope of this article to attempt to indicate this
for each kind of flowering or ornamental plant, but the named varieties
of the plants included in this discussion far exceed in number those
of our important food plants. It is safe to say that the production
of such a large number has been possible only because of the work of
thousands of amateur breeders, whose main compensation has been
the pleasure the work has afforded them.
The contributions of the professional breeders, including nursery-
men, florists, and seedsmen, are likewise very large. It is to the
work of this group that we owe the development of nearly all our
modern varieties of such important flowers as the rose, zinnia, sweet
pea, carnation, calendula, aster, snapdragon, larkspur, and nastur-
tium. While it is true that profit has been a primary factor in this
work, the professional breeder almost always has an inborn love for
the plants and flowers that are his stock in trade.
Practically all the large flower-seed growers are carrying on exten-
sive breeding programs. Of the many new flowers or so-called novel-
ties introduced to the public each year, some have arisen as recom-
binations following chance crosses that occurred in the fields in
previous years, and a very few may be spontaneous mutants, but most
are the result of selections within lines that are mixed or not genetically
pure in their ancestry (fig. 2). The opportunity for such selection
on a large flower-seed farm is very great. It is not unusual, for
FLOWERS 893
instance, to see as many as 5 acres of some one flower, with as many as
430,000 individual plants. This means that the possibility of finding
rare multiple recessives is fairly great. Here it is not a question of
following the inheritance of one or a few genes. The trainee! geneticist
has an opportunity to find nearly every combination of characters
that could possibly arise from the material (fig. 3).
Figure 2. — Variation in hollyhock flowers collected from a group of plants growing in
a garden at Davis, Calif. By selection and by controlling pollinations for several years
all but the double form could probably be made to breed true. The double shown
here is a rather complex form thai cannot be bred to come true from seed.
When a new outstanding type appears in a field it is usually recog-
nized. If it seems desirable, a stake is placed beside it and the seed
is collected as it matures. In recent years the more careful growers
take measures to protect the selected plant against cross-pollination if
it is a species not normally self-fertilized (fig. 4). As many as several
thousand such field selections may be made each year on a large
flower-seed ranch. Only the best variants are carried on, and these
are usually not introduced until they breed fairly true to type. While
undergoing this period of selection and reselection they are said to be
"in the shop" (fig. 5).
There is no doubt that the flower varieties of today are a vast
improvement over those of 15 to 20 years ago. Undoubtedly we owe
a real debt of gratitude to the amateur and professional breeders whose
efforts have made this possible. When it is recalled that most of this
work has been accomplished without the aid of a background of
knowledge of genetics, the possibilities for the immediate future are
indeed bright. In many instances the results coidd have been
accomplished in a much shorter period, and frequently a smaller
population of plants would have sufficed. Unfortunately there still
894
YEARBOOK, 1937
exist many erroneous ideas and beliefs among flower breeders. Some
of these will be discussed later in this article.
Need for More Scientific Methods
The accumulation of data and the development of fundamental
principles in genetics have gone on at a rapid pace during the last 25
years. As a result there is now available sufficient information prac-
* >1
Figure 3. — A field planting in ( California of annual larkspur for seed. There are several
hundred thousand plants in a field of this size. To many the plants would appear
uniform, but to a trained investigator there would be countless variants as to flower
shape, color shades, plant habit, foliage, and many other characters. (Courtesy
of Bodger Seeds, Ltd.)
tically to revolutionize the practices of the average amateur and pro-
fessional flower breeder. Unfortunately this material is not readily
accessible, being widely scattered in scientific journals and papers in
many different languages.
Much of the unfaniiliarity of flower breeders with this mass of
information is probably due to the fact that it has never been called
to their attention. For instance, geneticists have known for years
that the common flowering stocks (Matthiola incana (L.) R. Br.) were
limited to a maximum of about 56 percent of doubles and that no more
can be obtained; yet considerable money is being spent by florists
and seedsmen each year to breed strains that will produce "a higher
proportion.
No one would think of stepping into an airplane and attempting to
fly it without some preliminary instruction, yet apparently nearly
FLOWERS
895
everyone thinks the only requisite for success in flower breeding is a
liking for the work. If this article seems to be somewhat more tech-
nical than the reader might expect, considering the popular appeal of
the subject matter, it is because the authors believe the time has come
when those interested in improving flowers must be ready to put some
effort on studying the basic elements of their science. Planned breed-
ing is unquestionably a
fairly complex job. It
does not sit and wait
for the "breaks" but
goes out and makes
them. It has its rules
and principles, and he
who becomes familiar
with them is well re-
paid in increased effi-
ciency. Some of these
rules and principles
will be discussed in the
following pages.
Most of the early
technical investigators
who worked with
flowers were interested
mainly in establishing
fundamental principles
of inheritance. This
explains why, until
very recently, so few
varieties of flowers or
ornamentals have been
produced by technical
workers. Following
the rediscovery of
Mendel's work in 1900,
numerous experiments
were carried on to test
the validity of his laws.
In a goodly share of
these, some species of
flowering plant was
used as experimental material. As a result there was built up a con-
siderable amount of data on the inheritance of many characters in a
wide range of flowering plants. This has been summarized and is
presented in the appendix of this article.
Kecently the possibility of producing strains of flowers resistant to
diseases has been receiving more than usual attention. The achieve-
ments in this field with some plants such as wheat, sugar beets, cabbage,
etc., have stimulated a desire for similar work with flowers. The
control of many virus and fungus diseases of flowers is very difficult
and offers a challenge to the plant breeder. The success achieved with
wilt-resistant asters (fig. 6) and rust-resistant snapdragons is an
Figure 4. — A type of bag commonly used to protect se-
lected flower plants from cross-pollination. A stake is
driven into the ground close to the plant and a tin or
galvanized-iron cylinder open at bolh ends is placed
around the base of the plant and stake. A long cloth
bag open at both ends is pulled down over the plant
and stake, tied tightly about the metal cylinder, and
closed at the top with a drawstring. This gives protec-
tion from insect visitors, and if mesh of cloth is fine
enough also from wind-blown pollen.
896
YEARBOOK, 1937
indication of the immense possibilities. In this type of work it is
very probable that technical workers in public-service institutions will
lead the way. A close cooperation between pathologists and geneti-
cists will be essential and is now provided in many experiment stations
and in the United States Department of Agriculture. Work in this
Figure 5. — A sweet pea "workshop" in California. Seed from controlled crosses is
planted in rows, and when plants are in bloom the breeder takes notes on each lot,
selecting the most desirable for further breeding. Three long bamboo stakes are placed
to form a tripod over each selected plant, and if seed is to be saved a little bag is
numbered and tied to the bamboo support. (Courtesy of Ferry-Morse Seed Co.)
field may become involved in difficulties, such as the sudden appearance
of other forms of a disease-producing organism that are able to infect
hitherto resistant plants. These so-called physiological strains of
fungi are discussed at some length in the section on wheat in the 1936
Yearbook of Agriculture. They will be mentioned later under the
discussion of rust resistance in snapdragons.
There is also a demand for types better suited to certain unfavorable
environmental conditions, such as winter cold, drought, or intense
heat. At the present tune practically all of the breeding work on
flowers is restricted to certain sections of the United States and of
Europe. It is very probable that some genetic material discarded as
undesirable in one region might be extremely valuable if grown under
a different set of environmental conditions. For instance, too glaring
FLOWERS
897
colors would very likely be less intense in a warmer, sunnier climate
and the washed-out pink of a hot region is apt to be about right in a
cooler habitat. Long, slender, weak stems in a warm section are
commonly shorter and sturdier when the plants are grown under
cooler conditions.
The effect of length of day on blooming is another very important
point that is now given scant consideration by the average flower
Figure 6. — Will-resislaiil and susceptible asters planted side by side on infested soil.
The susceptible plants on the right have been practically wiped out by the disease.
(Courtesy of Bodger Seeds, Ltd.)
breeder. When plants of a species known to be sensitive to day length
are selected for blooming at some particular time of year in one lati-
tude, it should be remembered that in another their behavior in this
respect is likely to be different.
The breeding of winter-hardy perennials is just now beginning to
receive some attention. Here also, results will depend to a considerable
extent on the location in which the plants are to be grown. Low atmos-
pheric temperatures are less destructive if there is a heavy blanket of
snow. This explains why some flowering perennials overwinter nicely
in Canada, but are frequently winter-killed in the Ohio Valley.
A very valuable aid in the breeding of flowers is the collecting of
new germ plasm by introducing species and varieties native to other
parts of the world. This has been done in this country chiefly by
the Division of Plant Exploration and Introduction, of this Bureau.
The many botanical gardens in all parts of the world also exchange
898 YEARBOOK, 1937
seeds and plant materials. While some of these introductions are
rather unattractive as measured by American standards, yet they
may carry very valuable genes. In many instances these "immi-
grant genes" can be introduced into some of our own standard
varieties, giving new and more desirable strains.
As a result of widespread interest and to stimulate greater effort,
American seedsmen have established an annual testing of new flowers
in what are called the "All-American Trials." New varieties entered
by seed growers are planted at a number of locations scattered over
the country. A committee of qualified seedsmen in each region
observes these plantings and rates each new production on its merits.
Awards are then given for the most outstanding introductions.
This plan has afforded an excellent stimulus to flower breeding and
has probably had much to do with the recent expansion of this work
by seed growers.
TECHNIQUE OF BREEDING
The first step in breeding work is the transfer of pollen from the
anthers to the stigma of a flower. Two types of pollination are
distinguished: self-pollination, when the pollen is produced by the
same flower as the seed or by another flower on the same plant; and
cross-pollination, when the pollen comes from another plant. Self-
pollination is easily accomplished in most cases by enclosing the plant
or its flowers in some sort of cloth cage or paper bag so as to protect
them from all pollen except their own (fig. 7). Some plants may
need a pollinating agent, even though they are fully self-fertile,
because the pollen of the flower is shed before its own stigma is recep-
tive, or because the stigma protrudes up above the anthers, or for
some other reason. Sometimes such plants merely need to be shaken
several times each day in order to scatter the pollen in the bag or
cloth cage. Sometimes the best pollination can be secured by the
aid of insect visitors, such as flies, bees, or some other species 2 intro-
duced into the cage.
Frequently, however, there is difficulty in getting certain crosses
to "take." Sometimes the pollen grain is unable to germinate on
the stigma; sometimes it germinates but fails to grow down the style
to the egg; sometimes it grows down the style, but the rate of growth
is too slow to effect fertilization. Some ingenious devices have been
used to overcome these difficulties. When the pollen grains refuse
to start growth, they may be germinated in a very weak sugar solu-
tion, which is then daubed on the stigma. If the difficulty is due to
slow rate of growth, the pollen grains may be placed on the stigma
of a young, unopened flower so that they have the advantage of an
early start on their journey. If the pollen tubes simply cannot grow
down the style tissue, however, there seems to be no remedy, though
the same pollen may function normally on the stigma of another
closely related plant.
Some investigators have thought that the retardation of growth
of pollen tubes was a result of some sort of inhibiting material present
either in the style or the ovary of the flower. A Japanese scientist,
1 See the article on Onion Improvement in this Yearbook for a description of this method.
FLO ff ERS
899
Yasuda (558), ,3 became interested in this problem and devised a unique
experiment with petunias. In these flowers there occur some self-
sterile races. Preliminary work indicated that sterility was due to a
slow rate of growth of the pollen tubes. The same pollen applied to
other races grew rapidly and effected fertilization. Yasuda conceived
the idea of grafting
styles from one race > .M
of petunias to another. |S <V
The reader who is fa- " £ ,
miliar with the parts of
an average petunia will
readily appreciate his
difficulties. This very
delicate operation was
performed with a fairly
high degree of success by
gluing the grafted style,
including its stigma, to
the new ovary with a
thin layer of gelatine.
It was then held in place
by being tied, with a
thread taken from a
spider's web, to a very
fine wire support fas-
tened rigidly beside the
flower. Since Yasuda
wished to determine the
source of the material
that inhibited the
growth of the pollen
tubes, he made recip-
rocal grafts.
After the grafts had
"taken", pollen was ap-
plied to each stigma.
On some stigmas the
plant's own pollen was
applied ; on others, pol-
len from another race.
In each instance un-
graf ted styles were used
as checks, some self-pollinated and some crossed. The rate of growth
of pollen tubes from the plant's own pollen was more rapid in its own
styles when they were grafted on ovaries of another race. Yasuda
thought this indicated that an inhibiting substance might originate
in the ovary of the flower. Unfortunately, though the rate of pollen-
tube growth was given, no statement was made as to whether seed
was actually set in ovaries with grafted styles. In this work Yasuda
was interested only in the possible presence of the inhibiting material
that caused a slow rate of pollen-tube growth.
3 Italic numbers in parentheses refer to Literature Cited. See notice, p. 977.
Figure 7. — Controlled pollinations of snapdragons.
Flowers are enclosed in a glassine bag, and each opera-
tion is recorded on attached tag. (From Plilgardia,
University of California.)
900
YEARBOOK, 1937
Figure 8.
(Legend on opposite page.)
FLOWERS 901
This same condition of re tardea growth rate of pollen tubes is also
known in other plants. It has been shown in tobacco and a few
others that a series of genes actually control pollen-tube growth, and
it is assumed that such genes cause the formation of these inhibiting
materials.
The unique method of Yasuda may lead to something valuable in
flower breeding. In some cases of cross-pollination wbere the pollen
will not grow in the maternal style it may be possible to secure
hybrids by grafting a style from the pollen parent to the seed parent.
This, of course, would not work if the inhibiting cause is a substance
in the maternal ovary.
Successful cross-pollination depends to a great extent on having a
thorough knowledge of the structure of the flower to be pollinated.
In some instances it may be so constructed that considerable skill in
manipulation is necessary to secure even a low percentage of successful
crosses.
When a cross-pollination is to be made it is essential that every pre-
caution be taken to safeguard the stigma from all other pollen. In
general this requires the removal of the anthers before pollen is shed.
In the case of many members of the composite family, such as mari-
golds, this is so difficult that another less certain but fairly efficient
method is sometimes used. It is based on the structure of the com-
posite floret, in which the style is surrounded by the anthers, which
form a closed circle about it. As the style grows it pushes up through
the column of anthers, collecting pollen as it goes. The rate of this
growth is so rapid in some composite flowers that the stigma emerges
from the anthers before the pollen has had time to germinate. If a fine
stream of water of moderate force is used promptly, the pollen grains
can frequently be washed from the stigma before they germinate.
The structure of some of the commoner flowers is shown in figures
8, 9, and 10. In each instance a longitudinal section is shown in order
to bring out clearly the floral parts most important in pollination —
the anther, the stigma, and the ovary.
Figure 8 shows some of the flowers in which controlled pollination
is most easily effected.
The morning-glory (fig. 8, A) is an easy type of flower to emasculate.
As shown in the drawing, the style is slightly longer than the stamens.
Such a stylo is said to be exserted beyond the anthers. When a cross-
pollination of morning-glories is to be performed, the anthers are
removed at any time before they shed their pollen.
The petunia flower shown in figure 8, C, is very similar to the morning-
glory. There are, however, other flower types in petunia that are more
complex. In some of the extreme double types the stamens are greatly
reduced or eliminated entirely. Such a flower can be used only as a ma-
ternal parent, and crosses are easily made since anthers are not present.
Figure 8. — Structure of (A) morning-glory, (B) nasturtium, (C) petunia, (D) gladiolus,
(E) phlox, (.F) carnation, (G) verbena, and (H) scabiosa to show arrangement of the
parts concerned in pollination. The anthers, stigma, and ovary are labeled a, s, and o,
and in all instances each flower has been split open and drawn to show the relative
position of these three parts. The technique for pollination of each is discussed in
the text.
902
YEARBOOK, 1937
Figure 9.
(Legend on opposite page.)
FLOWERS 903
In the nasturtium (fig. 8, B) the anthers form a tight cluster about
the pistil. They are large and may be easily removed before they shed
any pollen.
The gladiolus (fig. 8, D) has large anthers and a branching, plumclike
stigma. Emasculation is very easily accomplished.
Phlox and verbena (fig. 8, E and 6) are very similar in structure,
and emasculation is practically identical for both. As can be seen
from the illustration, the anthers are fastened to the inside of the tube
formed by the petals and may be removed with the corolla, to which
they are attached. This should be done just before the small bud
opens, shortly after color has appeared in the folded petals. A slight
pull at this time brings off the corolla tube with the anthers and leaves
the stigma, which may be pollinated when it is receptive.
The carnations or pinks (fig. 8, F) also have a wide range of flower
types. Only the single form is mentioned here. As can be seen from
the figure, removal of the anthers is comparatively simple.
The scabiosa (fig. 8, II) is very similar to a composite flower. Here the
so-called flower is actually a head of many small florets. In the figure
a normal floret and one split open are shown. The anthers protrude
so far beyond the stigma that their removal is easily accomplished.
The scarlet sage (fig. 9, A) has a rather unusual arrangement of its
anthers. As shown in the illustration, they are held out from the flower
wall by a bracelike arrangement. The stigma protrudes beyond them.
The larkspur (fig. 9, B) has a large number of anthers, which fit very
closely about the stigmas of the compound ovary. The anthers may
be removed with little injury to the flower, but caution must be
exercised to get them all.
Roses vary from the single to the double form. The one shown
(fig. 9, (J) is a double hybrid tea. In emasculating, it is always advis-
able to clip away as much of the petals as possible. This gives ready
access to the anthers, which can then be easily removed.
The sweet pea and the perennial pea are identical as far as emascu-
lation technique is concerned. The sweet pea flower is one of the
most difficult to emasculate without causing injury. The anthers,
as shown in the perennial pea (fig. 9, D) form a closed column around
the greater part of the ovary. They then branch out and closely sur-
round the stigma. The removal of this column of anthers frequently
injures the ovary, which is tender and brittle. It takes considerable
practice to become skillful in the operation.
The snapdragon (fig. 9, E) is very easy to emasculate. The anthers
do not shed pollen until the flower is fairly large. They may be
removed readily without injury to the flower.
In figure 10 several members of the composite family are shown.
While all have certain structures in common, there are also some
differences that probably warrant a few words of explanation. In this
large family of plants, the so-called "flower" is actually a group of
Figure 9. — Structure of (A) scarlet sage, (B) larkspur, (C) rose, (D) perennial pea, and
(E) snapdragon to show arrangement of the parts concerned in pollination. The
anthers, stigmas, and ovary are labeled a, s, and o, and in all instances each flower has
been split open and drawn to show the relative position of these three parts. The
technique for pollination of each is discussed in the text.
904
YEARBOOK, 1937
•/K ,
Figure 10.
(Legend on opposite page.)
FLOWERS 905
many small flowers called florets, massed closely together in what is
sometimes called a "head." These florets are of two distinct types.
Some produce both pollen and ovules and are termed perfect flowers ;
others lack anthers for pollen production but have pistils for ovule
production, and are called pistillate flowers. These small florets may
also be classified as to the form of the corolla. In one type the corolla
forms an inconspicuous tube surrounding anthers and style. These
are found in the center of the head and are called disk florets. In the
second type, called the ray floret, the corolla is modified into a con-
spicuous flat petallike structure, and extends far beyond other parts.
The proportion between the two types varies considerably. The
doubleness of any composite flower is determined by the number of
ray florets. In extremely double flowers in this family, all the florets
may be of the ray type.
The zinnia flower (fig. 10, A) occurs in at least four types. This
information, as yet unpublished, was kindly furnished by C. F. Poole,
of the Department. Ho is continuing his work on zinnias, which he
started while a member of the staff of the College of Agriculture of
the University of California.
The primitive or wild type is common in practically all races of
zinnias. It is called "medicine hat" by seedsmen, and is illustrated at
the top left of figure 10. The flower head has a single outer row of
ray flowers, all of which are pistillate. The disk flowers are arranged
in a somewhat pyramidal form and are all perfect. To the right of
the medicine-hat type are shown a single perfect flower and one in
which the corolla tube, which is the petal of the floret, has been split
to show the anthers and style. Directly below this is shown a flower
head of a second type, extremely double. Here all the florets are
pistillate (female) and no pollen is found in the entire head. A single
floret is shown below it in which the absence of anthers is conspicuous.
Between these extremes are two intermediate types. One, more like
the medicine hat, has several rows of pistillate florets and fewer per-
fect flowers. The second has a further reduction of perfect florets
and more closely resembles the very double, purely pistillate flower
head. Flower growers are interested chiefly in the more double types.
These can set seed only if pollinated by some other type. A plant
bearing only pistillate florets will certainly not set seed if it is grown
under a cage or otherwise isolated from sources of pollen. This is
probably the real explanation for some of the self-sterility in zinnias
reported by some seedsmen when single plants were grown under
cages. Sometimes more than one type of flower head is found on a
plant. This condition has not been investigated.
From the above description it will be seen that cross-pollination in
zinnias may be done without resorting to emasculation. If sterility
factors are not present it is only necessary to make sure of the source
of the pollen that reaches the stigmas of pistillate florets. In some
Figure 10. — Structure of (A) zinnia, (B) asler, (C) cosmos, (D) marigold, and (E)
dahlia to show arrangement of the parts concerned in pollination. The anthers, stigma,
and ovary arc labeled a, s, and o, and in all instances each flower has been split open
and drawn to show the relative position of these three parts. The technique for
.pollination of each is discussed in the text.
138904°— 37 58
906 YEARBOOK, 1937
cases this may require the cutting away of perfect disk flowers, but
in the purely pistillate double flowers no anthers are present and so no
preliminary work is necessary.
As far as could be determined there is no report of any cross-breeding
in the China-aster. It is likely th at cross-pollinations have been made
by amateurs and seedsmen, but no record of this has been available.
A careful study of aster flower types (fig. 10, B) similar to that of the
zinnia has apparently not been made. The aster flower head shown
in the figure has both pistillate ray florets and perfect disk florets, and
their proportion is a measure of the doublencss of the flower. If there
is no complication from sterility, it should bo fairly simple to control
pollination. Small, curved, sharp scissors could be used to cut out all
the perfect florets, and the remaining pistillate ones could then be
pollinated as desired.
There is also a wide range of flower types in cosmos. The one illus-
trated (fig. 10, (7) is a "single" type. All the florets are perfect, so that
cross-pollination would here entail emasculation or removal of the
anthers. Cross-pollination might also be done after using a stream of
water to wash off all pollen after the two-parted, feathery stigmas have
pushed their way through the anthers. If removal of the anthers is
necessary, an excellent tool can be made by hammering flat the head of a
pin, which is then bent and inserted in the end of a small wooden handle.
By careful manipulation the corolla tube with anthers attached can
be cut away. Unless considerable skill is attained, this operation
will have a high mortality rate among the flowers on which it is used.
The marigold flower shown in figure 10, D, is very similar to the aster.
There is, however, a wide range of flower types in marigold, as in nearly
all other composites. In this flower there arc several outer rows of
pistillate florets, and those in the center disk are all perfect. The two
types of florets are shown below the flower head with a perfect floret
split open at the lower left to show anthers and stigma. Cross-polli-
nation in this flower is essentially the same as in the aster.
In the dahlia (fig. 10, E) there is a range of flower types from the
ordinary single to the complete double. In the single type the flower
head is practically the same as the medicine-hat zinnia. In the outer
row the florets are pistillate; the disk flowers are perfect. From this
all gradations exist up to the fully double type, in which practically all
the florets are pistillate. Since these pistillate florets do not produce
pollen, few seeds are produced by the large double-flowered dahlias.
The flower shown here is an intermediate double type. To the left is
a perfect disk flower as it looks when removed and split open to show
style, stigma, and anthers. Self -sterility is the rule in garden dahlias.
This makes crossing very simple, since emasculation is not necessary.
There are several precautions to follow in emasculating all flowers.
The forceps or other tool used should be kept absolutely clean so that
no pollen is carried from plant to plant. This can be done by holding it
in alcohol for a minute or so before moving to the next flower. It is also
necessary to keep the emasculated flower protected from any chance pol-
len. This is readily done by covering it with a bag until after the con-
trolled cross-pollination h as been made and fertilization has taken place.
The time to apply pollen is also sometimes a problem. In general,
it should be done just as soon as the sticky fluid that develops on the
FLOWERS 907
stigma makes it appear moist and shiny. This fluid holds the pollen
grains and is nutritive material favorable to their germination.
Methods of Producing Superior Types of Flowers
The earliest and most commonly used method for breeding flowers is
known as mass selection. It consists simply in saving for seed only
the best plants of a variety. - The procedure does not take into account
the fact that better plants may be the result of either a better environ-
ment or a superior germ plasm. Since the seed from all the selected
plants are mixed together before planting, it is difficult to evaluate any
progress made. The method also does not differentiate between plants
that are highly cross-pollinated and those normally self-pollinated; it
is concerned only with the seed-bearing (maternal) parent. Most of
our present flower varieties probably were developed in this way.
Mass Selection and Line Breeding
Mass selection does result in a gradual improvement even if some of
the selected plants transmit poor germ plasm to the next generation,
since the good ones have a better chance to be selected and in time
predominate, gradually building up the variety. In this way desirable
results are often secured, but frequently many years are required be-
fore the effects are noticeable. It is not true, however, even though
commonly believed, that the selection process in itself is responsible
for the gradual changing or improvement of a flower. There is little
reason, in the light of our present information on plant breeding, to
continue using this method. But even today it is the general practice
among many flower breeders.
Following mass selection came so-called line-breeding. Here the
breeder selected single plants and grew the seedlings from each selec-
tion separately. In this way the descendants of au individual plant
could be studied, and the method was soon recognized as a considerable
improvement over the earlier practice. It was possible to determine
more readily whether an observed variation was hereditary (in the
germ plasm) or simply an environmental modification. It also dis-
closed the status of a given characteristic in the heredity of a plant.
If all the seedlings possessed the characteristic, it might be assumed that
the plant was "pure" or homozygous for that characteristic and that it
would be passed on to all the descendants; if some seedlings had it and
some did not, the plant was heterozygous or mixed iu its inheritance.
Unfortunately much of the single-plant-selection work of both ama-
teur and professional flower breeders is done with open-pollinated
plants — that is, no provision is made to protect from cross-pollination
with other nearby plants. Of course, if a flower is normally self-
pollinated, it may not be necessary to have this protection, but there
are not many flowering plants that are entirely self-pollinated. The
outstanding one supposed to be self-pollinated is the sweet pea.
Here the stigma, completely surrounded by a group of anthers, is
enclosed in that portion of the flower called the keel (fig. 9, D). When
the flower matures the pollen is shed and falls on the stigma, which
normally does not protrude from the petals forming the keel. In this
manner the flower is supposedly protected from all pollen except its
own.
908 YEARBOOK, 1937
Yet conditions in sweet-pea seed fields make this doubtful. If the
sweet pea is entirely self-pollinated, it should be a simple matter to
keep varieties pure (homozygous)j since they could only acquire new
genes by way of mutations. While the mutation rate in sweet peas
has not been studied, the very large number of offtype plants (rogues)
in sweet-pea seed fields certainly cannot be explained on this basis.
In some instances these rogues are simply the result of accidental
seed mixing, but this is not likely to occur in the case of the more
careful growers, who keep their stock seeds separate. Very fre-
quently, also, sweet-pea breeders encounter considerable difficulty in
making a strain pure. An examination of several such cases showed
that many of the flowers were not fully protected from cross-pollina-
tion, as had been assumed. The keel was not fully developed and
was too short for the pistil and anthers. As a result the stigma very
frequently protruded, even beyond the anthers, so that cross-pollina-
tion could easily have occurred.
There are some flowers in which the single-plant-selection method,
depending on self-pollination, cannot be used. This may be due to
self-sterility, as in some lily species, especially most forms of Lilium
longiflorum Thunb., and in some iris, petunia, and Nicotiana species.
Sometimes reasons other than self-sterility are responsible for failure
of flowers to set seed when single plants are isolated. The pollen
may be discharged before the stigma is receptive, or the reverse con-
dition may occur. The structure of the flower may be such that self-
pollination is impossible without the aid of some agency such as in-
sects. Sometimes, as in species of Lychnis, the plants are either
male (staminate) or female (pistillate). Such types obviously cannot
be self-pollinated.
Single-plant selection or line breeding has many advantages over
mass selections. When accompanied with self-pollination it quickly
gives strains very uniform for habit of growth and other characters.
All undesirable qualities are disclosed rapidly and may be eliminated
within a comparatively few generations. Unfortunately, continued
self-pollination frequently results in a loss of vigor. As a rule this
weakened condition may be corrected by making cross-pollinations
between inbred strains. This situation has received considerable
attention from corn breeders and is discussed at some length in the
1936 Yearbook of Agriculture.
Hybridization
A third method of flower breeding is the making of crosses between
plants to secure new individuals that combine desirable qualities
from each parent. While it is true that many of the early workers
did cross-pollinate flowers, few realized the necessity of carrying their
work beyond the first hybrid generation, called the F,. In other
words, if none of the hybrids was desirable, all were discarded.
The rediscovery of Mendel's work in 1900 demonstrated at once
the importance of continuing into subsequent generations. Mendel
showed that when two plants are crossed, each contributes to the
heredity of the resulting hybrid. While ordinarily these contribu-
tions are exactly equal in quantity, they may vary qualitatively.
When the two bits of heredity-carrying protoplasm, male and female,
FLOWERS 909
are united in one individual, the hybrid, new combinations of char-
acters become possible in the descendants of this hybrid. These new
combinations may not be seen in the hybrid, but they will appear in
some plants of the population descending from it.
Unfortunately, Mendel's basic laws are still unknown to many
flower breeders. Each year many thousands of hybrid seedlings are.
undoubtedly grown and discarded as being inferior. If many of these
had been carried into the next generation, it is likely that some worth-
while plants would have appeared. It is this second generation,
commonly called the F2, in which recombinations of parental char-
acters are found.
In some instances the hybrid between two flowers is self-sterile.
This commonly occurs when the two parents are from different species.
Although the hybrid sets no seed with its own pollen, some seed may
often be secured by crossing it with one or both of its parents. This
is commonly called backcrossing. A backcross may be made in both
directions; that is, the hybrid may be crossed to the maternal or the
paternal parent. Sometimes a backcross will produce fertile seed
in only one way, and as a rule it is more often successful when the
hybrid is used as the maternal parent.
The method of improvement by hybridization will undoubtedly
play an increasing role in flower breeding. It is the only way by which
new combinations of desirable germ plasm can be effected. Very
frequently a variety may be desirable in many ways, yet have some
one characteristic that causes it to be unpopular. In many cases this
character can be replaced by a desirable one from some other variety.
A cross between them will provide an opportunity to combine the
desirable traits of both parents in the F2 or later generations. Some
of the characters of one parent may be recessives, in which case they
will not be apparent in the hybrid, but they will appear in some
members of the next generation. Here, too, will be found the recom-
binations, that is, the new plants produced by combinations of char-
acters from each parent. But since the genes, or carriers of heredity,
are in the chromosomes, and all the genes in the same chromosome
tend to be inherited together (this is the phenomenon known as
linkage), we may find undesirable qualities associated with the ones
we want. When this occurs it is necessary to grow populations
large enough to get a reassortment of the genes or characters, which is
brought about by what is called crossing-over, or the occasional
exchange of material between chromosomes when the pollen grains
and egg cells are being formed.
The backcross procedure mentioned above is probably one of the
most valuable methods the flower breeder can use, and it should be
more widely employed by amateurs and professionals. When two
plants are crossed, usually the breeder has in mind some ideal type
that he hopes to fashion by combining many desirable characters
from one parent with fewer characters of the other. When this is
true, it is best as a rule to backcross the hybrid to the more desirable
parent. The resulting offspring may be again backcrossed one or
more times and then self -pollinated. In a few generations the chances
are that the desired inheritance of the best parent will be piled up
and by selection the desirable characters of the other parent can be
910 YEARBOOK, 1937
retained so that plants closely approximating the ideal will be secured.
The chief merit of this method is in recovering the quantitative
characters of one parent from comparatively small populations in a
relatively short time. , ,
J Mutations
. In addition to the breeding methods already discussed, many vari-
eties of flowers originate as mutations or sports. Mutations may
arise in the pollen grains or in the egg cells, or they may occur in
cells of the stems, leaves, flowers, or other portions of the plant.
Many of our varieties of roses, carnations, and chrysanthemums have
appeared in this way. Sometimes a side branch bears a flower dif-
fering in color or size from the remainder of the parent plant. When
the plant can be propagated vegetatively, it is usually a simple mat-
ter to introduce the changed form or mutant as a new variety. For
some as yet unknown reason, certain varieties of some flowers are
especially noted for the number of bud sports they have produced.
This is particularly true of the Ophelia rose. Many of the present-
day varieties of greenhouse carnations are also mutations of this sort.
When a mutation occurs in a sex cell it does not appear until the
next generation. If it is a recessive and the parent plant normally
is cross-pollinated it may not show up for several generations. It is
entirely probable that some of the new characters that appear in a
variety of flowers grown from seed arise as sex-cell mutations. The
vast majority of the so-called "breaks", however, are not mutations
but simply recombinations of already existing characters following
cross-fertilization (fig. 11).
Since the chromosomes are the carriers of the hereditaiy units, any
changes in them should have an effect on the plant. Such a change
may effect a rearrangement of the genes in a single chromosome or
even the loss of some of them. Sometimes a whole chromosome is
lost or an extra one added, or each chromosome is reduplicated so
that the entire number is doubled. Occasionally one may be broken and
the fragment retained or lost. The plant that results from any of these
changes is likely to be different from one with normal chromosomes.
The doubling of the chromosome number may occur in several ways.
The sex cells sometimes form with all the chromosomes present rather
than half the number, which is normal for sex cells. In other instances
an ordinary cell in a stem or root may double up its chromosome num-
ber, and then when this doubled cell divides all its descendants will
have the doubled number.
A well-known example of the doubling of the chromosome number
in stem cells is the case of Primula kewensis W. Wats. (Kew primrose),
as reported by Digby (111) in 1912, and by Newton and Pellew (890)
in 1929 (fig. 12). It is a desirable primula, now quite commonly
grown by many florists. It originated in this manner: A cross was
made between the species P. floribunda Wall, (buttercup primrose)
and P. verticillata Forsk. (Arabian primrose). The hybrid was com-
pletely sterile for many years, when there suddenly appeared on one
plant a branch that bore large fertile flowers. The chromosome num-
ber of both floribunda and verticillata is 18, and that of the large-flow-
ered branch was 36. Undoubtedly this branch arose from a cell that
had doubled its chromosome number.
FLOWERS
911
Another interesting instance of the origin of a large-flowered plant
as a result of chromosome doubling was reported in Campanula
yersicijolia L. (peachleaf bellflower) by Gairdner in 1926. The
normal species has 16
chromosomes, and
from it came a seed-
ling with 32 chromo-
somes. The doubling
of the chromosome
number resulted in a
considerable increase
in size, and the new
variety was named
Telham Beauty.
Quite recently,
Randolph (423), of the
Bureau of Plant In-
dustry, in cooperation
with Cornell Univer-
sity, has developed a
method by which
chromosome numbers
of corn may be dou-
bled. While no report
has as yet appeared
concerning its use for
doubling chromosome
numbers of flowers, it
seems likely to play
an important role in
future flower breeding.
The results are secur-
ed by the application
of heat to the flower
just after fertilization
has taken place. The
time between applica-
tion of pollen to a
stigma and the actual
union of the two sex
cells is very variable.
It may require only a
few hours or it may
take several days.
The new cell formed
by the union of the
two is the first cell of
the young embryo.
This one-celled em-
bryo usually does not
divide for some time,
and it is during this
Figure II. A horticultural form of foxglove iii which t lie
top flowers are united to form a round, hollyhocklike
flower. This photograph was sent to the senior author
as representing a possible new mutation supposedly aris-
ing spontaneously in a home flower garden. It is a form
that is not widely distributed but has been known for a
long time. It is recessive, so that when crossed with
"normal" all the hybrids are normal and the next gen-
eration is composed of 3 normal to 1 abnormal.
912
YEARBOOK, 1937
period just at or before division that heat is applied. Since the temper-
ature necessary is very likely to be different with different plants, it can
be seen that a considerable amount of preliminary investigation will
be needed before this method can be used with certainty.
There are on record several cases of spontaneous doubling of the
chromosomes in the one-celled embryo. The one of interest here,
because the parents, commonly called flowering tobaccos, are fre-
quently found in flower
gardens, is that of Nico-
tiana digluta Clausen
and Goodspeed. Clau-
sen and Goodspeed (76)
reported a plant with
72 chromosomes com-
ing from a cross between
N. glutinosa L. with 24
chromosomes and N.
tabacum var. purpurea
with 48 chromosomes.
All the hybrids should
have had 36 chromo-
somes, but this one
plant had 72. They
believed that this par-
ticular Fj plant had
doubled its chromo-
some number shortly
after fertilization.
There is also evidence
of a similar occurrence
in tomatoes. In gen-
eral the doubling of the
chromosome number is
usually^ accompanied
by an increase in the
size of the plant and
flower.
Chromosomes may
also be modified in
structure. The modi-
fication may result
from the breaking of
a chromosome into
several parts, or from a slight change in one of the genes that it
carries. There are many recorded instances of such changes
occurring in nature. Frequently they cause freakish and abnormal
plants, but they arc also responsible for many worth-while new
variations. Until recently these changes were purely chance occur-
rences over which the breeder had no control. Recently, however
certain external agents such as X-rays, radium, ultraviolet light'
heat, and some chemicals have been shown to be effective in produc-
ing them.
Figure 12. — Diagrammatic drawing showing ihe effect
of the doubling of the chromosome number in a species
hybrid. The plant is a cross between (a) the Arabian
primrose {Primula verticillata) and (6) the buttercup
primrose (P.floribunda). It has 18 chromosomes, like
each of its parents (the chromosomes are represented
near one of the upper flowers). Suddenly it produced
the lower branch with larger flowers, and this was found
to have 36 chromosomes (represented on one of the
petals). Whereas the hybrid itself was sterile and set
no seed, the new branch with 36 chromosomes was fertile
and set seed. This fertile side branch was the progenitor
(c) of the well-known Kew primrose (P. hewensis).
FLOWERS
913
Artificial Methods of Changing Germ Plasm
The use of X-rays, radium, and ultraviolet light for the production of
new flower types will probably not become general. Considerable dan-
ger is involved, and the work should be done only by thoroughly trained
technicians. The actual manner in which these agencies cause the chro-
mosome to change is not known, ^ ^^___^_^_^___^__ _
but the very short rays seem to
incite rearrangement of genes and
even chromosome breaking.
Some of the earlier work show-
ing the effect of X-rays and ra-
dium on flowers was done by T.
H. Goodspeed (fig. 13) and his
associates at the University of
California. The plants were sev-
eral species of ornamental tobac-
cos. Both seeds and sex cells
were exposed to the action of ra-
dium and X-rays. In the case
of ungerminated seeds there fol-
lowed a very noticeable retard-
ing of germination, but at matu-
rity no general effect of X-radia-
tion of the seeds could be seen.
If, however, the seed was germi-
nating or if tiny seedlings wore
X-rayed, many changes in growth
and form were noticed.
In another series of experiments
by Goodspeed and Avery {14-5),
sex cells were exposed to X-rays.
This was done by X-raying buds
in which the egg mother cells were just beginning to go through the
series of divisions that give rise to the egg cells or female gametes.
After this treatment these buds were pollinated with pollen from
untreated flowers. Now if a change occurred in an egg cell and this
egg cell was pollinated by normal pollen, the new condition would
show up at once if it was a dominant. If the new character was
recessive, however, it would not appear until the next generation.
Following this treatment many plants were secured that differed
markedly from their sister untreated plants. One of these variant
plants was selected for further study and was self-pollinated. After
six generations, that is, six cycles "from seed to seed", seven pure-
breeding new types and seven not yet fixed have been secured. Some
of these new types differ so markedly from their un-X-rayed sister
plant that they probably are entirely new varieties, and even in a few
instances new species. They differ from one another and from the
untreated plant in habit of growth, in form of leaf, flower, and capsule,
and even in the color of leaf and flower.
This series of experiments is remarkable in several respects. It is
the first to demonstrate the possibility of actually securing fertile new
Figure 13. — T. H. Goodspeed, professor of
lmtaiiv. and director. Botanical Garden,
University of California, Berkeley. One of
the pioneers in the use of X-rays and radium
to induce mutation in plants.
914 YEARBOOK, 1937
types of flowers by X-raying sex cells. All 14 types came from a
single X-rayed egg cell, which was pollinated by an untreated pollen
grain.
Recently there has appeared another report of effects of X-raying a
flowering plant. In the laboratory of the General Electric Co. at
Schenectady, N. Y., Moore {874) exposed Regal lily bulbs to X-rays.
Among those so treated, two upon blooming showed an unusual be-
havior of the anthers. The flowers differed only slightly from the
normal Regal, but the anthers did not open and shed their pollen.
Since the pollen is considered unsightly when scattered on the petals,
this nonshedding habit is considered by the originator as valuable.
These plants are easily propagated by divisions of the old bulb so
that they can be multiplied without recourse to seed and also with the
certainty they will all be identical, unless there is a reversion to the
normal.
Another series of interesting experiments with X-rays was con-
ducted by Morgan (877), who exposed seeds, flower buds, and corms
of freesias to various dosages. Very little effect was noticed on seed
and flowers except when exposures were strong and for rather long
periods. The corms, however, showed decided effects from the rays.
The untreated corms produced single plants, while as many as five
"shoots" were produced by a single X-rayed one. The treated corms
also started to germinate immediately after planting, made more
rapid progress, and showed curling and twisting of leaves and steins;
and the flowers were split and deformed. In general, the effect of
X-ray treatment in low dosage seemed to be an acceleration in the
rate of growth and the stimulation into growth of structures that
otherwise would have remained latent. With increase in intensity of
the dosage, the acceleration was lost and the rate of growth was even
retarded. The heaviest dosages killed the corms.
In another similar series of experiments, tulip bulbs were exposed
to X-rays by Van Heijningen and his associates (197) at the Wage-
ningen station in the Netherlands. In many instances the results
parallel those with the freesia corms. After moderately strong expo-
sures, the number of small increase tulip bulbs was slightly more than
in untreated bulbs. The flowers produced by the treated bulbs in
some cases had irregular incisions on the petals, quite similar to those
in the so-called Parrot varieties.
Not much in the way of practical results has been accomplished
as yet by using artificial physical methods to induce changes in the
germ plasm. This is not surprising, however, when it is remembered
that although earlier sporadic attempts had been made, less than 10
years have passed since the present type of research was started.
Much of the recent and current work of tins type with flowers and
other plants is still in the experimental stage. Enough has been done
to indicate that plants, and even parts of the same plant, differ in
response to the same dosages of rays. This means that much pre-
liminary work is necessary merely to discover what dosages^ to use.
There has also been too great a tendency for some to rush into the
work while lacking a proper background in genetics and plant breed-
ing. Instances are known in which seeds or pollen have been X-rayed,
and when nothing unusual appeared in the resulting plants the entire
FLOWERS 915
lot was discarded. If any recessive changes in the germ plasm were
effected, they might not appear until later generations. In this con-
nection it is recalled that Goodspeed continued his work into many
succeeding generations and located numerous definite new types. In
much of the work also, the number of treated individuals is very small.
If the frequency rate of valuable changes is but 2 or 3 in 1,000, there
will be little chance of securing them when only 10 to 20 seeds or
plants are treated.
WHAT THE STUDY OF CELLS CONTRIBUTES
TO FLOWER BREEDING
The trained breeder likes to know the number of chromosomes in the
plant with which he is working. For one thing, it determines the
number of individual plants he will have to grow to get a desired
recombination of the characters in which he is interested. Suppose,
to take a purely imaginary case, that a certain plant has oblong red
petals. The breeder wants to get a hybrid with the red color, but
does not want the oblong shape. Now if this plant has four chro-
mosomes in its sex cells, the chances are one in four that these two
characters are linked — that is, they are in the same chromosome and
will usually be passed on together in inheritance. But if there are
eight chromosomes, the chances are only one in eight that they will
be linked. In the latter case, he has twice as great a chance of getting
one character without the other. The smaller the number of chro-
mosomes, the greater the chance of linkage among any two or more
characters and the larger the number of individuals that will have to
be raised in an attempt to break up the linkage by crossing-over.
Another point of interest to the breeder is the important part that
chromosome numbers appear to play in the probability of securing
fertile crosses between two species. When both have the same
number, the chances for success are much greater than when they
differ. There are, however, many instances of hybrids between
species with different numbers of chromosomes. As a rule such
crosses are more likely to be successful when the one with the greater
number of chromosomes is used as the maternal parent. There are,
however, a few instances where crosses have been successful even
when the species with fewer chromosomes was the maternal parent.
In addition to the question of linkage, the chromosome number
may throw light on other questions. For instance, the lilies com-
monly have 12 chromosomes in their sex cells, which means that they
have twice 12 or 24 in their body cells (12 pairs). Now for years the
so-called Tiger lily (Lilium tigrinum Ker) was noted for its persistent
self-sterility. Recently it has been shown to have 36 chromosomes
in its body cells instead of 24 — 3 of each kind instead of 2 of each
kind.4 This is an abnormal condition, but it occurs fairly commonly
in plants, and it often accompanies or causes sterility. There are also
plants with four times the basic or sex-cell number of chromosomes,
or five times, or six times, and even some plants that retain the basic
or single number in the body cells instead of doubling this number,
which is the normal method. In some species of plants, different
4 A fertile tigrinum has been reported rather recently. According to Stout it varies somewhat from the
older common form and apparently has 24 chromosomes rather than 36. It is therefore a diploid.
916
A
•
B
J*
*tt
^
«/
/-
6*
>
»•• -.
"ifc^f (J
^5-
^
*
x. ' ••/
^
Figure 14 (legend on opposite page)
S
FLOWERS 917
varieties run a whole series of these numbers. Thus in the lilies there
might be one variety with 12 chromosomes in the body cells (haploids) ;
another with 24 chromosomes (diploids) as shown in figure 14; another
with 36 (triploids) ; another with 48 (tetraploids) ; another with 60
(pentaploids) ; another with 72 (hexaploids). Hereafter, these names
will be used to indicate the number of times the basic number is
multiplied in the body cells of the plant.
Variations in Chromosome Numbers
The question now arises as to how the knowledge that the Tiger
lily is a triploid can possibly aid flower breeding. To answer that,
it is necessary to give some preliminary discussion. First, it will be
remembered that normally the sex cells of a plant always contain half
the number of chromosomes in the body cells. This reduction in the
number of chromosomes is one of the things that happens when a
cell gets ready for reproduction. Now there are many known triploids
in plants, and without exception they are all highly self-sterile, but
some will set seed when pollinated by a diploid. It is probable that
these triploids arise in two ways.
(1) A tetraploid type may be pollinated by a diploid. For instance,
in the China-aster the basic or haploid chromosome number is 9, so
that a diploid would have 18 chromosomes and a tetraploid 36 in its
body cells. When the reproductive cells are formed, these numbers
are cut in half; the sex cell of the diploid has 9 chromosomes and that
of the tetraploid 18. Now the two sex cells join. Nine chromosomes
are added to 18 chromosomes, and the result is 27 chromosomes, or
a triploid, since 27 is three times the basic number.
(2) The male or the female nucleus of a normal diploid cell may
fail to reduce its chromosome number in preparing for reproduction.
In this instance it would keep 18 chromosomes instead of reducing
the number to 9. When it united with a normal sex cell having 9
chromosomes the total would be 18 plus 9, or 27— a triploid.
Figure 14. — Chromosomes and formation of pollen grains in the Easter lily as seen
under the microscope (X 350). A, The cell that will divide twice to form four pollen
grains. The chromosomes are all long fine threads and form a tangled knot. B, After
the first division is well started; the knot has unraveled and the chromosomes are
pairing. Since the lily has 24 chromosomes, there should be 12 pairs. C, The division
has progressed to where 12 pairs of chromosomes can be seen very clearly. D, A little
later stage of division, in which the chromosomes have become shorter and thicker.
The 12 pairs are all clear with the exception of no. 5, which lies under no. 6. E, A side
view of the 12 pairs just as they are about to separate. F, Here 12 chromosomes have
moved to each of two sides of the cell and the first division is almost completed. G, The
12 chromosomes in each group are now organizing new cells and getting ready to divide
again. //, There are now 12 chromosomes in each dark -stained nucleus, and each
nucleus will again divide to form 4, which finally become pollen grains, each with 12
chromosomes. /, Occasionally in the Easter lily something happens that causes the
chromosomes to break into many small pieces. Such results can be accomplished by
use of X-ray3, radium, and possibly heat treatment just before the cells start to divide.
/, In this cell 11 of the 12 chromosome pairs behaved normally, but two chromosomes
probably did not pair. They are the ones at top and bottom. K, A giant (tetraploid)
cell with 48 chromosomes instead of 24. Such cells are not known to have given rise
to any tetraploid lily plant.
918 YEARBOOK, 193 7
Tetraploid lilies are not known to occur, and it is therefore assumed
that the triploid form must have arisen in the latter fashion — -though
there may have been a tetraploid parent that has not been discovered
or that has become extinct.
If a triploid is not valuable in itself, there is usually little reason
for using it in a breeding program. As a rule, when it is crossed with
a diploid, the resulting hybrids are inferior, usually being dwarf, self-
sterile forms. If their chromosomes are examined they are found to
vary in number from plant to plant. Thus a few successful crosses
between the Tiger lily and other lily species have so far given only
small deformed seedlings. It has already been noted that the Tiger
lily has 36 chromosomes, the other species 24. While no evidence is
available as to the chromosome numbers in the hybrids, it is very
probable that some had 24, some 25, 26, 27, etc.
As more and more is accomplished in chromosome studies of flowers,
it is likely that we shall find other instances similar to the Tiger lily.
If a valuable triploid flowering plant appears and can be propagated
by cuttings, it is not essential that it be fertile and bear seed. For
instance, a valuable triploid carnation, chrysanthemum, rose, nar-
cissus, or geranium could easily be increased by division. With suit-
able developments in technique it might be possible to create other
triploid forms as fine as the Tiger lily.
Other Chromosome Peculiarities
Sometimes a variety persists in producing year after year a number
of peculiar variant forms. Even though it is carefully self-pollinated
the variant forms may reappear with great regularity. Such a plant
cannot be made to breed true, and sometimes the situation is the
result of the structure and behavior of its chromosomes. Keeping in
mind that the chromosomes carry the hereditary genes it is not strange
that these peculiarities of inheritance can be traced to abnormalities
in chromosomes.6 Such plants may show a peculiar behavior of their
chromosomes when sex cells are formed, as has been conclusively
demonstrated by cytologists working with the evening-primrose.
One of these evening-primroses, known as Lamarck's, produces
several variant forms year after year. At first plant breeders thought
these were distinct changes in genes in the chromosomes. They were
called mutants and the change in the gene was thought to have
happened when the sex cells were formed or before. Careful cyto-
logical study of chromosomes in the sex cells demonstrated that the
evening-primrose chromosomes act very irregularly while pollen grains
and egg cells are being formed. These irregularities result in some
few sex cells receiving an unusual combination of chromosomes. Since
chromosomes are the carriers of hereditary characteristics, such
peculiar sex cells naturally give rise to unusual and unexpected seed-
lings. Unless the sex cells had been examined under the microscope,
we would have continued believing that the evening-primrose pro-
duced a very large number of mutations. This might have led us
into other errors by encouraging the idea that mutations are relatively
common. In fact this belief does exist among many amateur and
s This statement has some exceptions, chiefly a few instances of cytoplasmic inheritance, dependent on
the cell material outside the nucleus.
FLOWERS 919
professional flower breeders. It is expressed in the claim of the sudden
appearance of what are commonly called "breaks", which follow the
crossing of two varieties. Thus we often see it stated in a popular
article that some new flower originated as a break from the hybrid
made by crossing two older varieties. It is unquestionable that muta-
tions do occur now and then, but they are comparatively rare. The
chances are preponderantly in favor of the breaks actually being
recombinations of characters that already existed in the two parents.
A situation that appeared to be somewhat similar to the evening-
primrose problem was called to the attention of the senior author of
this paper several years ago in California. The late J. H. Franklin, of
the Waller-Franklin Seed Co., told of a peculiar breeding behavior in
annual larkspur. He had been working for years with a pink-flowered
form called Exquisite Pink. The shade of color and the habit of the
plant were very desirable, and it was popular with florists. Unfortu-
nately he had not been able to get a pure-breeding strain. Year after
year his best selections produced the same variant forms. These
undesirable types included a white-flowered form, a rose, a blue, a rose
with blue flecks on the petals, a white with blue flecks, and a purplish
blue. He sent some seed to the California Agricultural Experiment
Station at Davis, where it was grown, and the plants were studied.
For 2 years, Exquisite Pink plants were self-pollinated and each time
they produced the same variant types. The next year microscopic
slides were made of the developing pollen grains, and some of the same
general types of irregularities wore found that occur in the evening-
primrose. Apparently some structural peculiarities in the chromo-
somes were causing the difficulties. This meant that the Exquisite
Pink larkspur could never breed true. When this was explained to
Dr. Franklin, the strain was discarded. New selections were started
with other pink-flowered forms, and at present there are several good
pink larkspurs available.
One of the most popular flowers for both breeding and cytological
research is the stock, Matthiola incana (L.) R. Br. This plant is unique
in that it has two distinctive types, the single- and double-flowered
forms, the latter containing no anthers or pistils and making no seed
whatever. Reproduction, then, is from seed produced by the single
flowered plants. The growers of stocks, both florists and amateurs,
are interested almost exclusively in the double forms. For some time
plant geneticists have known that there are three types of single plants.
One when self-pollinated produces no doubles, the second produces
about 25 percent of doubles, and the third from 54 to 56 percent.
Obviously the third type is the one to use for seed. It is called ever-
sporting because of the high percentage of doubles it produces.
The problem of explaining the peculiar behavior of the ever-sporting
stock attracted many workers. One quite logical explanation assumes
some condition that kills half the pollen grains and approximately 6 to
8 percent of the egg cells. This might be caused by what is called a
lethal gene located in the same chromosome as the gene for singleness.
The lethal gene would have to be recessive since if it was dominant all
plants with this gene would die. Being recessive a plant can carry the
gene and its normal allelomorph and be able to live. Let us use the
symbol a for the lethal gene and the symbol A to represent the normal
920 YEARBOOK, 1937
allelomorphic gone that is dominant to a; then all plants of the aa type
would die, but Aa plants would live.
Now singleness in these stocks is dominant to doubleness. Single-
flowered plants may be pure (homozygous) for singleness, or they may
be hybrid (heterozygous) for this character. A pure (homozygous)
single gives only singles when it. is self-pollinated. A heterozygous
plant gives 3 singles to 1 double. According to the above theory, the
third type, the ever-sporting race, should be hybrid (heterozygous) for
singleness and for the linked lethal, which would result in 54 to 56
percent of doubles instead of only 25 percent.
In 1931 Philp and Huskins (408) published a cytological study on
ever-sporting stocks that apparently explained "the situation.6 In
order to understand their work it is necessary to recall that only one of
each pair of chromosomes occurs in a sex cell. The pair of chromo-
somes of which one member carries the gene for doubleness and the.
other member the gene for singleness, therefore, never get into the same
sex cell.7 Philp and Huskins are able to show that ever-sporting single
plants had one pair of chromosomes that differed from one another in
appearance, one lacking a small knob on its end . This is very signifi-
cant when it is remembered that the two chromosomes of a pair
normally have an identical shape. From their work, they stated that
the pollen grains getting the chromosome lacking the knob did not
function. In other words, the absence of the small knob acted as a
lethal to the pollen grains in which it occurred.
If only the "double" pollen grains can function, while both "double"
and "single" eggs are good, it is easy to see how such plants produce
about half doubles and half singles. The fact that the ratio is not
exactly 50-50 is explained by assuming that a few egg cells getting the
chromosome lacking the knob do not function. This explanation was
verified to some extent by a study of pollen germinations from pure
and ever-sporting singles, which showed that germination of ever-
sporting pollen was only about half that of pollen from pure singles.
Evidently about half the pollen grains of an ever-sporting single were
being killed in some manner.
The entire situation is much clearer if figure 15 is studied. At the
top are shown the seven pairs of chromosomes of a single-flowered
ever-sporting stock plant. The members of each chromosome pair
look exactly alike with the exception of the first. One lacks the little
knob on one end, which cytologists call a satellite. A large 8 is
printed before the one that lacks the satellite. This is to represent
the gene for singleness, which it carries. Its mate (homologue) has a
small s to represent the gene for doubleness, which is recessive. The
chromosomes of the eggs and pollen grains produced by this single-
flowered plant are also shown. They are of two types, I and II, and
half the eggs are of one and half of the other type. This is also true of
the pollen grains. According to Philp and Huskins, however, only
those pollen grains with the satellited chromosome function, and all
the eggs live except about 6 to 8 percent of those lacking a satellite.
Since only one type of pollen grain lives, there will result just two
types of plants. They are shown at the lower part of the diagram.
« This work has recently been questioned by Vestergaard and may need further investigation.
' This actually happens occasionally, as discussed earlier, when a diploid sex cell is formed.
FLOWERS
921
One will be single, since it receives the knobless chromosome with the
single gene, and the other will be double, receiving two double-
flowering (s) genes and two satellited chromosomes. Since there are
not quite so many eggs carrying the large S for single flowers, the result
is about 54 to 56 percent of doubles and 44 to 46 percent of singles.
Philp and Huskins report that all doubles examined by them had two
■fl a a » «
ii *•»
2 3 4 5
POLLEN GRAINS
ALL DIE
ALL LIVE
ttj|\l«»ff" sf\W\\«M'r"
DOUBLE-FLOWERED SINGLE-FLOWERED
Figure 15. — The chromosome situation in ever-sporting, double-flowering stocks.
satellites, while all singles had but one. This refers, of course, only
to the ever-sporting races.
Another cytologist, Frost (185), working with stocks, has also dem-
onstrated the value of cytology to flower breeding. He has shown
that the proportion of double-flowered plants may be increased very
materially. Among the various types of stocks he had in his experi-
mental plot was an ever-sporting form known as Snowflake. In tins
variety he found a peculiar single-flowered plant that had very narrow
slender leaves. When this plant was self-pollinated it gave about 47
percent of singles and 53 percent of doubles. About 37 in every
100 plants had the narrow slender leaves of the parent,. Also, these
plants were very weak in growth and had no_ decorative value. The
remaining normal plants descended from this narrow-leaved parent
were found to be about 90 percent of doubles. Since the slender
leaves are conspicuous even in the seedling stage, the plants having
them may be discarded at that stage, and among the remaining
plants there will be only about 10 percent of singles. In order to
continue this situation, however, it is necessary that seed be saved
only from the slender-leaved types.
The explanation for this interesting condition was worked out by
making a cytological study of the chromosomes of the slender plants.
In addition to the 14 chromosomes expected, these plants showed a
small chromosome piece, which cytologists commonly call a fragment.
These plants, then, had 14 + 1 chromosomes. Evidently this frag-
138004°— 37-
-50 ++
922
YEARBOOK, 1937
ment was the part that carried the gene for singleness or doubleness.
Since only slender-type plants had this fragment, it was concluded that
the slender leaves were also caused by its presence. Since a gene for
singleness was also in the fragment, these two characters, singleness and
slender leaf, behaved as linked genes do ; that is, they tended to remain
together from generation to generation. Thus if the slender plants
are discarded in the seedling stage, it means the removal of most of
the singles. This very unique scheme is not in practice as yet, prob-
ably because it is not understood by the average flower breeder.
Since the chromosome number of a plant does have considerable
importance in breeding work, a list of chromosome numbers of some
of the most common flowers is given in table 1 .
Table 1. — Chromosome numbers in some of the commoner Jl oners
Chromosomes
Name of flower
cells
Body
cells
Ageratum
Alyssum
Annual larkspur
Bachelor button (cornflower)
Calendula
California-poppy
Canterbury-bells
Canterbury-bells (tclraploid)
China-aster
C hrysanthcinum
Clematis
Columbine
Cockscomb
Dahlia (some types)
Number
10
8
8
12
14
6
8
10
9
9
8
7
18
10
Number
20
10
16
24
28
12
10
32
18
18
10
14
ISO
32
Chromosomes
Kamo of flower
Sex
cells
Dahlia variabilis
English daisy
Fuchsia
Lily, Easter
Lily, tiger
Nasturtium ...
Rhododendron species.
Roses, various types
Snapdragon
Stocks
Sweet peas
Sweet-w illiam
Wallflower
Zinnia
Number
32
a
n
12
14
13
,14,21
8
12
Body-
cells
Number
64
18
22
24
3f>
28
26
14,28,42
16
14
14
30
11
24
SOME PAST ACHIEVEMENTS AND FUTURE POSSIBILITIES
The fundamental principles of breeding are now fairly well established,
but the methods of application vary with different plants. The
plant breeder who is interested in flowers and ornamental plants is
faced with the problem of choosing his material from among many
hundreds of species. It is obviously impossible to work with more
than a small proportion of them. As a rule those breeders who have
accomplished the most have limited themselves to a very few.
In preparing this article, the authors also were confronted with the
task of choosing only a few representative species out of many avail-
able. In doing this it was realized that much interesting and valuable
work would necessarily be left out. To some extent this omission is
compensated for by the extensive appendix on research in flower
breeding at the end of this article. _ Those especially interested in
some flower not mentioned may find it included there.
Amaryllis
Botanically the name amaryllis should refer to the entire family
Amaryllidaceae, but horticulturally it is used for plants of a single
genus, Hippeastrum, belonging to this family.
FLOWERS 923
A watchmaker named Johnson, of Lancashire, England, is credited
with having produced in 1799 the first hybrid amaryllis recorded in
the history of this plant. Johnson had a small garden where he fol-
lowed his hobby of hybridizing plants and produced Hippeastrum
johnsoni Bury, which even by modern horticultural standards was a
distinct and outstanding variety. This hybrid is recorded as a cross
between H. reginae Herb, and H. vittatum Herb. It has since been used
a great deal as a parent in the production of other hybrid amaryllis.
It was at the end of the eighteenth century that widespread interest
began to be centered on plants of the amaryllis family. In 1821
William Herbert published a treatise on plants included in the amaryl-
lis family. This was followed in 1837 by his work entitled "Amaryl-
lidaceae", which is still considered a valuable record of the amaryllis
family. In this book Herbert lists under the genus Hippeastrum
31 "hybrid or mixed crosses" which he had secured or which had been
produced by others and brought to his attention.
The family of De Graaff, of Leiden, Netherlands, was also greatly
interested in the amaryllis at the beginning of the nineteenth century
and produced hybrids that were of importance at that time. Fol-
lowing closely was the famous English firm of James Veitch & Sons,
which introduced two handsome species from the Andes of Peru,
Hippeastrum pardinum Dombr. and H. leopoldi Dombr., which were
first flowered at Chelsea, England, in 1867 and 1869, respectively.
From these two species have come many beautiful hybrids. A fist
of those who have made noteworthy contributions to the development
of the amaryllis in the last 50 years includes such names as Arthington
Worsley in England, E. H. Krelage in the Netherlands, E. L. Holmberg
of Argentina, and Henry Nehrling and Theodore L. Mead of the
United States.
As is the case with many horticultural plants, botanists find it
difficult to classify the species and varieties of amaryllis. Because of
the way plant improvement has developed in ornamental horticulture
and the lack of records, it is impossible to trace the ancestry of the
heterogeneous and hybrid varieties of today.
A. Worsley, writing in the Gardeners' Chronicle in 1901, stated
that in his opinion a botanical classification of all the modern amaryllis
varieties would divide them into but two species. Hippeastrum vit-
tatum remains fundamentally as it existed 100 years ago, allowing for
the superiority it has attained through selection and good culture.
The other species is more difficult to trace because so many of the
original characters have been lost in breeding. The type as it is now
known has a short, well-expanded, large, substantial flower with wide
segments and the hairy throat of H. eguestre major Herb., the color
of H. eguestre Herb, and H. rutilum Herb, (rarely of H. aulicum Herb.),
and the keel markings of H. reginae. The colors are now very varied.
The rarer colors, especially the coppery reds and those nearest white,
have of late been diligently sought and selected, and hence have
increased in collections, at the expense of other colors.
It is Worsley's belief that the frequent self -colors that appear in lots
of seedlings are reversions to some ancestral type, and that the first
parents of all our parti-colored or marked flowers were selfs, and
inconspicuously colored at that.
924 YEARBOOK, 1937
The confusion in the genealogy of the amaryllis goes so far as to
shadow the parentage of the first recorded hybrid made by Johnson.
This variety is recorded in Mrs. Bury's work published in 1831 as the
progeny of Hippeastrum jormosissima X vittatum. According to J. G.
Baker's Handbook of the Amaryllideae, published in 1888, however,
II. johnsoni was raised out of H. reginae X vittatum. To Worsley both
these suppositions seem untenable, for he has never been able to hy-
bridize H. vittatum, and further he states that //. johnsoni does not
bear any resemblance to //. vittatum. Further to complicate this matter
there appear to be two distinctly different plants in the literature,
both under the name II. johnsoni. Thus down through the list of hy-
brids there are many discrepancies, resulting in confusion in any
attempts to trace the parentage of modern amaryllis varieties. Pub-
lished descriptions frequently giving incomplete information have
sometimes served further to obscure the genealogy of amaryllis.
Also to be considered is the question of sterility in hybrids. In
the past, doubtless many excellent but sterile hybrid amaryllis have
been lost because of an incomplete knowledge of means of vegetative
propagation. Fortunately the work of Ida Luyten in the Nether-
lands in 1926 has clarified many problems in connection with the
multiplication of bulbs by asexual means.
Worsley, who is known as the dean of the amaryllis fraternity,
stated in 1901 that although his efforts had been directed for many
years to producing Hippeastrum species hybrids, he could not claim
to have met with success in a single instance. He said that he was
aware of but three or four undoubted species hybrids — II. solandri-
florum X johnsoni; H. johnsoni X solandriflorum; H. pardinum X
reticulatum; and possibly II. reticulatum X vittatum. These must be
reduced to two or three if II. johnsoni is itself regarded as a species
hybrid. He acknowledged that other species hybrids have probably
been raised and the parentage left in doubt, for such species as II.
equestre, II. aulicum, and the rutilium-reginae group are all good seed
bearers when self-pollinated or when crossed with certain hybrid
forms. The fact that such hybrids already have the blood of these
species, he believed, accounts for the ease with which they cross back
with their purebred relations.
Despite the uncertainty enshrouding the lineage of many of the
varieties of modern amaryllis, breeding and selection have gone on
apace, and each year more interest is being manifested in the develop-
ment of this flower. In 1934 the American Amaryllis Society was
launched. In its constitution its aims are stated as "the promotion
of sub-order I Amarylleae, and sub-order II Alstroemerieae, order
Amaryllideae." As part of its activities this organization publishes a
yearbook, in which is attempted a complete inventory of all Amarylleae
as well as the collecting of information from all over the world on the
breeding and culture of these plants. It will contain systematic
descriptions of new varieties, which will be of tremendous importance
both historically and as an aid in breeding work in the future.
The American Amaryllis Society is also sponsoring national amaryl-
lis shows, the first of which was held at Orlando, Fla., in April 1934,
with 10,000 blooms. The varieties that attracted most attention were
FLOWERS 925
those having blossoms of pure white or a refined shade of red. The
display of amaryllis bearing yellow blossoms was not of good quality,
and more breeding and selection are necessary before a pure yellow
blossom can be secured.
In 1935 the second national amaryllis show was held at Montebello,
Calif. The hybrid types of amaryllis exhibited by commercial plant
breeders in California were the outstanding feature of this exhibition.
Apparently, striking, clear colors and large sized blossoms were the
characters that appealed most to the spectators at this show.
The national amaryllis show was held again in Orlando in 1936.
The varieties of amaryllis of Dutch origin were the outstanding display
of the exhibition. Perfection of form and color were the outstanding
qualities of these varieties.
In the Bureau of Plant Industry, breeding and selection work with
amaryllis have been conducted since ]909. The aims in this work
have been to improve existing types of amaryllis and to obtain new
colors, more shades, and a further increase in the size of the flowers,
and in numbers of flowers in clusters. In 1909, 1 2 varieties of amaryllis
were imported — Diana, Venus, Serapis, Progress, Achilles, Crimson
King, Vesta, Virgin Queen, Monarch, Bacchus, Adonis, and Scarlet
King. The colors ranged from dark red through pink to white with
red stripes.
The late E. M. Byrnes, formerly superintendent of the Department
greenhouses, undertook by cross-pollination to develop new colors
from the original flowers. In 2 years' time the plants resulting from
the crosses came into flower. Each year since 1909 this process of
selection and cross-pollination has gone on in order to produce superior
varieties.
One of the outstanding varieties of amaryllis developed at the
Department greenhouses is a pure white one. This was first exhibited
in 1920. Since that time this variety has been further improved
in size, form, and purity of color.
Each year an amaryllis exhibition is held at the Department
greenhouses. Most interest at these shows seems to be directed to
the pure white flowers and those of clear, new colors. The larger
flowers likewise attract much attention.
The literature fails to reveal any great amount of work on the
breeding of amaryllis on the basis of our present knowledge of genetics
and cytology. The fact that we have a number of supposed cases of
generic hybrids in the Amaryllidaceae has created considerable
interest, but it remains to be decided in some of these cases whether the
botanical classification of genera has been sufficiently rigid and whether
such hybrids actually are the. result of crossing two distinct genera.
It is certain that cytogenetic study will be the means of elevating
the breeding of amaryllis to a higher plane and of broadening its scope.
One of the first steps in such a plan is to acquire and make chromosome
studies of as many species as can be secured. As a result of these
studies much can be learned concerning the probable parentage of
some of our modern varieties. Again, cytological and anatomical
studies may solve problems of apparent sterility between certain
species. Chromosome studies will be of considerable help in funda-
mental taxonomic studies of the entire family Amaryllidaceae.
926 YEARBOOK, 1937
Because the amaryllis varieties are extremely heterozygous, or
hybrid, in their genetic make-up, and because they can be propagated
by vegetative means, it is questionable whether it is worth while to
breed pure-line material that is homozygous. The time element must
be considered, for with the amaryllis it takes 2 years from seed to flower
while in some of the other genera of the Amaryllidaceac the time is
much longer.
For the next decade it is probable that most now varieties will be
derived from the hybrid kinds that now exist. .However, consider-
ably more thought and effort will doubtless be directed to careful and
systematic breeding as the tools and methods of modern plant breed-
ing become better known. „ 4
China-Aster
In popularity the China-aster (Calliatephus chinensis (L.) Noes) is
not exceeded by any other cut-flower annual with the possible ex-
ception of the earlier blooming sweet pea. The size, boldness, and
attractive form of the blooms, and. the sturdy stems and free-flowering
habit, as well as the diversity of types available, contribute to its
popularity.
A single species, native to China, is included in the germs Gallia-
tephus, yet this has given rise to a range of forms equaled by few of the
garden flowers of today. The family Compositao includes tins genus
as well as Aster, the latter with a great diversity of species, and distinct
from China-asters.
A Jesuit missionary, E. P. dTncarville, introduced the China-aster
into Europe in 1731. The original form was single, with two to four
rows of ray florets of red, blue, violet, or white, and numerous yellow
disk florets. The original stature was medium tall, some 18 to
24 inches in height. The "single chinensis" type now offered by
seedsmen and thought to be the old original aster is a midseason typo,
flowering toward the end of August. Early improvement work was
concentrated in France and yielded double forms such as the peony-
flowered type. During the first half of the nineteenth century
German breeders were so active, chiefly with quilled types, that
Callistephus became known in America as the German aster. Double
forms reached England by 1752, and a variegated blue and white type
was known in 1807. By 1851 the quilled type, perfected in Germany,
was well known, and dwarf types were appearing. The Comet type,
dwarf and compact with lone flat rays and a loose flower head, was
introduced about 1886. The Queen of the Market type, notably
early flowering with wide-spreading habit and long stems adapted to
cutting, appeared in the trade about 1886 from France, where it was
already well known in the Paris markets. The Semple strain, tall
and strong, with stiff stems and large flower heads, was developed
in Pennsylvania. Other tall branching types, emphasizing strong
flower stems and large size of bloom, have been developed in the United
States for the florists' cut-flower requirements. Kecent improvement
has been accomplished chiefly by seedsmen, although the Wisconsin
Agricultural Experiment Station has taken a leading part in the
development of strains resistant to the fusarium wilt disease.
It is generally admitted that a satisfactory classificationof China-
asters, including all the forms offered by seedsmen today, is imprac-
FLOWERS 927
ticable. Bailey in 1895 offered a tentative classification based on
form of bloom and of florets. Beal lias offered a more inclusive
classification, using four classes of plant habit (tall pyramidal, tall
branching, dwarf, single) with further subdivisions based on form of
flower heads and florets. Seedsmen also employ the purpose of the
variety in making classifications, as florists' cut-flower types, with
stiff stems. One American seedsman offers nearly 200 varieties of
China-asters and a European firm offers over 500.
During the last decade increasing prevalence of two diseases, wilt
and yellows, threatened to wipe out the China-aster. Losses became
so heavy that florists and home gardeners alike were turning to other
flowers for summer and early-fall cutting, and seed sales dropped
alarmingly. Partial control of both diseases has been effected as the
result of recent research, in which the Wisconsin station has assumed
a leading role. The wilt disease, which is caused by a soil- and seed-
borne fungus of the genus Fusarium, has been conquered by selection
of strains resistant to infection. Yellows, a virus disease spread by
a species of leafhopper, may be avoided by growing plants under
special cloth shelters, which exclude the insect carrier.
Jones and Riker (274) began selection of wilt-resistant asters in
1925. Commercial varieties were grown in "aster-sick" soil, thor-
oughly contaminated with Fusarium as a result of repeated aster
culture. No one of the commercial varieties proved to be uniformly
resistant to wilt, but resistant individuals appeared among most of
tho types tested. Selection was continued in the progeny of resistant
plants through 1930. Beginning with 1929, extensive testing and
selection were carried, out at the Bodger Seed Co. farms at El Monte,
Calif. Earlier efforts were concentrated on several flower colors in
the American Branching group and on the Heart of France variety,
but later study has shown that resistant lines are available within
other desirable types of asters such as the Semple, American Beauty,
Comet, and Royal types. Seedsmen now advertise resistant asters
of all major groups except the pompons. Commercial resistant
strains, maintained by selection each year, are rarely 100-percent
resistant, but represent a marked advance over the unselected varieties.
In the reports on development and improvement of China-asters no
mention of artificial hybridization has been found. Furthermore, the
genetics of Callistephus seems to have been wholly ignored except for
one record of an apparent mutant defect in the ray florets of a single
form. All the characteristics we have in Callistephus today— diverse
plant form and stature, divergent form and color of bloom, varying
dates of maturity, resistance and susceptibility to wilt — have evi-
dently arisen from the old original type of the species by spontaneous
mutation and chance hybridization. All that man has done to im-
prove the aster consists in growing it in immense numbers and in
saving those segregates and mutants that have appealed to him as
desirable.
The complete range of color now available was obtained years ago.
Improvement since the early days has taken place chieffy in form of
flower (fig. 16) and in plant habit. The ordinary procedure consists
in saving seeds of natural variants, usually produced without protec-
tion against crossing with neighboring varieties. After a few years of
928
) EARBOOK, 1937
Figure 16. — A few of the many forms of asters now available: A, Mammoth or Gianl
of California; B, Early or Late Beauty; C, Unicorn or Ray; D, King; E, Ostrich
Plume; F, Queen of the Market; G, American Branching; //, Sunshine; /, Ilohen-
zollern; J, Victoria; K, Tres Naive.
selection the type becomes fixed for the new character, with color
variants still appearing within it. Colors are in turn fixed by further
selection. As an example, the Comet type appeared on the market in
FLOWERS 929
1886 as a pale pink fading to white. Six years later, rose, blue, and
pure white Comet types were offered. It is commonly assumed that
the percentage of natural crossing in asters is low, but Fleming (131)
estimated that approximately 10 percent of natural crossing occurred
at Summerland; British Columbia. In the earlier Wisconsin work on
wilt resistance, individual plant selection was practiced under cages to
exclude leaf hoppers, which also insured a high degree of self-pollination.
Fleming grew the progeny of rogues in rows adjacent to the com-
mercial strains from which the rogues were derived. From the varia-
tion shown by these open-pollinated rogue types in the next generation
he presents certain tentative conclusions with respect to color domi-
nance: white is recessive to all or to most colors; purple is dominant
to red, and red to white; deep pink is dominant to white.
In future breeding of the China-aster the most important single
characteristic to be sought is resistance to yellows. The search for a
yellows-resistant type is complicated by the fact that affected plants
develop no viable seed; hence a partially resistant type cannot be
continued as a line selection. White (544) has noted that the Queen
ofthe Market type, although susceptible, appears to be less severely
injured by the disease than later sorts. Development of homozygous,
or pure, lines by self-pollination will aid materially in segregating
desirable qualities and. will permit genetic analysis of such characters
as color and habit. „
Canna
When cannas were first recognized as suitable for ornamental
purposes, they were tall leafy plants with comparatively small flowers
and considerable space between nodes. A chronological history shows
that Canna indica L. was introcraced into England by Gerard in 1596.
In 1762 Linnaeus listed but three species. Roscoe in 1828 admitted
21 species. Between 1830 and 1850 the younger Bouche, in Berlin,
estimated the number of species at 82." Between 1840 and 1865
Annee in France developed a race of garden types from O. nepalensis
Wall, with pollen probably from C. glauca L. This hybrid was called
O. annaei Andre. Dwarfer cannas with larger flowers appeared when
a cross was made by Annee in 1863 of C. iridiflora Ruiz and Pav. with
G. warscewiczi Dietr.
From this point on, the interest in securing newer and better types
increased rapidly, and there were many horticultural forms developed.
As tastes for bedding cannas changed, the new varieties entering into
commerce were dwarfer and the flowers larger and of higher quality.
Because such types had been originally developed as a result of the
work of plantsmen in France, the dwarf kinds are known as French, or
Crozy, cannas. The latter name is used because many of the superior
types were sent out by Crozy and Sisley of Lyons. Vilmorin of
Antibes, Lemoine of Nancy, and Maron of Saint-Germain-les-Corbeil
have all contributed to the garden canna as we know it today.
More recent than French cannas are the Italian or so-called orchid-
flowered types. The latter name is employed because the flowers of
these new cannas resemble the flower of an expanded Cattleya orchid.
These varieties were first developed in Italy by M. Dammann & Co.,
at San Giovanni a'Teduccio, Naples. The Italian varieties are
recorded as crosses of Carina flaccida Salisb., a native of the southern
930 YEARBOOK, 193 7
United States, with garden forms and with O. iridiflora. They show
improvement in the flowers, which have soft flowing margins and
superior colors of golden vermilion.
During the latter part of the nineteenth century new canna varieties
were being brought into the United States in large numbers. In 1893
Wintzer (555), of West Grove, Pa., became interested in the develop-
ment of new varieties, with the object of improving the strain and
developing new and desirable varieties suitable for ' 'our trying climate."
Wintzer was particularly interested in producing a canna with a clear
yellow bloom. As a result of continued hybridization and selection he
developed the variety Buttercup. It was rather dwarf, early, and a
free bloomer, held its flowers well above the foliage, dropped the faded
ones, and the blossoms endured the sun without bleaching. Another
quality that Wintzer attempted to develop in cannas was the produc-
tion of rootstocks that would store well during long winters. He
developed two pink-flowered varieties, Martha Washington and Betsy
Ross, with small, hard rootstocks, a type resistant to decay in storage.
Some of Wintzer's best varieties, including the white Mont Blanc,
have resulted from using seedlings that were of no merit commercially
but carried characters that he wished to introduce into the progeny.
It is possible that in anotherdecade the breeding of new canna varieties
will be again stirmilated and advanced by new practices and techniques.
The varieties of ornamental cannas offered in the trade today repre-
sent types that show great improvement over the original botanical
species. There was a time about the beginning of the twentieth
century when cannas were much in demand for the extensive bedding
work that was then the mode in public parks, cemeteries, and other
landscaped areas. In an effort to produce new forms and colors,
gardeners year after year hybridized plants with desirable character-
istics. In the last 20 years the popularity of bedding plants has
waned, and consequently, many of the canna varieties have been lost.
This makes a reconstruction of the lineage of the remaining varieties
more difficult because many of the intermediate types between the
true species and the modern complex hybrids have disappeared.
Even earlier, as a result of the mixing of species due to hybridization,
there was considerable confusion in regard to the classification of
canna varieties and the parentage of the varieties then in the trade.
J. G. Baker, in England, writing in the Gardeners' Chronicle in 1893,
concluded from a study of the canna literature from every available
source, that the least conservative estimate could not give the genus
Canna more than 16 species, although 90 had been listed previously.
Granting that this confusion existed nearly a half century ago, activi-
ties of the last 50 years have done little more with canna classification
than to aggravate the situation.
In recent years the canna has received attention in the technical
field of cytogenetics. Honing {213) in the Netherlands, Belling (46)
in the United States, and Tokugawa and Kuwada (513) in Japan
have made contributions to the studies of inheritance in the canna.
The work of these men contributes knowledge of practical nature,
which can be adapted to the development of superior varieties of
cannas for ornamental purposes. These studies have pointed out the
advantages and shortcomings of triploid varieties in the canna, a type
FLOWERS 931
which is desirable as an ornamental but usually not suitable for further
breeding work. More details of the nature of triploid plants can be
found in the paragraphs devoted to genetics earlier in this article.
Belling (£5) in 1921 studied the behavior of homologous chromo-
somes in a triploid canna. This variety he secured under the name
Gladiator. To the horticulturist it was a noteworthy variety, for it
was sterile and the flowers, instead of setting seeds, dropped after they
had matured and gave way to new blossoms. The production of seeds
in ordinary fertile, diploid cannas is a detriment to continued flowering.
In nearly all cases triploid varieties are partially or totally
sterile and thus often incapable of hybridization. In the past much
time and labor have been expended in fruitless attempts to cross
ornamental plants where one or both of the desired parents used were
sterile and incapable of contributing to the production of hybrids.
The work of Belling on cannas points out limitations and also oppor-
tunities in future breeding work with this plant.
Fortunately for the horticulturist, the canna is readily propagated
vegetatively; consequently plants with sterile flowers, if worthy of
perpetuation, can be increased in this way. Belling did find, however,
that most of the 46 clones of cannas that he investigated had the diploid
number of chromosomes, which is nine pairs in somatic cells. It
would be from varieties of cannas with the normal nine pairs of
chromosomes that high interfertility could be expected in connection
with the development of new varieties.
Honing, working in the Netherlands, has published a series of papers
since 1914, all concerned with technical genetical studies of the canna.
He has reported on the inheritance of pigment in stems, leaves, and
fruit papillae of Canna indica. As a result of crossing C. indica with
C. glauca he obtained a single hybrid plant that in subsequent gen-
erations gave progeny that differed widely among different sowings for
the factors of red leaf margins, wax layers on the leaves, and the
number and color of staminodes. He also made a genie analysis of
the inheritance of flower and leaf characters in the cross mentioned
above.
At the Tokugawa Biological Institute, Tokyo, Japan, cytological
studies were made on some garden varieties of cannas by Yoshichika
Tokugawa and Yoshinari Kuwada. A report of their work was
published in the Japanese Journal of Botany in 1924. It included a
study of the chromosome number of various varieties of garden cannas.
They found that there were either 18 (diploid) or 27 (triploid) chromo-
somes in the varieties coining under their observation.
These cytological studies in Japan also pointed out that the process
of meiosis in canna is generally of somewhat abnormal tendency both
in the diploid and triploid varieties. This abnormality of division is
possibly the cause of some sterility, which is well recognized in certain
canna varieties. Finally the work of Tokugawa and Kuwada showed
conclusively that the triploid cannas are larger than the diploids with
respect to the stomata openings of the leaves, the size of the cells of
the epidermis of the staminodia, the thickness of the leaves, and
lastly, the size of the entire flowers. It was also noted that the
staminodia of the triploid plants not only are larger than those of the
diploid plants but also present a desirable delicate wavy appearance
932 YEARBOOK, 1937
in their surface. While this Japanese paper is a technical treatise, it
serves as a valuable addition to the knowledge that a practical breeder
of cannas must have to carry on his work effectively.
Carnation
The carnation (Dianthus caryophyllusL.) is one of the oldest flowers
still under cultivation. It was first mentioned and described in 300
B. C. by a Greek philosopher, Theophrastus. The original type was a
single flower with five petals, measuring about 1 inch in diameter and
of a pinkish-mauve color. It grew wild over much of Europe, and it
still existed in Normandy as late as 1874.
In England, during the reign of Queen Elizabeth, William Turner
published an extensive description of this flower. By this time the
double form had made its appearance and already existed in a wide
range of colors. Just when or how the double form arose will probably
remain an unsolved mystery. The flower was very popular in Eng-
land, and early in the eighteenth century it was used in a successful
cross with sweet-william. Most of the early selection work was
done by English amateurs, who rapidly developed a wide range of
forms and colors. They were interested both in the outdoor garden
types and in the large, double-flowered varieties of the florists. In
this article the discussion deals almost entirely with the latter type,
which is now one of the most important flowers grown under glass in
this country.
The florists' carnation occurs in three distinct forms, the single,
the double, and the superdouble, or bullhead. The second type includes
all the commercial varieties. The bullheads are so extremely double
that the calyx splits badly as the flower expands. The first published
report that threw some light on the question of inheritance of double-
ness appeared as an abstract in the 1904 Proceedings of the American
Society for Horticultural Science. At that time Norton (896), of the
Department of Agriculture, told of some experiments he was carrying
on in the breeding of carnations. He reported that from the seed of
individual capsules he secured all three types of carnation flowers.
From one there were 6 doubles (bullheads), 15 semidoubles (commer-
cials), and 7 singles; from another 74 doubles, 147 semidoubles, and
52 singles. These proportions are approximately 1 to 2 to 1, and they
agree fully with what is expected in the progeny from a hybrid when
one of the two genes affecting the same character is not fully domi-
nant to the other. At that time Norton suggested that the practical
florist should cross the single with the extreme double type and thus
secure a greater proportion of intermediate true florists' types. The
common practice, which still persists, was to cross two commercial
double varieties, and always a large proportion of resulting seedlings
were singles and bullheads.
In 1907, at the meeting of the American Breeders' Association,
Norton (397) reported that several crosses between singles and extreme
doubles, made in 1905-06, yielded 250 seedlings, which were, with
one exception, commercial doubles. Since no protection from outside
pollen was used, the one single seedling may have been an outcross.
It was pointed out that single and very double seedlings were
usually discarded no matter how desirable their other characters
FLOWERS 933
might be. By pollinating a good single with the pollen of an extreme
double that has some new desirable quality, a complete series of
standard double seedlings can be secured, some of which may show
the new character.
In 1912 Stuart (498) presented a more comprehensive publication
on this question. The breeding work, begun at the Vermont Agri-
cultural Experiment Station, was completed at the Arlington Experi-
ment Farm, Arlington, Va., after Stuart joined the staff of the Depart-
ment. The earlier work of Norton was confirmed and the following
facts established: When a single was crossed with a single, all the
hybrids were singles; a single crossed with a commercial double gave
about 1 single to 1 commercial, but when crossed with a bullhead it
gave practically all commercial doubles; when 2 commercial doubles
were crossed they gave about 1 single to 3 doubles. Unfortunately
the doubles in Stuart's report were not classified as to bullheads and
commercial types.
The results were analyzed as follows: (1) The commercial carnation
as grown by florists is an unfixed hybrid from a cross between a single
and superdouble; (2) the bullhead type is incompletely dominant to
the single, and the hybrid resulting from crossing them is the inter-
mediate or so-called commercial double.
Unfortunately, the development of superior double carnations is
not so simple as the preceding account seems to indicate. Frequently
the investigator is hampered by having abnormal plants appear in
his progenies, from which very little or no seed can be secured. Ac-
cording to Connors (81) and his associates, who carried on carnation
breeding at the New Jersey Agricultural Experiment Station for 15
years, there are many types of carnations with respect to the relative
development of pistils and stamens. These types include plants
bearing male flowers only, plants with all stamens transformed into
petals, and asexual types in which pistils and stamens are rudimen-
tary and nonfunctional. It was possible to further subdivide these
groups so that 10 types in all are recognized.
In spite of the many difficulties and the meager information on
inheritance in the carnation, a very large number of choice varieties
have originated as seedlings. Many florists have devoted considerable
space and time to this work. One of the leaders was Ward, who
devoted considerable time to the production of better florist types
and presented his observations on carnation breeding (588). At
that time he stated that in raising varieties from hybrid seed very
few improvements are produced. lie estimated that only about 1
in 1,000 seedlings had any merit, and probably but 1 in 5,000 or
10,000 was a decided advance. He also felt that even this low fre-
quency would decrease rather than increase because of the higher
standard that was set from year to year.
The list of seedling varieties is constantly changing as old ones are
replaced by newer and better types. It has been the practice of many
commercial growers to try out a small number of some of the new
ones each year. It may happen that one from New England is very
inferior in the Colorado section, and one from Colorado may lack
quality in Illinois. This has demonstrated, in this country, that it is
necessary to develop varieties for a given locality.
934 YEARBOOK, 1937
Many carnation varieties originate as bud sports. It is a relatively
simple matter to propagate these if desirable. These sudden changes
may affect any part of the plant. Sometimes the leaves are broader,
or deeper or lighter green, or the plant is d warier, more compact, or
taller. The flower may be modified as to color, size, length of stem,
or structure of petals. Since the flower is of primary importance,
bud sports are most likely to be noticed when floral characters are
involved.
Unfortunately there is no authentic evidence on the frequency of
bud sports in carnations. Isolated observations in various sections of
the country seemed to indicate, however, that they might occur at
a rather high rate. Unquestionably many of the best of our current
varieties arose in that way. As a result growers have become accus-
tomed to keeping a careful watch over their benches during the growing
season. Since, under the stress of commercial operations, there is
always the possibility of mechanical mixture of rooted cuttings, it is
impossible to give an accurate account of the situation.
There are a number of carnation disease problems in the solution
of which the plant breeder should be useful. Two of these diseases,
carnation rust (Uromyces caryophyllinus (Schrank) Wint.) and stem
rot (Corticium vagum B. and C.) may at times become very trouble-
some. Varieties resistant to these diseases, provided they were also
of high quality, would be very acceptable. There is some evidence
that resistance to rust already exists in some of the better commercial
varieties. In 1932, a test of 36 varieties was made at the Waltham
Field Station, in Massachusetts, and they were grouped for rust
resistance as very susceptible, moderately susceptible, slightly
susceptible, and resistant. The standards for grading resistance were
not stated, nor wore the severity and uniformity of the infection given.
The problem of color inheritance has received very little attention
as yet. The highly heterozygous conditions of the carnation and
the very frequent functional sterilities encountered have discouraged
research along these lines. As facilities for flower breeding are in-
creased, it is likely that some attention will be given to these problems.
The condition known as carnation splitting is another problem that
should receive more attention from the flower breeder. It was
studied by Connors, who stated that it was caused by two conditions — ■
the formation of an unusually large number of petals through trans-
formation of stamens and pistils, and the development and growth
of secondary buds within the flower.
As early as 1903, Ward had assumed that splitting was entirely
hereditary, and he advised the selection of seedlings that produced
flowers with an unsplit calyx. Later, Connors stated that the ex-
perience of the New Jersey station indicated splitting was influenced
by both hereditary and environmental factors. It is needless to say
that a good nonsplitting variety would be a valuable contribution.
Since there is a rather definite regional adaptation of varieties, it
seems that a sound carnation breeding program should include
facilities for testing all seedlings in as many different locations as
possible. When the work is carried on at only one location, there is
loss from discarding seedlings that might prove A'ery valuable in
another region.
FLOWERS 935
Chrysanthemum
The culture of improved forms of chrysanthemums antedates the
beginning of the Christian era by several centuries. Apparently
they are native to China, and are mentioned in Chinese literature as
early as 500 B. C. The Japanese grew them extensively at an early
period and did considerable work in developing improved types. A
form with 16 petals was chosen as the flower emblem of the Emperor.
In both China and Japan, single-stemmed varieties were generally
grown long before the plant was introduced into western Europe.
The earliest record of chrysanthemums in Europe is of an im-
portation in 1688. It seems strange that this attractive flower was
not known to Europeans at an earlier period. The following year
several varieties were reported as being grown in the Netherlands,
but for some unknown reason they soon passed out of cultivation.
It was not until 1764 that chrysanthemums made their appearance
in England. They soon became popular, and additional varieties
were imported from China in 1789. During the following 20 years,
eight new types were introduced from China.
All the early varieties introduced into Europe were brought in as
living plants. The first attempts to grow seedlings were not made
until about 1827. At this time a Frenchman, M. Bernet, flowered
several fine seedlings from seed he found in withered flower heads the
previous autumn. Following this it is very probable that many
amateurs began to grow seedlings, but unfortunately we have no
records of any new developments.
In 1846 Robert Fortune brought two small-flowered varieties from
China and introduced them into English gardens. They were not
well received by the English, but when sent to France they soon
became rather popular and were used extensively in hybridizing. It
seems probable they were the progenitors of our modern small-
flowered varieties.
The early history of chrysanthemums in the United States is rather
obscure. According to the 1828 catalog of William Prince, they were
introduced into Hoboken by John Stevens in 1798. The plants
were probably a dark purple form, which had reached Europe from
China in 1790. In 1826 the Prince's Nursery listed 26 varieties,
and by 1835, according to Hovey's American Gardener's Magazine
and Register, 50 distinct varieties were available in this country.
There is no record of the origin of any of these early chrysanthe-
mums. Propagation by cuttings was very simple, and strains were
perpetuated in this way. Undoubtedly this was a strong factor in
retarding breeding. The fact that so few different types existed in
this country in 1835 is an indication that very little actual improve-
ment by breeding had been attempted.
One of the earliest breeders in this country was Robert Kilvington,
of Philadelphia, who exhibited a new seedling named William Penn
before the Pennsylvania Horticultural Society in 1841. It was a
large white double flower, almost globular in shape. It seems strange
that this did not immediately stimulate more work, but no other
contributions appeared for some time. About 1850 Samuel Brookes,
of Chicago, became very much interested in chrysanthemums and did
considerable work to stimulate interest in the flower.
936 YEARBOOK, 1937
A general interest in chrysanthemums was slow to develop in this
country. In 1844 an impressive display was made of many of the
available varieties at the fall show of the Massachusetts Horticultural
Society. Two years later there was a large exhibit before the Penn-
sylvania Horticultural Society, where the chrysanthemum was
described as the coming flower. A special chrysanthemum show was
not held, however, until 1868. At present there are many chrysan-
themum exhibits each year.
Previous to 1850, chrysanthemums were not grown as greenhouse
plants. About this time a few varieties were tried under glass, and
development of special florists' types was soon under way. The
development of this branch of the florists' business soon extended the
blooming period and made it possible to market the large showy types
that were being introduced from Japan. About 1883, Hosea Waterer
imported about 50 varieties from Japan. Shortly following this, a
large white variety appeared that was so attractive it is saidto have
been sold for a fabulous sum. This variety was sent to Mr. and
Mrs. Alpheus Hardy by an appreciative friend in Japan. It was
named Mrs. Alpheus Hardy and undoubtedly was one of the stimulat-
ing influences that led to a quickening of interest in chrysanthemum
breeding in this country. Some of the successful breeders of this
period were T. H. Spaulding, E. Fewkes, Pitcher & Manda, V. H.
Hallock, W. C. Pyfer, E. G. Hill, and F. Dorner & Son. By 1894,
there "were listed 163 varieties of American origin.
In the latter years of the past century, one of the most prolific of
modern chrysanthemum breeders, Elmer D. Smith, of Adrian, Mich.,
began his work. He had introduced 445 new varieties by 1928, and
many others have been added since that time. Other American
breeders who contributed many new chrysanthemums during this
period are E. M. and J. W. Byrnes and F. L. Mulford, of the Depart-
ment of Agriculture. More recent entrants in the work have been
V. R. De Petris, of Detroit, Mich., and Alex Cumming, Jr., of Bristol,
Conn., who has specialized with outdoor chrysanthemums.
The efforts of these breeders have been mainly to develop green-
house or so-called forcing chrysanthemums. A program to develop
hardy outdoor types has been under way in the Department for some
time. The work was started by growing outdoors as extensive a col-
lection of varieties as possible, and securing data on their time of bloom
and winter hardiness. The work was carried on at first at the Arling-
ton Experiment Farm, but in recent years certain selections have been
sent to various cooperating State experiment stations for triai. By
selecting each year the earlier flowering types and growing seedlings
from them, races have been developed that bloom as early as July in
the vicinity of Washington, D. C. (fig. 17). The earliest strains are
followed successively by others until heavy frosts kill the plants.
The work has demonstrated very clearly that time of bloom is actually
a hereditary trait transmitted from parents to seedlings.
The problems involved in chrysanthemum breeding are to some
extent very similar to those faced by the rose breeder. The history of
the early chrysanthemum varieties is not known, but it seems likely
that most of them arose as mutations or bud sports from other varie-
ties. While there are no data on this point, the evidence all points in
FLOWERS 937
that direction. So far as can be determined, little or no breeding
work was attempted in China or Japan, and all varieties were main-
tained by the rooting of cuttings. If a new color or other bud sport
appeared, it was simply increased by cuttings and soon became
established. Had the Japanese and Chinese been growing seedlings
there would certainly have been many more varieties available in
Figure 17. — The chrysanthemum breeding plot at the United States Horticultural
Station, Beltsville, Md., where hardy early-blooming varieties are being developed
Already a wide range of types and colors have been developed, and the blooming date
continues from late July to killing frosts. In the background are cages built over 8
plants to protect them from cross-pollination.
those countries when the flower was first brought to Europe. This
point is strikingly confirmed by the fact that Smith was able to
develop over 450 new seedling varieties in a little over 30 years. Some
of these may have been bud sports, but by far the larger number
were seedlings.
The keeping of parentage records has been fairly thoroughly done
by some breeders. Since the modern chrysanthemum is really of
rather recent origin, and probably does not involve a very complex
mixture of species, such records should have some value. If they all
were available it seems very likely they would show that certain
parents produce more good seedlings than others. While there is
little or no scientific data on the inheritance of plant characters in
chrysanthemums, breeders have learned through experience that cer-
tain varieties are likely to transmit their flower color. The variety
Harvard, for example, usually produces red seedlings in crosses, and
Thanksgiving Pink transmits its pink color. These observations seem
138904°— 37 00
938 YEARBOOK, 1937
to indicate a probable dominance of these colors over other shades, and
also that these varieties may be pure for their respective colors.
One of the greatest difficulties encountered by the chrysanthemum
breeder is the failure of many fine varieties to set much seed. In some
instances this may be due to an actual sterility, but it is generally the
result of the extreme doubleness of the flower. Not much can be
done about this unless a single can be found, which when crossed with
a double gives all double seedlings. Under such conditions, all
crosses could be made with the single as maternal parent.
The production of bud sports or mutations has also played a rather
important role in the development of the chrysanthemum. The
mutation tendency is undoubtedly higher in some varieties than in
others. In the absence of any scientific data we are forced to rely on
general observations as to the frequency of such changes. According
to some growers, the sport of a variety very frequently reverts to the
parent type. The mutations that have been observed are mostly
flower color changes. Very probably there are others affecting foliage
and other characters.
- The possible causes underlying the sudden appearances of bud
sports are mentioned in another section of. this article. If more were
known about them we might be able to produce controlled mutations
in greater numbers. If they result from some environmental influence,
then varieties of chrysanthemum must differ markedly in their re-
sponse to it, because some varieties mutate more readily than others.
This indicates an inherent mutation tendency. In other words,
chrysanthemums may have some rather unstable characters and may
mutate under certain environmental conditions.
Dahlia
Francisco Hernandez, physician to Philip II of Spain, was sent on
an expedition to New Spain (Mexico) in 1570. The purpose of this
journey into the New World was to study the natural history of this
intriguing land to the westward. After Hernandez returned to Spain
he published in 1615 four books on the plants and animals of Mexico.
In one of these books he described three types of plants which nearly
200 years later were to be called dahlias. To these three plants he
gave the Aztec names acocotli, cocoxochitl, and acocoxocbitl, which
mean, respectively, "water pipe", "hollow-stem flower", and "water-
pipe flower", the allusion being to the hollow stems of the plants.
From Hernandez's writings it is apparent that the Aztecs had
worked on the improA-ement of these plants, for this report indicates
that they varied in color, form, and degree of doubleness. The illus-
trations he published show that somewhat double dahlia flowers existed
in Mexico in the sixteenth century.
Vitalis Mascardi in 1651 published a work in Rome in which there
is an illustration of a double-flowered dahlia. Again, in 1787, a
Frenchman, Nicholas Joseph Thiery de Menonville, searching in
North America for the valued cochineal bug, described dahlias, grow-
ing in a garden near Oaxaca, which had large asterlike flowers, stems
as tall as a man, and leaves like those of an elder tree.
It was not until after 1 789, however, that the Old World awakened
to the possibilities of the dahlia as an ornamental plant. In this year
FLOWERS 939
Vincente Cervantes, director of the Mexican Botanic Gardens, sent
to the Royal Gardens in Madrid seed of dahlias from Mexico which
were destined to play a tremendous part in the development of the
superior types of garden dahlias as we know them today. It was to
Abbe Cavanilles, director of the Royal Gardens, that these seed were
sent, and from them were produced flowers of brilliant hues typical
of the dahlias to be found growing in Mexico.
Cavanilles named this plant, which was practically unknown in
Europe, Dahlia, after Andreas Dahl, an eminent Swedish botanist
living in Berlin, who had been a pupil of the great Linnaeus. Among
the plants that Cavanilles received from Mexico he recognized two
species, Dahlia pinnate. Cav. and D. coccinea Cav. The former,
which showed great variation in its progeny, lias since been called
D. variabilis Desf. and D. rosea Cav., but according to the rules of
botanical nomenclature the name D. pinnata must stand. D. coccinea
does not cross readily with other species, and its flower color is confined
to scarlet and shades of orange.
At the time Cavanilles received the shipment of dahlias from Mexico
a great deal of interest was being manifested by botanists and plants-
men of Europe in plants from the New World. Within a few years
seeds of the dahlia were sent to a number of botanic and private gar-
dens in Europe. In 1798 seeds were sent to Kew Gardens in England,
but apparently plants from the seeds died before they reached matur-
ity. _ By 1803 an English plantsman had flowered" Dahlia coccinea,
for in Curtis' Botanical Magazine of 1804 appeared a colored figure
with the statement, "Our drawing was taken in June 1803 at Mrs.
Eraser's, of Sloane-Square, who has the credit of introducing this orna-
mental plant among us from France."
From 1804 to 1806, shortly after Alexander von Humboldt sent seed
from Mexico to Paris and Berlin, a phenomenal increase in the number
of dahlia varieties occurred. Within 12 years nearly every color
that we have today had appeared in the flowers. In 1806 the Berlin
Botanic Gardens had growing 55 single and semidouble varieties.
Two years later the first perfect double dahlia was raised by Hartweg
at Karlsruhe, and the year following a variety with single white
flowers was developed.
By about 1810 the dahlia became exceedingly popular and growers
sought assiduously to improve and create better double flowers within
the genus. Both in the British Isles and on the Continent new forms,
showing doubleness and brilliant colors, were developed. In the
Botanical Magazine for 1817 an illustration revealed a rose-colored
dahlia that originated in France and showed the form of the decorative
dahlia as the type is now known.
From 1810 to 1850 interest in the dahlia increased tremendously.
The ease with which hybrid seed could be secured, because of rela-
tively self-sterile flowers, the short time required to produce new
varieties, and the extreme variation secured both in sizes and colors
of the flowers all contributed to the popularity of this new plant. Of
particular interest in revealing the quality of dahlia varieties of that
time is The Annual Dahlia Register for 1836. This contains particu-
lars of the introduction of the dahlia into England and, most impor-
tant, has as illustrations upward of 50 highly colored figures of dis-
940 YEARBOOK, 1937
similar dahlias. It also contains an index of 700 varieties of the dahlia
that were recognized as such at that time. The illustrations in this
book show double flowers exclusively, all with a colorful array of petals
in very dense, round heads, arranged very geometrically. It was this
stiff, formal, double flower that was so popular in the first half of the
nineteenth century, and the type in which interest waned to a marked
degree in Europe shortly afterward.
Seed of the modest dahlias that had been sent abroad from North
America were returned to their native shores and yielded plants
with flowers of an endless array of color patterns and degrees of
doubleness. In the United States the craze for new dahlia varieties
was nearly as acute as it was in Europe, and likewise, interest in the
stiff, formal flower began to wane about 1860.
The first National Dahlia Society was organized in Great Britain in
1870, and about that time the diminutive pompon type of dahlia was
developed, but these two events did not serve to recreate any great
amount of interest in varieties then existing.
About 1864, however, an event happened that brought renewed
interest in the dahlia through the discovery of a species with char-
acters far different from and superior in many ways to those in the
dahlia varieties known at that time. One M. J. T. Berg, of the
Netherlands, received a collection of plants from Mexico. Included
in this shipment was one dahlia root with just sufficient reserve food
remaining within it to send up one shoot. In the fall this shoot pro-
duced a brilliant, blood-red flower of a shape never before recorded.
The quilled petals, typical of the dahlia of that time, were lacking, and
in their places were petals that were recurved, with pointed ends. The
plant was tall and sturdy and carried its flower w ell above the foliage.
This new dahlia Mas given the name Dahlia juarezii Hort. in honor
of the then President of Mexico. It received the name "cactus
dahlia" because of its resemblance in form and color to the blossoms
of a cactus. This plant was to play an important part in the develop-
ment of superior varieties and to become the progenitor of two new-
classes of dahlias, now collectively referred to as the cactus and
hybrid-cactus types. The species reached England and was first
illustrated in the Gardeners' Chronicle in 1879.
All efforts to trace the origin of this new dahlia failed until 1916,
when Wilson Popenoe discovered the probable ancestral home of
Dahlia juarezii in Guatemala. The primitive species he found there
has a single row of eight long, spreading, crimson rays turning back-
ward along the margin. This species was named D. popenovi, and
it is believed to be one of the ancestors of D. juarezii.
It was fortunate that Dahlia juarezii was discovered, for in the
latter part of the nineteenth century there was, both in the United
States and abroad, a reaction against formalism in all arts. The
stiff formal dahlia flowers that had been the rage for the past half
century were outmoded. This served as a challenge to the breeders
of dahlias, and, having in their possession a new species of dahlia
exhibiting characters that were in demand, they began to breed new
varieties to suit the public's fancy.
This activity went on for a number of years, and the progeny
resulting from crosses with the new-found Dahlia juarezii created
FLOWERS 941
great interest, particularly at dahlia exhibitions. The very fact that
the flowers were displayed mostly at flower shows, however, ultimately
created still another problem for the plant breeder. Interest had
been centered chiefly in new and superior blossoms, while the structure
of the plant upon which these flowers were borne was neglected.
Consequently the new varieties possessed very weak stems and were
suitable only for cut-flower exhibition purposes. As interest in
outdoor displays developed, breeders were faced .with the task of
increasing plant vigor to reach parity with the excellence of flower
quality.
Within the last 20 years much has been accomplished in securing
superior varieties of dahlias. Varieties having weak short stems have
gradually been supplanted by more vigorous types, and breeding has
reached a high level. The number of named varieties now existing
is well over 7,000, for in 1924 J. B. S. Norton published a book entitled
"Seven Thousand Dahlias in Cultivation", and the number has been
added to greatly since that time.
Many dahlia societies have been organized in both the United States
and Europe and these have stimulated interest in the improvement of
dahlia varieties. In the United States the American Dahlia Society
has functioned for two decades. One of its outstanding activities is
the publication of a quarterly bulletin dealing with all aspects of the
culture and breeding of the dahlia. This organization also stimulates
interest in the development of superior varieties by conducting flower
exhibitions and trial gardens where new varieties are grown, eval-
uated, and exhibited.
These developments have led to considerable confusion in attempts
to classify, especially for exhibition purposes, the various garden types
now existing. In an effort to simplify the classification of the host of
new varieties that have been developed, the American Dahlia Society
had adopted a classification based on the form and size of the flower.
Fourteen classes are provided for the systematic arrangement of all
the various types of dahlia flowers. A number of these classes are
subdivided according to the size of the flower.
Other countries also have their classifications for dahlias. A great
deal of pioneer work in this direction was performed by the Eoyal
Horticultural Society and the National Dahlia Society in Great
Britain.
Worthy of special comment in considering the development of
superior dahlia varieties are the trial grounds where new varieties are
grown, studied, and evaluated. The American Dahlia Society has
such a garden in cooperation with the Connecticut State College at
Storrs. Each year a field day is held at the trial grounds, when new
varieties are inspected and evaluated. Competent judges pass on the
merits of each new variety, and thus the value of new kinds can be
impartially reported to those interested in dahlias. Other trial
grounds are conducted by State and regional dahlia organizations;
these plots permit the study of the same variety under varied climatic
and other environmental factors.
Scientific research has revealed in the dahlia an interesting story of
the inheritance of color. In the comparatively new field of cytogenet-
ics, investigations conducted by Lawrence (310, 811), curator, the John
942 YEARBOOK, 1937
Innes Horticultural Institution, Merton, England, are noteworthy.
This work indicates how the lineage of dahlia species and varieties can
be studied by modern scientific methods. Lawrence found that the
colors in all available dahlia species fall into one of two color groups:
(1) Pale to deep magenta over ivory-white ground color, and (2) orange
to scarlet over yellow ground color. One important exception Law-
rence noted was that in the so-called species Dahlia pinnata, more
popularly known as D. variabilis, which is considered the source of
most of the garden varieties, the flower color is made up of a combi-
nation of both of these color groups. Furthermore, through cytological
studies, he found that this same plant has 64 chromosomes in the
vegetative cells, or twice the number usually found in species of the
dahlia. These two facts indicated that D. pinnata is itself a hybrid.
Such work, besides aiding the taxonomist in systematizing dahlia
nomenclature, is of value to plant breeders in their efforts to produce
superior varieties of plants.
Lawrence's work also dispelled the widespread erroneous belief that
the extreme variation of Dahlia pinnata showed the degree to which
a species could vary following domestication. This extreme variation
was shown to result from the complex genetic make-up of a hybrid
which combined various specific characters brought together during
the descent of the genus Dahlia from a primeval stock. This coupled
with multiplication of chromosome numbers probably accounts for
the present variability of the stock.
The dahlia, like many other perennial ornamental plants, is readily
propagated vegetatively. As a consequence it is not necessary to
develop lines that are pure or homozygous, as is necessary with plants
propagated from seed, in order to perpetuate the same characters in
subsequent generations. Ease of vegetative propagation of the dahlia
is particularly fortunate because its self-sterility enforces cross-
pollination, thereby maintaining a high degree of hybridity in the
genus and making pure-line breeding laborious and difficult. Despite
these complications, however, the development of reasonably pure-
breeding stocks may have to be undertaken in the future by plant
breeders, not so much in order to produce dahlias of superior orna-
mental value as to develop types resistant to or immune from plant
pests. „
1 Gladiolus
The superior varieties of gladioli grown today have been developed
largely through work that began scarcely more than a century ago.
It may be assumed from ancient writings that the Greeks and Romans
made use of native gladiolus species for ornamentation, and it is certain
that there were species of the gladiolus, known as Corne Flags, in
Britain as early as 1597, when they were recognized as important
garden plants by Gerarde. But it was not until 226 years later that
the first important hybrid gladiolus was produced.
Interest in Europe was at first limited to the species native to
southern Europe, Asia, and Persia. They numbered but 15 and were
never very popular with gardeners. Early in the seventeenth century
the development of these species came to a standstill. It was more than
a century later, when new species first started coming in from southern
Africa, that renewed interest was gradually stimulated in the gladiolus.
FLOWERS 943
In the eighteenth century botanists and explorers became increas-
ingly aware of the new species of plants to be found around the Cape
region of Africa, but it was not until the close of that century, when
the Cape of Good Hope became subject to Great Britain, that large
importations to Europe were received, William Herbert, dean of
Manchester, seems to have been one of the first to recognize the value
of the Cape species of gladioli, for in 1820 he wrote:
I am persuaded that the African Gladioli will become great favorites with
florists, when their beauty in the open border, the facility of their culture, and the
endless variety which may be produced from seed by blending the several species
are fully known, nor will they be found to yield in beauty to the Tulip and
Ranunculus.
Dean Herbert, besides contributing valuable information to horti-
cultural literature, was also an enthusiastic cultivator of gladioli and
was regarded as an authority on Cape bulbs. He carried on consid-
erable hybridization with the species of gladioli and recorded in the
horticultural literature a large number of his successful crosses.
During Dean Herbert's time the first important hybrid appeared at
Colville's Nursery, Chelsea, England, in 1823. It was derived from
Gladiolus tristis L. var. concolor, with 6. cardinalis Curt, as the pollen
parent. This new variety was given the Latin name Gladiolus colvillei
Sweet and was known commonly as Colville's corn flag. It was de-
scribed as being tall and vigorous with flowers of bright scarlet with
lanceolate blotches of white on the three lower petals. There are to-
day several named varieties persisting in the trade that came directly
from this outstanding hybrid. In the United States they are generally
grown under glass in the East but will grow out of doors successfully
in the milder climates along the west coast.
Fifteen years later the second important hybrid, which was named
Gladiolus ramosus Paxt., was produced in France. It was first
flowered by M. Bifkogel in 1838. Records indicate that this hybrid
resulted from a cross between hybrids of G. cardinalis and G. oppositi-
florus Herb. It bore a tall flower spike with heavy broad leaves.
The flower was openly funnel-shaped and bright red with deep blotches
at the bases of the three lower segments. The fact that it bloomed
later than other varieties of its time made it important for at least the
next 20 years.
Until 1841 there was a mild yet increasing interest in gladioli, par-
ticularly among amateurs, but that year a variety was introduced that
caused the greatest stimulation ever evidenced in the history of gladi-
olus breeding. M. Beddinghaus, gardener to the Duke of Aremberg,
had been breeding gladioli for a number of years, securing for this
work as many species as were then available. Louis van Houtte, of
Ghent, Belgium, realizing the potentialities of one of M. Beddinghaus'
productions, immediately purchased the stock, and in 1841 Gladiolus
gandavensis Van Houtte was introduced to the world. Van Houtte
named this gladiolus after the city of Ghent and described it in glowing
terms as bearing majestic flowers, numbering 18 to 20, of the most
charming vermilion, the inferior petals adorned with chrome, ama-
ranth, and brown. For a long time there was considerable controversy
concerning the parentage of G. gandavensis. It is now accepted that
this new variety resulted from a cross between G. psittacinus Hook.
944 YEARBOOK, 1937
and G. oppositiflorus or between hybrids from these species. Napo-
leon III heard of this variety, which had "created a furor in the
gladiolus world", and some of the plants came into the possession of
Souchet, gardener to the Emperor at the court of Fontainebleau .
Souchet, using G. gandavensis as one of the parents, developed many
new hybrids, which in time were the talk of Europe.
In England Dean Herbert kept in close touch with new gladiolus
varieties and continued the pioneer work he had started, using new
species and varieties in his breeding work as they became available.
Representing the trade in England, James Kelway, the founder of the
Langport firm, was alert to the rapid development of the gladiolus and
secured hybrids from Souchet in France to develop them further and
make them available for sale in England.
Queen Victoria's visit to Fontainebleau in 1855 is reputed to have
stimulated a tremendous interest in the gladiolus, for she saw and
greatly admired the new varieties developed by Souchet and exhibited
by Napoleon III. By 1880 over 2,000 named varieties had been
developed that showed characters derived from Gladiolus gandavensis.
Victor Lemoine was greatly interested in the development of new
gladiolus varieties and the next race of hybrids of considerable im-
portance resulted from his work at Nancy, France, around 1880.
Crossing Gladiolus gandavensis with G. purpureo-auratus Hook., which
was introduced in 1872, he obtained a race called G. lemoinei Hort.
These varieties were characterized by their large flowers and the
prominent blotches in the throat of the florets.
Meanwhile Max Leichtlin, of Baden-Baden, Germany, crossed
Gladiolus gandavensis with G. saundersii Hook, f., which had been in-
troduced from the Cape in 1870, and G. leiehtlinii Baker was pro-
duced. This stock was ultimately purchased and imported by John
Lewis Childs, of Long Island, N. Y., and renamed G. childsii. W. Van
Fleet crossed a variety of G. childsii with G. cruentus Moore and se-
cured, ampng many others, his famous variety Princeps. The pur-
pureo-auratus-gandavensis hybrids developed by Lemoine were crossed
by him with G. saundersii and a new race called G. nanceianus Hort.
resulted, which was characterized by plants having remarkably large,
open flowers with contrasting color mottlings in the throats.
Gladiolus primulinus Baker has been the most recent introduction
to greatly influence the development of gladiolus varieties. This
species was found in the Rain Forest near Victoria Falls on the Zam-
bezi River in Africa. It was successfully introduced and flowered at
Kew Gardens, England, in 1890. Since then it has played an im-
portant role in modifying gladiolus flower form and color. French,
English, and American plant breeders have all taken part in develop-
ing new varieties with some of the characters of G. primulinus. The
most outstanding characters it transmits are a light and graceful
flower stem, a more or less pronounced hooding of the flowers, and a
subduing of brilliant hues to soft pleasing colors. In turn the progeny
from G. primulinus have been improved by increased flower size and
more vigor in the flower stem.
Noteworthy also are the ruffled gladioli, which have been developed
in the United States by A. E. Kunderd, at Goshen, Ind., starting about
1907. Later he also developed a strain having fringed and laciniated
FLOWERS 945
segments, which has created much interest. Foremost among the
Canadian pioneers in the development of the gladiolus was the late
IT. IT. Groff, of Simcoe, Ontario. About the end of the nineteenth
century he had developed a strain called Groff's hybrids, which were
considered noteworthy, particularly because of the wide range of color
they possessed.
At the present time there are many amateurs and professional and
commercial growers deeply interested in the breeding of new and
superior varieties of gladioli in the United States. The American
Gladiolus Society, organized in 1910, did a great deal to encourage the
production of new and finer varieties, as well as to straighten out
nomenclature. It publishes a monthly, the Gladiolus Review, in
wl lich registrations of new gladiolus varieties are included . This organi-
zation sponsors affiliated State and regional societies and conducts an
annual gladiolus show where new varieties are exhibited and evaluated.
Governmental agencies have also contributed to the development of
the gladiolus. Particularly noteworthy is a series of publications dur-
ing the last 20 years from the New York State College of Agriculture,
Cornell University, by A. C. Beal, A. C. Hottes, and A. M. S. Pridham
of that institution on the development of superior varieties of gladioli.
At Cornell University there is a test garden in which most of the
available species and varieties of gladiolus have been grown and
studied. Likewise, at the New York Botanical Gardens a collection
of gladiolus species is maintained.
Recently a technical paper has appeared written by Bamford (10),
of the Maryland Agricultural Experiment Station, who collected many
gladiolus species and varieties and made detailed chromosome counts.
His work greatly expands similar studies on the same subject by M.
Ernst-Schwarzenbach (1931) in France and by McLean (326) in the
United States. Such cytological studies are of great help to the genet-
icist in his attempts to classify material and breed superior varieties.
This brief discussion serves to direct attention to the great com-
plexity of the inheritance of modern gladiolus varieties. Original
species have been combined and hybrids have been crossed and
rccrossed until the resulting multiple hybrids possess characters derived
from many different species. Superior characters have been combined
and varieties have been selected covering a wide range of usefulness,
from the requirements of the florist who forces plants under green-
house conditions to those of the amateur flower lover who demands
a wide range of color and form for flowering through the summer.
How much more can be accomplished in the development of the
gladiolus is a matter of speculation. When it is realized, however,
that less than a score of the more than 150 known species have
been used to any extent in the development of over 2,500 varieties of
gladiolus in commerce at the present time, it seems probable that
present and future plant breeders can still draw from the remaining
species to give to the world even more desirable gladioli than we now
J Hemekocallis (Daylily)
The daylilies had not received much attention from breeders until
the last decade of the past century. Previous to this a few species
had been grown in Europe. They were first mentioned by Pena and
946 YEARBOOK, 1937
Lobel in 1570, when these authors described what is probably the
common Lemon daylily. A few years later Lobel described a second
species with single cinnabar-red flowers. These two were apparently
the only ones known in Europe for the next 200 years. Unfortunately
little is known of the situation in China and Japan before the nine-
teenth century.
In 1768 a third type was mentioned in Europe, but its exact origin
is unknown. It was regarded by some as being a minor variety of one
of the two older established types. About 1798 another new type
appeared, this time imported from the Orient into England. No new
ones were introduced until about 1934, when a semidwarf form was
brought in from Japan. In 1856 another semidwarf appeared, and
this was followed in 1860 to 1864 by double-flowered forms.
The first actual breeding of daylilies probably dates from about 1890.
Previous to this all new types that had appeared in Europe and the
United States were simply plant importations from the Orient. The
development of new types from seedlings was begun about 1890 by
George Yeld in England. His first introduction, named Apricot,
appeared in 1892. A more recent contributor is A. B. Stout, of the
New York Botanical Garden. He has attacked the breeding problem
from a scientific angle, and it is to him that we owe the greatest part
of the genetic information now available on this group of plants. The
breeding of new forms has increased so rapidly, chiefly as a result of his
research, that there arc now probably more than 300 different varieties.
The breeding of daylilies is handicapped by many obstacles. Among
these are self-sterility and cross-sterility, which inhibit seed setting,
the hybrid nature of the available types, and the comparatively slow
rate of increase after a desirable variety has been developed.
The types of sterility encountered may, according to Stout, be classi-
fied into four groups:
(1) There appears to be lack of affinity between certain species in
the relations of fertilization. Yet hybrids have been obtained from
many of the combinations between species.
(2) There is much abortion of pollen grains and egg cells in certain
hybrids, such as Hemerocallis flava L. X H. nana, and in triploids,
such as the Europa daylily. This condition greatly reduces the chance
that a plant will bear seeds, but there may be a few viable pollen grains,
in which case the plant may be used as a pollen parent.
(3) There is abortion of pistils in the older triploid double-flowered
forms, although some viable pollen is formed.
(4) In daylilies there are many types of incompatibility. Some
plants set seed only when self-pollinated, others when pollinated by
sister plants, and still others only when cross-pollinated by certain
other species. Studies have been made which show that in some cases
of sterility pollen tubes grow poorly in the style or fail to enter the
ovary. Some clones are completely self-sterile, others set a few seeds
when self-pollinated.
The wide variation in any group of daylily seedlings is rather strik-
ing. Even seedlings of the older, well-established clones are usually
very inferior to the parent type. This indicates, of course, that day-
lilies are probably heterozygous for a large number of genes. The
chances of securing improved types depend almost entirely on the
FLOWERS 947
number of seedlings grown. According to Stout, only 14 superior
seedlings were found out of a total of 15,000 grown. Others apparently
had some merit, since about 100 more were saved for use in selective
breeding.
The present information on daylilies indicates that many new types
can be developed by intercrossing the existing clones. Because of the
heterozygous nature of the material, lack. of genetic data, and general
self-sterility, a scientifically planned breeding attack is difficult.
About all that can be done at present is to grow large populations and
select the superior types either for introduction or further breeding.
It would be desirable to establish some self -fertile lines so that a genetic
analysis of some plant characters could be made.
The cytological investigations of daylilies have shown some interest-
ing results. The basic chromosome number of all the species appears
to bo 1 1 . The common European form of Ilemerocallisfulva L. , which
Stout calls Europa, has 33 chromosomes and is therefore a triploid.
According to Belling and Stout this species shows considerable irreg-
ularity in the formation of pollen colls, so that very few good pollen
grains or egg cells are formed. Further studies by Stout snowed that
triploidy was fairly common in daylilies and this may account for some
of the prevalent sterilitv.
The garden irises may be grouped in several classes, such as the
boarded, beardless, and" bulbous types. This discussion is limited
to the commonly cultivated tall bearded type. As is true of many
other ornamental plants, the early history of the iris is shrouded in
mystery. According to J. C. Wister, bearded irises are native to
central and southern Europe and Asia Minor, in a region extending
from the Alps through Italy, Hungary, Bulgaria, Palestine, and Iraq.
There are no records of when man first began to cultivate the wild
types, but it was probably very early, since the ancients attributed
various medicinal properties to the rootstocks.
Iris albicans Lange is the first species about the culture of which
there is definite knowledge. This iris probably originated in Arabia
and was carried all over southern Europe by the Mohammedans, who
planted it on the graves of their soldiers. There are no records as to
when this practice was begun, but by 750 A. D., when the Moham-
medans were driven out of Spain, the species albicans was already well
established there.
The first reference to the growing of the iris in European gardens was
in 1790. At this time about a dozen wild forms were listed in several
garden catalogs. The next 60 years saw a rapid increase in the popu-
larity of irises, and it was during this period that the first iris breeding
was begun. Prominent among the early workers were Lemoine,
Jacques, and Salter, who produced many new improved forms. Un-
fortunately there are no authentic records of what these three men did,
and any varieties they may have named have been lost. The first
authentic record of named iris seedlings was as recent as 1855. At this
time M. Dauvesse, a nurseryman of Orleans, France, offered a half
dozen or so new varieties.
Within a dozen years thereafter the growing of iris seedlings was
undertaken by many people. The most prominent of these were
948
YEARBOOK, 1937
Louis Van Houtte and Verdier of France, Krelage, Roozen, and
Van Leeuwen of the Netherlands, and Peter Barr of England.
Previous to 1890 it seems that most of the new seedlings were
derived from the two species Iris pallida Lam. and /. variegata L.
The results were limited by the potentialities of these two species.
Sir Michael Foster about 1880 began collecting iris species and
forms from all parts
of the world to use in
his breeding program.
The results of some of
his crosses were so
striking that other
breeders were stimu-
lated, and soon a num-
ber of new species com-
binations began to ap-
pear. It is likely that
errors of nomenclature
may have crept into
some of this early
work, and there may
be some doubt about
the alleged parentage
of some of the crosses.
Among the modem
iris breeders of Europe,
the late A. J. Bliss, of
England, is probably
the best known. He
was interested in
studying the relation-
ships of many of the
present varieties, but
he also developed some
very fine new ones.
He did not specialize
in one type of flower
but was interested in
a wide range of forms.
The history of iris
breeding in the United
States dates back to about 1905. At this time Bertrand H. Farr, of
Pennsylvania, introduced a collection of superior new varieties from the
English firm of Barr. Working with this material, he was able in 1 909
to introduce some excellent new seedlings. This work soon stimulated
widespread interest, and very shortly large numbers of amateur
growers were producing seedlings. In an article of this length it is
obviously impossible to mention all the American breeders.
One of the most careful and prolific workers is Grace Sturtevant,
of Massachusetts (fig. 18). She has continuously maintained a
collection of the very finest varieties to use as parent plants and has
developed over 40 new worth-while introductions. Among them
Figure 18. — Grace Sturtevant, one of the leading iris
breeders in the United States. Some of our finest iris
varieties owe their origin to her.
FLOWERS 949
Afterglow, B. Y. Morrison, Queen Caterina, Reverie, and Shekinah
are of exceptional merit.
Another American breeder who developed some excellent new
varieties was Edward B. Williamson, of Indiana. From about 1910
until his death in 1933 he introduced many new irises. One of the
best known came from crossing about 500 flowers of the variety
Amas with other varieties. Only one seed pod was formed in these
crosses, and one of the seeds in it produced the seedling later named
Lent A. Williamson.
J. C. Nicholls, Ithaca, N. Y., is credited with very careful work on
iris breeding. He rigidly selects the parents for each cross and keeps a
very careful set of records of all his work.
On the Pacific coast, the work of Sidney B. Mitchell and of E. O.
Essig is noteworthy. Mitchell has developed many excellent
new varieties and recently has devoted most of his time to develop-
ment of new yellow types. Essig began iris breeding as a hobby
and has carried on a series of careful experiments on seed germina-
tion under different conditions. He also has introduced several
excellent new seedlings. Other American breeders of note are
J. M. Shull, of Washington, D. C, and the Sass brothers, of
Omaha, Nebr.
The methods employed by some of the better iris breeders are
illustrative of the large amount of work necessary to produce really
superior types. The late Edward B. Williamson formulated a plan
to assure a higher degree of success with his crosses. From his
early experiences he knew that many crosses would not produce
seed, and the only way to discover which would was to attempt the
cross. He decided to use a mixture of pollen in all crosses, reasoning
that the prospect of getting some seed would be much better since
there was a chance that one or more of the pollens used would be
effective. The pollen was gathered from hundreds of flowers and
mixed in a receptacle. From 1925 until his death in 1933 he planted
each year from 70,000 to 100,000 seeds. He never introduced more
than 10 seedlings in any year. The percentage of worth-while
varieties is thus rather low.
The methods of J. C. Nicholls are in decided contrast to those of
Williamson. Accurate records of both parents are kept. Parents are
selected with care, and about 3,000 seeds are planted each year. It
is rarely the case that more than 1 iris worthy of varietal status is
found in 1,000 seedlings.
Unfortunately little or nothing is known concerning inheritance
in iris. Bliss made some preliminary observations on inheritance
of leaf pigmentations and coloring of the beard, but the evidence
is too meager as yet to warrant a genetic analysis of these
characters.
The very early iris breeders simply planted seed and hoped some-
thing good would turn up. At the present time the better breeders
choose both parents with care and control all crosses. This informa-
tion about parental stocks, however, has little actual value unless
the frequency of superior seedlings arising from each cross is known.
Since many of the crosses give only a few seeds or none, a summation
of data for the same cross from various breeders would certainly be
950
YEARBOOK, 1937
worth while. If such information were available a table of breeding
qualities of various varieties could be made that would be of some
value. Undoubtedly some of the more careful breeders have this
sort of information on their own work, but it has not been collected
and published .
According to the experience of some iris breeders, one of the serious
problems has been sterility. Some varieties are both cross-sterile
and self-sterile, others are cross-sterile and self-fertile, others cross-
fertile and self-sterile, and still others both cross-fertile and self-fertile.
In some cases there are differences of opinion concerning certain
varieties, which indicate cither an error in nomenclature or that the
same variety behaves differently in various localities. In general it
can be said that crosses between closely related types have the best
prospect of producing seed, with less and less success as the varieties
are more distantly related. Likewise, hybrids between closely related
types are most likely to be fertile.
Another difficulty is slow and sometimes poor seed germination.
To a geneticist attempting to work on the inheritance of some char-
acter this is a great obstacle. Whether or not it is due in some cases
to poor horticultural practice, it is one of the things that will have to
be overcome before much real genetic research can be accomplished.
Lily
To many people in the United States the word lily is closely asso-
ciated with thoughts of Easter, and they are familiar with only the
large-flowered, so-called Easter lily, Lilium longiflorum Thunb. This
lily is widely grown by florists, who force it for sale as potted plants
and also as cut flowers. Easter lilies are rarely grown in outdoor gardens
except in very mild climates where they are able to survive the winters
and are not exposed to late spring frosts.
One of the best known of the other lilies is the popular so-called
Tiger lily, Lilium tigrinum Ker. This old-fashioned favorite is a very
hardy species and has become widely distributed throughout most
parts of the country. Not long after it was introduced from
China it escaped from cultivation and is now found growing wild
in many sections.
Table 2. — Species of Lilium classified according to date described
and continent of origin
[Compiled from Stoker (49.',)]
Species originating in—
Total
When described
Species originating in-
When described
North
Amer-
ica
Europe
Asia
North
Amer-
ica
Europe
Asia
Total
1753
Number
1
3
1
0
7
Number
5
1
1
3
0
Number
i 1
3
5
0
0
7
8
13 I
1870-1900
1901-25
Number
5
4
1
Number
2
2
0
Number
11
13
5
1754-1800
IS)
1801-25...
1920-36 .
Total
1851-75....
22
14
49
w
1 Duplicate.
FLOWERS 951
Until very recently only a few lily enthusiasts were familiar with
the many beautiful garden forms now available. Most of these new
types are wild species from afar that have been introduced by plant
explorers. Asia has furnished nearly two-thirdsof these, as is shown
in table 2. Until quite recently the species introduced by plant
explorers more than met demands for new types. The prospect of
finding striking and distinct new forms in the wild is now rapidly
diminishing, for they do not readily escape the eye of the botanical
explorer. Since this is true, it seems that in the future hew and
superior lilies must come from the plant breeder rather than the
explorer.
As recently as 50 years ago only a dozen species of Lilium were
grown in England, and few sources of bulbs or seeds were available to
enthusiasts who wished to grow others. At the turn of the century
interest in lilies was waning, but was revived by the introduction of
the easily grown Lilium regale Wils. from China in 1904. Other new
forms from China followed, including L. sargentiae Wils. and L.
willmottiae Wils. The formation of a lily committee by the Royal
Horticultural Society and publication of its Lily Yearbook, beginning
with 1932, also stimulated interest in England. In the United
States the popularity of lilies has kept pace with the growing interest
in flowers in general, and the American Horticultural Society has
appointed a lily committee this year (1937). New hybrids and more
readily available stocks of lily species have also encouraged wider
use in gardens everywhere.
A uniform system of naming lilies is essential to an intelligent
discussion of lily breeding. Unfortunately for the general public only
a few species have well-recognized common names. The use of
botanical names is general even in popular accounts, and while these
may have a forbidding technical appearance, yet they are in most
instances the only generally accepted designations available. For
example, the popular Regal lily is known to all botanists and lily
enthusiasts as Lilium regale. Since most lily breeders become
interested in the relationships of the various forms, an outline of the
division of the genus Lilium into subgenera and sections has been
included in the appendix. In this appendix also is a list of lily hybrids,
including reports of species crosses from which no named hybrids
have been grown. Such a list should be helpful to the amateur
hybridizer in pointing out which crosses are readily made and which
combinations are difficult or not yet accomplished.
On this continent notable contributions to our array of garden
lilies have been made by the late David Griffiths (fig. 19), of the
Department, and by Isabella Preston, of the Dominion Experimental
Farm at Ottawa, Canada. Griffiths is best known for his work on
the propagation of lilies, but he developed and distributed a number
of fine Martagon hybrids {152), one of which is Star of Oregon.
Miss Preston has made great numbers of cross-pollinations with the
principal objective of developing hardier lilies for Canadian gardens.
Some of her named productions are George C. Creelman, Davmottiae,
and the more recent Grace Marshall, Lila McCann, Lilian Cummings,
and Phyllis Cox. Many amateurs are active in the United States
and in Canada, and some fine hybrids have resulted from their efforts.
952
YEARBOOK, 193 7
In England the Backhouse hybrids produced by Mrs. R. O. Back-
house of narcissus fame are perhaps the best known of the newer
lilies, but activity is widespread there as well as on the Continent of
Europe.
In the literature of lilies the notation of hybrids has been so casual
that Miss Preston felt it desirable to state: "In my notes the seed
parent is placed first" (410).
Other writers have departed from
this practice so commonly that it
is only by chance reference to one
or the other species as seed par-
ent or pollen parent that the
reader can tell which cross is dis-
cussed. It should also be point-
ed out that somercportedhybrids
are based on inferences as to what
the parents should have been to
produce the observed effects,
and, further, that some reported
hybrids may be merely asexual
offspring of the seed parent.
Natural hybrids are not common
in Lilium, at least in England,
according to Grove (155); but
Preston (410) reports two from
Canada. Lilium testaceum
Lindl., L. tlegans Thunb. (syn.
L. thunbergianum Schultes), and
L. umbellatum Hort. are all re-
cognized as hybridsof longstand-
ing, in the origin of which man
may have played no part.
Several examples of suppose-
dly hybrid seedlings that appear-
ed to be identical with the mater-
nal parent were recorded by Parkman (402) in 1878. He found that
Lilium superbum L., emasculated and pollinated by L. auratum Lindl.,
L. tignnum Ker, L. chalcedonicum L., or various other species, pro-
duced seedlings that were always' pure L. superbum. When these
seedlings were pollinated with other species, the second generation was
still unchanged L. superbum. Similar results followed the applica-
tion of pollen of other species to L. umbellatum Hort., and the Easter
lily, L. longiflorum. Griffiths has commented that maternal inherit-
ance is remarkably prevalent in lilies, and (154) that L. regale yields
better results when used as a pollen parent because of this tendency.
Stout (497) concedes that seedlings of maternal character in Lilium
may result from wide crosses, without fertilization and production of
true seeds. Preston (409) has found that seedlings of L. regale polli-
nated with L. speeiosum Thunb. var. rubrum Hort. or with L. longi-
florum are strictly maternal in character, and that the progeny of a
L. regale X longiflorum cross remained pure L. regale in the second
generation.
Figure 19.— The late David Griffiths (1867-
1935), who did outstanding breeding work
on lilies and narcissus while a member of the
United States Department of Agriculture.
He is also well known for his work on
methods of propagation and production of
tulips and hyacinths.
FLOWERS 953
Further reports of similar nature could be cited. Such results
might be attributed to late or incomplete emasculation or to ineffective
protection against pollen of the maternal species, but such explana-
tions cannot be pressed in the face of reports from careful hybridizers.
Some form of parthenogenesis must be assumed in the production of
such pseudohybrids, as is suggested by Hall and his coworkers (191):
The possibility has to be borne in mind that crossing certain lilies may not
result in producing true seed, i. e., by sexual union of the pollen cell with ovule.
Excitation due to the foreign pollen may induce the formation from the ovule
of a "seed" which is really a bud of the mother plant into which the pollen has
not entered.
It has already been mentioned that many hybrid lily types of the
past century in particular were noted alike for their beauty and their
quick disappearance. Striking examples are Parkman's Lilium specio-
sum X auratum (1869) and the reciprocal cross produced by Hovey
about 1880, each of which persisted scarcely long enough to be admired
and photographed. Most of Burbank's productions are now only
memories.
Premature passing of some hybrid types is clearly due to misfor-
tunes of culture before the stock was developed to commercial quan-
tity. It was Griffiths' aim to stress the need for rapid, efficient vege-
tative propagation to insure establishment of a desirable hybrid as
soon as possible, and he devoted much of his energy to improving
methods of propagation with this in mind. Some desirable hybrids
are inherently slow or difficult to propagate (151) and may be lost
through the producer's haste to market his creation. Other hybrids,
of course, are genetically weak and incapable of long survival, an
extreme example of which is the albino seedling.
One of the least excusable reasons for loss of a hybrid is failure to
recognize the necessity of vegetative propagation if the stock is to be
kept true to type. Very frequently seed of a promising hybrid lily
is offered for sale and the seedlings produced are sometimes called by
the name of the parent plant. This is obviously a wrong procedure,
since it would be very unusual for a first-generation hybrid to breed
true. Griffiths (151) also calls attention to the fact that there has been
a tendency to treat all the hybrids coming from a cross as a variety
rather than selecting an outstanding one for vegetative increase as a
clonal variety. Such practices have undoubtedly added to the pres-
ent confusion regarding many named lily hybrids. They are con-
trary to the fundamental principles of genetics, and lily breeders will
do well to discard them.
Another important reason for decline or loss of lily hybrid varieties
is the presence of virus diseases such as mosaic (155). The viruses are
carried in the living cells of the plant and are spread from plant to
plant by aphids. When a diseased lily is propagated by division, by
stem bulblets, or by scaling, each new plant produced will have the
disease. No method is known by which such diseased lilies can be
made healthy. If a new hybrid is attacked, it may as well be dis-
carded. Fortunately these diseases are not commonly transmitted
through the seed. Accordingly seedling lilies are usually free from
virus diseases to begin with and should be grown at a safe distance
from affected parent plants and other diseased lilies.
138904°— 37- 61 ++
954 YEARBOOK, 1937
It is generally known that some species of Lilium do not readily set
seed when pollinated with their own pollen. As early as 1890, Focke
demonstrated that Lilium buibiferum L. could be divided into certain
groups which would set seed only when pollen was used from a mem-
ber of another group (497). There are many references to the failure
of the Madonna lily (L. candidum L.) and the Tiger lily (L. tigrinum)
to develop seeds. Preston states that L. testaceum and L. hansoni
LeichtL, as well as L. tigrinum, arc self-sterile at Ottawa, Canada.
She later (410, 411) reports a fertile strain of L. tigrinum that she has
named "var. diploid." Griffiths cites L. regale and L. longijlorum as
species that set seed only when different plants are interpollinated.
Amsler (4) reported that L. brownii Poit. and L. parryi S. Wats, set
no seed when selfecl, but did when pollinated with other strains of the
same species. Stout (497) and others who have studied self-incom-
patibility in Lilium made systematic trials with proper attention to
emasculation, bagging, and hand pollination, and showed that failure
of individual plants to set seed on selfing is widespread in lilies. L.
tigrinum and its varieties flore-pleno, splendens, and fortunei are trip-
loids (191), having 36 chromosomes, and rarely mature functional sex
cells. The "variety diploid", however, has the normal diploid num-
ber of 24 chromosomes and is self-fertile (497). In other species the
failure to set seed is not due to inability to develop functional gametes,
as is shown by the successful results of interpollinating different lines
within a species. Even the triploid L. tigrinum will sometimes set seed
with the pollen of L. leichtlini var. maximowiczi (Kegel) Baker.
Stout (497) mentions occasional instances of failure of lilies to form
functional pistils or stamens. He also found poorly formed, nonfunc-
tional pollen in the hybrid L. testaceum, which he explained as caused
by hybridity and a like condition caused by triploidy in L. tigrinum,
but he holds that incompatibility is the most important reason for
failure to set seed in Lilium. In the species L. henryi Baker, L. spe-
ciosum Thunb., L. superbum, L. elegans Thunb., L. bulbijerum subsp.
croceum (Chaix) Baker, L. dauricum Ker, L. philadelphicum L., L.
auratum Lindl., L. humboldtii Eoezl and LeichtL, L. kelloggii Purdy,
L. willmottiae, L. roezli Regel, L. longijlorum, he found self-sterility to
be the rule but some few individuals set a little seed with their own
pollen. Among 59 plants of the common wild lily, L. canadense L., 4
fully self-fertile individuals were found, 6 partially self-fertile and 49
wholly self-sterile. Interpollinations of self-sterile plants were success-
ful in nearly all cases. Over 100 plants of L. hansoni studied were
fully self- and cross-sterile and may represent a single clone. This
strain was, however, reciprocally fertile with a new strain of L.
hansoni received from Manchuria. Stout found no fully self -fertile
individuals in L. candidum, and cross-fertility was rare and partial
until a new stock of unknown source was encountered. Species in
which Stout found no self-fertile individuals are L. hansoni, L. can-
didum, L. tigrinum (excluding the "variety diploid"), L. parryi, L.
chalcedonicum L., L. brownii, L. grayi S. Wats., L. sutchuenense
Franch., and L. maximowiczii Regel (= L. leichtlini var. maximowiczii).
Now that the pitfalls of the past are better understood, lily breeding
is undoubtedly on a surer basis and prospects are brighter than ever
before. The importance of vegetative propagation of hybrids is
FLOWERS 955
becoming recognized, and the methods of vegetative reproduction
have been improved. All hybrids start as seedlings and are, there-
fore; usually free at first from virus diseases, since, as pointed out
earher, these diseases are not commonly seed-borne. This point has
become widely appreciated, and efforts are being made to grow as
many lilies as possible from seed. When mosaic-free stocks of garden
lilies are more generally available, the prospects of increasing a hybrid
clone to commercial proportions before it becomes affected will be
greatly enhanced.
Some of the possibilities of hybrid combinations may be seen from
the tabulation of reported hybrids in the appendix. Crosses are in
general more successful within one section of the genus, but a number
of successful combinations of Archelirion with Martagon and of
Leucolirion with Martagon (see the appendix) are on record. Com-
binations not yet accomplished may succeed for the persistent breeder.
Cytology reveals no discouraging differences in chromosome numbers,
except in the case of the triploid Lilium tigrinum.
Some of the specific objectives of hybridizers are extension of the
flowering season (155), extension of the color range in reliable garden
forms {151, 155, 410), development of garden types even hardier than
Lilium regale (410), and incorporation of superior vigor and adapta-
bility in difficult garden subjects, such as L. leichtlinii Hook. f. (155),
L. humboldtii (153), and others (151). Griffiths suggests L. henryi
Baker as a promising parent carrying vigor and apparent tolerance
to diseases.
Unfortunately, little is known concerning inheritance in lilies. Some
of the species that are self-fertile do not give uniform seedlings, which
indicates that they themselves are hybrids. This situation is to be
expected because of the widespread self-sterility existing in the genus
which makes cross-pollination necessary for seed setting.
Nasturtium
The native home of the nasturtiums (Tropaeolum spp.) seems to be
the western coast of South America. They were found there by the
early Spanish explorers and introduced by them to Europe from Peru.
This probably happened sometime in the latter part of the sixteenth
century. The two species that found favor in Spain were T. minus
L. and T. majus L. From Spain they soon spread over most of
Europe. In England they were known as "Indian Cresses", the
name Indian being used because they came from the Spanish colonies
in South America, which at that time were described as the Indies.
At first the smaller-flowered T. minus was the most widely grown, but on
the introduction of varieties of the larger-flowered T. majus, the small
species was soon neglected. At the present time both types are found
growing wild in many sections along the west coast of South America.
The two species cross very readily, and many of the so-called Tom
Thumb varieties are supposed to have originated in this manner.
The range of colors and color patterns in the modern nasturtium is
one of the widest in the flower kingdom. In addition, some varieties
are known to bear flowers of various shades on the same plant. The
number of varieties listed today is very large, practically all having
been developed by professional and amateur efforts.
956 YEARBOOK, 1937
Not much is known as to the inheritance of flower color. Ras-
muson {427) has done some work and reports dark yellow as dominant
to light yellow, and presence of red to its absence. He also crossed
varieties bearing variegated flowers with some nonvariegated flower
types. From these crosses he was able to determine that variegation
was dominant. In the same investigations it was shown that the
dark green color of the leaf was determined by two genes, green being
dominant to yellowish green, and both to variegated.
In habit of growth the nasturtium may be divided roughly into
three types — the tall or climbing, the bush, and the dwarf bush. When
a cross is made between a pure tall and a bush, all the hybrids are tall,
and in the next generation there is a ratio of 3 tall to 1 bush. This,
of course, shows that climbing is dominant and controlled by a single
gene.
Recently considerable interest has been aroused by the introduction
of a double form which was named Golden Gleam (fig. 20). The
origin of this variety is something of a mystery. It was found about
10 years ago by J. C. Bodger in a flower garden near El Monte, Calif.
According to the owner, the seed had been brought into California
from Mexico, where it had been introduced from Spain. A search for
the type in Mexico, especially in the locality where it was reported,
was unsuccessful.
The seed from the California plant was sown the next year and all
seedlings proved to be doubles and true also for color. Within a few
years the seed was increased to considerable quantities and the new
variety introduced. Since other double-flowering plants of the same
type were not found, it seems that Golden Gleam probably arose as a
mutation from a single-flowered variety. There have been other
double nasturtiums, however, one being known as early as 1730, when
it was described and figured in colors in the Catalogus Plantarum.
The horticultural flore-pleno type mentioned in Bailey's Cyclopedia is
probably the same thing. This type, which is still grown to some
extent in Europe, differs considerably from Golden Gleam. It is
supposed to be entirely double, without production of pollen. Golden
Gleam, on the other hand, has anthers and a pistil and sets seed.
Shortly after the discovery of Golden Gleam, cross-pollinations were
made to develop other colors. This work was undertaken by Bodger
and Burpee. As a result, several mixtures of colors and a scarlet
double form appeared on the market a few years ago.
The inheritance of doubleness in nasturtiums has recently been
worked out by Eyster and Burpee {125). According to these workers,
singleness is a simple dominant to doubleness. When a pure single
variety is crossed with a double, all the hybrids are single. In the
second hybrid generation from such a cross, 78 plants were single and
27 double. This is very nearly a perfect 3:1 ratio. Since it is such
a simple situation, we may expect to have all colors represented in the
double type in a very few years.
A second double nasturtium has also appeared quite recently. It
differs very markedly from both the Golden Gleam type and the earlier
double reported from Europe. In the single flower there are five petals
while, according to Eyster and Burpee, Golden Gleam varies from an
occasional 5-petaled to a 15-petaled flower. The mean petal number
FLOWERS
957
Figure 20. — The double-flowered nasturtium Golden Gleam. This variety was -found
growing in a garden at El Monte, Calif. It was reputed to have come from Mexico,
but a diligent search in that country failed to locate any plants or information regarding
it. (Courtesy of Bodger Seeds, Ltd.)
958 YEARBOOK, 1937
seems to be slightly under 10. The new double type, which is called
superdouble, has from 40 to 50 petals, no pistil, and several modified
stamens. It does form some good pollen, so it may be regarded as
a staminate flower.
The origin of this new extreme double seems to have been spon-
taneous. It was first noticed in a greenhouse of several thousand
double-flowered plants. Since it lacked pistils it could not set seed
and had to be propagated by cuttings. The presence of some pollen,
however, made it possible to use it as a male parent in crosses with
singles and with doubles of the Golden Gleam type. When it was
crossed with pure single plants, about half the hybrids were singles
and about half superdoubles. Likewise, when crossed with Golden
Gleam a 1:1 ratio of doubles and superdoubles was secured. From
these results it is apparent that the new superdoubles are all hetero-
zygous (impure) for the new character, which is obviously a simple
dominant to both singleness and doubleness. If they had been
homozygous (pure),, all the hybrids would have been superdoubles in
both instances. From this it can be seen that the production of new
colors in superdoubles involves an actual hybridizing process.
They can be made only by crossing a superdouble with a single or
double of some new color. If the gene for superdoubleness is not in
the same chromosome as the gene or genes for color, it will be a com-
paratively simple matter to provide the extreme double in the full
color range of the ordinary single nasturtium. If the color gene and
the superdouble gene are in the same chromosome the desired result
can still be secured, but it will require the growing of a much larger
population in order to get the new combination. Unfortunately,
adequate linkage data are not available for nasturtiums.
Rose
The rose is one of the most widely grown and admired of all the
flowers. There now exist several thousand named varieties in a wide
range of color and form, including types for almost all conceivable
conditions of growth. The greenhmise forcing roses, hardy outdoor
varieties, climbers, bush, and polyanthas are some of the many types
now grown. This wide variation and development has largely
occurred in comparatively recent years.
The rose is one of the oldest of our cultivated flowers. It first
appears in the early art of long-destroyed civilizations and is fre-
quently mentioned in the Bible and in Greek mythology. It was
undoubtedly the favorite flower of many of the rulers of Greece and
Rome and was used as a symbol on their banners and shields. This
early popularity continued on down through the Middle Ages, and
roses were the symbols for the great houses of York and Lancaster in
the so-called Wars of the Roses in England.
The genus Rosa is a large one with several races, widely distributed,
and native mostly in the North Temperate Zone. However, a few
species are found near the Equator and even above the Arctic Circle.
Many of the finest are native to eastern Asia, but they have not been
so highly developed there as in the western part, especially about the
eastern end of the Mediterranean Sea.
FLOWERS 959
In Europe during the sixteenth century only a few rose varieties
were cultivated and at least half were singles. Two hundred years
later there had been only a slight increase in the available varieties.
In England at this time there were 21 species in cultivation, and about
30 double varieties. Importations were very rapid after 1789. In
this year the Crimson Chinese Monthly, Rosa chinensis var. semper-
flore,ns Koehne, was introduced. Three years later the Macartney,
R. bracteata Wendl., made its first appearance, and in 1796 R. rugosa
Thunb. This was followed by R. multiflora var. cornea Thory, the
first rambler rose, in 1804; R. banksiae R. Br., in 1807; R. chinensis
var. odoratissima Lindl., the tea-scented rose, in 1809; and the Fairy
rose, R. chinensis var. minima Rehd., and Eduard, a Bourbon type,
in 1810. About 1816 a rambler rose, Seven Sisters, R. multiflora var.
plaiyphylla Thory, appeared. This was followed in 1823 by the
microphylla or small-leaved type, R. roxbwghii Tratt., from China.
While only meager records are available, it seems very probable that
these new species were used in crosses with some of the native species
such as R. gallica L., R. rubiginosa L., and the so-called Ayrshire roses.
By 1829 R. Desportes briefly described 2,562 species or varieties then
under cultivation in France. This enormous increase in so short a
period is very interesting. It is extremely improbable that it was in
anyway caused by a sudden tendency to production of sports or muta-
tions. > Other factors are more likely to have been responsible, among
which importation from other continents and the growing and selec-
tion of seedlings were probably two of the most important.
Cultivated roses were probably brought into the United States by
the earliest colonists. Very little is known concerning them during
these early days, and it was not until after the Revolutionary War
that any account is found of the naming of a new variety. This rose,
called Mary Washington, may very well be the first truly American
production. Shortly following this the Champney or Noisette roses
wore developed, and soon after, in 1840, Feast Bros., of Baltimore,
introduced hardy climbers having our native Rosa setigera Michx. as
one parent.
At the beginning of this century, most of the rose varieties grown
in the United. States had originated, m Europe. These importations
Avero very frequently disappointing in their behavior, and it was soon
realized that varieties should be developed under local environmental
conditions. This situation stimulated the efforts of American rose
breeders, and today there are hundreds actively engaged in this
fascinating work. In an article of this length it is obviously impossible
to cover all the contributions of these workers.
One of the earlier pioneers in the breeding of modern roses was the
late E. G. Hill, of Richmond, Ind. His first activity with roses began
in 1851 when he was employed in the nursery of T. C. Maxwell &
Bros, at Geneva, N. Y., where he became familiar with the very best
varieties then available. In 1 865 the Hill family moved to Richmond,
Ind., and in 1881 father and son launched the well-known firm of
E. G. Hill. About 1891 Hill began importing the newer hybrid teas
to test for cut-flower production under American conditions, and dur-
ing this last decade of the past century he undertook his own breeding
work. It was not until 1904 that two roses resulted which he believed
960 YEARBOOK, 193 7
were superior. These were General MacArthur and Mrs. Theodore
Roosevelt. In 1905 Richmond was selected from a large group of
red seedlings. These popular varieties were followed by many others.
Another American breeder who introduced many well-known vari-
eties is John Cook, of Baltimore. His first successful hybrid, Souvenir
of Wootton, was introduced in 1888. Other well-known varieties
developed by him are My Maryland, Radiance, Panama, and Francis
Scott Key.
Alexander W. Montgomery, Jr., of Hadley, Mass., is another who
has contributed valuable new varieties. Two of his introductions,
Hadley and Mrs. Charles Russell, are still very popular. The
Dorners, in La Fayette, Ind., have also produced several valuable
roses. Probably the best known of these is the widely grown Hoosier
Beauty.
The methods used by most of the amateur and professional rose
breeders are probably very similar. In general, some ideal typo is
determined upon and the breeder attempts to secure it by crossing
two varieties, each possessing some of the desirable characters. In
many instances, the eventual result is far different from the prede-
termined ideal, in fact, may even surpass it. In general, only a few
really successful new roses occur in a population of several thousand
seedlings. As an illustration of the odds against securing a really
desirable new seedling when varieties are crossed, the following is
quoted from an article by Hill {206) in the American Rose Annual
for 1917:
From the 1914 crosses there wore germinated over 2,500 seeds. Each little
plant was given special culture, being planted in a bench where it received the
same care as that required by the most important forcing varieties. In 1915 the
first weeding out of the seedlings occurred, and by 1916 the 2,500 seedlings had
been reduced to about 800. These were tested in blocks of five, receiving the
most rigid attention and critical scrutiny.
By the opening of 1917, the seedlings have been reduced to some fifteen sorts
which Mr. Hill considers worth while going farther with. Of these fifteen several
have been selected, named aud registered, and propagation is proceeding with the
idea of later dissemination.
From this group of 15 came: (1) Columbia, resulting from the
cross Ophelia X Mrs. Shawyer; (2) Double Ophelia, from a cross
between Ophelia and an unnamed seedling variety; (3) Rose Premier,
from a cross between Ophelia and Mrs. Charles Russell; and (4) Mary
Hill, from a cross between Ophelia and Sunburst.
Again quoting:
Others of the fifteen sorts are full of promise and will be reported upon later.
It may be observed that all of these roses are selected primarily from the forcing
or commercial cut-flower standpoint, but it is by no means improbable that several
of them may also prove as fine for outdoor use as General MacArthur.
A careful study of these results is very interesting. Suppose all
15 surviving seedlings are finally selected as worth while. The ratio
of the total seedlings to the number of good ones is then 2,500:15,
or about 1 desirable in 166. It is very probable that the ratio is often
considerably greater than this, in some instances reaching odds of
over 1,000 to 1.
The very wide variability exhibited by a large group of rose seedlings
has been a constant puzzle to many rose breeders. As early as 1889
FLOWERS
961
Lord Penzance, a . prominent English, rose breeder, published the
following statement: "Roses of the first order are, after all, very rare
in a sowing of seed, and their production is a veritable lottery, in which
chance plays the principal part."
Until fairly recent years, most rose breeders did not even keep a
record of parent varieties used in a cross. The lack of this informa-
tion has been deplored by many observers, but it is doubtful whether
such data would have the value apparently attached to it. For
instance, the parentage of the widely-grown old favorite, Caroline
Testout, is well-known, but it is very doubtful whether any breeder
could repeat the cross and secure another Caroline Testout. It is
not meant that such a result is impossible, but it is improbable. It
might occur if a very large number of hybrid seedlings were grown.
There is, however, a possible value in knowing the parentage of rose
varieties. It is very probable that we should find certain varieties
more apt to produce successful offspring than others. Such informa-
tion might be helpful in planning cross-pollinations.
The extremely mixed heredity of rose varieties makes planned
breeding very difficult. Since propagation is easily accomplished by
budding and grafting, this heterozygous condition is not a handicap
to the rapid increase of any variety.
Tabt.b 3. — Roses developed by Walter Van Fleet
Year
.1895
1895
1895
1895
1900
1895
1900
1902
1903
1898
1900
1904
1902
1900
1905
1907
1899
1908
1902
1902
1902
1918
1921
1923
1925
1925
1920
1926
1927
Variety
Typo >
May Queen
Ruby Queen
Clara Barton
Alba rubrifolia
Magnafrano
Pearl Queen
New Century
Philadelphia ...
Beauty of Roscmawr
Northern Light.
Sir Thomas Lipton- -
Charles Wagner
American Pillar
Birdie Blyc
Rugosa inagnifiea.-. .
Garnet Climber
Dr. W. Van Fleet... .
Silver Moon
Mary Lovett
Bess Lovett
Alida Lovett
Aunt Harriet-
Mary Wallace-- .-
Heart ot Gold
Sarah Van Fleet.-. .
Dr. E. M.Mills--.
Breeze Hill
Glenn Dale
Ruskin
H. W.
ir. w.
IT.T.Poly.
ir. w.
H. T.
n . w.
H. K.
H. M.
Bour.
H. W.
H. R.
II. P.
H. W.
H. M.
H. R.
H. W.
H. W.
II. W.
H. W.
IT. W.
II. W.
II. W.
II. W.
II. W.
H. R.
H. R.
H. W.
II. W.
H. R.
Parentage
Rosa viichuraiana X Mrs. do Graw.
Queen's Scarlet X R. wkhuraiana.
Clothilde Soupert X American Beauty.
R. wkhuraiana X Coquette do Lyon.
Magna Charta X Salrano.
R. wkhuraiana X Mrs. de Graw.
R. rugosa alba X Cloth ilde Soupert.
Crimson Rambler X Victor Hugo.
R. rugosa alba X Clothilde Soupert.
Jean Liabaud X Victor Hugo.
OK. wkhuraiana X R- setigera) X a red hybrid perpet-
ual.
Helene. X Bon Silene.
R. rugosa X Ard's Rover.
R. wkhuraiana X Lucullus.
(R. wkhuraiana X Safrano) X Souv. do Pres. Carnot.
(R. wkhuraiana X Devoniensis) X R. laevigata.
R. wkhuraiana X Kaiserin Augusta Victoria.
R. u-khuraiana X Souv. do Pres. Carnot.
Appolino X R. wkhuraiana.
R. wkhuraiana X hybrid tea.
(R. wkhuraiana X R. setigera) X R. moyesi.
R. rugosa X a hybrid tea, possibly My Maryland.
R. wkhuraiana X Beaute de Lyon.
R. wkhuraiana X Isabella Sprunt.
R. rugosa, Souv. de Pierre Lepcrdrioux X Victor Hugo.
1 Abbreviations have been used to designate the class to which the rose belongs:
H. W.=Hybrid wiehuraiana. H. M. = Hybrid multiflora.
II. R.=Hybrid rugosa.
II. T.=Hybridtea.
H. T.Poly=Baby rambler with hybrid tea characteristics.
H. P. = Hybrid perpetual.
Bour.=Bourbon.
While American rose breeders were not at first so active as Euro-
peans in producing hybrid teas, they have accomplished much in
developing hardy outdoor roses. One of the leaders in this work was
962
YEARBOOK, 193\
the late W. Van Fleet (fig. 21), who continued his rose-breeding
activities after he became a member of the Department of Agriculture.
He was an industrious worker, making many thousands of crosses
and keeping accurate records of his work. His objective was to pro-
duce continuous blooming roses for common dooryard culture under
the diverse climatic conditions of this country. In order to develop
such types he utilized all avail-
able vigorous species of pleasing
aspect, as well as strong-growing
garden forms, crossing them with
highly developed florists' varie-
ties. In this manner he hoped to
secure plants that would combine
the really desirable characters of
the parents. Two varieties devel-
oped by him were introduced
posthumously.
The complete list of Dr. Van
Fleet's varieties is given in table
:5, where they are arranged in the
order of their introduction. It
is interesting to note how few spe-
cies entered into the formation of
these varieties. Tlurteen of the
nineteen had Rosa wichuraiana
Crepin as one parent; three had
R. rugosa, two R. setigera, one R.
multijlora Thunb., and one R.
moyesiHcmsl. and Wilson. Some
of these introductions have
gained widespread recognition
and are widely grown.
Another breeder of hardy roses
is N. E. Hansen, of the South
Dakota Agricultural Experiment
Station at Brookings. He has
been working for some time to develop roses to withstand the severe
winters of that section. His first introduction was the variety
Tetonkaha, which appeared in 1912. In 1926 a second variety,
Tegala, was released, and in 1927, 13 others were introduced. All
these varieties have proved hardy at the Brookings station and have
been distributed in the Northwest prairie region.
The great diversity of form and habit in any group of rose, hybrids
is easily understood. To the geneticist it is the naturally expected
outcome when two highly heterozygous plants are cross-pollinated.
While the records of early hybridization in roses are none too authen-
tic, they do at least show that the ancestry of our modern varieties
is very complex. Thus the hybrid teas probably originated from a
cross between a hybrid perpetual and a tea rose. The teas are sup-
posed to have come from Rosa odorata Sweet. The hybrid perpet-
uals have a very complex ancestry. As far as can be determined,
the earliest progenitor was a damask rose called The Four Seasons.
Figure. 21. — The late Walter Van Fleet
(1857-1922), of the United States Depart-
ment of Agriculture, who did outstanding
work on breeding hardy outdoor roses. He
set as his goal the development of hardy
dooryard roses that would bloom continu-
ously from early spring until frost.
FLOWERS 963
It was being grown commercially in 1790 and was probably crossed
extensively with the French and Provence roses to give rise to the
damask perpetual. It seems that these were then crossed with
China roses, from which came the hybrid China types. According
to the records of this period all roses in this last group were apparently
sterile, but in 1830 a M. Guerin produced a hybrid named Malton,
which proved to be fertile. A second fertile hybrid called Athalin
was produced the same year by Jacques, gardener to the King, at
Neuilly. It is very likely the damask parent of each was a descendant
from the variety The Four Seasons. A few years later the variety
Athalin was crossed with Rose du Roi, a damask perpetual. Some
of these crosses were called hybrid damasks and were the direct fore-
runners of the hybrid perpetuals. In 1837, M. Laffay, a florist
located at Bellevue, near Paris, introduced Prince Albert and Princess
Helene, two new varieties. They were of the hybrid-perpetual type,
and M. Laffay is usually credited as the originator of this group. He
later produced other varieties, among which was La Reine. In 1844,
groups of hybrid Chinas, bourbon perpetuals, hybrid damask perpet-
uals, hybrid Gallicas, and moss roses were all combined to form the
hybrid perpetual group.
The hybrid teas, then, have a very diverse ancestry. This com-
plexity has been greatly multiplied by crosses among themselves, so
that our modern hybrid-tea varieties are undoubtedly a conglomera-
tion of many ancestral characters. Is it any wonder that even in a
group of thousands of hybrids from seed, no two are exactly alike?
The sudden spontaneous appearance of so-called sports in roses is
a well-known phenomenon. The frequency with which, they appear is
not known, although some varieties are supposed to produce more
than others. This, however, is probably based on the limited numbers
considered worthy of introduction rather than on the total actually
produced. There is little information about such sudden changes in
parts of the plant other than flowers. In many instances the sport
involves only a slight change in flower color, although very sharp
breaks, such as from red to white, are also known.
These mutations in the hereditary material in the cells may occur
at different stages of development and in different parts of the plant.
When, for instance, a red rose produces a branch bearing white flowers,
doubtless a change has occurred in the petal cells that carry the
color pigments. The change may have occurred in the bud that
produced the side branch, or it may have occurred at any time during
the growth of the shoot and flower bud. Sometimes the change in
hereditary material comes after the flower bud is almost fully de-
veloped. In such instances we may have bicolored flowers, each
pigment being restricted to a very definite sector.
It may sometimes happen that a particular bud taken from a
mutated branch fails to produce the new flower type. Such a situation
is called a reversion by rose breeders, but it probably indicates that
the mutation occurred after this bud had been formed.
No one as yet has been able to induce a sport in roses or explain the
forces that bring about the change under natural conditions. Some
of the future research on roses will undoubtedly be concerned with
such matters. It is possible that exposure of buds to X-rays, radium,
964 YEARBOOK, 193 7
heat, or some chemical might induce radical changes. Until such time
one must depend on the chance occurrence of mutations. Unfor-
tunately the erroneous idea has become current that special credit is
due the introducer of a new rose sport. Actually the rose breeder has
no control whatever over its appearance. lie is simply fortunate in
having the mutation occur in one of his plants. Such" introductions
should not be classed with actual breeding work where planned
cross-pollinations are made and thousands of seedlings grown. Even
in the latter case, our present methods are very little advanced over
what they were 45 years ago, when Lord Penzance called rose breeding
a lottery.
The contributions of science to rose breeding have been concerned
chiefly with pollen studies, studies of the chromosomes of the various
species, and methods of hastening seed germination. The classifica-
tion of the genus Rosa into species has been a verv difficult problem.
Various workers have from time to time revised the classification,
and there has not been any general agreement among them. This
confusion is probably caused by the lack of agreement on what
constitutes a species, as well as by the undoubted heterogeneous nature
of roses. In early days, as well as now, natural crosses between wild
roses probably occurred, giving rise to new intermediate forms. When
rose growing became so popular, amateurs began making cross-
pollinations between all available types, thus further complicating
the situation.
At the present time most rose varieties and so-called species are
actually mixtures of many types. Classification as botanical species
is practically impossible. Undoubtedly many of our present so-called
species are simply hybrids, as is indicated by the degrees of partial
sterility found.
An interesting study of the pollen of several wild species and some
species hybrids was made by Erlanson {120). Her method consisted
in staining the pollen and counting the percentage of poor, shriveled
grains. She found that poor pollen exists in all our native American
rose species. It averaged about 20 percent infertile in all except
Rosa aeicvlaris Lindl. and R. palustris Marsh., where it was about
10 percent. Even relatively fertile individual plants had as much
as 25 percent infertile pollen. In hybrids the percentage of poor
pollen was usually very much greater than in the wild species, and
the conclusion was reached that any wild rose plant with over 70
percent of infertile pollen and setting little or no fruit was probably
a first-generation hybrid.
Observations of the chromosomes of roses have also thrown some
light on the species problem. Eose species have been found with 14,
21, 28, 35, 42, 49, and 56 chromosomes in the body cells. These
numbers increase each time by 7 and are called a polyploid series.
According to Hurst there are distinctly different seven-chromosome
groups. He assumes at least five such groups, which he designates
as A, B, C, D, E. Different combinations of these five chromosome
sets would certainly explain much of the wide variability in the genus.
One of the greatest handicaps faced by rose breeders is* the matter of
irregular seed germination. Seed from some species sprouts readily,
while that from others may not start growth for several years. In
FLOWERS 965
1926 William Crocker, of the Boyce Thompson Institute at Yonkers,
N. Y., published results of his studies on after-ripening and germina-
tion of rose seeds. The seeds were stored at various temperatures in
moist granulated peat. The best temperature for both species and
hybrids was found to be 41° F. In some cases the acid in the peat
injured the rootlets of some roses, but this can be remedied by neutral-
izing the peat with a little lime or by using nonacid peat if it is
obtainable.
The future of rose breeding depends to a considerable extent on the
accumulation of fundamental information on inheritance of rose char-
acters, and on breaking away from many of the established practices.
As stated earlier, the accumulation of parentage records is of little
value unless it is accompanied by information on numbers of seedlings
grown. Undoubtedly some parents will give better progenies than
others. This information for some varieties is probably known by
some breeders bu t is not generally distributed. It also seems advisable
to start self-pollinations of many present varieties, since they are
already so heterozygous that they will probably give rise to something
of value. Above all there is a need for systematic investigation
by trained workers at institutions well equipped for genetic and
breeding work with roses. Such a program would, undoubtedly clear
up much of the present confusion.
Snapdragon
The early history of the cultivated snapdragon (Antirrhinum majus
L.) is not known. Some records indicate that it was first grown in
Italy, whence it spread to the remainder of Europe. At the present
time the species is found growing wild in many spots along the Med-
iterranean coast west of Italy. In one of the earliest published
accounts, in 1578, there were described several color variations and
two distinctive leaf types, the narrow and the broad. A little later,
five varieties, white, purple, blush, yellow, and variable, were known.
Soon after this a double-flowered form and one with variegated leaves
appeared. At the beginning of the nineteenth century several striped
and spotted varieties were listed by various growers. By 1824 a wide
range of colors existed from rich orange and yellow to white, with the
same types in reds and purples as well as many bicolor forms.
The first-named botanical varieties of Antirrhinum majus did not
appear until about 1830 or 1835. Among these were reticulatum,
youngii, and carophylloides. In 1844 a deep blood-red double-
flowered type appeared. The earlier doubles had ranged from white
to rose. In the next few decades countless horticultural varieties were
introduced each year and were sold as high as $1 per plant. At this
time propagation was entirely by cuttings. In 1850, George Parsons,
of Brighton, England, introduced a variety that was a distinct change
in the arrangement of the colors of the flower. It was white with a
deep rose band in the form of an edging to the petals. It was dis-
tributed by E. C. Henderson & Sons, in 1852, under the name of
Hendersonii.
The snapdragon did not come into its own until the latter half of the
nineteenth century. All the earlier varieties had been propagated
only by cuttings, and very little had been done with seedlings. The
966 YEARBOOK, 1937
climate of Scotland and England was very favorable for the production
of snapdragons of fine quality, and the flower soon became very
popular. The demand for newer and improved varieties stimulated
the growing of seedlings, and hundreds of new types were soon
developed.
At the present time snapdragons are roughly divided into two
groups — (1) florists' varieties and (2) types for outdoor culture. Some
varieties, of course, may be placed in both groups. In England and
Europe generally, the chief interest is in the outdoor sorts, while in the
United States the forcing or greenhouse types are the most important.
The snapdragon flower is so constructed that smaller insects find it
very difficult to gain entrance to the nectaries. It requires consider-
able effort even on the part of a large bumblebee to open the two parts
of the corolla. The flower is, nevertheless, frequently visited by large
bees, and undoubtedly considerable cross-pollination occurs. Because
of this situation, varieties of snapdragons grown for seed should be
separated a considerable distance from others. This is especially
important for florist varieties, where it is essential that strains be true
for type and color.
The practice of growing snapdragons from seed did not become very
general until early in the present century. In England and France,
seed had been offered by various seedsmen for some time. Most of
the old standard varieties, however, were still increased solely by
cuttings. In this country, nearly all florists propagated entirely in
this manner. As a result many local varieties arose but were not
widely distributed. In 1913, snapdragon rust suddenly appeared in
the vicinity of Chicago. It had been known in California and along
the Pacific coast since 1896. Within a few years after its appearance
the disease spread to all sections of this country, to Mexico, and to
Canada. The result was almost disastrous to greenhouse snapdragons
and practically eliminated propagation by cuttings. The moist con-
ditions and warmth in the cutting bench were also the optimum
conditions for snapdragon rust. This situation, and the fact that the
disease was not seed borne, stimidated development of better
seed-propagated strains. Within a short time a great number had
appeared, and today the total list "includes many hundreds of
varieties.
Most of the present-day varieties have probably arisen from
chance crosses made when the commercial seed crop was produced.
Even though the seedsman rigidly removes all off-colors and types,
the seed produced will usually contain some crosses made by bees.
The florist or grower then finds offtype plants the next year. In
addition to this source of contamination it is also verjr probable that
some strains usually contain a few hybrids, which carry recessive
characters that do not show up until the next year.
Following the widespread distribution of rust, the popularity of the
snapdragon began to wane in this country. The florists were able
to control the disease under glass, to some extent, by careful attention
to watering and maintaining a temperature unfavorable to its develop-
ment. Plantings outdoors, however, continued to suffer, and the
snapdragon began slowly to disappear from parks and home gardens.
In California the growing of snapdragon seed was a rather precarious
FLOWERS 967
undertaking. In some years a fair crop might be secured, but on the
average the yields were very poor. Many attempts to control the
disease by spraying were on the whole unsuccessful.
In 1922 E. B. Mains, then at Purdue University, found two snap-
dragon plants that showed some resistance to rust. In 1927 he dis-
tributed seed to several investigators. Continued selections and self-
pollinations in descendants of these strains finally resulted in the
development of highly resistant strains of snapdragons. The in-
heritance of this resistance has been studied by Emsweller and Jones
(117), White (545), and Mains (827). In all cases resistance was due
to a dominant gene. The inheritance of resistance is shown in figure
22. At the upper left are shown a flower and leaf of a susceptible
variety; in the upper right a flower and leaf of a resistant plant;
directly between and below, a flower and leaf from the hybrid resulting
from a cross between susceptible and resistant.' Since resistance is
dominant, the first-generation hybrid is completely free from rust.
At the bottom are shown flowers and leaves from four of the second-
generation plants. Three are resistant and one is susceptible. This
count of 3 to 1 is the typical Mendelian ratio when a single pair of
contrasting genes is involved. The actual figures from such a cross
made in California were as follows: All of the 562 first-generation
hybrid plants were completely resistant. One of them was self-polli-
nated and 550 second-generation plants were grown from the seed.
In this large popxilation 405 plants were resistant and 145 were
susceptible. A perfect 3:1 ratio would have been 413 resistant to 137
susceptible. The ratio actually secured was off just eight plants.
Such a small deviation is not significant, and the ratio secured un-
doubtedly represents what is called a simple monogenic segregation.
Resistance was also found in other Antirrhinum species imported from
western Europe by the Division of Plant Exploration and Introduc-
tion, but these were not used in the breeding of the rust-resistant
strains mentioned.
Recently in several localities in California, some of the supposedly
resistant plants have again succumbed to rust. Such a situation is
not unusual, being common in grain varieties bred for resistance to
certain strains of the cereal rusts. It is possible that the condition
in California is caused by a new strain or physiological form of the
rust organism. Since the rust parasite on the snapdragon is itself a
small plant, it is not unusual that it should produce a new strain able
to attack otherwise resistant plants. If this sho\ild prove to be the
situation, the production of rust-resistant strains of snapdragons will
bo more difficult in those sections where more than one physiological
race of rust occurs.
The genetics of the snapdragon has been extensively studied by a
large number of workers. The inheritance of color is very complex.
According to Miss Wheldale, magenta is in general the most dominant
color and yellow the most recessive. By this is meant that magenta
is dominant to practically all other colors, while yellow is usually
recessive to all others. This explains why seedsmen find that yellow
varieties and strains are usually very easy to purify. Since yellow
is recessive, plants can exhibit this color only when pure for it. In
the same investigations, crimson was dominant to bronze, bronze to
*
A
"S
o
0=
-: I _
B
s
So
to
©
©
Figure 22.— The way in which rust resistance is inherited in the snapdragon: A, Flower and leaf of the susceptible variety; B, those of
a resistant plant; C, resistant hybrid resulting from cross-pollination of A and B; D, E, F, G, flower and leaf from each of four plants
descended from the resistant hybrid C; this second hybrid generation had a ratio of 3 resistant plants to 1 susceptible.
FLOWERS 969
yellow-tinged bronze, magenta to rose doreo, and rose dore^ to ivory-
tinged rose doree\ Delilah forms, in which corolla lips are colored
and tube is colorless, were recessive to the corresponding nondelilah.
For example, crimson was dominant to crimson delilah.
Stock, Double-Flowered
The early history of the stock (Matthiola incana (L.) R. Br.) is very
obscure. The first authentic records indicate that it was known to
the Greeks and Romans and prized by them chiefly as a medicinal
herb. By 1542 at least three colors, purple, red, and white, were
known, but only in single-flowered types.
The first mention of a double form was in 1568, when a Belgian
botanist, Dodvens, described it in a paper dealing with sweet-smelling
flowers suitable for chaplets or garlands; and in 1581 an actual
illustration appeared. At this time the flower was described as
being so double that it was completely sterile. It is not known just
when the double form appeared, but it was probably a mutation from
the single. From the scant records of the period it seems that the
only method of reproducing it was by cuttings. It was not until
1629 that any statement appeared indicating that double-flowered
plants could be obtained from seed of singles.
Unfortunately, one of the earliest descriptions of double-flowered
stock stated that the doubling was the result of special treatment
and frequent transplantation. This belief was held for a long time
and many special practices based on superstition developed in the
culture of stocks. One of the most interesting descriptions of such
practices appeared in a book on gardening in 1675:
Single Flowers Doubled
Remove a plant of stock when it is a little woodded and not too greene, and
water it presently; doe this three days after the full, and remove it twice more
before the change. Doe this in barren ground, and likewise three days after the
new full Moon remove againe, and then remove once more before the change.
Then at the third full Moon, viz., eight days after, remove againe, and set it in
very rich ground, and this will make it bring forth a double flower; but if your
stocks once spindle, then you may not remove them. Also, you must shade
your plant with boughs for three or foure dayes after the first removing; and so of
Pinks, Roses, Daysies, Featherview, etc., that grow single with long standing.
Make Tulipees double in this manner. Some think by cutting them at every
full Moone before they beare to make them at length to beare double.
As mentioned earlier, the double-flowered stock plants _ were
propagated by cuttings, but how they came from seed of the singles
remained a mystery until it was cleared up by the genetic and
cytological research of Saunders (463), Frost (185), and Philp and
Huskins (408). For a long time it was generally believed that the
double-flowers produced some pollen, which fertilized the singles and
formed seed that produced doubles. Directions are still occasionally
given for selection of seed from single-flowered plants surrounded by
doubled-flowered. An examination of the double flowers, however,
discloses no pollen whatever, and it seems certain that if any is ever
produced, it is only on exceedingly rare plants.
The differences between a single and a double flower are very
striking. The single has four petals, four stamens, and a pistil.
When fertilized it produces a long, narrow, flattened fruit containing
1 38004 ° — 37 62
970 YEARBOOK, 193 7
from 30 to 60 seeds. The double flower is composed entirely of petals,
which vary from 40 to 70 per flower. There is no trace of stamens or
pistil, and, of course, no seed is formed.
The double-flowered plants are desired by both florists and gar-
deners, and because of this there is active competition among growers
of stock seed to produce high double-throwing strains. Accurate
counts made by seedsmen have revealed many strains with 80-per-
cent and a few with as high as 90-percent doubles. Usually, however,
the proportion secured by florists and home growers is far less. The
seedsmen themselves encounter sharp fluctuations ; a strain producing
as high as 80-percent doubles one year may drop to 50-percent or
less the next. As a result of this apparent instability, seedsmen,
florists, and gardeners have entertained a belief that doubleness
must be controlled by some external environmental factor or factors.
Modern genetic research has now found the fairly simple explana-
tion of this situation. It also points the way to production of rea-
sonably nonfluctuating, double-throwing strains that produce the
maximum percentage of doubles. When a large number of single
plants are self-pollinated and all seedlings of each one saved, it has
been discovered that the singles are of three sorts. Type 1 produces
only single-flowered plants, type 2 produces 3 single-flowered plants
to 1 double-flowered, and type 3 produces about 54 percent of double-
fknvered plants and 46 percent of single-flowered. The single-flowered
progeny of type-1 singles never produce any doubles in their selfed
progenies; they are pure for singleness. The single-flowered progeny
of type-2 singles are of two kinds, one-third being pure for singleness
and two-thirds like type 2, that is, producing progenies with 3 singles
to 1 double. Most of the single-flowered progeny of type-3 singles
repeat the performance of their parents, each again producing about
54-percent doubles.8
It is now easy to understand how fluctuations in percentage of
doubles may occur from generation to generation. Even though a
seedsman practices careful plant selection and saves seed only from
the high-double strains, he cannot predict with accuracy the ratio of
doubles to singles from year to year. It seems highly probable that
nearly all stock seed is a mixture of all three types of singles. The
percentage of doubles that will develop in any strain, then, is influenced
by the number of pure and heterozygous singles that were in the seed
field. Since at present there is no certain method of distinguishing
the three types of singles except by a progeny test it seems that with
ordinary methods of seed production the number of doubles will
continue to fluctuate from generation to generation.
The preceding explanation accounts for yearly changes in the pro-
portion of doubles, but it does not explain the occurrence of strains
with more than 54 to 57 percent. In fact, it sets such an amount as
the maximum proportion that can be secured. How can the strains
with over 80 percent of doubles be explained? Miss Saunders has
given the explanation. About 20 years ago she noticed for several
years the high percentage of doubles developing in a bed of stocks.
It occurred to her that some sort of artificial selection could account
b It has been shown that occasional pure single plants appear even in type 3. They, of course, brine
down the percentage of doubles expected from this type and are an additional source of confusion.
FLOWERS 971
for it. A few years later she planted 8 to 10 seeds in each of a large
number of pots. When the seedlings were well established, those in
each pot were numbered according to their size. When the plants
finally bloomed, it was found that most of the large ones were doubles
and the small ones singles. In 1923 White (546) at the Maryland
Agricultural Experiment Station conducted a very similar experiment.
He grow a large number of seedlings and then graded them into
groups on the basis of size. When the plants bloomed, he too found
that most of the large ones were doubles.
S. L. Emsweller has also investigated the problem in genetic studies
with stocks. The seedlings were not graded by size, but as soon as
the first true leaves were developed, about 150 plants from each of
several varieties were transplanted into small pots. All seedlings of
a progeny were saved. When the small plants were established, the
height, spread, and stem diameter of each were measured each week
until the plants began to bloom. They were then classified as doubles
and singles, and the mean height, spread, and stem diameter for each
group were computed for the weekly intervals. In all cases it was
very clear that the double plants were more vigorous than the singles,
even in the seedling stage. This does not mean that the smallest
double plant was larger than the largest single; there were always
a few plants of each type that overlapped. It was possible, however,
by selecting only the very largest seedlings, to secure 85 to 90 percent
of doubles (fig. 23).
Thus the occurrence of unusually high double strains is readily
explained. If anyone, florist or gardener, has more seedlings of stocks
than are needed, he will invariably discard the weak, small ones and
save the largest. On the California flower-seed ranches, stock seed
is sown in rows in the field. When the seedlings have become well
established they are thinned by hand, and naturally the stronger
plants are left. This readily explains the frequent occurrence of rows
with 80 to 85 percent of doubles. Such rows, of course, came from
parent plants that gave the highest possible percentage of doubles.
In the light. of these facts, certain recommendations for growing
seed of stocks can be made. In the absence of definite information
on natural crossing in stocks, it is advisable to self-pollinate all plants
selected. A small sample of seed from each selfed plant should be
sown in a separate row. Random samples of these seedlings, the first
50 in each row, should be transplanted, the lots again being kept sepa-
rate. These trial plantings will indicate the genetic type of the parent
of each row. Seed from pure singles will give only single-flowered
plants; that from simple hybrids, about 3 singles to 1 double; and that
from the so-called ever-sporting type, slightly more than 50 percent
of doubles. The seed of all pure singles and simple hybrids can then
be discarded and a seed crop grown from plants that produced the
maximum number of doubles. Such a procedure would require 2 to 3
years but would certainly give high-quality seed. In many sections
of California it is possible to maintain such a planting for several years.
Emsweller has done so and secured a greatly increased seed yield the
second year. It is recognized, of course, that this method would
involve extra expense, but it has been profitable with delphinium,
hollyhock, and columbine, and it should be with stocks also. If seed
972
YEARBOOK, J93\
of this type were generally available, and florists and gardeners
rigidly discarded all weak seedlings, they should have little trouble
in securing stocks running close to 90 percent double. This means
that over twice the ordinary amount of seed should be planted, since
slightly more than half the seedlings would be discarded in thinning
out on the basis of size.
There are several types of stock plants (fig. 24) varying in habit of
growth, earliness, and flower color. Unfortunately the importance of
Figure 23. — Stock seedlings selected for size after transplanting: A, Group of the
extremely large plants, 90 percent of which were double-flowered; B, smallest plants,
18 percent of which were double-flowered.
the problem of double flowers has retarded work on inheritance of
these characters. Some data are available, however, on inheritance
of tall versus dwarf plants and branching versus nonbranching.
Tall is dominant to dwarf, and in the second hybrid generation there
will be found three tall plants to one dwarf. The situation is not so clear-
cut for branching crossed with nonbranching. The first-generation
hybrid is branched, and in the second generation there is a close
approach to a ratio of 3 branching to 1 nonbranching. These non-
branching plants, however, have some tendency toward branching,
which the original nonbranching parent plant did not have.
The future breeding work with stocks will probably be concerned
with the inheritance of other important characters. There is also
need for the discovery of some simple seedling characteristic to enable
florists and gardeners to select with certainty double-flowered plants
in the seedling stage.
FLOWERS
973
Figure 24. — Four types of double-flowering stock showing variation in growth habit.
There are many varieties of each kind including a wide range of colors. {A) The tall
ten weeks and (B) the dwarf ten weeks types are used mostly for bedding, are very
early bloomers, and are easy to grow. (C) The imperial (brandling) and (£)) the
column (nonbranching) types are grown mostly under glass by florists. The column
sorts (D) are valued for their tall single spike and for adaptability for close planting,
thus yielding more salable flower spikes per square foot of greenhouse bench.
974 YEARBOOK, 1937
Sweet Pea
The sweet pea (Lathyrus odoratus L.) was introduced into the
Netherlands and England from its native Sicily in 1699. From
a figure and description published in 1700 the original type is
recognizable as a tall plant reaching a height of 6 or 7 feet, with
short flower stems bearing two blooms each. The individual bloom
was small and fragrant. The standard was erect, narrowed at
the base and cleft at the top. In color the standard was reddish
purple, the wings light bluish purple. Figure 25 shows a type
closely resembling the wild Lathyrus odoratus in comparison with a
modern flower.
The evolution of 500 or more distinct garden varieties from this
unassuming beginning has been admirably traced by Beal (40),
and the significance of mutation and hybridization in the process
has been interpreted by Babcock and Clausen (8). White forms
appeared in 1718. In 1731 Painted Lady — pink and white in place
of the purple and blue of the original type — was introduced. Scar-
let, a brighter self-colored variety presumably derived from Painted
Lady, appeared in 1793. Then followed in 1806 a blue variety,
in 1817 a striped type, and in 1824 the so-called yellow, more prop-
erly primrose. New Large Purple, listed in 1845, implies an im-
provement in size of bloom. Marked increase in size also occurred
in the Countess Spencer variety (1904). The original two flowers
per stalk were increased to three with the advent of Invincible
Scarlet in 1865 and Crown Princess of Persia in 1868, and they
were further increased to four blooms per stalk in the more recent
Spencer type. The form of standard was differentiated into three
distinct types: grandiflora, erect but larger and broader at the base
than the original, appeared in 1888; hooded, with edges inrolled, is
an early type; Spencer, with waved standard, is a more recent
development. Changes in habit of growth include two recessive
dwarf types, the cupid (prostrate) and the bush (erect), and the
commercially important winter-flowering type. The winter-flower-
ing sorts are distinguished from other sweet peas by prompt growth
and flowering under winter forcing conditions and by lower stature
and shorter flower stems. Blanche Ferry, the first of the winter-
flowering types, was selected by the wife of a quarryman in northern
New York for 25 years before it reached the trade in 1889. Beal
has traced the subsequent development of the winter-flowering group
from this and subsequent mutations.
All of the changes mentioned thus far are considered in Babcock's
analysis to be due to mutation from the original type. The first
hybridization in the sweet pea was undertaken about 1880 by Thomas
Laxton, of Bedford, England. Thereafter intensive use of crossing
served to incorporate the desired colors in the commercial grandiflora,
hooded, and Spencer types and to vary the color and form of blooms
in the important winter-flowering group. The number of favorable
mutations occurring in the sweet pea in two centuries of culture is
truly remarkable. These have served as the material from which
practical breeders have constructed the varied horticultural varieties
of our day.
FLOfFERS
975
B
I
Figure 25. — A modern swecl pea (A) and a type closely resembling the wild forui (B),
from which it arose. The greatest part of (his development has taken place in the last
25 years.
Hurst {223) has presented some examples of the actual procedure
followed in producing new combinations by hybridization. W.
Cuthbertson produced the Waved King Edward variety as follows.
976
Parents
YEARBOOK, 1937
King Edward
Plain
red
!
Countess Spencer
Waved
pink
First
generation
(Pi)
Plain
red
Second
Plain
Plain
Waved
Waved
generation
red
pink
red
pink
(F2)
(9)
(3)
(3)
(1)
Waved King Edward
The expected proportions of the F2 population are supplied by
Hurst since Cuthbertson did not count the classes. Out of the
desired waved red class in F2, one-third of the plants should be pure
breeding and two-thirds segregating again 3 red : 1 pink. Cuthbert-
son also raised Primrose Spencer by a similar procedure. Hurst also
explains the synthesis of Black Knight Cupid in his own experiments:
Parents
Black Knight
Tall
purple
dark-wing
Pink Cupid
Cupid
red
light- wing
First
generation
(F,)
Wild purple
Tall
purple
light-wing
Second
genera-
tion
(F2)
Tall Tall
purple purple
light- dark-
wing wing
(27) (9)
Tall
red
light-
wing
(9)
Cupid
purple
light-
wing
(9)
Tall
red
dark-
wing
(3)
I
Cupid
purple
dark-
wing
(3)
Cupid
red
light-
wing
(3)
Cupid
red
dark-
wing
0)
Black Knight
Cupid
Black Knight Cupid was then "fixed" by saving the progeny of the
one- third of this class that were true breeding, and discarding the
two-thirds that segregated in the third generation into 3 purple : 1 red.
The synthesis of combinations in this manner is simple when the
desired genes are available in different varieties and their mode of
inheritance is known .
In addition to the many valuable mutations that have made pos-
sible the range in color and form of modern sweet pea varieties,
other mutations of minor value and actually harmful types have
FLOWERS 977
appeared. Among the mutant forms of minor or novelty interest
may be mentioned the "snapdragon" type in which the standard is
folded around the wings. This is inherited as a simple recessive to
the normal type. Recently Wright has described a variety producing
two or even three flower stalks at each node, without loss of size or
beauty of the flowers. This may be regarded as a new mutant,
evidently of minor commercial value, for no further reference to it
has appeared. The change from "long" pollen to "round" is an
example of a mutant neither useful nor harmful from the horticul-
tural viewpoint, while "contabescent" anthers, a recessive mutant
bearing abortive anthers, and the monstrous "cretin" type with
abortive pistil, illustrate harmful mutants. Stone's report of a so-
matic mutation from recessive cupid to normal tall illustrates that the
mutation process is still active in sweet peas.
Although hybridization has been widely employed, natural crossing
between varieties of sweet peas is probably infrequent. Until recently
there was no authentic record of a successful cross of Lathyrus odoratus
with any other species of the genus. Barker (11) reports success
with only one cross between species out of many attempted. This
hybrid, L. odoratus Kitty Clive X L. hirsutus (a weak annual), was
fertile ; segregation occurred in the second hybrid generation, but the
L. odoratus type was not recovered. No noteworthy ornamental type
appeared in this or later generations. A few seeds were obtained on
pollinating the first-generation hybrids from L. odoratus X hirsutus
with pollen from one of the perennial species of Lathyrus.
The modern sweet pea leaves little to bo desired in form of flower
and variety of color. A true yellow is not available though long
sought, and brighter shades of present colors are still desired, as well
as reds and pinks that do not sunburn. The duplex type, a recent
novelty with extra petals producing the effect of added size of bloom,
seems worthy of fixing and of hybridizing to extend the range of
color and types available. Resistance to diseases, particularly of the
root rot group, is needed. A hardier race of sweet peas to endure
winter cold and permit fall planting and one enduring summer heat
would serve to extend the range of satisfactory garden culture of this
excellent annual.
LITERATURE CITED
Literature citations for this article, covering 564 references on
flower breeding, are omitted from this volume because of space limi-
tations but are available in the 1937 Yearbook Separate on Improve-
ment of Flowers by Breeding.
978 YEARBOOK, 1937
APPENDIX
Supplementary Data on Lily Breeding
Classification of the species Lilium
Subgenus Eulirion: True lilies. Bulb perennial; leaves linear, lanceolate or
lanceolate-ovate.
Section 1. Leucolirion: Trumpet lilies. Flowers trumpet-sliaped, hori-
zontal or nodding; perianth segments falcate or spreading at the apex;
stamens not divergent.
Examples: Lilium candidum L., L. formosanum Stapf., L, Itmgiflorum
Thunb., L. regale Wils.
Section 2. Archelirion: Lilies with open, bowl-shaped flowers. Perianth
segments widely spreading, broadest below the middle; stamens divergent.
Examples: L. auratum Lindl. only, according to Wilson; but also L.
speciosum Thunb. and L. tigrinum Ker according to Baker. Grove
adds L. henryi Baker and L. leichtlinii Hook. f. and comments that the
dividing line between Archelirion and Martagon is arbitrary and may
need revision.
Section 3. Isolirion: Lilies with erect flowers. Perianth segments falcate,
not revolute at apex. Leaves whorled or scattered. Stamens divergent.
Examples: L. bulbiferum L., L. philadelphicum L., L. concolor Salisb.
Section 4. Martagon: Lilies with nodding flowers and strongly revolute
perianth parts. Leaves whorled or scattered. Stamens divergent. The
Turkscap group.
Examples: L. martagon L., L. chalcedonicum L., L. hansoni Leicht., L.
amabile Palibin, L. cernuum Komarov, L. superbum L., L. wiUmottiae
Wils.
Subgenus Cardiocrinum: Heart-leaved lilies. Bulbs monocarpic (flowering onlv
once) ; leaves long-petioled, ovate-cordate.
Examples: L. cordalum (Thunb.) Koidz., L. gigantewn Wallioli.
List of Lily Hybrids Arranged in Alphabetical Order
of the Seed Parents
Species names of the seed parents are followed by the author of the name, the
date the name was assigned, the section in which the species is usually placed, and
the region to which the species is native. Under the seed-parent headings are
listed the pollen parents reported to cross, named hybrids, if any, in quotation
marks, and sometimes comment on the results. The practice of indicating a
hybrid species by inserting the sign of multiplication (X) before the species
name, as L. X testaceum, has been followed.
Lilium amabile Palibin, 1901. Martagon. Chosen.
X L. martagon. Preston reports one success.
L. auratum Lindley, 1862. Archelirion. Japan.
X L. speciosum var. melpomene="L. X hoveyi."
X L. speciosum (?) = "Mrs. Anthony Waterer."
X L. speciosum. Preston reports success.
L. auratum var. plalyphyllum Baker, 1880. Archelirion. Japan.
X L. speciosum var. magnificum = "L. X parkmanni var. haywardi."
X L. speciosum var. melpomene (1) = "L. X Crimson Queen."
X L. speciosum. Stout reports success.
L. auratum var. rubrovittatum Duchartre, 1870. Archelirion. Japan.
X L. auratum. Stout reports success.
L. bulbiferum L., 1753. Isolirion. Europe.
X L. croceum (syn. L. bulbiferum subsp. croceum). Griffiths reports one
worthy hybrid."
X L. X thunbergianum (syn. L. X elegans). Berckmuller reports many
crosses. According to him the varieties incomparabile, erectum, grandi-
florum, multiflorum, and Sappho of L. X umbellatum of commerce are
referable to the cross L. bulbiferum X L. X thunbergianum. Berckmuller
FLOWERS 979
further suggests that the name L. umbellatum should be restricted to the
progeny of this cross and that a new name should be created for those
newer varieties of L. X umbellatum of commerce that are referable to the
cross L. croceum XL. X thunbergianum.
L, bulbiferum subsp. croceum (Chaix) Baker, 1873. Isolirion. Europe.
X L. concolor. Preston reports one success.
X L. dauricum. Stout reports success.
X L. davidi="L. X crovidi." L. X crovidi X L. X cromottiae = "L. X
Golden King."
X L. X elegans = "L. X Coolhurst hybrid."
X L. X elegans. Preston and Stoutreport successes.
X L. tenuifolium (syn. L. pumilum). Preston reports two natural hybrids.
XL. X thuribergianum (syn. L. X elegans). Berckmiiller reports many suc-
cesses and from the resemblance of the progeny to such newer varieties of
L. X umbellatum of commerce as Golden Fleece, Orange King, Invincible,
Splendidum, Mahogany, and Vermilion Brilliant, he considers that a new
name should be created for this cross, reserving the name L. X umbellatum
for the cross L. bulbiferum XL. X thunbergianum.
X L. tigrinum—"L. X manglesi."
X L. willmottiae— "L. X cromottiae."
L. canadense L., 1753. Martagon. Eastern America.
X L. grayi. Stout reports success.
X L. superbum. Stout reports success.
X L. tenuifolium (svn. L. pumilum). Preston reports success.
L. candidum L., 1753. Leucolirion. Europe to Western Asia.
X L. chalcedonicum. Griffiths reports promise.
X L. parryi. Grove reports success in 1914.
XL, X testaceum. Preston reports success.
X L. X testaceum. Griffiths reports success but no hybrids of promise.
L. chalcedonicum L., 1753. Martagon. Greece.
X L. candidum=L. X testaceum, natural hybrid (1830?). It is generally
agreed that L. testaceum is of this origin, but the exact time and place of
origin are uncertain. Hybrids closely resembling L. testaceum have been
reproduced at least throe times.
L. concolor Salisbury, 1806. Isolirion. China.
X L. dauricum = "L. X elegans." Berckmiiller produced this cross and found
the progeny conformed to the description of L. thunbergianum Schultes.
The latter species is therefore presumably a hybrid and synonymous with
L. X elegans.
X L. tenuifolium (syn. L. pumilum). One success by Van Fleet, according
to Griffiths.
L. dauricum Ker, 1809. Isolirion. Northeastern Asia.
X L. croceum (syn. L. bulbiferum subsp. croceum), Stout reports success.
X L. X elegans. Stout reports success.
X L. X thunbergianum (Syn. L. elegans). Preston flowered seedlings.
X L. X umbellatum. Preston flowered seedlings.
L. davidi Duchartre, 1880. Martagon. China.
X L. pseudotigrinum (?) . Preston reports success.
X L.iigrinumv&r.fortunei. Preston reports success. (Probably L. ligrinum
var. diploid.)
X L. willmottiae = "L. X davmolliae." Preston states that the cross L.
davidi (the sutchuenense form) X L. willmottiae was made in 1922. A num-
ber of seedlings sent out as "Ottawa hybrids" were later called davmolliae,
which has resulted in lack of uniformity.
L. X elegans Thunbcrg, 1811. Isolirion hybrid. Japan. Not known wild.
Berckmiiller has shown that L. elegans Thunberg (syn. L. thunbergianum
Schultes) is a hybrid, L. concolor X L. dauricum.
X L. croceum. Preston and Stout report success.
X L. dauricum. Stout reports success.
Preston reports L. X thunbergianum X L. dauricum successful
L. grayi S. Watson, 1879. Martagon. Eastern United States.
X L. canadense. Stout reports success.
L. hansoni Leichtl., 1874. Martagon. Northeastern Asia.
X L. X dalhansoni. Preston reports success.
X L. X marhan. Preston reports success.
980 YEARBOOK, 1937
X L. martagon. Griffiths reports interesting seedlings.
X L. martagon album "L. X St. Nicholas." Preston also reports sun ess
X L. medeoloides (?) . Stout reports success.
XL. tenuifolium (syn. L. pumilum). Stout reports 42 pollinations failed
40 yielded capsules, only 3 seeds germinated.
L. henryi Baker, 1888. Martagon. China.
X L. auratum
X L. candidum
X L. X princeps seedling
X L. regale } Preston reports success.
X L. speciosum
X L. X lestaceum
X L. tigrinum
X L. leucanthum var. chlorasier = "L. X kewense."
X "3 Asiatic Martagons" successful according to Griffiths.
XL.sutcfiuenen.se (?). Stout reports that plants from bulbs received from
C. P. Horsford under this name were self-fertile and fertile with L will-
mottiae pollen.
L. humboldtii Roezl. and LeichtL, 1871. Martagon. California.
{"Frances Larrabeo"
"Mercer Girl"
"Vashon"
L. humboldtii var. bloomerianum (Kellogg) Jepson, 1922. Martagon. California.
X L. humboldli var. magnificum]
X L. parrxji (?) \ Stout reports success.
X L. roezli J
L. humboldtii var. magnificum Purdy, 1897. Martagon. California.
X L. X Amos Perry = "L. X gloriosum."
X L. humboldli var. bloomerianum} Di .
X L. roezli j "tout reports success.
X L. pardalinum Kellogg. "Cyrus Gates", "Douglas Ingram", "John
McLaughlin", "Kulshan", "Sacajawca", "Shuksan", "Star of Oregon "
lhese are all Fi seedlings from Griffiths' crosses. Further lines of gar-
r , „ . ?2. merit were expected from intercrossing and backcrossing these
L. kelloggn Purdy, 1901. Martagon. California.
X L. canadense\
X L. humboldli
X L. parryi ^Feeble fertility is reported by Stout.
X L. parvum
X L. roezli J
L. leichtlinii var. maximowiczii (Kegel) Baker, 1871. Martagon. Eastern Asia
X L. dauricum var. venustum f. batemanniae = "L. X horsfordi." Griffiths
also reports a hybrid worth introducing.
X L. tigrinum. Preston reports one success.
X L. wilbnotliae = "L. X Maxwill."
L. leucanthum Baker, 1901. Leucolirion. China.
X L. X George C. Creelmanl ^ .«. ., , ,
L reaale I Griffiths reports successful
XL. regale ' I Griffiths reports successful crosses, the first
X L. sargenliae J two yielding promising hybrids.
L. leucanthum var. chlorasier (Baker) Wilson, 1925. Leucolirion. China
X L. regale = "L. X centigale."
XL. sulphureum (syn. L. myriophyllum var. superbum).
L. longiflorum Thunberg, 1794. Leucolirion. Eastern Asia.
X L. regale. Preston reports one success.
L. X marhan (L. martagon var. album X L. hansoni). The Netherlands, 1880.
X L. X dalhansoni ]
X L. hansoni ^Preston reports successes.
X L. martagon var. album]
L. martagon L., 1753. Martagon. Europe and Asia.
X L. hansoni. Stout reports success.
L. martagon var. album Hort., 1880.
X L. hansoni = "L. X marhan." The varieties "Ellen Willmol.t" and
' E. J. Elwes" were derived from "L. X marhan."
Grove reports successful crosses but no pro-
1 gcny of note.
FLOWERS 981
X L. bolanderi S. Wats.
X L. callosum Sieb. and Zucc.
X L. carniolicum Bornh.
X L. columbianum Hanson
X L, davidi
X L. grayi S. Wats.
X L. kelloggi Purdy
X L. maritimum Kellogg
X L. medeoloides A. Gray
X L. pardalinum Kellogg
X L. willmottiae
L. martagon var. dalmaticum Elwes, 1877.
X L. hansoni = "L. X dalhansoni."
X L. medeoloides = "L. X M armed."
L. martagon and varieties.
X L. hansoni = "Backhouse hybrids": "Brocade", "Golden Orb", "Mrs.
R. O. Backhouse", "Sceptre", "Sutton Court", etc.
L. myriophyllum var. superbum (Baker) Wilson, 1925. Leucolirion. Upper
Burma. (Syn. L. sulphureum Baker 1892.)
X L. regale = "L. X sulphurgale."
F2 seedlings are also sold as "L. X sulphurgale."
L. X sulphurgale X L. X princeps = "Crow's Hybrid."
L. neilgherrense Wight, 1853. Leucolirion. Southern India.
X L. wallichianum = "L. X bwmhamense."
L. pardalinum Kellogg, 1863. Martagon. California, Oregon.
X L. humboldti = "L. X pardaboldti." "Dimsdale variety" is a selection
from the hybrid.
Purdy believes that Luther Burbank's hy-
brids fall into these four groups, and an
additional untraceable group. Many other
species crosses were attempted but not
kept separated. Some excellent types
were produced but L. burbanhi, which
bears the originator's name, is "a non-
descript medley" — Purdy.
X L. columbianum. Considered promising by Griffiths.
X L. superbum. Successful but not promising. — Griffiths.
L. parryi S. Wats., 1878. Leucolirion. California.
X L. humboldti var. magnificum = "L. X Amos Perry."
X L. pardalinum = "L. X burbanhi."
= "Napier's variety."
= "L. X Frances Fell."
— "L. X Peter Pugct." Grove states this cross yields fine
hybrids, some of which are yellow-flowered.
X L. parvum var. luleum = "L. X roemeri."
L. parvum Kellogg, 1863. Martagon. California, Oregon.
X L. pardalinum} According to Grove these hybrids are attractive but lack
X L. parryi / "staying power."
L. philadelphicum L., 1762. Isolirion. Eastern North America.
X L. dauricum — "L. X phildauricum." Skinner discusses his recent crosses
in a letter to Preston.
L. pseudotigrinum (?).
X L. callosum. Preston reports one success.
L. pumilum DC, 1813. Martagon. Northeastern Asia. (Syn. L. tenuifolium
Fischer 1812.)
X L. martagon album — UL. X Golden Gleam." According to Grove,
"Golden Gleam" was originally an authentic hybrid but has since been
propagated by seed.
X L. X elegans '
X L. martagon
X L. Teg%90n Var' aftMmpeston ™ports successful crosses.
X L. speciosum
XL. X testaceum )
X L. washinglonianum Kellogg
X L. humboldti
X L. parryi
X L. maritimum
•Preston reports successful crosses.
982 YEARBOOK, 1937
X L. chalcedonicum "1
X L. monadelphum >Skinner reports successful crosses.
X L. regale J
L. regale Wilson, 1912. Leucolirion. China.
X L. tenuifolium. Claimed by Theodore Albert.
X L. auratum
X L. candidum
X L. longiflorum
X L. speciosum var. rubrum
X L. X sulphurgale
X L. X lestaceum
X L. iigrinum
XL. sargentiae \a, , ,
X (L. s—to X L. regale seedling) /Stout rePorts success-
X L. X George C. Creelman.
X L. leucanthum 1
X L. \7pTuZm Griffiths rePorts s»ocessM crosses"
X L. X sulphurgale}
X Li ftLm}Griffith8 mentions possible successes.
L. »-oe«K Regel, 1870. Martagon. California.
X L. parryi. Grove records a fine hybrid of good constitution.
X L. columbianum]
X L. humboldti >Stout reports success.
X L. parryi J
L. sargentiae Wilson, 1912. Leucolirion. China.
X L. henryi = "L. X aurelianense."
XL, X aurelianense. Debras reports seedlings growing, also seedlings of
"L. X aurelianense" selfed.
X L. regale = L. X princeps (syn. "L. X sargale"). First appeared as a
chance seedling. J. W. Crow had some interesting seedlings from the cross
L. X princeps X L. X sulphurgale.
= "L. X George C. Creelman."
= L. X Pride of Charlotte. This hybrid is reported to come true from
seed. Preston and Stout also report successful crosses.
X L. X aurelianense. Debras reports success.
L. speciosum Thunbcrg, 1794. Martagon. Japan.
X L. auratum. Preston and Stout report successes.
X L. candidum
X L. henryi
X L. IpeiLum var. album}VTCston reP°rts ««>oeBBful crosses
X L. X testaceum
X L. iigrinum )
X L. iigrinum seedling raised by Crow did not reach flowering size.
L. speciosum var. album Hort.
X L. iigrinum.
L. speciosum var. magnificum llort.
X L. speciosum var. melpomene. Remarkable hybrid. Griffiths.
X L Iigrinum I ^Earl^: "losses were successful but seedlings were lost. Preston
L. speciosum var. rubrum Hort.
X L. auratum = "L. X parkmanni."
X L. iigrinum. Preston reports early seedlings were lost.
L. superbum L., 1762. Martagon. Eastern North America.
X L. roezli }Uollt reI>orts success.
L. X testaceum LindL, 1845. This hybrid, L. chalcedonicum X candidum, was
first recognized in Germanv in 1836 and probablv originated in the Netherlands
about 1830.
X L. candidum= "White Knight." Preston and Stout also report success.
X L. chalcedonicum ="L. X beerensi." Griffiths reports this cross promising.
FLOWERS 983
L. iigrinum Ker, 1810. Martagbn. Eastern Asia.
X L. elegans var. wallacei (syn. L. dauricum var. wallacei (Wallace) Wilson).
Stout reports success.
X L. leichllini var. maximowiczi—"L. X tigrimax." Stout also reports
success.
X L. X tigrimax. Preston reports success. Stout reports success with pollen
of the Fi hybrid L. iigrinum X maximowiczi.
X L. sutchuenense. Stout reports success.
X L. willmottiae. Preston has flowered seedlings.
L. iigrinum var. fortunei Hort., 1866. Preston describes a form of L. iigrinum
referred to this variety by Wilson, which is self-fertile. In a recent paper
Preston names this form L. iigrinum "var. diploid."
X L. auratum \ -r, , ,
X L. leichllini var. maximoioiczi)V™sion rePorts success-
L. X umbellatum Hort., 1874. Berckmuller considers that this form is a hybrid —
L. bulbiferum X£.X thunbergianum (L. X elegans). The uameL. umbellatum
has been used by Dutch hybridizers for various hybrid lilies of the upright-
flowered type.
X L. bulbiferum. Griffiths reports one seedling of merit.
X L.Xwillcrovidi="L. X Fire King."
L. willmottiae Wils., 1913. Martagon. China.
X L. X crovidi="L. X willcrovidi."
X L. dauricum seedling="I/. X Grace Marshall" 1
"L. X Lila McCann" Prcston
"L. X Lilian Cummings" f L rCbton-
"L. X Phyllis Cox" ' J
X L. X elegans "Mahogany" — "L. X scottiae."
X L. davidi \
X L. grayi [
X L. spedosum iPrcston reports successes.
X L. iigrinum var. fortunei I
X L. X umbeUatum )
X L. iigrinum "]
X L. pseudotigrinum >Stout reports successes.
X (L. henryi X L. sutchuenense)}
X L. farreri 1
X L. rle°galedelPhUm S^cessful crosses reported by Skinner.
X L. washingtonianum]
Genetic Studies ox Ornamental Plants
The utilization of genetic science in practical breeding of flowers is in its infancy.
The following brief survey indicates .the scope of genetic work on ornamental
plants. It will be noted that the characters studied are often of little fioricultural
interest, and that plants of minor ornamenial value have received attention, while
many flower favorites have been nearly or wholly ignored. The object of genetic
research has been largely to extend knowledge of the operation of the laws of
heredity. Ornamental plants have been studied chiefly because they offer easily
recognizable characters, and because they arc convenient to grow.
The material assembled here is necessarily brief. No claim to completeness is
made. Those interested in specific plants will usually find further details in the
original publications cited in the bibliography, which appears in the 1937 Year-
book Separate, Improvement of Flowers by Breeding. References are indicated
by italic figures following the names of authors in parentheses. Much of the
literature up to 1929 is covered by Matsuura (33.9), and up to 1930 by Warner,
Sherman, and Colvin {532).
Abuiilon. (Klebahn, 301.)
In crosses between Abuiilon striatum and A. thompsoni flower and loaf char-
acters proved hereditary. A range of color shades in Fi suggested hybridity
in the parents. The Fi proved largely sterile.
Althaea. (Saunders, 458.)
In a cross of double-flowered X single-flowered the Fi was intermediate; the
F2 ratio was 1 single: 2 intermediate: 1 double.
Amaranthus caudalus L. (De Vries, 530.)
The red-leaved type is dominant to the green.
984 YEARBOOK, 1937
Anagallis arvensis L. (Heribert-Nilsson, 200; Weiss, 538.)
Scarlet-flowered X blue produced scarlet flowers in Fj; in F2 scarlet and
blue in no usual Mendelian ratio. Pink (nearly white) X red-flowered yielded
red flowers in Fij in F2, 3 red : 1 pink-flowered^
Anemone. (Hildebrand, 204; Rosen, 44®, 444-)
Dark-blue flower color (Anemone hepatica) X white (A. acutiloba) produced
light blue in Fj. Light blue (.4. angulosa) X dark blue produced an intermediate
color in Fi. Blue and red are dominant to white. Red X white often yielded
blue in Fi, and in F2 a ratio of 9 blue : 3 red : 4 white.
Antirrhinum calycinum Lam. (Saunders, 462.)
Red corolla color is dominant to white, and glabrous stems and capsules to
hairy. In the Fi of red X white corolla, the red color is both diluted and
retarded, i. e., the flowers developed in later growth are deeper red than early
flowers of the same plant.
Antirrhinum hispanicum Chav. (Baur, 84; Filzer, 128; Sirks, 484-)
In a cross between two self-sterile plants, the Fi was divisible into two classes,
one fertile with either parent, the other with one parent only. Filzer explained
Baur's data by assuming three genes for sterility, one of which was common to
the two parents.
Antirrhinum majus L. (Bateson, 16; Baur, 27, 28, 29, SO, 81, 82, 83, 85, 86, 37,
88, 89; Gairdner and Haldane, 140; Hackbarth, 160; Hertwig, 201; Herzberg-
Frankel, 202, 208; Hiorth, 208; Kuckuck, 806; Saulescue, 448; Scherz, 468;
Schiemann, 469; Stein, 492, 493; Stubbe, 499, 500, 601; De Vries, 529; Whel-
dale, 541, 542, 543.)
Research has given information about some 200 genes in this plant. Color
inheritance is complex. Wheldale interprets color expression on the basis of
at least seven interacting genes. Baur adds to these a number of basic genes
further conditioning, modifying, or intensif\'ing color expression. Baur and
his students and others have studied in a large number of mutants the inheri-
tance of form of flower, form of and color distribution in leaves, and stem
peculiarities. Most of these mutants, which appeared spontaneously in Baur's
cultures, are defective types, and all but one, -crispa" (conditioning wavy leaf
margins), are recessive. "Crispa" is dominant, distinctly deleterious in the
heterozygous condition, and lethal when homozygous. Mutations have been
artificially induced in snapdragon by treatments with radium (Stein), X-rays,
ultraviolet light, and temperature shocks (Stubbe). Dwarfs and leaf defects
are common; all the induced mutants are inferior types. In general the
mutants are similar to spontaneous mutants but appear in higher frequencies.
Stubbe records the appearance of some mutants not observed previously, and
Stein reports a tendency to gall formation induced by radium. Baur found
chemical treatment of stem tips ineffective, and Hiorth obtained no gene muta-
tions from heat-treated pollen grains.
Several instances of linkage have been determined in the snapdragon. Gaird-
ner and Haldane have reported a case of balanced lethals, i. e., two closely
linked genes, each causing death of the individual when homozygous, per-
mitting a heterozygous plant to breed nearly true, through elimination of the
two homozygous classes.
Antirrhinum species hvbrids. (Baur, 34; Brieger, 55; Gruber, 156; Gruber and
Kuhl, 157.)
Baur has studied the inheritance of fertility and sterility in several species
of Antirrhinum. A. ibanyezi, A. molle, A. glutinosum, A. hispanicum, etc., are
fully self-sterile; a form of A. majus is fully self-fertile. Crosses between self-
sterile and self-fertile forms yielded in F2, 15 self-fertile : 1 self-sterile. Gruber's
and Brieger's results indicate that the inheritance of sterility is often more com-
plex. Gruber and Kuhl found the radial (peloric) flower character linked with
genes for self-sterility.
Aquilegia vulgaris L. (Baur, 30, 32; Brieger, 54; Kristofferson, 304)
On selfing a dark blue plant, Kristofferson obtained a ratio of 9 dark blue :
3 red : 3 light blues : 1 white. Two genes were assumed, one having additional
effects on plant color extension, producing self-color when dominant and white-
margined when recessive. Baur found two types of chlorophyll defects —
"chlorina" (yellowish green) and "variegata" were each monogenic recessive
to the normal green. Chlorina is also a monogenic recessive to variegata.
Brieger found flower colors segregating in the pattern of 9 blue : 3 red : 4 white,
FLOWERS 985
with mortifying genes controlling intensity of color. Spurless is determined
by two polymeric dominants over spurred.
Aquilegia species hybrids. (Anderson and Schafer, 5, 6; Blaringhem, 51; Ska-
lmska^?-.)
Anderson and Schafer found wide petals dominant over narrow and medium
length spurs over very long or very short ones in first-generation species hy-
brids. They observed 16 percent of natural crossing between two strains of
Aquilegia vulgaris, but none between A. vulgaris and A. skinneri. Skalinska
reports that anthocyanin flower color is linked with straight spurs. A.
calif omica X A. flabellala yields a fertile Fi generation and shows both parental
types in F2. The reciprocal cross differs in Fi and shows no paternal type in
F2. Blaringhem has reported on inheritance in crosses of a mutant tvpe hav-
ing only female flowers with normal A. vulgaris, and also with A. sib'irica and
A. chrysantha.
Arabia albida Stev. (Correns, 97.)
Correns studied three types of pcriclinal chimaeras in this plant. One type,
"leucodermis", is inherited only through the female parent, not through the
pollen (maternal inheritance); the other two types are Mendelian recessives.
Argemone. (Correns, 85; Meunissier, 844-)
Yellow-flowered Argemone mexicana X pale yellow A. ochroleuca yielded Fi
plants of intermediate color. A. mexicana X A. platyceras (white-flowered)
produced plants of intermediate type in F1( and in F2 a new color tvpe and
several new forms in other characters.
Arum maculatum L. (Colgan, 77.)
Colgan raised 11 seedlings from a plant having black spots on the leaves; of
these 5 bore spotted leaves, 6 lacked spots.
Aster tripolium L. (Fleming, 131.)
Fleming reports that purple flower color is dominant to pink and that pink
is dominant to white.
Atropa bellado-nna L. (Batcson and Saunders, 23.)
Differences in color of flowers, fruits, and stems, which distinguish the variety
lulea from the type of the species, showed monogenic inheritance.
Barbarea vulgaris R. Br. (Anderson, 7; Dahlgren, 105.)
One type of variegation shows maternal inheritance only. Another type
differs from the normal green type by duplicate recessive genes. Somatic
segregation also occurs.
Begonia. (Bateson and Sutton, 26.)
Inheritance of double versus single flowers showed irregularities not fully-
accounted for.
Bryonia dioica Jacq. (Jones and Rayner, 275.)
Absence of bloom on the berry proved to be a monogenic dominant to its
presence. In a cross between a variety with deeply lobed, rough, dark -green
leaves and a variety with less deeply lobed, smoother, and paler leaves, the Fi
was intermediate, and new types appeared in the F2 population. Number of
carpels and number of vascular bundles in the stem were also studied.
Callistephus. (Fleming, 131.)
From the results of natural crossing it is inferred that purple flower color is
dominant to red, and red to white. Deep pink is dominant to white.
Campanula carpatica Jacq. (Pellew, 403, 4^4-)
Blue flower color is a simple dominant to white, but irregular segregation
occurs in formation of the pollen grains, so that 97 percent carry the gene for
blue, and only 3 percent carry the gene for white. Paler shades of blue arc
usually recessive to darker shades. White or "patched" seedlings proved
recessive to the normal green type.
Campanula medium L. (Correns", 87; Lathouwers, 809.)
The "hose-in-hose" or "cup and saucer" type with petaloid calyx proved to
be a partial dominant to the normal. In F2 a ratio of 3 "hose-in-hose": 1
normal appeared. Lathouwers also crossed rose-flowered X white; the Fi
generation was dark violet; in F2 segregation occurred in the ratio of 9 colored:
7 white, the colored forms falling into the ratio of 9 dark violet: 3 violet: 3
lilac : 1 rose-flowered. This was interpreted on the basis of two complementary
genes for formation of anthocyanin and two further genes for color singly con-
ditioning lilac and violet, and together producing dark violet, with rose the
double recessive.
13S004°— 37 o;j +-
986 YEARBOOK, 1937
Campanula persicifolia L. (Batcson, 18.)
A dwarf form very distinct from the normal type in appearance proved to
be a monogenic recessive to the normal.
Carina. /Honing, 218, 21/,, 215, 216, 217.)
Honing studied the behavior of some 18 genes in Canna glaum, C. indica,
and in segregates from crosses between these species. The inheritance of red
leaf margin is complex; in one cross the presence of three complementary genes
was indicated, in other crosses monogenic and digonic ratios appeared. A
monogenic difference was found responsible for the deep scarlet flower color of
C. indica as contrasted with yellow flowers of C. glauca. Further studies of
intensity of flower color, flaking in the flowers, etc., indicated that several
genes were involved with ratios disturbed by linkages and lethal genes. Other
characters of staminodes, leaves, stems, fruits, seeds were studied.
In crosses of Canna indica and C. aure.o-viUu.la the proportion of red-margined
leaves in the progeny is said to be influenced by differential growth rates of
pollen tubes of differing genetic constitution, and also by the constitution of
the plasma, so that reciprocal crosses may differ, particularly with respect to
the proportions of plants with red-margined leaves. The appearance of a
giant tvpe as a somatic mutation is recorded.
Cattleya. " (Hurst, 222, 223, 22/,.; Iteychler, /,3H; Beychlcr and Kamerling, 487.)
In crosses of various Cattleya species, rosy purple flower color proved domi-
nant to white, with two complementary genes involved. Certain albinos there-
fore produced colored forms on crossing. Other albinos behaved as monogenic
recessives to colored. The yellow color of Cattleya dowiana var. aurea is reces-
sive to the rosy purple color; yellow color in other cattleyas is partially domi-
nant to rosy purple. Iteychler mentions a collection of 175 seedlings derived
from a cross of two mutants of C. labiata.
Celosia crislata L. (Kanna, 282; Kihara, 800; Terasawa, 507.)
"Mosaic" inflorescence (a mixture of red and yellow) yielded on sclfing a few
reds in addition to the mosaic type. On sclfing these reds a ratio of 3 red:
1 mosaic resulted. Kanna also found red dominant to mosaic. In his mosaic
liucs two types of bud variations were noted. A scries of four multiple allels
governs flower color (yellow or red) and stem color (green or red). Striping
is produced by a recessive gene, which may mutate to the dominant colored
condition.
Centaur -ea cyanus L. (Mekcl, 341.)
A system of three genes is presented to explain inheritance of blue, pink, and
white flower color.
Cheiranthus ckeiri L. (Blaringhem, SO; Nelson, 388; Sirks, /,8I.)
The abnormal form Cheiranthus cheiri var. gynanthus, in which stamens are
replaced by extra carpels and petals are much reduced, is a monogenic recessive
to normal. In flower color dark red and yellowish brown arc independent
monogenic dominants to light yellow; dark red is epistatic to yellowish brown.
The spontaneous appearance of a female plant with stamens aborted is again
recorded by Blaringhem.
Chelidonium majus L. (Dahlgren, 104; Ileijl and Vittion, /,%'; Sax, 467; De
Vries, 528, 529, 580.)
Doubleness is recessive to singleness, but several degrees of doubling appear
in F2. The laciniate leaf type and the "minuV leaf type arc independent
monogenic recessives to the normal leaf type;.
Chrysanthemum. (Miyake and Imai, 362; Shimotomai, 470; Do Vries, 528.)
De Vries found yellow flower color dominant to white in Chrysanthemum
roxburghi. A hybrid, C. marginatum (90 chromosomes) X ('. nwrifolium (54
chromosomes), is highly fertile and appears to be established as a constant
144-chromosome type; C. decaisneanum (74 chromosomes) X C. indicum (36
chromosomes) produced a sterile hybrid. A clone with (lowers variegated white
and magenta, which occasionally produces pure white flowers, is shown to
be a chimera.
Clarkia elegans Douglas. (Batcson, 17; Rasmuson, /,S2.)
Four genes for color are recognized; the order of dominance is purplish red,
salmon red, light red, and white.
Clarkia pulchella Pursh. (Rasmuson, 432; De Vries, 528, 530.)
Three genes for color are recognized; purple is dominant to purplish red;
completely colored flowers are dominant to colored with white margins, and
colored flowers dominant to white.
FLOWERS 987
CUtoria ternatea L. (Rant, 4%4-)
Blue flowers are dominant to white; peloric flowers to nonpeloric.
Coleus. (Correns, 108.)
A variegated form of Coleus hybridus, "albopicta", is influenced by environ-
ment, but probably is inherited as a dominant.
Collinsia. (Hiorth, 207, 209, 210, 211; Rasmuson, 481.)
Hiorth found white-spotted leaves, red-nerved leaves, and white flowers to be
linked in Collinsia bicolor. Later he reported a study of 12 genes in this species,
which fall into five or more linkage groups. The cross C. bicolor X C. bartsiae-
folia produced a nearly sterile Fi, which was further almost sterile on back-
crossing to either parent. Varioup backcrosses and F2 and F3 generations were
nevertheless produced. Two partly fertile tctraploids, larger than the diploids,
were extracted, one from an F2 progeny and one from the progeny derived from
selfing a backcross plant. Rasmuson reports two complementary genes for
flower color in C. bicolor; one of these independently produces a red tinge in
the stems, which is dilute in heterozygous condition. He also finds that the
occurrence of spots on the upper lip of the flower in C. tinctoria is a monogenic
dominant to the lack of spots. Yellow variegated plants in this species are
simple recessives to normal.
Coreopsis tinctoria Nutt. (De Vrics, 528.)
Yellow flowers are dominant to brown (var. brunnea) .
Cosmos bipinnatus Cav. (Miyake, Imai, and Tabuchi, 363, 364.)
A gene for full coloration and a gene for crimson, each acting only in the pres-
ence of a basic gene for color production, are postulated to explain the flower color
classes crimson, pink, shaded, and white. Basal blotch on the ligulatc flowers is
considered to be a monogenic dominant to absence of the blotch. The character
"double ring" of color on corollas is determined by two complementary genes.
The inheritance of pollen color and an abnormal flower type, "bracteoid", have
also been studied. Linkage between two genes has been established.
Cypripedium (and Paphiopedilum) . (Hurst, 2S0, 222, 223, 224.)
Rose purple color is conditioned by two complementary genes; hence
certain pairs of albinos yield colored offspring on crossing. A third gene pro-
duces dilution of color when recessive.
Dahlia variabilis Desf. (Lawrence,. 810, 311, 812.)
The dahlia has been shown to be an octoploid, having eight times the haploid
number of chromosomes, i. e., a gene or its allelomorph may be represented from
one to eight times in a given individual. The yellow arid ivory flower colors
are both dominant to white, yellow showing tetrasomie inheritance, and ivory,
disomic inheritance. Magenta, purple, orange, scarlet, and crimson flower
colors are the result of anthocyanin pigments snowing over yellow and ivory
flavonc ground colors. Anthocyanin color apparently shows tetrasomie
inheritance. Ivory and yellow flavone colors come from different ancestors, and
the chromosomes bearing them do not pair. Similarly the two anthocyanin
color genes occur in two different quadrivalent sets of chromosomes. Lawrence
has also studied inheritance of a recessive albino flower type which is unstable,
producing frequent somatic variation.
Delphinium ajacis L. (Demerec, 110.)
Demercc studied inheritance of two unstable (mutable) genes, rosa-alpha and
lavender-alpha, which frequently revert to their normal allels.
Delphinium orientate Lose. (Beckman, 4%-)
One dwarf type (nana) is a simple monogenic recessive to normal. A second
dwarf (nanella) is also recessive, but shows irregular segregation. Double
flowers are monogenically recessive to sin glc. The abnormal "ranuncula-flower' '
type of double is dominant to the common double. Five genes for color arc
postulated to explain the inheritance of corolla color. The wild color (red-violet)
is dominant over all other colors. A case of linkage is reported.
Dendrobium. (Hurst, 228, 224.)
Purple flower color is dependent on two complementary genes. Certain
albinos yield colored forms on crossing.
Dianthus tarbalus L. (Lilienfeld, 824, 825.)
In some varieties the flower color may change during the lifetime of the flower.
When crossed with normal types this condition was found to be dominant.
Singles X doubles give singles in Fi, and a ratio of 3 singles to 1 double in
F2. Normal growth is also a monogenic dominant to dwarf. At present three
linkage groups have been established.
988 YEARBOOK, 1937
DianihuK caryophyllus L. (Batchclor, 15; Connors, 81; Saunders, 458.)
White flowers are dominant to yellow, and red yellow flowers to red. A
monogenic difference exists between the bullhead type (extremely double) and
the single type; the commercial standard double is the heterozygous form.
Digitalis gloxiniaeflora Hort. (Warren, 584-)
Nonpeloric is dominant to peloric, purple to while corolla color, and purple
spotting on the corolla to brown spotting.
Digitalis purpurea L. (Haaso-Bessoll, 158, 159; Kceble, Pellcw, and Jones, 290;
Miyake and Imai, 350; Saunders, 452, /,59; Shull, 475.)
Conflicting reports exist as to inheritance of some characters. These may be
due to differences in the actual varieties studied. White flower color has been
reported both as a dominant and as a recessive. Some foxglove plants have the
topmost flower of a distinctly different type, which is called peloric This
condition is reported as a simple monogenic recessive to normal. It is also
reported as very complex in inheritance.
Digitalis species hybrids. Buxton and Dark, 65; Buxton and Darlington, 66,
67; Hill, 205; Michaelis, 346.)
According to Hill, reciprocal V\ hybrids of Digitalis purpurea and D. lalea
are unlike, and in each case the hybrid resembles the maternal parent in size
of calyx and corolla. Michaelis also found the l'\ progeny from D. purpurea
(56 chromosomes) X D. lulea (96 chromosomes) unlike the reciprocal. The
Fj chromosome number was 76 in the somatic cells. D. mcrtonensis (112
chromosomes), a fertile totraploid giant, arose from a cross of the two diploid
species D. purpurea and I), amhigua (56 chromosomes in each). It forms only
sterile hybrids with other species, both diploid and tetraploiil. Various hybrid
combinations of diploid species are also sterile.
Dolichos lablab L. (Harland, 194.)
The climbing habit behaves as a monogenic dominant to (he bush habit.
Flower color, seed-coat color, and plant color arc closely correlated. In the
F2 of a cross between two white-flowered varieties, flower color segregated 9
purple: 7 white, and one of the white classes showed intermediate seed and stem
coloration. Two genes are assumed: one determines purplish-brown seed coat
and purplish hairs on the stipules, the other is epistatic to the first and produces,
together with it, purple flowers, black seed, and colored nodes.
Dracocephalum ihyrmiflorum L. (Dahlgren, 107.)
The variety pallida (with white flowers, green plants) is a monogenic recessive
to the typica form (with blue flowers and anthocyanin in the plant).
Epilobium anguslijolium L. (Corrcns, 82, 88.)
The white-flowered variety is a monogenic recessive to the rod-flowered type.
Epilobium hirsutum L. (Przyborowski, 418; Stomps, 495.)
An abnormal type, "cruciata", is a" monogenic recessive to normal. A
monogenic difference was found between two types of spines on pollen grains.
Epilobium species hybrids. (Lehmann, 819, 320, 321; Lehmann and Schwcmmlc,
322; Michaelis, 345, 347, 348, 349.)
Hybrids of most species of Epilobium other than Epilobium parvi.Jl.orum and
E. hirsutum are reciprocally alike, but crosses involving the species mentioned
yield reciprocally unlike hybrids. Differences between the reciprocals arc found
in size of organs, including flower size, in pollen fertility, and in reaction to
mildew. The role of cytoplasmic inheritance in these differences has been
intensively studied. A giant form twice the normal size but with a diploid
complement is described (322).
Eschscholtzia mexicana Greene. (Uphof, 525.)
White flower color is a monogenic dominant to yellow, and white to orange.
Orange self-color is dominant to orange base on yellow petals.
Euphorbia pulcherrima Willd. (Robinson and Darrow, 439.)
The pink form of the poinscttia is a chimeral sport from the red. White is
apparently a mutation from red.
Freesia. (Morgan, 376.)
Several unusual types appearing from spontaneous hybridization are de-
scribed.
Galeopsis. (Hammarlund, 193; Muntzing, 380, 381, 382, 388, 384)
In Galeopsis tetrahit, immunity to mildew (Erysiphe labialanum) is a mono-
genic recessive to susceptibility; heterozygous forms show partial resistance.
Muntzing has studied crossability, cytology, and genetics of species and 80
biotypes. Three groups of species do not intercross: Lwlanum, pubescens-
FLOWERS 939
speciosa, letrahit-bifida. Five species hybrids within the subgenus Ladanum
were produced. A triploid that appeared in the Fj of a cross G. pubescens X
speciosa gave rise to a tetraploid on crossing with G. pubescens as pollen parent.
This tetraploid agrees closely with G. tetrahit in appearance and in cytological
and breeding behavior. Spontaneous G. tetrahit is believed to have arisen from
the above species in a similar manner. On intercrossing pure lines of 6'.
tetrahit, 14 combinations gave high fertility in Fi, and 6 showed partial sterility.
Partial sterility is attributed to a lethal gene, wdiich destroys all pollen grains,
but only part "of the ovules containing it. In G. tetrahit and G. bifida, inher-
itance of flower and stem color and rate of sterility have also been analyzed
genetically.
Gardenia floriila L. (Capinpin, 68.)
Incomplete data on inheritance of doubleness and fertility were obtained.
Geranium robertianum L. (Dahlgren, 107.)
White llower color, "leucanthum", is a monogenic recessive to red.
Geum. (Dahlgren, 107; Marsden-Joncs, 833; Rosen, 448; Weiss and Rosen, 53,9.)
The inheritance of certain characters has been studied in hybrids involving
Geum species. The presence of anthocyanin is a monogenic dominant to its
absence. Large flowers were dominant to small and the F2 segregation indicated
the presence of several genes. Yellow was a monogenic dominant to nonycllow,
and red was dominant to nonred. The experimental hybrid Geum urbanum X
G. rivale is indistinguishable from the naturally occurring G. intermedium; the
reciprocal cross was not successful. Inheritance in G. intermedium is often
irregular.
Godelia amoena Lilja. (Rasmuson 429, 433.)
Each of two types of petal spots, on crossing with unspotted Godetia whitnet/i,
proved a monogenic dominant to the unspotted condition. When intercrossed
the Fi showed both types of spot; in F2, 1 "basal Heck" : 2 double spot : 1
"querfleck" appeared. Rasmuson suggests the two genes arc closely linked.
Double flowers are dominant to single, but degree of doubleness is influenced by
the petal-spot genes mentioned above.
Godelia whitneyi T. Moore. (Rasmuson, J,29, 433.)
Crosses involving different flower colors showed the following monogenic
dominants: White over yellow'-margined white, rod over lilac, rose lilac over
lilac, red-spotted over lilac, red over red-spotted, large spot over small spot, and
light-margined red over pure red. Single flowers arc more or less completely
dominant over double ones.
Helichrysum braclealum Andr. (Dambckalns, 109.)
Three genes affecting white and yellow involucre color arc established.
Sulphur and orange arc simple dominants to recessive white; the two dominants
together condition gold. The third gene, dominant white, inhibits expression
of sulphur, orange, and gold.
Hibiscus rosa-sinensis L. (Mendiola, 84®, 348.)
Lobing of seedling leaves was found to be a monogenic dominant to entire
leaves. Self-sterility appeared to be correlated with absence of lobing. Single
flowers appearing on normally double plants were self-sterile; on crossing with
normal singles they bred like doubles. The occurrence of flower color sports is
recorded.
Hibiscus sabdariffa L. (Howrard and Howard, 218.)
Eight genes are assumed for color in corolla, calyx, pollen, stem, and leaves.
One gene may affect several parts of the plant, e. g., a gene for red in corolla
eye, pollen, leaves, and stem is a monogenic dominant to its absence.
Hyacinthus. (De Mol, 372.)
Hyacinth bulbs X-rayed during flower formation may show somatic variations
in flower, leaf, or pollen characters. Somatic variation in flower color on a
single flower stalk may be the result of mutations induced by changes in environ-
mental conditions during flower formation.
Impatiens balsamina L. (Bedell, 44; Hagiwara, 177; Kanna, 280, 281, 284, 2S5;
Rasmuson, 425, 432.)
At least three genes for flower color are known. White is recessive to blue-
red, and to blue. A dominant gene for intensification of flower color is also
reported. In color patterns, white flecking on colored flowers is reported by
one investigator as a simple dominant to nonficcking; another reported it as a
recessive. There are two types of double flowers, the common and the "camel-
lia", which latter is correlated with a dwarfish stature. Single is a monogenic
990 YEARBOOK, 1937
dominant to common double; but the cross single X camellia gave in F2, 9 single:
3 common double: 4 camellia double. In a recent study (by Kanna) 16 genes are
recognized, 3 lying in each of 2 linkage groups, the others showing largely inde-
pendent inheritance. Ten genes are concerned with flower color, 3 with flower
type. Winged flowers, poloric double flowers, and 3 defective types — "white
blotched", "deficient", and "fasciated" — are all simple recessives to normal.
A nonheritable type of fasciation also occurs. Striped flowers are determined
by a mutable gene.
Tpomoea hederacea Jacq. (Pharbitis nil). (Hagiwara, 161, 162, 163, 164, 165, 166,
167, 168, 169, 170, 171, 172, 17S, 174, 175, 176, 178, 179, 180, 181, 182, 183, 184,
185, 186, 187, 188, 189; Imai, 233, 234, 285, 236, 237, 238, 239, 240, 241, 242,
243, 244, H5, 246, 247, 248, 249, 250, 251, 252, 258, 254, 255, 256, 257, 258, 259,
260, 261, 262, 263, 264, 265, 266, 267; Imai and Kanna, 268, 269; Imai and
Tabuchi, 270, 271, 272; Miyake and Imai, 351, 354, 858, 859, 860, 861;
Miyazawa, 365, 366, 867, 369, 870, 371; S6 and Nishimura, 490; U, 520; Yama-
guchi, 556, 557; Yasui, 562, 563.)
In the Japanese morning-glory white flower is a monogenic dominant to
colored. At least six different white types exist. Some white X white crosses
give colored in F1; and a 9 : 7 ratio of colored to white in P2. A complex inter-
action of complementary genes gives various white types in combination with
a variety of different colored tubes, stems, and seeds. Genes modifying color
have also been studied. The color of the inside of the tube seems to bo con-
trolled by a complex interaction of genes. The inheritance of various types of
corollas has been studied, and the action of complementary and inhibiting
genes reported. Five abnormal flower types were all monogenic recessives to
the normal. Five types of doubleness have also been found to be simple
recessives to normal. At least 17 abnormal loaf tvpes are also simple recessives
to normal. The literature of Ipomoea (Pharbitis) is more extensive than that
of any other plant discussed here, due to intensive studies of a number of
Japanese workers with fundamental objectives. Summary papers now appear-
ing indicate that cultivated forms have arisen mainly through recessive muta-
tions from the prototype; of the 111 genes described, only 15 are dominant;
70 genes have been located in 12 linkage groups (there are 15 pairs of chromo-
somes) ; 21 genes are concerned with flower color; 20 genes affect form of the
leaf; 10 chlorophyll defects showing genie inheritance and 4 showing plastid
inheritance are recognized; 20 genes of low stability (mutable genes) have been
described; a provisional map of 1 chromosome showing linkage intensity, and
many calculations of crossing over between specific gene pairs have appeared.
Ipomoea imperialis. (Correns, 98.)
Two chlorophyll deficiencies, "chlorina" (pale green) and "albomarmorata"
(white spotted), proved to be independent recessives to normal green.
Ipomoea purpurea (L.) Roth. (Barker, 12; Imai, 234, 247.)
Inheritance of flower color is controlled by interaction of several genes.
Flaking of petals is a dominant character. Flower color and stem color are
intimately related. Flower doubleness was found to be a monogenic dominant
over singleness.
Iris. (Bliss, 63: Colin and Carles, 78; Reed, 435; Simonet, 479.)
Observations on color in bearded iris show Mendelian inheritance of brown-
tipped beard, and colored leaf bases. Simonet reports four species-hybrids
not yet of flowering size. Colin and Carles find that only species having the
same glucosidal reserve can be crossed. Reed has described an F2 population
of a cross between Irisfulva and /. foliosa, obtained by selfing the garden variety
Dorothea K. Williamson, a hybrid between these two species. The F3 progeny
showed a great range of color including tvpes with pure yellow flowers.
Lamium. (Correns, 101; Muntzing, 878, 385; Sirks, 482, 485.)
A peloric flowered form of Lamium album was recessive to the normal, but
the F2 ratio indicated five or more genes were involved. Another type with
protruding stamens was also recessive, differing from normal by four" or more
genes. Yellow pollen in L. hjbridum proved to be a monogenic recessive to
red pollen. A type with the lower lips of the flower reduced behaved as a
monogenic recessive to normal in L. maculatum. A cleistogamous flower type
in L. amplexicaule showed a simple factor difference from open-flowered, with
no dominance. In some species the summer annual habit (surviving onlv
by seed) and the winter annual habit (surviving vegetatively) are modifiable";
in L. purpureum an obligate winter annual typo was found to differ geno-
FLOWERS 991
typically from the facultative winter annual. Inheritance of flower color, time
of bloom, height, and vigor were also studied.
Lathyrua odoratus L. (Bateson, 17; Bateson and Punnett, 20, 21, 22; Bateson
and Saunders, 23; Bateson, Saunders, and Punnett, 24; Bateson, Saunders,
Punnett, and Hurst, 25; Gregory, 146; Punnett, 41 4, 415, 416, 418, 419, 420;
Stone, 496; Thoday and Thoday, 508.
In flower color the following mongenic differences were found, dominant
genes being given first: White v. cream, colored v. white, purple v. red, bright
v. dull color, full v. dilute color, light v. dark wings, purple v. copper, purple v.
maroon. Two identical appearing whites give a purple Fi, and nine purple to
. seven whites in F2. A gene for bright color, one for full color, one for light
wings, and one for purple act as modifiers for both purples and reds. Other
color patterns, as marbling and flaking, are either recessive or heterozygous
and not fixable. The four types of growth habit are tall, bush, cupid, and
bush-cupid. Cupid X bush gives the normal tall. A form with sterile anthers
is a simple recessive to normal. Punnett summarized the data on inheritance
in sweet pea in 1924. More recently (1932) he has described five linkage groups
and two unassociated genes in Lathyrus, corresponding to the seven pairs of
chromosomes. Stone reported a somatic mutation from the cupid type to nor-
mal tall.
Lilium. (Griffiths, 151; Heinricher, 198; Preston, 410.)
In a cross Lilium sp. X L. croceum, presence of bulbils was recessive to their
absence. In F2 segregation, parental and hybrid types appeared. In L.
bulbiferum X L. sp. (tigrinum ?), bulbils again proved recessive. Griffiths and
Preston have listed successful species-crosses.
Linaria. (Correns, 91, 95; East, 116; Saunders, 453; Sirks, 484.)
Pink flower color in Linaria is recessive to blue; orange color in the palate
is recessive to its absence. Red X white-flowered L. moroccana yielded blue
in Fi; in F2, nine blue: three red: four white. Orange color in the palate is
dominant to its absence in L. vulgaris. Data on inheritance of sterility col-
lected by Correns have been explained by Sirks according to the scheme applied
to Nicotiana, Veronica, etc. East reports cross-compatibility of 18 species or
varieties of Linaria. Purple flowers are dominant to white, and trailing habit
to bushy, in L. cymbalaria. Copper-colored flecks in the corolla arc dominant
to nonflecked in L. broiisso7inelli X perezi. Four genes are concerned in de-
velopment of flower color in crosses of L. sapphirina, L. moroccana, and L.
reticulata.
Linum species other than L. usitalissimum. (Correns, 99; Hobusch, 212;
Laibach, 307, 308; Tammes, 503.)
In Linum perenne and L. austriacum the long-styled type is a monogenic
recessive; the short-styled type is heterozygous. Self-fertility is apparently
dominant to self-sterility. Several grades of self -fertility occur. In L. austri-
acum the difference between long and short style appears to be governed by
more than one gene. Tammes has summarized the genetics of Linum up to
1928. Hobusch was able to grow the Fi of L. austriacum X L. perenne by cul-
turirjg the normally nonviable seeds on artificial media while still immature.
Studies of backcrosses and later generations indicated that the proportion of
good seeds is determined by degree of relationship of the parent lines.
Lobelia. (Saunders, 465.)
An extensive series of flower types from singles through scmidoubles to full
doubles with five perianth whorls and no stamens occurs in Lobelia. Full
doubles arc sterile, singles arc pure-breeding, but genie analysis of scmidoubles
is not complete.
Lunaria annua L. (Correns, 89.)
The white-margined leaf type, "albomarginata", is a mongenic recessive to
normal.
Lupinus angustifolius L. (Fruwirth, 138; Hallqvist, 192; Kajanus, 276; Roemer,
440, 44.I; Sypniewski, 502; Vestergaard, 526, 527.)
In flower color, monogenic differences were found between blue and white,
blue and red, and red and white. Some crosses between red and white, how-
ever, gave a blue Fi, and nine blues : three reds : four whites in F2.
Lupinus species other than L. angustifolius. (Burlingamc, 63; Kajanus, '276;
277.)
In Lupinus luleus the black-seeded type is a monogenic dominant to gray.
In L. mutabilis blue flowers proved monogenically dominant to white. Work-
992 YEARBOOK, 193 7
ing with L. apricus var. vallicola, L. pipersmithi, and L. nanus, Burlingame
found a white-striped flower type, which segregated into dark blue, white-
striped, and white. This was interpreted on a single gene basis, the white
striped being the heterozygous type. Light-blue flowers were mongenieally
dominant to dark-blue. Dark seeds are associated with dark-blue flowers
but probably not determined by the same gene.
Lychnis (including Melandrium and Viscaria). (Akerlund, 2; Batoson and
Saunders, 23; Baur, 30; Correns, 85; Shull, 473, 474, 476, 477, 478; Tjebbcs,
512; De Vries, 628 530; Winge, 548, 649.)
Lychnis species are normally dioecious, having the male and female flowers
on separate plants. Much of the genetic literature concerns the technical
problem of sex inheritance. Constant-breeding hermaphrodites are main-
tained by a system of balanced lethals. Purple flowers are dominant to white.
Broad leaf is a monogenic dominant to narrow leaf; it is also apparently
sex-linked. Chlorophyll deficient types are recessive to normal green. Winge
(549) reports that "aurea", a chlorophyll defective, is a sex-linked recessive,
restricted to male plants because it is lethal where homozygous. "Variegated",
another chlorophyll defect, is limited to female plants. Akerlund found Melan-
drium album more winter hardy than M. rubrum, the Ft intermediate. Back-
crosses to M. album were more hardy when the hybrid was the pollen parent
than in the reciprocal backcross. Tjebbes recognized four recessive types —
"broom growth", "rolled corolla", "transparent corolla", and "biennial tvpe",
isolated from inbreeding garden strains of Viscaria (Lychnis).
Lythrum salicaria L. (Barlow, 13, 14; East, 112, 113, 114, 115; Ubisch, 521,
o2o. )
The styles of this species occur in three different length classes. Genetic
investigation has been largely concerned with inheritance of style length. A
two-factor hypothesis failed to account for certain midstyle types, and a
balanced lethal hypothesis at present seems most tenable (East, 116).
Malope trifida Cav. (Rasmuson, 416.)
A white-flowered type proved to bo a monogenic recessive to red-flowered.
Matthiola incana (L.) R. Br. (Bateson and Saunders, 23, 24, 25; Correns, 83;
Fisher, ISO; Frost I84, 135, 136, 137; Goldschmidt, 144; Kappert, 286; Leslev
and Frost, 323; Muller, 386; Philp and Huskins, 408; Saunders, 451, 454, 155,
456, 457, 460, 461, 463, 464; Snow, 4S8, 489; Tschermak, 518, 519; Wadding-
ton, 531; Winge, 550.)
A cross of rose X white gave a purple Fi and a trigenic segregation of 27
pale purple : 9 deep purple : 9 rose : 3 deep red : 16 white in F2. There are also
genes that dilute the colors. Two genes are necessary for the production of
anthocyanin; if one or both are absent, the flower is uneolored. There is also
a gene converting all reds to purple, and another causing the difference between
the pure and dull color. Cream is due to pigment in the plastids. It behaves
as a monogenic recessive to white. Doubleness is recessive to singleness (for
discussion of this question, see section on double-flowering stock). Earliness
in blooming is dominant to lateness as is open growth habit to compactness.
Saunders has summarized the published data on breeding of stocks to 1928.
Meconopsis cambrica Vig. (Saunders, 458.)
Doubleness is dominant to singleness, a single gene being involved.
Mimulus. _ (Brozek, 56, 57, 58, 59, 60, 61, 62.)
Inheritance of several characters in Mimulus quinquevulnerus, M. tigrinus,
and M. tigrinoides has been studied. Distribution of color spots over the entire
petal surface behaves as a monogenic dominant to spots limited to half the sur-
face. Single flowers are dominant to doubles, two genes being able to inhibit
the double condition entirely or partly. Plants with a terminal flower differing
from lower flowers showed dominance of this character. Two genes concerned
in flower color have been established in M. cardinalis. One determines develop-
ment of yellow plastids, the other anthocyanin sap color.
Mirabilis jalapa L. (Baur, 28; Correns, 84, 85, 88, 89, 90, 92, 93, 94, 96; Kanna,
283; Kiernan and White, 299; Marryat, 332; Showalter, 471, 472.)
Flower color inheritance in Mirabilis shows manv cases of intermediate
hybrids that cannot be made pure. White X yellow gives pale yellow in Fi and
one white : two pale yellow : one yellow in F2. White X crimson gives deep
magenta, and yellow X crimson, orange red, in a 1 : 2 : 1 F2 ratio in each case.
White X crimson, and white X yellow both give magenta rose in Pi, and a vcrv
complex F2. White X white gave white Fi and F2. In one instance two whites
FLOWERS 993
gave colored Fi types. The striped varieties are all heterozygous, segregating to
self colors and striped in F2. In other characters tall is dominant to half dwarf
and to dwarf. Half dwarf is dominant to dwarf. Kamia and Showalter inde-
pendently interpret flower color expression on the basis of two series of multiple
allels, one series governing base color, the other modifying color expression.
Mutable genes are found in each series. Showalter describes a mutant growth
type, "box", which is a monogenic recessive.
Myosotis. (Chittenden, 71.)
Two genes for flower color are assumed. Pink is dominant to white and blue
is dominant to pink.
Nemesia strumosa Benth. (Riley, 488.)
At least four intrasterile, interfertile lines occur in this self-sterile species.
Nemophila atomaria Fisch. and Mey. (Chittenden, 70.) •
Three genes are postulated to explain inheritance of flower color (lilac, black,
red, pale brown) and four other genes for inheritance of color distribution.
Apparently lilac is dominant to black, black to red, and red to pale brown.
The spotted flower coloration is a monogenic dominant to full-colored.
Nemophila insignis Brand. (Chittenden, 70.)
Blue flower color is dominant to mauve and to white. Mauve X white pro-
duced blue flowers in F,.
Nemophila linijlora Fisch. and Mey. (Chittenden, 70.)
At least three genes for flower color and color distribution are assumed.
Pale-blue flower color is a simple dominant to purplish blue, and spotted eye
(spotted with black) is dominant to full black eye, the two genes showing
independent inheritance. One or two basic genes for flower color are also pos-
tulated. Black spotted leaves are determined by a single gene, the recessive
condition being white spotted leaves.
Nigella damascena L. (Toxopfius, 514-)
Long stems are dominant to the dwarf form. Crosses between yellow varie-
gated and green plants give green in F1( and 3 green to 1 yellow variegated in Fa.
Single flower was a simple monogenic dominant to normal double. A second
double type was dominant to single, and in Fa no single plants appeared. In
studies of color inheritance, colored was dominant to ivory white, blue to violet,
and dark blue to pure white.
Nymphaea. (Anonymous, 1.)
A dominant white is reported.
Odontoglossum. (Hurst, 222.)
Blotched flower is dominant to self-colored, and yellow-flowered to white.
Orchidaceae. (Colman, 79; Godfrey, 14s.)
Two lists of successful orchid hybrids, including intergenic hybrids, have
appeared.
Oxalis corniculata L. (Nohara, 894-)
Purple in leaves and in the eye of the flower is monogcnically dominant to its
absence.
Oxalis rosea Jacq. (Ubisch, 522, 523, 524-)
Two genes for flower color are recognized, one producing light rose when
present in the dominant form, and with a second gene, rose color; white is the
recessive. Three genes for style length are assumed; each of the two genes for
flower color shows linkage with one of these.
Oxalis valdiviana Hort. (Barlow, 13, 14; Ubisch, 524-)
The mechanism of inheritance of style length is, according to Ubisch, similar
to that in Oxalis rosea.
Paeonia. (Saunders, 449.)
Twenty-nine hybrid strains have flowered. An Fa population from the cross
Paeonia albifiora X macrophylla has matured. Two abnormal strains and
a few types of ornamental value have appeared.
Papaver rhoeas L. (Becker, 42; Negodi, 387; Newton, 389; Philp, 406, 407;
Rasmuson, 4S0; Shull, 476.)
A white margin of the petals is dominant to its absence. Seven genes for
flower color have been isolated and belong in three linkage groups. Nine genes
are established by Philp (4p7) . Doubleness is determined by several genes.
Albinism is a simple recessive to normal, and is independent of flower color.
In hybrids of Papaver rhoeas and P. commutatum the characters of the latter
species arc largely dominant.
994 YEARBOOK, 1937
Papaver somniferum L. (De Vries, 528, 530; Fruwirth, 139; Hurst, 221 ; Ishikara,
Kobetsu, and Kojima, 273; Kajanus, 278, 279; Kasaeva, 287; Leake and
Prasad, 313, 314; Miyake and Imai, 353, 355, 356.)
The basal spot on petals is dominant over its absence. Color in the petal is
dominant over white, and purple is dominant over red. When forms arc
heterozygous for color genes they usually produce progenies with considerable
variations in intensity of color. Other color genes have been studied. In plant
size, large is a simple dominant over small, and nonstriped petals over striped.
Other simple dominants are single over double flowers, and laciniated over
entire petals. The cross Papaver somniferum X bracteatum was successful;
the reciprocal produced no viable seeds. The F! plants were perennial, very
variable, including some monstrous forms. F2 plants were obtained.
Pelargonium zonule Willd. (Ballard, 9; Baur, 30; Moncrieff, 373; Noack, 392.
393; Roth, 446.)
Inheritance of doubleness is incompletely analyzed, singleness is regarded
as dominant. A golden-leaved type, "aurea", is "a heterozygous form, segre-
gating on selfing into 1 normal green: 2 "aurea": 1 pure, yellow. The pure
yellow dies in the seedling stage or earlier. The "freak of nature" variety,
the leaves of which have white centers and grecu borders, is not a chimeral
type. This leaf character is inherited through both egg and pollen. The
chemical nature of dominant rose-pink and recessive salmon-pink flower colors,
and of other colors, is interpreted by Moncrieff.
Petunia violacea Lindl. (Ferguson, 126, 127; Frost, 184; Harland and Atteck,
195; Kostoff and Kendall, 302; Malinowski, 888, 829, 330; Malinowski and
Skalinska, 831; Matuda, 340; Moore and Haskins, 375; Rasmuson, 428;
Sachs-Skaliriska, 44®, 486; Saunders, 450, 456; Savelli, 466; Terao, 604; Tcrao
and Nagaharu, 505; Terao and U, 506; Tjebbes, 510, 511; Ubisch, 522; West-
gate, 540; Yasuda, 559, 560.)
Color inheritance was mostly simple monogenic with violet dominant over
red, also over lilac. Uniform coloring is dominant over green-edged flowers.
Violet red X white gave an intermediate Fi, and a 1:2:1 ratio in Fa. Other
colors were more complex. Doubleness exists in a wide range of degree. It is
caused by stamens becoming petals. Singles X singles give all singles, Singles
X doubles give a 1 : 1 ratio. Doubles X doubles give about 3 doubles to 1
single. In Petunia axillaris and P. violacea, the progenitors of the cultivated
petunias, four pairs of genes determine pollen color. The white flower color
of P. axillaris was inherited as a recessive in a cross with a royal purple garden
form, but the parental purple was not recovered in F2. Both P. axillaris and
P. violacea are usually self-sterile, and the Fi is only partly fertile. Garden
forms are sometimes fertile, but several grades of self-sterility also occur.
Harland and Atteck {183) interpret self-sterility on the basis of four multiple
allels. By bud pollination they were able to self four normally self-sterile lines,
finding one homozygous lethal, one dwarfed, the other two normal in appear-
ance. One or more variegated types show irregular inheritance. Mutations
have been induced by X-ray treatment of seed and of flower buds. Some
garden petunias are tetraploid, showing irregular behavior on crossing with
diploid varieties. Petunia pollen has been shown to stimulate fruit formation
in eggplant (Solanum melongena) , but no seeds are formed.
Phacelia. (Chittenden, 70.)
Two species, Phacelia parryi and P. whitlavia were found to cross readily and
furnish fertile offspring. Purple flowers proved dominant to bicolored (purple
limb and white tube), and bicolored dominant to white. A recessive giant type
was found in P. parryi, and a recessive entire-leaved form in P. whitlavia var.
alba.
Phlox drummondii Hook. (Florv, 132; Gilbert, 141: Kellv, 291, 292, 293, 894,
295, 296, 297; Kelly and Wahl, "298.)
Five genes are assumed to account for the inheritance of flower color by
Gilbert {141)- Kelly interprets flower color according to a seven-gene scheme.
Cream-yellow is a monogenic recessive to white. A semidouble type is appar-
ently influenced by more than one gene. Salver-shaped corolla is monogenically
dominant to funnel-shaped. Entire petals are due to one gene; the recessive
form is deeply cut, and the heterozygous form is the "fimbriata" type. Style-
lessness and fasciation are each monogenic recossives to normal. Attempts to
cross Phlox paniculata with P. drummondii yielded infertile Fj progeny; P.
divaricata X drummondii produced an Fj that developed a few seeds (132) .
FLOWERS 995
Polemonium. (Correns, 86; Dahlgren, 104, 106; Ostenfeld, 399, 100, 401; Dc
Vries, 528, SSO.)
Blue corolla color in Polemonium caeruleum is monogenically dominant to
white, pinnate leaf form to bipiimate, normal petal to small narrow petals, and
normal green leaves to the pale green (chlorina) type. Both the blue and the
white flower colors of P. caeruleum proved dominant to the yellow of P. flavum
in Fi, but these interspecific hybrids were sterile. P. mexieanum X pauci-
fiorum yielded intermediate forms in Fi, with complex segregation in F2 and
later generations, most of the segregates proving fertile. The reciprocal cross
yielded no seed, possibly because P. paucifiorum styles are eight times as long
as those of P. mexieanum. Crosses of P. caeruleum with P. carneum and with
P. fdicinum yielded only sterile plants in Fi.
Portulaca grandiflora Hook. (Blakeslee, 47', Blakeslee and Avery, 49; Enomoto,
118, 119; Ikeno, 228, 229, 2S1, 2S2; Okura, 398; Tjebbes, 609; Yasui, 661.)
Color of floral parts and vegetative parts are correlated with each other.
The interaction of five genes for color has been studied. One special white race
is a dominant white with a recessive lethal effect. Pure whites of this type arc
not produced. When selfed it gives two special whites to one normal white. About
one-fourth of the seeds from selfing special white arc nonviable. Mosaics on
the corolla are heterozygous. A Mendelian analysis has not been made.
Doubleness is a simple dominant to singleness. Dwarf type is a simple reces-
sive to normal. This gene reverts to normal fairly frequently. Dwarf plants
bear normal branches, and vice versa. Ikeno reported that inheritance of
purple-spotted flowers did not conform to Mendelian theory. The species is
normally self-fertile, but Tjebbes found a self-sterile variety within which two
self-sterile but cross-fertile groups occurred. Okura identified as haploids
three dwarf individuals from Fj and F3 generations of a cross. These pro-
duced an occasional normal diploid on being pollinated with normal pollen.
Potentilla. (Miintzing, S79.)
Constancy of biotypes within several species of Potentilla is due to perfect
pscudogamous maternal inheritance. Pollen is not functional, but pollination
of emasculated flowers is necessary for setting of seed.
Primula. (Altenburg, S; Bateson and Gregory, 19; Buxton, 64; Chattaway and
Snow, 69; Chittenden, 70; Correns, 102; Dahlgren, 103; 108; Ernst, 121, 122,
123; Frimmel, 133; Gregory, 147, 148, 149; Gregory, De Winton, and Bateson,
ISO; Heinricher, 199; Huskins, 227; Keeble and Pellew, 288, 289; Marsden-
Joncs and Turrill, 337; Pellew and Durham, 405; Raunkiaer, 484; Sansomc, 447;
Somme, 491; Ubisch, 623; Dc Winton, 551, 552, 553, 554; De Winton and
Haldanc, 563; Zollikofcr, 564.)
According to Frimmel (138), three pigments occur in flower colors of the
garden primrose — anthocyanin, carotin, and anthochlor yellow; 260 color tones
are recognizable. Carotin inheritance is monogenic, anthocyanin is digenic,
with a factor for red and another for blue, the two together developing a blue-
violet; white is recessive. Colors approaching black result from association of
the gene for carotin with the two anthocyanin genes. Heterozj'gotos are ex-
pressed as various color tones. Four forms of the "eye" of the flower in Primula
sinensis are known. Small eye is a monogenic dominant to large eye, and white
eye acts in varying degrees as dominant over both small and large eyes. A
fourth type, large greenish eye, is a monogenic recessive to normal. Two
types of doubleness occur. Each is a monogenic recessive to normal. In
several species of Primula normal forms have short styles with anthers borne
above the stigma, or long styles with anthers at a lower level. These are self-
sterile. Crossover types with long styles and anthers at the higher level and
short styles with anthers at the lower level are infrequent but self-fertile. The
short-style type is a simple dominant to long-style, except in P. horlensis, in
which two genes are assumed. In P. obconica fertility is lower when forms of
like style length are crossed than when unlike lengths are crossed. In P.
hortensis and P. acaulis fertilization of normally incompatible forms was ac-
complished by pollinating stubs after removal of styles. In crosses of P.
juliae with P. acaulis and P. elatior, F2 and backcross data were obtained; short
styles were dominant over long, orange over yellow eye. In P. vulgaris one
recessive gene is responsible for various defects in floral organs. A white-
margined leaf type is recessive in P. malacoides. In P. officinalis a defective
type with five extra pistils and no stamens is a simple recessive. Genetic analy-
sis is most advanced in P. sinensis, in which 25 pairs of genes and 2 sets of
996 YEARBOOK, 1937
multiple allels arc recognized. Fifteen of these genes have been located in
four chromosomes. On selflng P. kewensis, a tctraploid species, and several
types with respect to style length, fertility, greening in the corolla, and double-
ness were obtained, but the parental types were not recovered. Other tetra-
ploid forms which appeared in progenies of diploid P. sinensis, proved less
fertile than the diploids. . Only two of seven genes completely dominant in
the diploid, proved completely dominant in the tetraploid, i. e., when one domi-
nant gene and three recessives were opposed. A technical study of linkage in a
tetraploid has been made.
Quamodit. (Nohara, 395.)
Two flower colors in Quamodit pennata differ by a single gene, without domi-
nance. Stem color may be determined by the same gene. The Fi of Q. coc-
cinea X Q- pennata is intermediate and sterile, although Q. sloteri, a fixed race,
is believed to have arisen from such a cross.
Ranunculus. (Marsden-Jones and Turrill, 334; Ragionieri, 422.)
A double, large-flowered form is reported as the result of selection from
Ranunculus asiaticus. Studies of inheritance of color, sex, and sterility in
R. acris and R. bulbosus have not reached satisfactory analysis.
Reseda odorata L. (Compton, 80.)
Orange-red pollen color appears to be a monogenic dominant to yellow, and
self -compatibility has the same relation to self -in compatibility.
Rhododendron. (Ikeno, 230; Miyazawa, 368.)
In studies within the species Rhododendron indicum {Azalea indica) and in
crosses of this species with R. sinense, single flowers were monogenically domi-
nant to double, self-colored flowers to variegated, and short stamens to long.
The prostrate habit is recessive to upright. Flower size and leaf breadth showed
intermediate conditions in Fi. The hose-in-hose type in R. indicum var.
kaempferi was interpreted as a dominant heterozygous form, the pure recessive
being the normal type. The apetalous form (petals replaced by stamens) is a
similar case but two genes are involved, the apetalous being heterozygous for
both, and the normal type double recessive. "Polypetala" (petals separate
instead of united) is a dominant heterozygous form, showing a single gene
difference from normal.
Rosa. (Erlanson, 120; Godfrey, 143; Hurst, 225, 226.)
Incompatibility and sterility present serious difficulties in rose breeding.
Hurst and Erlanson have shown that extensive polyploid series occur in roses.
Hurst found 377 diploids and 629 polyploids in 1,006 species and forms of Rosa
examined. He considers that five diploid species fundamental to the genus have
given rise to many other species in various polyploid combinations. The hybrid
tea roses are chiefly tetraploids, and triploid forms also appear among garden
hybrids. Pentaploid, hexaploid, and octoploid forms are also found in the genus.
Rudbeckia. (Blakeslee, 48-)
Two forms with yellow 'disks were distinguishable by treatment with potas-
sium hydroxide, one turning black, the other yellow. On crossing these two
yellow types, purple (normal type) appeared in Fi, and in F2, 9 purple : 3
"black-yellow" : 4 "red-yellow."
Salvia. (Bateson, Saunders, Punnett, and Hurst, 25; Blaringhem, 52; Hruby,
219.)
Pink flower color in Salvia horminum is a monogenic dominant to white, while
violet is the result of interaction of the gene for pink with a second complemen-
tary gene which has no effect (i. e., white) when present alone. In the course of
six generations of selfing of S. pratensis (normally hermaphrodite and blue-
flowered), decreased vigor and fertility, and segregation of types with white
flowers, female flowers, mosaic leaves, etc., were observed. Attempts to cross
S. nutans with S. juriscici have thus far failed, but selfing of a supposed natural
hybrid yielded parental types and an intermediate type like Fi.
Saponaria ocymoides L. (Meunissier, S44-)
A large, pink-flowered type was found to be dominant to a small white type
in Fi.
Saxifraga. (Marsden-Jones and Turrill, 335; Whyte, 547.)
Saxifraga potternensis is a tetraploid derivative of the cross S. rosacea X
granulata. Its breeding behavior is uniform.
Senecio vulgaris L. (Trow, 515, 516, 517.)
A scheme of at least 12 genes has been formulated to explain inheritance of a
number of differences existing between various named types of this species.
FLOWERS 997
The characters studied include type and color of heads, incision of rays, color
of stems, color of leaves, number of nodes. Two or more instances of linkage
are recognized.
SUene. (Correns, 91; Marsden-Jones and Turrill, 886, 888; De Vrics, 528, 680.)
Pigmented flowers in Silene armeria are dominant to white. On crossing white
X rose flower color Correns found a monogenic relation, in which white and
rose are pure breeding forms and the hcterozygotc is red. This red type was
like the wild form in appearance, but the latter was found to be a pure-breeding
red. S. vulgaris showed segregation for various characters on selfmg. Segrega-
tion was noted also in the progeny of a cross of this species with S. maritima. A
type with defective petals proved to be a simple recessive to normal.
Sisyrinchium angustifolium Mill. (Miyake and Imai, 852, 857.)
On crossing a self-colored purple with a white with purple eye, a monogenic
relation was found, the self-colored proving to be partially dominant.
Tagetes erecta L. (Punnctt, 417 '.)
The double flower is a monogenic dominant to single, and the flat typo of
floret to the tubular, the two characters showing independent inheritance. Two
or more genes are apparently concerned in the difference between deep orange
and lemon-yellow flower color.
Teiragonolobus purpureus Moench. (Nilsson, 891.)
Yellow flower color is a monogenic recessive to red.
Tropaeolum majus L. (Correns, 98; Eyster and Burpee, 125; Rasimison, 427, 482.)
Monogenic differences were found between dark-yellow and light-yellow
flowers, between red anthocyanin and its absence. Variegated flowers are
dominant to self-colored. The climbing type is a monogenic dominant to the
dwarf type. Dark-green leaf color is determined by two genes. Two defective
types, pale green and white-spotted leaves, each proved to be simple recessives
to normal green and showed independent inheritance. Doubleness and fra-
grance are monogenic recessives. "Super-double" is dominant to both single
and common double.
Tropaeolum species hybrids. (Fischer, 129; Warren, 635.)
On crossing Tropaeolum majus X T. minus, red flower proved dominant to
yellow, green leaf to variegated, and tall stature to dwarf. The gene for stature
was partially linked with that for leaf color. In the hybrid between T. minus
and. T. peregrinum, known as T. pinnatum, red pigment in corolla and stem
proved dominant to its absence, and the relation appeared to be monogenic.
Tulipa. (Hall, 190; De Mol, 872.)
So-called "thieves", narrow-petalcd forms, are probably mutant forms in
tulip varieties. They also occur in tulip bulbs X-rayed during flower formation.
Venidium X Arctotis. (Warren, 586, 587.)
A natural hybrid, Venedium wyleyi X Arctotis stoechadifolia var. grandis, was
largely intermediate between the parents but taller and bulkier. In F» no clear
segregation occurred, but various characters showed dominance of one or the
other parental types.
Verbascum blattaria L. (Shull, 473.)
Bright yellow corolla is a monogenic dominant to pale yellow.
Verbascum phoeniceum L. (Sirks, 480, 483, 484-)
The inheritance of self-compatibility and self-incompatibility in this species
appears to be complex and somewhat irregular.
Verbena. (Eyster, 124.)
Light variegations in flower color arc dominant to heavy variegations; varie-
gation is dominant to dilute self-color; light self-color is dominant to darker
self-color.
Veronica gentianoides Vahl. (Correns, 98, 100.)
The short-styled form is a heterozygous dominant, the long-styled is the
homozygous recessive. Style length is further affected by a series of modifying
genes. A white-margined form, on crossing with the normal, produced only
normal in Fi and F2, the defective type showing no genie inheritance.
Veronica longifolia L. (De Vries, 628, 680.)
The white-flowered type is recessive to the pigmented form, the recessive
occasionally appearing as a somatic mutation in large Fi populations.
Veronica syriaca Roem. and Schult. (Filzer, 128; Lehmann, 81 6, 816, 317, 818.)
Blue flowers are monogenicalty dominant to rose and white. Self-sterility
is determined by a series of multiple allels, which accelerate or inhibit pollen-
998 YEARBOOK, 1937
tube growth in compatible and incompatible styles. In the F2 of a cross, four
intrasterile but interfertile groups appeared.
Veronica tourneforti C. C. Gmel. (Beatus, 41-)
In this tetraploid species, number of sepals (four or five) appears to be deter-
mined by a series of multiple allels.
Viola arvensis Murray. (Clausen, 72.)
Study of inheritance of a spot on the style revealed unusual relations, which
were explained on the assumption of three or more pairs of genes.
Viola tricolor L. (Clausen, 72, 78, 74; Kristofferson, 303, 80G.)
The inheritance of flower color is somewhat complex, indicating gene inter-
actions. The presence of a colored spot on the front of the style is dominant
to its absence. A second type of spot requires the presence of another gene
before it can appear. The prostrate habit of growth in the variety maritima is
dominant to the erect type of other varieties. Some characters, such as varie-
gations, are apparently non-Mendelian. They appear to depend on plastids in
the cytoplasm. The velvety black flower color of Viola tricolor var. nigra is
reported to be determined by three basic genes for expression of color, and five
inhibitor genes, which suppress the development of velvety black.
Viola species hybrids. (Clausen, 75.)
Clausen has reported 25 successful species crosses. Viola tricolor and V.
arvensis cross with many species; V. cornata with only V. orphanoides and V.
elegantula; V. calcarata with only V. battandieri. Some new fertile types have
been isolated from crosses.
Zanledeschia (Richardia). (Ragionieri, 4B1.)
In a cross between Zanledeschia rehmannii and Z. elliottiana most of the char-
acters of the latter proved dominant in Fj, the yellow spathe color being an
exception. In F2 spathe color, size, form, spotting of leaves, etc., showed
segregation, but the number in the progenies were too small for interpretation
of genic relations.
MISCELLANEOUS FORAGE
AND COVER CROP LEGUMES
ROLAND McKEE, Senior Agronomist,
A. J. PIETERS, Principal Agronomist,
Division of Forage Crops and Dis-
eases, Bureau of Plant Industry
A HE large family known as Leguminosae, or legumes, contains
some of the most interesting and important crop plants. The legumes
are distinguished from other plant groups particularly by their
flowers and seed pods. The flowers are always irregular in shape,
resembling a butterfly, while the pods have two valves or parts into
which they readily divide, as in the case of garden beans or peas.
Most of the plants with pods that split into halves are legumes.
Another distinguishing characteristic of legumes is their ability to
take nitrogen directly from the air through association with bacteria
that live on their roots, and to manufacture it into food for plant
growth. By this means soils are enriched, soil fertility is maintained,
and increased crop production is made possible. Some of the minor
legumes used solely for cover crops and soil improvement are not so
well known as crops grown for forage or grain, but they deserve much
wider recognition and could well be used much more extensively.
Improvement work with legumes other than soybeans, alfalfa, and
clovers has been very limited, but the importance of this group of
plants justifies giving them serious consideration in any improvement
program. They have been the subject of some genetic investigation,
which will be discussed later.
BREEDING WORK AND POSSIBILITIES
While the legumes considered in this article occupy a place secondary
to such crops as alfalfa and red clover, some have proved of great
yalue in sections in which the other legumes do not thrive. The
annual lespedezas, for example, because of their ability to grow on
soils of low fertility and too acid for alfalfa and clover,' have become
the chief forage crops from southern Iowa to the Gulf of Mexico.
Without them a profitable agriculture in much of that region would
be difficult or impossible.
Likewise the vetches and field peas fill an irreplaceable function in
the soil-improvement programs of the Southern States, while the
cowpea is a standard crop and the bur-clovers furnish winter grazing
and soil improvement for millions of acres. Of the more recently
introduced crops the crotalarias fill a place on sandy land not otherwise
filled, and there are good reasons for believing that some of these
species may become leading forage crops in the South.
The present soil-conservation program will require legumes for a
variety of situations, but all must have in common the property of
999
1000 YEARBOOK, 193 7
adaptation to reduced fertility and probably to soil acidity. Among
these miscellaneous legumes now little known there may bo some that
with proper attention to selection will prove precisely suited for one
or more such situations.
Astragalus
(Astragalus spp.)
The genus Astragalus contains a very large number of species,
commonly called milk vetches. Most of them are especially adapted
to dry and arid conditions. None of the species is of much commercial
importance, although several are utilized locally and have forage
value. No selection or other improvement work has been attempted
in this genus, but the drought-resistant quality of the many species
would seem to justify the conclusion that for dry-land and arid regions
it is perhaps the most likely group from which to expect a legume of
agricultural value.
Beggarweed
(Meibomia spp.)
The beggarweed or tick trefoil group is composed of a fairly large
number of species, few of which have been brought under cultivation.
The Florida beggarweed {Meibomia purpurea (Mill.) Vail) is the best
known and the only one that is grown commercially in the United
States. No attempt at improvement has been undertaken, although
some natural selection no doubt has taken place, as the crop is har-
vested from cultivated stands. To what extent improvement is
possible no one can say. The species are variable, however, and, no
doubt, would respond readily to selection. One botanical variety,
M. paniculata var. pubens (T. and G.) Vail, that has been grown in
experimental plantings has growth habits that give promise of
usefulness.
WHILE the legumes considered in this article occupy a place
secondary to such crops as alfalfa and red clover, some have proved
of great value in sections in which other legumes do not thrive.
The annual lespedezas, for example, grow on acid soils of low
fertility, and without them a profitable agriculture in large areas
from southern Iowa to the Gulf of Mexico would be difficult or im-
possible. The vetches and field peas likewise fulfill a valuable
function in soil-improvement programs. Among the miscellaneous
legumes about which comparatively little is now known, many-
forms especially suited to thrive in difficult situations could un-
doubtedly be found by intensive study and developed by systematic
breeding.
MISCELLANEOUS FORAGE LEGUMES 1001
BONA> 1ST
(Dolichm lahhh L.)
The bonavist, which in habits, cultural requirements, and uses is
much like the cowpca, has been used in Africa and southern Asia from
ancient times, ami many varieties are known to exist. Nowhere has
improvement of the crop been attempted, although improvement
with reference to nematode and wilt resistance and other character-
istics no doubt could he effected (fig. 1).
Figure I. — Bonavist (Doliclius lublub) showing general habit of growth.
Bur-Clover
(Afedicago spp.)
Many species of Medieago that never are grown as cultivated crops
enter into use for pasturage and are recognized as having very great
value for this purpose. However, these have received no attention
from the plant breeder. Other species that are grown for soil improve-
ment and occasionally used for bay or seed have received some
attention by experimenters. In a few instances selections of distinct
forms have been made by practical growers who have increased their
supply of seed and distributed it locally. Natural selection resulting
from regional climatic differences, however, is responsible for much of
the improvement in (he medicagos.
In the case of spotted bur-clover (Medieago arabica (L.) All.) at
least two new forms have appeared in the South in recent years.
One of these, Manganese bur-clover, was selected and named by A.
1 38S04 "— o7 04
1002
YEARBOOK, 1937
Lee Andrews on his place at Lafayette in eastern Alabama. The
other, Early Southern bur-clover, was selected and named by A. F.
Ruff at Rock Hill, S. C. Both these varieties are earlier maturing
than the commercial spotted bur-clover from which they were selected,
and make as good a growth, if not better. A variety of bur-clover
grown by H. H. Hopson in Coahoma County, Miss., under the name
Giant bur-clover seems to be identical with the Early Southern and
probably has the same origin. The Manganese bur-clover is somewhat
earlier than the Early Southern and matures about 2 weeks ahead of the
•
Figure 2. — Coiled seed pods of spiny and spineless forms of spotted bur-clover
(Medicago arabica). In other species variation in length of spines is not
uncommon.
commercial spotted bur-clover. A spineless form of spotted bur-clover
has been recognized as a subspecies, but this has never been grown
commercially (fig. 2).
California bur-clover (Medicago hispida Gaertn.) is very variable
and responds to improvement by selection. Where bur-clovers occur
spontaneously it is difficult to maintain pure stands of selected forms,
and in pastures all that can be hoped for is to increase the relative
amount of the improved varieties. Improved selections of bur-clovers
were made by the United States Department of Agricidture some years
ago and distributed from the United States Plant Introduction Gar-
den at Chico, Calif., but supplies of seed have not been maintained
and none are available commercially. The Texas Agricultural Experi-
ment Station has made selections of the California bur-clover and is
increasing seed of spineless forms for use in sheep pastures. The
many other species are quite variable, like the species just mentioned,
and could be readily improved by selection, but so far as is known most
of these are in no way superior to the species now used commercially.
Thus there seems to be no reason to give them special attention in
MISCELLANEOUS FORAGE LEGUMES 1003
preference to the commercial forms. Black medic (Medicago lupulina
L.) is quite variable and could be improved readily by selection. No
work lias been reported on the improvement of this plant.
ClIICKI'JJA
(Clear arieiinuia L.)
Throughout the western United States attempts have been made
to grow the chickpea, which is native to western Asia, but nowhere
has commercial production been successfully established. So far as
known, no attempt has been made to develop superior varieties
adapted to the United States, although it is known that the chickpea
is variable and thus presumably could be improved by selection.
Com I'liA
(Vigna sinensis (Tomer) Savi)
A very large number of cowpea varieties are recognized. For the
most part those have been developed through several hundred years
by natural hybridization and incidental selection rather than by any
planned improvement program. Introductions into the United States
arc recorded in the seventeenth century, but it is within the last century
that specific reference is made to named varieties. In the United States
in recent years considerable work has been done by experiment stations
in the way of bringing existing varieties together for comparative test-
ing. This has resulted in a more extensive use of superior varieties
and an elimination of inferior ones. While selection of superior plants
has thus been the principal means of improving cpwpeas, natural
hybridization has played a very important part. Artificial hybridiza-
tion in recent years has been attempted by a few plant breeders, and
at least one outstanding variety has been developed in this way.
A cross between the Groit and Brabham varieties made by workers
in the Department of Agriculture resulted in the Victor, character-
ized by its resistance to wilt and nematodes, which seriously damage
most varieties. In the process of continuous growing and natural
selection through long periods of tunc, varieties have changed to suit
local conditions with reference to diseases, insects, and climate.
Apparently for this reason varieties that have been grown for years
in the United States are much more resistant to bean rust than re-
cently introduced varieties, and resistance to wilt and nematode in
the Iron, Brabham, Groit, and New Era varieties can be attributed
to similar selection. In the case of the Victor, resistance to wilt and
nematode has been inherited from its parents, the Brabham and Groit.
The origin of most of the commercial varieties of cowpeas is un-
known. The Whippoorwill has been grown under that name since
1840, and the Iron has been known in South Carolina since 1888, but
its origin is uncertain, and no information is available as to whore
the New Era may have come from. From a study of the characters
of the Brabham it has been concluded that it is a hybrid between
Iron and Whippoorwill, and the Groit is regarded as a hybrid of New
Era and Whippoorwill. Improved selections from Brabham and
Iron have been made in California and are being grown commercially.
Recently a variety of unknown origin was introduced into Florida
1001
YEARBOOK, 1937
and distributed to growers by tbe State Agricultural Experiment
Station, under tbe name Suwanee. It bas given higb forage yields
and seems to be especially well adapted to Florida conditions.
Ckotalaria
(Crotalaria spp.)
Crotalaria, commonly called rattlebox, is one of the newest agri-
cultural crops that has become of commercial importance in the
United States within the last 10 years. In India and a few other
figure 3. — Crotalaria s[>ectabilis, V. C. 18096 (a), and the commercial strain
from which it was selected (6).
tropical regions several species have been in use for a much longer
period. Three species are now grown commercially in the United
States. These are Crotalaria spedabilis Roth, C. striata DC, and
C. intermedia Kotschy. Being variable in plant characters, they lend
themselves readily to improvement by selection. Late maturity,
which makes the saving of a good seed crop difficult, has been one of
the principal objections to crotalaria, and this character was the first
in which improvement was attempted. The Department of Agri-
culture and the North Carolina, South Carolina, Georgia, and Florida
Agricultural Experiment Stations working in cooperation have made
selections for earliness in all of these species. At Columbia, S. C,
an early-maturing variety of C. spedabilis has been developed that
ripens its seed quite uniformly and 2 weeks or more ahead of the
original lot from which it was selected. This is known as F. C. 18096
and in South Carolina has been called locally Carolina crotalaria
(fig. 3). Some progress has been made in selecting early varieties
MISCELLANEOUS FORAGE LEGUMES 1005
of C. intermedia and C. striata, but additional improvement is needed
before these can be called, superior.
Since most of the Crotalaria species have been observed only in the
wild, it is not possible to say how much improvement may be ex-
pected. Up to this time, however, little work has been attempted.
Fenugreek
{Trigonclla focnumgraeewn L.)
Fenugreek (the name means Greek bay) occurs in the Mediterranean
region and east as far as India. As grown under cultivation it shows
varietal differences that probably are the result of natural regional
development rather than artificial selection. So far as known no
special improvement work has been done in any country. In the
United States fenugreek has succeeded only in California, and there it
is grown only occasionally. At the California Agricultural Experi-
ment Station at Davis the continued propagation for years of one of
the best introduced strains of fenugreek appears to have resulted in the
development of a superior variety well suited to at least that part of
the State.
Field Pea
(Pisum arvense L.)
The history of the field pea is closely associated with that of the
garden pea, since the distinction between the two groups is more one
of xisage than of botanical characteristics. The more extended use of
varieties of field peas, however, has been in comparatively recent
times, while the use of the garden pea extends back to earliest history.
The development of pea varieties through all these years has been
largely the work of the gardener and the commercial seed grower,
while the field husbandman has merely grown the varieties apparently
best suited to his conditions.
In more recent times a number of experiment stations have made
selections from the more promising varieties and introduced them.
The experiment stations in Canada and in the United States, particu-
larly in "Wisconsin, Colorado, Idaho, and Washington, have been most
active in this work. The varieties O. A. C. 121, Wisconsin Perfection,
and others represent the results of such work.
The new interest in field pea varieties has been largely in connection
with their use as a cover and green-manure crop for the South. The
Austrian Winter variety serves well for this purpose, but its suscepti-
bility to disease and its inability to mature a good seed crop under
southern conditions has lessened its popularity and called attention
to the need for breeding and selection to overcome these difficulties.
The Department in cooperation with the Georgia Experiment Station
has recently inaugurated a program with such results as the objective.
The State experiment stations at Auburn, Ala., and Knoxville, Tenn.,
have begun similar programs.
By bunging varieties together from every possible source and grow-
ing them under southern conditions it is probable that varieties with
superior disease resistance and heavy seeding qualities will be found.
These can then be used in a breeding program to combine the other
desirable qualities needed in a cover and green-manure crop.
1006 YEARBOOK, 1937
Grass Pea
(Lathyrus sativus L.)
Lathy rus sativus, commonly known as grass pea, has never become
of commercial importance in any part of the United States, although
in many places it makes good growth and produces fair seed crops.
In India the crop is of some importance, the natives using the seed for
food and the plant for forage. A large number of varieties exist,
differing in flower and seed color, growth of the plant, and size and
shape of the seed. Varieties with large white seeds are superior for
human food, while those with strong vegetative growth are preferred
for fodder. Varieties of L. sativus occurring in India have been
studied by Howard and Khan {11)} While inheritance studies have
been carried on with the sweet pea (L. odoratus L.), no one has studied
L. sativus or related species in this way.
Guar
(Cyamopsis psoraloides DC.)
Guar, a summer annual, is used in India quite commonly for food
for man and beast. Varieties exist, and the plants are more or less
variable, but so far as known no special work on improvement has been
attempted. In the United States guar has been used in cultural
experiments but has not been recognized as having commercial value.
KlDNEYVETCH
(Anthyllis vulneraria L.)
No commercial plantings of kidneyvetch are made in the United
States, and so far as known no selection or other improvement work
has been attempted in this country. In Wales, selection work with
this plant is in progress, but results have not yet been published. In
Denmark the improvement of kidneyvetch has been attempted, and
strains Tystofte No. 8 and Tystofte No. 28 when compared with com-
mercial kidneyvetch were found to be more productive.
Kudzu-Bean
(Pueraria thunbergiana (Sicb. and Zucc.) Benlh.)
No work has been done in the improvement of kudzu-bean, but
there is no reason to suspect that it would not respond readily to
improvement by selection.
Lespedeza
(Lespedeza spp.)
The lespedezas or bush clovers as a group are still wild plants. Only
one species, Lespedeza striata (Thunb.) H. and A., has been long known
to agriculture. The others are of such recent introduction that the
possibilities of improvement have not been adequately explored.
Agronomically there are two groups of lespedezas. The annual
consists of two species, Lespedeza striata, or common lespedeza, and
L. stipulacea Maxim., or Korean lespedeza. The second and much
larger group consists of perennial plants, of which one species only, L.
sericea (Thunb.) Benth., has recently been introduced to agriculture.
• Italic numbers in parentheses refer to Literature Cited, p. 1018.
MISCELLANEOUS FORAGE LEGUMES 1007
As is the case with, most wild plants, the lespedezas are more or less
variable, plants differing in size of leaflets and height of growth, in
habit, and especially in date of maturity.
Lespedeza striata, common lespedeza, was first found in Georgia in
1846, spread rapidly over the lower South, and gradually worked
north. The character that made this spread possible was undoubtedly
the difference in date of maturity between plants. As the species
worked farther north the earliest forms seeded and reproduced them-
selves. This process went on generation after generation, until now
the common lespedeza is established as far north as central Indiana.
The variations in habit of growth were made the basis of selection
work by the late S. H. Essary, of the Tennessee Agricultural Experi-
ment Station. He began his study of individual plants in 1912 and
found a great variation, especially in the habit of growth. Among the
variants was one having an erect habit and great productive capacity,
which was segregated and put into experimental plantings in 1921.
This was introduced by the Tennessee station as Tennessee 70 and is
one of the leading late-maturing varieties.
Another variety with larger leaflets and ranker growth than usual was
found by J. B. S. Norton, an explorer of the Department of Agriculture,
growing wild near the city of Kobe, Japan, and was introduced as Kobe.
It is somewhat earlier in maturity than Tennessee 76 but does not grow
so erect except in thick stands. Another variety of common lespedeza,
inventoried as no. 81742, was collected by Dorsett and Morse, of the
Department, in Japan in 1929 and is the earliest maturing form of
Lespedeza striata. In habit it is nearly as erect as Tennessee 76.
The. possibilities for improvement in this species have not been
exhausted, but its natural dependence on high temperatures will
probably prohibit pushing the species much farther north than its
present limits.
The Korean lespedeza also shows variations, especially in date of
maturity. Two extra-early forms have been found growing wild in
Manchuria. One of these, no. 65280, has been introduced as Harbin;
the other, no. 59379, is a week later and makes a little larger growth
than Harbin. Neither variety promises much usefulness, because the
plant is low in growth habit and the yield is consequently small. They
do, however, show the range of possibilities in the development of
earliness. Harbin has matured seed at Winnipeg.
Two varieties, an early Korean, no. 19604, maturing about 2 weeks
earlier than standard Korean, and a late form, no. 19601, maturing 2
weeks later than the standard Korean, have been selected at the
Department nursery at the Arlington Experiment Farm, Arlington,
Va. (fig. 4). The early form, no. 19604, has been released for use in
northern Iowa, northern Illinois, and adjacent areas. Its habit of
growth and yielding ability are like that of standard Korean, and it
differs only in earliness. The late form, which is matting in growth
habit, is still under observation.
Here again the possibilities of selection have not been fully explored,
and in the future better varieties, or varieties better suited to certain
conditions, may be selected.
The group to which Lespedeza sericea, the perennial lespedeza,
belongs consists of several species differing from one another in
1008 YEARBOOK, 1937
botanical characters and in habit of growth. Certain variations in
L. sericea itself have been noted. The botanical group consists of
L. sericea, an erect, rather strict plant with narrow leaflets; L.
inschanica (Maxim.) Schindler, with larger leaflets and lax habit;
L. latissima Nakai, a prostrate plant; and L. juncea, intermediate in
habit between L. sericea and L. latissima. Variations in L. sericea
are found in width of leaflets, height of growth, coarseness and number
JH*
2m?*
^^^r-i^w
A*s*j*
*JM mkm: V
Figure 4. — Korean lespedeza (Lespedeza slipulacea). Selected plants showing differ-
ent growth habits. The plant on the left (a), with horizontal lower branches,
makes a low matting growth, while 6 is quite upright.
of stems, and earliness (fig. 5). Of the varieties studied, no. 04730 is
early, tall, and coarse, no. 12087 is later, with finer stems, and no.
19284 is from a single plant selection out of no. 04730 and is somewhat
more uniform than the pareut. These variations are neither im-
portant nor significant, but they show that a more intensive study may
uncover variations of agricultural significance.
One of the most important fields for selection with Lespedeza
sericea is that of finding forms with a low tannin content. Studies
made show that the tannin content varies among individuals, ranging
from about 5 or 6 to 10 or 11 percent. From the standpoint of
palatability as well as forage value, it is important that a form with
low tannin content be found and introduced. Work with this object
is being carried on.
The shrubby species, as Lespedeza bicolor Turcz. and its allies, have
not been studied intensively enough to determine the range of varia-
tion, and it does not seem probable at this time that they will offer
great possibilities for agricultural usefulness.
Lotus
(Lotus spp.)
Several species of Lotus (not to be confused with the water-lily of
that name) are recognized as being of some commercial importance
in several European countries and in Australia, but in the United
MISCELLANEOUS FORAGE LEGUMES 1009
States none is recognized as having special value. Seed of Lotus
cormculatus L. and L. uliginosus Schkuhr, two perennial species that
are used for hay and pasturage, is available through the seed trade,
but no varieties are listed. So far as known no special improvement
of these plants has ever been attempted, although varieties with low
cyanophonc glucoside content have been reported. The elimination
Figure 5. Lespedeza sericea, showing variation in size and habit of growth. Plants
in each row are from seed of a single mother plant.
of this glucoside is desirable, since in the course of digestion it is
changed to hydrocyanic acid, which is injurious to animals.
Lupine
(Lupinus spp.)
Several species of Lupinus are grown commercially as field crops
in European^ countries, and at least one species is being used in
Australia. None, however, has ever been commercialized in the
United States, since experimental plantings have indicated that in
most places they are not well adapted and cannot be used as economi-
cally as legumes now commonly grown.
Varietal improvement in this group of plants has been confined
largely to work in European countries, particularly Germany and the
Union of Soviet Socialist Republics, where in recent years attempts
have been made to produce lupines devoid of alkaloid poisons. Both
German and Russian workers report having developed strains with
little or no alkaloid, winch they call "sweet lupines." The object
1010 YEARBOOK, 1937
has been to produce plants and seed that could be used for both
livestock and human consumption without injurious results.
Peanut
(Arachis hypogaea L.)
The improvement of the peanut for forage has received little
attention. In the United States the experiment stations of Florida
and Texas have undertaken hybridization studies, but the results of
this work have not yet been published. Arachis nambyquare Hoebne
and A. rasiiero A. Cheval. have been used in crossing with the common
peanut (A. hypogaea), and attempts have been made to introduce
other wild species. These offer possibilities but as yet are too little
known to justify a statement regarding results.
PiGEONPEA
(Cajanus indicus Spreng.)
In many tropical countries the pigeonpea is recognized as one of
the most valuable legumes. In India a large number of varieties
exist and the superior value of some of these is recognized. In the
Hawaiian Islands, where the pigeonpea was introduced, improvement
of the crop has been undertaken and selection and breeding work
have resulted in the production of superior varieties. New Era
strain X is recognized in Hawaii as one of the most desirable and
much superior to the strains from which it was produced. In the
United States varieties have been grown for selection work at several
southern stations. The plantings at the Florida Agricultural Experi-
ment Station at Gainesville have been the most extensive. Wide
variation in the plants has been observed and early-maturing varieties
have been selected, but no variety has been found sufficiently well
adapted to justify commercial use. One variety has matured as far
north as Washington, D. C, but seed production has been light.
Sainfoin
(Onobrychis vulgaris Hill.)
Sainfoin has been grown in France and other European countries
for over 300 years. In the United States it has never become of com-
mercial importance, although in experimental trials at a number of
experiment stations it has made good growth. A number of botanical
varieties are known to exist, but improvement of most of these for
agricultural use so far as known has never been attempted. Com-
mercial sainfoin is quite variable and includes both biennial and per-
ennial forms. Improvement by selection in both of these no doubt
could be easily effected. The Washington Agricultural Experiment
Station at Pullman is making selections of sainfoin with the idea of
obtaining better adapted varieties.
Skrhahella
(Ornkhopus sativus Urot.)
In central Europe serradella is used on acid sandy soils, but in the
United States production or use on a commercial scale has never
been successful. Improvement of varieties is reported from Germany,
although the amount of work seems to have been very limited.
MISCELLANEOUS FORAGE LEGUMES 1011
Sesbania
(Sesbania macrocarpa Muhl.)
The seed of sesbania as found in the commercial trade is gathered
from wild and volunteer plants and represents the species as it is
found growing naturally. The plant grows in wet or moist soils in the
Southern States. No attempts at impz'ovement have been made.
Sulla
{Hedysarum coronarium L.)
Attempts to grow sulla in the United States have indicated that
while it succeeds fairly well in a number of places so far as growth is
concerned, it does not appear to have a place in competition with
legumes now commonly grown. In several European countries it is
grown as a commercial crop and is considered as having superior value
for special localities. While varieties are known to exist, few attempts
at varietal improvement seem ever to have been undertaken. In
New South Wales a special strain was selected for many years and
tested on the experimental farms, but for other countries no work is
reported.
Velvetbean
(Stizolobium spp.)
The Florida velvetbean (Stizolobium dseringianum Bort) is one of
the leading legume crops in the southeastern United States. It was
introduced in Florida previous to 1875 and for many years was con-
fined largely to that State, since it would seldom mature much farther
north. Attempts to grow the crop in Georgia and Alabama later
resulted in the selection of mutants that required a much shorter
season to mature and were well adapted otherwise. In 1906 Clyde
Chapman, of Sumner, Ca., observed an early-maturing plant that he
selected and grew under the name Hundred Day Speckled. This
variety later became known as Georgia and is the earliest maturing
commercial variety now grown.
In 1908 R. W. Miller, of Broxton, Ga., selected an early-maturing
variety that was grown as Clark's velvetbean, but this proved to be
so like the selection made by Chapman that it later was considered
identical with the Georgia.
In 1911 a Mr. Blount, of Flomaton, Ala., selected an early-maturing
variety, which he called Alabama. This was not quite so early ma-
turing as the Georgia but was sufficiently good to become commercial-
ized and is still being grown.
A variety of velvetbean known as the bush velvetbean (fig. 6)
was selected on the farm of Roan Beaseley at Kite, Ga., about 1914.
As its name implies, it is a bush or bunch variety, lacking the twining
habit of other velvetbean varieties. In work with this variety at the
Mississippi branch experiment station at McNeill, H. R. Reed noted
a white-seeded variant and made selections of it with the idea of using
the white seed character to identify the bush variety. This selection
did not prove to be stable as to seed color, and subsequent selection
was continued. Now after 10 years a variety seems to have been
obtained that reproduces true to color.
1012
YEARBOOK, 1937
At the Florida station a hybrid variety known as Osceola was pro-
duced by John Belling, who made a cross between the Florida velvet-
bean (Stizolobium deeringianum) and the Lyon velvetbean (S. niveum
(Roxb.) Kuntze). This is a vigorous, heavy-yielding variety with a
medium season, so that it is adapted as far north as central Georgia.
Jigure 6. — Bush velvetbean.
The velvetbean offers opportunity for much further improvement,
and the importance of the crop suggests that such work could be done
with profit.
Vetch
(Vicia spp.)
A large number of species of Vicia are in general use, all of which
go under the general name vetch. The species that are of importance
commercially are Vicia villosa Roth, V. sativa L., and V. pannonica
Crantz. Others that are occasionally used are V. atropurpurea Desf.,
V. calcaraia Desf., V. monantha Desf., V. dasycarpa Ten., and V.
angustijolia Grufberg. So far as known, vetches are close-pollinated,
and seldom, if ever, does crossing take place. All species seem to be
variable, but differ somewhat in this respect. Hairy vetch (V. villosa)
is much more uniform than common vetch (V. sativa), and while
several species seem to be less variable than hairy vetch, none are so
uniform but that improvement can be made by selection.
Common vetch has been grown in the Mediterranean region for
centuries, and through regional selection and otherwise a large number
of varieties have been developed, differing in seed color and growth
MISCELLANEOUS FORAGE LEGUMES 1013
characteristics. Much, of the improvement in this crop, no doubt,
traces to selections made by local growers, but natural selection due
to continued regional production probably also played a part. In
later years experiment stations have developed improved varieties for
local use, but published statements regarding such work are very
meager.
Most of the work in vetch improvement in the United States has
been carried on at Corvallis, Oreg., by cooperation between the
Department and the Oregon station.
In this region common vetch has been grown for many years, and
the commercial strain now grown is the result of natural selection
through this long period. The winter temperatures of western
Oregon and western Washington represent about the extreme of cold
that the most hardy strain of common vetch will endure. Thus the
variety that has survived and been developed and increased here in
commercial production represents one of the most winter-hardy of
the common vetches.
Since other vetches are of very recent introduction commercially,
natural selection has played little if any part in the development
of varieties.
In the case of both hairy vetch and common vetch the work of the
Oregon station, cooperating with the Department, has resulted in
improved varieties that already have been or are becoming commer-
cialized. Here a vigorous growing variety of smooth vetch (V.
villosa var.), lacking the heavy pubescence of hairy vetch, was selected
in 1926 by H. A. Schoth and is now grown quite extensively. A good
deal of the seed of V. villosa imported from central Europe under the
name hairy vetch is smooth vetch and resembles the smooth Aretch
variety grown in Oregon. Of the common vetch {V. sativa) selections
that have been developed, a white-flowered variety, F. C. 02830, that
is somewhat superior in vigor and winter hardiness to commercial
Oregon common vetch and was selected by Sohoth in 1915, is perhaps
outstanding. The white-flower character offers a ready means of
identification in the field and will enable the grower to keep his
seed pure.
In the Netherlands, Denmark, and other European countries where
common vetch is grown, improved varieties adapted to local conditions
have been developed, but none of these, so far as they have been
tested in the United States, has proved superior to varieties developed
in this country.
GENETIC STUDIES IN MISCELLANEOUS LEGUMES2
Inheritance studies have been made in few of the so-called miscel-
laneous forage legumes. From general observation and in some cases
from definite experimental demonstrations it is known that a number
of legumes are self-pollinated and rarely if ever are cross-fertilized.
Whether or not these can be crossed or hybridized has in many cases
not been determined.
Studies of several species of Phaseolus in India indicate that the
urd bean (P. mungo L.) and the mung bean (P. aureus Roxb.) are
3 This section is written primarily for students or others professional! v interested in breeding or genetics.
1014 YEARBOOK, 1937
usually self-pollinated, although the mode of anthesis in many cases
would permit of cross-pollination.
Unpublished observation of legume plantings in the United States
indicates that Crotalaria, Vicia, Latkyrus, and the annual species of
Medicago are largely self-pollinated and seldom if ever cross-fertilize.
A close study of anthesis in such cases, however, might indicate a
means of effecting crossing.
No work on crossing lespedezas has been done. The technical
difficulties are of the same order as those presented by the clovers
and are due to the fact that the flowers are small and difficult to
manipulate. There is another difficulty in addition. The three com-
monly known species of Lespedeza — L. striata (Thunb.) H. and A.,
L. stipulacea Maxim., and X. sericea (Thunb.) Ben th.— have flowers
of two kinds, and both kinds occur in the same cluster. One set of
flowers bears a corolla and is therefore conspicuous; the other and
more numerous kind has closed flowers with reproductive parts com-
plete but with no corolla. These flowers are consequently self-fertile.
Although definite data are wanting, the conclusion drawn from
observation is that these species are self-fertile. No sign of hybridiz-
ing has been observed, though the species have been grown side by
side for years. The progeny from the seed of individual plants is
always true to the mother plant.
In the case, of serradella, which has been reported as self -fertile,
plants inbred for four generations did not lose vigor.
While crossing in many legumes seems to be uncommon, there are
others that cross readily and are naturally cross-fertilized. Species
that have been used in inheritance studies are the cowpca (Vigna
sinensis (Torner) Savi), chickpea (Cicer arietinum L.), adzuki bean
(Phaseolus angularis (Willd.) Wight), bonavist (Dolichos lablab L.),
horsebean {Vicia jaba L.), pigeonpea (Cajanus indicus Spreng.), lupine
(Lupinus spp.), peanut (Arachis hypogaea L.), velvetbean (Stisolo-
bium deeringianum Bort), and field pea (Pisum arvense L.).
Chickpea
{Cicer arietinum L.)
While self-pollination is the general rule in Cicer arietinum, varietal
crosses have been recorded. In 1915 Howard, Howard, and Khan (10)
reported the growing of selections that split in the F2 generation,
indicating natural crossing. Their observations were not made in
sufficient detail, however, for the deduction of the various color factors
present.
More recently inheritance studies were made by Khan and Akhtar
(IS) relating to color and number of flowers. In making artificial
hybrids it was found that in order to prevent accidental crossing
emasculation should be effected the evening of the second day pre-
ceding fertilization. The flowers open naturally on bright days be-
tween 9 and 10 a. m., and the pollen should be applied at this time.
Five crosses were studied and the following results reported (IS, p. 155):
(1) The flower color depends upon the interaction of several factors.
(2) Blue color depends on a single factor B.
(3) Pink color is produced by a factor P in the presence of B.
MISCELLANEOUS FORAGE LEGUMES 1015
(4) In the absence of B the flower is white whether P is present or absent.
(5) Greenness in the standard is developed in the absence of the factor W.
Greenness is therefore recessive to nongrecn.
(6) Singleness depends upon a factor S and is dominant to doubleness.
COWPEA
(Viffia sinensis (Torncr) Savi)
The cowpea has boon recognized as one of the legumes that offer
excellent facilities for inheritance studies, and investigations by
Spillman and Sando, and in particular by S. C. Harland, have indi-
cated what may be expected by more extended research. In studies
made by Spillman and Sando (16) flower color was found to be corre-
lated with coloration in the seed coat, joints, peduncles, stipules, and
petioles, and complete linkage was observed in certain seed-coat-color
factors.
It was determined that the presence of anthocyanin coloration in
the stem and leafstalk is due to a single unit factor, dominant to its
absence.
■In the case of certain sccd-coat-color patterns, two factors that are
inherited independently were found to influence the color pattern,
resulting in the expected 9:3: : 3:1 ratio.
Seventeen Mendelizing factors of cowpeas were definitely identified.
These factors with the characteristic effect they produce are as follows:
A. Seed pod curved after the manner of the alfalfa seed pod.
B. Brown seed coat.
D. Dense speckling, characteristic of the New Era variety.
E. Narrow eye.
F. Very fine and dense speckling, giving rise to blue seed coat.
0. Dotting; converts Holstein spots into numerous small ones.
II. Holstein type of seed-coat spotting.
/. Eye with indefinite margin.
L. Longitudinal furrowing of the surface of the seed.
A7. Presence of anthocyanin pigment factor.
P. Purple seed coat.
B. Red seed coat. (This is the general factor for color, the absence of which
determines white seed coat, white flowers, and absence of pigment in
vegetative parts.)
S. Black spotting on certain types of seed coat.
T. Less dense speckling, characteristic of the Taylor variety.
U. Buff, or clay-colored, seed coat.
W. Whippoorwill type of seed-coat spotting.
X. Taylor inhibitor cancels (crosses out) the effect of T.
The eight factors B, F, N, P, It, TF, V, and X, either singly or in combination,
give rise to the ten distinguishable seed-coat colors, purple, black, dull black, blue,
coffee, maroon, buff, red, pink, and white. The factors P, B, D, T, and F and
probably 8 belong to a linked group. The factors D, T, and F restrict the dis-
tribution of color pigments in the seed coat. Three independent eye factors /,
II, and E, either singly or in combination, give rise to the five distinct types of
eyes, Watson, Holstein, small eye, narrow eye, and very small eye.
Indications were found that when all of the pigment factors are absent, including
factor /?, there is a tendency for the seeds to be small, weak, or abortive.
The flower color has been found to be correlated with the coloration in the seed
coat, joints, peduncles, stipules, and petioles (16, pp. 282-283).
Experiments reported by Haigh and Lochrie (6) indicate a progres-
sive variation with age of a simple Mendelian ratio in the cowpea.
The results in the F2 cultures from successive days of flowering
showed an orderly variation in the simple Mendelian 3:1 ratio, an
1016 YEARBOOK, 1937
excess of recessives in the first 9 days being compensated for by an
excess of dominants as the plants grew older. No cause for this
phenomenon was discovered.
Hofmann (9), in experiments at the University of Illinois, found that
crosses made in the greenhouse between California Blackeye and
Blue Goose show definite evidence of hybrid vigor.
BONAVIST
(Dolichos lablab L.)
In studying Dolichos lablab, Harland (8) found that dehiscence of
the anthers takes place at least 1 and sometimes 2 days before the
flowers open. Studies in inheritance showed that in the case of deter-
minate and indeterminate growth the segregating ratio in the F2 gener-
ation was 3:1, with complete dominance of the indeterminate factor.
Two factors were found to influence color, each being transmitted
independently, resulting in the expected 9 : 7 ratio. One of these
factors has no effect except in the presence of the other, when it
converts white flower into purple, and brown seed into black, and
causes pigmentation of the nodal region.
Lupine
{Lupinus spp.)
Burlingame (2) reports studies of Lupinus species with reference to
variation and inheritance. His findings show that races with, dark-
blue and pink flowers breed true and that races with striped white
flowers are heterozygous for a single factor, which in the homozygous
condition produces white flowers. Light-blue flowers are due to a
single dominant factor, indistinguishable in the homozygous and
heterozygous condition.
Dark seed coats are linked with dark-blue flower color, but probably due to
separate factors.
The factors for light-blue and striped-white flowers are both allelomorphic to
that for dark-blue and not improbably constitute a system of multiple allelo-
morphs.
Mutations are frequent, some are already known to be dominant, and others
appear to be in the nature of additions of new characters and factors and so
progressive in the sense of de Vries (#, p. 4-Jfi) .
Hallqvist (7) studied seven different types of flower color and five
types of seed color in Lupinus angustijolius L. His conclusions were
as follows (7, p. 844):
One fundamental colour factor has been demonstrated (pure red) . A synthesis
of blue colour has been obtained from crosses between bluish red and violet flower
colours. One "dilution" factor has been found to be present.
Pleiotropic correlation has been demonstrated between certain flower and seed
colours.
Three flower colour factors have been found to form a linkage group. The
linkage between two of the factors is very close, if not complete. The other
linkage value represents a crossover percentage of about 22%.
Greb (5), in studying Lupinus albus L., found that there are at
least two genetically different rootlet types in this species. These
differ in rate of rootlet elongation in young seedlings and in time of
development of the root hairs. The ratio in the F2 was 2:1, which
suggested that the homozygous nonhairy might be lethal.
MISCELLANEOUS FORAGE LEGUMES 1017
Adzuki Bean
(Phaseolus angularis (Willd.) Wight)
Kakizaki {12), in a study of crosses between Miyako and Donsu
varieties of adzuki bean, found that reddish purple in the stems, black
spotting on red seed coats, and blackish brown in ripe pods were
dominant over their recessive allelomorphs, green stems, unspotted
seed, and brown pods. From the segregating ratios in the F2 it was
concluded that color of stem was due to the interaction of two factors,
while the black spotting of the seed coat and color of ripe pods were
influenced by only one factor pair.
Colored stems are completely correlated with black-spotted seed
coats, and colorless (green) stems with unspotted seed coats.
The factor P for reddish-purple color of stems and its recessive allelomorph p
(green stems) are very closely linked with S, a factor for black-spotting of sccd-
coats, and its recessive allelomorph s, respectively, and hardly any crossing over
occurs between them.
The I factor, which intensifies the purple color of the stem, and its recessive
allelomorph i are also very closely linked with the B factor, which produces a
blackish-brown color of the ripe pods, and b, its recessive allelomorph, and this
linkage is also very close, so that crossing over hardly ever occurs between them.
The PS linkage group is independent of the I-B linkage group.
Presence of S in a homozygous condition produces more intense spotting of the
seed coats than when it is present in a heterozygous condition {12, p. 177).
HORSEBEAN
(Viciajaba L.)
The horsobean is known to cross readily but has been used com-
paratively little in inheritance studies. Darlington (8) studied varie-
gation and albinism and found that variegation is a heterozygous typo
of which albino and normal are the homozygous types. Sirks (15)
in a study of quantitative inheritance in Viciajaba presented evidence
to indicate that quantitative factors do exist.
Velvetbean
{Slizolobium spp.)
Several species of Stizolobium have been hybridized. _ Inheritance
studies made at the Florida Agricultural Experiment Station a number
of years ago were reported in the annual reports of that station for
1910, 1912, 1913, and 1915. Species that have been hybridized are
S. deeringianum Bort X S. paehylobium Piper and Tracy, S. deeringi-
anum X S. niveum, and S. deeringianum X S. hasjoo.
The inheritance studies are concerned mostly with the cross 8.
deeringianum X S. niveum, which are the species of most economic
significance. In these crosses Belling (1) found that color in wings
and standard, length of seed, curve in pods, and open and closed pods
were influenced by a single factor pair, and. size of pod and length of
pubescence on pod. by two or more factors, while mottling was due to
three independent factors. Correlations were established between
lateness of flowering and number of flowers in a raceme and between
length of pod and seed.
l:!S004°— 37 05 ++
1018 YEARBOOK, 1937
PlGEONPEA
(Cajanus indicus Spreng.)
Inheritance studies with the pigeonpea carried on at the Hawaiian
Agricultural Experiment Station have been reported by Krauss
(14, P- IS). According to his findings —
* * * red flower standards are dominant over yellow; blotched or speckled
seed dominate over solid colored, and maroon-blotched pods are dominant over
solid light-tinted pods. Pubescent pods are dominant over glabrous; large, flat
pods are dominant over small round pods, and large seeds over small seeds.
Four and five seeded pods arc dominant over 3 and 4 seeded pods. Round seeds,
slightly flattened, dominate over all others of widely different shapes, including
spherical, oval, flattened, and irregular. The axillary flowers and pods domi-
nate over terminal inflorescence. Instature blended inheritance is observable, very
dwarf varieties when crossed with very tall varieties produce an intermediate
type, and two varieties when crossed almost invariably produce a type that is
taller and more vigorous than either parent. Crossing an annual type on a per-
ennial type appears to produce perennial forms. This behavior has been found
to remain constant, practically complete dominance for some well-defined differ-
entiating unit characters being the rule.
When red dorsal standard sorts were crossed with rod types, it was noticed that
the solid red changed to red lacing, and when extremely tall and dwarfed forms
were crossed, the first generation was of intermediate height. Wherever domi-
nance is apparent the second generation shows fairly definite Mendelian segregation
as well as definite linkage between some characters. Dihybrid crosses appear to
adhere rather closely to the 9 : 3 : : 3 : 1 ratio.
Studies in Cajanus indicus relating the inheritance of color in the
flower and seed coat have been reported by Dave (4)- lu most cases
one factor pair controlled color inheritance, but in others two inde-
pendently inherited factors were operative, in agreement with the
general results obtained by Kraus. Complete linkage was noted
between orange-yellow flowers and purplish-black seed, yellow
flowers and back of standard with purple veins, and base diffused
purple and green pods; and purple color at the back of the standard
was closely linked with maroon color of the pod.
LITERATURE CITED
(1) Belling, J.
1911. SECOND GENERATION OP THE CROSS BETWEEN VELVET AND LYON
beans. Fla. Agr. Kxpt. Sta. Rept. 1911: lxxii-civ, illus.
(2) BURLINGAME, L. L.
1921. variation and heredity in M7WNTJS. Amer. Nat. 55: 427-448,
illus.
(3) Darlington, D. C.
1929. VARIEGATION AND ALBINISM IN VICIA FAIiA. Jour. Genetics 21:
[161]-168, illus.
(4) Dave, B. B.
1934. inheritance of characteks in cajanus indicus. Indian Jour.
Agr. Sci. 4: 674-691, illus.
(5) Greb, R. J.
1935. two genetically different rootlet types in the lupine. Jour.
Heredity 26: 503-504, illus.
(6) Haigh, J. C, and Lochrie, J. V.
1929. investigation of a mendelian ratio in vigna sinensis by a
consideration of the progeny from successive daily
crosses. Ann. Bot. [London] 43: [783J-803.
(7) Hallqvist, C.
1921. THE INHERITANCE OF THE FLOWER COLOUR AND THE SEED COLOUR
in lupinus angustifolius. Hereditas 2: [299]-363, illus.
MISCELLANEOUS FORAGE LEGUMES
1019
(8) Ha BLAND, S. C.
1920. INHERITANCE IN DOLICHOS LABLAB., L., PART I. J()Ur. Genetics 10:
219-226.
(9) HOFMANN, P. W.
1926. hybrid vigor in cow peas. Jour. Heredity, 17: 209-211, illus.
(10) Howard, A., Howard, G. L. C, and Khan, A. R.
1915. SOME VARIETIES OF INDIAN GRAM (CICER ARIETJNUM L.). India
Dept. Agr. Mem., Bot. Scr. 7: 213-235, illus.
(11) Howard, G. L. C., and Khan, A. R.
1928. THE INDIAN TYPES OF LATHYRUS SATIVUS L. (KHESARI, LAKH,
lang, teora). Indian Dept. Agr. Mem., Bot. Scr. 15: 51-77,
illus.
(12) Kakizaki, Y.
1923. LINKED INHERITANCE OF CERTAIN CHARACTERS IN THE ADZUKI BEAN.
Genetics 8: [168]-177.
(13) Khan, A. R., and Akhtar, A. R.
1934. THE INHERITANCE OF PETAL COLOUR IN GRAM (CICER ARIETINU.M I,.).
Agr. and Livestock in India 4: 127-155, illus.
(14) Krauss, V. G.
1932. THE PIGEON PEA (CAJANUS INDICUS), ITS IMPROVEMENT, CULTURE,
and utilization in Hawaii. Hawaii Agr. JOxpt. Sta. Bull. 64,
46 pp., illus.
(15) Sirks, M. J.
1929. .GROWTH AND INHERITANCE OF LEAF DIMENSIONS IN THE BROAD-
BEAN (vicia faba l.). K. Akad. Wetensch. Amsterdam, Proc.
Sec. Sci. 32: 1066-1084.
(16) Spillman, W. J., and Sando, W. J.
1930. MENDELIAN FACTORS IN THE COWPEA (VIGNA SPECIES). Mich.
Acad. Sci., Arts, Letters, and Papers 1 1: 249-283, illus.
APPENDIX
Table ] . — Chromosome numbers in legumes
Xanie 1
Acacia arabka Willd
A. baikyana F. Muell _ __. __
A, cyanophylla Lindl
A. dealbata Link___ _
A. demrrens Willd _ _.
A. dermalopliylla F. Muoll. [Bcntk.J
A. eburnea Willd
A.farnesiana AVilld
A. horrida Willd.- __
A. longifolia Willd
A. lophantha
A. nilotica
A. podatyriae/olia A. Cunn __ __
A. saligna Wendl _
A. scorpioides A. Ohev., var. adstringens (Schum. and Thon.) A. Chev.
A. scorpioides A. Chev., var. nilotica Bcntli _
A. scorpioides A. Chov., var. pubescens Bentli
Aeschynomene indica L
Amorpha califomica Nutt _
A.fmticosa L.._
Do-
A. microphytla Pursh _
Amphicarpa monoica (L.) Ell_
Anthyllis alpestris Kit __.
A. barba-jovis L
A. genardi L
Chromosome
nura hers 3
J. 'I
20
10
20
2n
±52, ±104
26
26
20
26
±52, ±104
±52, ±104
±52, ±104
26
24
±52, ±104
20
26
52, 104, 208
±52, ±104
±52, ±104
40
12
14
16
RoftTlillCl!
110.
3(«), (18)
(m, eo)
(26, 28)
(26, 28)
(27,18)
(IS)
(27, 28)
(26, 28)
(26, 28)
(27,28)
(74)
(16)
(26, 18)
(27)
(27, 18)
(18)
(27, 28)
(44)
u«;
US:
(48)
(48)
(II)
(7)
(7)
(7)
1 Names are given as in the articles cited except for obvious misspelling. Where the wrong authority
for a name is given it is followed by the correct authority in brackets.
2 Letters following numbers denote number of times verified by other authors. c=l; d=2; e=3; f=4;
g=5; h =6; j =8; k=fl; s=17; t =18.
• Italic numbers in parentheses refer to References for Chromosome Numbers. In the case of more than
1 determination, the earliest author giving the established number is listed.
1020 YEARBOOK, 1937
Table 1. — Chromosome numbers in legumes — Continued
Name
A. maritima Schweigg
A. tetraphylla L
A. vulneraria
Arachis hypogaea L
A. hypogaea (Spanish and small Japan peanuts).
A. nambyguare
A. prostrata Benth. var. rasteiro
A. rasteiro Chevalier (?) . ...
Astragalus alopecurioides L . .
A. altaicus Bunge
A.baeticus Ij
A. candidissimus Led
A. echinus DC ...
A. edulisDur
A. exscapus B. transsilvanicus A. and G. = A. transsilvanicus Barth.
A.falcatus Lam j...
A. galegiformis L
A. hamosus L ...
Do
A. hypoglottis L.
A. massiliensis I/am
. A. membranaceus Fisch. [Bungcl
A. mollis
A. monspessuJanus L _
A. secundus DC * „.
A. sesameus L __ ___ _.
Do.
A. sieversianus Pall.
A. sinicus L
Do.
A. transsilvanicus
A. sulyinus AVilld
Baptisia australis R. Br
B. australis R. Br. var. exalta Sweet .
B. sulphurea Engelm
B. tinctoria R. Br
Biscrrula petecinus L
Cajanus indicus Spreng
Calophaca wolgarica Fiseh
Canavalia ensiformis DC
C. gladiata DC. ...
Caragana arborescens Lam
C.frutescens DC
Carmkhaelia australis R. Br.
Cassia didymobotrya
C. dimidiata— .
C. fistula
C. leschenauliiana DC.
C. mimosoides L.
C. occidenialis L
C. purpurea Roxb
C. sophera L
C. tomentosa L
C.toroL
Cerds siliquastrum
Offer arietinum L
Do
Do.
C. kabulium
Clitoria lernatea L
Colutea arborescens L
C. halevica Lam._
C. media Willd. (.C. arborescens L. X C. orientalis Lam.)_
C. orientalis Lam
Crotalaria alata Ham
C. anagyroides H. B. K
C. arenatia Benth
C.juncea
C. obovala G. Don
C. retusa L
C. usaramoensis Back. [Baker].
C. raletonii Back
Chromosome
numbers
(5
20e
JO
H
8
24
8
11
8
11
15
11
24
,16
13
10
12
12c
13
2n
12
16
12
40c
•10
±40
40
16
16
64
■18
16
16
16
18
22
10c
32
28
10
lie
16
16
16
16
16
"ia"
Reference
no.
(7)
(?)
Oil
(«)
(35, pp.
(37)
(28)
(M)
US)
(4)
(47)
U)
U)
(48)
(4)
(47)
(47)
(48)
(4)
(4)
(48)
U)
(78)
(47)
(fi«)
WO
(4)
(4)
(44)
(74)
(4)
(4?)
(70
(.5)
(7/)
(5)
(47)
(95)
an
Ui)
(7)
(7)
(4)
U»)
(70)
(74)
77, pp. 541-
623.
Ui)
(44)
(56)
(SI)
(44)
(Sfi)
06)
(13)
(17)
(IS)
(55)
(17)
(7)
(4)
(48)
US)
(48)
Ui)
Ui)
(32)
(2)
(S2)
Ui)
(U)
(U)
* Approximately.
MISCELLANEOUS FORAGE LEGUMES
Table 1. — Chromosome numbers in legumes — Continued
1021
Name
Cyamovsis vscraloides DC
Cytisus canariensis O. KuntzR..
C. nigricans L
Do.
C. purpureas _
C. scovarais Link ___ _
C. scouarrus
C. semlifolius L
Desmodium grandiflorum (Walt.) DC.
J>. perpesium DC*
Ponchos biftor us
D.lablabh
Do
Do
D. lubia Forsk
D. multiflorus
D. nitotkus Del
I), ornatus Wall
Dorcynium herbaceum Vill_.
D. hirsutum Ser
D. rectum Ser __
D, suffruticosum Vill
JKrythrina crista-galli L
Galega officinalis L
Do_
G. orientalis Lam
Genista fcrox Poir
<?. pilosa L
(?. sagittalis L
G. fiwctoria v. angustifolia Ledeb..
<?. tfriattjrwJons Kit
Glycine gracilis Skvortzow
G. hispida.
G. hispida Max -
G. soja Sieb. and Zucc
G. soja var. akasaya
G. ussuriensis
Glycyrrhiza aspcra Pall
G. echinata L -
G. uralensis Fisch
Hedysarum elongatum Fisch. var. albiflorum Ledeb-.
Ilymenocarvus circinnatus Savi
Indigofera asvera Perr
7. decora Lindl
7. diphylta
/. gerardiana Wall ..
I. khilovri Maxim
I. parviflora HeyDe
7. pseudotinctoria Malsum
J. pseudotinctoria ..
7. suffruticosa Mill ._.
7. sessilijlom DC
/. viscosa Lam
Laburnum adami
L. alpinum Griseb _.
L. vulgare..
Lathyrus anguletus L_ .
L. annuusXi- __.
L. apham L
L. articulatus L
L. cicera L
L. cirrhosus Ser -_.
Lathyrus clymenum L_.
Do_
L. crampes Gillies
L. dumetorum Philippi
L. ensifolius Bad
L. grandiflorus Sibth. and Sm_.
L. heterophyllus L
L. hirsutus L __
L. tatifotius L
L. macropus Gillies
L. magellanicus Lam
L, maritimus Bigel
X
Chromosome
numbers
24c
11
11
20
200
8
21
8
7c
7c
7c
In
14
4fi
48
24
2-1
24
22
24
22
22
14
14
14
14
44
10
48
21
44(42-45)
48
48(48-50)
40
38
40
40d
38
40
16
Heference
48
48 (EO)
48
14c
14
<.14
14
14
14
14
14
(63)
(6)
(81)
(5)
(73)
Ui)
TO
(S)
at)
Ui)
(S3)
(78)
Ml)
(S3)
(7)
(S8)
(7)
(7)
(7)
(7)
(7)
(7)
(7)
U7)
(4)
(47)
(5)
(»)
(«)
(6)
(S)
m)
(SO)
(«)
(44)
(86)
(7)
(4)
(47)
«)
(66)
(7)
(32)
(4)
(32)
(47)
(44)
(32)
(«)
(74)
Ui)
(S£)
(SB)
(73)
(■5)
(73)
(71)
(71)
(IS)
(14)
(IS)
(59)
(69)
(09)
(71)
Ui)
(71)
(71)
(84)
(69)
(63)
(44)
1 Approximately.
1 Apparently name is wrong.
1022 YEARBOOK, 1937
Table 1. — Chromosome numbers in legumes — Continued
Name
Chromosome
numbers
Reference
L. sphaericus Rctz.
L. tingitanus L
L tuberoms~L
L. venoms Muhl
L. vcrnus Bcmh
Do.
mger ...
nigrivalis A. Burkart _-- -
nissolia L
numidicus Batt
ochroleucus Hook
ochrus DC
odoratus L
palusiris
pannonicus L. [Garcke]
■paranensis A . Burkart
parodii A. Burkart ...
pratensis L. -
pubescent Hook, and Arnot
quadrimarginotus Bory and Chaub-.
rotundifolius Willd ..
sativus L
sessifolius Hook, and Arnot -
seti/olius L
sylvestrisXi
Do..
Iiens esculenta Moeneh..
Do.
Lespedeza bicolor Turcz _
L. cyrtobotrya Miq
L. daurka Schindl
L. homoloba Nakai
L. nericea Bonth
L. sieboldi Miq
L. stipulacea Maxim —
Ii. tormnioua Siebold
L. variegata Cambess _
Lotus angustissimus L
L. cornicutatU8 It ...
L. corniculalus L. var. ttlpestris Lamottc.
L. cornkulatus I/, var. japonicw Hegel---
L. crrtieus L
L. cytisoides L - --
L.filtcaulis Dur __
L. hispidus Dest
L. ornithopodiodes L ..
L. requieni Mauri
L. siiiguosus L
L. tetragonolobus L
L. uliginosus Schkuhr
Lupinus albkoccineus ._
L. aXbus h
Do.
(ingudifolius L
Do
Do
barkeri Lindl
densijiorus Benth
douglasii A.gar
elegansJl. B. and K. T. H
hartwcgii Lindl
hirsutus L. var. micranthus Boiss..
luteutli— -
Do. —
Do
Do
micrahthufi Dougl...
mutabilis Sweet
Do.
Do
nanus Dougl
ornatus Dougl
pilosus Jj. [Murr.]_
polyphyllus Lindl
1 Approximately.
20
24
1.23
21
140
14
14
14
I4d
14
14
14
14
14
14
14
"ii"
28
"lie"
iif"
20
20
18
12
12c
24
28
14
12
24
14
14
14
14
14
48
50
MO
40c
50c
48
48
48
48-50
50
44-45
46
48
42
48
48
48
42
(IS)
(«»)
(71)
(71)
(69)
OS)
(Si)
(6U)
(SS)
(60)
(69)
(S3)
(71)
(69)
(71)
(U)
(71)
(SS)
(71)
(SS)
(21)
(69)
(71)
(68)
(7 Si
(6S)
(ii)
(ii)
(11)
VM
(ii)
(ii)
(ii)
(il)
(U)
(7)
US)
(7)
(ii)
(7)
(7)
(7)
(7)
(7)
(7)
(7)
(7)
(7)
(79)
(79)
(72)
(SB)
(ii)
(61)
(S)
(79)
(79)
(7.9)
(79)
(79)
(78)
(ii)
(SS)
(61)
(79)
(8S)
(Si)
(79)
(79)
(79)
(79)
(11)
MISCELLANEOUS FORAGE LEGUMES 1023
Table 1. — Chromosome numbers in legumes — Continued
Name 1
(
Chromosome
numbers
Reference
i
n
2«
48
48
36
48
(7.9)
(79)
(79)
(7,9)
48
48
16
160
32
16
lfid
IB
16
16
18
16C
(»)
L. venustus Vilm ._
(79)
(29, S8)
M. arabica All- _ ___ __ __
M. arborea L .. _. _ _ -
M. carstiensis Wulf .._. __ ___ _ ... _.
(S3)
(29, SS)
(IS)
019, «)
(&9)
M. denticulate Willd _
(», 2S)
(29, 28)
(11)
M. echinus "DC . ._ ... ..
16
(25, 28)
(78)
J do— ..":/ ": :~~~ ::::~ :::::::::::::
16
32(1
16
32
16
32
14c
16c
(2S)
Do
M. gerardi Waldst. and Kit. ... . .
Af. glutinosa M. Bicb ._ _ . .
Af. fteto Willd ..
(29, 28)
(29, 28)
an
(25, 28)
(It)
M.hispida... __ _ _. .... . ....
31. intertezta Mill ._ ..
(2:1)
(2:3)
M. laciniata Mill ...
16d
IB
16c
(29, 28)
(29, 28)
(29, 28)
8c
(78)
Do ...
lfid
32
16
16
32,35
16o
16d
16
IB
16, 17 or 18
16
16d
32
16
(25, 28)
M. lupulina tiipicti Urban ... .. .
3f. maculata Willd ... -
(«)
(25, 28)
(.29,28)
(23)
(21, 28)
(29, 28)
3f. media Pets ... ..
3d. minimal* ... _ ... .
Af. murex Willd ._ -. -
M. muricata (L.) All-. . ..
(23)
(29, 28)
(23)
M. olteaeformis Guss. . .... .... .. ...
(29, 28)
(25, 28)
(3)
(29. 28)
(78)
M. pentacycta DO ' ... _ .
M. platycarpa (L.) Trautv ..-- -- -■■ ---
8
Do
Af. raiiata D. (syn. Trigonella radiata Hoiss.) . ...
16c
16
16
14
16
32
16
(23)
(«)
(25,28)
(23)
(23)
(23)
(23) ■
lfid
(78)
Do.-_ .
32g
32c
16
16
]fi
16
16
16
16d
Ific
ieg
16
16c
16
16
IB
16
(19)
A/. scutellata Mill... ... .._.__ .. .. .. ...
(23, 28)
(23)
(25, 28)
(25, 28)
M. tornata Mill. .. .
(25, 28)
M. tribuloides Desr ___ ._ .. .._ .
(29, 28)
M. truncatula Gaertn
(25, 28)
31. tuberculata Willd . ._.
(29, 28)
MAurbinata Willd .
(29, 28)
Melilotus alba Med. [Desr. (?)] ...
8d
(19)
(3)
(2:0
31. italica (L.) Lam _ ._ ..! _ .
(8)
(3)
(8)
(3)
8
.... .
(10)
Do.
16c
16
16
16
16d
(IS)
(8)
(3)
31. sulcata Desf. _ __ _
(23)
1024
YEARBOOK, 193 7
Tahle 1. — Chromosome numbers in legumes — Continued
Name
M. taurica Set
M. wolgica Poir__
Millettia japanica A. Gray-.
Afimosa pudica L
Onobrychis crista-galli Lam.
0. vieiaefotia Scop
Do..
Ononis atopecuroides L
O. bijlora Desf
O.fruticosa L
0. hircina Jac(i
O.nctlrixL .
0. ornithopodiodes L ,„_
O. reclinata L _
O. rotundifotia L-
O. spinosa L _-.
0. mscosa L
Ornithopus sativus Rrot
Oxytrapis halleri Bungc
O. rishirknsis Matsum
0. uralenm Pall. [DC]
O. vaginata Fisch
Pachyrhizus angulatus
Parochetus communis...
Phaseolus aconiiifolius Jacq
P. acutifolius A. Gray
P. angularis Willd. [(Willd.) W.
P. aureus Roxb
P. capensis Thuub
P. ckrysanlhos Say
P. lunalus L _.
Do.
F.Wight].
P. mulliflortts Willd.
Do
P. munga L
Do..
P. nigerrimusJusz.
P. radiatus L
Do
Do
P. irilobus __
P. vulgaris], _
Do..
Piptantkus nepalensis Bweet.
Pisum amense L
Do
P. elalius Bicb
P.fulrurn Sibth. [Sibth. and Sm.]_
P. humite Boiss. [Boiss. and NoC)..
P. jomardi Sehrank
P. sativum L_._
Psoralea bUuminosa L
Do..
P.glandulosaJj..
P. macrostachya
P. pataestina L ' _. .. .
Ebynchosia phaseoloides DC.
Robinia boyntonii Asho
R.ferlilis Asho
R. hartwigii Koohno
R. hispida L
Do
R. kelscyi Hntchins
R. luxurians (Dieck) Schneid.
R. psevdoacacia h..
Do —
R. riscosa Vent
Securigcra coronUla DC
Sexhania acukata Pors
Soja hispida Monch
8. max, lllini variety
Sophom angustifolium Sieb. and Zucc-
S. chinensis G.[G. Don]
Chromosome
numbers
8
21
11
U
10
10
10
20
'J
10 I
Referenco
no.
Ifi
Kio
14
22
32
32
32
32 (30)
32
32
64
32
32 (30)
32
lfi
16
T.3
16
10
16
22
22
22
22
22
22
22
22c
22
24
22
22c
24
22
22g
IS
14
14
14
14
14
14t
' 20c
'20
20
<20
22
30
22
~V2~
40
40
(«)
(6)
(44)
(44)
04)
(12)
(SI)
(fi)
(S)
ifi)
(«)
ifi)
(6)
(«)
(6)
d)
(6)
Ui)
(4)
(66)
(4)
(4)
(65)
(12)
(J)
W)
(41)
(.41)
(7)
(16)
(«i
(4D
(40)
(41)
(4D
(S3)
(71
(43)
US)
(63)
(4D
(44)
(4D
(5)
(«5)
(«)
(.50
(61)
(Si)
(SI)
(S)
(48)
(47)
(47)
US)
un
(7)
(83)
(S3)
(S3)
(S3,
a»)
(.83)
(83)
U7)
(4)
(83)
(7)
(44)
(4D
(SO)
%
i Approximate.
MISCELLANEOUS FORAGE LEGUMES 1025
Table 1. — Chromosome numbers in legumes — Continued
Name
S. daeidii Kon
Sophora flavescens All
S.japonica B
jS. moorcroftiaua Bentii
Spartiumjunceum L___
Stoainsoniu galegifolia E. Br. var. albiflora LJndl— .
Tephrosia hookeriana Wit. and A.
Thermopsis alternijlom Kegel [Regcl and Sehmalb.]
T. montanaNutt ..- —
Do-
Chromosome
numbers
Trifolium albnpurpureum T. and G-
T. atexandrinum
T. alpestre L
Do..
10
T. ambiguum~Sl. B.
T. angustifolium L_„
T.arvenseli
Do..
T. badium.
T. campeslre
T. ciliolalum Benth. (T. ciliatum Nutt.)_
T. dichotomum H. and A —
T.filiorme L
T.fragiferum L
Do_.
T.fucatum'Lvi&l-
T. glomeratum
Do-
it, hybridum L.
Do-
T. incarnatum Ii_
Do-
Do
T. tappaceum L
Do.. _
T. lupinaster L
T. maritimum Hurts .
T. medium L
Do..
T. microcephalurn Fuisli.
T. minus
do-
it, montanum L.
Do.
T. obtusiflorum IIook_.
T. ochrokucum
T. pannonicum Jacq.-.
Do-
Trifolium parvifloritm Klirh.
T. pratense L
Do.
Do
Do
T. procumbent L
1. reftezum L _...._.
1. repens L
Do
Do-
Do _
Do
Do
1. resupinatum L —
Do
T. rubens L - -
T. scabrum L
1. spadiceum L -
1. sguarrosum L _-_ --
T. mbtemmeum _ _
T.tkalii _ _
T.tumens Stov -
T. variegatum Ktitt -- - --
T. wormskoeldii Lehm
Trigonella balansae Boiss. IBoiss. and Reut.-]-
T. calliceras Fisch- - ---
9 CO
' 48-4!)
< 12
'12
14
If)
lfi
18
25
16
(48-52)
18
10
10
16
16
14
14
16
32
14
10
~16d
14d
16
10
48
16
«80
16
32
16
16
'130
16
14d
(24)
14
16
16
32d
(24) 28
16
16
48(?)
16
16
Refereneo
(S)
(s)
(s)
U0)
(S)
an
(44)
(i)
(71)
(6)
(82)
(82)
U)
(42)
(42)
(40
(1)
W)
a)
a)
(««)
(82)
(42)
(1)
(42)
(82)
(1)
(82)
(1)
(42)
(1)
(42)
(67)
(1)
«*)
(42)
%
M
(82)
(1)
(82)
(1)
(41)
(82)
(D
U)
(42)
8?
(St)
(4D
(61)
(42)
(82)
(51)
(/)
(44)
(20)
(42)
(61)
0*)
u«
(42)
(42)
(42)
(82)
(1)
(42)
(82)
(82)
(76)
(76)
* Approximate.
1026 YEARBOOK, 1937
Table 1. — Chromosome numbers in legumes — Continued
Xame
7. coerulen (L.) Ser --
7. comiculata h -
7. cretica (L.) Desr
7. foenumgraecum L... -r—
7. glomerata Hort. (syn. Atedkago brachycarpa I isch.)~-------
7. melihtus coeruka A. and G. (syn. Melilotus coeruka Desf.).
7. monspeliacaJj
7.polycerata L --
7. striata L. (syn. 7. cancellata Desf.) —
TJlex europaevs L
V. nanus Forst
V. paniftorus Pourr - -
Vicia alpestris Sleph. (Stev.) --
V. amoena Fisch
Do.
V. amphkarpa L
V. angustifolia L .
V. atropurpurea Desf.
Do .
V. aurantia Boiss -
V. bithynlca 1,
V. calcarata Desf..
V.cracca L
Do.
Do.
Do.
V. dasycarpa Ten..
V. dnperma DC —
V. dumetorum
V. erviformis Boiss.
V. enilla Willd
V. fatal
Do.
Do
V. gracilis Lois
Do.
V. grandiflora Scop.
Do.
V. hirsuta 8. F. Gray
V. hybridal,..
V. hyrcanlca Fisch. and Mey.
V. lathyroides 1/
V. lutea L
Do -.-
V. macrocarpa
Do.
Do
V. monantha Desf..
Do
V. musquinez Bosc.
V. wirbonensls'L—.
Do.
V. orobus DC
Do.
V. pannonica Cranlz.
Chromosome
numbers
Do.
V. perwrina L.
Do
Do.
V. pkta Fisch. and Mey.
Do -
V. pisiformis
I7, pseudocracca Bortol.-.
Do
V. pseudoorohus
Do
V.pyrenaica Pourr
Vicia salwa L
Do.
Do
V. scpium L
V. serratifolia Jacq
Do
V. skula Guss
V. silvatica L
Do
7c
16
10
lfic
I fie
18
16
16
28
16
96
40
96
28
Reference
no.
(23)
(76)
CM)
(IS)
(6)
24
10
12d
I4d
14
14(1
14
12c
14
2S
14c
14d
11
14
14(1
12k
14
14c
14d
12c
12
12
34c
10
12
14d
14
14(1
12c
12c
12
14
14c
12
14
14
12R
14(1
14c
14
:s)
05}
(S)
(.5)
a,)
(5)
(.5)
(H)
(78)
(75)
(76)
(7S)
(7,5)
(6S)
(■34)
(7.5)
(S4)
(S7)
(76)
(78)
(7.5)
(75)
(7,5)
(Si)
(34)
(7S)
(60)
(57)
(m
(78)
(76)
(78)
(75)
(75)
(75)
(S4)
(34)
(78)
(75)
(78)
(34)
(76)
(78)
(75)
(84)
(78)
(7-5)
(78)
(75)
(75)
(78)
(78)
(34)
(75)
(78)
(75)
(34)
(75)
(68)
(68)
(34)
(34)
(68)
(44)
(39)
(7.5)
(78)
(76)
(S4)
(78)
(75)
MISCELLANEOUS FORAGE LEGUMES
Table 1. — Chromosome numbers in legumes — Continued
1027
Name
V. tenuifolia Roth.
Bo.
V. tetrasperma Moencll.
Bo.
V. unijuga A. Br-
no
Uo-
Do.
Do _.
V. villosa Roth.
Do.
Vigna caljang (Burm.) Walp..
Do_
V. glabra Savi
V. owahuensis Vog
V. sesquipedalis A. I. I'ierters [P. Ageaoili]
V. sinensis Endl _
V. unguiculata (Ij.) Walp _
V. vtxillala Benth
Wistaria brachnbolnjs Sieb. and Zuec
W. floribunda \1C
W.frutescens (L.) Ppir
W. macrostaehya Nutt _ ._
W. multijuga Van lloutte (W. cliinensis vat. mxMip.iga Ilook.)-
W. sinensis Sweet.
W.venusta Render and Wilson
Chromosome
numbers
6
12
24c
14c
12c
24
14c
22
24
22
22
22
22
Reference
no.
(78)
05)
(78)
(75)
(78)
(68)
(44)
05)
(S9)
(78)
(76)
(41)
(ft?)
(7)
(7)
(44)
(44)
(40
(7)
(40)
(40)
(64)
(64)
(4)
(64)
(64)
References for Chromosome Numbers
(1) BlEIEH, H.
1925. CHROMOSOMENSTUDIEN BEI DER GATTUNG TRIFOLIUM. Jalirb.
Wiss. Bot., 64: [004]-G30, ill us.
(2) Bheslavetz, L., Medwedewa, G., and Magitt, M.
1934. ZYTOLOCISCHE UNTERSUCHUNGEN DEB B ASTrFLANZEN (APOCY-
NCJ1, BOEHMERIA, HIBISCUS, ABUTILON UND CBOTALABIA).
Pflanzenzuchtung 19: [229]-234, illus.
(3) Cannon, W. A.
1903. STUDIES IN PLANT HYBRIDS: THE SPERMATOGENESIS OF HYBRID
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1030 YEARBOOK, 1937
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1933. studies in the development op the female gametophyte in
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BREEDING
MISCELLANEOUS GRASSES1
H. N. VINALL,2 Senior Agronomist;
M. A. HEIN, Agronomist, Division of
Forage Crops and Diseases, Bureau
of Plant Tnduslry
X HE grass family, known by botanists as the Gramineae, is the
most important and widely distributed of all plants. Grasses are
found from the Tropics to the Arctic Zone, and in deserts and swamps.
To this group belong some of the most important cultivated crops
such as corn, wheat, oats, rye, barley, rice, sugarcane, and the sor-
ghums and millets.
Grass breeding really began in a remote time with the development
of these crops from various species of wild grasses. This breeding,
however, had for its purpose an increased production of food grain
rather than any improvement in forage value. Pastoral agriculture
was founded on the utilization of grasslands for grazing domesticated
animals; and primitive peoples still migrate, with their flocks, in
search of grass which provides the entire sustenance of these animals.
It is only within the last 30 years that any serious effort has been made
to increase the forage production of grasses.
In different parts of the world natural selection took place under the
influence of climate, and thus we find the original grasslands of each
country characterized by certain genera and species, which are native
or indigenous there. As civilization developed and intercourse between
nations became easy, the native grasses of each country were intro-
duced and domesticated in countries having similar climates, so that
grasslands are now less distinctive from a national viewpoint than
formerly. However, there still remain more or less well-defined centers
of development for each of the important grasses, and these centers
are important as sources of breeding material.
GERM-PLASM SOURCES FOR VARIOUS GRASSES
Groups of related grasses h ave become concentrated in certain parts
of the world as a result of their reactions to climatic conditions. It
is in such regions that these genera are found in the greatest abundance,
and here also the widest variation may be expected in habit of growth
within the species. These development centers have been outlined
broadly in figure^ 1, which may be considered as a graphic illustration
of grass adaptations and the chief grass resources of the world, with
the natural migration channels of these grasses indicated, of course,
without any attempt to present details. The most important genera
_ ' The purpose of this article is to bring together as far as possiblo the available information as to the breed-
ing m progress and that contemplated with all grasses of agricultural importance with the exception of tim-
othy, sugarcane, and the cereal grasses such as corn, sorghum, rice, wheat, rye, oats, and barlev is con-
siderable breeding work lias been done with timothy, it is discussed in a separate article.
1 Died Feb. 22, 1937.
1032
'%> — '§.P— _ 140 <20 100 80 6 0 *.0 20 O 2 0 4.Q 6 0 80 tOO 120 140 (60 180
?QSfr& 1 J _.__ ^--/tundra,.
to
n
tq
t-<
tn
o
to
o
to
to
180 I 13 0
0 180
Figure 1. — Development centers of various important grasses.
©
CO
1034 YEARBOOK, 1937
and species in each of the 16 regions are listed in table 1 (in the appen-
dix). The boundaries or limits of these regions are obviously not
exact, and wide variations occur within certain regions because of
mountain ranges and other physiographic features that affect
vegetation.
Region 1 includes most of western Europe whore the annual pre-
cipitation is 20 inches or more and the temperatures are mild. Prac-
tically all of the so-called "tame" grasses now grown in southeastern
Canada and the humid part of the United States north of the Cotton
Belt are native in region 1 and were introduced from there by early
settlers in North America. This region is rich in species and varieties
of timothy, bluegrass, orchard grass, ryegrass, redtop, bentgrass, oat-
grass, and fescue. Other grasses abundant in this region, but of little
or no agricultural value, are velvet grass (FIolcus lanatus)? matgrass
(Nardus stricta), and the other moorland grass (Molinia caerulea).
These constitute the principal grass cover of wet heaths and moorlands
throughout this region.
Region 2, the Mediterranean region of Europe and Africa, charac-
terized by low rainfall and rather poor soils, is the native home of the
annual species of Avena (wild oats), bromes, and fescues. Most of the
winter annual grasses now growing in the foothills of southern Cali-
3 The authorities for the botanical najnes used in this article are given in table 5 of the appendix.
COMPARED with the ivork in several other countries, very little
has been done in the United States in breeding any of the grasses
except timothy. Orchard grass, bluegrass, redtop, bromegrass,
bentgrass, Bermuda grass, carpet grass, and all other grasses ordi-
narily used in seeding pastures and lawns are mixed populations
consisting of many strains that vary in such important character-
istics as date of maturity, disease resistance, leafiness, number and
vigor of stolons and rhizomes, and viability and abundance of seed.
Because of these wide variations, there is a great opportunity for
improvement by simple selection processes, and probably still
greater possibilities in hybridization. The widely differing uses of
grass, however, necessitate a close scrutiny and thorough examina-
tion of the variants from the standpoint of each possible use. More-
over, improved strains developed by British or other foreign workers
are not likely to represent the best for our own country, since maxi-
mum values in plant breeding are attained only by aiming for
close adaptation to local conditions. In the development of improved
grasses, we shall have to solve our own problems by a systematic
attack based on regional differences.
MISCELLANEOUS GRASSES 1035
fornia are of Mediterranean origin. In addition red fescue, canary
grass, and Harding grass originated in region 2. The esparto or alfa
grass used in the manufacture of fine paper grows naturally in northern
Africa. Grasses that are abundant in this region but of little value
include many species of both Aristida and Stipa.
Region 3 includes the eastern or low-rainfall section of the Union
of Soviet Socialist Republics and practically all of Siberia. Here,
where the average rainfall is less than 20 inches and the winters are
very severe, a group of extremely hardy and drought-resistant grasses
has developed, including the crested wheatgrass which has proved so
valuable on the northern Great Plains of the United States. On the
dry, cold steppes are many species and varieties of wheatgrass (Agro-
pyron), wild-rye (Elymus), reedgrass (Calamagrostis), and "chee" or
"tshee" grass {Stipa). The small fescues such as the sheep fescue are
present but not so characteristic of this region as the Agropyrons.
Region 4, including southeastern Union of Soviet Socialist Repub-
lics, western China, and that ancient cradle of the human race, Asia
Minor, Persia, and Afghanistan, is peculiarly important as the native
home of several cereal grasses. All of this region is very dry and a
considerable part is actual desert. While. not so important from a
forage standpoint, the native grasses of tins region include what are
believed to be the progenitors of wheat, emmer, einkorn, and rye.
Numerous species of wheat (Triticum), rye (Secede), and their near
relatives the goatgrasses (Aegilops and Haynaldia) are found here.
The wild barleys (Hordeum spp.) are common, and bulbous bluegrass
(Poa bulbosa) is almost everywhere. Meadow foxtail, sweet vernal-
grass, red fescue, and Johnson grass are other important grasses found
in region 4.
Region 5 includes Tibet, the western provinces of China, and eastern
Mongolia. This is a region of high mountain ranges, cold, dry pla-
teaus, and deserts. On account of its inaccessibility less is known
about the grasses of this region than of any other part of the world.
The grasses that have developed here would assuredly be drought-
resistant and able to withstand other climatic extremes. At least four
species of bluegrass and as many fescues have been reported from this
region, along with several species of wheatgrass and wild-rye. Needle-
grass (Stipa spp.) and sedges (Carex spp.) are widely distributed.
Region 6 includes eastern Siberia, Manchuria, northeastern China,
Chosen, and Japan. Although attention has chiefly been given to the
many soybean varieties in this region, it is also important as the home
of most of our cultivated millets and that group of sorghums known
as kaoliang. Foxtail millets, broomcorn millet (proso), and Japanese
millet are all widely distributed and show a great variety of forms in
this region. The Japanese lawngrass (Zoysia japonica) and Manila
grass (Zoysia matrella), both of which appear valuable in the United
States, are at home here. Among the loss important grasses are many
species of Arundinella, Calamagrostis, Ischaemum, and Panicum.
Region 7, including southeastern China, most of India, Burma, the
Malay Peninsula, and adjacent islands, is largely tropical and has a
heavy rainfall except in northern India. Such important cultivated
crops originated in this region as sugarcane, rice, and bamboo ; and
also the forage grasses, Bermuda grass, Anglcton grass, and centipede
1036 YEARBOOK, 1937
grass. There are many other species and varieties of Andropogon,
Cynodon, Eleusine, Oryza, Panicum, Paspalum, Saccharum, and Sor-
ghum that have not yet proved of value under cultivation but may be of
some importance from a breeding standpoint. Cogon grass, said to bo a
useful pasture grass in China and the Philippine Islands, is of doubtful
value in the United States on account of its aggressive rootstocks.
Region 8, including Australia, New Zealand, and Tasmania, has a
very distinctive vegetation, and many of the native grasses of this
region are found nowhere else in the world except in small experi-
mental plantings. The interior of Australia is very dry, almost
desertlike. Along the coast where rainfall conditions are favorable
the pastures and meadows are composed almost entirely of grasses
and legumes introduced from Europe. In the drier portions native
grasses supply most of the forage, and the most important of these
are perhaps Mitchell grass, Wallaby grass, kangaroo grass, red grass
(Themeda sp.), Flinders grass, and tussock grass. On the sand ridges
in the semidesert area spinifex (Triodia spp.) is very abundant.
Common Mitchell grass, curly Mitchell grass, and Wallaby grass
have all been introduced into the United States, but they seem to be
of little value here. The tussock grass of New Zealand (Poajlabellata)
appears to be a very desirable grass, but so far all attempts to introduce
it have failed. So much of Australia is desertlike that many grasses
such as the annual bromes, fescues, Avenas, and Hordeums, which are
not considered desirable in the United States, are appreciated there.
Region 9 consists of the equatorial part of Africa, some of which is
occupied by dense forest. In parts where the rainfall is not too heavy,
grasses abound in the open places of the timbered areas and in exclu-
sively grass-covered lands or savannas replete with wild game animals.
Here are found numerous species of Sorghum, Pennisetum, Panicum,
Hyparrhenia, Andropogon, Ehrharta, and Themeda. Molasses grass
and jaragua grass originated here, but are now more important in
South America. In the highlands of Ethiopia are found many Hor-
deums (barley relatives). Sudan grass originated near Khartum,
and other varieties of grass sorghum occur in profusion in this region.
Pearl millet is native here also and originally was an important food
crop of the inhabitants.
Region 10 is composed of that part of Africa south of 10° S. latitude
and the adjacent island of Madagascar. The annual rainfall varies
from about 40 inches in the northern part to actual desert conditions
in Bechuanaland and southwestern Africa. The rains come largely
during the summer months (winter in the Northern Hemisphere),
and in this period they are fairly adequate except in the desert regions
of Bechuanaland and along the West Coast. Temperatures arc
rather high except in a very limited mountain section in eastern South
Africa. Plants that have developed under these conditions in Africa
are well adapted to the Cotton Belt of the United States. Practically
all of our cultivated varieties of sorghum originated in this region, and
from there came Rhodes grass, Natal grass, and woolly fingergrass.
Many species of Chloris, Cynodon, Digitaria, Ehrharta, Hyparrhenia,
and Themeda contribute forage for their domestic and wild animals.
Grasses that are abundant but of little value include the Aristida and
Trichopteryx species, especially the latter.
MISCELLANEOUS GRASSES 1037
Region 11 comprises most of Brazil, eastern Bolivia, Paraguay,
Uruguay, and the northeastern part of Argentina. In this part of
South America the rainfall is heavy (30 to 70 inches) and the tempera-
tures are subtropical to tropical. Here we find an immense area of
open parklike grasslands, including the campos of Brazil and the
pampas of Uruguay and Argentina. The basin of the Amazon, with
a rainfall of over 80 inches annually, is a dense, junglelike forest of
little importance from a grass standpoint. Notwithstanding the
extent of the grasslands in South America, few if any of the native
grasses have shown any forage value in the United States or in their
homeland. The superior forage grasses of South America were almost
without exception introduced from tropical Africa, the native pampas
grass being used chiefly as an ornamental because it is unpalatable.
The molasses, jaragua, Guinea, and Para grasses all appear to have
been introduced many years ago and are now widely distributed in
region 11. They provide a large proportion of the pasturage for live-
stock, which is one of the main sources of revenue in this region.
Region 12 comprises Chile and the western or Andean sections of
Argentina, Bolivia, and Peru as far north as the Gulf of Guayaquil.
Except for southern Chile and Patagonia, this is a region of high
altitudes and low rainfall. Although important as the native land
of the potato and other Solanaceae, it does not appear promising as
a source of forage grasses. Axonopus scoparius, a relative of carpet
grass called "cachi" in Bolivia, is said to be a good pasture grass.
This is found on the moist meadows of the eastern slope of the Andes.
The forage in the high mountain valleys and plateaus is derived mostly
from species of Festuca, Poa, Calamagrostis, and Muhlenbergia.
Grasses that are abundant but have little agricultural value comprise
numerous species of Eragrostis, Stipa, Trisetum, and Piptochaetium,.
The last-named genus is said to be encountered everywhere in this
region, although it is uncommon in other parts of the world.
Region .13 includes southern Mexico, all of Central America and
the West Indies, and Colombia, Venezuela, and Guiana in South
America. This region, surrounding the Caribbean Sea and the Gulf
of Mexico, is largely in the Tropics, but differences in altitude give it
an extremely varied climate. It is also the home of the early Mayan
civilization and the. source of several of our most important food
plants, including corn. In the Orinoco Basin of South America are
the llanos, broad savannas or grasslands similar to the campos of
Brazil. Several very useful forage grasses have been obtained from
region 13, where they appear to be indigenous. The best known of
these are teosinte, gamagrass, Bahia grass, St. Augustine grass,
Guatemala grass, carpet grass, and wildrice. This region also abounds
in species of Trisetum, Setaria, and Andropogon, most of which are of
little or no value agriculturally. Sourgrass (Trichachne insularis) is
very common but worthless.
Region 14 in western North America comprises a broad expanse of
rugged mountains, dry plains, and plateaus extending from the Peace
River section of Canada to southern Mexico. In all this region the
rainfall is very limited, varying from actual desert conditions to 20
inches annually, while the temperatures range from very hot in
Mexico and Arizona to very cold in northern United States and
1038 YEARBOOK, 1937
Canada. The flora is rich in native grasses except for the desert
areas, where the dominant vegetation consists of woody shrubs and
cacti. Among the native grasses that contribute most to the sus-
tenance of livestock are a great variety of wheatgrasses, bluestems or
beardgrass, gramas, buffalo grass, sandgrass (Calamoviffa sp.), wild-
ryes, fescues, bluegrasses, mesquite grasses (Hilaria sp.), and the
Sacaton or dropseed grasses. Grasses that are common but of no
particular value include the needlegrass (Aristida sp.), spear grass
(Stipa sp.), and squirreltail grasses {Sitanion spp.). Foreign grasses
that have proved adapted in this region include crested wheatgrass,
awnless bromegrass, bulbous bluegrass, and Sudan grass.
Region 15, consisting of southeastern Canada and the northeastern
United States, was originally occupied almost exclusively by hard-
wood and coniferous forests. Naturally, valuable native grasses are
scarce except in the western part of the Corn Belt, which was from
early days an open prairie carpeted with big bluestem and little
bluestem. Both of these are excellent forage grasses. The rainfall
in this region is usually adequate, and as the country was settled by
people from Europe, the land when cleared of timber was seeded to
introduced grasses from region 1. At the present time most of the
pastures and meadows are occupied by these European grasses, which
have proved admirably adapted to the climatic conditions here.
Foxtail millet and Japanese millet, introduced from Europe but
natives of Asia, are also grown rather extensively. Reed canary
grass, big bluestem and little bluestem are about the only native
grasses that have proved important. Other native grasses of minor
importance are noted in table 1, because they may be of some value
from a breeding standpoint.
Region 16 is that part of the Eastern United States south of the 60°
isotherm. This is the original Cotton Belt, and while limited in area,
it has been set apart from region 15 because of its marked difference
in grass flora. This region was also originally a forest, and when the
timber was cleared off by settlers European grasses proved unadapted,
but more tropical grasses from Asia, Africa, and Central America have
occupied the cleared lands where the soil is sufficiently fertile for these
introduced grasses to compete with the omnipresent native broom-
sedge and other Andropogons. The most important of the intro-
duced grasses are Bermuda, carpet, Dallis, and Johnson grasses, and
they provide the bulk of the pasturage and hay in the region. Napier-
grass, Japanese cane, and pearl millet also thrive here, but will not be
discussed further at this time, since the situation in regard to grasses
in the United States is presented in the appended detailed maps.
The native grasses, some of which may offer possibilities in breeding,
are listed in table 1 . Texas bluegrass is one of these already used in
crosses with Kentucky bluegrass.
CLIMATIC ADAPTATION OF PRINCIPAL FORAGE GRASSES
OF THE UNITED STATES
The effective improvement of grasses by breeding requires an under-
standing of their inherent climatic relationships. In the United States
this relationship is best expressed by dividing the country into six
MISCELLANEOUS GRASSES
1039
regions as illustrated in figure 2. This generalized picture of a situa-
tion that has developed naturally under the influence of prevailing
climatic factors provides a basis for the organization of grass breeding
in this country. The introduction of other foreign grasses in the
future may conceivably change the situation, especially in the South-
west. At this time, however, the opportunities for success in breeding
appear to lie in working with those grasses that have met the require-
) INTRODUCED GRASSES
NORTHERN TYPE
) WINTER ANNUALS EXCEPT
ON IRRIGATED LAND
Figure 2. — Grasslands of the United Slates, showing the dominant type of grasses in
each as determined by the climate.
ments of man and have been most productive during the past cen-
tury. The most outstanding of these are discussed briefly.
In considering the distribution maps it must be understood that
the limits indicated are not exact. Beyond the boundaries where
a particular grass is really important it will be found less and less
frequently struggling to survive under increasingly unfavorable
conditions which results in an overlapping of adjacent distribu-
tion areas.
Kentucky Bluegrass, Canada Bluegrass, and Timothy
Kentucky bluegrass, Canada bluegrass, and timothy were intro-
duced from Europe by the early settlers, and as the land was cleared
of forest they spread over practically all of the humid part of the
United States north of the 60° isotherm, as indicated in figure 3. In
addition to the areas shown, these grasses are abundant in region 5 of
figure 2, which is also humid. None of them is sufficiently drought-
resistant to be grown successfully in arid or semiarid sections except
under irrigation. These grasses have become the leading hay and
pasture grasses of the United States and the adjacent sections of
Canada. They proved so well adapted to climatic conditions here
1040
YEARBOOK, 1937
that they now occupy much more extensive areas in North America
than they do in Europe.
KENTUCKY AND CANADA BLUEGRASS.
am TIMOTHY
Figure 3. — Sections of the United States where Kentucky bluegrass and Canada
blucgrass are well adapted and of primary importance.
Redtop AND the Bentgrasses
Although redtop and the bentgrasses (species of Agrostis) are not
so important agriculturally as are Kentucky bluegrass and timothy,
redtop is valuable for both hay and pasture on wet or acid soils, and
Figure 4. — Sections of the United States where redtop and the bentgrasses are well
adapted and of primary importance.
MISCELLANEOUS GR.4SSES
1041
the bentgrasses, because of their fine turf, are used extensively on lawns
and golf courses. The sections where these grasses are of major im-
portance are shown in figure 4, but they thrive equally as well in
region 5 of figure 2, and the use of the bentgrasses for fine turf is com-
mon throughout the whole redtop region. Redtop is most highly
regarded in Illinois, where most of the seed is produced. It seems
better suited to the poorly drained, rather unproductive clay soils of
that section than any other grass.
Orchard Grass and Tall Oatgrass
The approximate range of distribution of orchard grass and tall
oatgrass is shown in figure 5. Of these two introduced grasses,
orchard grass is the more common and undoubtedly the more valu-
BORCHARD GRASS ami, TALL OATGRASS
0IDMEADOW FESCUE
FigureS. — Sections of ihe United Slates where orchard grass and tall oatgrass are well
adapted and of primary importance.
able because of its longevity and its value in pasture mixtures. It is
more tolerant of shade than bluegrass and produces better on poor
soils. The results obtained in the improvement of orchard grass in
Europe and Australia lead to the belief that much may be accom-
plished with it here. One of the obvious points of weakness in tall
oatgrass is seed shattering which has already been overcome by selec-
tive breeding.
Bermuda, Johnson, and Dallis Grasses
Bermuda, Johnson, and Dallis grasses together with carpet grass are
the principal hay and pasture grasses of the Cotton Belt. All of
them were introduced at a comparatively early date and have spread
naturally over most of these States. Although Bermuda grass and
Johnson grass are found more or less frequently north of the limits
indicated in figure 6, they are sensitive to low temperatures and grow
1042
YEARBOOK, 1937
only during the frost-free period; hence they are unimportant outside
of the section indicated in figure 6 except in the irrigated sections of
southern California, Arizona, and New Mexico. In these States both
arc abundant, but Johnson grass especially is considered a weed and
Bermuda grass is a doubtful asset. Both grasses invade irrigated
— 'fHf-\-_
^x 'i ;
: '.
i !
*-- >
-[) l^x--"'">w
1 ' \ j/ )
i
;
-. ;-'
' y~'t
~TT^f»
QBERMUDA GRASS \:
Hm JOHNSON GRASS AND DALLIS GRASS
Figure 6.-
-Sections of the United Stales where Bermuda, Johnson, and Dallis
grasses are well adapted and of primary importance.
cultivated lands and are difficult to control because of their aggres-
siveness. Dallis grass, however, is gradually coming to be recognized
as a valuable constituent of pasture mixtures on irrigated lands
in these States.
Carpet, Napier, Bahta, and Para Grasses
Successively more tropical and less winter-hardy, carpet, Napier,
Bahia, and Para grasses are confined almost entirely to sections of the
United States indicated in figure 7 and to extreme southern parts of
California and Arizona. Carpet grass is much more common than
the other three and next to Bermuda grass is foremost in pasture
improvement. Napier grass, because of its large, coarse growth, may
be used effectively as a soiling or silage crop in addition to its
value as a supplemental pasture.
Awnless Bromegrass and Crested Wheatgrass
_ Awnless bromegrass and crested wheatgrass, unlike the grasses just
discussed, are extremely winter-hardy, and both are very drought-
resistant. Both were introduced from Europe and have been found
most useful in the northern parts of the Great Plains and of the inter-
mountain region (fig. 8). Bromegrass, however, is proving valuable
MISCELLANEOUS GRASSES
1043
BAHIA AND PARA GRASSES
DID CARPET AND NAPIER GRASSES
Figure 7.- Sections of the United States where carpet, Napier, Bahia, and Para grasses
are well adapted and of primary importance.
Figure S.-Seclions of the United States where .widen hromegrass and crested wheat-
grass are well adapted and of primary importance.
in the North Central States in pastures and meadows, especially in
mixtures with alfalfa. The chief objection to it, the difficulty encoun-
tered in eradicating it, may be overcome by selective breeding Graz-
ing animals are very fond of both crested wheatgrass and bromegrass
1044
YEARBOOK, 193 7
Native Short Grasses and Prairie Grasses
Buffalo grass, the gramas, mesquite grasses, bluestems, and wheat-
grasses supply a very large part of the pasturage and wild hay pro-
duced in the Great Plains. The distribution areas of all of these
except the wheatgrassesare indicated in figure 9. Much of this
region is semiarid, and in order to grow successfully here grasses
must be able to endure periods of severe drought. All of these with
the exception of big bluestem are preeminently drought-resistant, and
the chief object in breeding will be improvement in productiveness of
QBLUE GRAMA
□JUBUFFALO GRASS
^BLACK HAIRY,and CROWFOOT
GRAMAS, CURLY MESQUITE,
AND TOBOSA GRASS
^BIG AMD LITTLE ).RF4 nF MA ra
BLUESTEMS AND ' AREA-SF . MAJOR
INDIAN GRASS
IMPORTANCE
Figure 9. — Sections of the United States where native short grasses and prairie grasses
are well adapted and of primary importance.
forage and viable seed. _ The actual distribution of each grass is con-
siderably wider than is indicated on the map, which outlines the areas
where each grass is of major importance and where their breeding is
warranted. _ Big bluestem and little bluestem are adapted quite well
to the outlying stippled area but are of minor importance there because
most of the land is now under cultivation and introduced grasses are
more productive. These two bluestems are found in small isolated
colonies as far south as the Gulf coast. Indian grass is found grow-
ing in combination with the bluestems but rarely constitutes over 5
percent of the herbage.
Slender and Western Wheatgrasses
Western wheatgrass is found growing naturally all over the Great
Plains except the extreme southern part. In the depressions where
the soil is heavier, western wheatgrass often occupies the land to the
virtual exclusion of all other grasses. Its foliage is rather harsh but
palatable and very nutritious especially when immature. Slender
wheatgrass is more widely distributed than western wheatgrass,
although it does not extend so far south in the Great Plains as the
MISCELLANEOUS GRASSES
1045
latter, and being a bunch grass it seldom occupies any large area to the
exclusion of other grasses. The regions where these two native
grasses are of importance are outlined in figure 10. Both are valu able for
ff^
miiiiiHiiiHi \\\ ^ r1"^-!?^^ ~^\ /^i •< \f
( =^= / L ,-— E
vM\ fill"
lv- V I i /^^J§
vv fliHii
B SLENDER WHEATGRASS
HID WESTERN WHEATGRASS
j ' 1 1 1 1 1 1 n "*%
Figure 10. — Sections of the United Slates where slender wheatgrass and weslern
wheatgrass are well adapted and of primary importance.
hay as well as pasturage, and less difficulty is found in obtaining viable
seed of these wheatgrasses than of the other native grasses just discussed .
Sudan, Reed Canary, and Other Grasses
The species that have been discussed include nearly all of the
grasses of recognized importance in the United States except Sudan
grass and reed canary grass. Sudan grass, an annual, has been found
useful as an emergency hay crop and for summer pasture in all parts
of the United States, although best suited to conditions in the middle
and southern Great Plains. Reed canary grass is valuable on wet
lands anywhere north of the 60° isotherm. Breeding activities will
no doubt be most productive with these grasses, but there are many
others that should not be ignored, since in them are found useful
characters that may be transferred to the more important species by
hybridization.
WHY THE BREEDING OF GRASS IS WORTH WHILE
Approximately 60 percent (82) 4 5 of the total land area of the United
States is grazed at least part of the year, and a major portion of the
feed obtained by grazing animals is provided by grasses. It is esti-
mated that in 1919 the grazing lands supplied about 49 percent (25)
and in 1929 about 41 percent (83) of the total feed consumed by all
s Italic numbers in parentheses refer to Literature Cited, p. 1074.
5 Acreage of pasture on farms is given for 1934. The National Resources Board also furnished data on
grazing land (ffl, pt. 2, table $, p. 109). The 1930 acreage figures For grazing land not in farms were adjusted
by O. E. Baker for 1934.
1046 YEARBOOK, 1937
classes of farm animals. If the 11,798,065 tons of hay from grasses
other than timothy be included, approximately 43 percent of the
sustenance of our farm livestock must be credited to miscellaneous
grasses.
In addition to the farm animals there are in the United States over
1 million herbivorous game animals (81), including deer, elk, and
antelope. Deer and elk are the most numerous, and they subsist
largely by browsing on trees and woody shrubs, but 10 to 15 percent
of the food of this group consists of grasses.6 The grasses are also
important in providing food and cover for wild fowl.
Results obtained by soil erosion experiment stations 7 indicate that
on various soil types on slopes varying from 4 to 16 percent the losses
of soil by erosion are from 650 to 4,600 times greater where the land
is devoted to clean-cultivated crops as corn and cotton than on lands
with a perennial-grass cover. Besides the reduction of direct losses
through soil erosion and run-off, there is an additional benefit derived
from a grass cover in the conservation of soil fertility, chiefly nitrogen
and organic matter. It has been estimated that there is an average
annual loss of 60 pounds of nitrogen per acre from cultivated soils.
Hopkins (8, p. 559), of Illinois, found 4,000 pounds of nitrogen per acre
in the surface soil of land that had grown corn for 16 years, as com-
pared with 4,914 pounds per acre in the soil of adjoining pasture land.
A determination of organic matter by the combustion method showed
in the soil of old pastures 6.12 percent, new pastures 4.16 percent, and
cultivated soil 2.44 pei-cent (87).
Grass in lawns is the foundation of all landscape effects for private
houses and public buildings. It has been estimated that over $100,000,-
000 is spent annually in the United States on private lawns and at
least $10,000,000 for turf establishment and maintenance in ceme-
teries. To this must be added about $65,000,000 spent annually in
providing the required turf on golf courses, athletic fields, and play-
grounds, and $16,000,000 in providing a ground cover on airports,
road shoulders, and railway embankments.8
An increase in the acreage of grasses and legumes has been definitely
adopted as a national policy because grasslands not only conserve the
soil but also contribute to a better balanced agriculture. This places a
larger emphasis on the work of the breeder.
POSSIBILITIES AND PROBLEMS IN BREEDING GRASSES
In the United States breeding of grasses has received little attention
with the exception of timothy. Orchard grass, bluegrass, redtop,
bromegrass, bentgrass, Bermuda grass, carpet grass, and all other
grasses ordinarily used in seeding pastures and lawns are mixed popula-
tions consisting of many strains varying in such important character-
istics as date of maturity, disease resistance, leanness (fig. 11), number,
and vigor of the stolons and rhizomes, and viability and abundance
of the seed — to name only a few of the many variations. There is,
0 U. S. Dept. of Agr., Bvre.au of Biological Survey, wild life review. 1936. [Mimeographed.]
r The data are taken from unpublished reports or summaries of results from the various stations indicated :
Guthrie, Okla., Soil Conservation Service Circ. L-1121 (1936); Temple, Tex., Soil Conservation Service
Circ. L-1134 (1936) ; Hays, Kans., Soil Conservation Service Circ. L-1134 (1936) ; La Crosse, Wis., Soil Con-
servation Service Circ. L-1122 (1936) .
8 These estimates of expenditures were supplied by John Monteith, Jr., collaborator, Division of Forage
Crops and Diseases, Bureau of Plant Industry, U. S. Department of Agriculture.
MISCELLANEOUS GRASSES
1017
therefore, a great opportunity for improvement by simple selection
processes. The uses made of these grasses are varied as compaied
with those of cotton, tobacco, sugarcane, or even com. This broad
field of usefulness increases the opportunity, but it also implies a
closer scrutiny and more thorough examination of the variants because
a strain that may be of no value for hay purposes might be exactly
the kind needed for pastures or lawns.
It is now rather generally acknowledged that the maximum values in
plant breeding are attained only by breeding plants adapted to local
conditions. Improved strains are not ordinarily found superior under
Figure 11. — Two selected strains of Kentucky blucgrass, showing the variations in leaf
will ill found in individual plants of commercial cultures.
all conditions of soil and climate. There is therefore little reason to
believe that the improved strains of grasses developed by British or
other foreign workers will represent the best attainable here in the
United States. Plant-breeding work with cereals has shown also that
there are different strains of certain disease organisms, such as smut,
and that a grain variety that is almost wholly immune to the ordinary
smut may be susceptible to other strains of tliis disease. The same
condition will probably prevail with reference to the diseases of forage
grasses, which implies additional restrictions and necessitates better
controlled tests in breeding.
Opportunities for the accomplishment of practical results in the
improvement of forage and fine turf grasses appear most promising in
the following respects:
1. Yield and viability of seed.
2. Disease resistance.
3. Ability to compete successfully with other plants.
4. Increased vigor and ability to renew growth quickly after de-
foliation.
5. Longevity, drought resistance, and winter hardiness.
6. Tolerance to wet or saline soils.
7. Palatability and nutritive value of herbage.
8. Quality, durability, and uniformity of texture in turf.
1048 YEARBOOK, 1937
Increasing Yield and Viability of Grass Seed
Many valuable grasses are notably shy seed producers. This is
especially true of our native grasses, but it also applies to many of the
introduced grasses. The failure to produce viable seed in sufficient
quantity to supply the demand is a great handicap and often prevents
an otherwise valuable grass from being grown on an extensive scale ; it
prohibits a wide use of native grasses in regrassing abandoned farm
land in the Western States; for example, the gramas, buffalo grass,
big bluestem and little bluestem, wheatgrass, and several other species
would be seeded on millions of acres of these lands if good, germinable
seed were available in commercial quantities. The same thing is true
of many of the promising introduced grasses. Woolly fingergrass from
South Africa gives indication of being an outstanding pasture grass
for the poor upland soil of the Southeastern States, but it produces little
or no seed. The Japanese lawngrass (Zoysia japonica) appears to be
exactly the kind of grass needed for sodding airports and athletic fields.
It forms a tough, long-lived turf, which would endure rough usage
and be more or less permanent. Here again seed production is negli-
gible. Good seed of Dallis grass, Bahia grass, and centipede grass
is scarce, and the use of these valuable pasture and lawngrasses is
therefore limited .
Production of Disease-Resistant Strains
While diseases are not usually so destructive to the forage grasses
as the rusts and smuts of cereal crops, there are several that present a
definite handicap to the effective use of these grasses in certain local-
ities. Sudan grass, immensely valuable in dry regions, is almost
worthless in the humid portion of the United States from Washington,
D. C, south to Florida, because of the ravages of foliage diseases.
Ergot is the chief factor limiting the production of Dallis grass seed.
A leaf-spot disease causes widespread damage to Kentucky bluegrass
in pastures and lawns. Grass diseases are most feared, however, in
the growing of fine turf on golf courses and lawns. Under certain
conditions diseases like brown patch are the greatest menace to the
fine turf grasses, especially bentgrass as it is grown and handled on
the putting greens of golf courses and on lawns. Control of diseases
of fine turf is possible through the application of fungicides, but the
development of resistant strains or varieties is preferable. In the
case of pasture and meadow grasses, the use of fungicides is not prac-
tical, and breeding for disease resistance is the only logical means of
overcoming the difficulty.
Regulating Aggressiveness by Breeding
Most of our cultivated cash crops are grown in pure stands and
occupy the land for only 1 year. Aggressiveness or ability to compete
with weeds and other plants is not, therefore, a factor of any impor-
tance in these crops. With perennial grasses, however, the ability to
retain possession of the soil to the exclusion of weeds and less desirable
grasses is a characteristic of major importance in permanent pastures.
In breeding grasses aggressiveness is a character that must be regu-
lated. If it is too pronounced the grass becomes difficult to eradicate;
MISCELLANEOUS GRASSES 1049
this is true of quackgrass and Bermuda grass. Another disadvan-
tage of pronounced aggressiveness is the difficulty of growing legumes
in combination with such grasses. In pastures and hay meadows
also, a mixture of grasses and legumes is desirable not only because of
the higher nutritive value of the mixtures but also from the stand-
point of benefiting the soil. Carpet grass and centipede grass under
favorable soil and climatic conditions produce so close a turf as to
drive out all the clovers and lespedezas that may have been seeded
with them. Bromegrass in the Dakotas and southern Canada has
been condemned by some because of its tendency to become sod-
bound and because it reappears in a field that has been plowed for the
production of a cash crop. Thus in some cases breeding methods
must be used to reduce aggressiveness and in others to increase it.
Increased Vigor and Quick Renewal of Growth
After Defoliation
The ability to renew growth quickly after defoliation is important.
Grasses are of low value in pastures or on ranges unless they are able
within a reasonable time to replace by new growth the herbage re-
moved by the grazing animal. Our best hay plants, such as alfalfa,
are high producers because, after cutting and removing one crop of
hay, new shoots appear immediately and grow as rapidly as the origi-
nal stems, thus providing from two to eight cuttings a year. Among
the grasses Sudan grass is a conspicuous example of a hay and pasture
plant that comes back quickly after being cut or grazed. The extent
and rapidity of growth in all plants is of course limited by soil and
climatic conditions. Without a productive soil and adequate mois-
ture supply either through rains or irrigation, continued luxuriant
growth throughout the growth season is impossible. Fundamental
differences however occur in the growth habits of plants that deter-
mine their behavior when clipped or grazed. Grasses that do not
continually produce new growing points low down near the surface or
underneath the surface of the soil are useless for lawns or golf courses
because the turf becomes stubbly after it is clipped a few times. Hay
plants that do not have a succession of buds at the crown capable of
producing new shoots seldom produce more than one hay crop each
season. The variation in these essential growth habits within a single
species is marked and presents a good opportunity for improvement
by selection processes.
Persistence or Longevity Fundamental
in Pasture Grasses
Longevity under grazing conditions may be less important in the
future than it has been in the past because of the present tendency to
appreciate and demand high production in pastures. However, there
will always be a large percentage of livestock producers who are willing
to accept mediocre production from pastures and ranges in return for
the assurance that this production level will continue indefinitely and
reseeding will not be necessary. In some localities, like the semiarid
regions, where the establishment of a satisfactory grass cover is
difficult or highly uncertain, permanency may be the controlling factor
in choosing a grass. Several factors such as drought resistance and
138904°— 37 07 ++
1050 YEARBOOK, 1937
winter hardiness have an important bearing on the longevity of a grass.
In breeding, therefore, longevity must be considered as a complex of
several factors rather than a single one.
Drought resistance in plants has been the subject of much study in
the arid and semiarid regions. It is not due to a simple Mcndelian
factor inherited as a unit character. Breeding for increased drought
resistance will require a thorough understanding of the elements in
plant composition and structure that enable certain plants to persist
and produce better than others under low rainfall conditions.
Tolerance to Wet or Saline Soils
In the United States considerable areas of wet lands occur. Some
of these overflow at more or less regular intervals ; other areas have a
high water table or are continually saturated by the seepage of drain-
age water from the land above them. In irrigated areas benchland
ditches often produce seepage areas in the bottom lands below them,
and such areas are frequently both wet and saline (alkaline). Poorly
drained lands in arid sections are almost invariably unproductive
because salts accumulate in the surface layer through evaporation.
Certain species of grass are known to be adapted to wet soils, and
other species are especially tolerant of soil salinity. In both cases,
however, these grasses are usually of low palatability and often of low
nutritive value. A very real need undoubtedly exists for improvement
of these grasses in palatability and nutritive value as well as for the
development of strains with increased tolerance for the abnormal
quantity of water or salts that such soils contain.
Increasing Palatability or Nutritive Value Difficult
Grasses adequate as forage for farm animals must be both palatable
and nutritious. To increase either the palatability or nutritive value
of a grass is perhaps the most difficult of all the breeding problems.
The qualities that make a grass palatable are little understood, and
the variations in nutritive value as indicated by chemical composition
are slight within any one species. There is, therefore, little encour-
agement to attempt an improvement in these fields except by
hybridization.
Quality, Durability, and Uniformity
in Turf Grasses
Considerable success has already been achieved in selecting strains
of bentgrasses that meet the special needs of the golfing public. For
the putting greens of golf courses both fine texture and uniformity are
required (fig. 12); otherwise the path of the putted ball will be un-
certain. Disease resistance, longevity, and aggressiveness are factors
of great importance on both golf courses and lawns in order that the
turf may be permanent and free of weeds and weedy grasses.
On athletic fields and playgrounds, and especially on airports, dura-
bility is the first consideration. A satisfactory turf for such purposes
must be able to withstand the tearing and gouging of cleated or spiked
shoes and the terrific impact of the landing gear on airplanes. To do
this the grass must be deep-rooted and tough and also able to cover
quickly gashes made in this way with spreading stolons or rhizomes.
MISCELLANEOUS GRASSES
CURRENT BREEDING WORK, ITS OBJECTIVES
AND RESULTS
1051
Selective Breeding of Grasses in the United States and Canada
Replies to questionnaires on grass breeding submitted to various
agricultural institutions reveal the fact that selection for improve-
ment is under way with a large number of grasses other than timothy.
Limited and more or less desultory activities in this field have been
in progress for 16 years or more, but organized and intensive grass-
breeding activities, for the most part, have been inaugurated within
the last 5 years. The various grasses included in the current selective
breeding programs of State and Federal institutions in the United
States and Canada are listed in table 2. It is apparent that a consider-
able number of workers are now concerned in developing superior
pasture and turf grasses. The results accomplished by selective
breeding in foreign countries other than Canada are not discussed in
Figure 12. — A turf plot of Metropolitan bentgrass illustrating the line texture and
uniformity required for the putting greens of golf courses.
1052
YEARBOOK, 1937
detail because of the limitations of space and the fragmentary informa-
tion obtained in response to the questionnaires. We have also to
consider the fact that very few of the improved strains of grasses
developed in Europe, Australia, or New Zealand have shown out-
standing value in the United States. In Canada, however, the
species under investigation are the same as those in the United States
| CANAO'AH AGRICULrui
Figure 13. — Locations of experiment stations in the United Slates and Canada where
organized grass-breeding work is in progress.
and climatic conditions are similar to those in our Northern States,
hence results there should be helpful to our plant breeders. The
locations of experiment stations in the United States and Canada
where organized grass-breeding work is in progress are shown on
the map in figure 13.
Improved or Elite Strains Developed by Selection
In the United States very few improved strains have yet been intro-
duced into cultivation, but notable progress has been made, especially
in the fine-turf grasses. The new strains already introduced, or soon
to be ready for introduction, include:
Washington and Metropolitan bent grass: These two strains of
creeping bent grass developed by the green section of the United
States Golf Association have replaced other grasses on a large per-
centage of the putting greens of golf courses throughout the country.
MISCELLANEOUS GRASSES 1053
The fact that these turf grasses, when used on putting greens, are
usually propagated vegetatively makes it easy to keep the strains pure
and preserve their identity.
Velvet bent grass, strain F. C. 14276: This has shown marked
superiority over the ordinary strain of velvet bent grass in vigor,
disease resistance, and quality of turf.
Promising turf strains of Poa pratensis and P. trivialis have also
been developed by the green section of the United States Golf Asso-
ciation, but these are not yet ready for distribution.
H. A. Schoth, of the United States Department of Agriculture,
cooperating with the Oregon Agricultural Experiment Station at
Corvallis, Oreg., has several improved strains ready for distribution.
Highland Reed canary grass: This is definitely superior on upland
soils; it is a heavy seed prodxicer, and the seed shatters less freely
than that of the ordinary strain. Seed of this improved strain is now
being produced and marketed commercially.
Tall fescue, strain F. C. 29366: This has softer or less harsh leaves
than the ordinary tall fescue and in general improved quality of
foliage and bettei seeding habits. Seed production of this tall
fescue will be on a commercial basis in 1937.
Tall oatgrass, strain F. C. 29367: The fault of seed-shattering charac-
teristic of this species has been remedied almost completely. In this
strain the seed increase is just in the initial stages, so that it is not
ready for commercial distribution.
Bahia grass, strain F. C. 19774: A selection made in 1929 by F. H.
Hull, associate agronomist, Florida Agricultural Experiment Station,
Gainesville, Fla., on the basis of stigma color has proved definitely
more resistant to the helminthosporium loaf disease than the ordinary
strain. This selection has been compared with the common strains
of Bahia grass by George E. Ritchey, of the United States Department
of Agriculture, at the Florida station. Arrangements are being made
to increase the seed of it in Arizona as a source of commercial seed
production.
Tift Bermuda grass: A vigorous, fine-stemmed strain selected by
J. L. Stephens, of the United States Department of Agriculture, at
the Georgia Coastal Plain Experiment Station, Tifton, Ga. This
strain is much more productive as a hay plant than the common Ber-
muda grass. In 1936, when 400 pounds per acre of complete fertilizer
were applied, 2 tons per acre of fine quality hay were obtained in two
cuttings. In the past it has been propagated vegetatively, since
Bermuda grass does not produce viable seed in Georgia, at least in
any quantity.
Reed canary grass, Iowa 503: This was selected by H. D. Hughes
and F. D. Wilkins, agronomists at the Iowa Agricultural Experiment
Station, from the progeny of seed sent to them by an Iowa farmer in
1918. The strain produces high yields of both hay and seed and
appears valuable also in pastures because it makes a rather dense turf
and remains green late in the fall. It was distributed to farmers in
1930 under the name Iowa Phalaris.
In Canada, where agricultural workers have devoted more attention
to breeding problems, a considerable number of improved forage and
1054
YEARBOOK, 1937
turf strains have been developed and are now in commercial produc-
tion. Among those reported by Canadian workers are the following:
Grazier slender wheatgrass: A leafy uniform strain that produces
a high yield of pasturage and hay. Developed by G. P. McRostie
and L. E. Kirk at the Central Experimental Farm", Ottawa, Ontario.
L. E. Kirk, before his removal to Ottawa, and T. M. Stevenson,
working at the Dominion Forage
Crops Laboratory, Saskatoon,
Saskatchewan, developed four
elite strains or varieties, namely:
Mecca slender wheatgrass: A high-
yielding hay variety.
Fairway crested wheatgrass: A
rather dwarf, fine-stemmed, leafy
strain that usually produces lower
yields of hay than ordinary crested
wheatgrass but is superior to the lat-
ter for use on lawnsandon the fairways
of golf courses. Already the Fairway
strain has a wide use in the west-
ern parts of the United States and
Canada.
Superior bromegrass: This was de-
veloped by Kirk from material col-
lected by J. Bracken prior to 1921.
It is now definitely established as a
high-yielding hay and pasture variety.
Parkland bromegrass: Character-
ized by a reduced rhizome develop-
ment that makes it to all intents and
purposes a noncreeping variety. Park-
land bromegrass does not become sod-
bound so quickly as ordinary brome-
grass and is less difficult to eradicate
when grown in rotation with culti-
vated crops.
Fyra slender wheatgrass: This
was developed by M. O. Malte
and G. H. Cutter at the Uni-
versity of Alberta, Edmonton, Alberta, as an improved hay variety.
Avon orchard grass: Developed by workers in the Agronomy Depart-
ment of MacDonald College at Quebec, this strain had its origin in foun-
dation stock introduced by L. S. Klinck, 1911-14. Sel fed lines were iso-
lated by L. A. Waitzinger, G. P. McRostie, and A. MacTaggart in the pe-
riod 1914-30, and J. N. Birdin subsequent years has combined the most
promising of these genotypes to form the strain called Avon. The Avon
is decidedly more winter-hardy and therefore longer lived and produces
larger yields of hay and aftermath than commercial orchard grass. In-
creased seed production of the Avonis in progress at MacDonald College.
In addition to the named strains herein credited to Canadian
breeders, O. McConkey (fig. 14) and his associates at the Ontario Agri-
cultural College, Guelph, report (Y. B. Q.)9 that 23 improved strains
of grasses are being increased for more extended trials and distribu-
tion at Guelph. These include the species listed for Guelph in table 1.
1 This abbreviation will he used in the following pages to indicate that the informal ion was received in
reply to the Yearbook questionnaire, sent out in the cooperative survey of plant and animal improvement.
Figure 14. — O. McConkey, associate pro-
fessor, Department of Field Husbandry,
Ontario Agricultural College, Guelph, On-
tario, Canada, who, with L. E. Kirk, of
Ottawa, has pioneered in grass-breeding
investigations in Canada.
MISCELLANEOUS GRASSES
Reservoirs of Plant Material for Selection
1055
The most important sources of material for selection are, of course,
the ranges, pastures, and meadows where grasses have been estab-
lished for a good many years. From this primary source and from
foreign lands the United States Department of Agriculture in co-
operation with State experiment stations has brought together for
Figure 15. — Grass nursery maintained by the Bureau of Plant Industry and the Soil
Conservation Service of the United States Department of Agriculture at the Northern
Great Plains Field Station, Mandan, N. Dak. Side-oats grama in the middle
foreground.
comparison in grass nurseries extensive collections of native and
introduced species. Seed of all the more important native grasses
was collected by the Soil Conservation Service in 1935 and 1936
throughout the arid and semiarid Western States. Seed or propagat-
ing material of foreign species has been obtained through the Division
of Plant Exploration and Introduction of the Bureau of Plant Industry
for many years, and these and the native species are available to
plant breeders in nurseries (fig. 15) maintained at field stations of
the United States Department of Agriculture and at State experiment
stations and substations where cooperation with the United States
Department of Agriculture exists. Such cooperation is indicated in
table 1.
Selective Breeding in Foreign Countries
Other Than Canada
Breeding work with grasses has been developed much more in. the
British Isles, New Zealand, Australia, Sweden, Germany, and Den-
mark than in the United States.
The Imperial Bureau of Plant Genetics, Aberystwyth, Wales, has
made the greatest contribution in the work on herbage grasses,
under the direction of R. G. Stapledon. The technique for producing
and distributing improved strains of grasses that has been developed
1056
YEARBOOK, 1937
by Stapledon and his associates, especially T. J. Jenkin (fig. 16),
should be very helpful in formulating a program for similar work in
the United States. It is described fully in a publication of that
bureau (11).
The results achieved in the British Isles and New Zealand also
provide proof of the practical value of a comprehensive grass-
breeding program. Levy (18)
agrostologist, New Zealand De-
partment of Agriculture, reports
progress in the use of improved
strains of perennial ryegrass as
follows: "The North Island is
using over 95 percent certified
(seed) and it is difficult to
dispose of uncertified at any
price."
While the work at the Welsh
Plant Breeding Station and in
New Zealand is perhaps most
outstanding, excellent breeding
work has long been under way
at the Northumberland County
Agricultural Experiment Station
at Cockle Park near Newcastle,
England; at the Scottish Plant
Breeding Station near Edinburgh,
Scotland, and in South Africa
and Australia. F. Nilsson and
A. Muntzing, of the Seed Control
Station, Swedish Seed Associa-
tion, Svalof, Sweden; H. Weller,
Weihenstephan near Munich,
Germany; and H. N. Frandsen,
Stoftegaard, Denmark, are also
making valuable contributions
in grass improvement and breed-
ing technique.
The map in figure 17 gives the locations of foreign grass-breeding
stations. _ „ _
Progress in Hybridization of Grasses
Improvement by selection within a species or variety is usually the
first step in a breeding program. In every crop, however, the plant
breeder ultimately resorts to hybridization as a means of inducing
greater variation and also in order to combine in one plant the desir-
able characters found in different species or genera of plants. The
question of how soon hybridization should become a part of a breeding
program is not an easy one to answer. Many believe crossing of
species and genera should not be undertaken until the possibilities of
improvement, by selection have been virtually exhausted and approxi-
mately pure lines have been obtained for use as parents of the cross.
Several potent reasons exist for earlier use of this effective method of
plant improvement: (1) To wait until the possibilities of selection
Figure 16. — T. J. Jenkin, who is associated
with R. G. Stapledon at the Welsh Plant
Breeding Station and has made many im-
portant contributions to the science and art
of grass breeding. He is responsible for
the breeding of all grasses except orchard
grass and for the development of a breeding
technique.
MISCELLANEOUS GRASSES
1057
are exhausted would delay hybridization benefits almost indefinitely ;
(2) strains developed by hybridization usually show more marked
difference from the ordinary strain than do selections and are therefore
easier to identify and keep pure in commercial trade channels; and
Figure 17. — Locations of the principal grass-breeding stations in the Eastern Hemi-
sphere: 1, Welsh Plant Breeding Station, Aberystwyth, Wales; 2, Northumberland
County Agricultural Experiment Station at Cockle Park, near Newcastle, England;
3, Scottish Plant Breeding Station, near Edinburgh, Scotland; 4, BJjksstation voor
Plantenveredeling, Ghent, Belgium; 5, Landessaatzuchtanstalt, Weihenstephan, near
Munich, Germany; 6, Danish Plant Breeding Station, Stoftegaard, Denmark; 7, Seed
Control Station, Swedish Seed Association, Svalof, Sweden; 8, Institute of Plant
Industry, Leningrad, Union of Soviet Socialist Republics; 9, Institute for Fodder
Crops, Moscow, Union of Soviet Socialist Republics; 10, Central Asia Scientific
Research Institute of Plant Protection, Tashkent, Union of Soviet Socialist Republics;
11, Waite Agricultural Research Institute, Adelaide, Australia; 12, Commonwealth
Council for Scientific and Industrial Research, Canberra, Australia; 13, Plant
Research Station, Department of Agriculture, Palmerston North, New Zealand; 14,
Canterbury Agricultural College, Lincoln, Canterbury, New Zealand; 15, Prinshof
Pasture Research Station, Pretoria, South Africa.
(3) the intelligent combining of desirable traits, such as disease-
resistance, with good forage characters, is often possible by crossing.
Breeders have successfully crossed many species of grasses and in
several instances have been able to combine closely allied genera.
For the information of present and future workers in this field the
hybrids between species are fisted in table 3 and the hybrids between
1058
YEARBOOK, 1937
genera in table 4 in the appendix. It will be noted that a large pro-
portion of these hybrids are the products of foreign workers, Russian
plant breeders having been especially active in this field. A number
of the hybrids are combinations of the relatives of wheat and rye.
\
Figure 18. — TrUicum-Agropyron hybrid produced by W. J. Sando, United States
Department of Agriculture, showing the hybrid vigor attained in the first generation.
From left to right, Agropyron elongatum, hybrid, Trilinim aestivum.
MISCELLANEOUS GRASSES
1059
Some of these, especially the Triticum-Agropyron hybrids, appear to
have marked forage value (fig. 18). Sando, of the United States
Department of Agriculture, and Armstrong, of the Canadian Depart-
ment of Agriculture, who have had an opportunity to observe such
hybrids, are convinced that many of the segregates of these crosses
Figure 19. — A few of the variants found in the (irst-generation hybrid of a cross Poa
arachnijera X pralensis: A, Texas bluegrass type; B, C, and D, intermediate types,
C, being one of the less desirable; E, Kentucky bluegrass type.
1060 YEARBOOK, 1$37
will have great value from a forage standpoint. Armstrong (1) states
in his report: "Their [the Russian plant breeders] chief aim has been
the creation of new forms of perennial wheat. For Canadian condi-
tions the possibilities of obtaining new forms of forage crops by this
method appear more attractive." Arrangements are now being made
by the United States Department of Agriculture to study the forage
value of Sando's crosses.
Jenkin, of the Welsh Plant Breeding Station, has successfully
crossed the two genera Festuca and Lolium and has also made many
hybrids among the species within these genera. Brief notes on the
progeny characters of these hybrids will be found in tables 3 and 4.
No new strain of superior value has resulted from these crosses to
date, and Jenkin reports that more immediate improvement in forage
'
K
y
[ /
K f
|
■Wml
Hrf-j
m
Mr ' tbB
ft'
■H?' -JaBr v,MH
■Bt V
^m
''-■. '
Figure SO. — Single plants representing the various types found in the first generation
of a cross Poa arachnifera X pratensis. These plants were grown on the United States
Department of Agriculture grounds in 1909 from seed of crosses made by George W.
Oliver the previous year.
value can be attained through selection within a species than in the
progeny of the crosses he has made.
This evidence of the futility of hybridization methods cannot be
accepted as final, however. In many instances repeated backcrossing
has been found necessary to produce the desired types. Muntzing,
of the Swedish Seed Association, found in the progeny of a backcross
(Dactylis glomerataxaschersonianaxglomerata) individuals more vigor-
ous than D. glomerata. Texas bluegrass (Poa arachnifera) is dioecious,
having the male and female spikelets on different plants. Using the
pistillate plants as the female parent, E. Marion Brown, of the United
States Department of Agriculture, made crosses of this species and
Kentucky bluegrass at Columbia, Mo. He reports wide variation
(fig. 19) in the first-generation plants, including individuals more
resistant to heat and drought and more productive than Kentucky
bluegrass. This cross was made first in 1908 by the late George W.
Oliver. Oliver also found an unusual degree of variation (fig. 20)
in the first-generation hybrid of this cross, but there was little interest
in grass breeding at that time and nothing came of it. These results,
in addition to the observed forage value of the Triticum-Agropyron
hybrids, encourage further hybridization efforts.
MISCELLANEOUS GRASSES
1061
GRASS GENETICS AND HYBRIDIZATION TECHNIQUE 10
To achieve the utmost possible success in breeding within any group
of crop plants, a thorough understanding of the genetics of the plant
species is necessary. It is a fact that a large number of the improved
varieties that find their
way into commercial chan-
nels are produced by the
selection of existing vari-
ants or by breeders who
consciously combine the
desirable qualities of sev-
eral varieties or species by
crossing or hybridizing
them without having any
definite knowledge of the
manner in which the desir-
ed character is inherited.
The genetic analysis of
any species of plants or
animals is extremely slow
work, and many of the
results obtained have no
practical application. In-
dividuals who accomplish
most in the realm of pure
genetics are not likely to
be concerned overmuch as
to whether new and im-
proved crop varieties re-
sult directly from their
research. Practical plant
breeders are, however, im-
patient of delay and usual-
ly proceed without know-
ing quite what to expect in
the progeny of a hybrid
but fully convinced that
something good will be
found in the segregates
if the parents of the cross
have been intelligently
chosen. With the grasses
as with corn and wheat
the more or less unscien-
tific breeding operations
have preceded the genetic
investigation. Henceforth
the two phases of breeding
will no doubt progress to-
10 The following section is intended pri-
marily for studentsand others profession-
ally interested in genetics or breeding.
Figure 21. — Phalaris truncata, a foreign relative of
the reed canary grass having a spikelike panicle.
Note the progress of blooming from apex to base.
Panicle on left began to bloom 2 days earlier than
that on the right.
1062
YEARBOOK, 193 7
gether. As specially trained groups of geneticists become interested
in the study of forage grasses, the fund of basic information regard-
ing their genetic constitution will increase rapidly. At present it is
most inadequate. We do, however, have some knowledge of certain
characteristics of our more important grasses that are useful in
genetic studies. These
will be discussed
briefly.
Flowering Habits
of Grasses
The inflorescence or
flower-bearing organ
of grasses may be a
compact spikelike pan-
icle as in canary grass
or a more or less loose
panicle as in orchard
grass or bluegrass (figs.
21 and 22). Regard-
less of the type of in-
florescence, flowering
begins near the apex
of the inflorescence
and progresses more
or less regularly to-
ward the base. In the
spikelet the reverse is
true; the basal florets
open first, followed in
regular order by those
above. Through the
courtesy of Mrs. Agnes
Chase, of the Division
of Plant Exploration
and Introduction,
Bureau of Plant In-
dustry, the essential
floral organs, the floral
envelope, and the ar-
rangement of florets
in the spikelet are
shown in figure 23.
Grasses flower, that
is, extrude their sta-
mens and liberate
pollen, most abun-
Figure 22. — Flowering pan-
icle of Kentucky blue grass,
illustrating the loose, open
type of inflorescence found
in many grasses.
MISCELLANEOUS GRASSES
1063
dantly in the early morning. This is an almost universal rule (S),
although the period of flowering may be delayed and prolonged
by cloudy atmospheric conditions. For several grasses at least
there is apparently a secondary, less intensive anthesis period in the
afternoon. Fruwirth (5), who from 1906 to 1915 conducted some
important and rather extensive studies of anthesis and pollination in
grasses, reports a secondary blooming period in the afternoon that
lasted only 1 or 2 hours. This work was conducted at Hohonheim
and Waldhof, near Amstettin, Germany. Sando u found in Agro-pyron
elongatum the maximum anthesis between 6 and 8 a. m., but there
FILAMENT
LOOICULES
^4 & C
Figure 23. — A grass inflorescence is composed of spikelets, florets, and flowers: A,
Generalized spikelet indicating the alternate arrangement of florets on the rachis and
relative positions of the glumes; B, grass floret opened as at blooming time, showing
how the lemma and palea are forced open by the lodicules;. C, typical grass flower
showing the essential floral organs necessary in fertilization.
was another period of activity between 3 and 4 p. m. "No blooming
occurred between 8 a. m., and 3 p. in." Sando also reports that
blooming is most active when the sun is shining and the temperature
70° F. or above. No blooming was ever observed at temperatures
below 52°. He believes the delay or reduction in anthesis caused by
a cloudy sky is due more to the lowering of temperatures than to
increased humidity.
The views of Sando respecting the effect of humidity are confirmed
by the studies of Stephens and Quinby (.29) on sorghum (Sorghum
vulgar e). They concluded, "Relative humidity apparently did not
influence the time of blooming." Since sorghum is a grass, it is
interesting to note that under field conditions at Chillicothe, Tex.,
the rate of blooming in the sorghums was highest shortly after mid-
night rather than in the early morning as Sando found for bis Agro-
pyron and Triticum species growing in the greenhouse. Although the
hour of maximum blooming activity in sorghum varied with varieties,
Stephens and Quinby state, "A relatively small proportion of flowers
opened before 10 p. m. or after 8 a. m., but there were no hours in
which flowers were never found opening." By placing plants in a
dark room during the day and exposing them to artificial light at
" Personal correspondence, 1936.
1064 YEARBOOK, 1937
night the natural rhythm of blooming was reversed in 36 hours. It
would appear, therefore, that light conditions are a most important
factor in governing the time of blooming. They found, however, that
lowering the temperature reduced the rate of blooming.
Fruwirth (5) agrees with Stephens and Quinby regarding the effect
of humidity but not as to light. In an experiment with ryegrass and
orchard grass in which he placed a box lined with black paper over
the plants to exclude all light rays, he found that the plants bloomed
in spite of the lack of light. He concluded from this experiment in
which the heat was sufficient but light was lacking, that the latter
seemed to be unnecessary for blooming. There is one criticism to be
made of this experiment in that Fruwirth did not alternate darkness
and light but left the box in place day and night. Recent investiga-
tions have emphasized the importance of the relative proportion
of daylight and darkness in the reproduction processes of plant
development.
Wolfe (38) in his studies of orchard grass at Blacksburg, Va.,
observed 76.9 percent of the flowers blooming from sunrise to noon,
6.6 percent from noon to sunset, and only 0.3 percent from sunset to
midnight. The maximum blooming occurred from 8 to 9 a. m.
Jenkin (9) in 1921 observed for several grasses the time on "very
fine days" when anthers were exserted under cool greenhouse condi-
tions. These residts show that the greater part of the blooming takes
place in the forenoon. His recorded observations were as follows:
LoliiMii perenne. — Blooming period 9 a. m. to 11 a. m.; maximum 9:15 to 9:30
a. m.
Fesluca rubra. — Blooming period 9:45 a. m. to 2:30 p. m.; maximum 12 to 1
p. m.
Alopecurus pralensis. — Blooming period 6 to 7:45 a. m.; maximum 6:30 to 7:30
a. m.
Phalaris arundinacea. — Blooming period 5 to 10:15 a. m.$ maximum 6 to 6:30
a. m.
The author does not state in what month these observations were
made. He does say, however, that in the open "these species appar-
ently flower rather earlier while in dull weather in the greenhouse
anther exsertion may be considerably delayed and * * * may be
very poor for several days." Jenkin found that orchard grass, tall
oatgrass, and timothy, unlike the perennial ryegrass and red fescue,
begin blooming early in the morning.
Self-Fertility in Grasses and its Relation to
Effect of Inbreeding
The fertility of many important grass species has been summarized
in great detail by Beddows (3), of the Welsh Plant Breeding Station,
who made a thorough review of the literature on this subject. He
found that as a general rule the annual grasses were "highly self-
fertile", but the perennials showed a high degree of self -sterility.
Exceptions occurred however, in both cases, and in certain species
there was a marked variation in respect to this character within the
species. Nilsson (21), of Sweden, made a detailed study of fertility
and the effect of inbreeding in meadow fescue, orchard grass, and
timothy. As would be expected, the effect of close fertilization or
MISCELLANEOUS GRASSES 1065
inbreeding varies in different species according to whether they are
naturally cross-fertilized or self-fertilized. The situation regarding
these characters as they affect a few of our more important grasses
will be found useful in breeding by either selection or hybridization
methods.
Orchard grass or cocksfoot . (Dactylis glomerata): Stapledon (27)
found D. glomerata normally setting much more seed when cross-
fertilized than when self -fertilized, but containing "representative
plants wliich are highly self-fertile." These results have been con-
firmed by breeders in the United States and Canada. Stapledon
says, "There is every reason to suppose that completely self-fertile,
single plant lines could be isolated." Regarding loss of vigor from
inbreeding he concludes that on the average selfed plants are about
half as vigorous as plants produced by crossing. He found, however,
certain "robust" plants that showed little loss in vigor when selfed for
five generations. There is, therefore, an opportunity to use inbreed-
ing methods on this species to purify lines.
Perennial ryegrass (Lolium perenne): Jenkin (10) and Gregor (7)
report a low degree of self-fertility in L. perenne, but great variation
between plants in tins respect. Some plants were completely male-
sterile while others were comparatively self -fertile, so that Jenkin (10)
concludes "breeding for self -fertility would not be a difficult matter"
in perennial ryegrass. Beddows (3) reports 3.6 times as much seed
produced in open-fertilized as in close-fertilized plants.
Loss of vegetative vigor resulting from continued inbreeding of
unselected perennial ryegrass plants is extreme. Jenkin (11) reports
an average loss of vigor approximating 63 percent when plants were
selfed or fertilized with pollen from other plants of the same line. He
concludes, "In perennial ryegrass loss of vigor from selfing is extreme,
and consequently the results from other forms of inbreeding will
also be relatively pronounced." Wenholz and Whittet, of Australia
(Y. B. Q.), confirm Jenkin's results and have discontinued the practice
(selfing) in breeding perennial ryegrass.
Italian ryegrass (Lolium muUiflorum): The conditions regarding
self-fertility and loss of vegetative vigor are about the same in Italian
as in perennial ryegrass.
Crested wheatgrass (Agropyron cristatum): White (Y. B. Q.), of
Saskatchewan, reports that sterility is very marked in caged or bagged
plants, although this evidence of self-sterility is not conclusive. He
found also a large decrease of vegetative vigor in close-fertilized plants,
which indicates a low degree of self-fertility.
Slender wheatgrass (Agropyron pauciflorum): Malte (19), of the
Central Experimental Farm, Ottawa, Ontario, Canada, reported in
1921 that A. pauciflorum (A. tenerum Vasey) was self -fertile, and
White (Y. B. Q.) found this species almost completely self-fertile and
showing no loss in vegetative vigor from continued selfing. This
condition presents a strange contrast to the behavior of A. cristatum.
Beddows (8), of Wales, agrees with White, finding both A. repens and
A. pauciflorwm highly self-fertile.
Bentgrass (Agrostis spp.): North (Y. B. Q.), formerly of Rhode
island, reported A. alba (redtop) somewhat more self-fertile than
A. tenuis (colonial bent), A. canina (velvet bent), or A. palustris
1!S8904°— 37 08
1066 YEARBOOK, 1937
Huds. (creeping bent). All of the Agrostis species showed a tendency
toward loss of vigor from continued selfing although only a few
generations were obtained.
Smooth bromegrass (Bromus inermis): White (Y. B. Q.) reports
self-sterility "fairly marked" in bromegrass, but adds that there is
a wide variation between plants. If. this variation exists it would
admit of the development of reasonably self-fertile strains. Beddows'
(8) results show a very high degree of self-sterility in B. inermis,
but very little in B. catharticus (B. unioloides) and other annual
bromes. White also reports a marked and progressive loss in vegeta-
tive vigor from selfing for four or five generations. This loss of vigor
from selfing is confirmed by McConkey (Y. B. Q.), of the Ontario
Agricultural College.
Reed or tall fescue (Festuca elatior var. arundinacea): Beddows
(8) found 5.1 times as many seeds developing in open-pollinated as in
close-pollinated inflorescences. Govaert (Y. B. Q.), of the Rijksstation
voor Plantenveredeling, Ghent, Belgium, reports a wide variation
between individual plants, some being almost completely self-fertile.
Meadow fescue {Festuca elatior var. pratensis): According to
Beddows (8), the meadow fescue is more self-sterile than the tall
fescue. Open-pollinated panicles gave 22.3 times as many seed as
the close-fertilized ones. As in the tall fescue, however, Govaert
(Y. B. Q.), of Belgium, found a wide variation in individual plants,
the number of seeds on different plants varying from an average of
less than 1 to 409 per inflorescence. There would seem, therefore,
to be an opportunity here to select self-fertile strains. G. Nilsson-
Leissner (Y. B. Q.), at the Swedish Seed Association, Svalof, Sweden,
found cases of complete self-sterility in meadow fescue and a marked
loss of vigor after repeated selfing.
Red fescue (Festuca rubra): Beddows (Y. B. Q.) found the self-
fertility in red fescue about as low as in tall fescue, selfed plants
producing about one-fifth as much seed as those open-pollinated. G.
Nilsson-Leissner (Y. B. Q.), of Svalof, found cases of complete self-
sterility and a marked loss of vigor caused by selfing, as he had in
meadow fescue.
Canada bluegrass (Poa compressa): McConkey (Y. B. Q.), of the
Ontario Agricultural College, reports this species largely self-fertile.
Under such conditions there is probably very little decrease in vegeta-
tive vigor caused by selfing.
Kentucky bluegrass {Poa pratensis): A considerable number of
plant breeders and cytologists have studied this important grass and
found it unusually interesting from two angles — there is a wide
variation in the number of chromosomes, and seed is produced, to a
considerable extent at least, apomictically. Musser (Y. B. Q.), of
Pennsylvania, Brown (Y. B. Q.), of Missouri, and others report no
self-sterility in Kentucky bluegrass and no apparent loss of vigor
from selfing.
Sudan grass {Sorghum vulgare var. sudanense): Sudan grass, a
close relative of the cultivated sorghums, is self-fertile. Robertson
(Y. B. Q.), of Colorado, reports no apparent loss of vigor after three
generations of selfing. Wenholz (86, p. 88), of New South Wales,
reports loss of vigor in some lines under continued inbreeding.
MISCELLANEOUS GRASSES 1067
Fruwirth (5) reports a method of overcoming the handicap of
self-sterility in the perennial grasses that may be of great value to
plant breeders. He divided the clump or tuft that had developed
from a single seed and grew these parts of the same plant to maturity
in separate pots or boxes. When these individual plants wore isolated
as a group and allowed to bloom freely and interpollinate each other, con-
siderable viable seed was produced. There were, however, some cases
where this method was not successful. With "French ryegrass" no seed
was obtained, and Fruwirth concluded that these plants were completely
self -sterile. „ 0 ,T
SELF-STERILITY IN HYBRIDS
Self-sterility, or more properly male-sterility, in the F! of inter-
specific and intergencric grass hybrids is quite common (table 4) . In
many cases there is variation in the degree of sterility among indi-
viduals, but in most cases backcrossing is required to produce seed.
The number of self-fertile segregates increases with repeated back-
crossing, which is an accepted procedure among breeders who arc
laboring to produce new varieties of value in practical agriculture.
In some cases polyploidy is induced and increased vigor obtained by
crossing the hybrid with a third species.
Verushkine (35) reports that in general the fertility of the hybrids
of Triticum and Agropyron exceed considerably the fertility of the
rye-wheat hybrids, and that it is somewhat higher than the fertility
• of Aegilops X Triticum hybrids. He classifies the Triticum X
Agropyron hybrids into the following groups in respect to the fertility
of the first generation:
1. T. vulgare 12 X A. elongatum.
2. T. durum X A. intermedium and A. trichophorum.
3. T. vulgare n X A. intermedium and A. trichophorum.
4. T. durum X A. elongatum.
No trouble is experienced in the first group in obtaining self-ferti-
lized seed, but in the fourth group "among hundreds of plants"
Verushkine and his associates found none self-fertile.
Successful crosses of the two genera Festuca and Lolium are reported
by T. J. Jenkin (see footnotes 1 and 3, table 4), of the Welsh Plant
Breeding Station. In many cases although seed set, none of it
germinated. In other cages Fx plants were established, but these
were male-sterile. They were, however, in many cases used success-
fully as the pistillate parent in backcrosses on one of the parent species.
Chromosome Complex of Grasses
The basic chromosome number for grasses is usually seven. There are,
of course, exceptions, like that of the Sorghum species, where the basic
number is five. Cytologists have already determined the chromosome
number in a large proportion of the grass species, and their summarized
records are available to the plant breeder in several publications. The
most extensive lists of chromosome numbers in grasses are those of
Avdulow (2), Gaiser (6), and Tischler (30). In order to make such
data available to breeders in the United States, a condensed list of
reported chromosome numbers in grasses is given in tabic 5.
12 Synonym for T aestivwm.
1068 YEARBOOK, 1937
No thorough investigation of the chromosome behavior during
meiosis has been made for any of the forage grasses. A limited amount
of information is available, however, regarding valence, lagging, etc.,
of the chromosomes of certain grasses. Wide differences in the
chromosome numbers of individuals of certain species have been
reported. These chromosome irregularities naturally .affect the
behavior of hybrids and in some cases are useful factors in maintaining
the purity of selected strains. Thus in breeding orchard grass
(Dactylis glomerata) the Ontario Agricultural College (23) found the
leafy pasture strain had 14 chromosomes while the common com-
mercial strain had 28 chromosomes. Therefore the two strains do
not cross readily; each remains pure or distinct.
The pasture strain of orchard grass developed by selection in
Ontario has 14 chromosomes, the same number as the so-called wild
species Dactylis aschersoniana, according to Miintzing (20) of the
Swedish Seed Association. Muntzing found natural crosses of
D. glomerata and D. aschersoniana near Svalof, although it was found
very difficult to make this cross artificially. He found 21 chromo-
somes in the natural hybrid, and when this triploid was backcrossed
on D. glomerata the Ft had 35 chromosomes. These pentaploids
were more vigorous than ordinary orchard grass, and in their prog-
eny individuals were found having 38, 39, and even 41 chromo-
somes. Peto (24), at the University of Alberta, in his very detailed
cytological studies of the Agropyron species, reported 14 and 28
chromosome forms of A. cristatum and 21 and 28 chromosome forms
of A. pauciflorum.
Randolph (Y. B. Q.), cytologist, Division of Cereal Crops and Dis-
eases, Bureau of Plant Industry, at Cornell University, found in
Kentucky bluegrass (Poa pratensis) individuals having 48, 50, 54, 68,
and 72 somatic chromosomes. The most common number reported
for P. pratensis is 56. Practically all cytologists who have worked
with this species have noted wide variations. Since 7 is the basic
chromosome number in most grasses, if this condition is a tendency
toward polyploidy the differences should be various multiples of 7.
Randolph's results previously mentioned and those of Rancken (26)
may be explained on the basis that these indicated variations from
exact multiples of 7 are the result of the cytologists' failure to distin-
guish between whole chromosomes and fragments. These "super-
numerary chromosome fragments" Rancken reports are present in
Poa pratensis, Dactylis glomerata, Festuca elatior var. pratensis, and
Alopecurus pratensis. Chromosome fragments, Rancken believes,
may possibly act as phylogenetic factors.
A peculiar chromosome relationship found in Phalaris species is
reported by Jenkin and Sethi (15). P. arundinacea and P. tuberosa
both have 28 somatic chromosomes showing 14 bivalents in the
heterotypic mctaphase. The basic number in these species is obvi-
ously 7, but in P. canariensis the basic number is reported as 6. P.
arundinacea and P. tuberosa were successfully crossed and the Fx had
28 chromosomes, 12 bivalent and 4 univalent. Other instances of
apparent aberrant chromosome conditions are recorded by cytologists,
but those mentioned are sufficient to indicate the nature of such
abnormalities in forage grasses.
MISCELLANEOUS GRASSES 1069
The production of polyploidy or doubling of the chromosome num-
ber by means of species crosses is illustrated by the work of Nilsson
{21), Undrom, Sweden, who reports as follows: "From the hybrid
F. [Festuca] arundinacea X F. gigantea, which is highly sterile, 2 prog-
eny plants were obtained. P\ had the same somatic chromosome
number (42) as the parents, but the progeny plants differed very much,
one having the somatic number 84." This doubling of the chromo-
somes is explained to have originated by accidental intercrossing of
the J\ hybrid and a third species, F. elatior var. pratensis. Such an
explanation is said to be in harmony with the morphological char-
acters. The author claims this has resulted in "a new polyploid type
intermediate between the parents and highly fertile in comparison
with Fi."
Compatibility a Factor in Hybridization
As Ivydridization investigations progress it is apparent that there
are different degrees of compatibility not only between species but also
between varieties and even strains. Thus Armstrong (1), when using
Agropyron glaucum as the pollen parent, was 32.2 to 34.6 percent
successful with Triticum durum and T. dicoccum, respectively, as the
pistillate parents and only 6.5 to 11.7 percent successful with three
varieties of T. aestivum as the pistillate parent. Strain no. 820 of
A. elongatum crosses on emmer (T. dicoccum) resulted in 38.7 percent
success, while strain no. 1083 crossed with emmer gave only 1.5 percent
success.
Most workers have found a high degree of compatibility between
Triticum aestivum and Agropyron elon-gatum and between T. durum
or T. dicoccum and A. intermedium. A. trichophorum and A. junceum
are also said to cross readily with wheat, but no one has been
able to cross wheat with A. repens, and Sando13 reports failure in
his attempts to cross wheat and A. smithii. Armstrong (1) and other
Canadian workers have failed in their attempts to use as the pollen
parent A. desertorum, A. dasystachyum, A. caninum, A. imbricatum,
A. repens, A. cristatum, or A. richardsoni in crosses on T. durum,
T. dicoccum, or T. aestivum. These unsuccessful attempts to com-
bine the indicated species of Agropyron with the Triticum species,
while not conclusive, are evidence of incompatibility not appar-
ent from .morphological characters customarily used in botanical
classifications. The examples given of differences between species of
Agropyron and Triticum will serve to illustrate what the breeder may
expect to encounter in other genera.
Technique of Hybridization
Jenkin, of the Welsh Plant Breeding Station, has, no doubt, studied
this question to a greater extent than any other investigator. His
recommendations (9) as to the best methods of crossing grasses are
given in a bulletin published in 1924, and a later resume1 (11) of the
subject was published in 1931.
Geneticists usually agree that hand-crossing is the only method to
follow if dependable results are to be obtained, and this is emphasized
by Jenkin. He sets forth several rules to be observed in the work of
hybridization:
•3 Personal correspondence, 1936.
1070
YEARBOOK, 1937
1. No inflorescence of a species used for crossing should be allowed to flower
unprotected in the greenhouse. This is to avoid free pollen floating about.
2. All ventilators should be closed an hour or more before starting operations,
to prevent drafts and allow free pollen to settle and avoid scattering pollen that is
being collected for use in crossing.
3. Soft brushes should be used in applying pollen.
4. On both the pistillate and the pollen parent inflorescences should not be
exposed any longer than absolutely necessary.
Figure 24. — Comparative size of florets of various grasses in comparison with the
wheat floret: a, Wheat; b, smooth bromegrass; c, crested wheatgrass; d, orchard grass;
e, woolly fingergrass; /, Kentucky bluegrass. X 9. Upper right natural size.
5. Each brush should be sterilized after being used, and a sufficient number of
brushes should be available so that no brush will be used more than once a day.
Emasculation Methods and Equipment
Emasculation of all flowers left on the pistillate parent to be polli-
nated is necessary except when that parent is known to be completely
male-sterile. This operation must perforce be performed before full
bloom occurs, but it is most easily accomplished just prior to this
stage of development. In sorghums the flowers may be successfully
emasculated by immersing the inflorescence in hot water for a short
time. This method, discovered by Stephens and Quinby (28), may
perhaps be equally effective on the smaller grasses, but until the exact
temperatures required to kill the pollen on these grasses without
MISCELLANEOUS GRASSES
1071
injuring the stigmas are determined, most breeders will continue to
use the more tedious hand-emasculation method.
The process of hand emasculation in grasses is very difficult owing
to the small size of the individual florets (fig. 24). While Jenkin sug-
gests emasculating with the naked eye or with the assistance of only a
small hand lens, most breeders find magnifying instruments necessary
or at least very helpful. Instruments for this purpose should be
capable of use without
being held in the hand,
since both hands must
be free to manipulate
the flowers. Magnify-
ing glasses provided
with a contrivance to
hold them in position
on the operator's head
are preferred by some.
Others find binocular
microscopes attached
to a horizontal arm on
a vertical stand of the
proper height most sat-
isfactory for this work
(fig. 25). When the
lenses are adjusted to
a long focus there is
little interference with
the movements of the
hands and the delicate
emasculation opera-
tions may be carried
out with more assur-
ance than without such
equipment. The use
of a binocular in hy-
bridization work with
grasses was suggested
in 1934 by De Villiers
(4), research officer,
Division of Plant In-
dustry, Pretoria, South Africa. Much of his work was with the Digi-
taria species, or woolly fingergrasses, which have extremely small flower
parts (fig. 24). Emasculation of such grass flowers without magnifying
instruments is well-nigh impossible.
The technique that Sando (Y. B. Q.) developed in the hybridization
of Tritieum and Agropyron species is applicable to other grasses.
The necessary operations are described as follows: In preparing a plant
for hybridization, several upper and lower spikelets of the inflores-
cence are excised with a small scissors before blooming. Likewise all
but the two lower florets of the remaining spikelets are removed.
Emasculation of these flowers is then effected with slender tweezers
and the inflorescence enclosed in a glassine bag. Several days later,
Figure 25. — A binocular microscope with horizontal arm
adjustment as used in the emasculation of woolly finger-
grass for cross-pollination in the greenhouse.
1072 YEARBOOK, 1937
when the stigmas reach the stage of receptivity, the glassine bag is
removed and pollinations are made, after which the bag is again
replaced to remain until maturity.
In the transfer of pollen the most successful results have been
accomplished by holding a sheet of clean paper beneath the blooming
flowers and slightly shaking them to cause the anthers to expel their
pollen. This pollen is then placed in a convenient ring receptacle
Figure 26. — A bandy pollen carrier devised by W. J. Sando, United States Department
of Agriculture, consisting of an adjustable ring in which are inserted capsules that may
be readily removed and discarded after the pollination process is completed.
(fig. 26), described in a previous publication (17). From this recep-
tacle it is transferred with a pair of tweezers or otherwise to the stigmas
of the flowers previously emasculated. The period of pollen produc-
tion Sando finds can be extended considerably by the following
practice: Holding a culm just below the inflorescence with the left
hand, the head is stroked upward vigorously several times with the
thumb and forefinger of the right hand. This induces the flowers to
extrude their anthers, provided the temperature is favorable. Such
artificial stimulation is most readily accomplished previous |to the
active blooming periods rather than later. High humidity or rainfall
causes the pollen to form a conglomerate mass through the absorption
of moisture from the atmosphere. Such pollen is nonfunctional and
therefore useless in hybridization.
Collecting the Pollen and Pollinating
It will be noted in the previous discussion that Sando applies the
pollen with tweezers while Jenkin prefers to use a soft brush. In
collecting the pollen also Jenkin merely shakes the bagged heads until
all the pollen grains are detached from the anthers and then pours
the pollen out of the bag on a sheet of paper previously creased so
MISCELLANEOUS GRASSES 1073
that it can be folded easily to collect the pollen in the middle of the
sheet.
The time of day when anthesis takes place in various grasses
has been discussed under flowering habits. When two species or
two genera are being crossed, difficulty is sometimes encountered
because the pollen parent does not reach the blooming stage
at the same date as the pistillate parent. Some adjustment of the
blooming period in most grasses may be effected by subjecting one
or both parents to an artificial regulation of the day longth. Sando
(Y. B. Q.) used this method successfully to bring his Agropyron
elongatum plants into bloom at the time his wheat plants were ready
to cross-pollinate.
The length of time pollen grains will remain viable depends alto-
gether on the conditions in which they are kept. When properly
stored they have been known to remain viable several days, but the
safest procedure is to apply the pollen immediately after it is gathered.
More latitude exists in respect to the receptivity of the stigmas.
Stephens and Quinby {29) report for sorghums that "stigmas were
receptive at least 48 hours before the flowers bloomed and from 8 to
16 days after blooming." Jenkin (9) reports for Lolium perenne
that the stigmas were receptive in one case 13 days after emergence,
but none were found receptive on the fifteenth day. It is apparent
therefore that considerable time may elapse before pollen need be
applied to the stigmas.
While Jenkin advises repeated application of pollen, his data show
as good results from two applications as from four or six. It would
seem, therefore, that if the pollen is in good condition and is properly
and thoroughly applied, one replication is sufficient.
Isolation Methods and Materials
When hybridization is being conducted in a greenhouse, ordinary
glassine or waxed paper bags have proved satisfactory for isolating
the inflorescences of parent plants. For field operations, however,
Jenkin (11) found the glassine bags, as used in the greenhouse, useless,
and ordinary parchment paper bags equally unreliable. Cloth bags
woven in seamless pillowcase form and held in place by specially
constructed frames proved most satisfactory. Extensive tests
were made of various cotton fabrics, and it was found that many
of these did not fully prevent the passage of pollen grains.
However, Jenkin found a satisfactory standard fabric, the specifica-
tions of which are: Threads per inch — warp 68, weft 65; count — warp
2/32's, weft 16's.
Cages are also used in the field to prevent unintended pollination,
and special ventilated rigid boxes which may be adjusted over a single
culm have been constructed and used by some breeders. The latter,
however, are too expensive for extensive use. All experienced breeders
agree that unless great care is used in bagging, the results of other-
wise careful work may be vitiated by unfavorable conditions within
the bag. Failure of bagged heads to produce seed is in many cases
caused by these unfavorable conditions rather than by incompati-
bility of the parents.
1074 YEARBOOK, 1937
Inheritance of Characters
Only a very limited amount of data is available on this subject.
Those who have studied Triticum-Agropyron hybrids agree that the
perennial nature of the Agropyron parent is dominant in the Fi hybrid.
The proportion of perennials quite naturally decreases rapidly in suc-
ceeding generations of backcrosses on the annual Triticum species.
According to Verushkine (35), only 43 to 66 percent of the second
generation plants are perennials. He remarks that the F2 affords a
wide segregation of characters and includes for the most part inter-
mediate types.
Armstrong (1), of the Central Experimental Farm, Ottawa, Canada,
agrees with Verushkine in general as to the dominance of the perennial
character in the Triticum-Agropyron hybrids. He names several other
Agropyron characters that are dominant, but finds a condition of
intermediacy in respect to quantitative characters such as spike
density, glume width, and leaf width and scabrousness. When
awned wheats were used as the pistillate parent and A. glaueum
as the pollen parent, the hybrids were awn-tipped, an intermediate
condition. When A. elongatum was used as the pollen parent the
hybrids were awnless in most cases. Both species of Agropyron are
awnless.
The presence in Lolium multiflomm of a root substance that causes a
fluorescence on filter paper when examined under ultraviolet light has
been used to distinguish this species from L. perenne. Woodforde
(89), of the Tasmanian Department of Agriculture, reports that this
character is inherited as a simple Mendelian dominant dependent on a
single factor. However, he found no genetic linkage between fluores-
cence and awned flowering glumes, a distinguishing character of L.
multiflorum.
Jenkin (12), of the Welsh Plant Breeding Station, in a study of
bulbous tall oatgrass, found in the Ft of a cross of the nonbulbous and
bulbous forms an intermediate condition in respect to bulb develop-
ment, although all Fi plants were definitely bulbous. In the F2 and
F3 there was an apparent segregation for bulb development, which was
hard to analyze, since a great majority of the plants were more or less
bulbous. He concludes that more than one pair of factors is concerned
in bulb development, and that the same is true of the hairiness of stem
nodes, another distinguishing character of bulbous tall oatgrass. The
value of this research lies in the fact that the bulbous form behaves as
a weed in cereal fields under certain conditions, while the nonbulbous
form does not. LITERATURE CITED
(1) Armstrong, J. M.
1936. IIYB1UDIZATION OF TRITICUM AND AGROPYRON. I. CROSSING RE-
SULTS AND DESCRIPTION OP THE FIRST GENERATION HYBRIDS.
Canad. Jour. Research (C) 14: 190-202, illus.
(2) Avdulov, N. P.
1931. KARYO-SYSTEMATISCHE UNTEHSUCHUNG DER FAMILIE GRAMINEEN.
428 pp., illus. Leningrad. (Trudy Prikl. Bot., Genet, i Selek.
(Bull. Appl. Bot., Genet., and Plant Breeding Sup.) 44).
(3) Beddows, A. R.
1931. SEED SETTING AND FLOWERING IN VARIOUS GRASSES. Welsh Plant
Breeding Sta. [Bull.] (H) 12: 5-99.
MISCELLANEOUS GRASSES 1075
(4) DE VlLLIERS, S. R.
1934. THE TREND OF PASTURE RESEARCH, WITH SPECIAL REFERENCE TO
breeding. Farming in South Africa. 9: 380-388, illus.
(5) Fruwirth, C.
1916. BEITRAGE ZU DEN GUCNDLAGEN DER ZUCHTUNG EINIGER LAND-
wirtschaftlicher kulturpflanzen. v. graser. Naturwis-
Hcntschaft Ztschr. Forst u. Landw. 14: 127-149.
(6) Gaiser, L. O.
1926-30. chromosome numbers ik angiosperms. I-II. Genctica 8:
[401]-484, 1926; Bibliog. Genetica 0: 171-466, 1930.
(7) Gregor, J. W.
1928. pollination and seed production in THE RYE-GRASSES (LOLIUM
perenne and lolium italicum). Ilov. Soc. Edinb. Trans. 55:
773-794.
(8) Hopkins, C. G.
1910. soil fertility and permanent agriculture. 653 pp., illus.
Boston, New York [etc.].
(9) Jenkin, T. J.
1924. the artificial hybridisation of grasses. Welsh Plant Breeding
Sta. Pull.] (H) 2: 1-18.
(10)
1931. SELF-FERTILITY IN PERENNIAL RYE-GRASS (LOLIUM PERENNE L.).
Welsh Plant Breeding Sta. Bull. (H) 12: 100-119.
(11)
1931. the method and technique of Selection, breeding, and strain-
building in grasses. Imp. Bur. Plant Genetics, Herbage
Plants Bull. 3: 5-34.
(12) ■
1931. SWOLLEN STEM INTERNODES AND OTHER CHARACTERS IN ARRHENA-
tiierum beauv. Welsh Plant Breeding Sta. Bull. (H) 12:
120-147, illus.
(13)
(14)
1933. INTERSPECIFIC AND INTEIIGENERIO HYBRIDS IN HERBAGE GRASSES.
I. initial crosses. Jour. Genetics 28: 205-264.
1935. INTERSPECIFIC AND INTERGENERIC HYBRIDS IN HERBAGE GRASSES.
II, l. perenne x l. temulentum. Jour. Genetics 31: 379-411.
(15) and Sethi, B. L.
1932. PHALARIS ARUNDINACEA, PH. TUBEROSA, THEIR Fj HYBRIDS AND
hybrid derivatives. Jour. Genetics 26: 1-36, illus.
(16) Karper, R. E., and Chisholm, A. T.
1936. chromosome numbers in sorghum. Amer. Jour. Bot. 23: 369-
374, illus.
(17) Leighty, C. E., and Sando, W. J.
1925. A handy pollen carrier. Jour. Heredity 16: 63-65, illus.
(18) Levy, E. B.
1936. ryegrass strains. Seed and Nurserv Trader [Melbourne], 34 (6) :
1-4.
(19) Malte, M. O.
1921. breeding methods in forage plants. Sci. Agr. 1: 25-29, illus.
(20) MiiNTziNG, A.
1935. berattelse over verksamheten vid sveriges UTSADESFOREN-
INGS KROMOSOMAVDELNING UNDER TIDEN 1 OKTOBER 1931-30 SEP-
TEMBER 1935. Sveriges Utsiidesfor. Tidskr. 45: 305-320, illus.
(21) Nilsson, F.
1934. STUDIES IN FERTILITY AND INBREEDING IN SOME HERBAGE GRASSES.
Hereditas 19: 1-162.
(22)
1935. AMPHIPOLYPLO'IDY IN THE HYBRID FESTUCA ARUNDINACEA X FESTUCA
oigantea. Hereditas 20: 181-198, illus.
(23) Ontario Department of Agriculture.
1934. breeding improved strains of grasses, clovers, and alfalfa.
Ont. Dept. Agr., Ontario Agr. Col. and Expt. Farm Ann. Rept.
60: 102.
1076 YEARBOOK, 1937
(24) Pkto, F. H.
1930. CYTOLOGICAL STUDIES IN THE GENUS AGROPYRON. Caiiad. Jour.
Research 3: 428-448, illus.
(25) Piper, C. V., Vinall, H. N., Oakley, R. A., Carrier, L., Baker, O. E.,
Cotton, J. S., and others.
1924. our forage resources. U. S. Dept. Agr. Yearbook 1923: 311—
414, illus.
(26) Rancken, C.
1934. ZYTOLOG1SCHE UNTEliSUCHUNGEN AN EINIGEN W1RTSCHAFTLICH
WERTVOLLEN WIESENGRASERN, MIT BESONDERER BERUCKSICHTI-
GUNG VON STRUKTURELLEN ABWEICIIUNGEN IN DEM CHROMO-
somenkomplement. Suomen Maataloustieteellisen Seuran Jul-
kaisuja (Acta Agralia Fennica) no. 29, 96 pp., illus.
(27) Stapledon, R. G.
1931. SELF- AND CROSS-FERTILITY AND VIGOUR IN COCKSFOOT GRASS
(dactylis glomerata l.). Welsh Plant Breeding Sta. Bull.
(H) 12: 161-180.
(28) Stephens, J. C., and Quinby, J. R.
1933. bulk emasculation of sorghum flowers. (Note) Jour. Amer.
Soc. Agron. 25: 233-234, illus.
(29) and Quinby, J. R.
1934. anthesis, pollination, and fertilization in sorghum. Jour.
Agr. Research 49: 123-136, illus.
(30) Tischler, G. «
1927-36. pflanzliche chromosomenzahlen. In Junk, W., ed., Tabulae
Biologicae, v. 4 pp. 1-83, 1927; v. 7, pp. 109-226, 1931 ; and
Tabulae Biologicae Periodicae, v. 6, pp. 57-155, 1936.
(31) United States Department of Agriculture, Forest Service.
1933. a national plan for American forestry ... 73d Cong., 1st sess.,
S. Doc. 12, 2 v., illus.
(32) United States Department of Commerce, Bureau of the Census.
1936. united states census of agriculture; 1935. reports for states,
with statistics for counties and a summary for the united
states. Ser. 2, 2 v.
(33) [United States] National Resources Board.
1934. REPORT OF THE LAND PLANNING COMMITTEE. In Report, pt. 2,
pp. 89-251, illus. Washington, D. C.
(34) Vakar, B. A.
1934. MATERIAL FOR THE STUDY OF WHEAT HYBRIDS. CYTOLOGICAL
contributions. 106 pp., illus. Omsk. (Siberian Inst. Sci.
Research of Grain Management, Cytol. Lab. Rept.) [In
Russian.]
(35) Verushkin, S. M.
1935. on the hybridization of triticum by agropyron. 37 pp., illus.
Saratov. [In Russian. English summary.]
(36) Wenholz, H.
1934. PLANT breeding in new south wales, seventh year op prog-
ress, 1932-33. N. S. Wales Dept. Agr. Sci. Bull. 45, 58 pp.
(37) Wiley, H. W.
1906. principles and practices of agricultural analysis; a manual
for the study of soils, fertilizers, and agricultural
products; for the use of analysts, teachers, and students
OF AGRICULTURAL CHEMISTRY. V. 1, illllS. Easton, Pa.
(38) Wolfe, T. K.
1925. OBSERVATIONS ON THE BLOOMING OF ORCHARD GRASS FLOWERS.
Jour. Amer. Soc. Agron. 17: 605-618.
(39) Woodforde, A. H.
1935. THE INHERITANCE OF A SUBSTANCE IN THE ROOTS OF SEEDLING
HYBRID DERIVATIVES OF LOLIUM PERENNE L. X LOLIUM MULTI-
FLORUM LAM. CAUSING A FLUORESCENCE REACTION VISIBLE IN
FILTER-PAPER BY SCREENED ULTRA-VIOLET LIGHT. Jour. Linn.
Soc. London, Bot. 50: 141-150.
MISCELLANEOUS GRASSES
APPENDIX
Table j. — Development renters of important grasses useful in breeding 1
1077
Region
Grasses 3
Common name Scientific name
(1) Europe, except the Medi-
terranean region and the
eastern or dry portion of
the Union of Socialist
Soviet Republics.
(2) Mediterranean region of
Europe and Africa.
(3) Eastern Union of Socialist
Soviet Republics and Si-
beria.
(4) Southern Union of Soviet
Socialist Republics, Tur-
kistan, Sinkiang (China),
Turkey, Palestine, and
Afghanistan.
(">) Tibet, western provinces
of China, and eastern Mon-
golia.
(0) Eastern Siberia, Man-
churia, northeastern China,
Chosen, and Japan.
Redtop .
Bentgrass
Bcachgrass
Tall oatgrass
Awnlcss bromcgrass.
Cocksfoot or orchard grass.
Reed or tall fescue
Meadowfescue . .
Italian ryegrass.. . .
Perennial ryegrass. ...
Mountain timothy. . .
Timothy .
Mountain bluegrass
Annual bluegrass
Canada bluegrass .
Kentucky bluegrass
Rough-stalked bluegrass .
Cordgrass
Giant reed
Wild oats (annuals)
Bromes (annuals: cheat or chess) _.
Red fescue
Canary grass. .
Harding grass .
Esparto grass..
Whoatgrasses.,
Agroslis alba.
Agrostissyiyi.
Ammophila areanaria.
Arrhenathernm elalius.
Bromusinermis.
Dactylis ascltersoniana.
J), g/omerata.
Fesluca elalior var. arundinacea.
F. e/ntior var. pratensitt.
Lallum muttlftorum.
L.perenne.
Phleum alpinvtn.
P. boehmeti.
P. pratetise.
Poa aipina.
P. annua.
P. compressa.
P. pratensis.
P. tririatis.
Spartina townsendii.
Arundo donar.
Avcna barbata, A.fatua, A. steri/is, A.
strigosa.
Uromusarvensis, IS. mollis, 11. seealinus,
B. steritis.
Fesluoa rubra .
Plialaris canadensis.
P. tuberosa.
SHpa tenacissima.
Agropyron caninum, A. cristatum, A.
ehongatum, A. intermedium, A. tri-
ekophorum.
Calamagroslis spp.
Klymus spp.
Pest nca oirina.
Oryzopsis spp.
Slipa splendens.
Aegilops crassa, A. eglhidrica, A. opata,
A. squarrosa, A. triuncialis.
Alopecurus pratensis.
Anthoxanthum odaratum.
Arena barbata, A. falna, A. slerilis,
A. strigosa.
Festuca rubra.
Jtordeum species.
Poa bulbosa.
Secate cereale.
Sorghum halepense.
Triticum spp.
Agropyron spp.
Mymus spp.
Festuca spp.
Poa aipina, P. attenuate, P. nemoralis,
P. tibelica.
Slipa spp
Arundinella spp,
Calamagroslis epigeios.
Kckinochloa colona.
K. crus-gaUi.
Panicum millaceum.
Maria italica.
Setaria spp.
y,oysiajaponica.
Z. matrella.
Sorghum rntgare.
' Numbers otrogions correspond to those in fig. 1.
2 tn naming the grasses characteristic of a region no attempt has been made to restrict them to native
species, since in certain areas the introduced species are more abundant and more important than the native
ones. Some grasses, omitted because of their apparent lack of usefulness, are more widely distributed and
more characteristic of a region than are any of the species named. It should be understood also that in most
cases other species of tho genera listed occur in the region.
Rmlgrasses.
Wild-rye — .
Sheep fescue
Ryegrasses..
Cheegrass..
Goatgrasses.
Meadow foxtail
Sweet vernal grass ..
Wild oats
Red fescue
Barley relatives . _ .
Bulbous bluegrass.
Rye
Johnson grass
Wheat relatives . _
Wheatgrasses
Wild-ryes
Fescues
Bluegrasses _.
Needlegrasses.
Manchu reedgrass...
Jungle riee
Japanese millet..
Broomcorn millet. _
Foxtail millet
Bristlegrasses
Japanese Iawngrass .
Manila Iawngrass. .
Sorghums.
1078 YEARBOOK, 1937
Table 1. — Development centers of important grasses useful in breeding — Continued
Region
Grasses
Common name
Scientific name
(7) India, southeastern
China, Burma, Malay
Peninsula, Sumatra, Java,
Borneo, New Guinea, Tai-
wan.
(8) Australia, New Zealand,
and Tasmania.
(9) Equatorial Africa..
(10) Africa south of 10°
south latitude, which in-
cludes southern Angola
and Tanganyika, all of
Nyassaland, Mozambique,
Rhodesia, Beehuanaland,
South Africa, and Mada-
gascar.
(11) Brazil, eastern Bolivia,
Paraguay, Uruguay, and
northeastern Argentina.
(12) Andean region of Peru,
Bolivia, Chile, and Argen-
tina.
(13) Southern Mexico, Cen-
tral America, northwestern
South America, and the
West Indies.
Angleton grass
Dwarf bamboo
Bamhoo _
"Doob" (Bermuda) grass
Finger millets
Contipede grass
Ccgon grass
Kicegrass
Kutki millet
Koda millet..-
Edible bamboo
Sugarcane relatives
Sorghums —
Native grasses (grown in dry
areas) :
Mitchell grass
Curly Mitchell grass
Wallaby grass _
Flinders grass
Australian tussock grass
New Zealand tussock grass
Silvery sandgrass
Kangaroo grass
Spinifox
Introduced grasses (grown where
rainfall is adequate) :
Rhodes grass
Orchard grass
Meadow fescue
Italian ryegrass
Perennial ryegrass..
Daiiis grass
Blucstem relatives
Brachiarias...
Tefl
Carib grass.
Wild barleys
Guinea grass
Para grass
Bentham grass
Kikuyu grass
Pearl or cattail millet
Merker grass
Napier or elephant grass
Sorghums
Grass sorghums... ___
"Rooi gras" or red grass
II erringbono grass
Rhodes grass __.
"Kweek" (Bermuda) grass
Red kweek grass
Woolly finger grass
Other fmgergrasscs
Sorghums _
Grass sorghums _
"Rooi gras" or red grass
Natal grass
Carpet grass
Pampas grass
Jaragua grass...
Molasses grass
Rice
Guinea grass... _ __
Bahia grass
"Maicillo" or "cachi"...
Reedgrasses.
Fescues
Muhly grass
Bluegrasses
Giant reed _
Carpet grass
"Malojilla" or Caribgrass
Teosinte _
Andropogon annvlatus.
Bambusa nana.
B. vulgaris.
Cynodon dadylrrn.
Eleusine coracana.
Kremochloa ophiuroides.
Imperata cylindrica.
Oryza sativa.
Panicum psilopodium.
Paspalum scrobiculatum.
Phylloslachys edulis.
Saccharum spp.
Sorghum vulgare.
AstreUa pectinala.
A. triticoides.
Danthonia semiannularis.
Iscilema membranacea.
Poa caespitosa.
P. ftabellata.
Spinifex hlrsuta.
Themeda spp.
Triodia spp.
CiUoris gayana.
Dadylls glomerata.
Fesluca pratensitt.
LoUum muUifiorum.
L. perenne.
Paspalum dilatatum.
Andropogon spp.
Brachiaria spp.
Eragrostis abyssinlca.
Briochtoa polystachya.
liordeum spp.
Hyparrhmia spp.
Panicum maximum.
P. purpurascens.
Pennisetum benlhami.
P. clandestinum.
P. glaucum.
P. merkeri.
P. purpureum.
Sorghum vulgare.
S. vulgare vars.
Themeda Mandra.
Urochloa pullulans.
Chloris gayana.
Cynodon dactylon.
C. hirsutus.
Digitaria eriantha slolonifera.
Dig'taria spp.
Khrharia calycina.
llyparrhenia spp.
Sorghum vulgare.
S. vulgare vars.
Themeda Mandra.
Tricholena rosea.
Axonopus cornpressus.
Cortaderia selloana.
llyparrhenia rufa.
Melinis minutijlora.
Oryza sativa.
Panicum maximum.
Paspalum notalum.
Axonopus scoparius.
Calamagroslis spp.
Fesluca spp.
Muhlenbergia spp.
Poa spp.
Arundo donax.
Axonopus cornpressus.
Eriochloa polystachya.
FJuchlaena mexicana.
MISCELLANEOUS GRASSES 1079
Table 1. — Development centers of important grasses useful in breeding — Continued
Grasses
Region
(14) Great Plains and inter-
mountain regions of North
America.
(15) Southeastern Canada
and northeastern United
States.
Common name
Mexican toosinte
WiUlrico— -.-
Guinea grass
Para grass
Bahia grass
St. Augustine grass
Kaslern ganiagrass ... ..
Long-leaved ganiagrass
Guatemala grass
Corn (maize)..
Native grasses:
Thickspike wheatgrass
Slender wheatgrass
8 treamba nk wheatgrass
Bluestem (western wheat
grass).
Bluebunch wheatgrass
Iieardod wheatgrass
Big bluestem.. __;
Turkeyfoot
Sil ver beardgrass
Little bluestem
Six-weeks grama
Crowfoot grama
Side-oats grama
Black grama
Hairy grama
Rothrock grama
California bromegrass
Buffalo grass
Pine grass
Long-leaved sandgrass
Canada wild-rye
Giant wild-rye
Beardless wild-rye
Virginia wild-rye
Bluebuuch fescue
Six-weeks fescue
Sheep fescue
Red fescue
Greeuleaf fescue
Curly mesquite
Galleta grass
Junegrass
Switchgrass
Canby bluegrass
Nevada bluegrass
Sandberg bluegrass
Nuttall alkali-grass
Blowout grass
Indian grass
Alkali saca ton .
Sand dropseed
Saca ton
Long-awned spear grass
Introduced grasses:
Crested wheatgrass
Awaless bromegrass
Bulbous bluegrass...
Sudan grass
Native grasses:
(Juackgrass.
American beachgrass.
Big bluestem.
Little bluestem
Bluejoint
Virginia wild-rye.
American mannagrass
Switchgrass.. _
Reed canary grass
Smooth cordgrass
Big cordgrass
Saltmeadow cordgrass.
Prairie cordgrass
Eastern ganiagrass
Wild rice.
Scientific name
E. perennh:
Oryzalatifotm.
Panicum maximum.
P. purpurascens.
Paspalum notatum.
Shmotuphru m secundaturn.
Tripsucum dactyloides.
T. latifolium.
T. laxum.
Zea mays.
Ayropyron dasystacliyum.
A. pauciflorum.
A. riparium.
A. smitliii.
A. spicatum.
A. subsecundum.
Andropogon furcatv-s.
A. hullii.
A . saccliaroides.
A. scoparius.
Boutetoua barbata.
B. chrondrasioides.
B.curtipendula.
B. eriopoda.
B. hirsuta.
B. rolhrockii.
Bromus carinalus.
Buehloe dactyloides.
Calamayroslis rubescens.
Calamovitfa lonyifolia.
Elymus canadensis.
E. condensatus. •
E. triticoides.
K. rtrginiaii.
b'estuea idaltoensis.
P. octo/lora.
P. ooina.
P. rubra.
P. riridula.
Ililaria be/anger I.
li.jamesii.
Koekria cristata.
Panicum virgatnm.
Poa canbyii <P. laevigata).
P. nenadensis.
P. secunda (P. sandbergii).
Puccinellia nuttaltiana.
Redfiatdia ftccuosa.
Sorgkastrum nutans.
Sporobotus airoides.
H. cryptandrus.
S. wrightii.
SHpa cornata.
Ayropyron crista! urn.
Bromus inermis.
Poa bulbosa.
Sorghum milgare var. sudanense.
Ayropyron repens.
A mmophila brerUigutala.
Andropogon f ureal us.
A. scoparius.
Catumagrostis canadensis.
Elymus viryinicus.
iUyceria grandis.
Panicum tiryatum.
Phalaris arundinacea.
Spartina alterni flora.
S. cynosuroides.
S. patens.
8. pedmata.
Tnpsacum daetyloides.
Zizania aquatica.
1080 YEARBOOK, 1937
Table i. — Development centers of important grasses useful in breeding — Continued
Grasses
Region
Common name
Scientific name
Introduced grasses (see also list for
region]):
(16) Southeastern United
Native grasses:
Introduced grasses:
Bromus caiharticus.
Centipede grass -_
Para grass
Eremochloa ophiuroides.
Panicum purpurascens.
Paspalum dilatatum.
Pearl millet ._
Japanese cane __ __ . _
Pennisetum glaucum.
P. purpureum.
Saccharum ckinense.
Table 2. — Objectives and progress in the selective breeding of grasses as reported by workers in the United States and Canada
£ Location 1
X
CD
Individual workers
Genera and species
Period work under
way
Objectives
Success attained
4^
° UNITED STATES
M Arizona:
i Tucson*
Bouleloua curtipendula, B.
eriopoda, B. gracilis, Hi-
laria bclangeri, II. jamesii,
II. mutka, H. rigida, Mvh-
lenbergia porteri, Ory-
zopsis coerulescens, 0. hy-
menoides, 0. ■riiiliaceu, Set-
aria macrostachya.
Sorghum vulgare var. sudan-
eme.
1936 (continued) _ _
Increased seed and forage production, lon-
gevity, and drought resistance.
Increased hay and pasture production
Increased seed and forage production, lon-
gevity, and drought resistance.
i
!
OS
O
+
+
California:
L. G. Goar
E. W. Hardies
Alvin Kezer
D. "W. Robertson and Otto
Coleman.
G. E. Eitchey and W. E.
Stokes.
G. E. Ritcbey and F. H.
Hull.
G. E. Ritchey and V". E.
Stokes.
.T. L. Stephens and O. W*.
Burton.
Much.
Colorado:
Colorado Springs*
Fort Collins
1936 (continued)-.
lg'O-H
variants found.
Florida:
Sorghum vulgare var. sudan-
ense.
Axonopus compressus .
Axonopus furcatus
1934 (continued) ..
(a) Yield and uniformity of seed; (b) reduced
hydrochloric acid content.
(a) Increased pasturage value: (b) reduced
stolon development.
(a) Much.
(a) Much; (b)
do..
little.
Much.
1933 (continued) ..
1931 (continued)-.
1933 (continued) _ _
do
Increased seed production and pasturage value-
Increased seed production, pasturage, and
lawn value,
(a) Increased pasturage value, (b) early seed
production; (c) winter hardiness.
Increased pasturage value and disease resist-
tance.
Increased pasturage and silage value and resist-
ance to leaf spot.
Increased hay and pasture production and
winter hardiness.
Increased seed production, palatability, and
winter hardiness.
Increased viablo soed production, better turf,
and winter hardiness.
Production of nonshattering seed heads --
Eremochloa ophiuroides..
Much.
(c) little.
Georgia:
Tifton* (Coastal Plain
Experiment Station).
Pennisetumpurpureum. ___
Cynodon daclylon
1934 (continued) . _
1929 (continued).
1936 (continued) . _
Do.
Medium.
Panicum anlidotale ___
03
en
1 Except where otherwise noted, the work is conducted at the State Agricultural Experiment Station. An asterisk (*) indicates cooperation between the U. S. Department of
Agriculture and the State agricultural experiment station.
o
CO
Table 2. — Objectives and progress in the selective breeding of grasses as reported by workers in the United States and Canada — Continued
©
03
tO
Location
united states — continued
Georgia — Continued.
Tifton* (Coastal Plain
Experiment Station).
Iowa:
Ames.
Illinois:
Trbana.
Kansas:
Hays* (Fort Hays
Branch of Kansas
Agricultural E x p er i -
ment Station) .
Manhattan*
Kentucky:
Lexington.
Individual workers
J.L. Stephens and G. W.
Burton.
H. D. Hughes and F. S.
Wilkins.
O. T. Bonnett_
D. A. Savage, H. E. Run-
yon, and R. E. Solomon.
A. E. Aldous..
E. N. Fergus-
Genera and species
Panicum purpurascens .
Paspalum dilatatum
Paspalum notatum
Pennisetum p'urpureum.
Sorghvm nilgare var. sudan-
ense..
Phnlaris arundinacea--. . ..
Agrosiisalba..
Poa pratensis-.
Period work under
Agropyron pungens, A . semi-
costalum, A. smilhii.
Andropogon furcatus, A.
hallii, A. scoparius, BotUe-
loua gracilis, B hirsuta.
Buchlol daclyloides
Bromus inermis
Klymus virginicus. _ .
Sorghaslrum nutans.
Andropogon furcatus, A.
scoparius.
Browns inermis
Arrhenatherum elatius.
Dadylis glomerata
Festuca etatior
Poa prattnsis
1031 (continued)..
....do
.do. .
...do.
-do.
.do.
.do.,
.do..
1928 (continued)..
1930 (continued).
1931 (continued)..
10 years
1931 (continued)..
7 years
Objectives
Winter hardiness and earliness
Increased production of viable seed, leanness,
and disease resistance.
do
Increased forage value and resistance to hel-
minthosporium eye spot.
Resistance to foliage diseases..
Increased seed and forage, disease resistance,
leafiness, and density of turf.
Increased yield of forage, disease resistance,
and winter hardiness.
Increased yield of forage, resistance to leaf rust
and mildew, and winter hardiness.
In general the objective for all grasses is to
develop drought-resistant grasses suitable
for reseeding and resodding on different soil
types in the central and southern Great
Plains and to improve their forage value.
Special attention given to increased seed pro-
duction and viability.
Special attention given to increased seed pro-
duction and viability, and rapidity of vege-
tative spread.
Especially to develop a type that will endure
high temperatures.
Especially to improve forage quality
Special attention given to increased seed pro-
duction and viability.
Increased seed and forage values and drought
resistance.
do
Success attained
Much.
Many promising
variants found.
Comparing local strain with commercial
Increased forage production __,
Comparing local strain with commercial '
Increased forage production, disease resistance, j
and tur ldensity. '
So
to
o
Maryland:
Beltsville (National Ag-
ricultural Research
Center).
College Park
Michigan:
Augusta* (W. K. Kel-
logg Demonstration
Farm).
Mississippi:
State College
Missouri:
Columbia'"
Montana:
Bozeman* -
Havre* (Northern Mon-
tana Branch Station).
Moccasin* (Judith Basin
Branch Station).
Nebraska:
Lincoln*
Now Jersey:
New Brunswick -
New York:
Ithaca-.
H. N. Vinall and
Hein.
M. A.
J. E. Metzger and
Eppley.
G. F.
H. W. Bennett —
E. M. Brown
L. P. Reitz—
M. A. Bell — _'
X. F. Woodward,
Tower, and J. E.
n. E.
Norton.
L. 0. Newell, A. I,
and F. D. Keim.
Frolik,
D. B. Johnstone- Wallace
and C. H. Myers.
Dadylis glornerata...
Zolium mulliflorum.
Loliutn perenne
Poa compressa
Poa pratensis
Fesluca rubra
Cynodon dactylon-.
Poa pratensis -
Cynodon, Digiiarin, Lolium,
and Paspalum spp.
Dadylis glomerala
Poa pratensis
Fesluca rubra _ _-_
Lolium perenne
Sorghum vulgare var. sudan-
ense.
Various native grasses
Agropyron cristatum
Agropyron inerme. _
Agropyron smithii
Agropyron cristatum
Agropyron cristatum, A,
smithii, Andropogon fur-
catus, A. scoparius, Boute-
loua gracilis, JB. cvrtipen-
dula, Bromtis inermis,
Buchloe daclyloides, Dac-
tylis glomerala, Panicum
virgatum, Phalaris arundi-
nacea, Sorghastrum nutans.
Agroslis canina..
Fesluca rubra
Pactylis gtomerata.
1932 (continued)—
1930 (continued).-.
do
1934 (continued)—
—_do
5 years -
1930-36-.
1931-36..
1936 (continued).
1 93fl (continued) _
1932 (continued)..
1930-35.
1930-35.
1930-35-
1936 (continued)—
1925
1934—
1934-
1924-26, 1929-34,
1935 (continued)
1936 (continued) . .
1929 (continued)—
1931 (continued)—
....do—
Pasture and hay types, leanness, and late Medium
maturing.
Late maturing and rust resistance
Rust resistance and summer forage production-
Leanness and increased density of turf
Summer forage production
Increased seed production and fine turt value-
Winter hardiness —
Summer forage production and leafmess _
Increased seed production and forage value-
Increased pasturage production and leafiness..
Increased pasturage production, drought, and
heat resistance; dense turf.
Increased seed and forage production
do—-.
....do — -
.do..
_do_.
-do-
-do..
-do..
Incrcased seed and forage production, drought
and disease resistance, palatability, and
longevity.
Increased seed, resistance to Pythium and
brown patch, and turf quality.
Increased seed, resistance to Pythium and
creeping habit.
Improved pasture types..
Do.
Little.
Medium
Do.
Do.
Do.
Do.
Medium.
Do.
Do.
Much.
Medium.
Much.
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Tablb 2.-0bjectives and progress in the selective breeding of grasses as reported by tvorhers in the United States and CaimJa-Continued
Iiocation
Individual workers
TNTTED STATES— Continued
North Dakota:
Dickinson* (substation) „
Mandan* (United States
Northern Great Plains
Field Station).8
Oklahoma:
Woodward* (United
States Southern Great
Plains Field Sta(ion) .
Leroy Moomaw...
George A. Rogler.
D. A. Savage, H. E. Run-
yon, and R. E. Solomon.
Stillwater.
W. B. Gernert.
Genera and species
Period work under
way
Objectives
AgTopyron cristatum.
...do.
Agropyron smithii
Andropogon furcatus, A.
hallii, A. scoparius.
Bouteloua curtipendnla
Bouteloua gracilis
Bromus inermis ...
Bromus marginatus .
Buchloe dactytoides
FAymus canadensis
Elymus junceus
Oryzopsis hymenoides
Pankum virgatum
Phataris arundinacea
1928-35
1930 (continued).
Agropyron ripens var. pun-
gens, A. smithii, Andro-
pogon furcatus, A. haUii,
A. saccharides, A. sco-
parius, Bouteloua chondro-
xioides, B. curtipendula ,
B. eriopoda, B. hhsuta,
Buchloe dactytoides, Cala-
movilfa longifolia, Elymus
virginicus, Pankum vir-
gatum, Redfieldia fiezuosa,
Sorghastrum nutans, Zoy-
$iajaponica.t
Bromus inermis
Buchloe dactytoides —
Phataris arundinacea
Sorghum vulgare var. sudan-
ense.
...do.
...do.
...do.
...do.
...do.
...do.
..do.
...do.
.do.
.do.
.do.
-do...
Recent years..
....do....
do
do
Increased seed and forage production —
In general the objectives for all grasses at
Mandan are increased seed and forage pro-
duction, viability of seed, forage payabil-
ity, drought and disease resistance, and
seedling vigor.
Rapid spreading of rhizomes, and early foliage
emergence.
Early foliage emergence-
Early foliage emergence and cold resistance
Early foliage emergence
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Cold resistance -- --■
Early foiiage, dense turf, tall seed stalks, rapid
spreading.
Nonshattering of seed.
Early foliage emergence .
Nonshaltering of seed . . .
To develop drought-resistant grasses suitable
for reseeding and resodding on different soil
types in the central and southern Great
Plains and to improve their forage value.
Increased forage production,
do
.do..
.do..
Success attained
Medium.
Much.
ft
las
to
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Oregon:
Corvallis*.
Pennsylvania:
State College.
Rhode Island:
Kingston-.
Texas:
San Antonio 2..
H. A. Schoth and H.
Eampton.
H.
n. B. Musser.
T. E. Odlaud and H. F. A.
North.
Gerald 0. Mott-
B. E. Dickson.
Agrostis oregonensis--
Agrostis paluslris
Agrostis sp
A lopecurus pratensis-
Arrkenatherum etatius
Brachypodium pinnatum-
Bromus inermis
Dactylis glomerata.
Festuca elatior var. arundi-
wicea.
LolivM multiflorum.
Lollum percnne
Phalaris arundinacea.
Phalaris tuberosa var.
optera.
Agrostis canina.-.
Agrostis palustris-
Poaproiensis
Agrostis atba
Agrostis amino...
Agrostis patustris.
Agrostis tenuis
Andropogon furcatus, A.
haltii, A. saccharoides, A.
scoparius, Boutetoua cut-
tipenduia, B. gracilis^ B.
hirsuta, Panicum virga-
tum, Sorghasirum nutans.
Buchloe dactyloides
1935 (continued) _ .
do
1928 (continued) __
1934 (continued)...
1932 (continued)...
1928 (continued)—
1922 (continued)...
1928 (continued)...
1920 (continued)...
1930 (continued) ...
....do
1920 (continued)...
1930 (continued) —
1929-35 —
1929 35
1932 (continued) —
1930-34
1931-35.
1930-34
1930 (continued)....
1934 (continued)..
Few years..
Improved turf and seed production3
Deeper root system and ability to withstand
brackish overflow.
Improved forage, turf, and seed production
Increased forage, uniform seed maturity, and
less shattering.
Increased foliage and less seed shattering
More tender foliage
Reduced rhizome development and early
growth.
Improved forage and turf-forming pasture
types.
More tender foliage and less seed shattering...
Longevity and rust resistance
Longevity, rust resistance, and more seed first
year.
Wider adaptation as to soil and increased seed
production; especially less shattering.
Longevity, less seed shattering, and winter
hardiness.
Fine turf
do
Improvement in pasture value and fine-turf
quality.
Purifying lines
(a) Purifying lines, (b) resistance to dollar
spot, seed production, fine turf.
Resistance to brown patch, dollar spot, and
snow mold; and fine turf,
(a) Eesistance to brown patch, (b) fine turf,
(c) purifying lines.
Increased production and viability of seed,
forage value, longevity, and drought resist-
Seleclion and increased yields of forage and
seed.
Medium.
Do.
Do.
Much.
Do.
Liflle.
Medium.
Do.
Do.
Do.
Much.
Do.
Medium.
Do.
Much.
Do.
Medium,
(e) Much.
Much.
Spur (Texas Substation
no. 7).
2 Bureau of Plant Industry and Soil Conservation Service cooperating.
' In addition to objectives stated, general consideration is given in all species at Corvallis to increasing the quantity and quality of forage and resistance to insects and diseases
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Table 2.— Objectives and progress in the selective breeding of grasses as reported by workers in the United States and Canada — Continued
Location
united states — continued
Utah:
Logan*
Virginia:
Arlington (Arlington Ex-
periment Farm, U. S.
Department of Agri-
culture).
Blacksburg
Washington: <
Pullman-
Pullman*--
Wisconsin:
Madison*
Individual workers
Wesley Keller and Dean F.
McAlister.
Staff of U. S. dolf Associa-
tion, Green Section.
T. K. Wolfe and N. A. Pet-
tinger.
A. L. Hafenrichter and V.
B. Hawk.
D. C. Smith and Q. W.
Fischer.
O. S. Aamodt, F. W. Tin-
ney, and H. L. Ahlgren.
Genera and species
Agropyron cristatam, A.
pauciflorum, A. smithii,
Bromus inermis, Elymus
canadensis, E. condensatus,
Festuca idahoensis, Ory-
zopsis hymenoides, Poa
bulbosa, P. nevadensis,
Spowbolus airoides, Stipa
comata.
Agrostis canina
Agrostis palustris.
Festuca rubra
Poa pratensis
Poa trivialis
Dactylis glomerata
Agropyron cristatum, A .
pauciflorum.
Agropyron cristatum
Agropyron inerme
Agropyron pauciflorum
Arrhenatherum elatius
Bromus inermis
Bromus marginatus.
Dactylis glomerata . .
Elymus canadensis.
Festuca elatior
Phataris arundinacea.
Bromus inermis
Dactylis glomerata
Period work under
way
1930 (continued) -
1920 (continued). .
.—do.
1931 (continued) .. .
....do..
....do..
1920-36.
1935 (continued) .
1936 (continued) .
.do..
_do_
.do.
.do...
-do...
.-..do
....do
1935 (continued) .
1936 (continued) .
Objectives
All species are selected for increased forage pro-
duction, drought resistance, palatability,
and a greater capacity for survival and repro-
duction under moderately heavy grazing.
Dense turf, uniform texture, and resistance to
diseases, trampling, and close clipping,
do.
Dense turf, uniform texture, and resistance to
diseases, rapid spread, and close clipping.
Dense turf, uniform texture, and resistance to
disease, drought, and close clipping.
Dense turf and resistance to diseases and
trampling.
Increased forage value.
Increased seed and forage production
Sustained seed yields, increased palatability,
and resistance to smut.
Leaflness and improved seeding habits
Resistance to drought and diseases.-
Increased palatability and leanness, improved
seeding habits, and smut resistance.
Drought resistance and improved seed produc-
tion.
Smoothness of foliage and smut resistance
Drought and cold resistance and improved
seed production.
Obtaining awnless and finer-stemmed types...
Increased palatability and better seeding
habits.
Drought resistance, winter hardiness, and seed
production.
Increased forage production, resistance to leaf
spot, and reduced rhizomes.
Increased forage production with longer vege-
tative period and drought resistance.
Success attained
Do.
Do.
Little.
Do.
Medium
Much.
Little.
Medium to much.
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Wyoming:
Cheyenne (Cheyenne
Horticultural Field Sta-
tion, U. S. Department
of Agriculture).
Hawaii:
Honolulu.
CANADA
Alberta:
Edmonton (Univcrsitv
of Alberta).
Ontario:
Guelph (Ontario Agri-
cultural College).
H. M. Benedict.-
C. P. Wilsic.
M. O. Matte and (J. U.
Cutler.
O. McConkey..
Poa pratensis _ do.
Agropyron cristatum
Agropyron pauciflorum^
Agropyron smifhii
Agropyron spicalum
Bouteloua curtipendula. .
Bouteloua gracilis
Bromus inermis
Bromus marginatus
Buchloe dadyloides
Elymus condensatus
Stipa comata
Bromus catharlkus _
Diyitaria milanjiana, D.
pentzii.
Pennisetum pvrpureum
Sorghum vulgare var. sudan-
ense.
Agropyron pauciflorum.
Agropyron cristatum..
Agrostis alba -
Bromus inermis
Daclylis glomerata..
Fesluca elatior
Festuca rubra
Lolium perenne
Phalaris arundinacca.
Poa compressor.
P. pratensis
_do_.
.do.,
.do..
.do.,
.do.,
-do.,
.do..
.do..
.do.,
.do..
_do..
1934 (continued) . .
1935 (continued) _.
1933 (continued)..
1933-34-
Several years..
/ years..
10 years .
4 years..
10 years.
10 years.
6 years..
10 years.
6 years..
10 years..
10 years..
Increased forage production, resistance to mil-
dew, and drought resistance.
(■>)-
Emphasis on longevity..
Reduced rhizome development-
Emphasis on palatability. ..
Reduced awn development-
Increased forage and seed production and resist-
ance to smut.
Incroascd pasturage, development of uniform
pasture type.
Increased forage, leanness, and palatability
Increased forage, leanness, and resistance to
smut.
Improved hay type.
<The objectives listed for Washington are the ones to be
atability, and resistance to drought, heat, and disease.
5 All species at Cheyenne are being selected for increased
tional or special objectives are indicated.
Medium.
(a) Much.
(a) and (b) Me-
dium.
(a) Medium.
Much.
(a) and (b) Much.
Medium.
Medium hardiness.
Medium.
Much.
Medium.
emphasized in each instance. In general the objectives for all species arei ncreased seed and forage yields, greater pal-
early growth, seed production, winter hardiness, palatability, longevity, and drought and disease resistance. Addi-
Increased seod production, forage yield, and
(a) leanness.
Increased seed production, disease resistance,
pasturage, (a) leanness, and (b) winter hard-
iness.
Increased seed production, disease resistance,
pasturage, and (a) leanness.
Pasture and pasture-hay type, winter hardi-
ness, and leanness.
Increased seed production, disease resistance,
forage production, (a) leanness, and (b) win-
ter hardiness.
Increased seed production, disease resistance,
and turf and pasture value.
Increased seed and forage, disease resistance,
and winter hardiness.
Increased seed, disease resistance, pasture
value, leanness.
Same, also winter hardiness
— do
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Table 2. — Objectives and progress in the selective breeding of grasses as reported by icorhers in the United States and Canada— Continued g
03
OS
Location
Individual workers
Genera and species
Period work under
way
Objectives
Success attained
Canada— continued
Ottawa (Central Experi-
mental Farm).
Quebec:
Quebec (Maedonald Col-
lege).
Saskatchewan
Saskatoon (Dominion
Forage Crops Labora-
tory).
!
L. E. Kirk and R. McVicar.
L. S. Klinck, L. A. Wait-
zingcr, O. P. McKostie,
A. MacTageart, and J. N.
Bird.
L. E. Kirk and T. M.
Stevenson.
L. E. Kirk
T. M. Stevenson and W. J.
White.
J. Bracken
L. E. Kirk and T. M.
Stevenson.
Agropyron pauciflorum.
Dactylis glomerata
Fesiuca elatior
Poa pratensis _
Dactylis glomerata
Agropyron cristatum
Agropyron paucijlorum.
do
Brornvs inermis
do
1913-20
1912 (continued).
1918 (continued) .
1919 (continued).
;
Increased forage production, uniformity, fine-
ness and abundance of leaves.
Winter hardiness
(a) Increased forage production, (b) uniform-
ity in type suitable for hay and pasture.
(a) Increased forage production, (b) mildew
resistance, (c) upright habit of growth, and
also spreading habit of growth.
1911-33 Increased hay and aftermath, winter hardi-
ness, and longevity.
1915 (continued) . . Increased hay and pasturage.
1922-29 | Increased hay
1933 (continued). Longevity
?-1921 ! Increased hay and pasture
1923 (continued). -i Increased hay and pasture, reduced rhizome
development, leanness, and fineness of stem.
Much.
Do.
(a) Little, (b) me-
dium.
(a) Unestimated,
(b) much, (c)
much.
Medium.
Much.
Medium.
Medium.
Much.
3
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Table 3. — Nature and characteristics of interspecific hybrids previously reported
Parents of cross and chromosome
numbers (2n)
By whom made
Institution
Date of cross
Characteristics of progeny
Dactylis glomerata 28 X V. aschersoni-
ana 14.
Festuca amndinacea 42 x F. gigantea 42,
Do
Milntzing (20)
Swedish Seed Association, Seed
Control Laboratory, Svalof,
Sweden.
Swedish Seed Association, Seed
Control Laboratory, Undrom,
Sweden.
Welsh Plant Breeding Station,
Aberystwyth, Wales.
1931-35
The Fi chromosome number was 21; the
1934 _ _
male sterile and female partially sterile;
when backcrossed on the t>. glomerata pro-
duced well-developed plants that were self-
fertile, more vigorous than the D. glomerata,
and had ± 35 chromosomes.
Chromosome number of the Fi was 42, but
Jenkins)1 -
1930
Fi progeny plants differed very much, one
having a chromosome number of 84.
Fi sterile, pollen not liberated; but in many
F.prntentfx 14 X F. arundinacea 42__. ._
Do
cases the ¥i plants can be used as female
parents for backcrossing, some more readily
than others.
Cross reported successful, but no description
Jenkin (IS) '.
Welsh Plant Breeding Station,
Aberystwyth, Wales.
-do
1924, 1928
of progeny was given.
Fi sterile, pollen not liberated; but in many
do
..do _
1930_
cases the Fi plants can be used as female
parents for backcrossing, some more readily
than others.
Do.
do
1922,1928,1930,1931....
mo..
10 percent of pollinated flowers produced
.do.. _ .
. __do__
seeds, but none of these germinated.
Fi sterile, pollination very incomplete; but
Lolium perenne 14 X L. multiflorum 14.-
Do
Woodforde (39)
Department of Agriculture, Tas-
mania, Australia.
Welsh Plant Breeding Station,
Aberystwyth, Wales.
do _._
in many cases the Fi plants can be used as
female parents for backcrossing, some more
readily than others.
Tho F2 segregated in a ratio of 3.4:1 for seed-
Various
ling fluorescence, a characteristic of L.
multiflorum. Italian characters were dom-
inant. No genetic linkage between fluo-
rescence and awned glumes.
Fi fertile; provisional conclusion that better
do
do _
results by selecting within either L. perenne
or L. multiflorum than from the hybrid
progeny.
Fi sterile, pollen not liberated; but in many
£. perenne 14 X L- rigidum ._.
do
do
cases the Fi plants can be used as female
parents for backcrossing, some more readily
than others.
Fi fertile, but no description of progeny given.
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1 Reported in correspondence (Y. B. Q.).
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Table 3. — Nature and characteristics of interspecific hybrids previously reported — Continued
Parents of cross and chromosome
numbers (2«)
By whom made
Institution
Date of cross
Characteristics of progeny
L. perenne 14 X L. temulentum 14.
Welsh Plant Breeding Station,
Aberystwyth, Wales.
.do
1922 --
Fi sterile, pollen not liberated; but in many
do
1935...
cases the Fi plants can be used as female
parents for backcrossing, some more readily
than others. Fi of reciprocal cross similar
in all essential characters.
Cross reported successful, but characteristics
X. temutentum 14 X /.. remoium (?) __ .
..do .
__do_-
1935
of Fi unknown.
Do.
1930
Chromosome number of Fi, 28, of which 12
Poa arachnifera ±80 X P . pratensis 56—-
P. pratensis 56 X P. aijoima 32-34
Sorghum vulgar e 20 X & halepense 40
E. Marion Brown 1
U. S. Department of Agriculture
and Missouri Agricultural Ex-
periment Station, Columbia,
Mo.
Swedish Seed Association, Svalof,
Sweden.
Texas Agricultural Experiment
Station, College Station, Tex.
1934-35 --
are bivalent and 2 univalent. The hybrids
are very vigorous and easily distinguishable
from the parent species.
About 10 percent of the Fi hybrids are fertile;
progeny of these are productive, have more
vigorous rhizomes, and show greater resist-
ance to heat and drought than P. pratensis.
Cross reported successful, but no description
Karper and Chisholm (/(?)
of the progeny given.
Chromosome numbers of Fi, 30; an examina-
1933
tion of the pollen mother cells of Fi plant
showed univalents, bivalents, trivalents,
and quadrivalents, but none of higher
association.
Small percentage of success; Fi partially
pense 40.
sterile.
o
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'Reported in correspondence (Y. B. Q.)
Table 4. — Intergenerlc hybrids previously reported
Parents of cross and somatic chromo-
some numbers
Aegilops cglindrica 28 X Agropyron
elongatum 70.
Aegilops longissima 14 X Agropyron
elongatum 70.
Aegilops speltoides 14 X Agropyron
elongatum 70.
Aegilops crassa 42 X Agropyron inter-
medium 42.
Aegilops speltoides 14 X Agropyron in-
termedium 42.
Aegilops triaristata 28 or 42 X Agropyron
intermedium 42.
Aegilops triunciaiis 28 X Agropyron in-
termedium 42.
Aegilops turcomanica 42 X Agropyron
intermedium 42.
Aegilops variabilis 28 X Agropyron inter-
medium 42.
FesiMca arundinacea 42 X Lolium
perenne 14.
.F.pntfettsis 14 X -£■ perenne 14
By whom made
W.J. Sandoi.
F. rubra 42 or 56 X L. perenne 14 _.
Lolium perenne 14 X F. arundinacea 42.
L. perenne 14 X .F. gigantea 2S-.
do ___
L. perenne 14 X F. OPiwa 28
L. perenne 14 X F. pratensis 14_
do
L. perenne 11 X F. rubra 42
.do..
do _.
Verushkin 1-
do
_do_.
.do..
.do.
do
Jenkin (IS) K.
—.do
_do..
.do..
—.do
F. Nilsson1-.
Jenkin (IS) i.
— .do
F. Nilsson i.
Jenkin (13)..
Institution
U. S. Department of Agriculture,
Bureau of Plant Industry,
Washington, D. C.
— .do
.do-
Central Station of Plant Breeding
and Genetics, Saratov, Union of
Soviet Socialist Republics.
do _
.do..
_do_.
_do_
_do„
Welsh Plant Breeding Station,
Aberystwyth, Wales,
.—do _
.do..
_do_.
.do-
Swedish Seed Association, Svalof,
Sweden.
Welsh Plant Breeding Station,
Aberystwyth, Wales.
— .do _
Swedish Seed Association, Svalof,
Sweden.
Welsh Plant Brooding Station,
Aberystwyth, Wales.
Date made or
reported
1935.
1935.
1935.
1935.
1935
1935
1935
1936..
1935
1921,1928-30.
1922, 1928-31..
1921,1922,1928
1921, 1928, 1929, 1931..
1921
1930
1922, 1928-31.
1921, 1924, 1928. .
Remarks
42 flowers pollinated; 3 seeds obtained, all of
which produced plants.
48 flowers pollinated; 18 seeds obtained, none
of which grew.
106 flowers pollinated; 2 seeds obtained, none
of which produced plants.
46 flowers pollinated; 29 seeds obtained, 63
percent pollinations successful.
28 flowers pollinated; 8 seeds obtained, 28.5
percent pollinations successful.
6 flowers pollinated; 3 seeds obtained, 50 per-
cent pollinations successful.
12 flowers pollinated; 2 seeds obtained, 10.6
percent pollinations successful.
18 flowers pollinated; 10 seeds obtained, 55.5
percent pollinations successful.
22 flowers pollinated; 6 seeds obtained, 27.3
percent pollinations successful.
429 flowers pollinated; 26.8 percent set seed,
but none germinated.
1,513 flowers pollinated; 27 percent set seed;
4.9 percent germinated; 7 plants established
Fi male sterile.
181 flowers pollinated; 13 seeds obtained; 7.2
percent set seed, but none germinated.
654 flowers pollinated; 32.9 percent set seeds
39.5 percent germinated; 75 plants estab-
lished, Fi sterile.
Successful in obtaining seed, but Fi sterile.
Cross reported successful, but no description
given.
150 flowers pollinated; 16.7 percent set seed;
none of which germinated.
2,046 flowers pollinated; 41.1 percent set seed,
germination 0.7 percent; .1 plant established ;
Fi sterile.
Cross reported successful, but no description
given.
218 flowers pollinated; 45.4 percent set seed;
germination 18.2 percent; 9 plants estab-
lished; Fi sterile.
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en
tq
i Reported in reply to the Yearbook questionnaire, 1936.
O
Table 4. — Intergeneric hybrids previously reported — Continued
o
to
Parents of cross and somatic chromo-
some numbers
L. perenne 14 X F. rubra 42
Triticvm dkoccoides 2S X Agropyron
elongatum 70.
T. spelta 42 X A. elongatum 70
T. aestivum 42 X A. elongatum 70_
T. dkoccum 28 X A. glaucum 42_.
T. durum 28 X A. glaucum 42
'P. aestivum 42 X A- glaucum 42
T. dkoccum 28 X A. elongatum 70 .
T. durum 28 X A. elongatum 70
T. aestivum 42 X A. elongatum 70_.
7". durum 28 X A. elongatum 70..
J\ polonkum 28 X A. elongatum 70.
7'. aestivum 42 X A. elongatum 70 —
T. durum 28 X A. glaucum 42.
T. polonkum 28XA. glaucum 42.._.
7\ <Ks/i'»Em 42 x A. g/aucum 42
2'. dkoccum 28 X A. glaucum 42.
By whom made
F. Nilsson and G. Nilsson-
Leissner.1
V. J.Sandoi
.do..
.do..
L. E. Kirk and R. McVicar '.
_do_.
.do..
.do.,
.do.,
.do.
Institution
Swedish Seed Association, Svalof.
Sweden.
XT. S. Department of Agriculture,
Bureau of Plant Industry,
Washington, D. 0.
....do
.do-
Central Experimental Farm, Ot-
tawa, Canada.
....do
....do
.-..do
-...do
....do ...
T. M. Stevenson and \\. J.
White.'
T. dkoccum 28 X A. elongatum no. 820,
70.
T. dkoccum 28 X A. elongatum no. 1083,
70.
T. durum 28 X A. glaucum 42
T. durum 28 X A. elongatum no. 820, 70.
T. durum 28 X A. elongatum no. 1083, 70.
T. aestivum 42 X A. glaucum 42...
.do.
.do..
.do.,
.do..
.do..
T. aestivum 42 X A. elongatum no. 820,
70.
T. aestivum (Kharkov) 42 X A. elan- I do.
gatum no. 1083, 70.
\rmstrong (/)_
....do
...do.
...do
—do
...do
...do
...do..
Dominion Forage Crops Labora-
tory, Saskatoon, Saskatchewan,
Canada.
....do
—do..
.do. .. .
— do
..-.do
Central Experimental Farm, Ot-
tawa, Canada.
....do
Date made or
reported
1035.
1935..
1935...
1935-
1936..
1935.
193.5, .
1935..
1935.
1935.
1935.
1935.
1935.
1935-
1935-36-
..do_.
...do-
..do..
..do-
_do-
-do..
.do-
1935-30
_. 1935-36
I
. I 1935-30.
Remarks
Cross reported successful, but no description
given.
90 flowers pollinated; 7 seeds obtained; 4 seeds
planted, 2 percent of which produced plants.
54 flowers pollinated; 9 seeds obtained; 7 seeds
planted, 6 percent of which produced plants.
2,128 flowers pollinated; 398 seeds obtained;
140 seeds planted, 10.5 percent of which
produced plants.
Cross successful; Fi hybrids male sterile; may
be backcrossed on Triticum parent.
Do.
Do.
Do.
Do.
Cross successful; Fi hybrids showed partial
fertility.
Cross reported successful, but fertility of Fi
not yet determined.
Do.
Do.
Do.
Do.
Do.
1,190 flowers pollinated; 1,414 seeds obtained;
34.0 percent successful.
1,391 flowers pollinated; 538 seeds obtained;
38.7 percent successful.
190 flowers pollinated; 3 seeds obtained; 1.5
percent successful.
1,224 flowers pollinated; 394 seeds obtained;
32.2 percent successful.
1935-30 | 345 flowers pollinated; 11 seeds obtained; 3.2
percent successful.
164 flowers pollinated; 12 seeds obtained; 7.3
percent successful.
1,041 flowers pollinated; 122 seeds obtained;
11.7 percent successful.
239 flowers pollinated; 25 seeds obtained; 10.5
percent successful.
328 flowers pollinated; 45 seeds obtained; 13.7
percent successful.
.1 1935-30.
1935-36..
1935-36.
1935-36.
'£
las
to
©
©
VO
io
--)
T. durum 28 X A. elongatum 70..
T. aestivum 42 x A. elongatum 70.
T. aestivum X A. glaucum 42
T. aestivum 42 X A. intermedium 42..
T. sphaerococcum 42 X A. intermedium
42.
T. cempactum 42 X ^4. intermedium 42..
7\ dicoccoides 28 X ^4. intermedium 42__.
T. dkoccum 28 X -4- intermedium 42
OT. durum 28 X -4. intermedium 42
T. polonicum 28 X ^4. intermedium 42...
T. pcrsicum 28 X ^4- intermedium 42
T. monococcttm 14 X A. intermedium 42.
T. aestivum 42 X ^4. elongatum 70 _.
T. sphaerococcum 42 X *4. elongatum 70.
T. compactum 42 X A. ehngatum 70- .
5T. dkoccoides 28 X ^4. elongatum 70
r. dkoccum 28 X -4. elongatum 70
T. durum 28 X .4. elongatum 70
IT. turgidum 28 X ^4. elongatum 70
7\ persicum 28 X ^4- elongatum 70
T. momococcttm 14 X -4. elongatum 70___
Vakar (34).
_do..
.do..
Verushkin (35) _
.do..
_do_
_do.
.do..
_do_.
_do_.
_do_.
_do_.
_do-
_do_.
.do...
_do..
-do_.
.do..
.do-
-do-
_do_.
1 Reported in reply to the Yearbook questionnaire, 1936.
Siberian Institute for Scientific Re-
search of Grain Management,
Union of Soviet Socialist Re-
publics, Omsk.
do
_do_.
Ccntral Station of Plant Breeding
and Genetics, Saratov, Union of
Soviet Socialist Republics.
...do
_do-
.do_.
_do_.
_do_.
..do.
-do_.
-do..
_do_.
.do-
.do..
_do_
.do.
.do..
.do..
_do_.
1935-
1935-
1935_
1935.
1935.
1935-
1935.
1935..
1935_ .
1935..
1935- .
1935-
1935- .
1935- .
1935. .
1935. .
1935...
1935..
Success with cross; 49 somatic chromosomes
in the Fi hybrid.
Success with cross; 56 somatic chromosomes
in the Fi hybrid.
Success with cross; 42 somatic chromosomes
in the F! hybrid.
3,062 flowers pollinated; 1,248 seeds obtained;
40.7 percent successful.
80 flowers pollinated; 24 seeds obtained; 30
percent successful.
80 flowers pollinated; 10 seeds obtained; 12.5
percent successful.
180 flowers pollinated; 52 seeds obtained; 28.8
percent successful.
128 flowers pollinated; 39 seeds obtained; 30.5
percent successful.
1,207 flowers pollinated; 564 seeds obtained;
46.7 percent successful.
48 flowers pollinated; 21 seeds obtained; 43.7
percent successful.
256 flowers pollinated; 131 seeds obtained;
51.2 percent successful.
86 flowers pollinated; 11 seeds obtained; 16.3
percent successful.
2,136 flowers pollinated; 937 seeds obtained;
43.8 percent successful.
59 flowers pollinated; 31 seeds obtained; 52.5
percent successful.
18 flowers pollinated; 3 seeds obtained; 16.6
percent successful.
54 flowers pollinated; 22 seeds obtained; 40.7
percent successful.
328 flowers pollinated; 93 seeds obtained; 28.5
percent successful.
1,128 flowers pollinated; 469 seeds obtained;
41.5 percent successful.
24 flowers pollinated; 10 seeds obtained; 41.5
percent successful.
70 flowers pollinated; 26 seeds obtained; 37.1
percent successful.
24 flowers pollinated; 0 seeds obtained; 0.0
percent successful .
5^
Co
Ci
t*1
t-<
t-<
©
CM
CO
Ci
Co
Co
C*1
Co
o
1094
YEARBOOK, 1937
Table 5. — Chromosome numbers of various grasses
Genus and species l
Aeluropus litloralis var. dasyphylla
Trautv.f - -
A. tiitoratis (Gouan) Parl.f
Agropyron acutum (DC.) Koem.
and Schult
A. aegilopoides Drobov
A. caninum (L.) Beauv
A. ciliare (Trin.) Franch
A. cristatum (L.) Gaertn
A. cristatum (Fairway strain)
A. dagnae Grossh _
A. dasystachyum (Hook.) Scribn...
A.desertorum (Fisch.) Schult.t
A. elongalum (Host) Beauv. f
A. glaucum (DC.) Eoem.' and
Schult _ :
A. grifftihsii Scribn. and Smith
A. intermedium (Host) Beauv.
(See A. obtusiusculum.)
A. japonicum Honda. =>A. japon-
ense Honda
A.junceum (L.) Beauv
A. mutabile Drobov
A. obtusiusculum Lange=/L. inter-
medium
A. orientate (L.) Roeni. and Schult.
A. paucijlorum (Schwein.) Ilitchc.
A.prostratum (Pall.) Beauv
A. pungens (Pers.) Koem. and
Schult
A. repens (L.) Beauv
Do -
A. rickardsoni Scbrad.=X. sub-
secundum.
A. semicostatum (Steud.) Nees
A. sibiricum (Willd.) Beauv. t
A. smithii Rydb._ ..
A. smithii var. molle (Scribn. and
Smith) Jones
A. spicatum (Pursh) Scribn. and
Smith __.
A. subsecundum (Link) nitchc.
(See A. ricbardsoni.)
A. tunguscense Drobov
A. villosum (L.) Link
Agrostis alba L._
A. nebulosa Bois. and Reut
A. tenuis Sibth. (See A. vulgaris.)
A. verticiUala ViU...
A. vulgaris With. =A. tenuis
A. spica-venti L. (See Apera spica-
venii.)
Alopecurus aequalis Sobol. (See
A. fulvus.)
A. agrestis li.=A. myosuroides
A. alpinus J. E. Smith, vnr.elatva
Koin
A. fulvus J. E. Smttht-.il. aequalis.
A. genicutatus L
A. myosuroides Huds. (See A.
agrestis.)
A. pratensis L
So-
matic
chromo-
Refer-
some
ence 3
number
(21!)!
20
(5)
CO
(5)
35
(40)
14
(4)
28 a
(42)
28
(39)
28 c
(41)
14*
W
Ma
(42)
28
(42)
28
(42)
70
(42)
42
(42)
28
(42)
28
(39)
28 a
(42)
28
(4)
42
(42)
28
(3)
28 a
(42)
14
(4)
42* a
(42)
42 b
(42)
28
(4)
28
(41)
42
(39)
28 b
(3)
50 a
(42)
28, 56
(42)
14
(42)
28
(4)
14*
(42)
42 a
(3)
14 a
(1)
28
(4)
28
(3)
14 a
(3)
70
(4)
14
(24)
23 a
(3)
28 d
(3)
Genus and species i
So-
matic
chromo-
some
number
(2n)»
Ammophila brevitigutata Fernald--.
Andropogon annulatus Forsk.f
A. condyiotticliusllouhst. (See A.
pijUatherus.)
A. elliottii Cliapm
A.furcatus Muhl
A. gryltus li.=Iihaphts gryllus
A. halepensis (L.) Brot. (See also
Sorghum halepense)
A. halepensis var
A. intermedins R. Br
A. nardus L. =°Cymbopogon nardus.
A. piptatherus Hack.=^4. condylo-
Irichus
A. purpureo-sericeus Hochst-t=
Sorghum purpureo-sericeum
A. saccharides Swartz
A. scoparius Michx
A. sorghum (L.) Brot. = 6'or(/Aum
vulgare
A. sorghum Brot. var. sudanense
Piper = Sorghum vulgare var.
sudanense _
A. versicolor = Sorghum versicolor...
Anthephora hermaphrodita (L.)
Kuntze __ _
Anthoxanthum aristatum Boiss
A. odoratum L _ _
Apera spica-venti (L.) Beauv. =
Agrostis spica-venti
Apluda mutica L
A. mutica L
A rislida adscensionis L_._
Arrhenalherum elatius (L.) Mert.
and Koch
Arthraxon ciliaris Beauv. subsp.
langsdorfii (Trin.) Hack
A. hispidus (Thunb.) Makino
Arundinariafortunei (Van Jloutte)
Rivieret
A. glaucescens (Willd.) Beauv
A. hindsii Munro
A. pygmaea Kurz
Arundinella anomala Steud ...
Arundo donax L
Asprella hystrix Willd. \=IIystrix
patula
Atropis distans (L.) Griseb.=P«c-
cinellia distans
A. distans (L.) Griseb
Do
Avena atgeriensis Trabut ..
A. barbala Brot.t
A. bruhnsiana Gruner
A. brevis Rotht
A. byzantina O. Kocht
A. clauda Dur
A.falua L
A. flavescens L.= Trisetnm Jla-
vescens
A. ludovkiana Dur.t
28*
40«
20
70 «
40
40 f
20
5 70
20
40
40
00
40 a
20 a
10 a
18
10
20b
14
40 a
20
22
28* C
40
40
48
70-74
48
54
30
100+a
28
42
28
14
42
28 d
14
14 b
42 a
14 a
42 a
28
42
Refer-
ence3
('■))
(23)
(19)
(10)
(4)
(3)
(21)
(3)
(27)
(4)
(33)
(4)
(10)
(28)
(14)
(22)
(3)
(3)
(3)
(4)
(3)
(19)
(5)
(2)
(3)
(3)
(19)
(3)
(52)
(19)
(4)
(4)
(3)
(4)
(47,48)
(4)
(25)
(25)
(12)
(10)
(25)
(<i0)
(25)
(37)
(20)
' Authorities for the botanical names used have been corrected to agree with the International Code and
the U. S. Department of Agriculture style. Those names for which no authority was given in the original
are indicated by a dagger (t) and the recognized authority for the name has beeu inserted, but this does not
mean that the grasses were correctly identified by the cytologist.
1 Letters following chromosome numbers denote the number of times this number has been verified by
other authors than the one indicated by the reference in the last column. a = l, b=2, e=3, d=4, e=5, f=6,
g=7. An asterisk (*) indicates those reported as the "n" number, the number here given being double
that reported.
3 Numbers in parentheses refer to References for Chromosome Numbers, p. 1099. Where a number has
been verified by several workers, only the first report of that number is cited.
' W. N. Myers, personal correspondence.
* About.
MISCELLANEOUS GRASSES 1095
Table 5. — Chromosome numbers of various grasses — Continued
Genus and species
So-
matic
chromo-
some
number
(2fl)
A. nuda L
A. saliva L
A. sterilis L
A. strigosa Schreb.t subsp. abys-
sinica (Hochst.) Hausskn.f
A. strigosa Schreb__
A. wiestii Steud.t
Beckmannia erucaeformis (L.) Host.
Boissiera bromoides Hochst. and
Steud.t -
B.pumilio (Trin.) Slapf.
Bouteloua gracilis (H. B. K.) Lag.t
B. oligostachya (Nutt.) Torr.=
Bouteloua gracilis __
Brachiaria erucaeformis (J. E.
Smith) Griseb. (See Pankum
erucaeforme.)
B. mutica (Forsk.) Stapf
Brachypodium distachyon (L.)
Beauv. (See Trachynia di&ia-
chya.)
B. pinnatum (L.) Beauv. t
B. sylvalkum (Huds.) Beauv
Briza elatior S. Smith
B. maxima L__ _
B. media L_ _ -
B. minor L _ _.
Bromus abolinii Drobov _.
B. albidus Bieb
B. arduennensis Dum
B. arvensis L_
B. auslralis R. Br.t
B. breviarislalus Buck]
B. brizaeformis Fiscb. and Mey
B. cappadockus Boiss. and Bal
B. carinatus Hook, and Arn
B. carinatus var. hookerianus
(Thurb.) Shear—
B. cartharticus Vahl. (See B.
unioloides.)
B. ciliatus L_ _
B. ciliatus L _
B. erectus Huds
B. erectus Huds. subsp. eu-ereclus
Asebers. and Graeb
B. inermis Lcyss
B. inermis Leyss
B. intermedins Guss _- .
B. japonicus Thunb
B. kalmti A. Gray
B. macrostachys Desf..-.
Do
B. madritensis L
Do _ _
B. marginatus Neos
B. moilisli
B. pacificus Shear
B. polyanthus Seribn
B. pumpellianus Scribn
B. purpurascens T>el.=B.tubens-.
B. ramosus Huds...
B. rigidus Roth. (See B. villosus) .
B. rigidus var. gussonii. (Sco B.
villosus var. gussonii.)
B. rubens L. (Sec B. purpur-
ascens.)
B. secalinus L
B. silchensis Trin. t--
B. sguarrosus 1j -.
B. sterilis L
B. tectorum L
42
42 a
42 e
28
14 e
14 c
14
28
14
42
40
28 a
42
14
14
14 a
Refer-
ence
(20)
(25)
(20)
(12)
(25)
(20)
(4)
(47, 48)
(4)
CO
(4)
(19)
28
(24)
18
(3)
14-17
(4)
14 a
(3)
14 a
(3)
10 a
(3)
14
(4)
28
(4)
14
(47,48)
14 a
(3)
28
(47,48)
50
(47,48)
14
(3)
42
(47,48)
56 a
(47,48)
14
(47,48)
56
(4)
14
(47,48)
42
(47, 48)
56* a
(24)
50
<3)
42 a
(47,48)
14
(3)
14 a
(3)
14
(47,48)
28
(3)
14
(47, 48)
28
(4)
42
(47, 48)
56 a
(4)
28 a
(3)
42
(47,48)
42
(*7, 48)
42
(47,48)
28 a
(47,48)
14
(47,48)
(3)
(47, 48)
(47, 48)
(47, 48)
(3)
Genus and species
So-
matic
chromo
some
number
(2n)
B. unioloides II. B. K.=Ji. cath-
ariicus — _
B. varkgalus Bicb
B. villosus Forsk.t=i3. rigidus-
B. villosus var. gussonii Aschcrs.
and Graebn. t=.B. rigidus var.
gussonii-
B. virens Buckl.=_B. carinatus
Buchloi dactyloides (Nutt.) Engelm.
Oalamagrostis arundinacea (L.)
Roth __._
C. epigeios (L.) Roth _
C.negleda (Ehrh.) Qacrtn.t
Catabrosa auqatica (L.) Beauv
Cenchrus barbalus Schum. (Seo
C. catharticus.)
C. brawnii Roem. and Schuit.
(See C. inftexus.)
C. catharticus Dc).t=C. barbatus...
C. echinatus L
C.infiexus R. Br. =C brownii
C. myosuroides H. B. K
C.tribuloides L
Cenlotheca latifolia (Osbcck) Trin..
Chaeturus fasciculatus Link
Chloris acuminata Trin. = C. disti-
chophylla
C. barbata (L.) Swartz=C. infiata--
C.cucullata Bisch ...
C. distkhophylla Lag. (See C.
acuminata.)
C. gayana Kunth.
C. inflata Link. (See C. barbata.)
C. submutica H. B. K__
C. truncata R. Br _
Cinna arundinacea L__
Ckistagen.es serotina (L.) Kcng.
(Seo Diplachne serotina.)
Coix lacryma-jobi L
Cornucopiae cucullatum L
Corladeria argenlea (Nees) Slapf. =
C selloana
C. selloana (Schuit.) Aschers. and
Graebn. (See O. argentea and
Gynerium argenteum.)
Corynephorus canescens (L.) Beauv.
Cymbopogon nardus (L.) Rcndlc.
(See Andropogon nardus.)
Cynodon dactylon (L.) Pcrs
C. dactylon (L.) Pors
Cynosurus balansae Coss. and Dur.
C. cristatus L-
C. echinatus L
Vactylis aschersoniana Graebn. t
D. glomerala L
Dactyloctenium aegi/ptium (L.)
Richt.t—
Deschampsia caespitosa (L.) Beauv.
Desmazeria sicula (Jacq.) Dum
Dlgitaria enlis (Kipp.) Stapf-
D. sanguinalis (L.) Scop
B. horizontals \Vflld.t
Dinebra retroflexa (Vahl) Banz
Diplachne serotina (L.) Linkf=
Cleistogenes serotina
Echinaria capitata (L.) Desf
Echinochloa crusgalli (L.) Beauv...
E. crusgalli (L.)Beauv. var. edulis
Hitchc. = E. crusgalli var.
frumenlacear
28 a
42
42 a
28
»70
»70
21 (?) a
34
34
34
• 70
34 a
24
14
40
20
40
20 a
20 a
14
56*
Refer-
ence
(47, 48)
(47, 48)
(3)
(47,48)
(47,48)
(4)
, «)
(47,48)
(3)
(3)
(3)
(3)
(3)
(4)
(3)
(3)
(3)
(3)
(3)
(4)
(3)
(3)
(4)
(3)
(20)
(4)
36
(3)
30
(10)
14
(3)
14 a
(3)
14 a
(3)
14* b
(24)
28 d
(11)
48
(3)
28
(3)
14 b
(3)
54
U«>
28*
(1(1)
36
(3)
20
(3)
40
(4)
18
(4)
42*
(10)
(10)
' About.
6 L. M. Humphrey; personal correspondence.
1096 YEARBOOK, 1937
Table 5. — Chromosome numbers of various grasses — Continued
Genus and species
So-
matic
chroino
some
number
(27!)
E. crusgalli var. frumentacea
(Poxb.) Wight. (See E. crus-
galli var. edulis.)
E. frumentacea (Roxb.) Link = K,
crusgalli var. frumentacea
FJirharta panicea Sm
Eteusine caracana (L.) Gaerin
E.indica (L.) Gaorln
E.tristachya (Lam.)
Etymus canadensis L
E. caput-medusae L. (Sec Horde-
urn caput-medusae.)
E. curvatus Piper = E. virginicus
var. submul icus
E. dahuricus Turcz
E. giganteus Vahl
E. sibiricus L
E. virginicus var. submnticus nook.
(See E. curvatus.)
Eragrostisabyssinica (Jacq.) Link.f.
E. albida Hitehc
E. aspera (Jacq.) Ncls
E. cambessediana (Kuntli) Stead...
E. capensis (Thunb.) Trin
E. cilianensis (All.) Link. (See
E. megastachya.)
E.japonica (Thunb.) Trin. [Trin.]
E. megastachya (Koel.) Link = E.
cilianensis
Eragrostis mexicana (Lag.) Link
E. pallescens Hitehc
E.spectahilis (Pursli) Steud.f
E. tef (Zuec.) Trotter = E. abys-
sinica
Erianthus arundinaceus (Rctz.)
Jcswietf
E. japonicus (Thunb.) Beauv. =
Miscanthus japonicus
E. ravennae (L.) Beauv
Eriochloa tillosa (Thunb.) Kunth..
Euchtaena mexicana Schrad
E. perennis Hitehc
Eulalia japonica (Thunb.) Trin.
= Miscanthusjaponicus
Festuca amethystina L
F. arenaria Lam.t
F. arundinacea Sctarcb. = F. etatior
var. arundinacea
F.bromoidesZi. — F. dertonensis
F. dantkonii Aschers. and Graebn..
F. danthonii Aschers. and Graebn.
var. imberbis (Vis.) Aschers. and
Graebn...
F. dertonensis (All.) Aschers. and
Graebn
F. duriuscuta L. = F. ovina var.
dvriuscula
F. etatior L._
F. etatior var. arundinacea (Schreb.)
Winim. (See F. arundinacea.)
F. etatior L. subsp. arundinacea
var. cirtensis St. Yves = F.
etatior var. arundinacea
F. etatior L. subsp. arundinacea
Hack. var. genuina Hack. = F.
etatior var. arundinacea
F. etatior L. subsp. arundinacea
Hack. var. uechtritzi'ina (Wies-
baur) Hack. = F. etatior var.
arundinacea
F. etatior I,, subsp. pratensis Hack.
var. apennina Hack. = F. etatior.
30
(19)
24*
(4)
36 b
(3)
18
(4)
18
(3)
28 a
(3)
28
(4)
42
(3)
28
(4)
28 a
(3)
40
(3)
40
(18)
20
(4)
20
(18)
40
(3)
20
70
42 b
23
42 a
(3)
20
00
80
42
(3)
(3)
(18)
(»)
40
(3)
0,00
(8)
00
00
54
20 b
40 c
(7)
(7)
(3)
(28)
(32)
3(5
28
42
(3)
(47,48)
(37)
42 c
14
28
(44)
(47,48)
(4)
42
(3)
14
(44)
42*1)
14 g
(9)
(37)
(30)
(31)
(47, 48)
(47,48)
Genus and specios
F. etatior var. pratensis (ITuds.) A.
Gray = F. etatior
F. etatior var. pratensis subvar.
typica = F. etatior
F.geniculata Cav.fKL.) Oav.l
F.gigantea (L.) Vill
F. granatensis Boiss. = F. scar hsa
Lag
F. loliacea Uuds
F. mairei St. Yves
F. maritima L
F. montana Savi...
F.myuros L
F. myuros L
F. orina L
F. orina L. subsp. alpina (Suter)
Wirnm. and Grab
F. orina L. subsp. eu-ovina Hack.
var. duriuscuta Hack. = F.
orina var. duriuscuta
F. orina L, subsp. eu-ovina Hack.
var. duriuscuta Koch, subvar.
gertiuna Koch. = F. ovina var.
duriuscuta
F. ovina L. subsp. eu-ovina Hack.
var. duriuscuta Hack, subvar.
genuina Hack. = F. ovina var.
duriuscuta
F. ovina L. subsp. eu-ovina Hack. =
F. ovina _
F. ovina L. subsp. indigesta Hack.
var. titardieri St. Yves=F. o»im
var. indigesta
F. ovina L. subsp. sulcata Hack.
var. duvalii St. Yves=F. ovina
var. sulcata.
F. ovina L. subsp. sulcata Hack,
var. panciciana Hack.=F. ovina
var, sulcata
F. ovina var. duriuscuta (L.)
Koch. (See F. duriuscuta.)
F. ovina var. tenuifolia (Sibth.)
Sm 1
F. rubra L
F. rubra L. subsp. eu-rubra var.
genuina Hack.=F. rubra
F. rubra L. subsp. heterophylla
(Lam.) Haek.=F. rubra var.
heterophylla (Lam.) Mutal
F. rubra L. subsp. nevadensis Hack.
var. hackelii Lit. and Maire
subvar. brevifotia Lit. and Mairo
=F. rubra var. nevadensis
F. rubra L. subsp. violacea (Gaud.)
Hack. = F. rubra var. violacea
F. scariosa Lag. (See F. grana-
tensis.)
F. sibirica (Gri&eh.) Hack. (Seo
Leucopoa sibirica.)
F. silvalka Vill
F. spadicea L.._
/'. spadicea var. aurea (Lam.)
Richtcr. (See F. spadicea var.
genuina subvar. aurea.)
F. spadicea var. genuina subvar,
aurea = F. spadicea var. aurea
F. tenuifolia Sibth. \=F. ovina var.
tenuifolia
F. triflora Desf _.
F. varia Haenke. (See F. varia
subsp. eu-varia var. genuina.)
So-
matic
chromo-
Refer-
some
number
(2«)
ence
14*g
(13)
28
14
42 b
(31)
(4)
(30)
14 a
14
28 a
14
11 a
14
42 a
50*
(30)
(43)
(30)
(4)
(30)
(3)
(47, 48)
(9)
14 b
(31)
28
(47, 48)
42 b
(30)
70
(47,48)
14 b
(30)
70 a
(30)
42 a
(30)
28
(47,48)
28
42 *b
(31)
(»)
£3
(30)
42 a
(30)
70 a
(30)
11
(47, 48)
42 a
14
(47,48)
(44)
2S
(31)
14
14 a
(37)
(30)
" L. M. Humphrey, personal correspondence.
MISCELLANEOUS GRASSES
Table 5. — Chromosome numl/ers of various grasses — Continued
1097
Genus and species
F. varia var. scoparia subvar. ker-
fieri St. Yves ..
F. varia Haenke subsp. eskia
(Rain.) St. Yves=i<\ varia var.
eskia
F. varia var. eskia Gren. and Godr.
(See F. varia subsp. eskia.)
F. varia Haenke subsp. eu-varia
Hack. var. genuina Hack. = F.
varia Haenke
Glyeeria aqnatka (L.) Wahlb
G. aqnatica var. arundinacea
Aschers
G. distans Vfah\.=Puccinellia dis-
torts. _
G.fluilans (L.) H. Br
G. nervata Trin.=G. striata
G.plkata Fries
G. speclabilis Mert. and Koeh. = G.
aquatka . —
G. striata (Lam.) Hitchc. (See
G. nervata.)
Gynerium arqenteum (Nees) Slapf.
= Cortaderia selloana
Ilaynaldta villosa (L.) Schur
Ileleochloa scttoenoides (L.) Host...
I-Iierochloe odora/a (L.) Beauv.f
Ilotcos lanaf-us L
//. mollis L
lTordeum bvtbomm L
//. caespitosum Scribn
Ilordeum caput-medusae (L.) Coss.
andDur. = Elymuscaputmedusae.
Tl.jubatum L_._
ll.jubatum L.f
//. murinum L
//. murinum L._ _
11. nodosum L
II. nodosum Lf
II. pusillum Nutt.f
II. secafinum Schreb
//. silvatkum Huds
II. spontaneum C. Koch
llyslrhe patula Moench. (See
Asprclla hyslrix.)
Imperata arundinacea Oyrillo
Ischaemum anthephoroides Mir|
Koeleria cristata (L.) Pers.
K. ylaiica (Schkuhr.) DC
K. panicea (Lam.) Domin._ _.
K. phleoides (V1H.) Pers
Lagnrns ovatus L —
Lamarckia aurea (L.) Moench
Zeptochloa chinensis (Kotli) Nees...
h. polystachya (It. Br.) Benth
Lepturus cylindrkus (Willd.) Trin.
I., jitiformis (Roth) Trin.
L. incurvatus Trin. =Pholinrus in-
curvus
L. pannonkus (Host) Kunth.=
Pholiurus pannomcus
Leucopoa sibirica Griseb. = Festuca
sibirka
Lolinm italicum A. Bi.=L. mulli-
florum..
L. linieolum A. Br.°=£. remotum..
L. multiflorv.ru Lam
L. perenne L
L. perskum Boiss. and Hohen
L. remotum Schrank. (See L.
linieolum.)
h. temulentum L
Cycurus phleoides H. B. K
matic
chromo-
some
number
(2*0
76
II ti
36
42
14 a
14
28
sj4
14 a
2S c
' 14
28 b
14 a
42
14
14
Refer-
ence
(31)
(47,48)
(47,48)
(47, 48)
(47,48)
(47,48)
(47,18!
(47, 4S!
(47,48)
(3)
(10)
(3)
(4)
(3)
(3)
(47, 48)
(17,48)
(50)
(17)
(2)
(50)
(2)
(49)
(17)
(50)
(50)
28 b (47.48)
28 (47,48)
14 a (40)
II a
14
14 b
14* e
14
14 a
40
(7)
(28)
(4)
(3)
(4)
(3)
(4)
(3)
(3)
(3)
(19)
(3)
(3)
(3)
(3)
(3)
(15)
(13)
(13)
(15)
(15)
(4)
Genus and species
So-
matic
chromo-
some
number
(2n)
18 b
18
18
18 a
36 a
14
28
28
38
64
42* a
26
»40
40
42
40
26
72
72
54
24
48
24
24
18
54
54* a
18
>48
18* a
42
36
36
54
36
18* a
18*
18*
18*
40* a
20*
40
20* a
20-23
80
Refer
dice
Manisuris glandulosa (Trin.)
Kuntze. (See Rottboellia gland-
ntosa.)
(3
Af. cltiata L. (See AI. ciliata Guss.
var. eligulala.)
Af. ciliata Guss. var. elignlata=
(3
M. mkrantha Bois.,. and Hohen
(3
(3
(3
Miboraverna (Pers.) Beauv.f
Aiilium ef/usum h -.._
(3
(3
(3
Aliscanlhus japonkus (Thunb.)
(8
AX. saceharifer (Anderss.) Benth...
09
(10
Alonerma cylindrica (Willd.) Coss.
and Dur.= Lepturus cylindrkus..
Afvhlenbergia glomerata (Willd.)
Trin.= Muhtenbergia racemosa...
(4
(3
(4
(«
Al. racemosa (Michx.) B. S. P.
(See Aluhlenbergia glomerata.)
AT. sylvatica Torr. (Soo Aluhlen-
bergia umbrosa.)
M. umbrosa Scribn. = Aluhlenbergia
(4
Kardus strkta L
Kassella trichotoma (Nees) Hack.
(Seo Urachne tilchatoma.)
Oplismenus bntniartii (Retz.)
(3
(19
(4
O. undulatifolius (Ard.) Roem. and
Schult.f
(4
(16
(16
Oryzopsis miliacea (L.) Benth. and
Hook.f
(3
(3
(3
P. erusgalli L.= Eehinochloa crtis-
(3
(10
(3
P. erucaeforme J . K. Smith = I4rach-
P. erusgalli var. frurnentaceum
(Roxb.) Trimcn.f=/'.cJi!KOcWoii
erusgalli vor.frumentacea. .
(45
(10
(45
(4
(45
P. ptieatum Lam. = Setaria plicata..
P. sanguinale h.=Digitaria sangui-
(3
(3
P. scribnerianum Nash....
P. sphaerocarpon Ell. . ... .. ... .
P. subvillosum Ashe.
P. tsugetorum Nash _.
GO
(10
(10
GO
(Si
P. muhlenbergii Nash = Paspalum
pubescens ... _
P. pubescens Muhl. (See P. muh-
lenbergii.)
(10
(3
P. stolonifernm Bosc.f.. _
P.virgatum'L
(35
(f
(4
> About.
138904° — »7 70
6 L. M. Humphrey, personal correspondence.
1098 YEARBOOK, 1937
Table 5. — Chromosome numbers of various grasses — Continued
Genus and species
So-
matic
chromo-
some
number
(27!)
Penicillaria spicata (L.) WiHd.=
Pennisetum glaucum .--.
Pennisetum cenchroides (L.) Rich
= Pennisetum ciliare
P. ciliare (L.) Link. (See P.
cenchroides.)
P. clandestinum Chiov.t
P. glaucum (L.) R. Br
P. longistylum Hochst
P. macrourum Trin
P. orientate L. Rich
P. ruppelii Steud.t
P. setosum (Swartz) L. Rich
P. typhoideum L. Rich.t=P. Qlau-
cum —
P. villosum R. Br
Phaenosperma globosa Munro
Phataris arundinacea L
P. arundinacea L
P. arundinacea L. var. picta L
P. canariensis L
P. canariensis L
P. minor Retz
P. paradoxa L
P. tuberosa L
P. tuberosa var. stenoptera (Hack.)
Hitchc.
Phleum asperum Jacq.t
P. boehmeri (L.) Wibel
P. michelii All
P. paniculalumSads.var.annuum
(Bieb.) Griseb
P.phteoides (L.) Karst-
P. pratense L
Pholiurus incurvus (L.) Schinz and
Then. (See Lepturus incurvatus.)
P. pannonicus (Host) Trin. (See
Lepturus pannonicus.)
Phragmites communis (L.) Trin___
P. communis (L.) Trin
P. communis (L.) Trin
P. communis (L.)Trin
P. communis (L.) Trin.t
Phyllostachys edulls (Carriere)
Lehaief
P.flexusa A. and O. Riviere
P. heterocycla Mitfordt .--
P. "matiacum" error for P. marli-
acea Mitford?
P. nigra Munro
P. reticulata Koch
Poa alpina L
P. alpina L —
P. alpina L. var. badensis (Haenke)
Mert. and Koch
P. annua L
Do
P. bulbosa L
P. caesia J. B. Smith
P. compressa L
Do
Do
P. glauca Vahl
P. nemoralis L
Do
Do
P. palustris L
Do
P. palustris L. var. fertilis (Host)
Aschers. and Graebn
P. palustris L
36 a
14*
45
54
36
27
54
14
45
24
14* d
28 a
28*
12 b
28
28
14
28
28
28b
14 a
14*
28
14
42 b
54 a
36 a
48
48
54 a
48
70-74
48
48
32-34
22-38
42
28 a
14
42
42
42 a
56
14
70
28
56
42 a
42 a
20
28
70
Refer-
ence
(4)
(4)
(29)
(23)
(4)
(4)
(3)
(4)
(3)
(45)
(4)
(4)
(9)
(37)
(9)
(3)
(38)
(3)
(4)
o
(«)
(3)
(3)
(24)
(3)
(19)
(3)
(3)
(51)
(19)
(4)
(51)
(52)
(52)
(52)
(3)
(52)
(52)
(3)
(36)
(47,48)
(3)
(44)
(47, 48)
(47, 48)
(4)
(47, 48)
(44)
(3)
(3)
(36)
(47, 48)
(47, 48)
(8)
(3)
(38)
Genus and species
So-
matic
chromo-
some
number
(27!)
P. pratensis L
Do
Do
Do
Do --
P. pratensis var. angustifolia (L.)
Gaud.t= -P- pratensis L—
P. pratensis var. angustifolia (L.)
Gaud.t=-P. pratensis L__- •
P. pratensis var. angustifolia (L.)
Gaud.f=-P. pratensis L
P. sudetica Haenke
P. trivialis L
P. violacea Bell
Pollinia imberbis Nees
Polypogon littoralis (With.) J. E.
Smith
P. monspeliensis (L.) Desf
Polytoca macrophylla Benth
Psilurus aristatus (L.) Lange
Puccinellia distans (L.) Pari. (See
Atropis distans and Qlyceria dis-
tans.)
Rhaphis gryllus (L.) Desv. (See
Andropogon gryllus.)
Rottboellia glandulosa Trin. = AfaTH-
suris glandulosa
Schismus barbatus (L.) Chase.
(See S. calycinus.)
S. calycinus (Loefl.) Duval-Jouvet
= S. barbatus
Sclerochloa dura (L.) Beauv
Schleropoa rigida (L.) Griseb
Sesleria argenlea Savi
S. autumnalis (Scop.) F. Schultz..
5. coerulea (L.) Ard
S. tenuifolia Schrad
Setaria glauca (L.) Beauv.=S.
lutescens
S. italica (L.) Beauv
S. lutescens (Weigel) F. T. Hubb.
(See Setaria glauca.)
S. pticata (Lam.) T. Cooke. (See
Panicum plicatum.)
S. verticillata (L.) Beauv
S.viridis (L.) Beauv
Sinobambusa tootsik Makino
Sorghastrum nutans (L.) Nash
Sorghum drummondii (Nees)
Hack. = /Sorp/iM7» vulgar e var.
drummondii
S. effusus (Hack.) Karper and
Chisholm
S. halepense (L.) Pers
S. halepensis var. miliformis
(Schult.) Karper and Chisholm-
S. hewisoni (Piper) Longley -.
S. purpureo-sericeum (Hochst.)
Schweinf and Aschers. (See
Andropogon purpureo-sericeus.)
S. vulgare var. drummondii (Nees)
Hitchc. (See S. drummondii.)
S. vulgare var. sudanense (Piper)
Hitchc
5. versicolor Anderss
S. verticilliflorum (Steud.) Stapf...
S.virgatum (Hack.) Stapf
S. vulgare Pers. (See Andropogon
sorghum.)
Spartina alterniflora Lois
S. cynosuroides (L.) Roth
56b
42
28-85c
49-85
48-90
28
56
70
14
14 a
28
40
42
28
40
28
54
12
14
14 a
28
28
28*
42
36
18 b
18
48
40*
20
40
40
20
20
10 a
20
20
70
80-90
• About.
e L. M . Humphrey, personal correspondence.
' B. L. Sethi, personal correspondence.
MISCELLANEOUS GRASSES 1099
Table 5. — Chromosome numbers of various grasses — Continued
Genus and species
So-
matic
chromo-
some
number
(2«)
S. michauziana Hitchc.=S. pedi-
nata.
S. pectinata Link. (See 6*. mich-
auxiana.)
S. schrcberi F. Gmcl
S. slricla (Ait.) Roth
*%'. townsendii H. and J. Groves
Sphenopus daarkatus (Gouan)
Heiehb
Sporobolus btrU'.rotnms (Trin.)
Hitchc. and Chaset=<S. pohetii.
S. diaiidrus (Retz.) Beauv...
S. indicus (L.) R. Br
S. poirdii (Eoem. and Schult.)
nitchc. (See S. berteroanus.)
S. tenuissimus (Mart.) Kuntze —
Slipa capillafa Tj
S. lessingiana Trin. and Rupr
S. papposa Nees
$. pulcherrima C. Koch
S. sibirica (I/.) "Lam
S, stenophylla Czern
S. ucrainka P . Smirn
Themeda arguens (L.) Hack
T. jorskalii Hack
Trachynia distachya (L.) Link.=
Brachypodium distachyum
30
Refer-
ence
(9)
»40
(»)
50
(21)
120
(21)
12
(3)
36
(4)
36
(3)
18, 36
(3)
40
(19)
44
(3)
44
14)
42-44
CI)
44
(1)
24
CD
w
44
44
(4)
20
<8>
60
(4)
(4)
Genus and species
So-
matic
chromo-
some
number
(271)
Tragus racemosus (L.) All.f
Trichloris rnendocina (Phil.) Kurtz.
Trichotaena rosea Nees
Triodia fltaa (L.) Smyth. (See T.
flaca.)
T. cuprea Jacq.=T. flam
Tripsacum dadyloides (L.) L
T. dadyloides (L.) L
T. dadyloides (L.) L.f
T. lanceolatum Rupr
T. toaroNash
T. pilosum Scribn. and Merr
Trisetum flavescens (L.) Beauv
T. sibiricum Rupr
Uniola latifolia Michx
Urachne trichotoma (Noes) Trin.=
Nassella Iricholoma
Ventenata macra (Stev.) Boiss. and
BaL ,
Vulpia alopecurus Dum.= Festuca
sp
V. bromoides (L.) S. F. Grayt-
Festuca bromoides=F. myuros or
F. dertonensis
V. myuros (L.) Gmel.t= Fesluca
myuros
V. myuros (L.) Gmel
42
70
30
36, 72
±70
±70
±70
24 b
14
48
14
Refer-
ence
(3)
(4)
(8)
(3)
(32)
(19)
(34)
(32)
(32)
(32)
(4)
(4)
(3)
(3)
(3)
(3)
(47, 48)
(50)
(3)
• About.
REFERENCES FOR CHROMOSOME NUMBERS
(1) Akebbeeg, K.
1936. STUDIES UBEB DIE SAMENBILDUNG BEI POA PBATENSIS L. Bot.
Notiser 1936: 213-280, illus. [English summary, pp. 268-269.
(2) Aase, H. C, and Powers, L.
1926. chromosome numbers in crop plants. Amer. Jour. Bot. 13:
367-372, illus.
(3) Avdulov, N. P.
1928. KARYO-SYSTEMATISCHE UNTERSUCHUNG DER FAMILIE GUAMINEEN.
AUruss. Bot. Kong. Ber. 1928: 65-66.
(4)
1931. KARYO-KYSTKMATISCHE UNTERSUCHUNG DER FAMILIE GRAMINEEN.
428 pp., illus. Leningrad. Trudy Prikl. Bot., Genet, i Selek.
Prilozh. (Bull. Appl. Bot., Genetics, and Plant-Breeding
Suppl. 44.)
(5)
1933. ON THE ADDITIONAL CHROMOSOMES IN MAIZE. Trudy Prikl. Bot.,
Genet, i Selek. (Bull. Appl. Bot., Genetics, and Plant-Breeding)
(2) 2: [101]-130. [Russian, pp. [101J-120; English, pp. 120-130.]
(6) and Titova, N.
1933. ADDITIONAL CHROMOSOMES IN PASPALUM STOLONIFEEUM BOSCO.
Trudy Prikl. Bot., Genet, i Selek. (Bull. Appl. Bot., Genetics,
and Plant-Breeding.) (2) 2: [1651-172. [In Russian. English
summary, pp. 171-172.]
(7) Bremer, G.
1924. de cytologie van het suikbrbiet. hi. de chbomosomen bij
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IMPROVEMENT
OF TIMOTHY
MORGAN W. EVANS, Associate
Agronomist, Division of Forage Crops
and Diseases, Bureau of Plant Industry
J. IMOTHY is the common name applied to the species Phleum
pratense L. About 10 species in the genus Phleum are known, timothy
being the only one under cultivation. They are all native to northern
Europe and Asia with one exception. This one, a native in North
America, is Phleum alpinum L., alpine timothy — a grass that occurs
throughout the mountainous regions in the western United States, and
in the East as far south as the White Mountains of New England
(20, p. 122)}
While timothy is of European origin, it was in the United States that
it was first brought under cultivation. The early history of the crop
in this country is somewhat obscure, but mention of it in colonial days
is not uncommon. In New England it was known as herd's grass at
least as early as the first part of the eighteenth century — probably
earlier. The name "timothy" is said to have been derived from
Timothy Hansen, who obtained seed from New England or New York
and introduced it into Maryland, and possibly into some of the other
southern Colonies, about 1720. Sometime after 1740 an early agri-
culturalist, Jared Elliott, sent seed from Connecticut, under the name
of herd's grass, to Benjamin Franklin. In a letter dated July 16, 1747,
Franklin wrote that the grass sent to him "is grown up and proves
mere timothy" — indicating that it had become fairly well established
as a hay crop in Pennsylvania at that time (21). From then on the
crop increased in use and importance and has received more attention
from agriculturists than any other grass.
In 1909, according to the United States census report, there was a
total of 34,228,000 acres of timothy grown alone and in mixture with
clover. In 1929 this acreage had decreased to 25,547,000, but it still
constituted 37.7 percent of the total acreage used for the production of
all lands of hay in that year. In 1928, the last year in which separate
estimates were made by the United States Department of Agriculture
of the acreage of timothy alone and in mixture with clover, timothy
was grown alone on 8,537,000 acres and with clover on 16,078,000
additional acres.
For feeding horses, of which there are still large numbers, no other
hay has been found as generally satisfactory as timothy. The cost
of the seed is less than that of most meadow and pasture grasses and
it can be sown more readily with the implements used for sowing
clover and alfalfa. Although alfalfa produces hay superior to timothy
' Italic numbers in parentheses refer to Literature Cited, p. 1116.
1103
1104
YEARBOOK, 1937
in yield and in percentage of protein, timothy grows well on many
soils on which alfalfa or even clover cannot be produced without a
considerable investment for lime or drainage. Timothy is very
extensively grown for hay in mixture with clover, and alfalfa can be
more readily grown on some soils not naturally suited to it if it is
sown in mixture with timothy. As a pasture grass, timothy is more
palatable to livestock than many other grasses, including redtop,
orchard grass, and Kentucky bluegrass; and the recent increased
interest in pastures has created an interest in the possibility of develop-
ing varieties of timothy especially adapted for use in pasture mixtures.
HISTORY OF TIMOTHY IMPROVEMENT
Early Efforts to Improve Timothy
According to available information, the first efforts to develop
improved strains of timothy were made in the United States. No
improved varieties were in exist-
ence at the close of the last cen-
tury, as there were of corn, oats,
wheat, and other crops. The
appreciation of the wide diver-
sity in timothy plants, which
made varietal improvement pos-
sible, and the prospect of bene-
fits to the producers of timothy
hay, both for market and for
use on the farm, if varieties were
available that would produce
larger yields of better quality
than ordinary timothy, created
incentives for the breeding pro-
grams that were undertaken at
this time by several experiment
stations and other agricultural
organizations.
Willet M. Hays, professor
of agriculture at the Univer-
sity of Minnesota (fig. 1 ), made in
1 889 a number of selections of tim-
othy plants. He had observed
the wide variation in plants of
ordinary timothy and thought
that by selecting the best from
among them it would be possible to develop varieties, sin ted for growing
in mixture with clover, that would prolong the season when timothy
could be harvested in condition to make a high grade of hay, and also
varieties capable of producing larger yields (18). No records have been
found of any earlier attempt to improve timothy in this way, although
Sinclair recorded the development of varieties of perennial ryegrass,
through selection, more than a century ago (23, vp, 212-213). Hays
discontinued his own work with timothy, but afterward, as the first
secretary of the American Breeders' Association and as Assistant
Figure 1. — Willet M. Hays, the earliest
breeder of timothy.
TIMOTHY
1105
Secretary of the United States Department of Agriculture, lie took an
active interest in the improvement of this crop.
In 1894, a few years after Hays made his first selections, A. D.
Hopkins (fig. 2), then entomologist at the West Virginia Agricultural
Experiment Station, selected a number of timothy plants at his farm
at Kanawha Station, W. Va. (14, 15, 16). He continued this work for
several years, making new selections and conducting tests of them, for
the purpose of eventually producing varieties with better quality and
higher yielding capacity than the
single unimproved strain then
available. In 1899 he distributed
plants of some of his selections
to the Department of Agriculture
and to a number of State agricul-
tural experiment stations. In
1902 he became forest entomol-
ogist and chief of the Division
of Forest Insects, Bureau of En-
tomology, Department of Agri-
culture, but continued his work
with timothy on his farms in West
Virginia . About 1 907 or 1 9C8 he
transferred additional selections
he had made to the Division of
Forage Crops of the Department.
Hopkins increased the stock of
seed of three of his selections and
introduced them as new varieties.
Seed was distributed by him and
by the Department to a number
of farmers and experiment sta-
tions. One of these varieties,
Hopkins Early, headed and
bloomed at somewhat more
nearly the same time as medium
red clover than ordinary timothy and thus was better for growing in
mixture with this clover. Stewart Mammoth, derived from a vigorous,
long-stemmed plant, was slightly later and was thought capable of
producing somewhat larger yields than ordinary timothy. The third
variety, Pasture timothy, did not differ greatly in habit of stem growth
from the ordinary strain used for hay, but its leaves tended to remain
green late, and, as its name suggests, it was thought well suited for
pastures.
Timothy Improvement by State Experiment Stations
One of the cooperators to whom A. D. Hopkins distributed plants or
seed was T. F. Hunt, of the Ohio State University. When Hunt went
to the College of Agriculture at Cornell University, Ithaca, N. Y., in
1903, he immediately began a timothy-breeding program. His
objective was the development of varieties that would give a larger
yield of superior-quality hay, and he also wished to study some of the
fundamental principles upon which a timothy-breeding program should
Figure 2. — A. D. Hopkins, who developed
the first varieties of timothy of which plants
and seed were distributed.
1106 YEARBOOK, 1937
be based. Seed was obtained from a large number of sources in the
United States and from foreign countries. Plants were grown in row
test plots, and from them many variants were obtained as the basis
for further selections. When Hunt went from Cornell University to
the University of California, the timothy-breeding investigations were
continued by H. J. Webber and his associates. At the present time,
the timothy-breeding work at Cornell is under the direction of C. II.
Myers. A number of technical studies of timothy, the variations
occurring in it, and methods of improving it have been described in
different published articles. Two varieties have been developed at
Cornell, and efforts are now being made to have seed of them intro-
duced commercially. One is somewhat earlier than ordinary timothy ;
the other is later and produces relatively large yields; both tend to
be rust-resistant.
During the period from 1911 to 1924 the Iowa Agricultural Experi-
ment Station tested about 300 timothy selections. Seed of the most
outstanding one of these was increased and distributed to Iowa
farmers, but the strain was finally lost. In Minnesota the early work
started by Hays in 1889 was later discontinued, but in 1916 work was
again resumed by others. Early work in timothy improvement was
also conducted at the Pennsylvania station, starting in 1908, but was
discontinued in 1931 . Other stations that have more recently carried
on work in timothy improvement are those of Kentucky, New Jersey,
and Wisconsin.
Timothy Improvement
by the United States Department of Agriculture
The earliest timothy-breeding work conducted by the United States
Department of Agriculture was undertaken in 1899 by F. Lamson-
Scribner, Chief, and Thomas A. Williams, Assistant Chief, of the old
Division of Agrostology, with tests of some of the selections received
from A. D. Hopkins, then at the West Virginia Agricultural Experi-
ment Station. When the Office of Forage Crops — now the Division
of Forage Crops and Diseases — of the Bureau of Plant Industry was
organized in 1903, C. V. Piper, who was in charge, became interested
in timothy improvement. From that time until 1909 a number of
new selections of leafy, vigorous timothy plants were made. Tests
were conducted at the Arlington Experiment Farm, Arlington, Va.,
of the new selections in comparison with some of Hopkins' selections,
and also in comparison with selections obtained from the New York
(Cornell) Experiment Station. The timothy-improvement program,
however, did not receive a very great amount of attention until a
decade later when the Timothy Breeding Station was established in
cooperation with the Ohio Agricultural Experiment Station. This
work was conducted first at New London, Ohio. It continued from
1909 to 1915, when the station was reestablished on a larger area of
land at North Ridgeville, Ohio. Here the work was conducted until
1935, when it was transferred to the Ohio Agricultural Experiment
Station at Wooster. The outstanding varieties developed in this
work are Huron and Marietta, described later under the heading
Improved Varieties.
TIMOTHY 1107
Timothy Improvement in Foreign Countries
Since the breeding of timothy was first undertaken in the United
States, similar work has been conducted in Canada and in several
countries in Europe.
Some of the earliest European work was done at the Plant Breeding
Institute at Svalof, Sweden. Several varieties have been developed
there, some of which arc adapted to different regions, as southern
Sweden, middle Sweden, and northern Sweden, where winter hardiness
is an essential characteristic.
Timothy-breeding investigations were undertaken at the Welsh
Plant Breeding Institute at Aberystwyth, Wales, somewhat later than
at Svalof, and have been conducted on an extensive scale. Varieties
suitable for hay production in Great Britain have been developed from
native timothy plants. Other varieties, characterized by relatively
small low-growing plants with procumbent stems that tend to become
rooted at the nodes, have been found of value in pastures in Great
Britain especially when grown in mixture with white clover. A third
type of timothy, midway between the typical hay-producing type and
the extreme pasture type, classified as "hay-pasture" timothy, also
has been developed. The methods used in timothy breeding at
Aberystwyth have been described by Jenkins (17).
Timothy-breeding investigations are also being conducted at agri-
cultural experiment stations in Scotland, Belgium, Denmark, Ger-
many, the Union of Soviet Socialist Republics, and possibly elsewhere.
OBJECTIVES IN TIMOTHY BREEDING
It is comparatively easy to develop, within a few generations, a strain
of timothy in which some single character, such as earliness or lateness,
long stems, freedom from rust, or tendency to produce large yields, is
reproduced fairly well in the plants grown from seed. To produce a
variety in which all of the desirable characteristics are combined is a
much more difficult task. Furthermore, a certain variety of timothy
may be adapted only to a more or less restricted area. For instance,
in northern Sweden the Bottnia variety is valuable because it is very
winter-hardy, but in northern Ohio it apparently has no practical
value because it produces smaller yields of hay than other varieties
that are sufficiently hardy in this latitude. Some of the late varieties
that have produced relatively large yields of high-quality hay in north-
ern Ohio are of no value in Kentucky or farther south. It is therefore
necessary to have varieties for certain regions as well as for different
uses, and this must be recognized in any well-formulated breeding
program.
The most common disease of timothy is rust. Although plants in
meadows are not often entirely destroyed by it, yet the growth of
those that are badly attacked is chocked, and the leaves dry up pre-
maturely. Some plants are more susceptible than others. Selection
for rust-resistant strains has been one of the objectives of most breed-
ers of timothy. When plants relatively free from rust have been
selected, it has been found that their progeny tend to be rust-resistant.
In an investigation conducted at MacDonald College, Quebec, Canada,
Bird (2) found that, generally speaking, the majority of improved
1108 YEARBOOK, 1937
strains of timothy tested showed marked resistance to rust. Although
strains differed greatly in their reaction to the disease, the reaction of
individual plants within strains also varied greatly. No strains were
found entirely free from the disease. Strains from Scandinavia
were generally highly susceptible to rust, yet Gloria and 0tofte, two
improved varieties, were outstanding in their resistance.
Some of the earliest public discussions of the possibility of producing
improved varieties of timothy, as of other farm crops, took place at
the meetings of the Society for the Promotion of Agricultural Science,
attended by many of the leading agricultural scientists of the last
decade of the past century and of the first decade of the present one.
A great deal of interest was aroused by Hopkins' papers on the
improvement of timothy. He described many variations, such as
early plants in condition to cut for hay about the same time as red
clover and late plants producing hay that would retain green leaves
and high quality for a longer time than ordinary timothy, and showed
the possibilities for developing distinct varieties. Here, it seemed, was
a new field of opportunity for service to agriculture. At the meeting
at Columbus, Ohio, in 1899, Hopkins said that because of the pressure
of official duties he thought he would have to give up his work with
timothy. W. J. Beal, of the Michigan Agricultural College, one of
the leading American botanists of that time, and also others pro-
tested that Hopkins should rather give up his work with insects in
order that he might be able to devote all of his time to the improve-
ment of timothy.
Present Search for Leafy Pasture Varieties
The present interest in improved pasture grasses has developed
within the last 10 years.
As already noted, pasture varieties of timothy already have been
developed and introduced in farm practice by some of the European
agricultural experiment stations or plant-breeding institutes. When
sown in fields to be used as permanent pastures, these varieties con-
tinue to form a better and more persistent turf than ordinary timothy.
At the New York Agricultural Experiment Station (Corneli),
excellent results have been obtained with Aberystwyth Pasture
timothy S. 50 when grown in association with wild white clover under
conditions of close grazing.
In general, these low-growing European types of timothy produce
very little seed in the latitude of Ohio ; for normal development they
require the longer days in spring and summer that occur farther
north. If they are used, it may be necessary to have the seed pro-
duced relatively far north, either in North America or in Europe, and
to import it into localities where it is to be sown in pastures.
Long before any of the special pasture varieties of timothy were
introduced, ordinary unimproved American timothy had been used for
pasturage. Farmers in the United States very commonly turn their
farm stock into meadows during late summer or fall, after the first
hay crop has been removed. It is also a common practice to utilize
timothy meadows from which hay crops have been harvested as all-
season pastures for 1 or more years before plowing for some other
crop.
TIMOTHY
1109
It is not unlikely that some of the improved varieties of timothy,
selected primarily for their usefulness in meadows, may also be superior
to ordinary timothy for use in pastures.
Variations a Basis for Improvement
Ordinary American timothy plants vary within quite wide limits in
season of maturity, length and degree of fineness of stems, breadth of
leaves, degree of susceptibility to rust, tendency for the leaves to
remain green as the seeds approach maturity, and in other ways.
These numerous variations and the different ways in which they are
^1
Figure 3. — A timothy plant of the pasture type grown from seed from northern Europe.
combined in different plants result in a very wide range of variants
from which selections may be made.
In Europe, as in the United States, wide variation in timothy plants
is common and some of these variants offer special opportunity to the
breeder. A form occurs in extreme northern Europe that is entirely
distinct from any found in the United States. Plants of this form
grown in the latitude of northern Ohio are characterized by short
stems, which usually grow more or less procumbent upon the surface
of the soil (fig. 3) instead of upright like the stems of ordinary Amer-
ican timothy (fig. 4). Relatively few of the stems have heads, the
florets bloom late, and the seed frequently does not form or fails to
mature. Some of the more extreme plants of this northern European
form produce no heads when they are grown as far south as northern
Ohio. .„ „ ,- ,r
Methods of Developing JNew Varieties
Timothy is generally cross-pollinated. Experiments have demon-
strated, however, that when pollen from the same plant is used
to fertilize the florets, usually a small percentage of them produce
seed.
Cross-pollination results in the occurrence of many natural hybrids
between plants of diverse types. This provides a wealth of forms
from which selections may be made, but makes the maintaining of a
new variety more difficult.
1110
YEARBOOK, 1937
The method used in the timothy-improvement work conducted by
the Department in cooperation with the Ohio Agricultural Experiment
Station is as follows:
Seed from single-plant selections is sown in a seedbed or in a small
broadcast plot. The growth of the plant of different selections is
observed and compared in
these plots, and plants are
taken from them and trans-
planted to cultivated row
plots where each individual
plant has ample space for
development. Later, from
the row plot of each strain,
one or more new selections
are made of the plants most
outstanding for the desired
qualities. When, as a re-
sult of repeated observa-
tions and tests, a selection of
sufficient merit is finally de-
veloped, the supply of seed
is increased, and it is intro-
duced under an appropriate
name as a new variel y .
Since no provision is made
during the early stages of
selection to prevent the
florets of the plant or plants
of one selection from be-
coming fertilized with the
pollen produced by plants
of other strains, the method
is known as that of selection
with open pollination. Ex-
periments conducted over
a number of years have
shown, however, that when
selection for some partic-
ular quality or character is
continued through several
generations plants may be
developed that reproduce
themselves through seed
fairly true for this character
(6).
At some other experiment
stations or plant-breeding
institutions the seed of selected plants has been produced from self-fer-
tilized florets, that is, florets fertilized with pollen from the same plant.
In this way it is possible to develop selections or varieties in which the
plants conform to a certain type more closely than if they grew from
seed produced under open pollination. In some strains of timothy
Figure 4. — A timothy plant having the relatively
long, upright stems characteristic of the American
forms.
TIMOTHY 1111
this uniformity is attained only at the cost of much loss in vigor. Our
general knowledge of the science of plant breeding indicates that
this deterioration may be overcome later by artificially cross-polli-
nating two established uniform strains and producing a hybrid in
which some of the most desirable characteristics of both parents are
combined.
At other places where timothy breeding is being conducted both
open-pollination and self-pollination are used, one method sometimes
alternating with the other from generation to generation.
When a variety of timothy is finally established and its seed is being
increased and produced on a larger scale, it is essential that indis-
criminate cross-pollination with ordinary timothy or other varieties
be avoided, or else the peculiar characteristics by which the variety is
distinguished are likely to disappear.
Improved Varieties
Though no improved timothy varieties were available at the close
of the past century, at the present time there are a number that are
as distinct from one another as varieties of corn, oats, or wheat.
Among those available commercially in the United States are Shelby,
Huron, and the recently developed Welsh pasture strain, of which
very limited quantities of seed have been imported from Great Britain
within the last 2 or 3 years.
In other countries, additional varieties, mentioned in table 1 in the
appendix, have been introduced.
The Shelby, an early-maturing variety grown in southern Indiana
for many years, apparently is the result of regional selection. William
Zoebel, of Shelby ville, Ind., producer of the variety, grew his own
timothy seed from about 1855 until the time of his death in 1892, and
his two sons continued the practice. Most of the Shelby timothy
grown on other farms in the vicinity can be traced to the Zoebel farm.
The relative time of maturity of this timothy when William Zoebel
began growing it is not known. The information available, however,
indicates that the characteristic of earliness developed gradually by
natural selection. Zoebel harvested his timothy for hay when the
earliest heads were mature. Some of the seeds from the ripe heads
shattered in the mow, or where the hay was thrown down to the
floor below. The mixed chaff and seed was swept up and the seed
was separated with the fanning mill. This process, which was repeated
year after year and continued at least up to 1930, supplies an explana-
tion of the origin of the variety that is satisfactory and may be assumed
to be correct. Little or none of the seed is shipped away from the
vicinity. Many farmers of the district who do not produce their own
seed purchase seed of Shelby timothy if it is available. If it is not
they get seed of ordinary timothy from somewhere else. Thus the
early variety and ordinary timothy have been grown on different farms
in the same locality, but Shelby timothy has retained the characteristic
of earliness.
The Huron is a late-maturing variety developed in Ohio. Plants
grown from the seed of Huron timothy are shown in figure 5 (5).
1112
YEARBOOK, 1937
In 1911 the plant from which this variety originated was found
growing along a road near "Wakeman, in north-central Ohio. It was
transplanted to the timothy breeding station at North Ridgeville
where it was grown in experimental tests. Seed was later distributed
to agricultural experiment stations in other States. In the Pacific
Northwest, in nearly all trials, the yields have been larger, the plants
have remained in condition to make a good quality of hay later in the
Figure 5. — The six plants at the right, grown from seed produced hy the original
plant of Huron timothy, are more uniform and are more vigorous and larger than
the six plants of ordinary timothy at the left.
season, and they have continued to grow for a longer time in pasture
mixtures than ordinary timothy. The Huron is now most extensively
grown in northeastern California and western Oregon, though it has
been found well-adapted to unirrigated land in northwestern Cali-
fornia and western Washington, as well as to the irrigated and moister
valleys of eastern Oregon, eastern Washington, and northern Idaho.
The use of the variety, especially in pastures in mixture with other
grasses and clovers, has been gradually expanding. It was estimated
at the Oregon Agricultural Experiment Station early in 1936 that, in
addition to its being used on several hundred acres seeded to this
variety alone, it has probably been sown in pasture mixtures on at
least 8,000 to 10,000 acres.
Another selection developed at the timothy breeding station, North
Ridgeville, Ohio, is about to be introduced under the varietal name
Marietta. In northern Ohio it is 4 or 5 days earlier and in southern
Ohio about a week earlier than ordinary timothy. Tests have
demonstrated that it yields more than ordinary timothy, especially in
the latitude of southern Ohio. It arrives at a stage of development
suitable for cutting for hay at more nearly the same time as medium
red clover or alfalfa than does ordinary timothy. The Ohio Seed
Improvement Association is planning to assist in the introduction of
Marietta timothy into farm practice in those parts of the State to
which it is well adapted.
Since the primary objective in most timothy-breeding programs is
increased hay production, most of the improved varieties developed
TIMOTHY 1113
to date are primarily hay varieties. Some of them, like that shown
in figure 6, A, are earlier than ordinary timothy. One of the charac-
teristics of an early timothy is that it is capable of producing elon-
gated stems with heads, and the florets bloom and seeds form on
them under shorter days than arc required for late varieties, such as
the one in figure 6, B. For this reason, early varieties can produce
a hay crop in the South, where the days during spring and summer
1
A
i
3
Figure 6. — A, A plot of early timothy, full-headed and beginning to bloom; li, a plot
of late timothy, with stems grown to only a part of their full length. Photographed at
North Kidgeville, Ohio, June 20, 1933.
are too short for the proper development of late varieties. Trials in
southern Ohio and at the Kentucky Agricultural Experiment Station
have demonstrated the correctness of the theory that near the south-
ern border of the timothy-producing area in the United States early
varieties produce materially larger yields of hay than late varieties.
Distribution of Improved Varieties
In Sweden certain organizations formed for the purpose of introduc-
ing the seed of new and improved varieties of all kinds of farm crops
have been instrumental in having some of the new varieties of timothy
grown. No organized effort of this kind has yet been made on a large
scale in the United States.
At Cornell University and in Ohio seed has been distributed to
farmers who expect to harvest a seed crop. The same method is
used in Ontario, Canada. In Quebec the seed is sent to the Provincial
seed farm and from there to Provincial seed centers. In Great Britain
improved strains are now being grown on a commercial scale by seeds-
men. In Sweden all seed is sold and distributed by the Svalof Seed
Co., which has a monopoly on all varieties produced by the Swedish
Seed Association.
The increased cost of seed must always be taken into consideration
in the establishment of new crop varieties. The seed of improved
varieties of timothy necessarily sells at a somewhat higher price than
that of ordinary unimproved timothy. This is because, the seed
138904°— 37 71 ++
1114 YEARBOOK, 1937
grower must use extra care not to have any ordinary timothy plants
growing in mixture where seed of the improved variety is being
produced. Further, if the seed is certified, the cost of inspecting the
meadow must be added. However, the total quantity of timothy
seed required for establishing 1 acre of meadow is so small that the
slight additional cost for the improved seed should be no objection if
the varieties are distinctly superior.
Since relatively long days are required for their development (7),
it appears probable that the usefulness of late varieties of timothy
will be restricted to latitudes no farther south than the northern part
of Ohio (8). When grown under suitable conditions, it has been found
that the better late varieties produce somewhat more hay than
ordinary timothy, though usually these increases in yield per acre
do not exceed a few hundred pounds. The leaves on the best late
selections remain green for a longer time than those of ordinary
timothy, and consequently the protein content and quality of the
hay remain at a relatively high level for a longer time. On farms
in the northern part of the United States, where relatively large
acreages of clear timothy hay are harvested and where there is
difficulty, because of unfavorable weather conditions or the pressure
of other farm work, in harvesting ordinary timothy early enough
to produce hay of a high quality, late varieties would have certain
advantages.
Timothy is now being grown in mixture with alfalfa in an increasing
area each year (1). This mixture should be harvested early, before
ordinary timothy has begun to bloom. It is apparent, therefore,
that an earfy variety of timothy, that would be in bloom when the
crop should be harvested, is most suitable for such a mixture and
should be supplied by the timothy breeder.
No varieties of timothy that are primarily pasture types have yet
been produced in the United States. The Welsh pasture variety,
seed of which is now available to a limited extent, is characterized
by its short, low-growing stems, and it would produce much smaller
yields of hay than any of the hay types. There has been so little
experience in this country with the European pasture varieties,
oven experimentally, that it is not yet clear just how useful they
may be.
As indicated in the preceding paragraphs, the principal objectives
in the improvement of timothy are the development of rust-resistant
varieties; early varieties suited to the southern part of the timothy-
growing area; late varieties for the North, for use where timothy
meadows are maintained for 2 or more years; varieties adapted for
hay production when grown in mixture with clover or alfalfa; and
varieties for use in pastures.
Technical Research 2
When T. F. Hunt began the timothy-breeding investigations at
Cornell University in 1903, seed was procured not only from many
different places in the United States and Europe but also from other
countries. The plants grown from these lots of seed revealed the
' This section is written primarily for students and others professionally interested in breeding or genetics.
TIMOTHY 1115
existence of a very wide range of types (26). Some of the strains at
Cornell were used by Clark (8) in a technical study of variation and
correlation in timothy. Smith and Myers (24) have recently pub-
lished the results of a biometrical analysis of yield trials.
Investigations at MacDonald College on the rust resistance of
improved strains have been previously referred to.
Gregor and Sansome (10) found that the low-growing forms of
timothy plants with more or less procumbent stems, which occur in
Great Britain, have 14 chromosomes (2n), whereas the plants with
longer, more nearly upright stems have 42 chromosomes (Cm). Plants
of the latter type, which occur both in Europe and in North America,
wore designated by these authors as the "American" and the
low-growing forms as "British Wild" type. Gregor at first found
these two types are intersterile (.9), but according to a recent report
(18) they later were able to produce artificial P, hybrids between
them.
Sethi, in a study conducted in India of Phleum, Phalaris, and
Festwca, found seven as the basic chromosome number in each genus
(22). In Phleum, while different morphological types interbreed
quite readily provided they have the same number of chromo-
somes, diploid and hexaploid types can be crossed only with great
difficulty.
At the Plant Breeding Station at Svalof, Sweden, Muentzing (19)
observed and studied spontaneous hybrids between Phleum pratense
and P. alpinum (An). Some of these hybrids were approximately
pcntaploid.
The extent to which timothy florets produce seeds under conditions
of self-pollination has been studied by Wittc (27), Valle (28), and other
European investigators. In general, it has been found that when
they are self-pollinated the average percentage of florets producing
seeds is very much less than under natural conditions that permit
cross-pollination.
A series of genetic studies of timothy has been conducted at the
Minnesota Agricultural Experiment Station. Hayes and Barker (11)
found that there is a considerable amount of variation in the extent
to which timothy may be self-pollinated. Some plants are highly
self-sterile, others are highly self-fertile. Clarke found that although
a few of the selfed lines wrere markedly reduced in vigor- the majority
compared favorably in yielding ability with the open -pollinated com-
mercial strains (4). He observed that when timothy seeds are
produced by self-fertilized florets for a few consecutive generations
the plants grown from these seeds are more uniform than plants
grown from seed from open-pollinated florets.
Hayes and Clarke, in an investigation conducted at the Minnesota
Experiment Station (12), found that selection in self-fertilized lines is
a logical means of freeing the lines of undesirable recessive characters
and of obtaining vigorous lines that excel in such important characters
as yielding ability and disease resistance. On the other hand, it has
also been found elsewhere (6) that when selection for any particular
type is continued, even under natural conditions favorable for open
pollination, the plants of many strains representing several generations
of selection show a high degree of uniformity.
1116 YEARBOOK, 1937
LITERATURE CITED
(1) Bachtell, M. A., Allen, II., and Monroe, C. P.
1934. ALFALFA-TIMOTHY HAY FOB I'M DAIRY FARM . . . Ohio Agr. Expt.
Sta. Bull. 538, 41 pp., illus.
(2) Bird, J. N.
1934. INFLUENCE OF RUST INJURY OX THE VIGOUR AND YIELD OF TIMOTHY.
Sci. Agr. 14: S50-559, illus.
(3) Clark, C. F.
1910. VARIATION AND CORRELATION IN TIMOTHY (PHLEUM PRATENSE L.).
N. Y. (Cornell) Agr. Expt. Sta. Bull 279, pp. [3011-350, illus.
(4) Clarke, S. E.
1927. self-fertilization of timothy. Sci. Agr. 7: 409-439.
(5) Evans, M. W.
1933. huron timothy. U. S. Dcpt. Agr. Leaflet 99, 5 pp., illus.
(6)
1930. selection of open-pollinated timothy. Jour. Amer. Soc. Agron.
28: 389-394, illus.
(7) and Allard, II. A.
1934. relation of length of day to the growth of tcmothy. Jour.
Agr. Research 48: 571-586, illus.
(8) Allard, II. A., and McConkby, O.
1935. time of heading and flowering of early, medium, and late
timothy plants at different latitudes. Sci. Agr. 15:
573-579.
(9) Gregor, J. W.
1931. experimental delimitation of species. New Phvtol. 30:
204-217, illus.
(10) and Sansome, F. W.
1930. experiments on the genetics of wild populations. II. PHLEUM
PRATENSE L. AND THE HYBRID P. PRATENSE L. X P. ALPINUM L.
Jour. Genetics 22: [3731-387, illus.
(11) Hayes, II. K., and Barker, H. D.
1922. the effects of self-fertilization in timothy. Jour. Amer.
Soc. Agron. 14: 289-293.
(12) and Clarke, S. E.
1925. selection in self-fertilized lines as a means of improving
timothy. Sci. Agr. 5: 313-317, illus.
(13) Hays, W. M.
1892. improvement of timothy. Minn. Agr. Expt. Sta. Bull. 20-
[451-40.
(14) Hopkins, A. D.
1895. some observations on varieties of timothy. Soc. Promotion
Agr. Sci. Proc. 16: 29-33, illus.
(15)
1899. PROGRESS IN THE STUDY' AND IMPROVEMENTS OF VARIETIES OF
timothy. W. Va. Agr. Expt. Sta. Kept. 12: 33.
(10)
1906. breeding timothy. Amer. Breeders Assoc. Proc. 2: 95-99.
(17) Jenkins, T. J.
1931. the method and technique of selection, breeding and strain-
building in grasses. Imp. Bur. Plant Genetics, Herbage
Plants, Bull. 3: 5-34, illus.
(18) Jones, R. P.
1936. the Swedish seed associatjon. Herbage Rev. 4: 32-34.
(19) Muentzing, A.
1935. CYTOGENETIC STUDIES ON HYBRIDS BETWEEN TWO PHLEUM SPECIES.
Hereditas 20: 103-136, illus.
(20) Piper, C. V.
1914. FORAGE PLANTS AND THEIR CULTURE. 618 pp., illllS. New York.
(21) ■ and Botrr, K. S.
1915. THE EARLY" AGRICULTURAL HISTORY OF TIMOTHY. Jour. Amer. SoC
Agron. 7: 1-14.
TIMOTHY 1117
(22) Sethi, B. L.
1932. A STUDY OF SOME SPECIES AND TYPES OF l'HLEDM, PHALARIS AND
FESTCCA WITH REGARD TO CHROMOSOME XUMBEBS AND BREEDING
properties. Indian pSci. Cong. Calcutta Proc. 19: 312-313.
[Abstract in Expt. Sta. Rec. 70: 757.]
(23) Sinclair, G.
1824. hortus gramineus wobtjrnensis : ; . 438 pp., illus. London.
(24) Smith, H. F., and Myers, C. H.
1934. A BIOMETRICAL ANALYSIS OF YIELD TRIALS WITH TIMOTHY VARIETIES
using rod rows. Jour. Amer. Soc. Agron. 26: 117-128.
(25) Valle, O.
1931. UNTERSUCHUNGEN UBER DIE 8ELBSTSTERILITA.T UND SELBSTFER-
TILITA.T DES TIMOTHES (PHLEUM PRATENSE L.) UND tTBER DIE
EINWIRKUNG DER SELBSTBEFRUCHTUNG AUF DIE NACIIKOMMEN-
SCHAFT EINE ZUCHTUNGSMETHODISCHE STUDIE. SuODiert Maata-
lonst. Leuran Julk. (Acta Agralia Fennica) No. 24, 261 pp., illus.
(26) Webber, H. J., with the collaboration of Hunt, T. F., Gilmore, J. W.,
Clark, C. F., and Fraser, S.
1912. THE production of new and improved varieties of timothy.
N. Y. (Cornell) Agr. Expt. Sta. Bull. 313, pp. 338-392, illus.
(27) Witte, H.
1915. OM timoteje.v, dess historia, odling ocii formrikedom samt om
FORADLINGSARBETEXA MED DETTA VALLGRAS PA. SVALOF. SverigeS
Utsadesfor. Tidskr. 25: 23-44, 143-191, 199-230, illus. [In Swed-
ish. German summary, pp. 222-230.]
APPENDIX
Table 1. — Introduced varieties of timothy
Location and institution
United States:
Cornell University,
New York Agricul-
tural Experiment
Station.
Ohio Agricultural Ex-
periment Station co-
operating with U. iS.
Department of Ag-
riculture.
Canada:
Central Experimental
Farm, Ottawa.
( .'ollcge of A griculture,
Alberta.
Ontario Agricultural
College, Guelph.
MacDonald College,
Quebec.
Great Britain:
Aberystwyth, Wales.
Breeder
Variety and year
introduced
C. H. Myers, W. I.
Fisher.
do
Morgan W. Evans.
.do..
O. Malte, R. I. Ham-
ilton, G. P. Mc-
Kostie.
F. K. Fryer
O. M. McConkey..
....do.
do
J. Norman Bird..
do
T. J. Jenkins..
.do.
.do-
Cornell 1777, 1922.—
Cornell 4059, 1922
Huron, 1933
Marietta, 1930
Boon, 1923 _.
Swallow, 1920
O. A. C. No. 1, hav
type, 1934.
O. A. C. No. 1, inter-
mediate type, 1933.
O. A. C. No. 1, pas-
ture type, 1933.
Montcalm, 1932
Milton, 1930
S. 48
S. SO
S. 51
Characteristics
Good yields; rust-resist-
ant; medium early.
Good yields; late
Late, leafy, rust -resist-
ant.
Medium early, leaves
remain green well;
rust-resistant.
Heavy - yielding bay
type; rust-resistant.
Leafy hay type
Leafy, rust -resistant
Leafy, late
Persistent bottom grass.
Rust-resistant, superior
yields.
Rust-resistant, good
yields, early.
Persists under grazing;
leafy; rust-resistant;
hexaploid.
Exceptionally persistent
under grazing; creep-
ing; diploid.
Very leafy hay type;
winter-green; rust-re-
sistant; hexaploid.
Breeding methods
Selection of outstanding
plant followed by self-
ing.
— -do....
Selection-
Selected through 3 gener-
ations with open pol-
lination.
Controlled mass selec-
tion and suitable tests
to evaluate strains.
Maternal line selection
with open-pollination
in isolated plots.
Inbreeding and selec-
tion.
do
-do.
Combination of selfed
lines.
Selected plants allowed
to outcross with other
selected plants of same
type.
Selection and hybridiza-
tion intermingled.
-do.
Parental material
Commercial stocks..
.do-
Plant growing along
roadside in northern
Ohio.
Plant growing in an old
meadow in northern
Ohio.
Wild plants from Al-
berta, Canada.
Svalflf 523 from Sweden .
Danish material
Swedish genotypes
Russian genotypes
Svalof Nos. 237-A and
523, Sweden.
Minnesota Nos. 79 and
81, Svalof 523, Cor-
nell 1070, F. C. 12408
(Ohio).
Selected British indige-
nous plants.
From very old British
pasture.
Selected British plants..
Estimated acreage,
1930
03
Limited.
Do.
About 8,000 to 10,000
acres for hay and
pasture.
About 50 acres.
About 300 acres for hay
and seed.
Quite extensive in
northern Alberta.
1 acre.
Increase block.
Do.
1 0 acres.
About 47 acres for seed
production.
About 18 acres for seed
production.
About 01 acres for seed
production.
to
to
o
©
-J
Craig's House, Cor-
storphme, Edin-
burgh, Scotland.
Sweden:
Svalof.
Lulca
Landskrova..
Norrkoping.
J. W. Grcgor
H. Wittc
S. O. Berg
George Nilsson
A. Uhlander...
15. Kajanus
Algot Holmbcrg &
Son.
CblDl
Gloria, 1920.
Wciball Kampe II,
1933.
Bore, 1929
Bottnia, 1929
Weiball Kampe 1,
1922.
Svea
Diploid; stems ascend-
ing about 2 feet; per-
sistent bottom grass
for pastures.
High yield; rust-resist-
ant,
.—do
Selection and hybridiza-
tion.
I
Selection.
do.....
Wild plants from east
Scotland.
Swedish wild plants..
do
Winter hardy . ..! do ;. ...do.
do 1 do do.
Iligh yield, rust-resist- ! do „_;
ant. i
i'A acres for seed pro-
duction.
Large.
Do.
Considerable.
Do.
Large.
o
Table 2. — Timothy-breeding projects
Location and institution
United States:
Agricultural Experiment Sta-
tion, Ames, Iowa.
Agricultural Experiment Sta-
tion, Lexington, Kyi
Agricultural Experiment Sta-
tion, St. Paul, Minn.
Agricultural Experiment Sta-
tion, New Brunswick, N.J.
Personnel
Date
New York (Cornell) Agricul-
tural Experiment Station,
Ithaca.
Ohio: Agricultural Experiment
Station and L". R. .Depart-
ment of Agriculture coop-
erating:
New London
North Ridgeville.-
Wooster ___
Agricultural Experiment Sta-
tion, State College, Pa.
Arlington Experiment Farm,
U. S. Department of Agri-
culture, Arlington, Va.
Agricultural Experiment Sta-
tion, Kanawha Station and
Morgantowu, W. Va.
Agricultural Experiment Sta-
tion, Madison, Wis.
Present
1911-21 i None..
193.5-
1889-92
HUG- I
K«l-
191. 1-35
1935-
1908-31
1899-J90S
E. N. Fergus.
H. K. Haves, I. J. Johnson, C. W
Doxtator, n. K. Schultz, W. M,
Myers.
H. B Sprague, II. E. Blascr, M. E
Paddick.
C. H. Myers, W. I. Fisher....
M. W. Evans..
do.
do.
None.,
! W. M. Hays, H. D. Barker, Sid-
ney Clarke, F. It. Immer.
! E. E. Evaul, N. F. Farris, W. O.
I Colby, N. C. Curtis.
T. F. Hunt, J. \V. Gilmore, Sam-
uel Fraser, H. J. Webber, C F.
Clark, II. F. Smith.
C. V. Piper, R. A. Oakley.. .
_do_
C. F. Noll.
Nature of work to date
F. Lamson-Scribner, T. A. Wil- |
liams, C. V. Piper.
Suggested work for future
Mass selection.
Selection.. Development of pasture types.
Photoperiodism in relation to
varieties.
Determining the nature of
self-fertility; effects of in-
breeding; effects of crossing.
Development of leafy type for
pasture; inheritance studies;
extent of natural cross-fertili-
zation.
Development of pasture types;
cause of sterility.
Selection, hybridizing, cy-
tology, comparative test-
ing.
Selection
Line selection.
Selection.
...do
...do
Selection, inbreeding .
Selections.
Studies of relation of length of
day and of latitude to the
growth of early, medium, and
late timothy and the eflects
of outcrossing with improved
straius of similar types.
Do.
Do.
Development of early strains
for growing with clover, and
late strains to prolong the
harvesting season.
1891-1908 do | A. D. Hopkins | do.
103B- 0. S. Aamodt, F. Tinney, A. H.
I Ahlgren.
-j Selection, cytology, develop- j Fertility study of different
I ment, of hay and pasture ■ strains.
I varieties. I
to
-]
Canada:
Central Experimental Farm,
Ottawa.
College of Agriculture, Ed-
monton.
College of Agriculture, Guelph.
MacDonald College, Quebec_
Wales:
Plant Breeding Station,
Aberystwyth.
Scotland:
Craig's House, Corstorphine,
Edinburgh.
Belgium:
Plant Breeding Station,
Ghent.
Sweden:
Swedish Seed Association,
Svalof.
Weibullsholm Plant Breeding
Station, Landskrona.
Otto J. Olson & Son (seeds-
men), Hammenhog
1912- E. McVicar.
1920-
1904-
1918- ■ J. K. Fryer
1923- i O. McConkey..
J.N. Bird-.
T. J. Jenkins..
O. Malta, R. I. Hamilton, G. P.
McHostie.
Mass selection for hay and
pasture varieties.
Selection and selfing
Genetics, cytology, mass
selection, and inbreeding.
L. S. Klinck, L. A. Waitzingor,
G. P. McBostie, A. McTaggart.
la
Selection with open-pollina-
tion with selected plants
of a similar type.
Selection and hybridization;
technique and rust-resist-
ance; cytology.
Development of pasture-hay
types with disease and cold-
resistance and high seed-
yielding capacity.
Study of reduced fertility from
selling; effects of crossing;
genetic studies.
Development of leafy rust-
resistant varieties compati-
ble in mixtures; collection of
breeding material from north-
ern latitudes.
The development of strains
producing more aftermath.
J. W. Gregor j i Selection and hybridization
B. Govaort.
G. Niisson-Lcissner, N. Sylven,
A. Miintzing, F. Nilsson, G.
Nilsson, J. E. Siden, F. Naos-
man.
A. Akerbcrg.
E. Nilsson.
H. Wltte, A. Uhlander.
B. Kajanus, O. Berg.
Selection-
Selection, inbreeding, and
subsequent crossing; in-
heritance.
Genetics of various types, to
determine minimum number
of interrelated plants that can
be used in strain building
without loss of vigor.
Physiology of breeding mate-
rial, and development of trial
technique for evaluation of
characters other than yield.
Development of winter-hardy.
high-yielding types resistant
to lodging; creeping types for
pasture; types with high
nitrogen content and superior
ability to utilize nitrogenous
manure.
ALFALFA IMPROVEMENT
H. M. TYSDAL, Associate Agronomist,
H. L. WESTOVER, Senior Agronomist,
Division of Forage Crops and Diseases,
Bureau of Plant Industry1
A.LFALFA means "best fodder" in Arabic, the language from which
the crop received its name. Botanically it is known as_ Medicago
sativa L. In England and most other European countries it is called
lucerne, perhaps after Lake Lucerne and Lucerne Canton, in Switzer-
land, where alfalfa was grown at an early date, though some believe
the name was derived from the Spanish or the French.
Alfalfa is a member of that large and important group of plants
called the legume or pea family, characterized by ability to provide a
home for useful bacteria that take nitrogen from the air and store it in
a form available to plants, thereby enriching the soil. The home for
nitrifying bacteria is on the roots in what are known as nodules, which
look like small detachable lumps or knots. The soil-improving value
of legumes, combined with their forage values, makes them one of the
great economic plant families.
In 1929 alfalfa hay was produced on approximately 35 million acres
throughout the world, according to Klinkowski (19).2 In addition, a
proportionately large acreage was devoted to alfalfa-seed production
in those regions where climatic and soil conditions are conducive to seed
i The authors gratefully acknowledge the assistance of N". F. Petersen, who prcpiired t. lies key on the com-
mon species of Medicago. ■
! Italic numbers in parentheses refer to Literature Ciled, p. 1147.
THE most serious threat to alfalfa growing in the United Slates
is the insidious disease, bacterial wilt, which kills stands of sus-
ceptible alfalfa in 2 to 4 years. In the large area where this disease
is present — and it is spreading to other areas — it annually destroys
hundreds of thousands of acres of alfalfa, with aggregate losses
equivalent to those that would be experienced by farmers as a result
of flood, drought, or any other major disaster. If varieties or strains
could be developed that were sufficiently resistant to maintain stands
even 2 years longer, these farmers would be saved many millions of
dollars. This is one of the problems on which alfalfa breeders are
now working, and promising progress has been made.
1122
ALFALFA
1123
setting and maturity. Argentina reported 14 million acres of alfalfa
hay in 1929, the United States nearly 12 million acres (fig. 1), and
France 3 million acres. Other countries reported smaller acreages,
but the crop was widely distributed. Since 1929 the aggregate acre-
age of alfalfa is believed to have extended, but there are no available
figures to support this belief .
There are many types of alfalfa, and they display wide differences
in their adaptation to environmental changes from the Mexican to the
ALFALFA CUT FOR HAY
Acreage 19'29
UNITED STATESTOTAL
11,516.000 ACRES
Figure 1. — Distribution of alfalfa production in the United Slates in 1929. Approxi-
mately 1 J, 500,000 acres were cut for Iiay in ilia I year.
Canadian borders and from the arid West to the humid East. They
differ not only with respect to soil and climate, but also with respect
to their resistance to disease and insect injury.
These differences, long recognized by alfalfa growers and research
workers, are now being utilized by plant breeders as the basis of im-
provement of the crop, and the results of breeding work to date indi-
cate that superior strains can be developed that will make possible an
even greater use of alfalfa on the farms of America.
EARLY HISTORY
The best authorities agree that the original home of alfalfa was in
•southwestern Asia, from Mesopotamia northward across Persia and
Turkistan to Siberia. De Candolle (4) states that it has been found
wild, with every appearance of being an indigenous plant, in several
provinces of Anatolia, to the south of the Caucasus, in several parts of
Persia, in Afghanistan, in Baluchistan, and in Kashmir. More re-
cently, Department of Agriculture explorers have found many so-
called "wild alfalfas" in the region of Turkistan, so there can be no
doubt that alfalfa got its start in this general region.
1124 YEARBOOK, 1937
Alfalfa was probably planted in this region by half-civilized man
ages before any history was written. The earliest records indicate
that by that time man had discovered the superior feeding value and
soil-building properties of alfalfa. One of the earliest Roman agri-
cultural writers, Columella, stated in Do He Rustica, written about
56 A. p., that all emaciated cattle whatsoever grow fat on it and that
it fertilizes the land.
_ Alfalfa was thus developed in dry regions and was usually found in
river valleys with soils rich in lime and of alkaline reaction. Wing
(32) has suggested that the grass eaten by Nebuchadnezzar when he
was driven into the fields was none other than alfalfa growing in the
fertile valley of the Euphrates River near Babylon. The earliest
records alluding to alfalfa were discovered in Babylonian text written
in 700 B. C. In this reference alfalfa is listed under its Persian name,
aspasti, by the gardener of the Babylonian King, Mardukbalidin,
which shows that alfalfa was known in the palace grounds of that day.
From this point on the story of alfalfa becomes history. Pliny and
Strabo, both early Roman writers, record that when the Modes and
Persians invaded Greece in 490 B. C., they introduced alfalfa into that
country for the sustenance of their chariot horses, camels, and domestic
animals. The plant was named medic, to denote its Median origin,
and it has retained this root in the present botanical name, Medicago.
This is believed to be the first introduction of alfalfa into Europe.
From there it spread to Italy and during the next centuries to other
European _ countries, including Spain. Thus the queen of forage
plants, as it has been called, followed the path of historic civilizations
and conquering armies from East to West.
Introduction into the Americas
The first introduction of alfalfa into the Americas was through the
Spanish explorers. When Cortez and Pizarro had completed their
conquest, the natives had alfalfa in lieu of their gold . This was at the
beginning of the sixteenth century, and alfalfa soon became distributed,
over Peru and Chile. It is probable, though not certain, that some
of the Catholic missionaries brought alfalfa from Mexico into southern
California, New Mexico, and Arizona. Be that as it may, there was
no decided spread of alfalfa growing in North America at this time.
The English, French, and Germans introduced alfalfa into the
colonies of the Atlantic seaboard under the name of lucerne. There
was some success in growing it in Virginia, North Carolina, Pennsyl-
vania, and New York, but there were also some disappointments, due,
no doubt, to a general lack of well-drained limestone soils and also
to lack of knowledge of the necessity of inoculating for nitrogen-gather-
ing bacteria, which, when present, grow on the roots of legumes.
General Washington tried alfalfa at Mount Vernon with, enough suc-
cess to warrant planting a field of it in 1794. Thomas Jefferson, ac-
cording to Spurrier, took considerable pride in his lucerne field, which
was in production prior to 1793.
To trace the further introduction of alfalfa into the United States,
it is necessary to return to the west coast, where in the gold rush days
of the 1850's many prospectors came via the all-water route around,
the Horn to California. Some of them stopped at Chilean ports en
ALFALFA 1125
route, and, curious as to how this new plant would grow in the new
country, took some seed with them. One of the first growers of
alfalfa in California, according to the account related by E. J. Wickson
to Wing, was W. A. Cameron, of Marysville, in the Sacramento
Valley. He produced alfalfa in 1851, and his seed came from Chile.
From the beginning alfalfa produced remarkably good crops in the
fertile irrigated valleys of California, and it is not strange that its
gradual spread was across the country from the West rather than from
the East, because, although it had been grown continuously in New
York for over a century, it received its main impetus from the success
it had attained in the West. From California it was soon taken to
Utah, where the Mormons found it extremely satisfactory. It was
then introduced into Colorado, Kansas, and Nebraska. According to
the 1916 report of tbe Kansas State Board of Agriculture (8, p. 11),
one of the first Successful growers of alfalfa in Kansas was Charles J.
Grosse, of Marion, who received his seed in 1868 from the Trumble-
Seed House on Sansom Street, San Francisco, Calif. In the 1890's
alfalfa had become an important crop in Kansas and spread into
Nebraska, where it was also successful. By 1900 it had crossed the
Missouri River and become important on the well-drained and alluvial
soils of Iowa and Missouri. Then it spread across the Mississippi
into Illinois. Wing had previously carried the crop from a ranch in
eastern Utah to Champaign County, Ohio, where he established one
of the first really successful alfalfa projects in the State.
Considering the historical background of alfalfa production in this
country, it is probably safe to assume that the so-called Common
alfalfa now being extensively grown originated from the early intro-
ductions of Chilean alfalfa. It is also evident that through the years
the crop has been remarkably changed by natural regional selection.
As indicated by Westover (30), strains developed that have the
ability to become relatively dormant in the fall and resist cold, as is
the case with Northern Common. Other strains, such as the Com-
mon alfalfa found in the South, grow rapidly late in the fall; in other
words, they do not respond so greatly to the shortening day length.
Hybridization no doubt has also been a factor in this adaptation, but
segregation by survival has been predominant.
Grimm Alfalfa
At about the time alfalfa was being introduced into California,
another circumstance was paving the way for the growing of alfalfa in
northern climates. In 1857 Wendelin Grimm brought his family
from the Grand Duchy of Baden, Germany, to Carver County, Minn.
(figs. 2 and 3). In the spring of 1858 he sowed 15 or 20 pounds of
alfalfa seed brought from his native land. This proved to be the
origin of what was later called Grimm alfalfa — the first alfalfa grown
in this country that had sufficient hardiness to withstand the cold
winters of the North. Many attempts had been made to grow the
nonhardy alfalfas in Northern States, but this invariably resulted in
winter-killing. The advent of Grimm alfalfa greatly increased the
acreage importance of the crop.
There can be no doubt that the wide distribution of Grimm today
is due to the comparative testing of experiment stations, where its
1126
YEARBOOK, 1937
superiority was proved and given publicity. This alfalfa was grown
in practical obscurity for almost 50 years before it came to the atten-
tion of experiment station officials, after which it was soon widely
known. It would be hard to find a better example of the leadership
afforded by experiment stations in agricultural work.
The discovery — and it can well be called a discovery, because very
little was known regarding
the adaptation of alfalfa in
this early period — that cer-
tain strains were not adapt-
ed to certain regions while
others thrived there, was an
important one. No longer
could a prospective grower
just ask for alfalfa seed — he
had to be sure of the kind
of alfalfa seed he was get-
ting. Some confusion thus
arose because it was impos-
sible to tell one variety
from another by the seed,
but fortunately this diffi-
culty has been overcome by
certification and verifica-
tion services made available
by State and Federal in-
stitutions.
Early Breeding Work
Without doubt, natural
selection in alfalfa, helped
here and there by the will-
ing hand of man, has taken
place for many generations.
This is evident from a com-
parison of our vigorous-
growing, sturdy cultivated
alfalfas with the prostrate,
slow-growing wild species
picked up by plant explor-
ers. But it must also be
admitted that no plant of
such economic value and
an tiquity shows solittle evi-
dence o f delibera te breeding.
Only two examples, both cited by Brand (2), 15)07, are needed to show
what apparently had been accomplished by natural selection, helped
along by man. Peruvian alfalfa, which is now grown to a consider-
able extent in the Southern States, has a very low zero point, that is,
ability to grow at a low temperature, but is not at all winter-hardy in
northern latitudes. This, Brand suggested, has been due to many
centuries of growing in warm climates. On the other hand, it is
Figure 2. — Mr. and .Mrs. \\ endelin Griini
Chaska, Carver County, Minn. In 1858 Mr.
Grimm planted 15 or 20 pounds of alfalfa seed he
brought with hiiu from Germany the previous
year. This was the beginning of the present
widely grown and popular Grimm alfalfa variety.
(Courtesy of A. C. Amy, Minnesota Agricultural
Exj»eriment Station.)
i
ALFALFA
1127
rather surprising that the original home of Grimm alfalfa in Germany
has minimum temperatures less severe than those observed at Albu-
querque, N. Mex. From all available records it is clear that the bulk
of the original Grimm seed was not sufficiently winter-hardy for
Minnesota conditions. Yet by saving seed from the plants that
survived each successive winter, generation after generation, the
persistent German immigrant, Wendelin Grimm, showed what could
be accomplished in the
way of acclimatization
or adaptation of alfalfa
in Minnesota.
In a report of the
committee for breed-
ing forage crops, made
by Piper {24) in 1909,
a very good picture is
given of the alfalfa-
breeding program in
the entire United
States at that time.
"It must be bome in
mind", the report
states, "that alfalfa
breeding is a very re-
cent development of
p 1 a n t improvement,
apparently no work
having been conducted
along this line prev-
ious to 1903." At the
time of the report 11
workers were directly
interested in alfalfa im-
provement: J. M. West-
gate, C. J. Brand, G.
W. Oliver, and A. C.
Dillman, all of the
United States Depart-
ment of Agriculture;
G. F. Freeman, of
Kansas; W. H. Olin
and P. K. Blinn, of Colorado; F. A
Figure 3. — Monument creeled in honor of Wendelin
Grimm, who greatly benefited northern agriculture by
originating the hardy variety that bears his name.
(Courtesy of A. C. Amy, Minnesota Agricultural
Experiment Station.)
Spragg, of Michigan; E. G.
Montgomery, of Nebraska; W. A. Wheeler, of New York; and L. R.
Waldron, of North Dakota.
Practically all these workers had a well-developed program, chiefly
involving mass selection. Only Oliver, Westgate, and Brand report
hybridization of varieties or species, but without definite results.
Two rather distinct methods of selection were followed. Spragg,
Dillman, and others selected mother plants without control of the
male parent except cutting back adjacent undesirable material at the
time of blooming. Olin, Oliver, Brand, and others self-fertilized the
selected plants, using wire cages or bagging. This group thoroughly
1128 YEARBOOK, 1937
understood the possibility of contamination by cross-fertilization, but
apparently they did not fully realize that an individual selected plant
might not necessarily — probably would not — pass on all its good
characteristics to the next generation. Thus too much effort was
often spent in picking out the best plant in the entire nursery, only
to find when seed was obtained that the daughter plants were not at
all like the mother plant. It must be added, however, that even at
this early date many breeders knew the value of the progeny test
and used it to determine which was the best parental material.
The workers of this period had a considerable number of strains to
use for foundation stock. The State experiment stations had access
to the collection of the Department of Agriculture, which included
introductions from all important alfalfa-growing regions as well as
material from more out-of-the-way parts of the world. The major vari-
eties used were Grimm, Common, and Turkistan. There were also
introductions of other species, chiefly Medicago faleata L., and a few
species crosses were made, but apparently nothing came of them.
Among the more important characters selected for at this date were
frost resistance, forage productivity, drought resistance, desirable
habit of growth, seed productivity, leanness, and resistance to leaf
spot (Pseudopeziza medicagims (Lib.) Sacc). It is interesting to
note, however, that only one worker mentions breeding for disease
resistance, and then it is not given much prominence. In reply to
the question "What are the most serious difficulties you have found
in breeding alfalfa?", made in Piper's survey of 1909, the following
answers were received:
(1) Difficulty of keeping strains pure, both during breeding and for increase.
(2) Maintaining a large nursery several seasons to await winter-killing or
drought to eliminate undesirable individuals.
(3) Securing seed.
(4) Length of time required to determine the value of any given plant, some
suggesting 3 years as the minimum.
Results of Early Improvement Work
The early work can bo said to have begun about 1903 and ended
about 1915. During this period there was considerable interest in
the improvement of alfalfa, one outstanding character sought being
winter-hardiness (fig. 4). A group of superior varieties and strains,
together with the date they originated, is listed in the appendix, and
it may be noted that several of these came into prominence during
this early period, notably Grimm, Baltic, Cossack, Ontario Variegated,
and Ladak. Figure 5 shows the origin of Ladak and the nursery from
which it was selected at the United States Department of Agriculture
Experiment Station, Redfield, S. Dak. All of these varieties have
superior characteristics, such as cold resistance and adaptation for
special conditions. They are all still considered standard varieties.
Introduction and selection played a part in their development.
It must be added, however, that many an alfalfa selection was
"born to blush unseen" during this period. Some very promising
selections made in various nurseries never got any further. Wheeler's
Grimm No. 19A was increased to the extent of 100 acres, then turned
over to farmers and its identity lost. No doubt the worth-while
ALFALFA
1129
characteristics in this strain have through the years gradually made
themselves felt in other strains with which it crossed. Thus the work
put into such selections has not been entirely lost.
Nevertheless, the early work did not reach full fruition, for several
reasons, among them the World War, which focused attention on the
food crops to the detriment of the feed crops, and the widespread
Figure 4. — A demonstration of llie difference in cold resistance of different alfalfas.
Nebraska-grown Common alfalfa at left and Peruvian alfalfa at right, seeded May 16,
1922. Both varieties seemed equally good during 1923 and 1924, but the Peruvian
winter-killed almost completely in the winter of 1924-25, while the Nebraska Common
was uninjured. Photographed May 25, 1925. (Courtesy of T. A. Kiesselbach,
Nebraska Agricultural Experiment Station.)
introduction of Grimm alfalfa, which largely solved the whiter-
hardiness problem, wiping out the advantage gained by selection for
hardiness in Common alfalfa, and also depriving breeders of a definite
goal for selection. In other words, for the moment no great catas-
trophe threatened alfalfa, and most people, including the breeders,
were content to let well enough alone.
But events were already developing that brought a great revival of
interest in the improvement of alfalfa and other forage crops.
New Problems Appear
Crowding into compact communities leads to peculiar problems
with plants as with human beings. Growers will tell you they can
remember when they could plant alfalfa and leave it down almost
any number of years without any trouble. This cannot be done any
longer. The problem of winter hardiness was largely overcome by
the general use of Grimm and other cold-resistant varieties, but
138004° — 37 72
1130 YEARBOOK, 1937
another major problem appeared and became increasingly insistent.
It manifested itself in the lolling out of stands after 2, 3, or 4 years
of production. No one knew what was causing the trouble. Finally
it became so serious that Department of Agriculture workers under-
took to determine the underlying cause.
Finally Jones and McCulloch (IS) found the disease was produced
by a hitherto unknown organism, a bacterium to which was given the
Figure 5. — The original alfalfa nursery at Kedfield, S. Dak., from which Ladak was
selected. The seed was sent to the United States Department of Agriculture from
the Province of Ladakh, in northern India, in 1910 and was planted in 1914. Photo-
graphed July 20, 1915. The entire acreage of the Ladak variety now being grown in
the United States came originally from the two rows marked liy the arrow. The light
color of the rows is caused by the profuse bloom, the preponderance of which was
yellow in color. (Courtesy of S. Garvcr.)
name Aplanobacter insidio&um McCulloch, the insidious Aplanobaeter,
more recently changed to Phytomonas insidiom (McCulloch) Bergey
et al. The disease it caused was called bacterial will. Since i(s dis-
covery in 1925, apparently increasing inroads have, been made by the
disease until at the present time it is known to occur from the Atlantic
to the Pacific and from the Northern States to the southwestern bor-
der. It was apparently most severe in the river valleys of Nebraska
and Kansas at first, but it is now found in considerable abundance
eastward through Iowa, Illinois, Indiana, Michigan, Ohio, Wisconsin,
and other States.
Of the approximately 11)4 million acres of alfalfa harvested for hay
in the United States in 1934, the 1934 census shows that over 7%
million acres were grown in the 14 North Central Stag's bounded on
the east by Ohio and on the west by Colorado. At the present time
bacterial wilt is prevalent throughout this region, although it is more
serious in some localities than in others. In this region, too, alfalfa
is usually allowed to remain as long as there is a, good stand. When
it kills out it must be plowed and another field planted to maintain
a hay balance. The available domestic alfalfas such its Grimm, 1 lardi-
gan, and Common are very susceptible to the bacterial wilt disease
ALFALFA 1131
and kill out, where the disease is severe, in from 2 to 4 years. Figure
6 shows the ravages of bacterial wilt in tlie domestic varieties in field
plots at the Kansas Agricultural Experiment Station.
Bacterial wilt annually destroys hundreds of thousands of acres of
alfalfa, with aggregate losses equivalent to those that would be expe-
rienced by farmers as a result of flood, drought, or any other major
disaster. These losses include not only the crop destroyed by the
■■
Figure 6. — Experimental plots at the Kansas Agricultural Experiment Station, Man-
hattan, Kans., demonstrating resistance or lack of resistance of different varieties to
bacterial wilt, the plots with a poor stand being covered with weeds, a, Kansas
Common (poor stand); b, Turkistan F. C. 19303 (good stand); c, Turkistan F. C. 19304
(good stand); d, Grimm (poor stand); e, Ukranian F. C. 19315 (poor stand);/, Turk-
istan F. C. 19316 (good stand); g, Kansas 308 — a resistant selection from Kansas
Common (good stand); h, Dakota Common F. C. 16081 (poor stand); i, Argentine
F. C. 15996 (poor stand); j, Cossack F. C. 18836 (fair stand). These plots were
planted in the fall of 1930; photographed September 1936. The greatest decrease in
stand took place during the third and fourth years. (Courtesy of C. O. Crandfield,
Kansas Agricultural Experiment Station.)
disease but also the cost of seeding and the loss of production from
the land until a new crop is established. If, through the use of resist-
ant strains, growers could maintain stands of alfalfa for even 2 years
longer, they would be able to save millions of dollars.
Considerable preliminary work indicated that cultural practices in
general would not control the disease. The only avenue of approach
that offered possibilities was a breeding program. For a number of
years Westovcr and his coworkers, plant explorers of the Department
of Agriculture, have been gathering alfalfas from remote parts of the
globe. This collection has progressed until at the present time approx-
imately 1,000 different strains of alfalfa are growing in various nurs-
eries in the United States. Some of these were gathered in areas
where the natives had never seen or heard of an automobile. Of the
alfalfa strains tested from every continent, and almost every country,
practically the only strains having decided resistance to bacterial wilt
have been found in the region around Russian Turkistan, northern
India, western China, and northeastern Persia. Even some alfalfas
1132 YEARBOOK, 1937
of the wild type and the Medicago jalcaia strains found in this region
have shown resistance to bacterial wilt. The objective of the breed-
ing program, then, is to combine the good qualities of commercial
alfalfas such as Grimm and Common with the bacterial wilt resistance
found in the Turkistan alfalfa.
PRESENT ALFALFA IMPROVEMENT WORK
As already indicated, both new problems and new advances in plant
breeding have greatly stimulated alfalfa improvement. At the present
time a relatively large number of breeding projects are being started
or have recently been started, and there is a great deal of interest on
the part of almost all experiment stations, whether or not they are
themselves actively engaged in alfalfa-improvement work. In order
to make the present status of alfalfa improvement clear, the work that
has already been done both in the United States and abroad will be
briefly summarized.
Correlation of Charactkhs
When selection is desired for a certain character, it is often desirable
to determine, if possible, what other characters of the plant are asso-
ciated with it. Sometimes certain characters are inherited together.
By selecting for one, it may then be possible to secure the other also.
This association of characters frequently presents difficulties. In
alfalfa, for example, selection for increased forage production usually
gives at the same time a more coarse, sparsely leaved plant of poorer
quality. In 1914 Freeman (11) published a paper of interest from the
standpoint of selection of material. He studied correlations between
various characters in alfalfa and, among others, found positive correla-
tions indicating that nitrogen content is associated with the percentage
of leaves, and green weight with both the average number of stems and
the average height. He found negative correlations indicating that
greater forage yield is associated with smaller percentage of leaves ;
smaller percentage of leaves with greater height; smaller number of
stems with greater average height. There was no significant correla-
tion between thickness of stand and percentage of leaves.3 Freeman
concludes (11, p. 867):
In economic plant breeding one frequently encounters physiologically iiegative
correlations such as those, in alfalfa, between height and stooling capacity,
height and percentage of leaves, and between yield and quality. In seeking im-
provement, therefore, the breeder must recognize and make use of these facts
in the interpretation of results obtained, and also search for races which violate
such naturally antagonistic correlations to the greatest possible extent.
Hackbarth and Ufer (IS) found a relatively high positive correlation
between forage yield and height4 and also a positive correlation
between height of stem and length of internode and coarseness of stem.
r
3 Correlation between nitrogen content and percent leaves 0. G0±0. 00
Correlation between percentage ofleaves and thickness of stand _ __ .05± . 10
Correlation between percentage of leaves and forage yield — . 39± .09
Correlation between percentage of leaves and height (height 27 to 32 inches) .. ... -.58± .06
Correlation between green weight and average number of stems .r)7± .07
Correlation between green weight and average height _ 25± .09
Correlation between average height and number of steins — .25± .09
Correlation between average height and percent leaves. -.4()-± .09
* r=0.851.
ALFALFA 1133
Thus high-yielding plants were tall and upright but of low quality
because they had long internodes, were sparsely leaved, and had thick,
woody stems. They suggest, however, that the correlation is not
absolute and that with a sufficiently largo number of plants to choose
from it might be possible to obtain the desired combination of height
and quality. Of especial interest is the finding of a positive though
slight correlation5 between forage production and seed production.
Since it is considered by many that high forage yield militates against
high seed yield, it is noteworthy that they found a number of lines
(clones) in which high yield of forage was associated with high seed
production. Fleischmann (10) has also found strains that combine
relatively high forage and seed yield. In this connection Helmbold
(14) has found some correlation between the following characteristics
and high seed production, and selection for those characteristics may
help attain the desired end:
(1) A definite (closed) blooming period.
(2) Large flower clusters.
(3) Great individual ability to set seed. (He believes the female parent has a
greater bearing on seed productivity than the male.)
(4) Many coils per pod with high seed number per pod.
(5) Least possible shattering of seed.
Other workers, including Kiesselbach and Anderson in Nebraska
and Willard in Ohio, have also found a very high_ correlation between
nitrogen content and percentage of leaves. Thus it seems evident that
for a higher quality crop it is necessary to have a high percentage of
leaves and also that the plant retain those leaves until harvest. Thus
disease resistance as well as inherent leanness is involved, because
most of the leaf -spot diseases, for example, tend to defoliate the plant.
Hybrid Vigor
The question of how much crossing naturally occurs in alfalfa
brings such different answers that there is obviously no exact informa-
tion on the point. Waldron found 42.7 percent crossing between
purple and yellow, the yellow being the female parent, while he found
7.5 percent crossing in the reciprocal, the purple being the female
parent. As high as 80 percent crossing has been observed in Nebraska
between closely associated plants of the purple-flowered (Medicago
sativa) and yellow-flowered (M. jalcata) alfalfa, the female again
being yellow. It is more difficult to determine the crossing between
purple-flowered strains of similar origin because of the difficulty of
determining when a cross is obtained. This difficulty is now being
overcome in the production of "testers" by at least three experiment
stations. These include a strain produced by the South Dakota
station with pure white flowers, the character_ acting as a simple
recessive. Another strain produced at the Wisconsin station has
red roots, also simply inherited; and the Nebraska station has a strain
producing four or five leaflets instead of the usual three. These
strains all have the M. sativa type of flower, and by their use reliable
information should be obtained on the amount of natural crossing,
the distance necessary for isolation, and possibly on the activities of
various insects.
5 r=0.202.
1134 YEARBOOK, 1937
A considerable body of facts bearing on the question of the influence
of self-fertilization on an alfalfa population is gradually being estab-
lished. The work of Kirk (17), Williams (31), Torssell (26), Dann
(7), and others suggests, on the whole, decrease in productivity of
both forage and seed yield when plants are self-fertilized. The
decrease is very marked in most cases; for example, Williams (31)
reports that 14 parent plants produced an average of 2,433 seed per
plant, while the average yield of the first-generation selfed progeny
was only 301 seeds. Kirk found that the first generation selfed pro-
duced only 62 percent as much as the cross-fertilized parent, and the
second selfed generation only 30 percent as much as the original
parents.
The German workers, including Dann (7), also found a decided
decrease in seed production with self-fertilization as compared with
cross-fertilization. Helmbold (14) found that crossing gave a higher
percentage of pods than selfing. By crossing with foreign pollen,
24.86 percent of the flowers formed pods. With close pollination
(pollen from the same plant but different flowers) 18.26 percent formed
pods, and with strict selfing 17.54 percent formed pods. Crossing
also gave the highest number of seeds per pod, an average of 2.34,
while inbreeding gave the least, an average of 1.38 seeds per pod.
Most workers agree that there is no self-sterility, in the true sense, in
Medicago sativa or M.jalcata.
Tysdal and Clark (27) found decided decreases of seed production
in self-fertilized lines as a general rule, but point out several instances
where selection for seed productivity increased production, particu-
larly in Turkistan lines, which as a rule are naturally low in seed
yield. These lines were carried into the fourth generation of selfing
and represent a decided improvement in the inherent ability to set
seed over the original parent. Kirk (18) has isolated a strain of
alfalfa during the course of his breeding work that he characterizes as
"autogamous", that is, it is extremely self-fertile and sets seed readily
without manipulation.
The seed production resulting from hybridization compared to that
of the original parental stock has not been so carefully worked out.
It is evident that open pollination or cross-pollination between selfed
lines brings them up nearly to parity with the open-pollinated parents,
but there are very few definite examples, if any,' of large increases
attributable to hybrid vigor. Most of the comparisons have been
with the progeny of self-fertilized individuals and not with the original
parent, and the relative improvement in the cross is therefore difficult
to determine. Carlson (5) found decided decrease in seed production
upon self-fertilization, and then when open pollination — with no way
to determine the amount of crossing — was allowed, seed production
increased over that of self-pollination but still did not reach that of the
open-pollinated parents. In the work reported up to the present
time it has not been possible to recombine desirable inbred strains
with the object of producing a superior first-generation hybrid, as is
being done with corn, because such inbred strains were not available;
but at present there are a number of lines that have superior germ
plasm with respect to seed production as well as other desirable
characters.
ALFALFA
1135
The available data on the influence of self-and cross-fertilization on
forage production somewhat parallel those on seed production.
Kirk (16) found the following percentages of forage yields: Cross-
fertilized, 100; first generation selfed, 81 ; second generation selfed, 72;
third generation selfed, 53 (fig. 7); but lie also found certain second-
and third-generation selfed lines that produced 100 percent or more as
Figure 7. — A, Representative alfalfa plants from strain no. 22, showing reduction in
vigor due to self-fertilization: a, Open-fertilized; b, first generation selfed; c, second
generation selfed. B, Representative alfalfa plants from strain no. 3, showing reduc-
tion in vigor due to self-fertilization: a. Open-fertilized; b, first generation selfed; c,
second generation selfed. (Courtesy of I .. E. Kirk, Dominion Agrostologist, Ottawa,
Canada.)
compared with the original parent. This coincides in general with
results of other workers, there being not such a veiy great decrease in
forage production of some lines, and a tremendous variability with
respect to the reaction of different lines — some showing great loss of
vigor, while others show very much less. It must be admitted, how-
ever, that the chance of obtaining a superior forage-yielding strain
of alfalfa by self-fertilization appears rather remote at the present
time.
As in the case of seed production, most of the comparisons in forage
production are between open- and self-pollinated lines. Waldron
(29), however, as far back as 1920 pointed out hybrid vigor in crosses
between two alfalfa species. He allowed natural crossing to take
place between Medicago sativa and M. jalcata. Subsequently he
obtained yield data from the first-generation-hybrid individuals com-
pared with other individuals produced by normal pollination within
the species. He found an increase in forage yield of 51 percent of the
M. sativa X the M. jalcata hybrids over the pure M. sativa, and 43
percent increase of the M. jalcata X M. sativa hybrids over the pure
M. jalcata.
1136 YEARBOOK, 1937
This is an interesting observation, particularly in view of the fact
that the most widely cultivated alfalfas, in both Europe and North
America, are considered to be the result of a natural cross between
these two species. Thus without knowing it commercial growers are
probably taking advantage of hybrid vigor. In a study of the varie-
gation in flower color of 64 strains and varieties of European alfalfa,
Waldron (28) found only 5 that did not show any variegation, and 3 of
these were Turkistan. Hembold (14) states that in his opinion the
appearance of any color but pure purple in the flower surely indicates
foreign crossing in the M- sativa group, and as a rule the introduction of
M.falcata blood.
The general results of inbreeding and crossing in alfalfa point to the
strong possibility of hybrid vigor being obtained for forage yield if the
proper combinations of lines are made. The results also point to the
possibility of using species crosses to effect improvement. In a later
paragraph more information is given on various species that may
have possibilities for crossing.
Progress in Selection for Disease and Cold Resistance
In the replies from questionnaires sent to practically all alfalfa
workers in the world in connection with this survey, many indicated
that they were selecting for cold resistance and others that they were
selecting for both cold and disease resistance. In the past Grimm
alfalfa was an outstanding example of natural selection for cold
resistance. The introduction of various lots of seed and subsequent
selection and increase, as in the case of Cossack, Ladak, and other
varieties, resulted in the production of additional material of high
cold resistance.
In many projects selection is being carried on with the object of
purifying strains and making them homozygous for certain character-
istics, then recombining the lines to form new varieties. Such work
has advanced to the point where some information has been obtained
on the breeding behavior of lines, but very little on the behavior of
the recombinations.
As a result of a study of the reaction of selfed lines to cold, Kirk
(16, p. 15) states:
Inheritance has clearly played an important part and segregation into hardy
and non-hardy lines is plainly indicated in the second generation of self-fertiliza-
tion. Strains IV and VII may be cited as obvious cases in which lack of hardiness
has been transmitted in some degree from one generation to another. In one
second generation line of strain IV, every plant was winter killed. [The cross-
fertilized parental stock of strain IV winter-killed 28 percent.] Lines III and
XIII are notable illustrations of segregation in the second generation of selfing
for hardy and non-hardy families of plants.
In striking contrast to the strains in which inherent nonhardiness made an
appearance are * * * strains * * * in which practically no winter-
killing occurred.
Waldron (28) found segregation for cold resistance with one genera-
tion of selfing, and he also obtained increased cold resistance by selec-
tion of mother plants — indicating a great heterozygosity or mixture
of inheritance in individuals with respect to this characteristic.
A number of superior lines have been segregated by various workers
in the United States. Wisconsin, Kansas, New Jersey, Michigan, and
ALFALFA 1137
Nebraska have had rather intensive improvement programs under
way, and progress is reported in fixing desirable characters such as
cold and bacterial wilt resistance in certain lines. Peltier and Tysdal
{28) report that selfing alfalfa through the fifth generation has in-
creased the homozygosity for bacterial wilt resistance — that is, a
larger and larger percentage of the plants were resistant — provided
selection for this character was carried on during the inbreeding
process. If no selection for disease resistance was practiced during
the inbreeding process, a rather marked decrease in bacterial wilt
resistance occurred from generation to generation, although some few
fines were consistently high in bacterial wilt resistance. Practically
the same results were obtained with cold resistance. Selfing without
rigid selection for cold resistance and elimination of the cold-susceptible
individuals resulted in a marked decrease in resistance, taking the
population as a whole. There was, however, great variation and
segregation in different lines, as has been found by other workers.
Thus, when the cold-resistant segregations were selected by means of
artificially controlled freezing tests, the cold resistance of superior
lines was maintained in spite of self-fertilization. It was also found
possible to obtain high bacterial wilt and cold resistance either in the
same lines or independently, thus indicating independent inheritance.
Figure 8 shows two hybrids relatively resistant to bacterial wilt, as
compared with the bacterial wilt-susceptible Grimm variety.
Brink, Jones, and Albrecht (3) at the Wisconsin station report
segregation for bacterial wilt resistance in selfed lines from Hardistan
alfalfa, some having a very high degree of bacterial wilt resistance.
They state (3, p. 642): "Resistance to bacterial wilt in alfalfa behaves
in inheritance as an intergrading character and probably rests upon
a complex genetic basis. A factorial interpretation is at present
impossible."
In certain crosses between resistant and susceptible lines the same
workers found varying percentages of resistant offspring. In the
case of a Turkistan X Hairy Peruvian cross, 58 percent of the second-
generation offspring were resistant, while a Turkistan X Grimm cross
gave relatively few resistant segregates.
Thus while complete success has not yet been attained in the fight
against winter hazards and disease, it is safe to say that remarkable
progress has been made in obtaining fines that are superior in these
characters. These lines contain the necessary genetic stability for
these characters, and the next step will be to combine them to produce
a variety with as much bacterial wilt resistance as is now found in
any commercial variety, or even more, together with such desirable
characters as high forage and seed yield, freedom from leaf diseases,
and other attributes. To say that this is an easy task is to under-
estimate the difficulty of the problem and the whims and caprices of
nature.
In the alfalfa-improvement work, the Department of Agriculture
is cooperating with a number of State stations, among which the work
in Kansas, Wisconsin, and Nebraska has been longest in progress.
At each of these institutions superior strains are now available, some
strains having more than twice the bacterial wilt resistance of the best
commercial varieties. The Wisconsin station reports that among its
1138
YEARBOOK, 193 7
most promising material are lines having very high cold resistance
selected out of hardy varieties, and also some bacterial wilt resistance
found in occasional plants from well-known and highly susceptible
American varieties. The Kansas station has also reported increasing
the bacterial resistance by selection in the Kansas Common strain.
The Nebraska station has promising lines developed from plant
«a rj^*k*r» ,.%jg
«r ;
i,
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Figure 8. — Looking down on lliree strains of alfalfa artificially inoculated with the
bacteria causing alfalfa bacterial wilt, grown in the Nebraska Agricultural Experiment
Station greenhouse: a, Cross between a bacterial will -resistant Turkislan selection
and Medicago falcata; b, Grimm (originally a natural cross between A/, saliva and A/.
falcata); c, a cross between bacterial will-resistant selections from Turkistan and
Ladak. All three had an equal number of plants when inoculated, but Grimm has
been almost completely killed by the disease, while the two resistant crosses maintain
a stand. (Photographed 4 months after inoculation.)
selections from old fields of the State, foreign introductions, and the
Ladak and Cossack varieties.
The New Jersey station has had selection and hybridization in
progress for some time and reports the possibility of selection for a
type of root resistant to heaving, as well as selection for adaptation
to particular soil conditions.
Various stations now also have access to strains with rhizomes or
underground stems. These are particularly interesting from the
standpoint of pasture types and erosion control, as they form a matted
growth and bind the soil.
Relation of Insects to Alfalfa Improvement
There is some division of opinion, but in the main considerable agree-
ment, regarding the kinds of insects that assist seed setting in alfalfa.
Practically all workers agree that the leaf cutter bees (MegachUe spp.)
ALFALFA 1139
are very effective in causing tripping or forcing of the pistil out of the
keel. Piper et al. (25) found the bumblebee (Bombus spp.) to also
be fairly effective for tripping^ They found that butterflies caused
practically no tripping, and this was true also for moths and other
night-flying insects. The ability of the honey bee (Apis melltfera L.)
to trip alfalfa flowers is not so easily clarified. Piper et al. found that
honey bees tripped only from 0.3 to 4.7 percent of the flowers visited
and many visits to the flower were required before tripping was
effected. Dwyer (9), of Australia, has found that honey bees cause a
considerable amount of tripping and has suggested the use of honey
bees in cages in breeding work. Michigan workers have also found
the honey bee to be effective when confined to small areas. Helm-
bold (14) states that honey bees collecting pollen cause tripping and
attributes more tripping to them than to bumblebees. He also says
that the following bees are effective in tripping alfalfa flowers: Ma-
cropis labiata F. (female), Melitta leporina Panz., and Anthophora
bimaculata Panz.
There is no doubt from the work of numerous investigators that
insect visitation under most conditions will improve seed production,
and it is probable that insects can be used to advantage for controlled
pollination in certain breeding and improvement work.
There is some evidence that progress can be made in selecting lines
resistant to harmful insects. Painter and Grandfield in Kansas have
selected individual plants that are much more resistant to aphids
(Illinoia pi.si Kalt.) than the average of the variety. Some workers
have also found individual plants that seem to carry resistance to
leafhoppers (Empoasca spp.). At present these represent only
possibilities in superior germ plasm. Insects that harm alfalfa from
the standpoint of seed production, upon which little or no selection
for resistance has been done, include the clover seed chalcid (Brucho-
phagus gibbus Boh.), certain species of bugs of the genus Lygus, and
Say's stinkbug (Chlorochroa sayi Stal).
The Alfalfa Improvement Conference
In June 1934 a meeting of 27 alfalfa workers from 7 States
and the District of Columbia was held at Lincoln, Nebr., and at
this meeting attention was given to the formation of an informal
association for the benefit of all workers interested in alfalfa improve-
ment. In order to get the reaction of the eastern men it was decided
to call another meeting to be held in connection with the American
Society of Agronomy meeting at Washington, D. C, in November'
1934. Nineteen States, the District of Columbia, and Canada were
represented by 54 workers. After a thorough discussion a committee
of five was appointed, composed of H. L. Westover, R. A. Brink,
T. A. Kiesselbach, D. W. Robertson, and H. B. Sprague, to develop
plans and methods for a permanent alfalfa improvement conference.
This committee called a meeting of all interested workers to be held
in connection with the meeting of the Corn Belt section of the Amer-
ican Society of Agronomy at St. Paul, Minn., June 1935, at which
time final organization of the conference took place. At this meeting,
representing 15 States and the District of Columbia, with an attend-
ance of 78 workers, the following motion was adopted:
1140 YEARBOOK, 1937
That the guidance of the Alfalfa Improvement Conference be in the hands of
an executive committee of five, consisting of H. L. Wcstover, permanent secre-
tary, and four additional members, one of whom would be chairman, to be elected
biennially at the conference to be held in conjunction with the Chicago meeting
of the American Society of Agronomy; and that summer conferences be held in
alternate years at an experiment station where alfalfa investigations are in prog-
ress, the time and place to be determined by the committee.
The following were elected as members of the executive committee
to serve until the fall of 1937: R. A. Brink, chairman; T. A. Kiessel-
bach, H. B. Sprague, and D. W. Robertson. In Mr. Wcstover's
absence on plant exploration trips, H. M. Tysdal has been acting
secretary.
Since its inception and organization the Alfalfa Improvement
Conference has been active in disseminating information on progress
in alfalfa breeding, has taken an active interest in plans for seed
increase of desirable improved strains under isolation, has assisted
in the exchange of breeding material, and at the biennial summer
meeting held at Madison, Wis., in June 1936, laid the foundation of a
cooperative program of testing new strains. In this cooperative
testing two types of nurseries will be used — (1), an "observation"
nursery composed of duplicate rod rows with appropriate standard
checks, and (2), an advanced nursery composed of perhaps five or
six replications of multiple-row plots. Yields will be taken on the
latter nurseries, and also, where possible, on the former.
It is planned to have a considerable number of observation nurseries
scattered throughout the country so that experiment station workers
will have an opportunity of testing out the available new strains for
their own conditions, and this will enable them subsequently to make
intelligent varietal recommendations to alfalfa growers of their own
States. The advanced nurseries will be located in representative
areas to test out any definite regional adaptations that are found in
the improved strains. One or more tests are also contemplated in a
recognized alfalfa seed producing section to test this character. In
addition to these cooperative field tests, attempts will be made to
include testing under controlled conditions for such characters as
resistance to diseases, to insect pests, and to low temperatures.
The Alfalfa Improvement Conference has already proved itself
to be a vital force in coordinating the alfalfa improvement work
of the United States. Reports of the conferences already held
may be obtained from the Division of Forage Crops and Diseases,
Bureau of Plant Industry, United States Department of Agriculture,
Washington D. C.
Methods and Objectives of Present-Day Alfalfa Improvement
Even the most optimistic workers fail to see how it would be
possible to produce one variety of alfalfa that would be the best for
all sections of the country. Some workers, however, recognize a
need for the development of strains of alfalfa especially suited to at
least four general regions: (1) The northwestern region, north of the
southern boundary of Nebraska and west of the eastern boundaries
of North Dakota and South Dakota; (2) the northeastern region,
which may roughly be designated as the area bounded on the west
by the western boundaries of Minnesota and Iowa and on the south
ALFALFA 1141
by a line representing approximately the southern boundary of
Pennsylvania; (3) in the middle region, including Kansas and Oklahoma
and the surrounding territory eastward and westward; (4) the south-
western region, including southwestern Texas, southern New Mexico,
Arizona, most of California, and the extreme southern parts of the
United States along the Gulf of Mexico.
In regions 1 and 2 it is essential to have an alfalfa of high cold re-
sistance. Bacterial wilt can also be found throughout these regions,
but it is severe only in those areas where moisture and other conditions
are favorable; it is not serious as yet in the dry-land areas or in the
eastern regions where short rotations are the rule. However, it causes
severe damage in parts of Ohio, New Jersey, and other Eastern States.
The chief difference between the requirements for regions 1 and 2 relate
to resistance to various leaf spots, particularly the leaf spot caused by
Pseudopeziza medicaginis (Lib.) Sacc. and leaf blotch (Pyrenopeziza
medicaginis FckL), and also to dormancy habits and resistance to potato
leafhopper yellows. Cold-resistant Turkistan alfalfa has been fairly
successful in region 1 but not in region 2, chiefly because of its suscepti-
bility to leaf spots and the fact that in some cases its slow recovery after
cutting allows grasses to encroach. At one experiment station in the
Union of Soviet Socialist Republics, selections less susceptible to leaf
spot have already been made, and it does not appear impossible that
eventually a strain can be produced that will combine the qualities
necessary for adaptability to both regions, 1 and 2. This would be all
the more desirable because seed is often produced in the western area
to be used in the eastern area. Also there is some evidence indicating
an increase in the severity of bacterial wilt in eastern States, which
would make bacterial wilt resistance desirable for this region.
In region 3, cold resistance is a less important factor, but it can by
no means be entirely neglected. Bacterial wilt resistance is desirable
if not necessary for many areas, and it seems probable that if a strain
can be produced combining bacterial wilt resistance and the desirable
habit of growth of Kansas Common alfalfa, it will be ver}r well adapted
for this region.
In region 4 the climate is so mild that cold resistance need not be con-
sidered, although there is apparently considerable difference in ability
of the foliage of different strains to resist frost, and it is desirable to
select for this character. Since tests have shown that the nonhardy
alfalfas grow more rapidly and give better yields of hay in this region,
selection work can be confined largely to southern types. Bacterial
wilt has not been important in this region, although it has been found.
Fortunately certain Persian introductions of the nondormant type have
shown some bacterial wilt resistance and these are available for selec-
tion and breeding work for the region.
It is apparent from the foregoing that a large amount of selection and
recombination of characters must be accomplished before the desirable
alfalfas are obtained. Fortunately much of the foundation stock,
including lines of high resistance to certain diseases and to cold, is
already available. A cooperative arrangement with the various States
to give accurate information on the adaptation of all new strains pro-
duced is now available under the auspices of the Alfalfa Improve-
ment Conference.
1142 YEARBOOK, 1937
The ultimate objective will be the combination of as many desirable
characters in a single individual strain as possible. Most piant breed-
ers constantly bear in mind and guard against the possibility that selec-
tion for one character, such as bacterial wilt resistance, may actually
lead to the development or retention of characters undesirable in other
respects. For example, bacterial wilt resistance can readily be ob-
Figure 9. — Emasculation of alfalfa flowers by suction. The class tube is held over the
stigma and stamens, and the suction (in this instance supplied by a rubber tube con-
nected to the intake manifold of an automobile) removes the anthers and pollen.
If all the pollen is not removed, a jet of water is applied to the stigma and suction
finally removes all trace of pollen.
tained in Turkistan lines, but the strain is still undesirable because of
other characters, including high susceptibility to leaf diseases.
Naturally present-day alfalfa breeders use a wide variety of methods
in attacking the problem of improvement, although the underlying
principles are the same. In hybridization work where emasculation
is desired most American workers use the suction method or a combina-
tion of suction with a jet of water directed on the stigma. The suction
method operates on the principle of a vacuum cleaner and is illustrated
in figure 9.
It has been found advantageous not to allow the stigma to strike the
standard or any other object when it is tripped or forced out of the keel
for emasculation. It has also been found that in general it is unneces-
sary to emasculate the flower at a very early stage; emasculation is
usually delayed until full bloom, even though the anthers have become
ripe. If the pollen is carefully removed, apparently there is little
danger of self-fertilization, and foreign pollen can then be applied
immediately.
ALFALFA
1113
Figure 10. — Increase of seed of selected lines of alfalfa in ike greenhouse at the Nebraska
Agricultural Experiment Station. The greenhouse is screened against insects, and the
flowers are tripped by hand, insuring self-pollination. Good seed setting can usually
be obtained in the greenhouse even in unfavorable seasons, although temperatures
often reach 120° F. inside.
sMmt/mmmim
Figure 11. — Seed increase of a selected alfalfa strain in an isolated block. Such a
plot must be separated from any other by at least 20 rods; in this case the separation
was about a quarter of a mile. The plants were transplanted to irrigated land in
western Nebraska in the spring of 1936 from seedlings started at the United States
Yuma Field Station, Bard, Calif., in December 1935. These plants produced a fair
amount of seed the first year. The plot is surrounded by corn and sugar beets.
1144
YEARBOOK, 1937
Selfing is accomplished by the use of bags, screen cages, or screened
greenhouses, the flowers usually being artificially tripped, although
not always. Some strains have been produced that set seed without
any manipulation of the flower. Figures 10, 11, and 12 show some of
the ways in which the problem of seed increase of selected lines is
being met.
Perhaps of greater interest than details of technique are the principles
followed in the breeding program itself. Some workers allow open-
Figure 12. — Small, portable thresher for threshing both single plants and increase
blocks of alfalfa. The single-plant material is rim only over the rubber drum with
apron shown at the right, while larger quantities are put through the cylinder, and pods
tbat are not threshed fall through the screen and are then run over the rubber drum,
which rubs all the seed out. The rubber drum is powered through an automobile
transmission so the drum can be stopped when not in use, even though the cylinder
is going. The whole machine is mounted on the chassis of a car, and the motor of
the ear used as power. This thresher has proved very satisfactory for relatively
small lots.
fertilization in the nursery and select the best individual lines for
propagation, while others employ strict inbreeding methods with the
object of more rapidly fixing the characters desired and then recom-
bining if necessary. Still others use a combination of these methods.
Without doubt many alfalfa breeders are using the same method that
has produced such remarkable results in hybrid corn, as described by
Merle T. Jenkins in the 1936 Yearbook of Agriculture.
The problem of how to determine which lines when crossed will
produce a superior hybrid is of great interest to alfalfa workers. At
present the only way to find out is to try the lines in actual crosses,
and it is difficult to make as many crosses as are necessary to test all
ALFALFA 1145
combinations. Corn workers use the top-cross method rather exten-
sively at the present time for eliminating undesirable strains, and it
has been suggested that a modified application of the same principle
may be useful in alfalfa.
Evidence seems to indicate that long-continued inbreeding is not
necessary to fix desired characters sufficiently for practical breeding
purposes. If this is true a great deal of labor and time will be saved
and also a larger number of lines can be produced and tested.
The backcross method or its modifications,. as, for example, Richey's
"convergent improvement" method, is apparently not very much
used with alfalfa. Some type of backcross may be useful in such
a problem as combining the bacterial wilt resistance of Turkistan
selections with the desirable characters of Grimm, Cossack, or Hardi-
gan. The application of the backcross method is not simple when
the inheritance of resistance is complex, as is apparently the case
with bacterial wilt, but the method should not be overlooked when
it is yielding results in various other crops.
To obtain further information on the present status of alfalfa
improvement, questionnaires were sent to all experiment stations in
the United States and all foreign workers of whom there was a record.
Among 40 replies, 23, representing opinions from England, Germany,
Australia, and Canada, as well as the United States, indicated that
alfalfa breeding or improvement work was in progress. In the replies
to the question "What are the objectives in your selection or hybridiza-
tion work?" the following objectives were mentioned the number of
times shown:
Increased seed-setting capacity 10
Higher yield of good quality forage 8
Winter hardiness 8
Disease resi stance 8
A type suitable for grazing 5
Adaptation to different soil conditions 4
^Resistance to heaving inj ury 2
Insect resistance 2
Increase resistance to drought 2
Increase in protein content and loaf percentage 2
A type less susceptible to inj ury from early cuttin g 1
Larger seed 1
It is interesting to compare these replies with those obtained in
1934, given in the supplement to the Report of the Second Alfalfa
Improvement Conference. The most significant change is found in
the increased number of workers at present interested in selection for
a pasture type of alfalfa for grazing, and also the increased number
interested in selection for soil adaptation. This undoubtedly indi-
cates a trend toward the increased use of alfalfa for grazing and a
desire to use it on land to which it is at present not well adapted.
In the same questionnaire, in answer to the question "What prob-
lems and material need future attention?" the replies indicated further
studies would be desirable on —
(1) Technique in methods of hybridization.
(2) The mode of inheritance of various characters.
(3) Hybrid vigor, including interspecies crosses.
(4) Factors affecting seed setting in alfalfa.
(5) Fundamental research on the nature and control of various diseases.
138004°— 37 73 ++
1146 YEARBOOK, 1937
(6) The mosaic problem.
(7) Effective means of isolating pure seed for increase.
(8) Interregional testing, including hardiness and disease tests.
(9) Production of improved seed.
(10) The use of the backcross method, or modifications, in alfalfa breeding.
INHERITANCE AND CYTOLOGICAL STUDIES
Thekk is rather a large amount of literature dealing with the general
genetic behavior of alfalfa, but very little has been done on the in-
heritance of any given character. This is to be expected in a crop
worked with as little as alfalfa, but nevertheless it is a handicap to
the plant breeder in many respects. As self-fertilized strains having
a known inheritance are developed, more information of this kind
should be forthcoming.
Most of the work so far has involved crosses between the two con-
trasting species, Medicago sativa X M. falcata. In such a cross Koro-
hoda 00) has reported on the inheritance of flower color, shape of
leaves, and structure of the stem. With regard to the inheritance of
flower color in the purple X yellow cross, he states that the former
supposition that two or three hereditary factors were involved was
found to be inadequate. The results of his studies indicated at least
four factors, one for each fundamental coloration — cream, blue, and
violet — and one or two that intensify these colors.
"With respect to the shape of the leaves of the hybrid, the shape
typical of Medicago sativa was observed in the second generation in
28 plants, that typical of M. falcata in 196 plants, and an intermediate
in 424 plants. It was not found possible to calculate the relations,
assuming the existence of two, three, or four factors.
When examining the structure of the stem in the second generation,
stems of the type of M. jalcata were observed in 565 individuals, and
of the type of M. sativa in 30 individuals. Since the ratio of these
numbers (18:1) is close to 15:1, the workers assumed the existence of
two hereditary factors, with the falcata type dominant over the
sativa type.
MacVicar (22) reports the results of an investigation to determine
the inheritance of black and white seed coat characters in alfalfa and
whether or not the former could be utilized in breeding as a marker for
identifying improved strains. He says:
The available evidence indicated that the white seeded parent was homozygous
for a recessive factor which results in the absence of yellow pigment, and that the
inheritance of this character was comparatively simple. Inheritance of the black-
seeded character, on the other hand, was fairly complex, requiring the assump-
tion of at least three factor pairs. The original black seeded plant was thought
to have arisen as a single gene mutation. This gene, primarily responsible for
pigmentation of the seed coat, together with at least two modifying factors was
postulated as the most probable genetic factorial basis to account for the breeding
behavior of the original black seeded parent.
It was concluded that the character of black-seededness would be valueless
from a utility standpoint.
The cytological aspects of alfalfa have also been neglected until
recently, when several interesting papers have been published.
Among these is a paper by Fryer (12), summarizing much of what is
known regarding chromosome numbers in Medicago species, and
another by Cooper (6) on embryology, reporting the important fact
ALFALFA 1147
that according to his observations the lack of seed production in
various plants seems to be due not to lack of pollination or fertiliza-
tion but to failure of the ovule to develop after it has been fertilized.
In plants that fail to set seed after effective pollination takes place,
the young embryos abort. Direct evidence regarding the cause of
the abortion was not available, but it was believed to be an unbalanced
nutritional condition.
LITERATURE CITED
Anonymous.
1911. variegation op European ali-alfa. Science (n. s.) 33: 310-312.
Brand, C. J.
1907. PERUVIAN alfalfa: a new long-season variety for the
southwest. U. S. Dept. Agr., Bur. Plant Inchis. Bull. 118,
35 pp., illus.
Brink, R. A., Jones, F. R., and Albrecht, II. R.
1934. genetics of resistance to bacterial wilt in alfalfa. Jour.
Agr. Research 49: 635-642, illus.
Candolle, A. [L. P. P.] de
1914. origin of cultivated plants. 468 pp. New York and London.
Carlson, J. W.
1935. alfalfa-seed investigations in utah. Utah Agr. Expt. Sta.
Bull. 258, 47 pp., illus.
Cooper, D. C.
1935. macrospouogenesis and embryology of medicago. Jour. Agr.
Research 51 : 471-477, illus.
Dann, B.
1930. UBER DIE befruchtungsverhaltnisse der bastardluzerne
(medicago media), anderer medicago-arten und steinklee
(melilotus). Ztschr. Ziicht., A. Pflanzenziicht. 15: [366]-418,
illus.
Doyle, II. W., comp. and ed.
1916. alfalfa in Kansas. Kans. State Bd. Agr. Rcpt. 35, no. 138,
484 pp., illus.
Dwyer, R. E. P.
1936. LUCERNE BREEDING TECHNIQUE. A NEW SYSTEM OF CLOSE BREED-
ING. Imp. Bur. Plant Genetics: Herbage Plants, Herbage Rev.
4: 1-8, illus.
Fleischmann, R.
1926. BEITRAG ZUR ZUCHTUNG DER UNGARISCHEN LUZERNE. Ztschr.
Pflanzenziicht. 11: [211)-240, illus.
Freeman, G. F.
1914. PHYSIOLOGICAL CORRELATIONS AND CLIMATIC REACTIONS IN ALFALFA
breeding. Amer. Nat. 48: 356-368, illus.
Fryer, J. R.
1930. CYTOLOGICAL STUDIES IN MEDICAGO, MELILOTUS AND TRIGONELLA.
Canad. Jour. Research 3: 3-50, illus.
Hackbarth, J., and Ufer, M.
1935. ZtfCHTERISCHE BEOBACHTUNGEN AN LUZERNEKLONEN. I. E1NIGE
ZUCHTERISCH WICHTIGE KORRELATIONSXOEFFIZIENTEN. Zliohtor
7: [281]-284, illus.
Helmbold, F.
1929. UNTERSUCHUNGEN UBER DIE BEFRUCHTUNGSVERHALTNISSE, UBER
DIE BEDINGUNGEN UND UBER DIE VERERBUNG DER BAMENER-
ZEUGUNG BEI LUZERNE (MEDICAGO SATIVA UND BASTARDLUZERNE).
Ztschr. Pflanzenzueht. 14: [113]-173.
Jones, F. R., and McCulloch, L.
1926. A BACTERIAL WILT AND ROOT ROT OF ALFALFA CAUSED BY APLANO-
bacter iNSiniosuM l. MCC. Jour. Agr. Research 33: 493-521,
illus.
Kirk, L. E.
1927. self-fertilization in relation to FORAGE CROP IMPROVEMENT.
Sci. Agr. 8: 1-40, illus.
1148 YEARBOOK, 1937
(17) Kirk, L. E.
1932. FURTHER CONTRIBUTIONS ON THE TECHNIQUE EMPLOYED IN THE
BREEDING OP HERBAGE AND FORAGE PLANTS. Imp. Bill-. Plant
Genetics, Herbage Plants Bull. 7.
(18) and White, W.. J.
1933. autogamous alpalfa. Sci. Agr. 13: 591-593, illus.
(19) Klinkowski, M.
1933. lucerne: its ecological position and distribution in the
world. Imp. Bur. Plant Genetics: Herbage Plants, Bull. 12,
62 pp., illus.
(20) Korohoda, J.
1933. inheritance of certain characters of the hybrid of medicago
sativa and medicago falcata. Pain. Pai'ist. Inst. Nauk. Gosp.
Wiejsk. Pulawach (Mem. Inst. Natl. Polon. Econ. Rurale
Pulawy) 14: [378J-393, illus. [In Polish. English summary,
pp. 392-393.]
(21) McKee, R., and Ricker, P. L.
1913. nonperennial medicagos: the agronomic value and botanical
relationship of the species. It. S. Dept. Agr., Bur. Plant
Indus. Bull. 267, 38 pp., illus.
(22) MacVicar, R. M.
1935. inheritance of seed color in alfalfa. Sci. Agr. 15: 314-328.
(23) Peltier, G. L., and Tysdal, H. M.
1934. WILT and cold resistance of self-fertilized lines of alfalfa.
Nebr. Agr. Expt. Sta. Research Bull. 76, 26 pp., illus.
(24) Piper, C. V.
1909. REPORT OF THE COMMITTEE FOR BREEDING FORAGE CROPS: ALFALFA
and its improvement by breeding. Amer. Breeders' Assoc.
Rept. 5: 95-115.
(25) Evans, M. W., McKee, R., and Morse, W. J.
1914. ALFALFA SEED PRODUCTION: POLLINATION STUDIES. "C. S. Dept.
Agr. Bull. 75, 32 pp., illus.
(26) Torssell, R.
1929. SJALVSTERILITET HOS LUZERN (MEDICAGO SATIVA OCH M. MEDIA).
Nord. Jordbrugsforsk. Beret. Kong. A Helsingfors, K0benhavn.
Fjerdc, pp. 666-669.
(27) Tysdal, H. M., and Clark, I.
1934. IMPROVEMENT OF ALFALFA SEED PRODUCTION BY INBREEDING.
Jour. Amcr. Soc. Agron. 26: 773-780.
(28) Waldron, L. R.
1912. HARDINESS IN- SUCCESSIVE ALFALFA GENERATIONS. Amer. Nat.
46: 463-469.
(29)
1920. FIRST GENERATION CRpSSES BETWEEN TWO ALFALFA SPECIES.
Jour. Amer. Soc. Agron. 12: 133-143, illus.
(30) Westover, H. L.
1934. ALFALFA VARIETIES IN THE UNITED STATES. I". S. Dept. Agr.
Farmers' Bull. 1731, 14 pp., illus.
(31) Williams, R. D.
1931. self-fertility in lucerne. Welsh Plant Breed. Sta. Bull.,
Ser. H, no. 12: 217-220.
(32) Wing, J.
1912. alfalfa farming in America. 528 pp., illus. Chicago.
APPENDIX
Investigators Working on Alfalfa Improvement
The following list includes mainly the breeders and workers employed by institu-
tions that returned questionnaires on superior germ plasm in alfalfa. Nearly all
the workers listed as State agricultural experiment station employees devote
only a small part of their time to alfalfa-breeding investigations. The remainder
ALFALFA 1149
of their time is given to investigations on other crops. This is also true of some of
the field staff of the Division of Forage Crops and Diseases, Bureau of Plant Indus-
try, United States Department of Agriculture. Early workers are listed on page
1233. The names of alfalfa breeders listed for foreign countries were all given
in the returned questionnaires.
An asterisk (*) denotes United States Department of Agriculture employee.
United States
United States Department of Agriculture, Bureau of Plant Industry, Division of
Forage Crops and Diseases, Washington, D. C: H. L. Westover.*
California Agricultural Experiment Station, Davis: B. A. Marlson, F. N. Briggs.
Colorado Agricultural Experiment Station, Fort Collins: D. W. Robertson)
R. M. Weihing.
Kansas Agricultural Experiment Station, Manhattan: C. O. Grandfield.*
Kentucky Agricultural Experiment Station, Lexington: E. N. Fergus.
Michigan Agricultural Experiment Station, East Lansing: E. E. Down, S. T.
Dexter, H. M. Brown.
Minnesota Agricultural Experiment Station, St. Paul: A. C. Amy.
Montana Agricultural Experiment Station, Havre: M. A. Bell.
Nebraska Agricultural Experiment Station, Lincoln: T. A. Kiesselbach, H. M.
Tysdal.*
New Jersey .Agricultural Experiment Station, New Brunswick: H. B. Spraguo,
E.M.Hodges.
New Mexico Agricultural Experiment Station, State College: J. C. Overpeck,
G. N. Stroman.
New York Agricultural Experiment Station, Ithaca: C. H. Meyers.
Rhode Island Agricultural Experiment Station, Kingston: T. E. Odland, H. F.
A. North.
Utah Agricultural Experiment Station, Logan: R. J. Evans, B. L. Richards,
J. W. Carlson.*
Wisconsin Agricultural Experiment Station, Madison: R. A. Brink, A. II.
Wright, O; S. Aamodt, E. J. Delwiche (Green Bay), A. L. Bibby (Spooner),
A. M. Strommen (Spooner), L. E. Muskavitch (Ashland), F. R. Jones.*
Canada
Dominion of Canada Experimental Farms, Ottawa, Ontario. L. E. Kirk,
J. M. Armstrong.
Universitv of Saskatchewan, Saskatoon, Saskatchewan: T. M. Stevenson,
William J. White.
University of Alberta, Edmonton, Alberta: J. R. Fryer.
Ontario Agricultural College, Guelph, Ontario: R. Keegan, O. McConkey.
McGill University, MacDonald College, Quebec: J. N. Bird.
Australia
Bathurst Experimental Farm, Bathurst: W. T. Atkinson.
Grafton Experiment! Farm, Grafton: W. H. Darragh.
Riverina Experimental Farm, Yanco: W. H. PoggendoifT.
Hawkesbury Agricultural College, Richmond: N. S. Shirlow.
Wales
Welsh Plant Breeding Station, Aberystwyth: R. D. Williams.
Germany
Kaiser Wilhelm Institute, Muncliberg: J. ITackbarth, Dr. Schrock.
Sweden
Sveriges Utsadesforening, Svalof: N. Sylvcn, O. Holmgren.
Sverigcs Utsadesforening, Ultuna: R. Torssell.
Table 1.
Variety or strain
Grimm
Cossack
Baltic
Grimm 19A.
Ladak
Ontario Variegated .
Hardigan
Meeker Baltic.
Grimm 451
Grimm 6G6
Hardistan
Grimm, M. C_
Kaw
Kansas 308
S133
A number of strains...
Year
intro-
duced
1905
1907
ions
1909
1910
1910
1920
1920
1921
1925
1930
1931
1932
1933
1936
1920-30
-Historical summary of the development of improved varieties of alfalfa in the United States and Canada
Name and location of
breeder
Wendelin Grimm, Minne-
sota.
N. E. Hansen, South
Dakota.
Wheeler, South Dakota
do..
IT. L. Westover, Samuel
Garver, U.S. Department
of Agriculture.
C. A. Zavitz and coworkers,
Ontario.
F. A. Spragg, E. E. Down,
Michigan.
P. K. Blinn, Colorado
1. Bracken, L. E. Kirk,
Saskatchewan.
M. Champlin, L. E. Kirk,
Saskatchewan.
A. Hecht, T. A. Kiesselbach,
A. Anderson, G. I,.
Peltier, Nebraska.
J.N. Bird, Quebec
S. C. Salmon, C. O. Grand-
field, Kansas.
C. O. Orandfleld, Kansas..
R. D. Williams, Wales
F. A. Spragg, E. E. Down,
S. T. Dexter, H. M.
Brown, Michigan.
Superior characters
Yield, quality, winter hardi-
ness.
Winter hardiness, produc-
tivity.
Cold resistance, productivity.
Winter hardiness, produc-
tivity.
Yield, cold and drought re-
sistance. More resistant to
bacterial wilt than Grimm.
Winter hardiness, produc-
tivity.
Yield of hay and seed.
Yield, cold resistance, hay
quality.
Hardiness, yield
Seed yield
Bacterial wilt resistance-
Winter hardiness
Resistance to wilt and cold
Resistance to wilt and cold,
high yield.
Under test. Increased yields
on comparatively poor soils.
Superior seed production,
yield, and cold resistance.
Breeding method used
Natural followed by artificial
selection.
Selection from introduced
strains.
Natural selection..
Line selection.
Selection of introduced mate-
rial at Redfield, S. Dak.
Inbreeding mass selections
and strain building.
Selection..
Natural selection and selec-
tion.
Mass selection
Single plant line..
Selection
Recombination seifed lines
and strain.
Natural selection
....do
Builtupfrom 10 seifed lines.
Hybridization selection
Parent material
Seed brought by Grimm from
Germany.
Seed from Siberia...
Probably Grimm, although
not certain.
Grimm
Introduction from northern
India as Medkago fakala.
Variegated alfalfas from Baden
and Alsace-Lorraine and
various importations from
Europe (Norway) and the
original strain of Grimm.
Baltic
.do..
Present acreage
In State
produced
700, 000
Several Grimm introductions,
all tracing back to Minne-
sota Grimm.
Selection from Grimm ob-
tained from Lyman of
Excelsior, Minn.
Old Nebraska field, probably
of Turkistan origin.
Grimm stock 8, Grimm stock
5, obtained from University
of Minnesota in 1911, S. P. I.
Provence 34886..
Mainly Grimm and Canadian
Variegated.
Hardigan
(')
400, 000
20,000
4,000
1,000
375
'25
Else-
where
(s)
(3)
(')
(')
Ol
o
5, 000
Approximately 50 I 192S-36 | II. M.Tysdal, (J. h. Peltier,
| T. A. Kicsselbaoh, Nebras-
ka.
strains.
Unnamed
A number of strains.
Do_
Do.
Do.
CO
..! iu;so-3<i
i
Tjso-ao
ira-:«i
J. li. Fryer, Alberta...
R. A. Brink, F. R. Jones,
11. K. Albrecht, Wiscon-
sin.
II. B. Spraguc, Glenn Bur-
ton, New Jersey.
C. O. Grandfield, Kansas
G. C. Moe, C. n. Myers,
I"). B. Johnstone-Wallace,
New York.
Wilt and cold resistance, seed
production.
SclcctioninselMcrtilized lines, I PlanLs from old Nebraska
hybridization and selection i fields, iutroduclions from
in i'j. foreign countries, domestic
1 varieties including Cossack,
, Ladak, Medicayosp.
I Accumulation of hereditary Maternal line selection , Grimm, Wiley, Grimm, l>is-
i factors that contribute to j eo, Southworih's hybrid,
fertility. ; i and Ontario Variegated.
I Wilt and cold resistance, seed ! Selection in self-fertilized lines, , Grimm, Cossack, Ladak, j
production. ; hybridization. i Turkisl an, Kansas and Mon-
I tana Common, introduc-
tions. '
Adaptation for New Jersey : Mass selection, hybridization--! Peruvian, Medicago falcata, ■
conditions. i selected lines from other !
1 States. ,
Wilt resistance, Kansas Com- ' Selection in self-fertilized lines, : Kansas Common, Kaw, Tur- '
monlypc. j hybridization. kistan, introductions
Pasture types, seed setting
Hybridization, selection..
Grimm, Akdicago falcata.
f<)
(■)
(<)
C)
1 Unknown.
1 In Province of Quebec.
3 Xot. yet. distributed
' Not yet released.
1 Now in process.
fc — i
1152 YEARBOOK, 1937
Key to Some of the Commoner Species of Medicago
Pods not coiled, straight or curved; flowers yel-
low.
Pods not flattened.
Pods kidney-shaped, one seeded, style as Chromosome number (en)
long as ovary at time of blooming M. lupulixa 16
Pods straight or curved, several seeded, M. palcata '32
usually sickle-shaped, style never as long
as ovary.
Pods flattened, at least twice as broad as in
M. falcata.
Pods large, oval, many seeded M. platycaupa 16
(M. PLATYCABPOS).
Pods smaller, with about four seeds M. kuthexica 16
Pods spirally coiled.
Coil with an open center; plants perennial.
Shrubby, 4 to 10 feet high; flowers large, M. arrorea 32
yellow.
Herbaceous plants; flowers usually not yel-
low.
Pods but little coiled, less than a full M. hemicycxa 32
spiral.
Pods with one to several windings.
Flowers uniformly violet or blue M. sativa 32
Flowers variegated, white, yellow, and
blue.
Plants generally without rhizomes.
Plants glabrous or slightly pubes- M. media 32
cent.
Plants glandular pubescent, espe- M. oltjti-Vosa 32
cially pods and calyx and young
shoots.
Plants with long rhizomes; flowers, M. oaetl-la 32
seeds, and pods larger than in M.
media, pod with twro and a half to
four windings.
Coil with a closed center; flowers yellow; an-
nuals.
Pods generally spiny.
Spines in a double row, those at top of bur M. corontata 16
turned upward to form a double crown.
Spines not as above.
Leaves with a dark blotch in center; M. auabioa 16
seed with a projection by the hilum.
Leaves without a dark blotch.
Pods 7 to 10 mm across, spines from M. hispida 14
half to whole width of winding.
Pods as above, but spines shorter M. hispida dkn-tfoulata- 14
Pods without spines.
Pods small, about size of those of M. Ms- M. hispida oonhnh 14
pida.
Pods much larger.
Pods flattened; leaflet nearly orbicular. _ M. orbicularis 16
Pods nearly spherical; leaflets nearly M. scutellata 32
twice as long as wide.
• Also 10.
Brief Description of Certain Medicago Species With Particular Reference to
Their Economic Desirability
Medicago platycarpa is a low-growing perennial with large broad leaflets, yellow
flowers, and large flat pods, found mainly in Siberia. According to Hansen its
distribution is mainly along the edges of timberland and in open places in the native
ALFALFA 1153
timber, indicating that it might be adapted to sheltered regions such as the timber
sections of northern Minnesota and Wisconsin and westward into the Rocky-
Mountains.
AI. ruthenica is a small semicrect perennial with small narrow leaflets, yellow
flowers, and small pods. Hansen found this species growing wild in a section of
the Gobi Desert in nearly pure sand. In general it is found scattered in dry, stony
soils. As a fodder plant this species is greatly relished by the cattle, horses, sheep,
and camels kept by the Mongolian nomads. Its distribution is farther north than
that of Common alfalfa (Ad. saliva).
AI. arborea is the largest representative of the Aledicago genus, attaining a height
of upward of 10 feet. It is a native of the Mediterranean region of Europe and
docs not thrive in cold climates. It is cultivated to a limited extent in various por-
tions of its range, but as it gets woody too quickly and is less productive than AI.
saliva, that species is much more in favor.
AI. falcala is an upright to prostrate perennial with small elongated leaflets,
yellow flowers, and falcate pods. It is distributed over a wide range in eastern
Europe and western Asia. Apparently it combines readily with AI. saliva to form
many of the cultivated varieties such as Grimm and Cossack, which are classified
as At. media in the foregoing key. Many strains, though not all, are very cold-
resistant, and certain types also endure pasturing rather well. It is now being
used in breeding programs to a considerable extent.
A point of particular interest has recently been raised by Fryer (12), who found
different chromosome numbers in AI. falcala. In two strains he found the number
to be 2n = 32, while in another strain he found it to be 2n=16. It is probable
these two types would react differently in crosses.
AI. gaetula is particularly noted for its rhizomes, by means of which it spreads
readily like sod-forming grasses. It is now being used in crosses to produce pasture
and soil-binding types.
AI. glutinosa is a native of the Caucasus Mountains and Trans-Caucasia gen-
erally, especially of Armenia, where it is found up to an elevation of 7,500 feet.
It is found growing in a very dry upland region and is more vigorous than most
Aledicago species of Caucasia.
AI. hemicycla is found in the Caucasian region and is somewhat similar in mor-
phological type to AT. media. It is considered to be a natural cross between AI.
saliva and AI. falcala.
M. coronata is remarkable on account of its very high drought resistance. It is
an annual found in all parts of Palestine, but its occurrence on the mountain slopes
is particularly interesting, as the soil there is only an inch or two deep over the
rocks. The seed setting of this variety is also high.
McKce and Ricker (21) state that the nonperennial species of Aledicago consist
principally of bur-clovers, mostly annual plants native to the Mediterranean re-
gion. Spotted bur-clover (AI. arabica), California bur-clover (At. hispida), and
black medic (AI. lupidina) arc the only species now widely distributed in the
United States. The feeding value of bur-clovers, both those with and those
without spines, is good. Among the latter the three most promising arc AI. con-
finis, At. orbicularis, and At. arabica inermis.
IMPROVEMENT
IN SOYBEANS
W. J. MORSE, Senior Agronomist,
J. L. CARTTER, Associate Agron-
omist, Division of Forage Crops and
Diseases, Bureau of Plant Industry l
0.
"NE of the most striking agricultural developments of recent times
is the rapid rise of the soybean within the last few years from the posi-
tion of a substitute and emergency crop to a place of considerable
economic importance in American agriculture and industry. First
introduced into this country in 1804, it was grown for many years
only in gardens as a curious plant from the Far East. Its culture
has now spread over much of the territory east of the Mississippi
River, and it has become well established in the cropping systems of
this area as well as in the States bordering the west bank of the
Mississippi.
The high nutritive value of the plant and its seeds has made it
particularly valuable as a livestock feed. The seed, with its by-
products, oil and oil meal, have great commercial possibilities as a
food and for industrial purposes. In spite of the extensive investi-
gations that have been conducted, the work of developing this versa-
tile plant to its fullest possibilities is still in its infancy. While much
has been done in determining the genetic relations of many seed and
plant characters, the plant breeder has many problems of a complex
nature ahead in the development of new and better varieties for the
various purposes for which the crop is now being used.
HISTORY OF THE SOYBEAN
The early history of the soybean is lost in obscurity. Ancient Chinese
literature, however, reveals that it was extensively cultivated and
highly valued as a food centuries before written records were kept.
It was one of the grains planted by Hou Tsi, a god of agriculture.
The first record of the plant is contained in a materia medica de-
scribing the plants of China, written by Emperor Sheng Nung in 2838
B. C. The crop is repeatedly mentioned in later records, and it was
considered the most important cultivated legume and one of the five
sacred grains essential to the existence of Chinese civilization. Seed
of the plant was sown yearly with great ceremony by the Emperors of
China, and poets extolled its virtues. The records of methods of
culture, varieties for different purposes, and numerous uses indicate
that the soybean was perhaps one of the oldest crops grown
by man.
Botanically the soybean usually has been referred to in literature
as Glycine hispida (Moench) Maxim. In an extensive botanical
1 The authors are greatly indebted to C. M. Woodworth and L. F. Williams, of the Illinois Agricul-
tural Experiment Station, tor their cooperation and suggestions in the preparation of this article.
1154
SOYBEANS
1155
study Piper (fig. 1) came to the conclusion that the soybean must be
named Soja max (L.) Piper. Other botanists, however, consider
Glycine javanica L. the type species of Glycine and call the soybean
Glycine max (L.) Merrill.
The cultivated soybean is thought by many investigators to have
been derived from Glycine ussuriensis Regel and Maack, which
grows wild throughout much of
eastern Asia. This species is
prostrate in habit of growth,
has long fine twining stems,
small narrow leaves, appressed
haii-s, purple flowers, small com-
pressed pods, and small oblong
seeds of a sooty-black color.
Karasawa (9)2, on the basis of
genetic data, believes the cul-
tivated soybean might have been
derived from this wild species
through the qualitative and
quantitative changes due to
gene mutation, unaccompanied
by any change in chromosomes.
A plant with characters be-
tween the wild and the culti-
vated species has been described
by Skvortzov (S3) as G. gracilis
Skvortzov.
Europeans knew of soybeans
in the seventeenth century, and
they were tried in Germany,
England, France, and Hungary
but did not become commer-
cially established in any part
of Europe until in recent years.
The first mention of the soybean in American literature was in 1804,
when James Mease wrote: "The soybean is adapted to Pennsylvania
and should be cultivated." In 1889 W. P. Brooks, of the Massa-
chusetts Agricultural Experiment Station, brought a number of
varieties from Japan, and in 1890 C. C. Georgeson, of the Kansas
station, secured three lots from the same country. Undoubtedly
other early importations of seed from Asia were obtained through
missionaries, but no definite records have been found. Since 1890
most of our agricultural experiment stations have experimented with
soybeans and many bulletins have been published dealing wholly or
partly with the crop.
In 1898 the Department started to introduce large numbers of soy-
beans. Previous to this there were not more than eight varieties,
with limited adaptation to soil and climate, grown in the United States.3
Since that time the acreage of soybeans in the United States has in-
'Italic numbers in parentheses refer to Selected References on the Genetics of the Soybean, p. 1181.
3The eight varieties of soybeans crown in the Lnited States were Ito San, Mammoth Yellow, Butterball
Buckshot, Kingston, Guelph or Medium Green, Eda, and Ogemaw.
figure I. — The late Charles Vancouver
Piper, agronomist, United States Depart-
ment of Agriculture, 1902-26. Pioneer in
the introduction and development of soy-
bean varieties for United States conditions.
1156 YEARBOOK, 1937
creased more than a hundredfold — from less than 50,000 acres in 1907
to nearly 5,500,000 acres in 1935. The increase in acreage and
production in this country has been closely correlated with the intro-
duction of varieties from the Orient and their development
through selection.
WORLD DISTRIBUTION AND PRODUCTION
The soybean is grown to a greater extent in Manchuria, often
called "The Land of Beans", than in any other country in the world
(fig. 2). It occupies about 25 percent of the total cultivated area
and is the cash crop of the Manchurian farmer (fig. 3). Chosen and
Japan are large producers, and south of China the soybean is culti-
vated more or less in the Philippines, Siam, Cochin China, India, and
the East Indies.
In the central part of the Union of Soviet Socialist Republics the
districts of the Don and the southwest are said to be especially suited
to the culture of this crop. In Czechoslovakia, in 1935, commercial
beans were produced on a small scale. Rumania has also succeeded
in growing soybeans of high quality, and the production of seed is
rapidly increasing. In other parts of the world, particularly Germany,
England, South Africa, British East Africa, Algeria, Egypt, New South
Wales, and New Zealand, soybeans have been tried or are being grown
in a small way.
In the Western Hemisphere the production of soybeans is concen-
trated chiefly in the Corn Belt region of the United States. In 1920,
ONE of the most striking agricultural developments in the United
States in recent times is the rapid rise of the soybean. In 1907
there were 50,000 acres; in 1935, nearly 5,500,000. In 1920,
seed production was 3,000,000 bushels; in 1935, about 40,000,000.
Remarkable progress has been made in the last few years in develop-
ing food and industrial uses. Soybean breeding to meet varied
cultural, food, and industrial needs is being conducted by the
United States Department of Agriculture and by experiment
stations in 32 States, and more than 10,000 introductions have
been made for study and experiment. In spite of extensive inves-
tigations, the work of developing this versatile plant to its fullest
possibilities is still in its infancy. But though the plant breeder
has many problems of a complex nature ahead, there appears to
be no reason why it should not be possible, by selection and hybridi-
zation, to develop varieties that possess all, or nearly all, the im-
portant characters desired by oil processors and by manufacturers
of food and industrial products.
SOYBEANS
1157
14 States produced 3,000,000 bushels of seed, the leading States being
North Carolina, Virginia, Alabama, Missouri, and Kentucky — North
Carolina producing about 55 percent of the total. By 1931, seed pro-
duction had increased to nearly 15,500,000 bushels, with Illinois,
Indiana, North Carolina, and Missouri leading. In 1935, about
40,000,000 bushels of seed were produced, of which about 37,500,000
bushels (92 percent) were harvested in Illinois, Indiana, Iowa, Mis-
souri, and Ohio, the first three States producing about 87 percent of
the total. In Canada, production is confined chiefly to the Province
Figure 2. — Storage yard of a Chinese grain merchant near Knngchuling, Manchuria.
More than 80 osier bins, each holding four carloads of soybeans, were in this yard.
of Ontario, where about 15,000 acres are planted to this crop. In
other parts of the Western Hemisphere the acreage grown in any
country is small.
Table 1 shows the increase in production of soybeans over an 11-
year period, 1924-25 to 1935-36 inclusive, in the principal producing
countries of the world.
Table 1. — Increase in production of soybeans over an 11 -year period,
1924^25 to 1935-36, inclusive, in the principal producing countries
of the world '
Country
Production in—
1924-25
) 935-36
Manchuria _
Bushels
92, 667, 000
18, 723, 000
15,367,000
5, 190, 000
3, 536, 000
Bushels
140,444,000
"21,961,000
" 13,307,000
39, 637, OflO
'6,676.000
Chosen.. _
United States
Netherland India
' From the following publication: U. S. Dept. Agr., Agricultural Statistics 1936.
1 1934-35. ' 1933-34 (decrease).
1158
YEARBOOK, 1937
Fifiiirv 3.— The Manchnrian farmer still harvests (A), threshes (B), and cleans
(C) soybeans by hand methods inherited from his ancestors, whereas in the
United States (D) modern machine methods are used.
SOYBEANS
1159
UTILIZATION OF THE SOYBEAN
In the Orient the soybean is grown principally for the seed, which for
centuries has been utilized in the preparation of a great variety of
fresh, fermented, and dried food products indispensable in the diet of
oriental people. Large quantities of beans are also crushed for oil,
which is used for food and numerous industrial purposes; and the
resulting cake or meal
(fig. 4) is utilized chief-
ly as a fertilizer and to
a small extent as feed
for animals. Europe-
an oil mills have for
many years imported
considerable quanti-
ties of soybeans from
Manchuria (fig. 5) for
crushing for oil and oil
meal.
The soybean is used
in the United States
primarily for forage
purposes, being ^either
preserved as hay or
silage or cut and fed
green as soilage. It is
also pastured exten-
sively with hogs and
sheep, and is used to
some extent as a green
manure or cover crop.
For many years the
increasing supply of
seed was matched by
a steady demand for
planting the expand-
ing acreage and for use
as a stock feed, but
eventually other out-
lets had to be found.
About 1920 the possi-
bilities in home-grown
soybeans attracted the attention of oil mills, and by 1929 they began
to be a potent factor in the production of the crop for commercial
purposes. In 1926 slightly more than 2,.r)00,()00 pounds of oil were
produced in the United States, while more than 200,(100,000 pounds
were obtained from the 1935 crop.
Remarkable progress has been made in the last few years in develop-
ing food and industrial uses for the soybean, the oil, and meal. At
present about 45 oil mills, including a few cottonseed oil mills, are
crushing soybeans; more than 40 concerns are manufacturing soybean
food products and soybean flour; and more than 75 factories are
lipurr 1. Millions of soybean oil cakes are stored in
warehouses in Manrhuria awaiting shipment to Japan,
Chosen, China, and the Kast Indies, where they are used
for fertilizing purposes and for cattle feed.
1160
YEARBOOK, 193 7
turning out various industrial products made from soybeans. Soy-
bean oil has become an important product in many industries, in
addition to the use of the meal in livestock feeds, considerable quanti-
ties are utilized in the manufacture of foods and industrial products.
The high nutritional value of the soybean, known for many centuries
in oriental countries, is becoming quite generally recognized in the
United States. Many food concerns in various parts of the country
are manufacturing numerous products wholly or in part from the
soybean.
The following outline shows the diversity of uses to which the
different products of the soybean arc put:
SOYBEAN UTILIZATION
I Fuel.
Furfural.
Hay.
Silage.
Soilage.
'Meal.
Oil..
Green bean.
Dried bean.
/Celluloid substitutes.
Core binder.
Feeds
Fertilizer.
Glue,
i Cattle.
Dogs.
Fish.
Hogs.
Poultry.
Rabbits.
Sheep.
Human food
Plasties.
.Water paints.
Candles.
Celluloid.
Core oil.
Disinfectant.
Electrical insulation.
Enamels.
Foodproducls
Fuel.
Glycerin.
Insecticides.
Lecithin
Lighting.
Linoleum.
Lubricant.
Oilcloth.
Paints.
Printing ink.
Rubber substitutes.
Soaps
Varnishes.
Waterproof for cement.
Waterproof goods.
Canned.
Frosted.
Green vegetable.
Salad.
Baked.
Boiled.
Breakfast foods.
Feeds
(Beer brewing.
Flour. (See Dried bean.)
Seasoning powders.
Soy sauce.
Vegetable milk.
I Butter substitutes.
Cooking oils.
Lard substitutes.
Salad oils.
Medicinal oil.
Candies.
Chocolate.
Cocoa.
Emulsifler.
Margarine.
Medicines.
Textile dyeing.
(Hard.
.^Liquid.
ISoft.
Cattle.
Hogs.
Poultry.
Sheep.
Flour ■
{Candied.
Coffee substitute.
Salted.
Soy sauce. fPaints.
Sprouls.
Vegetable
milk
Casein .
Condensed.
Paper size.
Textile dressing.
Waterproofing.
Baked products.
Breakfast foods.
Candies.
Chocolate.
Diabetic foods.
Health drinks.
Ice-creara cones.
Ice-cream powder.
Infant foods.
Macaroni products.
.Meat products, filler.
[Canned.
Dried.
Curd { Fermented.
Foods. Fresh.
Powder. ISmoked.
SOYBEANS
1161
Figure 5. — Coolies loading soybeans on a freighter for shipment lo the
oil mills of Europe.
IMPROVEMENT OF SOYBEAN VARIETIES
Soybean breeding is being conducted in tbe United States, Japan,
Manchuria, China, India, Chosen, and tbe Union of Soviet Socialist
Republics, and to some extent in a few European countries. As
with other crops, tbe chief objective has been increased yield under
local conditions. Within tbe last few years, however, with increased
utilization of the soybean for industrial and food purposes, attention
has also been given by plant breeders to the oil and protein content,
the nutritive value, and the quality of beans.
In the United States, more than 50 percent of the acreage devoted
to soybeans is used for forage and pasture; breeding work, therefore,
has tended largely toward tbe development of varieties for hay, silage,
and pasture. The development of such varieties as Virginia, Laredo,
Otootan, Wisconsin Black, Mancbu, Wilson-Five, Kingwa, Peking,
and Ebony by selection from introductions has been the principal
factor in the increased use and acreage.
Beginning with 1929, the use of soybean seed by oil mills has led to
a demand for yellow-seeded varieties of high oil content. Agrono-
mists and plant breeders have attempted to meet this demand by
making large numbers of selections from foreign introductions and
locally grown varieties and by analyzing these for oil content. This
bas brought about the development of several superior oil varieties
and has resulted in a large increase in production of beans for milling
purposes. The most popular of these varieties are lllini, Dunfield,
Mukden, Mandell, Scioto, Mansoy, Mancbu, Mamredo, Delsta, and
Mandarin. Results of analyses with more than 1,000 selections and
varieties have shown a range of from 12 to 26 percent in oil content.
From studies of the oil content of varieties grown in a given locality,
138904°— 37 74
1162
YEARBOOK, 1937
it seems possible, from the breeding standpoint, to produce varieties
high or low in oil, at least within the known ranges of variation
exhibited by common varieties.4
Quality, which may include several characters, the most important
of which are the iodine number and the lecithin value, is the chief
factor in the use of soybean oil. The drying property of an oil is
Figure 6. — Prize winners. Mancfaarian farmers are awarded certificates and prizes
for producing high-quality soybeans.
measured by the iodine number, that of linseed being about 180. In
a large number of tests with varieties and selections of soybeans, the
iodine number ranged from 118 to 141. The iodine number of the
wild soybean was found to be 155. To give soybean oil a bettor
drying quality for paint purposes, its number must be raised. On the
other hand, it is stated that oil with a low iodine number is more
suitable for food purposes. Lecithin, a phosphatic compound, of
which egg yolk was the chief source of supply, is now being extracted
from soybean oil on a commercial scale. It is used extensively in the
baking and confectionery trades, and also in textile and leather indus-
tries. Varietal studies show a range of 1% to 3 percent, according to
variety. The development of varieties high in lecithin and high and
low in iodine number offers a most promising problem to the plant
breeder. The best procedure in breeding for quantity and quality
'The Agricultural Experiment Station of the South Manchuria Railway at Kungchuling, Manchuria,
has conducted experiments for several years toward the selection of varieties for high oil content. One
variety, the Kungchuling, with seed uniform in size and shape and an oil content of more than 20 percent,
has been widely distributed. To encourage the growing of this variety in regions to which it has been
found adapted, the Experiment Station holds an annual soybean fair at which prizes are given to the farmers
having the highest uuality of seed (fig. 6).
SOYBEANS 1163
of oil in the soybean is without doubt to analyze adapted varieties
and then to isolate the best line from the best variety.
The development of new industrial uses for protein from the soybean
and the value of this constituent in foods and feeds has led investi-
gators to give more attention to varietal differences in the amount and
quality of protein. Extensive analytical tests show a range of from 28
to 56 percent of protein (moisture-free basis), depending on variety
and locality. Investigations of the nutritive value of soybean protein
have shown that it contains all the essential amino acids. Studies by
the Bureau of Chemistry and Soils of the United States Department
of Agriculture with several standard varieties show a wide range in
percentage of three amino acids — cystine, tryptophane, and tyrosine —
which indicates the possibility of developing varieties of high nutritive
value for animal feeds and human foods.
In the Orient, soybean foods to a very considerable extent supply the
protein that is furnished largely by meats in the diet of western people.
Oriental varieties of soybeans are distinguished not only according to
seed and plant characters but also according to use, as for bean curd,
bean sprouts, confections, and other food products. Increased recog-
nition of the nutritional value of the soybean in the United States has
created a demand for varieties more suitable for this purpose, since the
varieties generally grown for commercial uses are not desirable for food.
The principal drawbacks to the use of dried beans have been the length
of time necessary for cooking and the flavor. Experiments with a large
number of selections and varieties used in the Orient showed consid-
erable variation. Some were of excellent flavor and became soft in
less than 2 hours of cooking, while others remained hard and had little
flavor or a pronounced bean flavor. Several of the most promising have
been tested in various sections and the Easycook, Bansei, Rokusun,
Jogun, Chusei, and Sousei are now in the hands of growers and seeds-
men. Experiments by commercial firms have shown that these varie-
ties are superior to commercial varieties for the manufacture of food
products, such as bean flour, roasted beans, bean milk, and bean curd.
In Japan, certain varieties of soybeans were found that were used
solely as green shelled beans. Ranging in maturity from 75 to 170
days, many of these introductions, and selections from them, have
been found especially promising for various sections in the United
States. The vegetable soybean offers an excellent food of high nutri-
tional value, especially in the fall when other green beans are lacking
and in sections where the Mexican bean beetle prohibits the growing
of garden beans. As a result of selection, cooking tests, and adaptation
studies, eight green vegetable varieties — Hahto, Kura, Kanro, Hok-
kaido, Higan, Chusei, Sousei, and Jogun — have been introduced in
various sections of the country.
Although the major objective of soybean breeding has been to
increase acreage yields, increasing utilization for food and industrial
purposes demands improvement in quality as well as yield. With the
vast number of introductions now under test by the Department and
State experiment stations, there appears to be no reason why it should
not be possible, by selection and hybridization, to develop varieties
that possess all, or nearly all, the important characters desired by oil
processors and by manufacturers of food and industrial products.
1164 YEARBOOK, 1937
ADAPTATION
The soybean seems to be peculiarly sensitive to changes of soil and
climate. Differences in behavior of the same pure-line variety in
different localities are often very striking, so much so that it is often
difficult to believe the variety is the same. Obviously, this adaptation
explains why practically every locality in the soybean regions of the
Orient has its own local varieties. Of the many varieties introduced
into the United States, the same variety has rarely been secured a
second time unless it was obtained from the same locality. In the
Orient, limited areas appear to have varieties adapted to their own soil
and climatic conditions. For the most part, Japanese varieties are
unsuited to Manchuria and Chosen (Korea), and on the other hand,
few Manchurian and Korean varieties are suited to Japan. Very
few Korean varieties are adapted to the soil and climate of Man-
churia. In these countries centuries of experience, aided by natural
crossing and natural selection, have brought about the development
of varieties adapted to special purposes. In China, Japan, Man-
churia, and Chosen varieties are found especially suited for bean curd,
bean milk, bean sprouts, green vegetable beans, bean flour, bean con-
fections, oil and oil meal, and fermented products. Different regions
in these countries have their own different varieties for these purposes.
One of the outstanding results of soybean improvement work in the
United States has been the realization of the importance of varietal
adaptation. Early investigators noted that introductions from vari-
ous localities in the Orient differed widely in their adaptation to various
regions or localities in this country. This led to the conclusion that
by introduction and local selection strains adapted to all localities,
conditions, and purposes could be developed. With the increase in
the number of introductions and the development of new varieties
from these for a greater range of soil and climatic conditions, the
acreage in commercial plantings has increased.
In many regions of the United States adaptation experiments com-
paring standard varieties with newly developed sorts or new intro-
ductions indicate that the new types are better adapted than the
commonly grown varieties, and it seems likely that varieties for dif-
ferent uses that suit requirements in nearly all our farming regions
will be found. At present about 100 named varieties (see appendix,
table 4) are generally grown or are being increased for greater dis-
tribution in this country. Although it would be highly desirable to
limit the number of varieties in the trade, unfortunately each region
must have locally adapted varieties suitable for different purposes
in order to obtain the best results.
METHODS IN BREEDLNG
The soybean is normally a self-fertilized plant, the flowers being per-
fect, producing both pollen grains and ovules. The flowers are com-
pletely self-fertile, as shown by experiments carried on by Piper and
Morse (30) at the Arlington Experiment Farm, Arlington, Va. (near
Washington, D. C), in. 1909. Screened or bagged plants set pods and
seeds as perfectly as plants in the open. Similar experiments by
Woodhouse and Taylor (54) in India gave identical results. As
SOYBEANS 1165
pollination occurs about as soon as the flower opens or a little before,
there is little opportunity for cross-pollination to take place. How-
ever, natural crossing does occur. Since the plant is self-fertilized,
the same general principles of breeding that apply to other self-ferti-
lized crops may be applied to the improvement of the soybean.
Selection within self-fertilized plants is effective in purifying exist-
ing strains and makes some improvement possible, but variations are
essential for any great improvement within a crop, and the only
practical means the plant breeder has of inducing variations is by
hybridization. By this method he may combine desirable characters
from different varieties in one type and obtain plants that express a
character to a greater or lesser extent than it was expressed in either
parent. As with other crops, the major problem in the improvement
of the soybean is to bring together into one type all the characters
that are considered desirable for a certain set of conditions. From
this standpoint, hybridization holds much promise for the develop-
ment of special varieties of soybeans. This involves close study of
wild and domestic species, varieties, and strains and their reactions to
environment, as well as quantitative and qualitative analysis of oil,
protein, and other constituents of the seed.
After varieties are selected or developed the grower faces the prob-
lem of maintaining them as pure strains. Commercial varieties of
soybeans are in general relatively pure because the plant is self-
fertilized. However, in a field of a single variety one often finds more
or less offtype plants. Such mixtures may be brought about by
careless methods of planting and threshing, by natural crossing, and
by mutation. No natural crossing will result if mechanical mixtures
are avoided. Mutations rarely occxir and therefore are not an impor-
tant factor. A variety can be kept relatively pure by careful methods
of planting and threshing and by roguing out offtype plants.
Natural and Artificial Crossing
Previous to 1907 it was quite generally assumed that natural
crossing in the soybean did not occur. In that year oddly colored
seeds were noted in the variety rows and plots at the Arlington Experi-
ment Farm, and were selected by Piper and Morse (80). The progeny
of these seeds in 1908 showed segregation for various seed and plant
characters. In that year more than 100 single plants of supposed
hybrid' origin were selected and most of these broke up in the following
year in simple Mendelian proportions, indicating that they were
natural hybrids. It is often easy to detect hybrids by the peculiar
coloration of the seeds (fig. 7). Among the more striking colors are
yellow or green with narrow streaks or bands of black or brown
beginning usually at the hilum and extending over half or more of the
seed, or mainly centered about the hilum. Hybrid plants are also
often distinguished by the unusual form of the pods near the tips
of the branches. They are more swollen and the seeds are more crowd-
ed than normal; the pods are often thinner walled and much less
pubescent, sometimes being nearly smooth.
Natural crossing in soybeans has been studied to some extent by
various investigators and it is quite generally agreed that a limited
amount does occur, but that it is much less than 1 percent.
1166
YEARBOOK, 1937
m
•
^P ^^
Figure 7. — Seeds of a natural soybean hybrid showing peculiar
types of coloration.
SOYBEANS 1167
Even this small amount of natural crossing undoubtedly is respon-
sible for many of the mixtures now occurring in our standard varieties.
The crossing is made possible by the mechanical mixing of seed
through careless methods of planting and harvesting. After finishing
with one variety, the planters or harvesters are not thoroughly cleaned
before starting on another, so that the two varieties are mixed in the
same field. An excellent ilhistration of this is afforded by the Mam-
moth Yellow variety now produced in eastern North Carolina. For
many years this was the only variety grown in that section and it
remained pure. As other varieties were introduced, the Mammoth
Yellow seed became more or less mixed and it is now difficult to find
fields without offtypes.
Natural crossing in soybeans is undoubtedly brought about by
small insects. Thrips have been observed to be very common in the
soybean flowers at the Arlington Experiment Farm. Bees and other
insects have also been observed working on soybean flowers. Studies
by many investigators at various places indicate that soybean plants
growing in contact with one another are more likely to be crossed
than plants separated by a few feet.
Because the flower is very small and easily injured, the work of
making artificial crosses with the soybean is a difficult and tedious
operation. Under field conditions at the Arlington Experiment Farm,
Piper and Morse (SI ) made successful crosses in aboiit 20 percent of the
operations. In the greenhouse, where it is difficult to secure normal
behavior in the soybean plant in winter, no success has thus far attend-
ed efforts to produce hybrids. Under winter conditions, the plants are
small and bear few flowers, which do not develop and open normally
and which apparently become fertilized in the very early bud stage.
Woodworth (68), in crossing studies, found that soybean crosses can
be made in the greenhouse as well as in the field provided artificial
light is used. Light from 500-watt bulbs was used in the early stages
of plant growth to induce good vegetative development, and then the
fight was shut off to induce flowering. The percentage of successful
crosses is said to compare favorably with that ordinarily obtained
under field conditions.
Crossing the flowers in the afternoon from 3 to 7 o'clock has given
the best results, and it also has 'been found best to emasculate and
pollinate a flower the same afternoon. Experience has shown that
emasculation is the most difficult part of the operation and must be
performed before the soybean flower has fully opened. All of the
flower buds should be removed from the raceme except those to be
crossed, and in these the purple or white of the corolla must have
appeared above the calyx. At this stage, the 10 anthers surrounding
the stigma (fig. 8) are immature and may easily be removed without
bursting the pollen sacs. After emasculation, pollination is a rela-
tively simple process, the pollen being applied to the stigma at
once. In collecting the pollen for crossing, it is advisable to select
well-developed flowers just before they open or fresh-looking flowers
that have just opened. After the pollen has been applied, the
raceme should be enclosed in a small paper or cloth bag, or a
leaf may be pinned around it to protect the parts from excessive
evaporation.
1168
YEARBOOK, 1937
Figure 8. — Soybean flower and parts enlarged: A, Front view; B, side view; C, parts
of the corolla (a, standard; b, wing; c, one of the keel petals); D, stamens; E,
pistil.
Mutations
The origin of new varieties of soybeans without hybridization has
apparently occurred in several instances that have come under the
observation of investigators. Piper and Morse (30) cite a case in
which a brown-seeded type, the Trenton, arose as a mutation
from a yellow-seeded variety, the Mammoth Yellow. Grown side
by side at the Arlington Experiment Farm, these varieties were
indistinguishable by any character other than the seed color. Wood-
worth (63) explains this by assuming that the gene designated as
ii, carried by the Mammoth Yellow variety, mutated to the gene
designated as i, and that this permitted the brown pigment of the
Mammoth Yellow hilum to extend over the whole seed coat to
produce a brown bean.
A more recent mutation gave rise to the Avoyelles variety. This
variety with medium-sized black seed was selected in Louisiana from
a field of Otootan, a small black-seeded type, and it gave uniform
progeny that in many characters is superior to Otootan. Stewart
and Wentz (36) discovered a recessive glabrous type which they
designated by the symbol p2 and assumed that it arose as a mutation.
Woodworth (63) notes the following mutations that have come under
his observation: Dark to light pod, normal plant size to dwarf, normal
green plant to variegated, and black hilum to brown hilum. In
addition to these he has noted a few mutations in vegetative cells
that resulted in "chimeras" of various kinds.
SOYBEANS 1169
Hybrid Vigor
The phenomenon of heterosis, or hybrid vigor, in soybeans was
first reported by Wentz and Stewart (50), who found in the first-
generation hybrid of some crosses considerable increases in height of
plant over the average of the parents. Still greater evidences of
hybrid vigor were shown by the hybrids in yield of seed, the per-
centage increases over the parents ranging from 59.58 to 394.37.
Studies on hybrid vigor involving a greater number of crosses and
more characters were made by Veatch (46). In 16 crosses the char-
acters in which the hybrids exceeded, on the average, even the better
parents, and therefore the characters in which hybrid vigor was
shown, were the following: Number of pods per plant, plant weight,
plant height, total stems and branch length, number of nodes, days
from planting to flowering, seed weight or yield, and number of seed.
Considerable variation, however, was found among the hybrids in
the extent of hybrid vigor. Although the average of all the hybrids
was higher in all characters studied than the average of all the parents,
the average of all the better parents exceeded the average of the
hybrids in average seed weight, number of seeds per pod, ratio of
straw to grain, and average internodo length.
Nagai (22) also reports that the individual of the first hybrid
progeny is extremely prolific in comparison with its parents. In a
cross between the Akazaya (seed yield per plant 34.18 grams) and
the Hashikawa Yellow (seed yield per plant 34.18 grams) varieties,
the first-generation hybrid yielded 52.97 grams and the first generation
of the reciprocal cross 54.84 grams. In two other crosses similar
evidences of hybrid vigor were shown in yield of seed over the parents.
The problem of utilizing this hybrid vigor for increased production is
rather complicated, and in order to make any definite progress more
extensive investigations are essential.
INHERITANCE STUDIES AND CYTOLOGY5
The many strains differing widely in plant and seed characters and
the almost complete self-fertility of the soybean make it an excellent
plant for genetic study. The tediousness and difficulty of artificial
crossing xmdoubtedly have been the chief reasons why more extensive
genetic analysis of the plant has not been undertaken. Woodworth
(63) and Nagai (22) have perhaps made the most substantial contri-
butions. Considerable information has been collected on the be-
havior of progeny of natural and artificial hybrids, the most important
features of which are presented herein under discussions of various
plant and seed characters.
Plant Characters
Flower, stem, pubescence, and foliage
Soybean flowers occur in two colors, purple and white. While
variations in intensity and grade of color occur in the purple-flowered
varieties, no attempt has been made to differentiate them except
by Nagai (22) and Takahashi and Fukuyama (42). Skvortzov (S3)
■'This section is written primarily for students or others professionally interested in breeding or genetics.
1170 YEARBOOK, 1937
mentions a wild species of soybean with yellow flowers in Manchuria.
This is perhaps an error, as there has been no hint of yellow flowers
in the 10,000 or more introductions of cultivated and wild varieties
and strains from all parts of the world, studied by the Department
and numerous State experiment stations. In crosses, Woodworth
(58) found purple (W) dominant to white (id), with a simple ratio of
3 purple to 1 white in F2. A dihybrid ratio of 9 purple, 3 purplish red,
and 4 white was obtained in an F2 generation by Takahashi and
Fukuyama (42). Nagai (22) reports purple dominant to white in a
simple segregation ratio, or the segregations may be observed in three
colors, purple, purplish blue, and white in a 9.3 :4 ratio, the purple
in the case evidently being determined by two factors. Piper and
Morse (31), in both artificial and natural hybridization, found flower
color to separate in simple Mendelian ratio, the purple flowers being
dominant.
The stems of soybean seedlings are either purple or green, the purple
color being most abundant just below the cotyledons. Purple-stemmed
plants bear purple flowers and green-stemmed plants bear white
flowers. In extensive tests at the Arlington Experiment Farm no
exception was found to this relationship. Woodworth (63) reports
similar results and states that the same gene probably is responsible
for both characters. Stem color is undoubtedly a reliable indication
of the flower color to be shown later by the plant.
According to Nagai (22), many Japanese varieties of edible soy-
beans have a special character known as fasciation (fig. 9). In crosses
of such plants with normal plants, Woodworth (63), Takagi (39),
and Nagai (£%) found fasciation to be recessive, and in F2 a ratio of
3 normal to 1 fasciated was obtained.
Nearly all varieties of soybeans are pubescent, that is, the stems,
leaves, and pods are covered with fine tawny (brown) or gray hairs.
In most cases there is no difficulty in distinguishing the two colors,
but in some instances in selection from natural hybrids the pubes-
cence color often is intermediate between gray and tawny, and some-
times both colors appear on the same plant. With artificial hybrids,
the colors of pubescence have behaved in the same way as with
natural hybrids. Tawny pubescence (T) is dominant to gray (t),
and in F2 a simple ratio of 3: 1 is obtained.
Several yellow-seeded Japanese varieties, such as the Hadaka and
Mizukuguri, are entirely glabrous, that is, lack pubescence or hairi-
ness. These glabrous varieties of early, medium, and late maturity
have been found by Japanese investigators to be highly resistant to
attack by the pod borer (Laspeyresia glycinivorella Mats.), while pubes-
cent varieties are highly susceptible to injury from this pest. In the
United States, Johnson and Hollowell (8) found glabrous varieties
subject to considerable injury from the leafhopper (Empoasca fabae
(Harris)), while pubescent varieties were immune. According to
Woodworth (63), glabrous soybeans fall into two distinct types. When
crossed with pubescent varieties, one type behaves as a dominant
while the other type behaves as a recessive. In each case the ratio
is 3:1, indicating that a single factor pair is involved. Nagai and
Saito (23) discovered the dominant type and Stewart and Wentz (36')
the recessive. Glabrous soybean plants are smaller, shorter, and
SOYBEANS
nil
Figure 9. — A, Stems anil pods of fasciated soybean plants; B, determinate pod-
bearing type; C, indeterminate pod-bearing type.
1172 YEARBOOK, 1937
yield less than most pubescent plants, according to Nagai and Saito
{28) and Owen {25). Nagai {22) had one case in which strictly gla-
brous plants occurred in the F3 generation in a cross of pubescent
parents. The occurrence of this glabrous progeny was attributed to
mutation.
In a study of the differences in amount of pubescence in American
and Indian varieties, Woodhouse and Taylor {54) noted that the
leaves of the Bengal "types I-V" differ from those of the Nepali
"type VI" and the American varieties in being covered with soft
upright hairs on their upper surfaces, whereas, the upper surfaces of
the latter are covered with closely apprcssed hairs. In a cross be-
tween the cultivated and the wild soybean {Glycine ussvriensis) ,
Karasawa {9) found apprcssed pubescence in the wild soybean domi-
nant to erect in the cultivated soybean, the segregation occurring in
accordance with the monohybrid ratio.
A wide variation occurs in the leaves of soybeans, involving shape,
size, color, and degree of persistence. These characters merge by
iusensible degrees so that they are useful in differentiating varieties
only in extreme cases. In shape- the leaflets in some cases are ovate-
lanceolate or almost linear; in others, nearly orbicular. In color they
are usually a pale green but in some varieties dark green. In nearly
all varieties the leaves commence io turn yellow as the pods begin
to ripen and commonly all have fallen when the pods are mature.
A few varieties, however, like the Medium Green, Old Dominion,
Kingwa, and Wisconsin Black, retain, their leaves until all or nearly
all of the pods are mature. It has been quite generally observed
that varieties with yellow cotyledons have leaves that turn yellow
as they mature, whereas some varieties with green cotyledons have
leaves that remain green and persist until maturity. It is believed
that the retention of green in the leaves is associated or tied up
with the green cotyledon color and is separate and distinct from
the simple retention of leaves by the plant. Additional leaflets occur
not uncommonly in several varieties. This seems to be especially
true with the linear-leaved form and with several early green-
vegetable varieties from Japan, which frequently have leaves with
four or five leaflets.
According to Nagai {22) there are two kinds of yellow leaves. One
is greenish yellow from the beginning of growth and has little chloro-
phyll. The other has a normal or nearly normal amount of chloro-
phyll when young, but the leaves turn yellow as the plant grows. It
was found that when either kind is crossed with a green-leaved vari-
ety, yellow leaves are recessive to green leaves, segregating in a 3:1
ratio in the former and in a 15:1 ratio in the latter.
Takahashi and Fukuyama {42), in studies of hybrids between nor-
mal and narrow-leaflet forms, found the F} generation to be interme-
diate, and in the F2 a ratio of 1:2:1 was obtained. Woodworth
{68) found essentially similar results in crosses between normal and
narrow-leaflet forms, except that the broad shape was partially
dominant and the F2 generation was made up of two main forms,
broad and narrow, in a 3:1 ratio. There were a few F2 plants,
however, that seemed to be intermediate in leaflet shape between the
two parents.
SOYBEANS 1173
In a cross made by Takahashi and Fukuyama (42) between a vari-
ety showing 73 percent of the compound leaves with extra leaflets
and a normal variety the hybrid showed 52 percent of the compound
leaves -with extra, leaflets. In the F2, however, a ratio of 3 plants
with extra leaflets to 1 normal plant was obtained.
Woodworth (68) found in the F3 generation of a hybrid a single
plant with variegated leaves. As neither parent possessed this char-
acter, it was supposed that the variegation arose as a mutation. In
crosses with normal and variegated plants, variegation proved to be
recessive. While the deviation from the expected 3 : 1 ratio was rather
large, it was believed that variegation (i\) is a simple recessive to nor-
mal in inheritance. Takagi (39) has reported a type with greenish-
yellow leaves that appeared in one-sixteenth of the F2 progeny of a
cross between two normal, green-leaved plants.
Height of Plant and Maturity-
Two cases of inheritance of size in the soybean plant have been
reported in which definite segregation in plant height was observed.
Woodworth (58) describes a natural hybrid that segregated in the
ratio of 3 tall-growing plants to 1 short, stocky, early-maturing plant.
Stewart (34) reports a dwarf form that behaved in inheritance as a
simple recessive to the normal.
In soybeans there is a complete series of varieties ranging from very
early (about 75 days) to very late (200 days or more). With very
few exceptions earliness is correlated with size, the tallest varieties
being latest. The maturity character usually has a complicated mode
of inheritance because it is determined by numerous genes. Wood-
worth (58), however, describes a progeny of plants that segregated
for two plant sizes, tall and short, in a 3:1 ratio. Coupled with plant
size was a difference in maturity. The tall variety matured usually
about 2 weeks later than the short variety. In this case, late maturity
was dominant. Studies by Veatch (46) tended to confirm this, but
Owen (25) found the Ft of crosses between early and late varieties to
resemble the early in time of maturity more than the late, and in F2
the range in maturity due to segregation covered the entire parental
* Pod-Bearing Habit and Pod Characters
In a classification of soybean varieties Etheridge, Helm, and King
(5) placed 100 or more varieties into classes with respect to pod-bearing
habit as determinate and indeterminate (fig. 9). The determinate
class has a dense array of pods on the central stem, terminating in a
blunt apex, with a thin dispersal on the lateral branches. The
indeterminate class has a sparse and comparatively even distribution
of pods over all branches and stems, a diminishing frequency toward
the top of the central stem being notable. Woodworth (63) obtained
a segregation for pod-bearing habit of 69 indeterminate plants to 19
determinate plants, a single-factor difference appearing to be involved.
The pods of the soybean exhibit a wide variation in color, ranging
from very light straw yellow through numerous shades of gray and
brown to black. As yet very little work has been done in classifying
varieties as to pod color or in studying pod-color inheritance ; however,
pods usually have been divided into two groups — dark pods, which are
1174 YEARBOOK, 1937
mostly black or nearly so, and light pods, ranging from a very light
tan to light brown. In inheritance studies, Woodworth (58) and
Piper and Morse (31) found dark pods dominant to ligbt and in the
F2 obtained a ratio of 3 dark to 1 light.
While the pods in most varieties of soybeans are distinctly com-
pressed, some are cylindric, and all possible intermediate forms exist.
Nagai (22) places pods into two general classes, flat and bulky. In
crosses he found the segregation of these two characters quite distinct,
the flat (compressed) being dominant to the bulky (cylindric).
Soybean pods in most varieties contain two to three seeds, rarely
one or four. The linear-leaf soybeans from Manchuria possess a
large percentage of four-seeded pods, although a few five-seeded pods
have been found. Without doubt, seed number per pod is a heredi-
tary character, although in some instances it is quite unstable, depend-
ing upon method of culture, season, and fertility of the soil. Nagai
(22), in a cross between two-seeded and three-seeded varieties, found
that about 70 percent of the pods that segregated in the F2 generation
were two-seeded.
Under changeable weather conditions most soybean varieties tend
to shatter their seeds readily. Some varieties, however, such as the
Biloxi and Manchu, have been noted that hold their seeds better than
others. The wild soybean shatters very easily and the Medium Green
begins to shatter with the first mature pods. Piper and Morse (81),
in a, cross between the Medium Green and a glabrous nonshattering
variety (F. P. I. No. 22876) from Japan, found the nonshattering
character to be dominant to the shattering character of the Medium
Green. Nagai (22) found in hybrid progeny of cultivated and wild
soybeans that the shattering character was dominant to nonshattering,
the segregation ratio in the F2 being 3 shattering to 1 nonshattering.
Sterility, Growth Habit
As early as 1908, Piper and Morse (31) found small dwarf like plants,
bearing few or no pods, in the different hybrid selections at the Arling-
ton Experiment Farm. These plants were sterile or nearly so.
Owen (28) describes a sterile strain in which both ovules and pollen
grains were nonfunctional. This strain was found in a progeny of
Manchu soybeans that segregated into 3 normal to 1 sterile, appar-
ently a single-gene mutation being responsible.
All soybeans are strictly determinate as to growth, that is, the plants
reach a definite size according to environment and then mature and
die. The great majority of varieties are erect and branching with a
well-defined main stem. The branches may be all short, or the lower
ones elongated, either spreading or ascending. In other varieties the
stems and branches, especially the elongated terminals, are more or
less twining and usually weak, so that the plants are only suberect
or even procumbent. The latter kind is represented by varieties
from India and certain Siberian varieties of Glycine gracilis. The
stem of the wild soybean (G. ussuriensis) is long and twining with
a procumbent habit. Karasawa (9) in crossing experiments with
the wild and cultivated soybeans found the F, hybrid of a twining
nature. All of the plants of the F2 and F3 generations were more
or less twining.
SOYBEANS 1175
Seed Characters
Color of Seed Coat, Hilum, and Cotyledon
Most varieties of soybeans have unicolored seeds of straw yellow,
olive yellow (greenish yellow), green, brown, or black. In some varie-
ties straw-yellow seeds are very pale, especially when old, and they are
sometimes erroneously called white, but no truly white seeds are
known in soybeans. In straw-yellow varieties, the seeds have a green-
ish tinge if harvested before they are fully mature, which sometimes
makes it difficult to distinguish them from varieties whose fully mature
seeds are greenish yellow. Bicolored seed occurs in several Varieties
such as Black Eyebrow, Meyer, Taha, and Kura. The most common
of the bicolored patterns is green or yellow with a saddle of black or
brown, the latter not being sharply delineated. Some varieties have
their seeds brindled brown and black, the two colors somewhat con-
centrically arranged. One variety has black seeds faintly marked
with minute brown specks. On heterozygous plants the seeds are
often irregularly bicolored and in some cases tricolored. Several
black and a few brown varieties, with the outer layer of the testa
broken by numerous cracks so as to expose the inner white layer,
have been introduced from Chosen. In the case of the black-seeded
and one or two brown-seeded introductions, this splitting has a net-
like appearance that gives the beans a black-and-white or brown-and-
white color.
Individual selections of natural hybrids by Piper and Morse (31)
at the Arlington Experiment Farm gave some rather interesting re-
sults in the breaking up of the various seed colors. The selections
with a single seed color, as straw yellow, black, or brown, broke up in
simple Mendelian proportions, while those with more than one color
presented a different ratio in the progeny.
Nagai (20) makes the following classification of soybeans according
to color of seed coat:
(1) Beans producing no anthocyanin pigment in the seed coat.
(2) Beans produciug anthocyanin pigment in the seed coat.
Owen (27) found the following classification of seed-coat color in
soybeans most useful for the purpose of interpreting Mendelian
characters:
(1) Self-color typo.
(2) Bicolor type.
(3) Eyebrow pattern with green or yellow background.
(4) Green or yellow seed coat with dark hilum.
(5) Green or yellow seed coat with light hilum.
The genetic relationships of seed-coat colors and the effect of other
fenes on the colors have been studied extensively by Woodworth (55),
Tagai (22) , Owen (27), Terao (43), and Stewart (35) . The inheritance
of seed-coat color in soybeans differs somewhat from that of other
members of the legume family. In soybeans, those seed-coat colors
producing no plastid pigments as a rule mask those producing plastid
pigment. The black pigment, according to Owen (29), is a very in-
tense purple belonging to the general class of anthocyanins. The
brown pigment is closely related to quercetin, and the green and
yellow are plastid pigments.
1176 YEARBOOK, 1937
According to Woochvorth {55), the black and brown pigments are
genetically independent of green and yellow in inheritance. Black
is dominant to brown, and in F2 a ratio of 3 black to 1 brown is ob-
tained. Green is dominant over yellow, and in F2 a ratio of 3 green
to 1 yellow is obtained. When black or brown is crossed with green
or yellow, the results are influenced by genes for inhibition of black
and brown pigments over the seed coat. Owen (27) cites a case of
incomplete dominance over brown. A natural hybrid was acciden-
tally found that segregated according to a ratio of 3 black to 1 brown
in the progeny that was grown, but all heterozygous plants bore seed
slightly speckled with brown. It is believed that this brown speck-
ling or flecking on the black seed coat is different from that symbolized
by Woodworth (see table 2, symbol Fl.).
Varieties of soybeans exhibit a wide range of color types in the
hilum, ranging from a pale-yellow or colorless hilum through various
shades of brown to black. Two complementary genes for black pig-
ment formation in the seed coat and hilum have been affirmed by
Nagai (22), Woodworth (55), and Owen (27). The symbols for these
genes were designated C and L by Nagai, B and H by Woodworth,
and B and R2 by Owen, the symbolism given by Owen appearing to be
preferable according to Woodworth (68). In some early experiments
which led to the suggestion of complementary factors for black hilum,
Woodworth (55) obtained, in a cross between a strain with a black
hilum and a strain with colorless hilum, black- and brown-hilum
plants in the ratio of 9 : 7. He pointed out, however, that the ratio
probably was 9 black : 6 brown : 1 colorless, because, on account of
mottling of the seed coat, the plants having seed with brown hilums
could not be easily distinguished from plants having seed with color-
loss hilums, and consequently they were classed together. Nagai
(22) found in a cross between a plant having seed with a light-brown
hilum and a plant having seed with a dark-brown hilum that the Ft
plants have slightly brownish seed and the F2 may be dark brown,
brown, and light brown in a 1 : 2 : 1 ratio. Woodworth (68), in crosses
with parents of dark-brown hilum and light-brown hilum, found that
the difference in the intensity of hilum color is due to the genes T, t, for
tawny v. gray pubescence. Plants with T have dark-brown hilums,
and plants with t have light-brown hilums. The genes for purple and
white flowers (W^Wi) have also been found to influence black and
brown seed coat or hilum colors.
The cotyledons in the soybean are of two colors, yellow and green.
When young the cotyledons are green, but in most varieties they
turn to yellow toward maturity, while some varieties retain the
original green. The behavior of the green and yellow cotyledons in
natural and artificial hybrids has given some very interesting results.
In 1909 Piper and Morse (81) noted in hybrid selection work that,
with many plants having straw-colored to greenish-yellow seeds, seeds
with green cotyledons and seeds with yellow cotyledons occurred on
the same plant and sometimes in the same pod. These plants pro-
duced three kinds of progeny— those bearing only yellow-cotyledon
seeds, those bearing only green-cotyledon seeds, and those bearing
both kinds. The ratio was approximately 1:1:2, respectively, indi-
cating that yellow was a simple Mendelian dominant to green. This
SOYBEANS 1177
segregation in cotyledon color has been confirmed by Woodworth (55),
who found evidence for two (duplicate) genes for yellow cotyledon.
Terao (48) found in crosses that the cotyledon color of the hybrid
progeny was the same as that of the female parent in every case and
that there Was no evidence of segregation in succeeding generations,
indicating that cotyledon color in soybeans is maternal in inheritance.
Maternal inheritance of cotyledon color in the soybean has been
substantiated by Piper and Morse (81) and by Owen (24)-
At least two kinds of transmission of the colors of the cotyledon are
known. One is transmission through the maternal plant — that is, if
the female parent is yellow the cotyledon of Fi becomes yellow, and
if it is green Fi shows green cotyledons. Terao (48) suggests that there
are two factors, 6 and Y, representing chlorophyll in two cotyledon
colors. 6 is the one that always remains green and Y is the one that
changes to yellow. In the other case of the inheritance of the coty-
ledon color, a simple Mendelian ratio has been obtained in F2 in which
yellow- and green-cotyledon seeds occur in a 3:1 or 15:1 ratio according
as the parents differ by one or more genes.
Other Seed Characters
Defective or cracked seed coats have been observed by several
investigators in black-, brown-, and yellow-seeded varieties and rarely
in those having green seed. In some yellow and green seeds mottled
with brown, the defects, or cracking, are found to occur mostly in
brown areas. The character is undesirable, for in the defective or
cracked areas the very thin inner coat cannot furnish the protection
against unfavorable weather and disease organisms that is afforded
normal soybeans in which the seed coat completely covers the seed.
Stewart and Wentz (87), in a cross between the Wisconsin Black and
Mandarin varieties, obtained in the F2 51 normal to 5 defective or
cracked, suggesting a 15:1 ratio. Nagai (22), in a cross between
plants with normal and defective seed coats, found the defective or
cracking character to be partially dominant. In F2 a large number
of individuals were produced showing different degrees of cracking, a
rough estimate giving a ratio of 9 defective or cracked to 7 normal.
Nearly all varieties of soybeans have a comparatively smooth seed
coat but differ more or less in the degree of smoothness. In some
varieties the seed coat is rather dull in appearance, while in others it is
bright and glossy. In the variety Sooty, some black and brown
Siberian varieties of Glycine gracilis, and the wild soybean there is
a distinct bloom covering the entire seed coat. The bloom can easily
be scraped off, exposing the comparatively smooth seed coat under-
neath. In a cross between the Sooty and Manchu varieties, Wood-
worth (63) obtained a 3 : 1 ratio in the F2 generation, while in another
cross a 27 : 37 ratio was found in the F2. In interpreting these ratios,
he assumes that three genes, B1( B2, and B3, are involved and that all
three must be present together to manifest the bloom. If any one of
these genes is not present, the character does not develop.
The range in size of soybean seed varies according to the variety,
each variety having its own typical seed size. Varieties and introduc-
tions tested at the Arlington Experiment Farm ranged in average
weight of 100 seeds from about 4 grams for the smallest to about
138904°— 37— —75 ++
1178 YEARBOOK, 1937
40 grams for the largest. Although seed size is mentioned in numerous
published descriptions of soybean varieties, Nagai (22) and Takagi (89)
are apparently the only investigators who have made studies of the
inheritance of this character, the same results being obtained by both.
In a cross of small seed (100 seeds =10.2 grams) X large seed (100
seeds=25.5 grams) Nagai obtained from the F1 generation seed inter-
mediate in size (100 seeds=14.2 grams). The segregation in the F2
plants gave a wide range of variation between the seed sizes of the
parent. Nagai states that it is very difficult to find plants bearing
seeds of the same size as those of the larger plant and believes that
many factors are involved in the inheritance of size of seed.
A considerable mottling of the seed of many yellow- and green-
seeded varieties occupied the attention of plant breeders more than a
decade ago. This mottling consisted of patches, blotches, or bands
of black or brown pigment, irregular in outline and extent, super-
imposed on a ground color of yellow or green. Seeds with black hilums
were mottled with black, and seeds with brown or colorless hilums
were mottled with brown. In 1924 Wood worth and Cole (66) de-
scribed the character and believed the cause to be physiological
rather than genetical. After further studies, Woodworth states that
the problem of mottling has some genetic aspects and also that a
strain may be developed by selection that lacks the objectionable
feature of mottling exhibited by the original varietjr. This is sub-
stantiated by selection of nonmottling plants from the Dixie variety,
resulting in a pure yellow-seeded strain. Owen (26) concluded after
an extensive investigation of this subject that mottling is due both to
hereditary and environmental factors. In artificial hybrids the pu-
bescence color was found in one instance to influence the extent of
mottling, tawny pubescence increasing it, gray pubescence decreasing
it. Owen, however, could not designate any particular factor as
being the most important in causing mottling. The problem had
certain genetic aspects, but the environmental effects were also quite
evident. In recent years, mottling has not appeared to any great
extent and it has been suggested that perhaps the wider use of varieties
not subject to mottling has been an important factor.
Yield of Seed
In considering the most desirable character in varieties of soybeans,
the most valuable single desideratum, as with other crops, is high
yield of seed. Other characters of course are important, such as habit
of growth, seed quality, color of seed, ease of shattering, etc., but
extensive tests are being conducted at experiment stations in States
where soybeans are an important crop to determine the best yielding
varieties.
From the standpoint of inheritance, seed yield is a very complex
character. The amount of seed produced is determined by heredity
and environment (soil fertility, soil type, method of culture, and
seasonal conditions). Woodworth (68), in studies of the yield charac-
ter, has analyzed yield of seed into its component parts — number of
nodes, number of pods per node, number of seeds per pod, percentage
of abortive seed, and size of seed- — and attempted to evaluate each
variety studied with respect to these components. The general
SOYBEANS 1179
situation was that any particular variety was found to rank well in
one or more components and low or medium in others. No variety
was found to rank highest in all. The conclusion reached was that
the method of cross-breeding that has for its object the production of
types with all yield components expressed to a higher degree than in
the parents appears to be a promising method of breeding for in-
creased seed yield in the soybean.
Disease Resistance
Although the soybean is attacked by a number of bacterial and
fungus diseases, none of which reach serious proportions in oriental
countries, no one disease as yet has caused serious injury to the crop
in the United States. As cultivation continues, however, diseases
undoubtedly will increase and assume more serious proportions.
Breeding for disease resistance, therefore, may become an important
factor in the improvement of the soybean. Studies of the various
diseases of the soybean already found in this country indicate that
varieties differ markedly in relative resistance to certain bacterial and
fungus diseases.
Woodworth and Brown {65), in studies on varietal resistance and
susceptibility to bacterial blight {Bacterium glycineum Coerper),
found that field experiments indicated that soybean varieties vary
greatly in their relative susceptibility to the bacterial blight. Of 48
varieties studied, about half were completely resistant, and the other
half ranged from complete susceptibility to partial resistance.
A bacteria] blight {Bacterium sojae Wolf) of soybeans was found on
a number of varieties in North Carolina by Wolf {52). Studies failed
to disclose any evidence of varietal resistance or susceptibility in any
of the varieties.
Lehman and Woodside {16) made a very extensive study on resist-
ance and susceptibility of soybean varieties to the bacterial pustule
disease {Bacterium phaseoli sqjense Hedges). After field observations
and inoculations in greenhouse plantings, they were able to classify
56 varieties with respect to their resistance and susceptibility to the
disease.
Extensive studies and experiments have been made on the mosaic
disease of soybeans by Kendrick and. Gardner {IS). Results indicated
quite clearly that varieties differ greatly in relative resistance and
susceptibility.
"Brown spot" {Septoria glycines Hemmi), a fungus disease attacking
the foliage of the soybean, has been studied by Wolf and Lehman {53),
who noted differences among soybean varieties in relative resistance
and susceptibility.
Another fungus disease, fusarium blight {Fusarium bulbigenum Oke.
and Mass. var. tracheiphilum (E. F. Sm.) Wr.), was observed in North
Carolina by Cromwell {8). In extensive variety tests, all varieties
were found susceptible with the exception of the Black Eyebrow,
which in two tests showed considerable resistance.
Lehman {15), in a study of another disease, frogeye leaf spot
{Cercospora daizu Miura), attacking the foliage of the soybean, found
that the early-maturing varieties in a certain group escaped serious
injury while the late-maturing sorts suffered most.
1180 YEARBOOK, 1937
Identification of Genes and Chromosomes
Several synonymic difficulties were encountered in establishing the
identity of genes that different investigators have studied and desig-
nated differently. In cooperation with Woodworth and Williams, of
the Illinois Agricultural Experiment Station, literature on the genetics
of the soybean was reviewed thoroughly as to the genes of the soy-
bean, and symbols were designated for each by the various geneticists.
Liberty was taken in some cases to assign symbols to genes that have
been studied but not named and certain symbols have been changed
I
r2
dpi © "2
qei , ,
0 6 13
pi n
_l 1
30
3 G- %
0 13
A de2_P_2
Figure 10. — Chromosome chart showing four groups of linked genes in soybeans.
(Courtesy of C. M. Woodworth and L. F. Williams, Illinois Agricultural Experiment
Station.)
(Woodworth, 63) in order to bring them into line with current usage.
Every effort has been made to make the list given in table 2 of the
appendix as complete as possible, and it is hoped that the list given
here will help to establish greater conformity in the designation of
soybean genes in the future.
According to counts made by Karpetschenko, Kawami, Fukuda
(Karasawa, 9), and Veatch (48), the chromosome number in soybeans
is given as 20 for the haploid and 40 for the diploid condition. The
same number has also been counted in the wild soybean by Tschechow
and Kartaschowa (45), as well as Fukuda (6). In Fx hybrids between
the wild and cultivated species of soybeans, Karasawa (9) found the
same somatic chromosome number as in the parents. No abnormali-
ties were found in the pollen mother cell in the course of sporogenesis,
and the pollen therefrom was normal. Moreover, the fertility of the
Fi and its progeny was quite normal, indicating that the two species
contain on the whole the same kind of genom.
Linkage studies in the soybean have not been very extensive, due
largely, perhaps, to the difficulty of making artificial crosses. Wood-
worth, Nagai and Saito, Owen, and Stewart and Wentz have been the
chief contributors to our meager knowledge of the association of genes
in inheritance in the soybean. In table 3 of the appendix are shown
the linkage groups reported up to the present time.
A provisional chromosome map of soybeans showing linkage rela-
tions of a few factors is given in figure 10. In chromosome 1, the gene
order may not be as represented, since Eand D2 have not been studied
together. In chromosomes 3 and 4, the order may be as represented
or reversed.
SOYBEANS 1181
SELECTED REFERENCES ON GENETICS OF THE SOYREAN
(1) BORDAKOV, P. P.
1933. THE THEORY OF CORRELATION AS APPLIED TO THE BREEDING OP THE
soybean. Trudy Prikl. Bot., Genetike t Selek. (Bull. Appl.
Bot., Genetics, and Plant Breeding) (3), 1: 195-225, illus. [In
Russian. English summary pp. 224-225.]
Cole, L. J., Lindstrom, E. W., and Woodworth, C. M.
1927. selection for quality of oil in soybeans. Jour. Agr. Research
35: 75-95, illus.
Cromwell, R. O.
1919. FUSARItTM blight of the soy bean and the relation of various
factors to infection. Nebr. Agr. Expt. Sta. Research Bull.
14, 43 pp., illus.
Cutler, G. H.
1934. a simple method for making soybean hybrids. Jour. Amer.
Soc. Agron. 26: 252-254.
Etheridge, W. C, Helm, C. A., and King, B. M.
1929. a classification of soybeans. Mo. Agr. Expt. Sta. Research
Bull. 131, 54 pp., illus.
Fukuda, Y.
1933. cyto-genetical studies on the wild and cultivated man-
churian soy beans (glycine l.). Japan. Jour. Bot. 6: 489-506,
illus.
Garber, R. J., and Odland, T. E.
1926. natural crossing in soybeans. Jour. Amer. Soc. Agron. 18:
967-970.
Johnson, H. W., and Hollowell, E. A.
1935. pubescent and glabrous characters of soybeans as related
to resistance to injury by the potato leaf hopper. Jour.
Agr. Research 51: 371-381, illus.
Karasawa, K.
1936. CROSSING experiments with glycine soja and g. ussuriensis.
Japan. Jour. Bot. 8: 113-118, illus.
Kawakami, J.
1930. chromosome numbers in leguminosae. Bot. Mag. Tokyo 44:
319-328, illus. [Japanese and English.]
Keilholz, F. J., Comp. and ed.
1925. soybeans being bred for higher oil content. 111. Agr. Expt.
Sta., Ann. Rept. (1923-24) 37: 31-32, illus.
Kendrick, J. B., and Gardner, M. W.
1921. seed transmission of soybean bacterial blight. Phytopa-
thology 11: [340]-342, illus.
and Gardner, M. W.
1924. soybean mosaic; seed transmission and effect on yield.
Jour. Agr. Research 27: 91-98.
Kihara, H., Yamamoto, K., and Hosono, S.
1931. studies on chromosome numbers of plant. 352 pp., illus.
Tokyo. [In Japanese.]
Lehman, S. G.
1928. FROG-EYE LEAF SPOT OF SOY BEAN CAUSED BY CERCOSPOHA DIAZU
miura. Jour. Agr. Research 36: 811-833, illus.
— and Woodside, J. W.
1929. VARIETAL RESISTANCE OF SOYBEAN TO THE BACTERIAL PUSTULE
disease. Jour. Agr. Research 39: 795-805.
Lbith, B. D.
1924. FLUCTUATING VARIATIONS IN THE SOY BEAN. Jour. Amer. SoC.
Agron. 16: 104-108.
Maceda, F. N.
1919. EXPERIMENTS ON SEED SELECTION FOR PHILIPPINE CULTIVATION.
Philippine Agr. and Forester 8: 92-98.
Matsuura, H.
1929. A BIBLIOGRAPHICAL MONOGRAPH OF PLANT GENETICS (GEN1C
analysis) 1900-1025. 499 pp. Tokyo. (Tokyo Imp. Univ.,
Faculty Sci. Bot. Inst. Contrib. Cytol. and Genetics 82.)
1182 YEARBOOK, 1937
(20) Naqai, I.
1921. A GENETICO-FIIYSIOLOGICAL STUDY ON THE FORMATION OP ANTIIO-
CYANIN AND BROWN PIGMENTS IN PLANTS. Joiir. Col. Agr.,
Imp. Univ. Tokyo 8: 1-92, illus.
(21)
(22)
1924. OBSERVATIONS ON THE SOMATIC BEGKEGATION IN SOY BEANS.
Japan. Jour. Bot. 2: 63-70.
1926. ON the heeedity op the soybean. Separate Mag. Noggo and
Engei v. 1, nos. 1-2. [In Japanese.]
(23) and Saito, S.
1923. linked factousin soybean. Japan. Jour. Bot. 1: [121]-136.
(24) Owen, F. V.
1927. inheritance studies in soybeans, i. cotyledon color. Gene-
tics 12: 441-448.
(25)
1927. inheritance studies in soybeans, ii. glabrousness, color op
pubescence, time op maturity, and linkage relations.
Genetics 12: [519]-529.
1927. hereditary and environmental factors that produce mot-
tling in soy beans. Jour. Agr. Research 34: 559-587, illus.
1928. inheritance studies in soybeans, rn. seed-coat color and
SUMMARY OP ALL OTHER MENDELIAN CHARACTERS THUS FAR
reported. Genetics 13: 50-79, illus.
1928. A sterile character in soybeans. Plant Physiol. 3: 223-226,
illus.
(26)
(27)
(28)
(29)
1928. soybean seeds with two embryos. Jour. Heredity 19: 373-374
illus.
(30) Piper, C. V., and Morse, W. J.
1910. THE soy bean; history, varieties, and field studies. U. S.
Dept. Agr., Bur. Plant Indus. Bull. 197, 84 pp., illus.
(31) and Morse, W. J.
1923. the soybean. 329 pp., illus. New York.
(32) Russell, H. L., and Morrison, F. B.
1922. breeding for oil in soybeans. Wis. Agr. Expt. Sta. Ann. Rept.
(1920-21) Bull. 339: 113-114.
(33) Skvortzov, B. V.
1927. THE SOYBEAN, WILD AND CULTIVATED IN EASTERN ASIA. Man-
churian Research Soc. Pub. ser. A, Nat. Hist. Sec, no. 22, 18 pp.,
illus. [In Russian. Summary in English.]
(34) Stewart, R. T.
1927. dwarfs in soybeans. Jour. Hereditv 18: 281-284, illus.
(35) •
1930. INHERITANCE OP CERTAIN SEED-COAT COLORS IN SOYBEANS. Jour.
Agr. Research 40: 829-854.
(36) and Wentz, J. B.
1926. A RECESSIVE GLABROUS CHARACTER IN SOYBEANS. JoUT. Amer.
Soc. Agron. 18: 997-1009, illus.
(37) and Wentz.
1930. a defective seed-coat character in soy-beans. Jour. Amer.
Soc. Agron. 22: 657-662, illus.
(38) Swen, M. S. D.
1935. new findings of sterility in soybeans. Hopei Agr. and For-
estrv, v. 1, no. 1.
(39) Takagi, F.
1929. ON THE inheritance of some characters in glycine soja,
bentham (soy-bean). T6hoku Imp. Univ. Sci. Rept., 4th scr.,
Biol. 4: 577-589, illus.
(40) Takagi, M.
1926. ON THE FREQUENCY' OF THE SPONTANEOUS HYBRIDIZATION IN SOY-
BEAN. Korea Agr. Expt. Sta. Notes 4: 323-324. [Abstract in
Japan. Jour. Bot. 3: (68) . 1927.]
SOYBEANS 1183
(41) Takahashi, N.
1934. LINKAGE RELATION BETWEEN THE GENES FOE THE FORMS OF LEAVES
AND THE NUMBER OF SEEDS PER POD OF SOYBEANS. Japan. JoUr.
Genetics 9: 208-225. [In Japanese. English summary, p. 225.]
(42) Takahashi, Y., and Fukuyama, J.
1919. MORPHOLOGICAL AND GENETICAL STUDIES OF THE SOYBEAN. Hok-
kaido Imp. Agr. Expt. Sta. Kept. 10, 100 pp., illus. [In Japa-
nese.]
(43) Terao, H.
1918. maternal inheritance in the soy bean. Amer. Nat. 52: 51-56.
(44) and Nakatomj, S.
1929. on the inheritance of chlorophyll colorations of COTYLEDONS
and seed-coats in the soybean. Japan. Jour. Genetics 4:
[64]-80. [In Japanese. Resume in English, pp. 79-80.]
(45) Tschechow, W., and Kartaschowa, N.
1932. karyolisch-systematische untersuchungen der tribus loteae
UND PHASEOLEAE UNTERFAMILIE PAI'ILIONATAE. Cvtologia 3:
221-249, illus.
(46) Veatch, C.
1930. VIGOR IN SOYBEANS AS AFFECTED BY HYBRIDITY. Jotir. Amer. SoC.
Agron. 22: 289-310, illus.
1930. VIGOR IN SOYBEANS IN RELATION TO INHIBITION OF PUBESCENCE.
Jour. Amer. Soc. Agron. 22: 446-452.
(47)
(48)
1 934. chromosomes o,f the soy bean. Bot. Gaz. 96: 189, illus.
(49) and Woodworth, C. M.
1930. GENETIC RELATIONS OF COTYLEDON COLOR TYPES OF SOYBEANS.
Jour. Amer. Soc. Agron. 22: 700-702.
(50) Wentz, J. B., and Stewart, R. T.
1924. hybrid vigor in soybeans. Jour. Amer. Soc. Agron. 16: 534-540,
illus.
(51) — and Stewart, R. T.
1927. EFFECT OF A SEMI-LETHAL FACTOR UPON YIELD IN SOYBEANS WHEN
present in the heterozygous condition. Jour. Amer. Soc.
Agron. 19: 850-853.
(52) Wolf, F. A.
1920. bacterial blight of soybean. Phytopathology 10: [119]-132,
illus.
(53) and Lehman, S. G.
1926. brown-spot disease of soy bean. Jour. Agr. Research 33: 365-
374, illus.
(54) Woodhouse, E. J., and Taylor, C. S.
1913. THE VARIETIES OF SOYBEANS FOUND IN BENGAL, BIHAR, AND ORISSA,
and their commercial possibilities. India Dept. Agr. Mem.,
Bot. Ser. 5: [103]-175, illus.
(55) Woodworth, C. M.
1921. inheritance of cotyledon, seed-coat, hilum and PUBESCENCE
colors in soy-beans. Genetics 6: [487]-553, illus.
(56)
(57)
(58)
1922. THE EXTENT OF NATURAL CROSS-POLLINATION IN SOYBEANS. JoUT.
Amer. Soc. Agron. 14: 278-283.
1923. CALCULATION OF LINKAGE INTENSITIES WHERE DUPLICATE FACTORS
are concerned. Genetics 8: [106]-115.
(59)
(60)
(61)
1923. INHERITANCE OF GROWTH HABIT, POD COLOR, AND FLOWER COLOR
in soybeans. Jour. Amer. Soc. Agron. 15: 481-495, illus.
1925. fortuitous variation. Amer. Nat. 59: 375-379.
1928. relative infrequency of soybean varieties having only one
factor for yellow cotyledon. Genetics 13: 453-455.
1930. abortive seeds in soybeans. Jour. Amer. Soc. Agron. 22: 37-50,
illus.
1184 YEARBOOK, 1937
(62) Woonwoitra, C. M.
1931. soybean" breeding. Amer. Sovhean Assoc, Proc. (1930) 3: 80-82.
(63)
1932. GENETICS AND BREEDING IN THE IMPROVEMENT OF THE SOYBEAN.
III. Agr. Expt. Sta. Bull. 384, pp. 297-404, illus.
(64)
1933. genetics of THE soyhean. Jour. Anicr. 1S00. Agron. 25: 36-51,
illus.
(65) and Brown, F. C.
1920. STUDIES ON VARIETAL RESISTANCE AND SUSCEPTIBILITY TO BACTERIAL
blight op the soybean. (Abstract) Phytopathology 10: 68.
(66) and Cole, L. J.
1924. mottling of soybeans. Jour. Heredity 15: 349-354, illus.
(67) — ■ and Veatch, C.
1929. inheritance of pubescence in soybeans AND ITS HALATION' TO
pod color. Genetics 14: [512]-518.
APPENDIX
Workers Identified With Soybean Improvement
United States
United States Department of Agriculture, Bureau of Plant Industry, Division of
Forage Crops and Diseases:
W. J. Morse, Washington, D. C.
W. M. Stuart, Jr., and C. H. Binkley, Arlington Experiment Farm, Arling-
ton, Va.
J. L. Cartter, Urbana, 111.
M. G. Weiss, Ames, Iowa.
J. L. Stephens, Tifton, Ga.
T. F. Akers, West Point, Miss.
R. E. Stitt, Statesville, N. C.
H. A. Schoth, Corvallis, Oreg.
State agricultural experiment stations:
Alabama, Auburn: H. B. Tisdale.
Arkansas, Fayettevillo: C. K. McClelland. Stuttgart: G. H. Banks.
California, Berkeley: W. W. Mackie.
Colorado, Fort Collins: D. W. Robertson, A. Kczer.
Delaware, Newark: G. L. Schuster.
Florida, Gainesville: G. E. Ritchey. Belle Glade: A. Daane. Quincy:
J. D. Warner.
Georgia, Athens: J. R. Fain. Experiment: R. P. Bledsoe.
Illinois, Urbana: C. M. Woodworth, W. L. Burlison, J. C. Hackleman, L. F.
Williams.
Indiana, La Favette: G. H. Cutler, R. R. Mulvey, K. E. Beoson, A. H.
Probst,
Iowa, Ames: H. D. Hughes, J. B. Wentz.
Kansas, Manhattan: J. W. Zahnley.
Kentucky, Lexington: E. J. Kinney.
Louisiana, Baton Rouge: J. P. Gray.
Maryland, College Park: J. E. Metzger, R. G. Rothgeb.
Michigan, East Lansing: C. R. Megee.
Minnesota, St. Paul: A. C. Amy, W. M. Mvers.
Mississippi, State College: W. R. Perkins, L F. O'Kellv. Stoneville: H. A.
York. Poplarville: J. C. Robert.
Missouri, Columbia: W. C. Etheridge, C. A. Helm, B. M. King.
New Hampshire, Durham: F. S. Prince.
New Jersey, New Brunswick: H. B. Spraguc.
New York, Ithaca: R. G. Wiggans.
North Carolina, Raleigh: C. B. Williams, R. L. Lovvorn.
North Dakota, Fargo: A. F. Yeagcr.
Ohio, Columbus: J. B. Park, P. Preston. Wooster: L. E. Thatcher.
Oklahoma, Stillwater: B. F. Kiltz.
Pennsylvania, State College: C. F. Noll, C. E. Myers.
SOYBEANS
]I85
South Carolina, Florence: E. E. Hall.
Tennessee, Knoxville: H. P. Ogden.
Texas, College Station: E. B. Reynolds.
Virginia, Blacksburg: M. S. Kipps. Williamsburg: R. P. Cocke.
West Virginia, Morgantown: J. A. Rigney.
Wisconsin, Green Bay: E. J. Delwiche. Madison: G. M. Briggs, B. D.
Leith.
Foreign Countries
Australia:
Department of Agriculture, New South Wales:
Glenn Innes: S. L. Macindoe.
Traftor: W. H. Darragh.
Richmond: N. S. Shirlow.
Sydney: H. Wenholz.
Canada:
Central Experimental Farm, Ottawa: F. Dimmock.
Dominion Experiment Station, Harrow: C. W. Owen.
Agricultural College, Guelph: O. McConkey.
England:
Royal Botanic Gardens, London: J. L. North.
Germany:
Kaiser Wilhelm Institute, Manchberg: W. Rudorf.
Sudd. Soya-Institut, Mtinchen: K. Baumeister.
Soya-Institut, Mannheim: L. Mtiller.
Japan:
Imperial Agricultural Experiment Station, Tokyo: H. Terao.
Hokkaido Imperial Agricultural Experiment Station, Kotoni: V. Fujine,
T. Hoshino.
Saitama Agricultural Experiment Station, Ageo: T. Hasegawa.
Central Agricultural Experiment Station, Suigen (Chosen): I. Nagai.
Central Agricultural Experiment Branch Station, Shariin (Chosen): Y.
Takahashi.
Akita Agricultural Exporhnent Station, Akita: K. Adachi.
Manchuria:
South Manchuria Railway Agricultural Experiment Stations:
Kungchuling: Y. Nakamoto, S. Tsuda, M. Ishikawa, K. Adachi.
Hsiungyocheng: K. Hisatake.
Kaiyuan: S. Kofuku.
Table 2. — List of genes in soybeans
Symbol
Dominant-recessivo characters
Authority
Date
pub-
lished,
observed,
or
reported
A
1936
Bi. Bi, B%
1932
Ci, C2
Complementary genes for cracking on seed-coat surface. ._
Duplicate genes for yellow cotyledons; didi, green cotyle-
dons.
1926
Di, B2
1921
Dei
Stewart and Wentz.
1930
1935
Df
Dt
1927
1923
E
Early maturity; e, late maturity., ..
Normal stem development;/, fasciated or flattened stein...
Black seed coat flecked or speckled with brown; ft, self or
solid black.
1927
F
1929
M
1930
a
1931
Multiple allelomorphic series responsible for inhibition of
black or brown pigment in seed coat:
7, Total inhibition; seeds show no black or brown
pigment even in hilum.
j', Partial inhibition; permits pigment only in hilum.
tl, Partial inhibition; responsible for Black Eyebrow
pattern.
i, No inhibition; seeds entirely black or brown.
1928
1186
Symbol
L
M
N
No.
Pi
Pi
Ri, ti, n°
R>
S
Sh
Shi
Sp
St
T
TI
w,
X
Vi
Ys, Fs
Yt
Yt
Y,
Y7
Y,
YEARBOOK, 1937
Table 2. — List of genes in soybeans — Continued
Dominant-recessive characters
Dark-colored or black pods; 1, light-colored pods
Responsible for black mottling on a self-brown seed coat;
m, no mottling.
Normal hilum such as is found in most soybean varieties;
n, abnormal hilum such as is found in Soysota variety.
Broad leaflet of most varieties; na, narrow leaflet
Inhibition of pubescence, causing glabrousness; j>i, no
inhibition.
Pubescence; Vh no pubescence
Multiple allelomorphic series for seed-coat color
R, complementary with Ri for black seed coat or hilum.
t\. Complementary with R% for brown seed coat or
hilum; recessive to Ri.
n°, reddish-brown seed coat; recessive to Rt and r.
Complementary with R\ for black seed coat or hilum;
ri, complementary with R\ and «'i for buff coat or hilum;
ri. R\, and Wi, imperfect black.
Tall, late-maturing type; s, stocky, early-maturing type_-
Nonshattering of F. P. I. 22876, dominant to shattering of
Medium Green; sh, shattering of Medium Green.
Shattering of wild soybean, dominant to nonshattering of
Kuradaizu; shi, nonshattering of Kuradaizu.
Spreading or fan-shape habit of growth; sp, erect compact
habit of growth.
Normal production of seed; s, sterility.-
Tawny or brown pubescence color; t, gray pubescence
color.
Normal chlorophyll development; fi, variegation
Colored flowers; wi, white flowers...
Complementary with Wt for purple flower color; wi with
W\ gives purplish-blue flowers; wi with Wi or wi, white
flowers.
Extra leaflets in compound leaf; x, normal number, three..
Normal green plant; Vi, greenish-yellow leaves; weak
plant.
Complementary for green plant; vs yi, leaves turn yellow
as plant grows; vigor fair.
Normal green plant; m, yellowish leaves; mutant found
in Wilson-V.
Normal green plant; ys, yellow-green leaves; mutant found
in F. P. I. 65388; plant low in vigor.
Normal green plant; yt, pale-green leaves; mutant found
in ltokusun variety.
Normal green plant; !/;, leaves, stem, and pods become
yellow as plant develops. Mutant found in Fuji.
Normal green plant; Vs. yellow-green leaves in young
plant, becoming green as plant develops.
Authority
Wood worth
Nagai and Saito.
Oweu.
Takahashi and Fu-
kuyama.
Nagai and Saito
Stewart and Wentz.
Nagai
Owen
1923
Piper and Morse
1911
Nagai... .
1926
do
1926
Owen .. .-
Piper and Morse
1928
1910
Woodworth
Piper and Morse
Takahashi and Fu-
kuyama.
1932
1910
1919
Nagai
do. ..
1926
1926
do-
1926
1931
do__
1932
1936
do
1936
Woodworlh
1935
Date
pub-
lished,
observed,
or
reported
1923
1923
192S
1919
1923
192S
1921
Table 3. — Linkage of soybean characters
Characters associated
Symbols
Percent-
age
crossing
over
Authority
Dato
pub-
lished,
observed,
or
reported
G, di
T,R2
E, T
dei, t
Pi, n
P., M
T,di
det, pt
13
0
6
0
12
18
13
2
1921
1927
Tawny pubescence and black seed coat or hilum
color.
1932
1927
Stewart and Wentz .
1930
Inhibition of pubescence and brown seed coat or
hilum.
Inhibition of pubescence and black mottling on a
self-brown seed coat.
Pubescence color and cotyledon color
Defective seed coat and pubescence- - ..
1927
Nagai and Saito. .
1923
1935
do _
1935
Table 4. — Soybean varieties: Origin and varietal characteristics '
Variety
Agate
A. K.
Aksarben
Arlington
Arksoy
Avoyelles _
Bansei
Barcnet
Biloxi
Black Eyebrow
Cayuga
Chame.-
Ohernie _.
Chestnut
Chiquita
Chusei
Columbia
Creole
Delnoshat
Delsta
Dixie
Dunfleld
Easycook..
Ebony
Elton.. _
Fuji
George Washington-
Georgian
Goku
Habaro
Haberlandt
Hahto...
Hakote
Harbinsoy
Hayseed
Herman
Higan
Hiro
Origin
Introduction, Japan ,
Introduction, Manchuria
do
Introduction, China
Introduction, Chosen
Selection, Gray, Louisiana
Introduction, Japan
Introduction, China _. ...
do
Introduction, Manchuria
do
Introduction, Japan
Introduction, Siberia... .
Selection, Arlington Experiment Farm-
Introduction, China „ _.
Introduction, Japan... _
Introduction, China
do
Selection, York,' Mississippi
do
Selection, Arlington Experiment Farm.
Introduction, Manchuria
Introduction, China
Introduction, Chosen. ...
Introduction, Siberia
Introduction, Japan
Selection, Clapp,3 Virginia
Introduction, China
Introduction, Japan
Introduction, Siberia
Introduction, Chosen
Introduction, Japan
do
Selection, Arlington Experiment Farm..
Introduction, China
Selection, Herman,2 North Carolina
Introduction, Japan..
do _.
Year
1929
1912
1913
1908
1914
1932
1929
1908
1908
1911
19U5
1929
1906
1907
1910
1929
1908
1927
1925
1925
1914
1913
1894
1901
1906
1929
1921
1927
1929
1906
1901
1915
1929
1922
1927
1915
1929
1930
Days
to
mature
90
110
105
125
140
170
110
150
165
105
100
125
100
105
135
110
125
165
165.
150
135
110
135
125
105
115
135
165
110
105
130
130
115
120
160
135
135
115
Flower
color
p, w
p, w
p, w
P> w
p
p
p
p
p
p, w
w
p
p
P- w
w, p
w
P
p, w
p
P, w
p
p, w
p
p
w
p, w
p, w
p
Pubes-
cence
color
t
E,t
E
E, t
g
t
E
t
t
t
t
t
t
t
E
E
E
t
g
t
E
t
t
t
E
E. t
t
t
t
t
t
t
E
t
Seed characters
Coat
color
sy+br
sy
sy
bl
sy
bl
sy
br
br
bl+br
bl
br
bl
br
sy
sy
gr
sy
sy
sy
sy
sy
sy
bl
sy
oy
br
sy
sy
sy
sy
oy
oy
sy
sy
sy
sy
bl
Germ
color
y
y
y
y
y
y
y
y
y
y
y
y
y
y
y
y
gr
y
y
y
y
y
y
y
y
y
y
y
y
y
y
y
y
y
y
y
y
y
Hilum
color
br
pa to bl
y
bl
br
bl
y
br
br
bl
bl
br
bl
br
br
y
br
bl
br
br
y
br
br
bl
y
bl
br
pa to br
br
br
br
bl
bl
br
br
br
br
bl
Seeds per
pod
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3-4
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
Seeds per
pound
2,816
2,650
2, 675
4,750
3,136
3,248
1,936
9, 950
1,875
2,475
3,632
1,904
4,675
3,275
4, 050
2, 096
3, 350
3,120
2, 340
1,860
1, 825
3,175
2,700
5,750
2, 625
1,456
3,200
3,968
3,216
3,100
2,400
1,250
1,440
2,950
4,176
2, 450
1,984
1,312
gv
gra, f
gra
f
f, gra
f
de, gv
f
f
f
t, gra
gv
f
f
f, gra
de, gv
f
f, gra
gra
gra
gra
gra
de, gra
f
gra
de, gra
f, ns
gra, f
gv
gra
gra, de
gv, de
gv.de
f, gra
f, gra
gra
gv, de
gv, de
1 bl=black; br=brown; de=dry edible beans; f=forage; g=gray; gr=
yellow; t=tawny; w=white.
'Name of breeder.
green; gra=grain; gv=green-vegetable beans; oy=olive or greenish yellow; p=purple; pa=pale; sy=straw
03
-a
Table 4. — Soybean varieties: Origin and varietal characteristics — Continued
Variety
Hokkaido
Hollybrook __.
Hongkong
Hoosier
Hurrelbrink
Illini
Ilsoy
ItoSan.
Jogun
Kanro
Kingwa.. __
Kura
Laredo
Lexington.- _..
Mammoth Brown. __
Mammoth Yellow.-.
Mamredo
Manchu...
Mandarin
Mandell
Mansoy
Medium Green
Merko
Midwest.
Mikado
Minsoy
Monetta
Morse
Mukden
Nanda
Nanking
Norredo
Ogemaw
Old Dominion
Oloxi.
Osaya..
Otootan
Ozark
Palmetto
Pee Dee
Peking
Pine Dell Perfection.
Origin
Introduction, Japan
Selection, Wood,2 Virginia
Introduction, China
Introduction, Manchuria _.
Selection, Hurrelbrink,2 Illinois
Selection, Woodworth,3 Illinois
Selection, Smith,3 Illinois
Introduction, Japan
do
Introduction, Chosen
Selection, Garber,2 West Virginia
Introduction, Japan
Introduction, China
Selection, Arlington Experiment Farm.
Selection, North Carolina
Introduction, origin unknown
Selection, York,2 Mississippi..
Introduction, Manchuria
do..
Selection, Cutler,3 Indiana^.
Selection, Arlington Experiment Farm.
Introduction, Japan
Introduction, Siberia
Introduction, China __
Selection, Parsons,2 Indiana
Introduction, France
Introduction, China
Introduction, Manchuria
Selection, Arlington Farm..
Introduction, Chosen
Introduction, China
Selection, unknown
Selection, Evans,2 Michigan
Introduction, China
Cross, Wilds,2 South Carolina
Introduction, Japan __
Introduction, Taiwan
Introduction, Chosen
Introduction, China
Cross, Wilds,3 South Carolina
Selection, Arlington Experiment Farm-
Selection, Griesenauer,2 Virginia
Year
1930
1902
1908
1911
1902
1921
1913
1890
1930
1929
1921
1929
1914
1907
«
(!)
1925
1911
1911
1926
1915
1889
1906
1901
1905
1910
1927
1906
1920
1932
1927
(:)
1902
1917
(3)
1929
1911
1914
1927
(')
1907
(3)
Days'
to
mature
no
135
120
110
125
105
120
105
1)8
110
125
118
140
130
140
145
150
110
100
115
120
120
115
115
120
100
165
130
105
145
Ifi."
125
90
140
(■")
115
175
130
165
145
125
130
Flower
color
p, w
P. w
P
w
P
P
w
p
p
w
p, w
P. w
p
w
w
p, w
p
p
p
p
P, w
p
p
p
p
I>, w
w
1>
p
p, w
w
p
p
w
p
p
p
p
p, w
p
Pubes-
cence
color
g
B
g,t
e
t
K
t
t
B
S
g
t
t
g
t
g
s
t
g
t
t
t
t, g
t
t
t
t
g
g
g
t
g, t
t
g
t
g
t
t
t
t
t
t
Seed characters
Coat
color
sy
sy
sy
sy
sy
sy
br
sy
sy
sy
bl
bl+oy
bl
oy
br
sy
sy
sy
sy
sy
sy
gr
br
sy
sy
sy
sy
oy
sy
sy
sy
bl
br
br
bl
sy
bl
br
sy
bl
1)1
bl+br
Germ
color
y
y
gr
y
y
y
y
y
y
y
y
y
y
y
y
y
y
y
y
y
y
y
y
Hilum
color
y
br
br
br
br
br
br
y
y
pa to br
bl
bl
bl
br
br
br
br to bl
bl
y
bl
bl
br
br
y to br
br
br
bl
br
br
pa
br
bl
br
br
bl
y
bl
br
bl
bl
bl
bl
Seeds per
pod
2-3
2-3
2-3
2-3
2-3
2-3
2-3
23
2-3
2-3
3
2
2-3
2-3
2-3
2-3
2-3
2-3-4
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-3
Seeds per
pound
1,232
2, 550
3,125
2, 510
2,800
2, 750
3, 250
3,325
1,360
1,488
3, 808
1,456
7,775
3,585
1, 855
2,150
3, 220
2, 350
2. 910
2,448
2,450
2,485
4,900
3,675
3,086
3,700
2,976
2,500
2,750
1,952
5, 600
5, 856
3,125
6, 525
4,100
1,792
6, 150
2,800
3,408
5,100
6,388
3,696
Lse
gv, de
gra
gra
gra
gra
gra
f
gra
gv, de
gv, de
gv
t
f
f, gra
gra
gra
gra
gra
gra
gra
f
f
gra
gra
gra
f, gra
f, gra
gra
de, gv
gra
f
t
f
f
gv, de
i
gra, f
gra, f
I
i
f
Pinpu.. __.
Rokusun
Sato...
Scioto
Shiro
Sooty
Sousei
Southern Prolific.
Soysota— _ .
Sura
Tarheel Black
Toku..
Tokyo
Virginia _..
Waseda _
White Biloxi
Wilson
Wilson-Five_
Wisconsin Black..
Yelredo
Yokoten
Introduction, Manchuria.. _
Introduction, Japan
do.
Selection, Park,2 Ohio—
Introduction, Japan.. _
Selection, Arlington Experiment Farm.
Introduction, Japan _
Introduction, Chosen
Introduction, Italy
Introduction, Japan
Introduction, China
Introduction, Japan...
...do
Selection, Arlington Experiment Farm.
.do.
Selection, York,2 Mississippi..
Introduction, Manchuria
Selection, Arlington Experiment Farm
Selection, Wisconsin Agricultural Experiment Station.
Cross, Wilds,2 South Carolina
Introduction, Japan _
1910
1929
1929
1925
1929
1907
1929
1914
1910
1930
1905
1930
1901
1907
1929
1925
1900
1912
1898
P)
1907
105
140
115
120
115
125
115
135
100
115
140
115
140
125
110
165
125
125
100
165
130
W
p, w
p
p
p
p, w
p, w
w
p
p
P, w
p
p, w
p
p
p
P, T
6
t
t
t
t
t,g
t
g
t
g
t
E
g
t
t
t
t,g
B
t
t
g
sy
sy
bl
sy
oy
bl (dull)
oy
br
sy
bl
sy
?.y
br
sy
sy
bl
bl
bl
sy
sy
br
2-3
2,675
br
2-3
1,584
bl
2-3
1,488
bl
2-3
2,960
br, bl
2-3
1,632
bl
2-3-4
IS, 825
br
2-3
1,840
br
2-3
2,350
br
2-3
4,900
y
2-3
1,320
bl
2-3
2,710
br
2-3
1,952
pa
2-3
2,260
br
2-3
3, 455
pa to br
2-3
2,016
br
2-3
2,230
bl
2-3
2,400
bl
2-3
5,025
bl
2-3
3,085
br
2-3
5,120
br
2-3
2,175
2 Name of breeder.
» Unknown.
gra
gv, de
gv
gra
gv
gv
gra
I
de
I
de, gra
gra, de
f
gv
gra
i
I
I
gra, f
gra
C/2
©
to
CLOVER IMPROVEMENT
A. J. PIETERS, Principal Agronomist,
E. A. HOLLOWELL, Senior Agrono-
mist, Division of Forage Crops and
Diseases, Bureau of Plant Industry
J. HROUGHOUT the world clover has been repeatedly referred to as
the keystone of a permanent agriculture. Its introduction into agri-
cultural use in the sixteenth century profoundly affected the entire
system on which the old agriculture was based. As early as 1663,
Yarranton wrote, in The Great Improvement of Lands by Clover, "for
I perceive the land doth receive wonderful advantage by these leaves
and branches; and as the leaves and branches, so the root doth very-
much contribute towards the enriching of the land." The improve-
ment noted by Yarranton has been observed in every generation since
that time, and to this has been added an increasing appreciation of
clover as forage. Ked clover, especially, is today the most widely
adapted dual-purpose crop available to the farmer of the humid parts
of the United States. Even older is the belief in clover as a lucky plant.
Systematic attempts at improvement, however, are of recent origin.
Many plants have been called clovers, probably because of a simi-
larity in usefulness and appearance to the true clover; but the true
clovers and the sweetclovers only will be considered herein.
The true clovers belong to the genus Trijolium, of which there are
some 250 described species of annual, biennial, and perennial forms
that are widely distributed. In nearly every continent there are
found indigenous species that occur only in that continent. In general
they inhabit cool, moist regions or their growth is confined to the
season of the year when cool climatic conditions prevail. Only four
species — red {Trijolium pratense L.), alsike (T. hybridum L.), white
{T. repens L.), and crimson (T. incarnatum L.) — are of primary im-
portance and widely used, although several others are minor agricul-
tural plants, in some cases of great importance locally.
Though recently considered a weed, sweetclover has had a phe-
nomenal rise to the position of a forage crop of major importance in
the United States. As an immigrant, it established itself along road-
sides and railroad beds before its value was recognized. Sweetclover
is now widely distributed over the world, but its native habitat ap-
pears to be in Asia Minor. Twenty species of sweetclover are recog-
nized by Engler and Prantl. Three species — Melilotus alba Desr., M.
officinalis Lam., and M. indica All. — are of importance in agriculture.
RED CLOVER
Of the true clovers, red clover {Trifolium pratense) is by far the most
important. In the wild state it ranges over most of Europe and far
into Siberia. The plant was known to be generally cultivated in the
1190
CLOVER 1191
Netherlands 370 years ago, and it is possible that there may have been
a much older clover culture among the ancient Letts.
Natural Development
In the wild, red clover is an extremely variable plant. There are
known to be early, late, smooth, hairy, prostrate, erect, and semierect
forms. These forms can be found today, and it seems probable that
one of them was the ancestor of the clover first used in agriculture,
which was substantially like the double-cut clover of Europe today.
The many varieties that have developed since the introduction of red
clover into England in 1645 have resulted from the action of local
conditions rather than conscious selection by man. Many such more
or less local forms still exist, but they differ physiologically rather
than morphologically; that is, they differ in resistance to cold and
disease or in yielding ability rather than in characters that can readily
be distinguished by the eye. In the Netherlands, however, a variety
occurs, known as Maas, that is characterized by the almost total ■
absence of the crescent-shaped white spot on the leaflets; and the
character of rough hairiness readily distinguishes the American clover
from its European progenitor.
Nothing is definitely known regarding the origin of red clover now
common in North America. It is known that red clover was grown
in Rhode Island in 1663 and that in later years th.ere was a constant
importation of seed from England. The American red clover is there-
fore certainly descended from the cultivated red clover of England,
which in turn was introduced from Flanders. Just how the American
form developed its characteristic hairiness is not known, but it has
been surmised that it may have been because of the continued attacks
IN 1928 the United States Department of Agriculture, through the .
cooperation of the State agricultural experiment stations, began a
thorough search for red-clover stocks that had been grown continu-
ously on the same farms or in the same communities for periods of
10 years or more without the introduction of seed from outside
sources. These were planted in small observation plots and used
as a basis for determining regional needs in red-clover-breeding
programs for the humid Eastern States. It turned out that in the
southern region red clover must be especially resistant to anthrac-
nose; in the central region it must be both winter-hardy and disease-
resistant; in the northern region it must be able to withstand a long
period of winter dormancy; and in all regions resistance to powdery
mildew is of varying importance. Breeding work based on these
needs is now in progress, and some superior strains have already
been introduced or are well advanced.
1192 YEARBOOK, 1937
of leafhoppers, which are common on clover and which prevent seed
production in the smooth more than in the hairy plants. The English
clover contains a certain percentage of hairy plants that, on this
theory, would persist and hence gradually develop a hairy form (fig. 1).
Figure 1. — Stems of Italian red clover (A), American (B), and English broad red (C),
showing the hairiness of American, believed to have been derived from the English
by natural selection.
Classes of Cultivated Red Clover
In both Europe and North America the cultivated red clovers fall
into two classes — (1) early, or double-cut, these giving two hay crops
in a season; and (2) late, or single-cut, these giving but one hay crop
in a season; and in most cases two or more forms are known in each
class. Such forms are more numerous in the double-cuts than in the
single-cuts and with a few exceptions are local or regional, rather
than true varieties. Thus, in England, among double-cut clovers are
the English Broad Red, Dorsett Marl, and Vale of Clwvd Early;
among the single-cut clovers, Montgomery, Cornish Marl, English
Late, and Vale of Clwyd Late. In the countries of continental Europe
also, several regional varieties occur, distinguished by the name of
the country or local area where the seed is produced, as Silesian,
Hungarian, French, Italian, Swedish. Claims of superiority are made
for all of these regional strains, and the evidence of comparative trials
shows that in most cases each such regional variety is superior to
others in the environment where it was developed. Some varieties,
CLOVER 1193
as the Mattenklee of Switzerland, are reported by investigators to
be especially distinguished by persistence.
These strains have not arisen as a result of conscious efforts toward
improvement of clover, but are rather the products of different en-
vironments acting on a highly variable plant. It seems probable also
that in some cases, as in England, natural crossing with the native
wild red clover may have affected the progeny of the cultivated form
first introduced from the low countries.
In North America regional strains are present as they are in Europe
and differ in productivity, winter hardiness, and disease resistance.
In the main, again, such characteristics have developed as a result
of the action of local environments. In many States these strains
have been grown continuously for 1 5 to 40 years without being mixed
with other seed and have in many cases proved themselves decidedly
superior. It must not be thought, however, that just because seed
was grown in a certain State it has taken on a special character.
A given lot of seed may represent one generation or many, and the
trade names "Ohio", "Michigan", etc., have little significance.
Improvement Work in the United States
Definite attempts at the improvement of clovers are of relatively
recent origin. In the United States studies looking toward the
selection of a superior red clover have, at one time or another, been
started at several State agricultural experiment stations, but, with
the exception of the Tennessee anthracnose-resistant strain, such
work has never been brought to fruition. The Kentucky station
has found a superior strain that is called Kentucky 101, but it did
not result from conscious selection but rather is an old stock grown
for many years under the same environmental conditions. Similar
valuable stocks exist in other States and can doubtless be made the
basis for future breeding work.
In 1906 the Tennessee Agricultural Experiment Station selected a
red clover resistant to the attacks of the fungus Colletotrichum tri-
foliiS. M. Bain (fig. 2). Here again the form arose through the
elimination of susceptible plants — man aided by seizing the oppor-
tunity to preserve a character brought out by the environment.
The same process of selection, with perhaps less conscious human
aid, has probably taken place elsewhere, since lines of long standing,
highly resistant to this disease, are found in Kentucky and Virginia.
In 1928 the United States Department of Agriculture, through the
cooperation of the State agricultural experiment stations, began a
thorough search for red clover stocks that had been grown con-
tinuously on the same farms or in the same communities for periods
of 10 years or more without the introduction of seed from outside
sources. Approximately 75 strains or lots were secured, many of
which had been grown for a continuous period of 40 years. These
were planted in small observation plots, in cooperation with the
Kentucky, Ohio, and Iowa Agricultural Experiment Stations. As a
result of these studies and previous observations on the adaptation
of foreign and regional strains of red clover, three regions of adapta-
tion have been recognized in the humid eastern part of the United
States, namely, the southern, central, and northern.
138004°— 37 70
1194
YEARBOOK, 1937
The chief limiting factor to which the plants must become adapted
in the southern region is disease, such as that caused by southern
anthracnose (Colletotrichum trtfolii). In addition the plants must be
able to survive frequent great changes of temperature during the
winter months, and high summer temperatures. This southern
region is composed of the States of Tennessee, Kentucky, and Mary-
Figure 2. — Strains of red clover resistant and susceptible to southern anthracnose,
caused by .Colletotrichum trifolii: A, Tennessee anthracnose-resistant strain; B, Italian
red clover. Arlington Experiment Farm, Arlington, Va.
land; the piedmont area of North Carolina and Virginia; parts of
New Jersey; the southern parts of Ohio, Indiana, and Illinois; and a
section of Missouri.
The central region includes the territory north of the southern
region to approximately the latitude of the Illinois- Wisconsin bound-
ary. Red clover adapted to this region must be disease-resistant
and winter-hardy, since low temperatures with little snow protection
are often met.
The northern region extends from the Wisconsin-Illinois line to the
Canadian border. In this region no serious diseases are encountered,
but the plants must be capable of tolerating a long period of dormancy,
which at times may be accompanied by very low temperatures.
Throughout the three regions attacks of the powdery mildew
fungus (Erysiphe polygoni DC.) and the potato leafhopper (Empoasca
jabae Harr.) occur regularly with fluctuating intensity. In general
the injury produced by the clover root borer (Hylastinus obscurus
Marsham) is one of the principal causes of red clover killing-out
during the second winter. In each of these regions the severity of
the adverse factors varies from season to season and according to
location.
After several years of study of the old strains in the central region
of the red clover belt, superior strains were selected as a basis for
CLOVER
1195
breeding studies. Several hundred plants of each of 10 strains were
studied, and it is of interest that the percentage of superior plants
in these strains ranged from 22 to 58, indicating the need of im-
provement.
In cooperation with the Kentucky station, seed of Tennessee
anthracnose-resistant and Kentucky 101, two superior strains, was
planted under controlled conditions, and the plants were artificially
Figure 3. — Resistance of red clover to the powdery mildew disease, caused by Erysiphe
polygoni: a. Seedling plants from commercial seed, covered with mildew; b, seedling
plants from mildew-resistant lines. University of Wisconsin, Madison, Wis., 1935.
inoculated with spores of southern anthracnose (Colietotrichum trifolii).
In these tests the percentage of resistant plants of Kentucky 101 and
of Tennessee anthracnose-resistant were, in 1925, 57 and 41, respec-
tively, while only 10 percent of the plants of an old strain from Wis-
consin remained alive.
In cooperation with the Wisconsin station, studies are in progress
to develop lines resistant to powdery mildew (Erysiphe polygoni).
Several fines have been developed that are resistant to two physiologic
forms of the fungus (fig. 3). Both self-fertile and self-sterile mildew-
resistant lines have been developed, but all of these are lacking in
vigor and require further selection and hybridization.
1196 YEARBOOK, 1937
Investigations on the improvement of red clover are in progress at
the Minnesota, Pennsylvania, Tennessee, Indiana, New Jersey, and
Idaho stations, and at the Kentucky, Wisconsin, and Illinois stations
in cooperation with the United States Department of Agriculture.
Improvement Work Outside the United States
Attempts to develop improved clovers are being made in nearly
every country in Europe and also in Australia and New Zealand.
In Canada two double-cut forms and two single-cuts are the result
of deliberate selection. The Ottawa selection, the result of a mass
selection process begun by the late M. O. Malte and carried forward
for many years by the late R. I. Hamilton, is claimed to be of superior
winter hardiness and is now coming into general use in Ottawa. An
early or double-cut strain, called the Dollard, of superior winter
hardiness, has been produced by J. N. Bird at MacDonald College,
Quebec.
The Altaswede red clover, selected by G. H. Cutler from a Swedish
strain, is said to be widely used in Alberta, but being a smooth clover
it is not satisfactory for use in the eastern United States. The Man-
hardy, another smooth strain of single-cut, was selected at the
Manitoba Agricultural College by W. Southworth out of various
escaped and cultivated lines and is believed by Canadian authorities
to be the hardiest strain of red clover in Canada.
In England the firm of Sutton & Sons selected a clover the seed of
which was pure yellow instead of purple or yellow and purple. The
stock came from yellow seed picked out of Chilean red clover. The
effort to place the variety on the market was abandoned, however,
since it was found impossible to prevent crossing in the field, and the
purple color again appeared in the seed.
The firm of Gartons, Ltd., in England, began development work as
early as 1890, but nothing of value has resulted from these efforts
nor from the efforts of other private workers. Since the establish-
ment of the Welsh Plant Breeding Station, systematic work has been
undertaken on the study of red clover. Breeding of red clover under
the direction of R. D. Williams has been important. So far one im-
proved variety, S-123, has been offered to the public. This was
released in 1936 and is believed to be useful for 2- and 3-year meadows.
The following strains, built up through crossing various lines, are being
tested but have not been released: S-87, S-106, S-110, and S-141.
Work of a similar kind has been undertaken in the Irish Free State,
but results are not yet available. In New South Wales, Australia,
an effort is being made to select a more persistent type out of a local
strain known as Santhia. In New Zealand a strain known as Runci-
man's red clover is said to be truly perennial and of great value in
pastures.
Martinet, and later Lindhard, tried to produce a variety with a
short tube or corolla. Lindhard (1921) claimed that honeybees
visited this variety freely and that it produced seed abundantly.
In Denmark various selected strains have been introduced as being
more valuable than the local parent stocks. These are Otofte early,
semilate, and late. The Otofte late was selected from a local stram
of red clover. The strain called Otofte semilate was bred from
CLOVER
1197
Hersnap, another improved late clover used in Denmark. There is
also Tystofte 40, a late form, and others.
In Germany various attempts have been made at improvement,
notably at Bonn-Poppelsdorf, but no record has been found regard-
ing results. Among private breeders was A. Dreger, who commenced
his work in 1908 and produced violet-seeded and yellow-seeded
varieties. According to Nessler (1931) the only bred clover in use
in Germany is Original Lembke's red clover. This is an early red
clover developed by Lembke in Wismar.
In Sweden such local strains as Norrum, for dry conditions; Karaby,
produced by L. Karaby; and Mardal, said to be resistant to Selero-
tinia, have become lo-
cally established. The
experiment stations
have also introduced
Svalof Purebred red
clover, produced by H.
Witte, and Mercur red
clover, produced by N.
Sylven, both of these
strains being valued for
yield and resistance to
"Sclerotinia and Tylen-
chus. Mercur was de-
veloped by mass selec-
Figure 4. — Longitudinal section of a red clover flower,
showing how anthers and style lie in the keel. (From
Stebler and Schroter, The Best Forage Plants, pi. 24,
fig. 2.)
tion'from a local strain called Spannard. Weibwell's Smaragd, out of
a Finnish local strain, and Gota Red, out of middle Swedish strains,
are also in use. The improvement work in Sweden has been carried
on by mass selection following intercrossing of various Swedish strains,
or by mass selection out of a single strain.
F. Chmelar, of Brno, in correspondence, advises that original
Dregers, out of Bohemian stock, and Mattenklee Rekord, selected
by K. Holy out of Swiss Mattenklee, are bred varieties grown in
Czechoslovakia.
In the Union of Soviet Socialist Republics special attention has
been paid to native strains of wild red clover. These wild strains
are said to vary in earliness, winter hardiness, production of after-
math, leanness, and resistance to disease. The opinion is held by
Lissitzyn and certain other Russian workers that these wild red
clover strains rather than selections from existing cultivated forms
should be made the basis of improvement.
Fertility and Pollination Relationships
Red clover heads are composed of from 50 to 150 florets, which in
themselves are complete units of reproduction. The florets develop
and open in an ascending order from the base to the top of the head.
The pistil is usually curved, the stigma extending beyond the anthers,
though florets have been found in which the style was greatly short-
ened, thus placing the stigma deep in the corolla tube (fig. 4). The
ovary of red clover has two ovules, one normally developing upon
fertilization and the other aborting. Plants have been found with
a high percentage of pods having two seeds.
Il'iii
YEARBOOK, 193 7
The anthers shed their pollen in the bud stage shortly before the
floret or individual flower of the head opens. At this stage the
pollen does not scatter freely. After the floret is open the stamens
and pistil remain in the keel, and the pistil becomes exposed only
after the floret is tripped. When the pressure causing the tripping
is released, the stamens and pistil return to the keel unless the floret
is ruptured. Fertilization occurs from 18 to 50 hours after pollina-
tion, the time depending on the temperature. When the atmospheric
temperature is high, fertilization
occurs much earlier than when it
is cool. The degree of success of
pollination can be approximately
determined 2 to 3 days after fer-
tilization.
Self-sterility in red clover has
generally been recognized since
Darwin caged plants to exclude
bees. The more recent studies of
Fergus of Kentucky, Kirk in
Minnesota, and Williams in
Wales have clearly established
the fact that nearly all the plants
are self-sterile. However, lines
have been established that are
homozygous or pure for self-fer-
tility, and Johnson in Minnesota
has mbred one line for nine genera-
tions without materially decreas-
ing the self-fertility. One of Fer-
gus' self-fertile lines maintained
its self-fertility for six generations,
after which the line was lost.
Self-sterility in red clover is
due to the slow growth of the
pollen tube in the style, the ovules disintegrating before the generative
nucleus reaches the egg. Kecent investigations by Williams (fig. 5)
in Wales indicate that this phenomenon is controlled by a series of
many sterility alternative genes or allelomorphs. Whenever the
same sterility factor is present in the pollen and in the female plant,
growth of the pollen tube is inhibited. He has also shown that in
self-fertile lines of red clover the presence of a noninhibitory self-
fertility factor or gene permits the pollen tube to grow at the same
rate as it does in the case of pollen from an unrelated plant.
Self Fertility
It is true that upon self-fertilization many red clover plants do
produce a few seeds, but there is a distinct incompatibility in the
succeeding progeny and the line cannot be maintained beyond the
second or third generation. This phenomenon may be called pseudo-
self-fertility as distinguished from true self-fertility.
Self-fertilization in red clover is accompanied by a decided decrease
in vigor of the plants. This decrease is most pronounced in the first
Figure 5.— K. D. Williams, Welsh Plant
Breeding Slation, Aberystwyth, Wales, who
has devoted much attention to the subject
of fertility and sterility of red clover.
CLOVER 1199
and second generation and differs in different lines. Apparently
Johnson's inbred line in Minnesota lias maintained more vegetative
and reproductive vigor that any other.
The number of true self-fertile plants in red clover is relatively
small. Out of many hundred self-pollinations only a few self-fertile
lines have been secured, though a large number of pseudo-self-fertile
lines have been found. In connection with red clover breeding
studies in the Department of Agriculture, from a spaced population
of approximately 4,000 plants, 500 superior open-pollinated plants
were selected,* each of these 500 plants was self-pollinated, but not a
single true self-fertile progeny was obtained.
Pollination
The structure of the red clover floret prevents cross-pollination by
wind, since the anthers and pistil remain enclosed in the keel unless
artificially tripped (fig. 4). Under natural conditions pollination is
done by insects, nearly all of which are bees (order Hymenoptera).
The bumblebees (Bombus) and the honeybees (Apis) are the prin-
cipal pollinators, although at certain times and places bees of other
genera, such as the ground bees (Tetralonia and Melissodes) and the
leaf -cutter bees (Megachile), contribute to cross-pollination.
Bees visit the red clover floret for nectar and pollen or both, tripping
the florets and transferring pollen from plant to plant, thus constantly
maintaining the condition of mixed inheritance in the species. Other
insects, such as moths, are constantly seen on red clover heads, but
they do not come in contact with the pollen and therefore do not
effect cross-pollination.
There has been considerable controversy as to the extent to which
pollination can be accomplished by honeybees. Discussion has cen-
tered upon the fact that the tongue of the honeybee is not long enough
to reach the nectar. The literature on this subject is voluminous and
cannot be reviewed here. More recent investigations clearly indicate
that honeybees visit red clover principally for pollen and seldom
obtain nectar, but regardless of what is obtained, pollen is transferred
and cross-pollination is effected.
Breeding Methods
In the breeding of red clover inherent difficulties exist that have
greatly retarded advancement in the improvement of this crop. These
factors are chiefly the small size of the red clover floret and the fact
that the plants are self-sterile. In general the method followed in the
past in breeding for an improved variety of red clover has been to start
with a valuable local stock and attempt to secure a better strain by
mass selection of the most desirable types. Because of the necessity
for cross-pollination, red clover is in a hybrid condition and the
progeny of selected plants will continue to produce a certain per-
centage of undesirables. These may be eliminated in some cases by
continued selection and in others by unfavorable factors in the environ-
ment. The latter is the case with the anthracnose-resistant strains
produced in the southern region of the red clover belt and the winter-
hardy strains of the northern region, since they are naturally subjected
to disease or to severe winter conditions. All varieties successfully
1200 YEARBOOK, 1937
established in the United States and Canada to date have been
developed by the aid of this natural selection.
Special inoculation beds with favorable conditions for development
of the disease organisms have proved to be advantageous in studies on
disease resistance. Experience has shown that field inoculations are
not always successful, and there is always the possibility that sur-
viving plants may have escaped inoculation rather than that they are
resistant. The worker must also consider the susceptibility of the
host as related to age and environment.
In details, the method of making crosses varies with the individual
investigator. Toothpicks, camel 's-hair brushes, cards, and crooked
needles have all been successfully used for the transfer of pollen.
Since most of the red clover plants are self-sterile, reciprocal crosses
can readily be made without the emasculation or removal of anthers
necessary with many plants.
Bumblebees from which pollen has been washed have been success-
fully used by Williams for cross-pollination, and this method offers the
distinct advantage of securing large numbers of seeds in any specific
cross. Lindhard caught queen bumblebees in the spring and developed
the broods in special boxes that could be moved to cages in which the
plants were enclosed. Natural nests have been transferred to artificial
domiciles and moved about at will in studies by the Bureau of Plant
Industry. Honeybees have been successfully used when many plants
were to be cross-pollinated.
Williams (17), 1 of the Welsh Plant Breeding Station, follows three
methods: (1) Strain building — selecting superior plants of old stocks
and combining them by controlled crossing; (2) brother-and-sister
matings — combining desirable sibs of the same families for several
generations, ehminating plants with undesirable recessive characters
after each crossing, and later outcrossing to unrelated families that
have been sib-crossed; (3) dialed crossing — intercrossing several lines
with one another to determine the combinations producing the best
progenies, followed by intercrossing among such progenies to form a
new strain.
The development of mildew-resistant lines in Wisconsin has resulted
from selections made from artificially inoculated beds. The progeny
of these selections were sib-crossed and selfed to secure Tines
homozygous or pure for mildew resistance. The crossing of unrelated
lines resistant to mildew is in progress to restore vigor.
The results of studies by Williams and by the Bureau of Plant
Industry clearly show the effects of sib-crossing. Loss of vigor with
succeeding sib crosses for several generations is usually evident.
Whether full vigor can be restored and maintained by combining a
limited number of unrelated lines remains to be proved. Experience
has shown that the growing of large populations of spaced plants is
essential if progress is to be made. While controlled crossing may be
accomplished in the field, a greenhouse is a valuable asset. The neces-
sary manipulation can be more easily performed and a higher per-
centage of seed may be expected in the greenhouse than in the field.
The isolation and use of self-fertile lines in the breeding of red
clover, while discredited by some investigators as offering little promise,
'Italic numbers in parentheses refer to Selected References, i). 1211.
CLOVER 1201
has the distinct advantage of developing plants that are pure (homo-
zygous). The loss of vigor by making sib crosses for several genera-
tions is practically as great as that resulting from selfing, and self-fertile
lines are more readily maintained. The selfing of one head per plant
is sufficient to determine whether it is self-fertile.
Isolation of Breeding Material
In Europe the problem of isolation of stocks in the early stages of
development has been met by planting in an isolated field among other
plants. Lang planted his red clover in the midst of a field of other
plants blooming at the same time so that the bees might work on these
plants first and thus have any foreign red clover pollen cleaned off
before they arrived at the red clover plants. Dreger isolated his
breeding stock in a field of Vicia villosa. By this means he claims to
have produced a strain of red clover with uniformly violet seed.
Williams and Evans found that contamination by extraneous pollen
depended on two factors — (1) the distance separating the bred strain
from other red clover plants and (2) the profusion with which the
strain flowers. In their experiments it was found that when there
was little bloom on the pure strain the percentage of contamination
was great, no matter how well isolated the plot. On the other hand,
with abundant bloom relatively little contamination occurred even
when the plot was not well isolated .
WHITE CLOVER
White clover, a common inhabitant of lawns, pastures, and roadsides,
is widely distributed in every continent of the world, with a natural
distribution probably as great as that of any other plant of the legume
family. Moist and cool situations are its most favorable habitat
and under such conditions growth is continuous. Though it is be-
lieved not to be indigenous to North America, it was brought over
very early and the year of its introduction is not known.
The white clovers of agricultural value have been grouped as wild,
cultivated or Dutch, and Giant or Ladino. Five other varieties are
mentioned but are only of botanical interest.
In form these groups differ chiefly in plant size, the English wild
white clover being smaller in all vegetative parts than the Dutch,
and this again smaller than the Ladino. In England the wild white
clover differs also in being more persistent than the Dutch white
clover, which is often short-lived. As a group, the native or wild
white clover is distinguished from the Dutch white clover and the
Ladino white clover by the presence of a cyanophoric glucoside.
This is an organic substance present in many herbage plants and which
in the course of digestion forms hydrocyanic acid. The quantity
present in white clover is small and harmless. The more persistent
plants have a high glucoside content, while the short-lived Dutch
and the Ladino have but little or none.
Origin of Varieties and Forms
The development of varieties and strains of white clover has resulted
from the action of environment on this variable species. Thus in
the United States it is possible to distinguish the strain produced from
1202 YEARBOOK, 1937
Louisiana seed from that produced from Wisconsin seed, the Louisi-
ana strain being more persistent under summer conditions but slightly
less winter-hardy than the Wisconsin strain.
White clover was introduced into New Zealand from England, but
the best white clover produced as wild white in New Zealand today
differs from the wild white of England in its larger growth.
In New Zealand, where intensive work has been done with white
clover, Bruce Levy has distinguished four strains of New Zealand
white clover, differing in productivity and persistence, the best
strain being like English wild white clover and the least satisfactory
form like Dutch white clover. In Denmark two distinct varieties
of white clover are grown, Mors0 and Stryn0. Of these the Mors0
appears to be the more permanent and the better seed producer,
but the Stryn0 is the better yielder of herbage. In Sweden a very
persistent strain called Svea has been produced at Svalof and is now
on the market. In Finland the Tammisto strain, which has proved
hardy and a good yielder, has been developed from native Finnish
stocks.
Though no critical studies have yet been made, observations indi-
cate that the white clover growing in old pastures in the northeastern
United States has the same growth habit and persistency as the
English wild white clover. A common descent may be presumed,
since white clover was brought to this country by the early settlers.
Ladino white clover was first discovered in northern Italy, but its
exact origin is unknown. It does well under irrigation but has not
been successfully established in the eastern United States.
Breeding Investigations
The difficulties experienced in the breeding of white clover are
similar to those in the breeding of red clover, and the same procedure
is applicable. White clover, like red clover, is extremely variable in
leaf size, color, and markings; flower and seed color; size of runners;
and persistence. Combinations of one or more characters in indi-
vidual plants have been observed from time to time. In many cases
these have been perpetuated by vegetative propagation, and in a
few cases strains have been developed that are homozygous for cer-
tain characters. All the strains to which reference has been made
are the result of natural selection with only incidental help from man.
At present special breeding work is being conducted at the Weraroa
station in New Zealand, where the Weraroa strain was isolated as
no. B-95. It is said to be truly perennial and a good yielder. At
the Welsh Plant Breeding Station a variety, S-100, was released in
1936 and is described as being more productive than commercial white
clover and as lasting longer. It was produced from Dutch, New
Zealand, and wild white clover and is intended for use in 1- to 3- year
meadows. Another variety, S-99, has not yet been released.
Breeding work is also being carried on at various stations in Germany,
Denmark, Czechoslovakia, and Sweden.
Experiments by Williams (17), Erith (S), and others have clearly
shown that self-sterility in white clover is not so marked as in red
clover but is the result of a similar phenomenon. The possibility of
developing self-fertile lines is, therefore, slightly greater. A pro-
CLOVER 1203
nounced reduction in vigor results from inbreeding, with the appear-
ance of dwarf and chlorophyll-deficient seedlings and other recessive
characters.
OTHER TRUE CLOVERS
Crimson Clover
Crimson clover — the most important winter annual of the true
clovers — was first introduced in the United States in the early part of
the nineteenth century, and the Patent Office made a distribution of
the seed in 1855. This species is self-fertile and is less variable than
the clovers previously discussed. The florets are not self-tripping and
for maximum seed crops require insect visitation.
Several varieties of crimson clover are recognized, differing in date
of bloom and in color of the flowers. Vilmorin-Andricux & Cie., of
Paris, refer to Extra Early Crimson, Early Crimson, Late Crimson,
Very Late White Flowering, and Extra Late Crimson Flowering. A
difference of 4 to 5 days in time of maturity is shown between each of
these varieties in the order named. An early white variety is also said
to exist.
In the United States a local strain, developed in northern Georgia
and known locally as Pitt's clover, is said to have given better results
in Georgia than commercial seed.
Alsike Clover
The first recorded introduction of alsike clover into the United States
occurred about 1839, when the Genesee Farmer, an agricultural journal,
made a small distribution. No recognized varieties exist, but regional
strains give varying results. In Sweden the native strain yielded more
than that from Silesia or that from North America. In preliminary
studies in the United States, differences of this sort have been noted.
The plants are generally self -sterile, though Wilson in Minnesota has
shown that self -fertility exists; loss of vigor follows inbreeding.
Subterranean, Berseem, and Persian Clovers
The clovers known as subterranean, berseem, and Persian are all
annuals, the first two distinctly winter annuals, and are used for hay
or grazing. Subterranean clover is little used in the United States.
In Australia several strains of subterranean (Trifolium subterraneumli.)
differing chiefly in date of maturity, are known, and in Egypt and else-
where three or four distinct strains of berseem (T. alexandrinum L.)
are recognized. Strains of Persian clover (T. resupinatum L.), dif-
fering in maturity, have been selected by workers in Turkistan. In
none of the other true clovers are strains recognized, and no special
improvement work, so far as known, is being carried on with these.
SWEETCLOVER
Although a relatively new crop, sweetclover offers one of the most
promising possibilities for forage improvement. The different species
appear on the whole to be self-fertile, although some are not self-
pollinating. Large numbers of honeybees visit the florets, effecting
a certain amount of cross-pollination and thus increasing variation
among the plants.
1204 YEARBOOK, 1937
In general, the sections where sweetclover is principally grown are
the north-central region and the Great Plains States. This territory
may be divided into two areas of adaptation — (1) the area east of the
Nebraska-Iowa boundary and (2) the Great Plains States. In the
eastern region resistance to a disease complex is of first importance in
connection with the development of more palatable late-maturing
strains for pasture. In the Great Plains States diseases as yet are of
minor importance, but drought-resistant palatable strains for hay and
pasture are needed. A coumarin-free strain would be desirable every-
where, since the presence of coumarin affects the palatibility of the
herbage and, as shown later, is probably related to the development of
a toxic substance in spoiled hay.
The sweetclovers grown in the United States belong to the genus
Melilotus. They include white sweetclover {M. alba), yellow sweet-
clover (M. officinalis), and sourclover (M. indica). Redfield yellow,
an early introduction of the United States Department of Agriculture,
appears to be M. suaveolens Ledeb., though in many respects it re-
sembles M. officinalis. The first species mentioned includes both
biennial and annual forms, while M. indica is an annual, and of
M. suaveolens and M. officinalis the biennial form only is known.
Varieties
Of the white sweetclover group, the Grundy County, Hubam,
Arctic, Alpha, Iowa Late White, Ohio Evergreen, and Madrid White
varieties have characteristic qualities and are in use to a greater or
less extent. Grundy County White was first noted in Grundy
County, 111., in 1917, but is of unknown origin. It is early, of erect
habit, with slender stems, and it is not so tall as the common biennial
white sweetclover. Arctic was named by J. Bracken at the University
of Saskatchewan, Saskatoon, Canada, and was derived from a Siberian
importation brought in by N. E. Hansen. It is especially noted for
winter hardiness and behaves as a dwarf variety in the central part
of the United States, although making a much greater growth in
Canada.
Madrid White, introduced by the United States Department of
Agriculture through seed received from the Botanic Garden in Madrid,
Spam, is a large-growing variety characterized by early seedling
vigor and tolerance of the first year's growth to frost. Hubam is
an annual mutation from Melilotus alba and was first brought to
general attention by H. D. Hughes, of Iowa, in 1917. This variety
resembles common biennial white sweetclover, except that it blooms
and seeds freely the season of planting and does not survive a second
year.
Alpha sweetclover is a variety developed by L. E. Kirk at the Univer-
sity of Saskatchewan. The first plants were found in a field of Arctic
sweetclover in 1924, and Kirk developed the variety by a process
of inbreeding and selection. The plants of the Alpha variety
branch profusely at the crown, the slender stems being leafy and
resembling alfalfa. It is a dwarf variety in the central part of the
United States and is not adapted to that region.
Iowa Late White is a large-growing, late-maturing selection made
by the late F. S. Wilkins, in 1935, at the Iowa Agricultural Experiment
CLOVER
1205
Station, from a lot of seed secured from an Illinois farmer. Ohio
Evergreen is similar in growth habits and maturity to the Iowa
Late White. Selections of this variety were made by J. B. Park,
of the Ohio Agricultural Experiment Station, as a result of several
years of mass selection of desirable types secured from roadside
plants. A selection made by the Illinois Agricultural Experiment
Station and called Illinois No. 8
is another late-maturing uniform
strain selected from wild plants.
Selections made by Brink at the
University of Wisconsin were de-
veloped in the effort to improve
disease resistance. Hayes, John-
son, and Doxtater, of the Minne-
sota station, have made selections
from Alpha and commercial white,
resulting in a strain called Minne-
sota No. 1 and a strain of Alpha
that is more disease-resistant than
Alpha from Canada. In the Pa-
cific Northwest the growing of
sweetclover west of the Cascade
Mountains was unsuccessful until
the development of a strain resist-
ant to what is believed to be stem
rot. This variety was developed
by H. A. Schoth, at Oregon Agri-
cultural Experiment Station, over
a period of years, by growing suc-
cessive generations in thesamesoil,
allowing the disease organism to
eliminate the susceptible plants.
Less attention has been given to the selection of varieties from
yellow sweetclover (Melilotvs officinalis) than from white sweetclover.
In general, the varieties of yellow sweetclover are less productive and
mature earlier than those of white sweetclover. Many varieties,
such as Albotrea, Madison County or Switzer, and St. Louis Valley,
are very much like the commercial yellow. Zouave, developed at
the University of Saskatchewan, is more erect the first year than the
commercial yellow and has seed that is densely mottled with purple.
Daghestan Yellow, introduced from the Province of Daghestan,
Transcaucasia, and having large and rounded leaflets, appears to be
a form of M. suareolens.
Redfield Yellow, a variety received by the Department of Agri-
culture from Manchuria in 1915 as Melilohis alba, but which later
proved to be a yellow form, was developed and named at the Depart-
ment's forage-crop field station at Redfield, S. Dak. The fact that
Redfield Yellow crosses readily with M. alba while M. officinalis does
not cross with alba and the further fact that Redfield Yellow does
not cross with known varieties of M . officinalis appear to confirm the
classification as M. suareolens. Madrid Yellow, introduced by the
Department from seed received from the Madrid Botanical Garden,
Figure 6. — L. E. Kirk, Dominion agroatol-
ogist, Dominion of Canada Experimental
Farm, Ottawa, Canada, who has pioneered
in the genetics of sweetclover.
1206
YEARBOOK, 1937
has vegetative characteristics similar to those of Madrid White,
previously described. The character of early seedling vigor
makes both the Madrid Yellow and the Madrid White supe-
rior for Great Plains conditions, where early establishment is of
the iitmost importance. In addition to the above-mentioned
varieties of both white and yellow sweetclover, other local strains
Figure 7. — Segregating sweetclover line, showing branched dwarf character in center,
compared to normal growth on each side. Arlington Experiment Farm, Arlington, Va.,
1936.
are in existence, developed largely by the continued growing of
strains over a period of years.
Breeding Work in North America
Definite breeding work has progressed more in Canada under the
direction of L. E. Kirk than elsewhere (fig. 0). Kirk has made ex-
tensive studies on pollination, selfing, and crossing. Improvement
work in Canada has been directed toward "the production of winter-
hardy, fine stemmed, leafy, disease resistant and more palatable sorts."
Three methods are used — (1) isolation of desirable plants or of plant
groups so as to provide for immediate increase of a superior form; (2)
isolation of desirable forms through selection within inbred lines; and
(3) hybridization, to combine the desirable features of the best inbred
lines (fig. 7). Studies of variations in coumarin content of individual
plants have given promising results. Lines have been selected that
CLOVER 1207
appear to be approaching homozygosity for low and for high coumarin
content.
The Wisconsin station, in cooperation with the Department of
Agriculture, has been studying the relationship between coumarin
and palatability and toxic properties of spoiled sweetclover hay.
Results indicate that coumarin is intimately connected with the toxic
principle and is one of the important factors in the palatability of
sweetclover for pasturage. Hybridization experiments are in progress
within and between lines of Melilotus alba, M. suaveolens, M. officinalis,
M. dentata Pers. , and other species.
At the Minnesota station various lines have been inbred for 4
years. In agreement with the work in Canada, selfing has not
resulted in any material reduction in vigor in either common biennial
white clover or Alpha. The development of a variety of low coumarin
content and high yield is the objective of this work.
In Kansas, Washington, and Texas, and at Guelph, Canada, selec-
tion of desirable sweetclover lines is in progress. The Nebraska and
Illinois stations, in cooperation with the Department, have estab-
lished nurseries for selection and breeding looking toward the develop-
ment of varieties having superior value. In West Virginia various
selfed lines are being grown with a view to securing one that will
thrive at a higher acidity level than that at which sweetclover now
does well. The Idaho station reports the development of a sweet-
clover having purple seeds, a crown similar to alfalfa, and nonshatter-
ing pods. A report for 1934 stated that none of the purple-seeded
types proved homozygous for this character and that the plants were
segregating for numerous other characteristics.
Breeding Work Abroad
The Russians have been interested in the breeding of sweetclover,
especially at the Institute of Plant Breeding, at the Black Soil Regional
Plant Breeding Center, at the Maikop and the Detsko-Selo stations
in the north Caucasus, and at Saratov. Both commercial varieties
and native wild strains are said to be used, various forms having been
isolated to serve as breeding stock. Attention is being paid to
variations in coumarin content.
At the Kaiser Wilhelm Institut fur Zuchtingsforschung, Munche-
berg, Germany, under the direction of M. Ufer, many thousands of
plants from different sources have been grown and studied for relative
freedom from coumarin. Of these, 51 individuals were selected.
Among the species studied were Melilotus alba, M. officinalis, M.
wolgica Poir., M. dentata, and M. indica. This work was reported in
1934, but no later information is available.
Pollination and Fertility
Pollination of sweetclover under natural conditions is effected
principally by honeybees, except insofar as the species, varieties, or
individuals are spontaneously self-fertilized. Various workers have
studied this problem, but only a brief summary of the information as
given by Kirk and bv Kirk and Stevenson can be given here. While
Melilotus alba is generally highly self-fertile, three groups have been
recognized: (1) Plants in which nearly all florets produce seed without
1208 YEARBOOK, 1937
manipulation — spontaneously self-pollinated and self -fertile; (2) plants
that do not produce seed without manipulation — self-fertile but not
self -pollinating; and (3) self-sterile plants. The varieties of M.
officinalis are not spontaneously self-pollinated, but are not completely
self-sterile as is commonly thought. When the stigmatic surfaces are
scratched in selfing, some seed is formed, though the proportion is not
so great as when the florets are open-pollinated. The Redfield Yellow
variety is spontaneously self-pollinated and self-fertile, and this is
also the case with many lines of M. dentata.
GENETIC STUDIES IN CLOVER 2
With the advent of more extensive genetic studies of plants, an
occasional investigator became interested in the inheritance of
particular characters of red clover. For the most part, however,
the inherent difficulties occasioned by the self-sterility of the species
and the manipulation of the florets in making crosses discouraged
the initial efforts. Until recent years the published reports of
such investigations were principally confined to general statements
of what appeared to be evident.
Reo Clover
Flower and seed-coat color of red clover were the basis of most of
the early observations. De Vries (14) described the selection of a
line that in the fifth generation had a large proportion of leaves com-
posed of seven leaflets. He also reported that white flower color was
recessive to red, being inherited in a simple ratio.
In 1903 Fisher likewise developed lines in which 85 to 100 percent of
the progeny had yellow seed coats and another line in which 86 to 99
percent had dark-violet seed coats. In 1912 Kajanus (6) studied a
blue-flowered red clover plant and reported that blue was recessive,
being inherited in approximately a 15:1 ratio. He also stated that red
flower color was dominant over white. In 1921 Witte (20) reported
finding a white seeded red clover in which the white seed was associated
with white flower. When this plant was crossed with those having
yellow seed, the F2 generation segregated in a 3:1 ratio.
In any large population of red clover plants, many have a crescent-
shaped leaf marking while in others no markings are evident.
Gmelin's (5) studies in 1916 showed that the presence of leaf markings
was dominant. His work also confirmed the report of Kajanus (<?)
that white flower color was recessive to red. Fruwirth also studied
flower color, counting the number of plants producing white and red
flowers. The more recent work of Wexelsen (16) on the presence and
size of leaf spot, leaf color, anthocyan pigment and its presence in
stems and stipules, flower color, and resistance to mildew indicates an
increasing interest in the inheritance of characters of red clover.
Nijdam (11) also investigated incompatibility, seed-coat color, flower
color, chlorophyll difference, sterile stamens, and dwarfs. These
studies include the occurrence, variation, and segregations of crosses.
Segregation ratios were reported.
With the establishment of the Welsh Plant Breeding Station an
orderly investigation of red clover breeding began. Experimental
' This section is written primarily for students and others professionally interested in breeding or genetics.
CLOVER 1209
proof by Williams and Silow (19) of sterility and fertility relationships
of red clover, mentioned in a preceding section, affords a basis on
which genetic studies may proceed soundly. The comprehensive
studies of Williams (18) on flower color clearly show the presence of
additional epistatic recessive factors with linkage relationships to the
sterility genes, a condition not unexpected when the characters of
large populations are critically examined. Besides the characters
mentioned above, many investigators have observed the occurrence
of dwarf forms, chlorophyll-deficient seedlings, abnormal flower-head
development, and other variations.
Cytology of Red Clover and Other Trifolium Species
With the increased interest in cytological study as related to
genetics, and its apparent usefulness in interspecific hybridization,
studies on chromosome number and morphology have been undertaken
by a few investigators, notably Bleier (1) Karpechenko (Karpets-
chenko) (7), and Wexelsen (15). In the majority of cases these
investigators agree on the number of chromosomes, particularly in
the most important species. Differences of opinion exist, however,
on some points, and additional studies, with improved methods, are
needed for a clearer understanding. The basic numbers of chromo-
somes are seven and eight, with multiples thereof, but species belonging
to a given subsection of the genus Trifolium do not always have the
same number of chromosomes. Ascherson and Graebner record
various alleged hybrids as having been found in Europe, but experi-
mental interspecific crossing has invariably been unsuccessful. A
table of chromosome numbers of all species of Trifolium for which data
are available is presented in the appendix.
White Clover
Genetic studies on the inheritance of different characters of white
clover are in the developmental stage. In a preliminary report on a
few crosses made between several varieties, Erith (3) states that leaf
color and flower color are inherited as a single-factor difference. Nor-
mal green leaves are dominant to purple, and pink flower color is
dominant to white. Cytological studies by Wexelsen (15) on two
varieties — English wild and Ladino — show no difference in the
chromosome numbers. Those of Ladino are, however, much larger,
though considerable variation in this regard exists between plants of
the English wild white clover. In crosses between varieties, the
chromosome size of the Fi generation was found to be intermediate
between those of the parents.
SWEETCLOVER
As indicated in the preceding section, improvement of sweetclover
has been principally concerned with the introduction and trial of
various sweetclovers from the Old World. The occurrence of natural
hybrids and mutations has stimulated interest in characters and their
inheritance.
In breeding sweetclover, emasculation is necessary unless the female
parents carry a recessive character that may readily be determined in
the Fx generation . Kirk's water-suction method for greenhouse studies
138004°— 37 77 ++
1210 YEARBOOK, 193 7
and Savage's automobile vacuum method for field emasculation, as
described in the article on Alfalfa Improvement in this Yearbook, are
ingenious devices that have been successfully used. In view of the
numerous hazards in breeding work, the need of greenhouse facilities
cannot be overemphasized. A plant generation can be grown in the
greenhouse in the winter either by placing the young seedlings under
continuous light or by freezing seedlings a few weeks old and then
placing them under a long-day exposure. These methods have been
successfully used by Kirk in Canada and by Johnson in Minnesota.
Cytological studies are necessary for intelligent plant breeding,
particularly when interspecific hybridization is to be undertaken. The
studies of Castetter, Elders, Clarke, Smith, Fryer (4)> Chekov (Tsche-
chow), and Cooper all show that the diploid number of chromosomes
of the species studied is 16. The morphology of the chromosomes of all
the species investigated appears to be similar, although those of the
species of the subsection Campyloryiis are smaller than those of other
species.
The appearance of Hubam and of the Alpha form undoubtedly
stimulated inheritance studies. Smith concluded from his studies
that the annual character was dominant and counts of segregating
progeny indicated a close agreement of a 3: 1 ratio. Elders, Kirk (9),
and Clarke (2) have shown that the Alpha type is recessive to normal
and is inherited in a ratio of 3 : 1. Clarke also reports the presence of
a recessive spreading dwarf character and of two factors for pale-green
seedling. Linkage between pale green and spreading dwarf is evident.
Using the F2 and F3 lines developed from a natural hybrid between
Melilotus alba and M. suaveolens (Redfield Yellow), Kirk (8) reports
that the inheritance of flower color is in close agreement with a three-
factor hypothesis, two factors for cream, varying in intensity, together
giving yellow, and a third factor that inhibits the action of factors for
cream and yellow giving white. Segregations in several of the above
lines, however, indicate a deficiency of yellow plants. Reference to
seed-coat color has been the basis of determining whether seed is from
M. alba or M. officinalis. Various workers have considered the clear
seed coats of M. alba as a distinguishing characteristic differing from
those of M. officinalis in which a varying percentage of seeds are
flecked with purple. Kirk and Stevenson have reported the finding
of speckled seed coats in a line of Alpha (M. alba). Previous crosses
indicated that color markings are dominant over clear seed-coat color.
Kirk and Armstrong (10) also describe a mutation characterized by a
reduction of the size of leaf with a pattern dissimilar to normal. This
abnormality is also expressed in size and pattern of corolla. The plants
are dwarfed, self-sterile, and cross-sterile to pollen from normal
types.
The characters in sweetclover are as diverse as in other plants;
purple seed coats, green cotyledons, dwarfs, and chlorophyll-deficient
seedlings, germinable seed not needing scarification, and floret abnor-
malities have already been observed.
Interspecific Hybridization
The fact that all species of Melilotus have the same basic number
of chromosomes, supported by the occurrence of natural and artificial
CLOVER 1211
hybrids between species, has encouraged the belief that interspecific
hybridization may be successful. The reports of early botanists on
the occurrence of natural hybrids have been summarized by Schulz
(12) and later by Ascherson and Graebner in their systematic treatise
on the genus Melilotus. These authors mention hybrids between
M. alba and M. altissima Thuill, M. alba and M. officinalis, M. altis-
sima and M. officinalis, and M. officinalis and M. wolgica. The
authors describe these alleged hybrids as having characters of both
supposed parents, but genetic data on the supposed hybrids are
wanting. Kirk and Stevenson failed to obtain a single hybrid be-
tween crosses of M. alba and M. officinalis. In an experiment de-
signed to favor natural crossing between a line of M. alba and its
varieties and species of yellow-flowered sweetclovers. Kirk secured
one hybrid with cream-colored flowers. This is similar to hybrids
secured later from artificial crosses between M. alba and Redfield
Yellow. Furthermore, reciprocal crosses between Redfield Yellow
and Albotrca and between Zouave and Redfield Yellow failed to
produce a single hybrid. Natural hybrids of the same nature, in-
volving crosses between Redfield Yellow and M. alba, have been se-
lected by Garver at Redfield, S. Dak., and at Arlington Experiment
Farm, Arlington, Va. Sylven, in Sweden, reports a natural hybrid
between M. alba and M. officinalis, selected from seed secured from
Canada. It is possible that this hybrid may have arisen from the
cross between M. alba and Redfield Yellow or the reciprocal. More
recent work of Stevenson and Kirk (18) shows that hybrids can read-
ily be secured by artificial cross-pollination between M. alba (Alpha)
and M. suaveolens (Redfield Yellow). The evidence tends to the
conclusion that, while M. alba and M. officinalis and M. officinalis
and M. suaveolens are reciprocally sterile, M. alba and M. suaveolens
are reciprocally fertile. Compatibility varies, however, between
individuals, depending upon which species is used as the male or
female parent. In several cases crosses between M. alba and M. offi-
cinalis and between M. alba and M. dentata have resulted in the
development of pods and shrunken nongerminating seed. Efforts to
dissect out hybrid embryos at an early stage of development and
grow these to maturity in nutrient cultures have failed. Further
attempts at interspecific hybridization are in progress at several
places.
Intergeneric crosses between Melilotus, Medicago, and Trigonella
have been attempted by Fryer (4) and by Stevenson and Kirk (IS),
but without success.
SELECTED REFERENCES
(1) Bleier, H.
1925. CHROMOSOMENSTUDIEN BEI DER GATTUNG TRIFOLITJM. Jahrb. W]SS.
Bot. 64: [604]-636, illus.
(2) Clarke, A. E.
1931. INHERITANCE OP THE DWARF BRANCHING HABIT IN SWEET CLOVER.
Sci. Agr. 11: 326-332.
(3) Erith, A. G.
1924. white clover (trifolitjm repens l.). a monograph. 150 pp.,
illus. London.
1212 YEARBOOK, 1937
(4) Fryer, J. R.
1930. CYTOLOGICAL STUDIES IN MEDICAGO, MELILOTUS, AND TRIGONELLA.
Canad. Jour. Research 3: 3-50.. illus.
(5) Gmelin, H. M.
1916. PROEFNEMINGEN MET ROODE KLAVER. TWEEDE REEKS VAN ONDER-
ZOEKINGEN MET BETREKKING TOT DE ROODE-KLAVERVEREDELING.
Cultura28: 414-430.
(6) Kajanus, B.
1912. tJBER DIE FARBEN DER BLUTEN UND SAMEN VON TRIFOLIUM
pratense. Fuhlings Landw. Ztg. 61: 763-776.
(7) Karpechenko, G. D. (Karpetschenko, G. D.)
1925. KARYOLOGISCHE STUDIEN UBER DIE GATTUNG TRIFOLIUM L. Trudy
Prikl. Bot. i Selek. Bull. Appl. Bot. and Plant Breeding.
14: [271] — 279, illus. [In Russian. Resume in German, p. 279.]
(8) Kirk, L. E.
1931. INHERITANCE OF FLOWER COLOUR IN A CROSS BETWEEN WHITE
BLOSSOM AND YELLOW BLOSSOM SWEET CLOVER (MELILOTUS ALBUS
DESK. X M. OFFFICINALIS (L.) DESR.). Sci. Agr. 11: 265-273.
(9)
1931. INHERITANCE OF DWARF BRANCHING HABIT IN A NEW VARIETY OF
SWEET CLOVER AND ITS POTENTIAL ECONOMIC VALUE IN BREEDING
Sci. Agr. 11: 315-325, illus.
(10) and Armstrong, J. M.
1934. A SINGLE FACTOR MUTATION IN MELILOTUS ALBA DESR. HAVING
MULTIPLE EFFECTS ON HOMOLOGOUS STRUCTURES. Canad. Jour.
Research 10: 787-792, illus.
(11) Nudam, F. E.
1932. kruisingen met trifolium pratense l. Genetica 14: [161]-278,
illus.
(12) Schulz, O. E.
1901. monographie der gattung melilotus. Bot. Jalirb. 29: [660]-
735, illus.
(13) Stevenson, T. M., and Kirk, L. E.
1935. STUDIES IN interspecific crossing with melilotus, and in
INTERGENERIC CROSSING WITH MELILOTUS, MEDICAGO, AND trig-
onella. Sci. Agr. 15: 580-589.
(14) Vries, H. de
1910. THE MUTATION THEORY; EXPERIMENTS AND OBSERVATIONS IN THE
OBIGIN OF SPECIES IN THE VEGETABLE KINGDOM. Transl. by
J. B. Farmer and A. D. Da,rbishire. v. 2, illus. Chicago.
(15) Wexelren, H.
1928. CHROMOSOME NUMBERS AND MORPHOLOGY IN TRIFOLIUM. Calif.
Univ. Pubs., Agr. Sci. 2: 355-376, illus.
(16)
1932. SEGREGATIONS IN RED CLOVER (TRIFOLIUM PRATENSE L.). Hereditas
16: 219-240, illus.
(17) Williams, R. D.
1931. METHODS AND TECHNIQUE OF BREEDING RED CLOVER, WHITE CLOVER,
and lucerne. Imp. Bur. Plant Genetics, Herbage Plants
Bull. 3: 46-77, illus.
(18)
1935. GENETICS OF FLOWER COLOUR IN TRIFOLIUM PRATENSE L. 1. BASIC
white colour (factor c). Jour. Genetics 31: 431-450.
(19) and Silow, R. A.
1933. GENETICS OF RED CLOVER (TRIFOLIUM PRATENSE L.), COMPATIBILITY.
i. Jour. Genetics 27: [341J-362.
(20) Witte, H.
1921. EINIGE BEOBACHTUNGEN UBER DIE SAMENFARBEN DES ROTKLEES
und ihre erblichkeit. Sveriges Utsadesfor. Tidskr. 31: 257-
267. [In Swedish. German summary, pp. 264-265.]
CLOVER
1213
APPENDIX
Tabi.k ] . — Chromosome numbers of investigated species of the genus Trifolium
Bleicr
T. albopurpureum T. anil G
T. alexandrinum L
T. alpestre h
T. ambiguum M. Bieb
T. angustifollium h
7*. arvense L ___
T. badium Schreb
T. campestre Schreb. =7\ pro-
cumbent L ---
T. ciliolatum Benth
T. dkhotommn XL. and A
T. ftliforme L
T. fragiferum L
T.fucatum Lindl
T. fucatum virescens (Greene)
Wex _ -
T. glomeratum L._ _-
T. hybridum h..
T. incarnatum L
T. lappaceum L
T. lupinaster L
T. maritimum lluds
T. medium l L__ _ __
'48-49
Kar-
pet-
schen-
ko 2n
lfi
14
18
48
16
'80
Wex-
elsen
2«
Species
Bleier
T. mkroccphaium Pursh
T. minus Sm.a (dnbium Sibth) -
T. montanum L
T. obtusiflorum Ilook
T. obtmifiorum majus (Greene)
Wex
T. ochroleucum lluds ..
T. pannonicum Jacq
T. pmtiflorum Ehrh
T. pratense * L
T. procumbent L
T. rcflexum L
T. repens > L
T. resupinatum L
T. rubens L _
T. scabrum L
T. spadiceum L
T. squarrosum L
T. subterraneum L. _ _
T. thalu Vill— _
T.tumens Stev
T. mriegatum Nutt
T. wormskjoldii Lchnt-
14
*9
8
'48-49
Kar-
pet-
scben-
ko 2n
« 130
lfi
14
14
Wex-
elsen
In
16
32
10
32
16
3 48
i Reports on additional chromosome counts: T. repens, 2ffl=16, A. O. Erith. T, repens, m=about 12,
J. N. Martin. T. medium, 2n=78, J. N. Armstrong, Centra] Experimental Farm, Ottawa, Canada, by
correspondence. T. pratense, n=7, J. Kawakomi. T. repens, n=lt>, J. Kawakomi.
' About. 3 Specific identity uncertain. * Uncertain, not enough material.
Table 2. — Location, kind of clover, and past and present personnel engaged
in clover improvement
[An asterisk (*) designates workers whose salaries are completely or partly paid from Federal funds]
AMEKICAN WORKERS
Location of workers
Kind of clover
Past personnel
Present personnel
Washington, D. C
All clovers
Eed, sweet, white...
A. J. Pieters,* H. S.
Coe,*L.W.Kephart.«
H. W. Hulbert
E. A. Hollowell.*
C. A. Miehels.
Urbana, 111 _
W. B. Gernert
C. M. Woodworth, D.
Eed
Ileusinkveld,* J. J.
Pieper.
G. II. Cutler, H. E.
F. S. Wilkins,* S. N.
Smith.
Mulvey.
H. D. Hughes.
J. W. Zahnley.
do
lied _-
E. N. Fergus, W. D.
St. Paul, Minn
L. E. Kirk, F. R. Irn-
mer, H. E. Brew-
baker, C. W. Dox-
tater.
Valleau.
H. K. Hayes, H. K.
Wilson, I. J. Johnson,
W. M. Meyers.
T. A. Kisselbach, S.
G a r v e r,* K. F.
Manke.*
H. B. Sprague, E. M.
Hodges.
J. B. Park.
H. A. Schoth.*
Bed
Knoxville, Tenn
do
S. M. Bain, S. H.
Essary.
C. S. Sherbakofl.
P. B. Dunkle.
do_ _
do
V. B. Hawk
C. R. Burnham.
White, red, and
sweet.
E. A. Brink, W. K.
Smith,* O. F. Smith,*
O. S. Aamodt, H. S.
Ahlgren, J. G. Dick-
son, F. Tinney.*
1214
YEARBOOK, 1937
Table 2. — Location, kind of clover, and past and present personnel engaged in clover
improvement — Continued
PARTIAL LfST OF FOREIGN WORKERS (COMPILED FROM REPORTS RECEIVED)
Location of workers
Kind of clover
Past personnel
Present personnel
Australia:
New South Wales
Red, white, sub-
terranean.
S. L. Macindoe, W. T.
Tasmania, Strathroy
Atkinson.
R. II. Bevin, E. F
Victoria-
Subterranean, white-
Subterranean
Fricke.
West Australia, Muresk
Drake, E. D. Cameron.
T. C. Dunne.
Agricultural College.
Canada:
Ontario:
Ontario Agricultural
Red, white
0. M. McConkev
College.
Guelph _
Dominion Experi-
mental Farm,
Ottawa.
Saskatchewan, University
Red _
M. 0. Malte, (}. P.
McRostie, R. I. Ham-
ilton.
S. Bracken, L. E. Kirk . _
L. S. Klinck, L. A.
Waitzcngen, C. P.
McRostie, A. Mac-
Taggart.
L. E. Kirk, J. M. Arm-
strong.
of Saskatchewan, Saska-
toon,
Quebec, MacDonald Col-
Red
White.
J. N Bird
lege.
Wales:
Welsh Plant Breeding
Red, white, crimson-
Red, alsike, white,
sweet.
Red
R. D. Williams
Station, Aberystwyth.
Germany:
Kaiser Wilhelm Institute,
W. Rudorf, F. Hack-
harth Schrock.
Berlin.
Netherlands:
Agricultural High School,
Wageningeu.
Norway:
Felleskj0pets Stamsaedga-
do
ard, Hjellum.
Apelsvoll, Toten
White
Vagtines, Bod0.
Red
Union of Soviet Socialist Re-
publics:
Institute of Plant Indus-
do
Lissitzyn, Sinskaya.
N. Sylen, O. Nilsson-
Leissner, R. Torssell,
R. Nilsson, J. E.
Siden, O. Eriksson,
E. Akerberg.
try, Leningrad.
Sweden:
Sveriges Utsiidesforening
Svalof.
Switzerland:
Swiss Agricultural Ex-
Red, white, alsike
Red.— -_
II. Witte, a. Eriksson,
B. Kajanus.
periment Station,
Orlikon.
VARIETAL IMPROVEMENT
IN HOPS
D. C. SMITH, Formerly Agent,
Division of Drug and Related
Plants, Bureau of Plant Industry '
XjUPULIN, a substance consisting of resins and essential oil,
imparts to beer, ale, and other malt beverages their characteristic
bitter flavor. The scales or bracts of the hop — which resembles a
fir cone in its general makeup— possess small, yellow, granular bodies
or lupulin grains, easily visible to the eye (fig. 1). These contain the
resins and oil. The oil, contributing also to the aroma, is usually
driven off in the boiling process but may be replaced later. Materials
known as tannins occurring in the scales and stem of the cone aid in
the clarification of the brew after boiling.
Each 31 -gallon barrel of beer brewed in the United States requires
only a half to four-fifths of a pound of hops, though abroad the figure
sometimes reaches 1% pounds. Thus in spite of the extent of the
brewing industry, the acreage of hops required is of minor importance
agriculturally when compared with many crops. Hops are all-
important to the brewers, however, since beer is made principally of
malted barley, hops, and water. There are rather exacting require-
ments in quality of hops, and both yield and quality are determined
by many influences. Breeding of better hops, therefore, becomes an
undertaking of vital concern both to brewers and to growers.
In other countries attention has been given to hop breeding as
a means of improvement for many years. Such work with hops
in the United States is at its beginning, though much progress has
been made in recent years in breeding other crop plants. Some of
the back-ground of hop culture will help the reader to better under-
stand the breeder's work.
USE OF HOPS ANCIENT IN ORIGIN
Just when hopped beer was first made is not known. The Egyptians
had a sweet-sour alcoholic beverage made like beer but without
hops. Hops were apparently used by the Greeks only as a salad
plant; even today young hop shoots are eaten like asparagus by some
people. In early times hops were supposed to free the blood of
"all impurities, tumors, and flatulence", cure the itch and other skin
diseases, and "relieve the liver and spleen." Taken as a fresh vege-
table, they may well have had some beneficial effect in the diet.
Today individuals may be found who believe that sleeping on a
pillow stuffed with dried hops somehow contributes to health.
i Previously in charge of hop-breeding investigations. The author is indebted to Q. B. Hocrner, agent,
Division of Drug and Eclated Plants, for collaborating on some parts of this paper dealing with pathology,
and to Frank Babak, associate biochemist in the same Division, for making the chemical and physical
examinations and furnishing the data in tables 1 and 0.
1215
1216
YEARBOOK, 1937
But the overwhelming utilization of hops has been in brewing, this
use being first developed either in Kussia or in Germany. German
records go back to 768 A. D., in the time of Charlemagne, when King
Pepin le Bref donated hop gardens to the monastery of St. Denis.
Subsequently many monasteries became famous for their brews. By
1320-30 A. D., hopped beer was in general favor in Germany. Hop
culture spread to the Netherlands, and John the Bold, Duke of
Burgundy, founded a
Knightly Order of the
Hop. Late in the fif-
V BL teenth century the plant
was introduced into Eng-
land, but Henry VII and
Henry VIII liked beer
without hops and prohi-
bited their use. Swedish
tastes were the opposite;
an ordinance of 1440 re-
quired every farmer to
grow 40 poles of hops. In
Bohemia the Emperor
Charles IV personally se-
lected the spots most suit-
able for hop growing.
Today leading producing
countries abroad are Eng-
land and Wales, Germany,
Czechoslovakia, France,
and Belgium.
In North America, hop
growing began in New
Netherlands as early as
1629 and in Virginia in
1648, though it did not
become important until
about 1800. In 1808 the
first hop yard was estab-
lished in New York. In
1849 the New England States and New York produced nearly
1,500,000 pounds, of which New York grew 70 percent. After the
Civil War the industry developed in Wisconsin, reaching a maximum
of 25,000 bales2 in 1869. In 1865, Oneida County, N. Y., produced
1,265,000 pounds, and in 1879 the State reached ah all-time maximum
of 21,629,000 pounds.3
The growing of hops on the Pacific coast was started between 1859
and 1869. Though New York was still the leading State in 1899,
the production in Oregon and that in California each exceeded that of
New York by 1909. In recent years hop cultivation in this country,
except in Washington, Oregon, and California, has been negligible.
Figure 1. — Branch of hop vine with mature, well-
developed cone helow and blighted, withered cones
due to downy mildew above and to the side.
' Present commercial bales weigh approximately 200 pounds.
' Attention of the reader is called to the appendix at the end of this article, listing sources of information
available.
HOPS 1217
In 1935 these three States harvested 47,746,000 pounds of hops on
38,900 acres. Slightly over half of the tonnage was grown in Oregon.
During the twenties hop growing in New York was practically
wiped out by powdery mildew, but there is a revival of interest in
that State, as indicated by the work recently begun by the New York
(State) Agricultural Experiment Station at Geneva looking toward
the improvement of hop varieties.
The growing of hops is somewhat similar to that of pole beans.
The vines are trained on poles or pole-and-wire trellises, ordinarily
10 to 20 feet in height. Plants are spaced from 4 to 8 feet apart, the
latter distance being most general on the Pacific coast. At harvest
the vines are let down and the cones are picked by hand. The green
hops arethen hauled to drying houses, piled in bulk, and slowly dried
with artificial heat for about 20 hours. Later they are compressed
into bales of about 200 pounds each, sewn over with burlap, and the
grower's part is completed.
Hops are long-lived perennial plants propagated by root cuttings
and having a strong climbing habit. Curiously enough, the vines
always wind in the same direction. New shoots are produced each
year, and after harvest old growth is removed as in the case of cane
fruits. Plants may be grown from seed, but they then exhibit great
diversity in characters, many being strikingly inferior. Few growers
have noticed hop seeds germinate. Hop plants possess remarkable
vigor, young vines having been observed, under favorable conditions,
to elongate 12 inches in 24 hours.
Hops are closely allied only to elm, mulberry, hemp, and nettles
among the commonly known plants and are known to botanists as
Humulus Iwpulus L. A native American type has been segregated as
H. americanus Nutt. An annual ornamental variety called the
Japanese hop (FI. japonicus Sieb. and Zucc.) is a cousin, as is
H. neomexicanus (A. Nels. and Cockerell) Eydb., a native sort found in
BEER, ale, and other malt beverages depend principally on hops
for their characteristic flavors, and no satisfactory substitute has
ever been found. Improvement of hops by breeding is, therefore,
of vital concern to both brewers and growers. The attainment of a
choice product is very difficult, since the hop plant is extremely
sensitive to sun, wind, heat, rain, insects, and diseases, and the
quality of the cone depends on type, color, soundness, aroma, and
content of resins and essential oils. Breeding may play an im-
portant part in improving most of these characteristics. The
varietal improvement program is new in the United States and
though the hop plant is not easy to deal with, the progress made in
developing superior varieties in Europe suggests what may be
accomplished with sustained and active investigations.
1218 YEARBOOK, 1937
Colorado and vicinity. The first two species mentioned include all
commercial hop varieties.
PECULIARITIES AND PROBLEMS IN HOP BREEDING
The hop is one of the few cultivated plant species in which male and
female flowers are borne on different individuals. Since commercial
bops are the dried and pressed cones from the female plants and
these develop without fertilization, the males are not indispensable
in commercial culture. The latter do serve to stimulate production
of larger, heavier, and earlier maturing cones by the female plants
{20).* Such hops contain seeds, which contribute to the weight but
which have no value in brewing, and in parts of continental Europe
the presence of male plants in yards is forbidden by law. In the
United States and England about 1 male to 100 female plants may
be grown.
To the breeder, seed production is necessary, since it is in seedling
progenies that opportunity for selection of improAred varieties is most
promising. The breeding problem is closely analogous to that in
dairy-cattle improvement. There is no method of determining the
value of a sire in providing desirable heredity to obtain high-producing
cows except by progeny tests, since milk production, like hop develop-
ment, is a purely female character. Nevertheless, from a hereditary
viewpoint, the male contributes markedly in each case.
Brewing Requirements, Yield, and Maturity
The characteristics of choice hops, from the brewmasters' view-
point, are relatively few. They should possess a high soft-resin
content, delicate aroma, and a clean, bright appearance, and contain
few or no seeds, leaves, and stems. Because of the slow, gradual
development and fragile nature of the cone, coupled with the extreme
sensitivity of the plant to sun, wind, heat, rain, insects, and diseases,
the attainment of a choice product is exceedingly difficult. Harvest-
ing operations also play no small part in determining the quality of
hops received by the brewery. Though much investigational work
has been done in attempts to find suitable substitutes for hops, the
use of this crop continues to be the only means in use of giving the
desired qualities to beer.
In the culture of hops, the grower has many serious troubles.
Most important among these are maintenance of yields, control of
diseases and insects, standardization of high quality, and many
minor difficulties arising from these. The first task of the breeder is
to recognize and understand these factors.
The world over, yields of dry hops per acre may range from 300 to
4,000 pounds. While much depends on the country and locality, the
variety used is of chief interest in this respect. The principal vari-
eties of the Pacific coast are Late Clusters, comprising about 75
percent6 of the acreage ; Fuggles, about 15 percent; and Early Clusters,
10 percent. In good years, Late Clusters produce an average of about
1,500 pounds, Early Clusters 1,300 pounds, and Fuggles 1,100 pounds
of dry hops per acre. Incidentally, yields in continental Europe are
« Italic number in parentheses refer to Literature Cited, p. 1239.
! Includes some Canadian Red vines.
HOPS 1219
usually from 600 to 1,100 pounds per acre while those of England and
Wales approximate those of the United States.
Fuggles is the earliest maturing variety, usually being ready for
harvest about August 20, with Early Clusters closely following.
Ripening of Late Clusters, which is the main crop, begins in Oregon
in early September. Maturity of hops is generally earlier in Cali-
fornia and to some extent in the Yakima Valley of Washington.
Harvesting of Late Clusters may extend into early October. Many
growers have acreages of two or more varieties, which allows a longer
harvesting season. Increased yields are always a breeder's objective
and the period of maturity is of importance in most sections.
Downy Mildew, Scourge of the Hop Plant
Like other plants, hops are attacked by various diseases, the most
serious of which, at the present time, is downy mildew. Other
important troubles in the United States are blue mold or powdery
mildew, sooty mold, which accompanies infestations of plant lice,
and crown gall. Blue mold, a serious disease in England and to some
extent responsible for the decline of hop production in New York,
has not been reported on the Pacific coast. Sooty mold may be
serious in any year when plant lice are prevalent. These diseases
may attack hop cones, leaves, roots, or stems causing lowered quality
or complete destruction. The effects of downy mildew on cone
development are shown in figure 1. In addition to those mentioned,
other minor diseases of various types have often been present in
Europe and the United States.
In recent years hop growers throughout the principal hop-growing
countries have been greatly concerned with downy mildew. Its
ravages have resembled in many respects those of the late blight
disease of the potato, which caused the Irish famine in 1845 and 1846,
or of the frequent stem rust epidemics of cereals in the Middle West.
Downy mddew was first described in Japan in 1905. In 1909 it
was observed in the United States, being found in Wisconsin. In
1920 minor attacks of the disease were seen at Wye, in Kent, England,
but in 1921 it was not observed there. During 1922 and 1923 it in-
creased in prevalence at Wye, and in 1923 it was reported in Germany
and Czechoslovakia. Belgium and France reported it in 1924 and
the Union of Soviet Socialist Republics in 1925. In 1926 it appeared
in Italy. Beginning in 1927 serious losses were caused, England suffer-
ing damage estimated at nearly one-third of the crop and Bavaria
also experiencing heavy losses. Some Bavarian growers sprayed 10
times during the season to control the spread of the trouble. Since
1927 the disease has appeared irregularly in Europe, but in indi-
vidual localities losses may involve the entire crop. Weather condi-
tions are important influences in the development of the disease.
Though found in Wisconsin in 1915, downy mildew did not cause
economic losses in North America until 1928, when it appeared in
New York, Manitoba, and British Columbia. In 1929 it developed
extensively in western Washington and in 1930 was severe in western
Oregon. The disease did not appear in coastal California until 1934
and in the Sacramento Valley until 1935. During 1936 it was
prevalent in all areas where it had been found previously and caused
1220 YEARBOOK, 1937
a marked reduction in the yield and quality of the crow. To date it
has not been officially recorded as existing in the Yakima Valley of
Washington, though experienced growers have reported traces of it.
While downy mildew appears irregularly, it has been estimated
that 20 to 25 percent of the crop is annually lost through the depre-
dations of this disease in the Pacific Coast States. The source of
the organism causing downy mildew (Pseudopernospora humuli
(Miyabe and Tak.) Wilson) is problematical, but it is thought
to be native on wild hops in the United States. The control of
this devastating disease is perhaps the most important concern of
hop producers both in the United States and in Europe and is a
major objective of the breeder.
Quality and Other Considerations
Particularly in recent years, but more or less persistently over a
long period, growers have been concerned with problems affecting
quality. Considered from the variety-improvement viewpoint, items
of importance are soft-resin content, aroma, and the existence of
seeds. Commercially, hops are bought on the basis of general variety
or type, color, aroma, lupulin content, and soundness. These might
be termed "sight", "smell", and "touch" characters, and experienced
growers and dealers rely greatly on these three senses. Recently
resin content as determined by chemical analysis has become a
greater influence in the hop trade.
Proper attention to the various steps in harvesting and curing
favors quality to a large extent, but aside from this, variety and
locality are also extremely significant factors. With respect to
soft-resin content, American-grown hops are equal or superior to the
best European lots. The latter are reputed to be preferable in aroma.
Continental hops are also noteworthy for their freedom from seeds
as compared with the English and American products. German and
Bohemian hops continue to sell at a high premium over domestic lots
in the New York markets. Though sufficient domestic production
of hops for supplying the American trade usually exists, the use of a
certain percentage of foreign hops for brewing is a general practice
in this country. To improve the quality of domestic hops is thus
another primary object of breeding efforts.
Insects affecting hops most frequently are plant lice or aphids and
the red spider. These pests exist in both European and Pacific coast
hop sections. Root borers, cutworms, flea beetles, and other insects
occasionally do considerable damage. Aphids have been generally
present and, where they are numerous, the secretion of honeydew, a
sticky sweet substance, reduces quality and serves as a substratum
for molds to develop. Red spiders affect the foliage mainly and are
usually prevalent under conditions of slow growth and dry, warm
weather.
In picking, hops that separate readily from the vines are har-
vested with the least crumbling and breaking. Types that tend to
remain without disintegration in the complete processes of ripen-
ing, harvesting, and drying result in the best dried samples. Plants
must be long-lived to keep down yard maintenance costs and main-
tain high yields.
HOPS 1221
EARLY DEVELOPMENT OF VARIETIES
The natural variability of the hop plant and the futility of attempt-
ing to propagate commercially by means of seed was recognized at an
early date (13). In 1669, different types were distinguished, and by
1726 the existence of male and female plants was noted by European
growers. Many varieties were known by 1799. The desirability
of growing uniform sorts was also acknowledged though in England
during the nineteenth century there was a great confusion of varieties.
During the development of the industry in the United States, as
in Europe, many named varieties have been grown that, with the
exception of the four now grown on the Pacific coast, have disappeared
from commercial fields. Introductions of foreign types made from
time to time by producers of extensive acreages have also vanished
for the most part.
In the important years of production in New York several varieties
grown included English Cluster, Grape, Canada Red, Palmer Seedling,
and Humphrey Seedling. The latter types were also cultivated in
California and in addition the so-called "American hop" was grown.
The Fuggles variety did not prove popular in California.
The earliest recognition by the Department of Agriculture of the
need of improved vaiieties of hops in the United States was in 1900,
when David Fairchild imported roots of the best European varieties.
After thorough tests it was found that these did not yield well enough
to make their production under American conditions profitable.
In 1904 he started breeding work and crossed European varieties with
American male plants. Prior to this American hop growers had from
time to time sought to accomplish the same purpose in the same way
with similar results.
In 1908 Stockberger (17) outlined a program he had undertaken
in the Department of Agriculture. He referred to the failure of the
earlier attempts to adapt European varieties and suggested a different
procedure based on a recognition of the fact that the hop plant is
greatly influenced by soil and climatic conditions, so that improve-
ment by selection of the best varieties already being grown in this
country would be simpler and give quicker results. He proposed a
careful study of the domestic varieties, the selection of promising
individual seedlings, and thereafter the development of desirable
types by hybridization. Although the chief objectives he sought
related to productiveness and quality, he stated that individual hop
plants had shown a marked resistance to disease and that these were
being propagated to determine not only whether that character is trans-
mittable but to note their general qualities from other standpoints.
Progress on this project was reported in brief statements in the
Yearbooks of the Department of Agriculture for 1911 and 1912 in
which the selection of several promising hybrid seedlings and the con-
tinued introduction of foreign sorts is referred to. By 1916 several
thousand seedlings were under cultivation. About this time a number
of circumstances forced the abandonment of the project. A reduction
in funds made a continuation of the field work impossible. The
European war interfered with further importations of foreign varieties,
and a few years thereafter the advent of prohibition greatly reduced
the commercial importance of hops.
1222 YEARBOOK, 1937
The investigations of State experiment stations have not until
recently been directed toward problems concerning; hop varietal im-
provement, and early Federal experiments have not been continuous.
Principally because of the inroads of downy mildew, experimental
work with hops was initiated in 1930 by the Division of Drug and
Related Plants of the Bureau of Plant Industry, United States De-
partment of Agriculture, in cooperation with the Oregon Agricultural
Experiment Station. The principal purpose of the program was to
investigate disease control through field practices and to work toward
the development of improved, disease-resistant varieties. Experi-
ments have been in progress since that time. More recently varietal
improvement of hops has been started by the New York (State)
Agricultural Experiment Station at Geneva, as previously mentioned.
In Europe there seems to have been from early times a careful
selection of stocks, varieties appearing and disappearing frequently.
Though the origins of many strains are obscure, numerous ones are
known to have resulted from selection of chance seedlings and others
by propagation from desirable plants. The Late Clusters variety is
thought to have arisen from a chance seedling of the wild hop. The
origin of Fuggles is typical of the development of many strains.
Concerning it Percival (6, p. 87) wrote:
The original plant was a casual seedling which appeared in the flower-garden
of Mr. George Stace, of Horsmonden, Kent. The seed from which the plant
arose was shaken out along with crumbs from the hop-picking dinner basket used
by Mrs. Stace, the seedling being noticed about the year 1861. The sets were
afterwards introduced to the public by Mr. Richard Fuggle of Brenchley, about
the year 1875.
Another old English variety, Colgate, was started from a likely
looking plant found growing in a hedge. Bates Brewer was developed
from root cuttings obtained from an outstanding plant that was paid
for in whisky (6). Many of the continental varieties undoubtedly
began with similar plant selections. The varietal history of hops
closely resembles that of potatoes. Selections of seedlings by growers,
followed by vegetative propagation, have frequently originated new
types in both plants.
Fruwirth (4, PP- 77-88) assigned the origin of several early varieties,
including Golding, Early Brambling, and Semsch, to bud variations,
the variants then being propagated independently by cuttings. This
is comparable to the bud or graft propagation of new apple types
appearing on trees of old varieties.
Individual workers, not growers primarily, undertook independent
investigations late in the last century. Fruwirth began selection of
promising individuals in 1888. Other workers mentioned by Fru-
wirth were Stambach, who first planted seedlings in 1894, and Remy,
who in 1898 was making studies of the resins and tannins of seedlings.
Early work also included that of Beckenhaupt at Weissenburg and
Wagner at Weihstephan, Germany, who grew local and introduced
varieties in comparative trials.
Organized efforts for hop improvement began fairly late in the last
century. A testing garden was established near Saaz, Bohemia, in
1897, and many varieties were grown. Breeding by seedling selection
had begun in Belgium by 1903. About 1898 the Agricultural College
HOPS 1223
of Wales began investigations on hop improvement, and breeding was
undertaken in 1907. One of the oldest and most active investiga-
tional projects has been in progress in England since about 1904. In
1913 visitors to the college hop nursery at Wye, Kent, selected prom-
ising seedlings for trial and subsequently 2,830 cuttings from 23
varieties were supplied to growers. A testing station especially for
determining brewing value was established at East Mailing in 1917
and has made important contributions to the English work. By
1911 Denmark had begun variety investigations. Additional stimu-
lation was given to hop breeding in Europe generally by the severe
losses due to downy mildew in 1926 and 1927. In 1926 a society for
hop research was founded in the Hallertau district of Bavaria. In
1932 a large German hop company placed its acreage at the disposal
of the government for testing purposes. The work of hop selection
in the Union of Soviet Socialist Republics, undertaken by the Agri-
cultural Academy of Moscow, began in 1926. In addition to those
mentioned, other state, governmental, and private agencies in Europe
are concerned with varietal improvement of hops. In the appendix
are listed some of the workers and the countries in which experimental
work is in progress.
RECENT BREEDING WORK
The improvement of hop varieties concerns the cone-bearing female
individuals particularly. When seeded hops are grown, male plants
that produce abundant pollen at the time of the flowering of the female
plants are needed. Thus selection of desirable male plants may be
necessary.
Considering grower and trade demands, an ideal variety would
embody resistance to downy mildew, high yield, suitable resin content,
and good aroma. It would be medium leafy, easily picked, resistant
to insects, and capable of remaining on the vines a reasonable time
after maturity without deterioration. Excessive fragility and large
stems would be undesirable. This indicates the varied character
of the hop-breeding problem. Meanwhile, new diseases or other
troubles may appear to provide additional complications. Considering
all these points, no varieties commonly grown at present quite "fill
the bill."
Recent work has developed along several important lines. In 1930
and 1931 an extensive survey was made of the plant material being
grown in commercial yards of Oregon, to determine the possibility of
selection of superior types in old hop yards. In 1935 a similar, though
less comprehensive, inventory was made in coastal California. Super-
ficial examinations have also been made of a few Yakima Valley yards
in Washington. The general result of these surveys has been failure to
find occasional plants, which might be propagated as improved types,
strikingly superior to the general lots of the four important varieties.
There has frequently, however, been a varying percentage of inferior
sorts, the elimination of which would allow a sizeable increase in
production. Such types have been chiefly hermaphrodites 6 and
sterile plants producing no flowers, often called bastard hops by
'Hermaphrodites, as in animals, are individual plants developing both male and female sexual characters.
In hops such plants produce pollen and also cones.
1221
YEARBOOK, 1937
growers. In many yards male plants are unnecessarily numerous for
pollination purposes. Additional work is being done on vegetative
selection among commercial varieties and the breeder is constantly
watching for superior individuals.
In all plant improvement one of the most promising methods of
obtaining better types is the introduction of varieties from foreign
Figure 2. — Vines of the Late Clusters variety of hops, with side branches covered with
glassine bags to control pollination. Bags are held in place by paper clips, and
operations are recorded on small marking tags attached to the stems.
countries having growing conditions comparable to those in our own
hop areas. Experience has not been promising as to the value of this
practice in hop improvement, but it is hoped that useful breeding
material will be acquired by this means. Beginning in 1931, attempts
have been made to obtain propagation stock of superior English and
continental varieties to grow in the experimental nursery at Corvallis,
Oreg., in comparison with domestic sorts. Though some European
countries have prohibitions against the exportation of cuttings, in all
about 35 foreign strains have been obtained by the Division of Plant
Exploration and Introduction and are now being grown. Cuttings
for propagation improperly packed are perishable and in some instances
difficulty has been experienced" in obtaining living roots shipped long
distances. Plants from imported cuttings do not usually bear hops
until the second year.
The third method of attack that may be used for variety improve-
ment is the selection of superior plants from those grown from seed.
This plan appears to offer most promise. Since it is difficult to desig-
nate male individuals according to variety, all seeds produced may be
considered of hybrid nature. Thus seed may be collected from any
good female in the hope that some of the progeny will excel the
HOPS
122c
mother plant in various characters. The nature of the male parent
in such a case is unknown. It is also possible to obtain seeds from
plants that have been pollinated artificially. In these cases the nature
of the male is known, and vigorous, desirable types may be used. When
controlled pollination is practiced, the female flowers are covered with
Figure 3. — View of experimental yard showing plant variation among hop seedlings.
Those in the foreground are superior types.
small bags and pollen of the male plant is shaken over the blossoms. A
plant undergoing artificial pollination is illustrated in figure 2.
Hop Yards for Experimental Testing
The experimental field at Corvallis, Oreg., consists of an area trellised
and spaced like a commercial yard and another smaller section for
growing seedlings for the first year's observations. The larger area,
pictured in figure 3, is capable of accommodating about 3,500 plants
spaced 8 feet apart. Included in this section are plantings of all
domestic and available foreign varieties, together with seedling plants
that appear worthy of growing beyond the first year. The smaller area,
known as the seedling yard, is designed for growing first-year seedling
plants for preliminary observation. Seedlings are planted 15 to 18
inches apart in the row and trained on strings attached to a wire
approximately 6 feet from the ground level. About 3,000 plants may
be grown under these conditions (fig. 4). Seedlings that appear to be
of the types sought are then transplanted to the standard yard for
further tests. Hop seeds may be sown in greenhouses or in coldframes
in the field in early winter or early spring. In the growing season the
138004° — 37 78
1226
YEARBOOK, 1937
Figure 4. — First-year hop se
tiling;? in nursery yar
variable growth.
INole closcn
planting and
Figure 5. — Seedling hops in greenhouse beds. The dome lamps may be used to supple-
ment daylight during fall and winter months. Strong seedlings are thus developed for
field planting in the early spring.
HOPS
1227
plants obtained are moved into the seedling yard or into field rows to
be later included in the nursery. Seedlings growing in greenhouse beds
are shown in figure 5.
Though, in general, growing conditions are kept favorable for plant
growth in the experimental areas by following common commercial
methods, the nature of the information sought requires certain widely
divergent practices. One of
these is the actual fostering
of the development of the
downy mildew disease by
cultural practices favorable
to its spread so that it will
"run wild" among both the
older plants and the seedlings
under observation. Since
resistance to this malady is
one of the chief goals, its
rapid spread is sought, to
permit selection of resistant
types. Where it may seem
apparent that plants vary in
reactions to insects, the lat-
ter pests may also be left
uncontrolled. Since it is
not desirable to select plants
under soil conditions ex-
ceptionally favorable for
growth, the use of fertilizers
is restricted. Otherwise,
plants are allowed to de-
velop in a manner compa-
rable to those in commercial
yards.
During the growing sea-
son many types of observa-
tions are made. The de-
velopment of downy mildew
and the plant's reaction to
it are recorded weekly for some 3,000 seedlings and foreign and do-
mestic varieties. Data are also taken on infestations of aphids and
red spider. Relative maturity, vigor, stem and leaf color, leanness,
abnormalities, and sex are also recorded in seasonal notes previous
to harvest.
Late Clusters, Early Clusters, and Fuggles are grown in plots of
sufficient size and number of plants to obtain information on yields.
In 1934 and 1935 over 400 such plants were picked and weighed indi-
vidually. Other less common varieties, such as Red Vine and
Bavarian, are also grown though less extensively. Foreign strains
and all promising seedlings are harvested individually but have not
been grown on a comparative yield basis, for reasons indicated later.
After picking, samples are dried in a small experimental drier (fig. 6)
through cooperation with the Oregon station section of agricultural
Figure 6. — Experimental hop-drying chamber.
The small cabinet within contains the samples of
hops, placed in coarse mesh bags. The scale
beam allows constant checking of moisture losses
as the charge is dried. Drying temperature and
heated-air flow may also be recorded.
1228 YEARBOOK, 1937
engineering. The hops are then pressed into small bales resembling
the commercial package except in size.
Chemical tests have been made on many samples to determine the
soft-resin content as a means of obtaining some index of quality.
Physical examinations have also been made for color, aroma, seed
content, cone size and condition, and presence and appearance of
lupulin. At present, the chemical and physical analysis of the dry
hops, is the ultimate test for brewing value. Actual brewing tests
will be necessary to finally establish the suitability of new strains for
commercial use.
Breeding Objectives and Progress
In the hop-breeding project thus far, definite information has been
obtained on a number of problems, and observations made since 1930,
together with contacts with growers and dealers, have served to
crystallize objectives.
Late Clusters, the dominant domestic sort, is normally a good
yielder, has a high soft-resin content, and is other-wise well suited to
brewing purposes. It is, however, quite susceptible to downy mildew,
plant lice, and red spider. It is also leafy and late in maturity.
Early Clusters is very susceptible to downy mildew and aside from
being somewhat earlier is interchangeable commercially with Late
Clusters. The cones are larger and the vines a little less leafy. It is
a favorite with pickers. Fuggles is resistant though not immune to
downy mildew, usually making a fair crop when cluster varieties are
severely injured. Yields are decidedly lower than those of the
Early Clusters and Late Clusters and the variety does not permit as
much delay in harvest as does Late Clusters. It is also quite sus-
ceptible to red spider injury. The soft-resin content of Fuggles is
usually below that of the cluster types and the commercial trade
recognizes the variety as an individual class.
Red Vine hops have been grown more extensively in earlier years
than at present; very few uniform fields of this variety now exist;
It is noted for its pleasing aroma and many growers believe a small
amount of Red Vine hops adds in this respect to the quality of Late
Clusters. The soft-resin content is comparable with that of Late
Clusters. Chief objections to Red Vine are leafiness, many small
hops — though the yield is good — late maturity, and susceptibility to
aphis, which is due in part to profuse foliage.
Where suitable males are present, all of these varieties produce
abundant seed, but the prevention of seeding might easily be accom-
plished by elimination of male plants. Inability to obtain satisfactory
premiums for seedless hops has not encouraged growers on the Pacific
coast to eliminate seeds.
None of 30 varietal strains introduced from other hop-growing
countries has appeared to be superior or equal to those now grown
on the Pacific coast. This may be comparable with the results of
extensive corn trials in the United States where many varieties do
well only within small areas or localities. Certain of the introduced
varieties have made fair growth and several have exceeded Late
Clusters in percentage of soft resins. In table 1 are given results of
physical and chemical analyses of some foreign and domestic hops
Table 1. — Physical and chemical analyses of hop varieties and seedlings grown at Corvallis, Oreg., 7935
Variety or seedling
Color
Aroma
Lupulin
Cones
Total
soft resin
Foreign varieties:
Yellow, very plentiful. _ _.
_ do __
Percent i
20 88
Small
do
19.92
19.17
do ._
18.60
Small to medium _
17.87
M 45
do
17.70
Pale green.-
do _
..do.
17.54
do _
..do.
17.54
Domestic varieties:
do..
Mild, agreeable
Lemon, yellow, very plentiful ...
Small to medium.
Medium to large .
Medium _
19.12
Early Clusters. _.
do
Lemon yellow, plentiful
17. 62
Strong, not pleasant,
17.11
Seedlings:
52-31
Pale green. _.
Lemon yellow, plentiful ..
19.71
S-12 - - -
do .
19.06
62-27
Small to medium. .
Medium to large
Small to medium _ _
.. do, .
18.12
101-32
Very mild, pleasant-. _- . .
Very plentiful ...
Plentiful
17 75
36-32
17.70
73-12
17.20
70-13
Pale green
Yellow, plentiful
Medium . . .....
17.16
1 Based on air-dry hops.
! Of uncertain origin, possibly a domestic selection by growers.
(S3
1230
YEARBOOK, 1937
grown at Corvallis, Oreg., in 1935. Though the data are for 1 year
only, the analyses are remarkably high.
The soft-resin content is based on individual determination of
several resin components, which is the usual method of chemical
analysis. The notes on physical characteristics of the various lots
are of importance, since commercial dealers usually observe these
points in trade samples. Comparisons may be made between foreign
and domestic varieties
by reference to the
table. Though all of
the samples listed
might be considered
choice from a trade
viewpoint, superiority
of certain strains is
indicated. In both
1934 and 1935 Land-
hopfen and Burgunder
exceeded Late Clus-
ters, the richest domes-
tic variety, in per-
centage of soft resins.
Analyses of certain of
the better seedling
selections indicate
the possibilities for
obtaining improved
types in this important
character.
Wide variations in
physical traits may be
noted, though soft-
resin contents remain
similar. Aroma partic-
ularly may vary from
excellent to strong and
unpleasant when other
characters seem to
vary but little.
Many seedlings have
been grown at Corval-
lis since 1931. Seed
has been obtained from
domestic and foreign varieties from the experimental yard and from
many commercial fields. These seedlings have been for the most
part of inferior types. Many are male plants, others are dwarfed
or otherwise undesirable, and only rarely is a plant producing "fair"
hops obtained. One of the latter sorts, considerably better than
usual, is illustrated in figure 7.
In the matter of soft-resin content, seedlings may vaiy over a wider
range than varieties. In the 1933 season 29 of these varied from 9 to
Figure 7. — A promising seedling hop plant having a cone
type resembling Fuggles and leaves similar to those of
Late Clusters.
HOPS 1231
17.9 percent,7 while Late Clusters contained 17.9, and Fuggles 16.3
percent soft resins. In the crop of 1934 cones from 57 seedlings con-
tained between 9.4 and 17.8 percent of soft resins. The percentage for
Late Clusters was 17.8 and for Fuggles 14.8. Nineteen foreign varie-
ties grown at Corvallis under similar conditions ranged from 14.2 to
19.4 percent soft resins. Similarly, the 1935 crop of 50 seedlings
ranged from 11.1 to 19.7 percent; Late Clusters contained 19.1 and
Fuggles 17.6 percent. Foreign varieties, 23 in number, varied from
14.1 to 20.9 in percentage of soft resins.
In aroma, many seedlings have compared to advantage with standard
varieties while some are decidedly inferior.
Experience has demonstrated, both here and abroad, that plant
reaction to downy mildew is difficult to ascertain. This is due to the
irregularity of the occurrence and development of the disease. The
nature of this problem may be indicated by the fact that one seedling
of a very promising nature in the years 1931-33, free from mildew and
of good agronomic appearance, mildewed severely in 1934 and 1935.
Preliminary tests have shown that artificial inoculation of questionable
plants by hypodermic injection of the mildew organism may be
feasible. This would tend to supplement the work of nature in the
development of the disease and make possible more rapid progress.
Results at Corvallis offer some assurance of obtaining seedlings
resistant to the downy mildew disease.
Since yields of foreign types have been obviously inferior to those of
commercial varieties, comparative yield tests of the former with
domestic sorts have not been made. Neither have any of the foreign
varieties proved to be highly resistant to downy mildew.
Results thus far indicate that leaf, stem, cone form, and . cone
arrangement are fairly constant from year to year. Plants producing
male or female or both types of flowers in any one year tend to be
similar in other years though occasionally marked exceptions may occur.
Resistance to aphids and red spider has not been found in any
varieties or seedlings observed. Though many plants have not been
injured, several years' observation, as in the case of reaction to downy
mildew, will be required to definitely determine the stability of this
character.
In summary, of the improvements sought, agronomic characters,
including high yield and desirable cone type, have proved to be the
most difficult of attainment, judging from recent experience in the
breeding project. Between 15,000 and 20,000 seedlings, of which
approximately 3,000 have been grown to the cone-producing stage,
have allowed selection of fewer than 10 with records of resistance to
mildew, high resin content, and good agronomic qualities. Most of
these may not survive continued tests.
It is proverbial among plant workers that varietal improvement
usually requires consistent work over many years before great practical
benefits can be shown. While propagation by cuttings simplifies the
plant breeder's job in that plants "impure" from the hereditary stand-
point may be reproduced as uniform, true-breeding commercial
varieties, in the case of hops this advantage is counterbalanced by
problems not usually met in such work.
' Based on moisture-tree sample.
1232 YEARBOOK, 1937
Large Numbers of Plants Needed for Effective Selection
Caring for large numbers of plants individually during a period of
several years requires a large area and much labor. Picking and
drying many samples separately and the making of chemical tests also
present physical problems. All of these limitations mean that the
work is necessarily slow.
Growers of the Pacific coast have shown new concern in im-
provement problems since 1931. Of interest in this regard also
is the initiation of the varietal improvement project by the
New York (State) Agricultural Experiment Station, previously men-
tioned.
Though European varieties have not to date proved to be adapted
to conditions on the Pacific coast, the progress made in developing
improved types in Europe by seedling selection offers hope for com-
parable progress in the United States.
Mildew Records
An obstacle common to all breeding for resistance to disease is the
frequent necessity of waiting for natural development of epidemics
before plant reaction can be obtained. Downy mildew appears
capriciously, and 8 to 10 seasons may be required to adequately deter-
mine plant reaction to this disease. Yield and quality are variable
characters requiring tests of several seasons' crops.
Methods of recording and comparing data on downy mildew reaction
from season to season have presented a troublesome problem. At
present such notes are taken at approximate weekly intervals while
the epidemic is spreading, and plants are classified by numbers
from 0 to 5 as representing progressively increasing numbers of
leaves or branches infected by the disease. Comparative classi-
fications of 2,827 plants upon which notes were taken in 1934
and 1935 are given in table 2. The differences of reaction from
year to year due to variation in the development of the epidemic
through the area are indicated. In 1934, for example, 294 plants
were classified as no. 5 in reaction, or very susceptible. Of these,
183 failed to develop symptoms in 1935. Of the 1,788 plants
classed as 0 in 1934, 1,543 did not mildew in 1935. The data show
that even with downy mildew generally present, many susceptible
plants may escape infection.
Table 2. — Downy mildew, incidence in experimental yard, Corvallis, Oreg., 1934-35
1935 classification '
Plants
n each classification
in 1034
Total
0
1
2
3
4
5
0
1, .543
41
105
2
1
30
1,788
90
2
8
0
0
3
304
7
02
2
2
25
58
3
22
4
1
15
62
0
20
2
0
8
183
10
60
2
1
38
2,249
I . . _ _
09
2
307
3
12
4.
6
.5
125
Total
112
432
103
08
294
2,827
' 0 to 5 represents progressively increasing numbers of infected leaves or branches.
HOPS
1233
Seasonal Productivity
Various agronomic reasons for unproductive hills were suggested by
Bressman (1), and Stockberger (19) indicated certain conditions influ-
encing yields. Attempts have been made to determine the consistency
of yield of hop plants (18) from year to year. Growers often experi-
ence unexplainable irregularity of development and production in yards
usually uniform. The question has arisen also as to the possibility of
continuously selecting from the most vigorous plants as a means of
increasing yield by isolation of more vigorous types. Information
is being sought that will answer these questions more completely.
In 1934 and 1,935 hill surveys were made of 25 different marked
areas of 100 hills each in some 15 yards, on several soil types in
western Oregon. Plants were classed as S (strong), M (medium),
W (weak), X (untrained — also a weak type) and 0 (indicating no
plant present), at two periods in each season. A contingency table
(table 3) shows the relations between 1934 and 1935 notes taken just
previous to harvest. Hills designated as O in 1934 were replanted in
the early spring of 1935. The data indicate unexpected irregidarity
in the seasonal growth and productivity of any particular class of
plants. Frequently individuals classified as strong in one season
may be considered as weak or even fail to produce hops the succeeding
year. Contimiation of records may provide information serving to
throw light on such variations.
Table 3. — Summary comparing hill survey of plant types, commercial yards,
Willamette Valley, Orcg., 1934-35
1935 classification '
Plants in each classification in 1934
Total
S
M
51
W
X
0
S . _
390
216
98
91
9
27
4ft
21
9
33
6
5
7t
95
60
227
29
51
773
M
105 4
336
W
X
85
10
45
I
0
0
437
51
0 _
128
Total.
695
50
462
1,728
i S=strong; M=mcdium; \V=weak; X=untrained; 0=no plant present.
Production data add more precisely to the interpretation of this
problem. Actual yields on individual plants from the experimental
yard in 1934 and 1935 are available on the Late Clusters, Early
Clusters, and Fuggles varieties. Correlations between yields of the
two seasons are indicated in table 4.
Table 4. — Yield data/or three varieties of hops, 1934-35
Variety
Plants
Mean yield
r value
P value
exceeds—
1934
1935
Number
101
113
125
7.9±0.50
7. 19±. 40
5. 60±. 20
12. 14±0. 49
7.94±.31
7.2«±.19
0.19
.57
.39
0.05
.01
.01
1234
YEARBOOK, 1937
In general a significant relation between yields from year to year
is exhibited, although the correlation coefficient for Late Clusters is
° ' Other Important Technical Studies
Analyses of the results of artificial pollination have been complicated
by two major problems — (1) the slow and irregular germination of hop
seeds, and (2) the doubtful results of bagging. Somewhat detailed
studies have shown greatly increased and more rapid germination as a
result of cold treatments. One of the best of the treatments used was
placing the seeds in moist blotters in a germinator for 5 days at room
temperature followed by refrigeration for 5 weeks at 5° C. Such pro-
cedure has increased germination from less than 10 to over 70 percent.
Once seeds have germinated and plants have emerged, growth may be
rapid. Artificial illumination has been reported by Brcssman (2) as
of value in stimulating vegetative development.
Results of bagging and subsequent pollinations have been incon-
clusive. Some seeds have developed within and outside of glassine
and parchment bags whether or not enclosed flowers were artificially
pollinated. The bags used have been tightly secured to the branches
by paper clips. Flowers have been covered at various early stages of
development, from the period immediately preceding the appearance
of the stigmas through the time when they withered. Whether plants
form seed parthenogenically, without fertilization, or whether seed
obtained from bagged, unpollinated flowers will grow has not been
satisfactorily determined. Thus far the possibility of incomplete ex-
clusion of pollen from bagged flowers does not seem adequate to explain
the results obtained. Winge {20), Howard (5), and others, however,
have reported the failure of seeds to set when pollen was not allowed to
reach bagged flowers. Relations between ability of male pollen from
different plants to cause fertilization and ability of females to produce
seed are also being determined. Until seed formation and germination
can be more accurately controlled, the results and the value of hybridi-
zation will be uncertain.
Constancy in development among various plant characters from
year to year is indicated in table 5. Fundamental information is
needed in this respect to form a basis for plant selection.
Table 5. — Constancy of plant vegetative characters
Plants in each classification in 1934
1935 classification
Dwarfs
Dwarfed
Witches'-
tiroom
Bagged
Russeied
Colored
vines
Total
2
13
0
19
4
6
0
6
0
17
3
14
0
1
17
3
0
0
0
1
0
65
5
4
0
2
0
18
29
4
1
1
0
CO
14
265
3
24
Witches'-hroom
17
188
55
293
Total
-14
40
21
75
53
■ 347
680
Descriptive differentiation of the classifications seems unnecessary
to illustrate the variations in vigor and type of growth from season to
season. With the exception of colored vines, other classes are plant
HOPS
1235
weaknesses and therefore undesirable. Occasionally vigorous plants
of good general type may show light russeting of leaves. Ragged
plants develop torn or ragged leaves and flowering branches may be
partially or entirely sterile. The type known as "witches'-broom"
is apparently the sterile dwarf described by Salmon (7). It is possible
that some of the conditions listed may be pathological while others
may be due in part to genetic factors. While detailed notes are
available for 2 years only, a marked constancy of growth character is
evident in certain groups.
In dioecious species such as hops the expression of sex is of particular
interest. Development of hop plants as to sex appears to be generally
constant though infrequent, wide deviations apparently occur. It
is a fairly common observation of growers that in some years more
male plants appear than usual.
In approximately 1,200 seedling plants in the experimental yard
upon which notes have been taken for sex, the following deviations
occurred in 2 years, 1934 and 1935:
Plants
Change from male to female 5
Change from male to hermaphrodite 8 2
Change from female to male 1
Change from female to hermaphrodite 1
Change from hermaphrodite to male 2
Change from hermaphrodite to female 5
« See footnote 7, p. 1230.
Deviations may be noted in all degrees of sexual expression. Data
are insufficient to justify generalizations as to which transformations
occur most frequently or to suggest possible explanations. Observa-
tions of Chartschenko (3) in this respect are noted later. Salmon (7)
has recorded relative frequencies of male and female individuals in
seedling progenies, as well as other developmental types.
The variation to be expected in resin analysis of hops from the
same plants from year to year is a factor requiring careful study.
Even though individuals are harvested at as nearly the optimum
time as possible and all other factors are controlled similarly, large
differences may exist from season to season. This is illustrated in
table 6, comparing examples taken at random from yearly analyses
of individual plants.
Table 6. — Soft-resin contents of hops from individual seedling plants
Seedling no.
Soft-resin content for— •
Seedling no.
Soft -resin content for— '
1933
1934
1935
1933
1934
1935
36-7
Percent
18.22
17.10
17.49
Percent
17.95
16.96
16.77
Percent
16.03
15.93
14.30
62-27—
Percent
17.53
18.70
14.60
Percent
14.93
17.61
10.24
Percent
18.12
53-10
8-10 _
16.77
19-33
56-28
12.88
1 Percentages on dry basis.
The data show the relative inaccuracy of analysis of a single year's
crop as a strict indication of plant behavior, at least for some individ-
uals. Plants might, however, be placed in general groups as good,
fair, and poor, with reasonable accuracy in most instances. Increased
1236 YEARBOOK, 1937
experience and additional care in harvesting, drying, and packaging
of samples will undoubtedly decrease the errors encountered.
Contributions by Various Investigators
A brief review of investigated points of interest in hop breeding will
indicate the nature of some of the problems and the facts obtained in
other hop-growing countries. Though hops were investigated at an
early date, comparatively little information on breeding aspects may
be found in the literature. Reference has already been made to
certain work. An attempt to bring together scattered supplementary
facts and further outline the general background seems desirable.
It was early noted that plants from seeds were variable and most
often poor (18). A wide range of maturity was also noted in such
progenies '(15). In addition it was recognized that new varieties
might arise either from seeds or from bud variations.
Salmon (7) obtained the following results from seed progenies
derived from controlled pollinations:
From 256 seeds 87 seedlings were produced, of which 52 plants were normal
and 35 were sterile dwarfs.
From 285 seeds 67 seedlings included 66 fertile and 1 dwarf plant.
From 261 seeds 120plants, all of normal vegetative growth, included 108females,
111 males, and 1 hermaphrodite.
From 899 seeds 109 seedlings included 79 normal plants and 30 sterile dwarfs.
The dwarf plants made little growth compared to normal plants
and failed to form flowers of any kind. Such results represent the
expected appearance of many inferior plants in seed progenies, how-
ever derived. Studies of three groups of seedlings reported by
Fruwirth (4) indicated the proportions of female plants to be 66, 77.7,
and 90 percent respectively, in the progenies considered.
Pollinated cones were found by Winge (20) to be larger and heavier
than those whose flowers were not pollinated. Unpollinated hops
were observed to remain longer in the bur, and stigmas at the stem
end were noted to appear first (5). Fertilized cones were also thought
to mature earlier and resist mold to a greater degree than those
unfertilized.
In order that pollination might be complete, it was recognized that
male plants must shed pollen throughout the bur period of the females.
Pollen from hermaphroditic plants was determined to be viable and
to be capable of fertilization (20). Chartschenko (3) reported female
flowers of such plants to produce viable seed.
The impossibility of crossing two female plants has been pointed
out, though combinations of female varietal characters in one individual
may often be desirable. In addition it seems obvious that since male
plants do not bear hops, their value in use as parents must be deter-
mined with appreciable difficulty.
As early as 1894 Stambach, cited by Fruwirth (4), planted out
seedling hops for observation. Remy, mentioned by the same writer,
studied resins and tannins of seedling hops hi 1898. He crossed
cultivated female varieties with wild males, crossed an F1; or first
generation, male of the progeny with a cultivated female plant, and
then recrossed an F! male of the latter progeny back to a cultivated
female. This is a comparatively complicated crossing scheme but is
occasionally used by plant breeders.
HOPS 1237
Reversals in the nature of the sexual character of hop plants have
been reported by several workers, according to Fruwirth (4). Chart-
schenko (3) has given examples of sexual changes. A male plant
was described as changing to a normal female in 2 years, being a
hermaphrodite in the third, and a normal male again in the fourth
year. In another case a cutting from a female plant produced a vine
bearing male flowers. In yet another instance two female plants
changed to hermaphrodites. Vegetative increase of these also gave
rise to hermaphrodites.
Much interest has been shown in studying relations of numerous
plant characters to the important property of resin content and other
indications of quality. Fruwirth (4) reported high yield to be asso-
ciated with inferior aroma, greater foliage production, stouter strigs
(center stem of cone), and plant longevity. Chodounski, mentioned
by Fruwirth, thought coarser hops to be characterized by inferior
hairing, lack of uniformity in strength, abnormal structure, and
other characters of the strig. Sutora, cited by the same writer,
concluded that a coarser strig and darker green color of the hop is
associated with a lower tannin content. According to Fruwirth,
finer hops were thought by Wagner to have smaller bracts and a
smaller bract area. Percival (6) pointed out that delicacy and weak-
ness of cones were often met with in hops of the best quality. Salmon
has indicated that a theoretically choice English hop might combine
high soft-resin content with the aroma of present English or Saaz
varieties (8). He stated that total resin contents remain fairly con-
stant from season to season in varieties generally (9). Chartschenko
(3) reported that Russian work had failed to establish any female
characters as being associated with resin content. Within varieties
no significant relation was found between resin content and yield of
green hops or earliness of ripening, or in most cases between earliness
and yield of green hops. Appreciable variation was found as to resin
contents between vegetative selections within varieties. Results of
analyses of male plants in which resin contents varied from 1.77 to
3.48 percent were given. Attention was directed to the importance
of this in view of the fact that the male contributes half the inheritance
of the progeny in this and other characters.
It has been accepted that variety has more to do with resin and oil
content of hops than soil or locality. Other factors that influence
these characters are climate, fertilizers, maturity, drying methods, and
seed content. The aroma of certain types of American hops has been
compared with the odor of turpentine, black currant leaves, onions,
rue, and apples, and therefore said to be inferior to that of European
hops (8). Resin content (14) and aroma (16) have been found to be
inherited traits and progeny plants may exceed the female parent in,
these important attributes.
In one instance of a cross, the aroma of an Oregon female plant was
exhibited by about three-fourths of its progeny. Aroma has been
shown to be transmitted through the male, by the same investigator
(16). . .
Characters recognized as constituting differences among varieties
have included vine color and length of internodes; maturity, arrange-
ment, and form of strobiles; color, number, and form of leaves; leafi-
1238 YEARBOOK, 1937
ness in proportion to cones and stems; and relative dry weights of the
cones. Though variation seemed less marked in males, they were
found to be generally as variable as female plants {22).
American varieties introduced into England have proved to be
unsuited there and it has been concluded (8) that introduction of
foreign varieties has little value except for use as parents in obtaining
superior seedlings. This may represent the major value of varietal
introductions made into the United States.
Since the appearance of downy mildew in European hop culture,
attention has been directed to varietal response to this and other
diseases. Salmon (9) has reported many of these results, which
eventually have served to classify all varieties as mildew-susceptible
though in varying degrees. Saaz hops, at first thought to be immune,
mildewed in 1932. Fuggles is one of the most resistant types, but
both leaf and. cone infection have occurred. Some strains may be
resistant to cone infection. Many of the most resistant sorts are now
in commercial use. Salmon (10) has also observed certain varieties
and seedlings to be resistant to blue mold.
In England the "mosaic disease", so called because of its mottled
coloring effects on the leaves, affects all hops except the varieties
Fuggles, Tolhurst, and Colgate. Nettlehead and chlorotic diseases
have been found only on Fuggles (8). In 1926 mosaic disease was
serious in Yugoslavia. Mosaic disease, nettlehead, and the chlorotic
diseases are virus 9 troubles not generally reported from hop-growing
countries.
Crossing experiments with hops have been carried out in most
European countries since 1900. Hybrids between Humulus neo-
mexicanus and II. lupulus have been reported (11). Imperfectly
formed seeds of II. lupulus and II. japonicus have been obtained (20),
but these have failed to produce plants.
Cytologic investigation has received little attention to the present
time, though Winge (20, 21) has studied the genus Humulus in some
detail. Chromosome numbers in H. lupulus have been found to be
20 in the vegetative cells (diploid). These have been designated as
18+2X in the female and 18+X+Y in the male. In II. japonicus
17 have been assigned to the male (14+3X) and 16 to the female
(14+2X) (21).
Absence of more complete information on inheritance of plant
characters is undoubtedly due to the sexual nature of the hop species
and attendant problems in obtaining satisfactory progeny tests.
As previously mentioned, the situation approaches that in higher
animals.
Breeding Program Slow But Promising
• Isolation of improved varieties of hops resistant to downy mildew
and otherwise superior to present domestic sorts appears to be reason-
ably practical. Present objectives in hop breeding are well recognized
and methods of reaching desirable ends are in the process of estab-
lishment. Kesults obtained in England indicate promise for consistent
investigation. Hop breeding experiments initiated at Wye, Kent, in
1907 have resulted in significant improvements of the English crop.
Salmon (12) has recently announced the development of two valuable
9 An infectious principle not recognized as due to a particular organism, but capable of causing disease.
HOPS 1239
new varieties, Brewer's Favourite and Brewer's Gold. The first of
these is a seedling originating in 1909 from a plant of Oregon Cluster
(probably Late Clusters) introduced into England, and it has been
tested extensively since that time. Brewer's Gold is also a seedling,
first raised in 1919. These varieties are high yielders, producing cones
rich in soft resins and otherwise acceptable to both brewer and grower.
Based upon breeding investigations with crops of other kinds as
well as hops, continued experimentation will be necessary if progress
is made such as has been reported in other countries. The breeding
project requires observation of numerous plants in comparative field
and chemical tests over a long period.
(1) Bressman, e. N. LITERATURE CITED
1931. UNPRODUCTIVE HOP PLANTS AND VARIETIES IN OREGON. Joiir. Inst.
Brewing 37 (n. s. 28): 372-377, illus.
(2)
1931. developing new varieties of hops. Science (n. s.) 74: 202-203.
(3) Chartschenko, N.
1934. ZUR FRAGE DER METHODIK DER HOPFENZUCHTUNG. Zlictlter 6:
113-119, illus.
(4) Fbuwibth, C.
1924. HANDBUCH DER LANDWIRTSCHAFTLIOHEN PFLANZENZUCHTUNG. Aufl.
4 . . ., v. 3, illus. Berlin.
(5) Howard, A.
1905. THE INFLUENCE OF POLLINATION ON THE DEVELOPMENT OF THE
hop. Jour. Agr. Sci. [England] 1: [49J-58, illus.
(6) Percival, S.
1901. the hop and its enolish varieties. Jour. Rov. Agr. Soc. Eng-
land 62: 67-95, illus.
(7) Salmon, E. S.
1914. ON THE APPEARANCE OF STERILE "DWARFS" IN HUMULUS LUPULUS L.
Jour. Genetics 3: 195-200, illus.
(8)
(9)
1917. the value of hop-breeding experiments. Jour. Inst. Brewing
23 (n. s. 14): 60-97.
(10)
(11)
(12)
1918-35. [reports of the trials of new varieties of hops.] See
Southeast Agr. Col., Wye; East Mailing Research Sta., Kent; and
Jour. Inst. Brewing for various years.
1921. ON forms of the hop (HUMULUS LUPULUS L.) resistant to mildew
(SPHAEROTHECA HUMULI (DC.) BURR.) J V. Ann. Appl. Biol.,
8: 146-163.
1930. hop-breFjDing experiments, 1917-30. Jour. Inst. Brewing, 36
(ii. s. 27): 578-591, illus.
1934. two new hops: "brewer's favourite" and "brewer's GOLD."
Jour. Southeast Agr. Col., Wye, Kent 34: 93-106, illus.
(13) and Wormald, H.
1921. A STUDY OF THE VARIATION IN SEEDLINGS OF THE WILD HOP (HUMU-
LUS lupulus l.). Jour. Genetics, 11: 241-267, illus.
(14) Schmidt, J.
1915. JOHS. SCHMIDT: INVESTIGATIONS ON HOPS (HUMULUS LUPULUS,
L.). VI. ON THE AMOUNT OF LUPULIN IN PLANTS RAISED BY
crossinc. Compt. Rend. Lab. Carlsbcrg 11: [165]-183.
(15)
1915. JOHS. SCHMIDT: INVESTIGATIONS ON HOPS (HUMULUS LUPULUS, L.).
VIII. ON THE FLOWERING TIME OF PLANTS RAISED BY CROSS-
ING. Compt. Rend. Lab. Carlsberg 11: [188]-198.
1240 YEARBOOK, 1937
(16) Schmidt, J.
1917. JOHS. SCHMIDT: INVESTIGATIONS ON HOPS (HUMULUS LUPULUS, L.).
X. ON THE AROMA IN PLANTS RAISED BY CROSSING. CoHipt.
Rend. Lab. Carlsberg 11: [330J-332.
(17) Stockberger, W. W.
1908. IMPROVEMENT OF HOPS BY SELECTION AND BREEDING. Amcr.
Breeders' Assoc. Proc. 4: 156-161.
(18)
1912. a study of individual performance in hops. Amer. Breeders
Assoc. Ann. Rept. 7-8: 452-457.
(19) ■ and Thompson, J.
J 910. some conditions influencing the yield of hops. U. S. Dept.
Agr., Bur. Plant Indus. Circ. 56, 12 pp., illus.
(20) WlNGB, O.
1914. johs. Schmidt: investigations on hops (humulus lupulus, l.).
in. the pollination and fertilization processes in humulus
lupulus l. and h. japonicus sieb. et zucc. Compt. Rend. Lab.
Carlsberg 11: 1-44, illus.
(21)
1929. ox the nature of the sex chromosomes in humulus. Hereditas
12: [53]-63, illus.
(22) Wormald, II.
1915. variation in the male hop, humulus lupulus, l. Jour. Agr.
Sci. [England] 7: [175]-196, illus.
GENERAL REFERENCES TO LITERATURE ON HOP
PRODUCTION, CULTURE, AND IMPROVEMENT
Braungart, R.
1901. DER HOPFEN ALLER HOPFENBAUENDEN LANDER DER ERDE ALS BRAU-
material. 898 pp., illus. Miinchen and Leipzig.
Flint, D.
1900. hop culture in California. U. S. Dept. Agr. Farmers' Bull. 115,
28 pp., illus.
Hoerner, G. R.
1932. downy mildew of hops. Oreg. State Agr. Col. Ext. Bull. 440, 11 pp.,
illus.
Meeker, E.
1883. hop culture in the united states; being a practical treatise
on hop growing in washington territory from the cutting
to the bale. 169 pp., illus. Puyallup, Wash.
Myrick, H.
1899. THE HOP; ITS CULTURE AND CURE, MARKETING AND MANUFACTURE . . .
299 pp., illus. New York, Springfield, Mass. [etc.].
Parker, H. H.
1934. the hop industry. 327 pp., illus. London.
Salmon, E. S., and Ware, W. M.
1931. the hop downy mildew and its control. Pub. Univ. London,
Dept. Econ. Mycology, Southeast Agr. Col., Wye, Kent.
Stockberger, W. W.
1922. growing and curing hops. U. S. Dept. Agr. Farmers' Bull. 304,
36 pp., illus.
Sulerud. G. L.
1931. an economic study of the hop industry in Oregon. Oreg. Agr.
Expt. Sta. Bull. 288, 77 pp., illus.
APPENDIX
Workers and Stations Concerned with Varietal Improvement in
Hops and Hop Breeding u
R. E. Alexander, Canterbury Agricultural College, Lincoln, New Zealand.
A. Arkhaugelsky, Plant Breeding Experimental Station, Moscow Agricultural
Academy, Moscow, Union of Soviet Socialist Republics.
" No implication is made that this list is complete, since it is based in the main on correspondence with
foreign workers.
HOPS 1241
Ctibor Blattny, Institute of Phytopathology, Prague-Dejvicc, Sadova, Czechoslo-
vakia.
K. N. Curtis, Cawthron Institute, Nelson, New Zealand.
Mario Curzi, Crittogamica di Pavia, Pavia, Italy.
V. Ducomet, Botany and Plant Pathology, Department National School of Agri-
culture, Grignan, France.
R. E. Fore, Division of Drug and Related Plants, United States Department of
Agriculture and Oregon Experiment Station, Corvallis, Oreg.
Edmond Gain, University of Nancy, Nancy, France.
R. Hampp, Freising, Baycrn, Germany.
J. D. Harlan, New York (State) Agricultural Experiment Station, Geneva, N. Y.
Instituut voor plantenveredeling, Wageningen, Netherlands.
R. Kirchner, Hop Experimental Institute, Vienna, Austria.
V. E. Kovalevich, Union of Soviet Socialist Republics Scientific Researching
Station of Hop Growing, Shitomir, Union of Soviet Socialist Republics.
S. O. Kulczynski, Botanical Garden, Lwow, Poland.
W. Lang, Landes Anstalt fur Pflanzenschutz, Hohcnheim, Germany.
E. I. McClennan, Botany Department, University of Melbourne, Victoria,
Australia.
R. Muck, Saaz, Czechoslovakia.
Petricek Cooperative Hop Society, Zalec, Yugoslavia.
E. S. Salmon, South Eastern Agricultural College, Wye, Kent, England.
U. Simoens, Service des Agronomes de l'Etat, Ypres, Belgium.
F. Zattler, Bavarian National Institute for the Cultivation and Protection of
Plants, Munich, Bavaria, Germany.
138904°— 37 79 + +
IMPROVEMENT OF
FOREST TREES
ERNST J. SCHREINER, Forest
Geneticist, Northeastern Forest
Experiment Station, Forest Service
JT ORESTRY is a young profession. In comparison to agriculture,
it has just been born. Under pressure of necessity, farmers wore
breeding crop plants long before genetics supplied the key to many of
the mysteries they encountered; but the natural products of the forest
were plentiful and were taken as needed, without thought of artificial
replacement. Until very recently, indeed, even foresters have been
Figure I. — A "man-made forest" of slash pine in southeastern Louisiana. The
artificial regeneration of cut-over lands on such a large scale emphasizes the need
for guidance from sound genetics work in the improvement of forest trees.
content to utilize wild trees as they were found. This lack of interest
in the improvement of forest trees has been due both to the lower unit
value of the stock and to the greater difficulties involved in breeding
work.
Various factors have been responsible for a gradual change in atti-
tude within recent years. The rapid recession of the timber supply
accessible to established wood-using industries; the inferior quality
1242
FOREST TREES 1243
of much of the second-growth wood; more stringent quality require-
ments in the finished product to meet the competition of other manu-
facturers or of substitute products, necessitating uniformity or im-
provement in quality of the raw wood material; the denudation of
forest areas by uncontrolled commercial exploitation and the necessity
for having them restocked and managed by public agencies in the
public interest (fig. 1); the urgency of soil conservation on nonagri-
cultural lands — all these have played a part in exerting pressure for a
more intelligent attitude toward the forest problem as a whole, and
the exploration of any possibilities that might be promising.
The tree breeder, then, has just begun to roll up his sleeves. In
comparison with his confreres who deal with the older agricultural
crops, his attitude is one of humility ; he is only at the beginning and
he has much to learn. But on the other hand, because his work is all
before him, he sees infinite possibilities ahead for the improvement
of forest trees by breeding and selection,
This should be kept in mind by the reader as he peruses the follow-
ing brief account of the present status of breeding work with forest
trees. In various parts of the world, considerable necessary spade-
work has been and is being done. Much of it might not be called
either genetics or breeding by those who have become facile in dealing
with the smaller, quicker maturing crop plants. Nevertheless, this
spadework will be of great value to forest-tree improvement, and it is
essential to the building up of a science of forest genetics. The ap-
pendix gives a concise summary of most of the work relating to forest-
UNTIL very recently, foresters have been content to utilize wild
trees as they were found. There has been a gradual change in view-
point, brought about by the same factors that have exerted pressure
for a more intelligent attitude on the part of the public toward the
forest problem as a whole — the depletion of the timber supply ac-
cessible to established wood-working industries; the inferior quality
of much of the second-growth wood; more stringent quality require-
ments in the finished product; the denudation of forest areas by un-
controlled commercial exploitation; the urgency of soil conservation
on nonagricultural land. Today foresters are eager to explore any
possibilities that might be promising, and tree breeding seems to be
one of the most promising. In comparison with the breeder of the
older agricultural crops, the tree breeder has just begun; his attitude
is one of humility; but because his work is all before him, he sees
infinite possibilities ahead. In various parts of the ivorld much
necessary spadework is now being done to lay the foundations of a
true science of forest genetics.
1244 YEARBOOK, 1937
tree breeding now being carried on by public and private agencies in
the United States, and some of the work being done in foreign coun-
tries.
The improvement of any wild stock should logically begin with (1)
a segregation of varieties, races, and strains of the wild population.
It should then proceed to (2) the evaluation of the characteristics of
each group, (3) the selection of the best individuals in each of the best
strains, (4) breeding and selection, which controls both parents and
utilizes the best germ plasm available in these wild stocks, and, finally,
(5) the production of decidedly new types by hybridization and by
advantageous use of induced or natural changes in the normal number
of chromosomes (polyploidy). The improvement of forest trees
strictly along these lines would require extensive investigation and
planting over many years. Fortunately, all five phases can well be
carried on simultaneously.
STUDIES OF SEED ORIGIN— SPECIES, VARIETIES,
RACES, STRAINS
For more than 00 years investigators have recognized the importance
of seed origin, for which the term "provenience," meaning origin, is
often used. The importance of races and strains of forest species
first became apparent in Europe, where artificial regeneration of
forest stands has been in progress for a much longer period than in
the United States. European foresters began to realize that constant
and important variations appeared between progenies from seed
obtained in different regions. For example, in Sweden, Scotch pine
grown from European seed often produced trees of very inferior forest
form. Careful study indicated that proper selection of the seed
source was necessary for the production of a desirable type of growth
and an economically profitable stand. These investigations have
led to fairly well controlled seed certification in some parts of Europe.
Forest research stations in the United States (fig. 2) have also been
interested in this problem of seed origin (fig. 3) and experimental
plantations were started over 20 years ago at several western stations.
Test plots established at the Pacific Northwest Forest Experiment
Station in 1915, with seed of Douglas fir, have already given valuable
data on the existence and characteristics of various strains within
this species. Seven apparently superior strains of ponderosa pine
have been segregated at the Northern Rock}7 Mountain Forest
Experiment Station from test plots established 23 to 27 years ago.
Work at these and other stations is described in the appendix.
The establishment of the Eddy Tree Breeding Station (now the
Institute of Forest Genetics, California Forest and Range Experi-
ment Station)1 in 1925 initiated a project for the intensive study of
various problems in forest genetics. Extensive tests at the institute
include 100 species and named varieties of pine (the genus Pinus) and
innumerable climatic forms of many of these species. The seed has
'The Eddy Tree Breeding Station was originally founded and financed by James G. Eddy at Placerville,
Calif. In 1931, the station was incorporated and deeded to a board of trustees, the name bein^ changed to
the Institute of Forest Genetics. Between the years 1931 and 1935 the institute received aid from the Car-
negie Institution and the U. B. Department of Agriculture (Bureau of Plant Industry, Soil Conservation
Service, and Forest Service). On July 1, 1935, Congress granted funds to carry on work in forest genetics
at the California Station and in this year the property of the institute was deeded to the Federal Govern-
ment and became part of the California Forest and Range Experiment Station.
Figure 2. — Regions covered by the forest experiment stations of ihc Forest Service and the principal timber types of the regions
to
1246
YEARBOOK, 1937
been obtained from approximately 40 countries. In addition to tbe
work with Pinus, 35 species of conifers, representing 17 genera, and
20 species of hardwood trees, representing 13 genera, have been in-
cluded in this project, which at the present time is apparently the
most comprehensive program of this nature in the United States.
Valuable data have already been collected from these plantations,
Figure 3. — Tbe importance of seed origin is shown by these 5-year-old Scotch pines.
The tree on the left, of central European origin, has inherited rapid growth but a very
poor and ultimately unprofitable growth habit. That on the right, from seed collected
in Norway, has grown more slowly but will develop into a good forest tree.
and the institute will undoubtedly evaluate superior germ plasm for
the breeding and selection of superior forest stocks.
Briefly stated, the investigations in connection with the problem
of seed origin have shown that in many, if not all, important forest
species there are rather distinct races and strains that differ in their
hereditary response to a given complex of environmental conditions.
Such races and strains probably have been evolved in response to
the environment peculiar to their original habitat. Although the
best reforestation results in any particular region can usually be
expected from seed collected locally, or from a region in which the
seed trees have been subjected to apparently similar environmental
conditions, there are enough exceptions to this generalization to indi-
cate that a great deal more investigation is required before the in-
herent adaptability of races and strains can be accurately cataloged.
INDIVIDUAL SEED-TREE PROGENY TESTS
Individual seed-tree progeny tests resulted from the realization that
seed origin was of tremendous importance to the forester in considering
FOREST TREES
1247
artificial reforestation. Observations that the individuals of the same
seed origin showed marked differences in growth habit,in ra te of growth,
and in resistance to disease, climate, and site conditions, stimulated a
further refinement in seed-selection studies. Investigations were soon
started on the inherent characteristics of the progeny of individual
Figure 4. — Individuals of ponderosa pine growing in the same stands show inherent
differences in vigor of growth. These two 7-year-old trees are from wind-pollinated
seed collected from different seed trees in the same field plot in Eldorado County,
Calif. The sister seedlings of both these trees were uniformly more vigorous than those
of the slower growing pine of figure 5.
trees. Recognition of only the female parent was involved, since most
of the important forest trees are wind-pollinated, and the source of
the pollen that had fertilized the seed was necessarily unknown. _
A number of European institutions are now engaged in individual
seed-tree progeny tests. Oppermann, in Denmark, was among the
first to insist on the necessity of carefully selected seed trees. Nicolai
of Danzig, in particular, has stressed the importance of this problem
and has started work with several forest species.
In the United States, many of the forest experiment stations have
included individual seed-tree progeny tests in their research program.
The Rocky Mountain Station has located individual trees of the
Eonderosa pine which are apparently mistletoe-resistant and has
egun individual progeny tests with seed from these trees. Mistletoe
infection often seriously retards the growth rate in this region and on
the poorer sites often results in high mortality. Individual seed-tree
progeny tests with green ash at the Lake States Station indicate that
there are inherently different climatic races within this species.
1218
YEARBOOK, 1937
An extensive progeny test was started in 1929 at the Institute
of Forest Genetics with 742 individual seed trees of Pimis ponderosa
(ponderosa pine) and its varieties scopulorum and jeffreyi (Jeffrey pine)
Results to date indicate that there are apparently innumerable local
strains, each with distinct mor-
* phological and physiological char-
acteristics, and that individual
trees vary strikingly in their abil-
ity to produce superior seedlings
(fig. 4) . This test included seed
trees from 60 counties in 12 West-
ern States and British Columbia
(fig. 5). A more intensive prog-
eny study, restricted to Eldorao
County, Calif., where types with
the greatest hereditary vigor
seemed to occur, was started with
the 1934 seed crop. The insti-
tute is also testing the individual
seed progenies of 16 species and
natural hybrids of walnut.
The results obtained from indi-
vidual seed-tree progeny tests
indicate that individual trees,
growing under the same environ-
mental conditions, vary greatly
in their ability to produce good
offspring and that it is therefore
necessary to establish criteria for
the recognition of heritable quali-
ties. Adequate information for
the description of good seed trees
is not available at present.2
HYBRIDIZATION OF FOREST TREES
Numerous natural hybrids have been observed from time to time and
the parentage of some of these has probably been accurately ascer-
tained. Among such natural hybrids the following may be noted:
Larix eurolepis * (Dunkeld larch) from L. europaeaXL. leptolepis
L. gmeliniXL. Kaempferi.
Pinus sondereggii from P. palustris (longleaf pine) X P. laeda (loblollv pine)
P. halepensisXP. pinaster.
P. nigraXP. sylvestris.
P. montanaXP. sylvestris.
P. montanaXP. nigra.
Picea sitchensisXP. canadensis.
P. engelmanniiX P. canadensis.
Salixcoerula (cricketbat willow) from S. albaXS. gracilis.
Ulmus glabraX U. ?nontana (Huntingdon elm).
Quercus cerrisXQ. siiber (Lueombe oak).
Royal walnut hybrids (eastern black walnut X various California black walnuts)
Poplar hybrids (Eugenei poplar, Serotina poplar, and others).
Figure 5. — This tree is typical of the com-
paratively slow growth of the British Co-
lumbia strain of ponderosa pine. Compare
it with the more vigorous trees of the same
age shown in figure 4. Racial differences
are clearlv indicated.
' Additional information on individual seed-tree progeny tests is included in the appendix
Species names have too often been applied to hybrids between tree species; in the case of poplar
clones existing as a single sex. Hybrids are not species and naming them as such can onlv U "
. to hybrid
lead to confusion.
FOREST TREES 1249
Many of these hybrids grow more vigorously than either of their
parents, and in some instances other valuable properties or char-
acteristics have been noted. For example, the Dunkeld larch is
said to be resistant to the larch canker, and the wood of the cricketbat
willow is said to be particularly well adapted to the manufacture of
cricket bats. _ _„
Early Work
If possible, tree breeding should begin with stock that has been
selected on the basis of its breeding quality (superior germ plasm),
but since 1845 investigators have been interested in the possibilities
of hybrids between species of forest trees, primarily because of the
fact that species hybrids often surpass their parents in vigor of growth
(so-called hybrid vigor). _ Klotzsch * is generally considered to have
produced the first artificial hybrids between forest-tree species. In
1845 he hybridized two species each of pine, oak, elm, and alder, and
observed that the resulting hybrids possessed growth characteristics
superior to their respective parents.
Sporadic attempts to hybridize forest-tree species continued over
many years. Ness, working at the Texas Agricultural College,
produced a few hybrids between the live oak and the overcup oak in
1909, and a limited amount of breeding appears to have been con-
tinued atthis station. Henry, working in England, produced several
fast-growing poplar hybrids and in 1916 published a paper on the
possibilities of obtainmg rapid-growing forest stock by hybridiza-
tion. Since 1916, there have been a number of publications discussing
various aspects of the possibilities of hybridizing trees. The loss of
our native chestnut through the introduction of the Asiatic chestnut
blight stimulated interest in breeding this group, and as a result
W. Van Fleet, of the United States Department of Agriculture,
carried on breeding work with American and Asiatic chestnut species
in an effort to produce an immune or resistant timber type.
Recent Work
_ The chestnut-breeding work started by Van Fleet has been con-
tinued and expanded by the Division of Forest Pathology, Bureau of
Plant Industry. Selections have been made from the most promising
forest strains of the Chinese hairy chestnut, Castanea mollissima,
and of forest types of the Japanese chestnut C. crenata. First-
generation hybrids between Asiatic and American species are usually
remarkable in vigor, ordinarily excelling all other hybrids in this
respect. Selective breeding has also been directed toward the
development of small-sized nuts useful in mast production on trees
that might be grown in soils not well adapted to either orchard
or forest planting.
The first comprehensive project in hybridization within a tree
genus was started in 1924 by the Oxford Paper Co., Eumford, Maine,
in cooperation with the New York Botanical Garden, New York,
N. Y. The primary purpose of this work was to produce new poplars
valuable for pulpwood reforestation (fig. 6). This work has been highly
successful. A total of about 13,000 hybrid seedlings was obtained
from about 100 different cross combinations between 34 different
* See Bibliography, published in the Yearbook separate of this article.
1250
YEARBOOK, 1937
Figure 6. — The Slrathglass poplar, one of the selected hybrid poplars produced by the
Oxford Paper Co., after 7 years of growth in the field. This tree is approximately 7
inches in diameter and 37 feet tall. It is rather heavily branched, but the branches
are small and should offer no difficulties to the use of the wood for soda pulp.
FOREST TREES
1251
species, varieties, and hybrids of poplars. The parents included 3 white
poplars, 5 aspens, 17 black poplars and cottonwoods, and 9 balsam
poplars or hybrids belonging in this group. Many of the new hybrids
appear especially promising because they surpass the older hybrids, at
least during the first 8 years of their life, in rate of growth, resistance
to disease and climatic conditions, and habit of growth (fig. 7).
Figure 7. — That well-directed breeding can produce trees immune or highly resistant
to tree diseases is demonstrated by these two poplar hybrids. The picture was taken
in early September. The trees at the right, without leaves, are members of a clone
which is highly susceptible to Melampsora rust disease. The trees at the left, in full
leaf, are members of a hybrid clone that is much more resistant to this disease.
These hybrids are the same age and have the same female parent but different
male parents.
Breeding work was undertaken at the Institute of Forest Genetics
in 1925 and the institute has now approximately 60 hybrid seedlings
involving 8 pine species and varieties as parents.
In 1930 the Brooklyn Botanic Garden, Brooklyn, N. Y., initiated a
project for the breeding of chestnut, to produce hybrids that would
combine good forest form with immunity to the chestnut blight.
Some of the hybrids that have been produced give promise of excellent
timber form and resistance to the disease.
The most recent large-scale breeding work was undertaken by
the tree crop unit of the Forestry Division, Tennessee Valley Authority,
Knoxville, Tenn., to develop trees that will combine good timber
qualities with the production of annual crops of fruit (nuts, acorns,
berries) of high quality and quantity. Such trees are to be used in
tree-crop plantings, where the fruits will produce an annual income
and the mature trees can be harvested for lumber or chemical wood.
1252
YEARBOOK, 193 7
The work of the Tennessee Valley Authority is of special interest
because it aims at an annual income for the forest or wood-lot owner.
For example, a stand of oak that will produce a large quantity of
acorns will probably more than pay its way to maturity bv the hog
feed they provide, and if this production can be combined with
excellent timber quality, forest planting to prevent soil erosion will
Figure 8. — Artificial hybrids between longleaf and slash pines produced at the South-
ern Forest Experiment Station show wide variation in susceptibility to brown spot (a
needle disease of longleaf pine) in the same plantation: A, A 3-year-old hybrid seed-
ling, highly susceptible to brown spot, has lost all of its older needles; B, another
hybrid of the same age, is relatively free from the disease and shows superior
growth and vigor.
be profitable to many southern hill-farmers. Improvement of our
best annual-crop trees by hybridization and selective breeding will
be essential to the successful and profitable combination of tree
crops and forestry on marginal and nonagricultural farm lands.
At the present time the NortheasternForestExperimentStation, New
Haven, Conn., is starting a project in forest genetics directed toward the
improvement of forest trees in the Northeastern region. It is expected
that the program will include practical and fundamental research on
seed origin, progeny tests, selective breeding, and hybridization.
Numerous other investigators in recent years have hybridized
species of forest trees to a limited extent. At the Southern Forest
Experiment Station, New Orleans, La., hybrid seedlings of Pinus
jmlustris X P. caribaea (longleaf and slash pines) were obtained in
1929 (fig. 8), and also hybrids between P. sondereggeri (itself a hybrid)
FOREST TREES 1253
and P. palustris and P. taeda, respectively. Workers at the Rocky
Mountain Forest and Range Experiment Station, Fort Collins, Colo.,
have successfully crossed individuals of a strain of ponderosa pine
that is apparently immune to mistletoe. At the Petawawa Forest
Experiment station, Petawawa, Ontario, Canada, red spruce and
Norway spruce were successfully hybridized in 1932, and in 1936
Populus canescens was crossed with P. tremuloides in an effort to
obtain a hardy aspen hybrid combining the wood characteristics
required for match and veneer wood with resistance to heart rot.
Breeding of forest trees is also being stressed in Europe. Larsen,
in Denmark, has been carrying on rather extensive breeding studies,
especially from the standpoint of self-pollination, and has published
his results in some detail. Von Wettstein, in Germany, has been
interested in the hybridization of poplars, particularly for the produc-
tion of trees especially suited to matchwood production. He has
developed and described a method for the maturation of hybrid
seed in artificial nutrient media. Liese, at Eberswalde, Germany,
working with Pinus montana (Swiss mountain pine) and P. sylvestris
(Scotch pine) failed to obtain hybrid seed between these species,
which are considered to produce natural hybrids quite frequently.
This failure, he concludes, may have been due to lack of "crossibility"
between the particular strains used, and the use of other individuals
might give positive results.
In addition to these strictly forest species, considerable breeding work
has been done with various nut trees, such as the walnut, of which
exceedingly vigorous hybrids are now in existence. This work is
described in the article on nut-tree breeding elsewhere in this Yearbook.
The outstanding improvement apparent in natural and artificially
produced hybrids between forest-tree species amply justifies particular
effort in this direction.
VEGETATIVE PROPAGATION
Vegetative propagation will be of great value for the immediate
utilization of exceptionally promising natural or artificially produced
forest trees. The rapid improvement of horticultural trees has been
possible because any new and improved type, hybrid or otherwise,
could be immediately multiplied as a clone by grafting, budding, or
other forms of vegetative propagation. With forest trees such as the
poplars and willows, which can be propagated by cuttings, the tree
breeder can utilize exceptional hybrids immediately with the assur-
ance that the individual members of such a vegetative clone will
exhibit the same inherent characteristics as the original tree, except
for mutations in the body cells of various parts of the tree. These
ordinarily occur so rarely that from a practical standpoint they are
unimportant. By such methods it is possible to retain any excellent
characteristic such as hybrid vigor — the exceptionally rapid growth
often inherent in first-generation hybrids — or any new character that
is due to an unfixed combination of complementary genes. Few forest
trees, however, can be commercially propagated by cuttings, and
although many species can be propagated vegetatively by grafting,
budding, or layering, these methods are not feasible at present because
of their comparatively high cost. It is essential to find cheaper
1254 YEARBOOK, 1937
methods of vegetative propagation if select hybrids or strains are to be
multiplied and utilized immediately for forestation planting.
A POSSIBLE APPROACH
TO THE IMPROVEMENT PROBLEM
Seed Origin and Individual Seed-Tree Progeny Studies
A search of the literature may leave the impression that investiga-
tions in the past have too strongly stressed the subject of seed origin
and seed-tree selection, and that the improvement of our forest trees
along these lines will be exceedingly slow. But from the standpoint of
immediate reforestation requirements, seed-origin and progeny studies
are of the greatest importance if the errors responsible for the poor
quality of many of the early European plantations are to be avoided.
According to Baldwin, approximately 25 percent of the forest stands in
Germany are inherently so poorly adapted to their environment that
the Government has ordered clear cutting to prevent their regeneration.
A program for the improvement of our forest trees that is concerned
with the immediate needs of general forestry may well contemplate
studies on seed origin, delineation of races and strains of species and
varieties, individual seed-tree progeny studies, and adaptability of
exotics on a larger and more intensive scale than in the past. Al-
though such studies are especially necessary to determine the best
races or strains for forestation, the data derived from them will also
be of great value for improving the inherent qualities of natural forest
stands by silvicultural methods. Criteria for the selection of good
breeding stock, that is, for differentiating environmental and heredi-
tary characteristics, are essential to good silvicultural practice in our
natural stands. Improvement cuttings, thinnings, and especially
selective logging, are probably the forester's best approach to muss
selection, which will improve the inherent quality of our wild forests
in direct proportion to the ability of the silviculturist to identify the
select stock and leave it for seed purposes.
There is evidence that in our forest trees many valuable inherent
characteristics are still to be discovered and isolated. A list of char-
acters in which differences between individual trees of the same
species have been reported as apparently hereditary is included at
this point, because it indicates the range of hereditary variation and
the possibilities in selection from our present wild stocks.
Rapidity of growth.
Growth habit.
Crown and stem form.
Leaf size, form, and color.
Growth periods.
Nut qualities and length of catkin.
Yield and composition of resin.
Proportion of resin adhering to faces as "scrape."
Color and correlated quality of wood.
Fiber length in wood.
Physical and chemical properties of wood.
Twisted grain in wood.
Resistance to frost, heat, light, and snow.
Resistance to disease and mistletoe.
Resistance to insects.
« This refers to the gum adhering to the wood exposed in turpentining, reducing the final yield appreciably.
FOREST TREES 1255
These characters include not only those that are desirable from the
standpoint of the forester (the producer), such as rapid growth and
resistance to climatic conditions, disease, and insects, but also quali-
ties important to the consumer, such as straightness of trunk and
properties of the wood. Selection must be based on the requirements
of the grower and the requirements of the user — so-called forest
requirements and use requirements, respectively.
The silviculturist must look to the forest geneticist for possible
correlations between readily recognized characteristics of the indi-
vidual tree and its capacity for producing desirable progeny. Such
correlations, even though they are only approximate, will be of great
immediate value. This is especially true because the forester, man-
aging a natural stand under a proper selection system, usually has an
overabundance of seedlings, only a small percentage of which will be
brought to maturity. If selection is for vigor of growth, the inher-
ently vigorous individuals will normally take the lead and should make
up a large proportion of the final crop. If other characteristics or
qualities are desired, the forester using a selection system has oppor-
tunity to rogue his stand with each cutting or thinning, and unde-
sirable individuals can be eliminated as their mature qualities become
apparent.
Since the recognition of inherent quality is a key to the improvement
of vast forest stands which for various reasons, such as inaccessibility
or difficult environmental conditions, are not adapted to intensive
forestry, well-planned investigations on this problem are justified.
Much of the groundwork will not be strictly genetics. It will first be
necessary to define clearly the desired characteristics or qualities.
The relative desirability of particular qualities or characteristics will
depend upon many things, including the species; the locality where
it is to be grown ; the purpose for which it is grown — watershed pro-
tection, soil-erosion control, tree crops or wood; and probable utiliza-
tion— lumber, chemical wood, etc.
After the desired characteristics have been defined, methods for
their accurate description or measurement must be devised. If
measurement is not possible, then descriptions that will adequately
bring out existing differences should be available. Rapidity of growth,
usually a most important consideration in forestry, is easily measured.
Measures for resistance to disease, insects, and climatic conditions will
be fairly easy to develop. On the other hand, tree form or branching
habit, very important from the standpoint of lumber quality, has been
much debated but seldom adequately described or measured. Wood
quality is even more elusive; "test-tube" methods for determining
the physical and chemical qualities of wood are urgently needed.
Tests that require cutting down the tree cannot be used to advantage
by the forest geneticist, since a felled tree obviously cannot be used in
breeding.
The progeny test is the generally accepted measure of inherent
(breeding) quality. As applied to forest trees the method usually
involves knowledge of the female parent only, since the seed is set by
open pollination. Seed is collected from selected seed trees and the
performance of the progenies of the individual seed trees is used as a
criterion of breeding quality. This method eliminates the expense and
1236
YEARBOOK, 193 7
time involved in making controlled pollinations (fig. 9), but since the
male parent is unknown the results must be interpreted with caution
and can never provide exact genetical data on the mode of inheritance.
This one-parent method may provide partially correct answers some-
what earlier than more exact methods, but a careful analysis of individ-
ual seed-tree progeny tests, which have been under way for a period of
Figure 9. — Controlled |K>llination technique developed for work with pines at the
Institute of Forest Genetics. A finely woven canvas bag with transparent window is
placed over the flowering branches before the female flowers come into bloom. The
sulphurlike pollen of the desired species of pine is placed in the barrel of a hypodermic
needle and injected into the bag containing the ovulate flowers. The transparent
window in the bag enables the operator to determine when the flowers are in the
receptive stage and ready to receive the pollen.
years, will be highly desirable before further extensive trials of this
kind are started.
Progeny tests involving full control of parentage are required to
provide accurate data on heritability and mode of inheritance of
particular characteristics. With this method both the male and the
female parents are known. Self-fertilization, where possible, will be
the quickest method of evaluation, but it is to be recognized that
selfing in plants that naturally cross-breed often leads to degenerate
lines, with loss of vigor. This must be considered in pure line breeding
with forest trees which are apparently continually cross-pollinated.
Selective Breeding and Hybrddization
Improvement by selection of the best individuals or strains from the
wild stock is limited in scope. This procedure can hardly result in
improvement of our best forest trees in the strict sense of the word,
since the essence of the selection process is a sifting out of undesirable
types and a segregation of the best strains already in existence.
FOREST TREES 1257
Hybridization and selective breeding aim beyond this point and
attempt to develop new types, which combine the desirable charac-
teristics present in two or more individuals often widely separated
geographically and sometimes racially. This possibility can be demon-
strated in the hybrid progeny of a controlled cross-pollination,
carried out at the Institute of Forest Genetics, between Pinus atten-
Figure 10. — Hybrids of knobcone and Monterey pines combine the frost resistance of
one species and the vigor of the other. The short tree on the right represents the
hardy but slow-growing knobcone pine. Beyond it are two trees of the badly frosted
but rapid-growing Monterey pine. On the left are three hybrids of these two species.
They have about the same vigor as their pollen parents, the Monterey pine, and are
practically as hardy as their seed parent, the knobcone pine. All trees are 4 years
old from seed.
•uata (knobcone pine) and P. radiata (Monterey pine), which combine
the rapid growth of the pollen parent with the frost resistance of the
seed parent (fig. 10) ; or in the Dunkeld larch, which is said to combine
the excellent growth qualities of the European larch with the resistance
to larch canker inherent in its Japanese parent. Cross-breeding may
also result in the creation of entirely new characteristics, the expression
of combinations of genes that would never occur under natural condi-
tions. As has already been said, hybridization and breeding have
infinite possibilities, but they are only at their beginning in forestry.
A proper appreciation of breeding methods must be based upon
the realization that the plant breeder is concerned with individual
plants; that particular characteristics or qualities of the individual
are of primary importance; and that the factors or combinations of
factors in the germ plasm, which are responsible for the particular
characteristics, are the raw materials that the breeder must shape
into his ideal plant. With this in mind it is obvious that the most
rapid progress in forest-tree improvement necessitates accurate
information on the expression and behavior of the hereditary units
in our various forest-tree species.
Mass Selection
In mass selection, groups of plants with more or less uniform charac-
teristics are permitted to intercross. Close control of parentage is
impossible, and gradual improvement results from continued selection
of breeding stock on the basis of apparent quality. Improvement is
138904°— 37 80
1258 YEARBOOK, 1937
usually rather slow and the method does not provide accurate data
that can be utilized for further breeding. The results attained depend
to a considerable extent on the judgment of the breeder in selecting
seed plants, and especially on his ability to distinguish between the
effects of heredity and of environment. As noted previously, for the
present this method seems best adapted to the improvement of natural
stands that are to be handled under a selection system.
One-Parent Progeny Tests
The evaluation of the inherent quality of an individual tree on the
basis of the progeny derived from uncontrolled pollination has already
been discussed. The fact that only the female parent is known and
that the unknown male parent has contributed half the germ plasm
of the progeny considerably restricts any interpretation of the results.
The method can probably be recommended only for preliminary survey
purposes or where personnel is inadequate for the application of a
more accurate procedure.
Pedigree Breeding Within and Between Varieties,
Species, and Genera
Pedigree breeding with full control of parentage has been described
in many of the articles in this and the 1936 Yearbook of Agriciilture.
Here both parents are known, and the progeny derived from selfing and
from well-planned crosses provide an accurate measure of the respec-
tive parental germ plasm. Investigation by this method will not only
determine which characteristics are inherent, but will also indicate the
mode of inheritance — information that is indispensable for far-reaching
improvement by intensive breeding and hybridization. The following
discussion indicates pedigree methods applicable to forest trees.
Pure-line breeding, by selfing, is usually the most rapid method for
the evaluation of hereditary characteristics. This will be possible
only with trees that are hermaphrodite and self-fertile. In breeding
trees that produce male and female flowers on separate individuals,
or hermaphrodite trees that are self-sterile, crossing between selected
individuals is necessary. With trees of this nature the nearest approach
to pure-line breeding is to cross parents possessing the same characters,
that is, breeding within a strain, variety, or species. Pure-line breeding
and cross-breeding within a variety or strain will provide fundamental
genetical data for the evaluation of inherent quality and the mode of
inheritance, and may also provide superior races and strains for foresta-
tion. These superior types will be a source of superior germ plasm of
known breeding value for further hybridization and breeding.
Combinations of desirable characteristics and modifications or new
expressions of characters, due to new combinations or rearrangements
of the determiners of heredity, are possible by cross-breeding between
pure lines or varieties (intervarietal or intraspecific hybridization).
Intervarietal crosses ordinarily represent the least difficult kind of
hybridization. Varieties usually cross quite readily and produce fertile
offspring. Valuable results may be apparent in the Fi or first hybrid
generation, and segregation in the F2 or second generation (Fi plants
selfed or crossed) will produce new combinations from which the best
individuals can be chosen for further selective breeding.
FOREST TREES 1259
Crosses between different species of forest trees — a more remote
relationship than between varieties — offer interesting possibilities.
Such interspecific hybridization is often complicated by the fact that
two species are difficult to cross, or by the partial or complete sterility
of the resulting hybrids. If two species cannot be crossed directly it
is at times possible to include them in the parentage of the final hybrid
by breeding through a third species. In fact the utilization of "three
or more species in the breeding of daylilies has produced particularly
valuable hybrids.
The first-generation hybrids of two forest-tree species are often
quite uniform and more or less intermediate between the parent
species. Segregation and recombination of characteristics occur in
the second generation, and it is this generation that provides a very
wide diversity of material for selective breeding. The procedure indi-
cated is, therefore, (1) a small first-generation population, but (2) a
large second-generation population, with (3) selective breeding con-
tinued with the most promising individuals of the second generation.
Interspecific hybridization of our forest trees is entirely justified,
because it offers immediate improvement by combinations of desirable
characters and the possibility of entirely new characteristics or quali-
ties resulting from combinations of determiners that have never
before been combined in any germ plasm. Many first-generation
hybrids are more vigorous than either of their parents. This so-called
hybrid vigor and any other valuable character can be maintained and
utilized immediately if vegetative propagation is possible. Hybridi-
zation followed by polyploidy has also created individuals with
unusual chromosome numbers that are superior to their parents and
have their characteristics "fixed" so that they come true from seed.
Genera are, of course, even more distantly related than species.
The comparatively few intergeneric plant hybrids that have been
produced up to the present time have not been of practical value.
Intergeneric hybridization is very greatly ■ limited by specific differ-
ences in the requirements for fertilization inherent in distantly related
plants. Furthermore, the progeny are seldom fertile. In spite of
the difficulties involved, crosses between different genera may lead
to valuable results, and excursions in this direction are warranted.
The Time Element in Tree Breeding
The improvement of forest trees by breeding and selection might
appear, at first sight, to require centuries for completion. But al-
though the work often requires a considerably longer time for the
successful production of improved stocks than similar work with
annual plants, various short cuts are possible.
. The time element in breeding is dependent among other things on
the relative age at which the individuals begin to bloom. Many trees
produce flowers early in life — 7-month-old chestnut seedlings occasion-
ally bloom in nursery beds; fruit is often produced on chestnut trees
before they are 5 years old; 4-year-old pines have been observed to
mature cones; first-generation poplar hybrids 7 years old from seed
have produced flowers and fruit. The blooming of more slowly ma-
turing trees can usually be hastened by top-working or grafting on
closely related mature individuals, and possibly in some species by
1260 YEARBOOK, 1937
ringing, a light girdling of the trunk. Further work to determine the
possibility of lowering the blooming age would be well worth while,
since early blooming permits further cross-breeding or inbreeding and
eventually speeds up the entire improvement program.
In order to take advantage of early blooming, correlations between
juvenile and mature characteristics must be discovered. The fact
that a tree blooms at an early age is of no value unless its character-
istics at maturity can be predicted with fair accuracy. Such qualities
as resistance to disease and winter hardiness can usually be deter-
mined with young trees, but in breeding for good forest form (habit
of growth) it will be necessary to recognize and select for further
breeding the young individuals that will develop good form at maturity.
The possibility for early results is indicated by the fact that selective
breeding with daylilies, based on a knowledge of the mode of inherit-
ance within the group, has fixed new combinations of germ plasm,
derived from as many as four distinct species, into new types in five
generations (Stout, 1936).*
Increased Chromosome Numbers, Polyploidy,
Aneuploidy, and Mutations
Many valuable types of cultivated plants have arisen through an
increase of chromosomes, originating in the somatic (body) cells,
in the germ cells, or in the earliest divisions of the fertilized egg.
The increase may consist in the duplication of a single chromosome,
an unbalanced condition referred to as aneuploidy; or the chromo-
somes may be duplicated in multiples of the basic number (polyploidy).
There may be multiplication of the chromosomes of a single individual
(autopolyploidy), or a multiplication of both of the parental chromo-
some complements of a hybrid (allopolyploidy). Individuals with
unbalanced chromosome complements may be maintained and multi-
plied as clones if vegetative propagation methods can be used.
There is evidence that merely a quantitative increase in chromatin
material may be responsible for wide differences in characters that
are of great practical value, and that polyploidy in hybrids, involving
a quantitative increase in the chromatin material received from both
parents, can produce new types as distinct as many of our present
species. Polyploidy may result advantageously in (1) increased
vigor; (2) increased variation; certain types of polyploidy may also
give (3) increased fertility; (4) stability — that is, new types may breed
true. On the other hand, polyploidy is sometimes directly responsible
for increase in cell size, a contingency that is of particular significance
since the chief product of forest trees is wood. An increase in the
size of the wood fibers would be detrimental to the physical properties
of some woods and would limit the use of others now used in the
manufacture of particular grades of paper.
Of especial interest to forest-tree breeders are the facts that poly-
ploidy has been induced by physical treatment of both somatic
(body) and germinal tissue and by hybridization, and that balanced
polyploids may breed true. If a superior self-fertile individual of
this nature can be developed by physiological methods or by hybridi-
zation, it can immediately be propagated by seed. Such a strain
6 See Bibliography, published in the Yearbook separate of this article.
FOREST TREES
1261
would probably not cross readily with the native species and might
thus maintain itself unmixed (homozygous) under natural conditions.
The possibilities justify intensive effort directed toward the creation
of polyploid strains.
New variations of the nature of mutations and bud sports, involving
basic changes in the chromosome complement other than those due
to duplication, occur occasionally in forest trees. The Lombardy
poplar is said to be a mutant form of the European black poplar
(Populus nigra) and the weeping beeches and birches are probably of
similar origin. Although such variations have been primarily of
value as ornamentals, it is possible that individuals of particular
value for forestation purposes may be discovered.
Advantages in the Use of Vegetative Propagation
If vegetative propagation is feasible, any superior individual can
be multiplied immediately and its characteristics perpetuated by the
establishment of a clone. By vegetative propagation the breeder can
Figure 11. — One season's growth from roots of poplar hybrids cut back annually for
the production of cuttings. The measuring rod is 9 feet high.
take advantage of the excellent individuals that may be produced at
any stage of the breeding work, and since the components of the genu
plasm are maintained in the somatic condition, the difficulties due to
segregation of superior chromosome combinations are eliminated.
Many so-called species are actually clones, and the uniformity among
the individuals is due to the fact that the genetical complex is always
passed on exactly as it was in the original plant.
Vegetative propagation does not lead to degeneration in clones.
Investigations on cases of supposed senescence in clones have proved
1262
YEARBOOK, 193 7
environment or disease-producing
that outside agencies such as
organisms have been responsible.
The most promising hybrids produced in connection with the
breeding project of the Oxford Paper Co. have been rapidly multiplied
from cuttings at a unit cost lower than that of northern-grown nursery
stock. Some idea of the rapidity of propagation by means of dormant
cuttings may be gained from the fact that in Maine, with a compara-
tively short growing season, a 1-year-old poplar hybrid will produce
10 to 20 cuttings, at 2
years, 40 to 60 cuttings,
and that after 3 years it
will continue to produce
100 to 200 cuttings annu-
ally (fig. 11). If neces-
sary, the rate of multipli-
cation can be further
increased by propagation
from softwood cuttings.
By this method small
twigs 4 to 6 inches in
length, cut from the
mother plant throughout
the growing season, are
rooted in shaded, moist
sand beds.
Intensive investiga-
tion to develop a cheap
method for the vegeta-
tive propagation of forest
species that cannot now
be economically repro-
duced in this way is fully
justified; the best of our
present wildlings and
the elite individuals pro-
duced through breeding
can then be utilized with-
out further delay.
Need of Developing
Technique
in pines m-
Figure 12. — Controlled hybridization
volves physical difficulties. This 77-foot ponderosa
pine has 100 bags protecting the ovulate flowers from
wind pollination.
As in every new line
of research, technical
difficulties must be over-
come before extensive breeding work can be undertaken. The breeder
of forest trees is not only faced with the physical difficulties incident
to the necessity of working with flowers at the tops of large trees
(fig. 12), and often on the outside branches, but he is also handi-
capped at the present time by lack of accurate information essential
to his work. Practically nothing is known of flower behavior, pollen-
storage possibilities, artificial pollen-germination methods, sterilities,
and incompatibilities in forest trees, and the affinities between species.
FOREST TREES 1263
Accurate and detailed data on the flowering period of parent trees
are essential for the successful planning of a breeding project. Infor-
mation on blooming dates is not always sufficient ; the receptive period
of the female flowers is of vital importance in breeding. Where
dichogamy, or the ripening of male and female organs at different
times, occurs, it often necessitates storing pollen until it can be used,
and since pollen viability in different species is known to vary from a
few days to over a year, data on this point should be available. Assum-
ing that the pollination has been made with viable pollen at the proper
time and under favorable climatic conditions, incompatibilities or
sterilities may still cause failure, and success can be attained only
through a thorough understanding of such conditions.
The breeder of agricultural plants usually has more or less proven
varieties and strains available that can be grown in adjacent plots
in his experimental grounds. The breeder of forest trees must
work with a wide diversity of species and varieties and often
with widely scattered parent stocks — desirable parent types may
be located hundreds of miles apart, and at best they are seldom
within walking distance. Crossing such trees often requires the
development of a new technique.
FUNDAMENTAL INVESTIGATIONS "
Fundamental genetical studies should certainly be started with
forest trees. Chromosome studies and other cytological work nec-
essary to a thorough understanding of the particular physical pro-
cess involved in the transmission of hereditary characteristics in
trees will be indispensable to the tree breeder. Cytological data
will be an immediate necessity for effective work directed toward
the compounding of polyploids. The solution of many problems will
require the combined efforts of the geneticist, the cytologist, and the
physiologist.
The forest geneticist should lay a broad foundation for such funda-
mental studies, but in doing so he should not overlook the fact that
much of his early work must of necessity be more or less empirical in
nature. It is generally recognized that the mode of inheritance of any
particular character can seldom be predicted from a cytological study
of the parents used; only actual crossing can supply the answer. It
will be largely on the breeding work of the forest geneticist of today
that the forest geneticist of tomorrow can safely continue his funda-
mental research, with the assurance that his line of attack is in the
right direction.
A questionnaire on the subject of improvement in forest trees, which
was submitted in connection with this Yearbook to various individuals
and organizations both in the United States and abroad, asked for an
opinion on the outstanding technical and practical problems that
remain to be solved. In order to present the views of individual
workers in various parts of the country with respect to their particular
problems, it seems advisable to include their recommendations on
genetical problems verbatim.
7 The following section is intended primarily for students and of hers professionally interested in breeding
or genetics.
1264 YEARBOOK, 1937
Lloyd Austin. California Forest and Range Experiment Station,
Institute of Forest Genetics, Placerville, Calif.
Adaptability of selected strains and progenies. — While quite a little preliminary
work has been done by the institute and other organizations in testing in a general
way the adaptability of various forest species, only a bare beginning has been made
in the formidable task of adequately testing and retesting the various selected
strains and progenies of these species that are gradually being discovered. There
can be no one best strain for all localities, and, as superior types are isolated by
progeny tests and other methods, it will become imperative to try these out in a
comprehensive way and under various climatic and soil conditions, so that eventu-
ally the best forms for each locality will be definitely known.
Hybridizing within species to combine vigor and cold-hardiness. — The institute's
results seem to indicate that, at least in the case of Pinus ponderosa, most of the
seed trees having the greatest inherent vigor will probably be found at relatively
low elevations. Although proof is not yet available, it seems highly probable that
these low-altitude forms will lack the degree of inherent cold-hardiness possessed
by the forms from the higher elevations where much lower temperatures are
encountered. This opens up a most promising line of genetical research in which
artificial crosses would be made between low- and high-altitude strains, utilizing
as parents in both cases the individual seed trees that the progeny tests show to be
hereditarily superior. In this way it should prove possible to combine the rapid
growth rate of one form with the desired cold-hardiness of the other, and thus
greatly increase the adaptability and usefulness of the vigorous types. The
institute has already accomplished practically this same combination of characters
in the case of its cross of P. atlenuata and P. radiata, and it should prove much
easier to cross different altitudinal forms of P. ponderosa than to cross distinct
species, which is nearly always difficult of accomplishment.
Improving the quality of seed from selected native seed trees. — Another promising
line of genetical inquiry well worthy of investigation would consist in making
tests in relatively isolated field plots to determine the practicability of using a
carefully regulated thinning to improve the quality of the seed from the germinally
superior individuals. The plan would be to cut out all those seed trees that the
progeny tests show to be inferior. In this way subsequent natural cross-pollina-
tion would take place largely between the better types and seed with improved
heredity should result. Such seed would be highly valuable for actual work in
reforestation.
Roy L. Donahue. Mississippi State College, State College, Miss.
I would say that the needs for this region in particular with reference to forest
genetics should include a testing of the various strains of black locust, especially
different strains varying as to seed source.
Another type of research needed in Mississippi as well as throughout the entire
South is in relation to the selection and breeding of a first-class Christmas tree.
At the present time Christmas trees of excellent quality are imported from as far
away as the West coast.
Duncan Dunning. California Forest and Range Experiment Station,
Berkeley, Calif.
Studies should be made of the heritability of crookedness, excessive branching,
spiral grain, and susceptibility to diseases.
Arthur H. Graves. Brooklyn Botanic Garden, Brooklyn, N. Y.
The most important of these requirements for rapid progress in forest tree
improvement is reproduction by asexual methods — cutting, layering, budding, and
grafting.
C. Ileimburger. Petawawa Forest Experiment Station, Chalk River,
Ontario, Canada. Urgent research problems:
The finding of a suitable strain of Norway spruce for pulpwood production,
especially for the spruce regions in eastern Canada.
The finding of suitable strains of Scotch pine to replace jack pine, on sites not
suitable for other more valuable native pines.
FOREST TREES 1265
The production of a fully hardy rapidly growing aspen hybrid, combining the
useful characters of the native aspens with added resistance to heart rot and better
wood quality for the production of match stock and veneer.
A suitable propagation method for aspen poplars and their hybrids, better than
the usual root-cutting methods.
Richard E. McArdle. Rocky Mountain Forest find Range Experiment
Station, Fort Collins, Colo.
Other practical problems which demand solution involve the development or
isolation of drought-resistant strains of native species (particularly ponderosa pine)
for planting in the sand hills of the Plains States and in the high plains dry-land
country immediately east of the mountains; determination of the best strains of
Engelmann spruce and possibly other species for planting on denuded subalpine
sites in the spruce type in Colorado, also in the bristlecone pine and limber pine
types where administrative restrictions have been imposed upon the planting of
native soft pines because of the blister-rust menace ; improving lodgepole pine from
a pathological standpoint to cut down losses in merchantable stands. While
these problems are practical in their scope, their solution can follow only along
highly technical lines of approach. This will require, therefore, the solution
of technical problems either directly or under the supervision of qualified
geneticists.
T. E. Maki. Intermoimtain Forest and Range Experiment Station,
Ogden, Utah. Urgent research problems:
Determination of the inherenlness of heavy or light seed producers.
Determination of vigor, natural pruning habit, etc., of progeny from different
tree and ago classes.
F. I. Riyhter. California Forest and Range Experiment Station,
Institute of Forest Genetics, Plaeervillc, Calif.
Breeding with polyploids. — In pine breeding projects the problem of inducing
totraploidy in hybrids may well be regarded as second to none in importance.
The production of such forms, which, having their origin in hybridization, are yet
something more than hybrids — namely, amphidiploid hybrids — will yield the
following advantages: (1) Prolonged and costly selection tests of the F2 and
succeeding generations wonld be avoided; (2) such forms often are more vigorous
than the parental species; (3) they are endowed with higher degree of fertility; (4)
insofar as practical purposes are concerned, they breed true; and (5) when they,
in turn, arc hybridized the F2 generation will consist of greater varieties of new
forms for investigation than does the F2 of the ordinary species or varietal
cross.
Polyploidy has not been reported for the pines, and it probably will be necessary
to induce tetraploidy before any further breeding with polyploids will be possible;
however, the tetraploids should constitute sufficient justification in themselves for
work in this field. The possibility of realizing the benefits which may be expected
from the production of amphidiploid hybrids is not more remote than is that of
achieving comparable results through selection tests subsequent to hybridization.
In fact, the latter method of proceeding may well be regarded as the last desperate
resource in the field of hybridization with pines, whereas the former offers such
valuable results that its immediate adoption is fully justified.
Tetraploidy has developed in sterile species hybrids spontaneously but such
appearances have been so rare that it will not be practicable for the pine breeder to
rely on the production of such forms through the operation of Nature alone.
Artificial means are practically a requisite for such work. Fortunately, means of
inducing tetraploids have been developed. The chief method developed thus far
consists of subjecting the zygote to heat treatments during the first few cell
divisions following fertilization. Under the influence of such treatments a newly
formed embryo may undergo nuclear division without the laying down of a divid-
ing wall. This process results in the formation of a cell having the double number
of chromosomes. The further growth of the embryo results in an individual that
is entirely tetraploid. Attempts to induce tetraploids in hybrids may prove
difficult at first, because of the difficulty of ascertaining when fertilization occurs,
1266 YEARBOOK, 1937
for in most of the pines fertilization occurs about a year after pollination; however,
the problem should yield to the combined attacks of the geneticists, the cytologist,
and the physiologist.
Cytological, taxonomical, and physiological studies. — Cytological, taxonomical,
and physiological studies of the genus Pinus will contribute immeasurably to the
progress of the work of breeding superior timber trees, because they ramify into all
phases of the work. Such studies will be started in the near future.
Paul 0. Rudolf. Lake States Forest Experiment Station, St. Paul,
Minn.
As far as forest genetics goes, the field has barely been scratched. So many
problems remain to be solved that it is difficult to know where to begin in listing
what remains to be done.
From the practical standpoint it seems desirable to extend source-of-seed tests
to include all species used in forestation work to indicate within what limits seed
can safely be used in other than native localities for various species. The selec-
tion of individual trees and stands of particularly desirable characteristics, followed
by the determination of the extent to which these characteristics are heritable
by their progeny, is another useful field of investigation. Cross-breeding and
hybridizations which have been begun with certain early-maturing species of
Populus, Salix, and Larix here and abroad might well be extended to other species
in general although the immediate practical value may not be as great as for other
studies.
In the field of pure genetics much of value might bo accomplished by a study of
the mechanics of inheritance for important tree species particularly with a view
to determining how certain desired characteristics are transmitted and to what
extent such functions may be modified or controlled.
Philip C. Wakeley. Southern Forest Experiment Station, New
Orleans, La.
Further work upon the pines (to say nothing of the hardwoods) is urgently
needed in:
a. Effect of climatic-zone source of seed.
b. Effect of major soil typo source; e. g., deep sands.
c. Effect of female parent source alone on progeny (of direct application in
seed collection) .
d. Effect of both parents upon progeny (of direct application in marking for
natural reproduction cuttings) .
e. Development of very tall strains for high yields, structural timber, and
piling.
f. Development of strains high in naval stores yield.
g. Development of brown spot-resistant P. palustris, windfirm P. caribaea,
and tip moth-resistant P. iaeda and P. echinata, for artificial reforesta-
tion.
APPENDIX
As a part of the cooperative sxirvcy of plant and animal improvement, a compre-
hensive questionnaire requesting information on investigations pertaining to
improvement in forest trees was sent to approximately 150 institutions and
private agencies in various parts of the world. Summaries of the reports received
from those organizations or individuals engaged in work of this nature are included
here. The replies received present a rather complete account of forest-tree
improvement work in progress throughout the United States, but the replies from
foreign sources are rather limited.
United States — Federal Agencies
Bureau of Plant Industry, Division of Forest Pathology
3. Hybmidization
Progeny of the following crosses, being grown for forest-tree improvement, arc
under observation:
Castanea mollissima X C. denlata, 272 seedlings 1 to 8 years old.
C. crenata (forest types) X C. dentata, 33 seedlings 1 to 4 years old.
FOREST TREES 1267
C. crenata (forest types) X C. mollissima, 44 seedlings 1 to 5 years old.
C. mollissima X C. henryi, 10 seedlings 1 to 9 years old.
C. crenata (forest types) X C. henryi, 3 seedlings 1 to 2 years old.
In general, hybrid vigor is present in these first-generation trees in the order as
listed.
Progeny of the following crosses apparently should be valuable in the production
of mast crops and for soil conservation planting:
C. pumila X C. seguinii, 21 seedlings 1 to 5 years old.
C. mollissima X C. seguinii, 19 seedlings 3 to 0 years old.
C. crenata X seguinii, 24 seedlings 1 to 6 years old.
Reciprocal crosses are usually made as a matter of routine. From the genetic
viewpoint no significant differences have been found in their progeny. Seedlings
of crosses with a dwarf Chinese chestnut, C. seguinii, tend to be everblooming
in habit, a dominant character inherited from that species. Additional crosses
are being made between the several American chinquapins and the various true
chestnuts from Asia. Here again selections will be made of individuals suitable
for mast-crop production and soil-conservation planting, but such selections are
not expected to carry the everblooming habit.
Present work is now largely confined to the production of second-generation
stock and incidentally to the study of genetic phases of the problem with special
regard to the inheritance of resistance to the chestnut blight.
Forest Service, Appalachian Forest Experiment Station 8
1. Seed Origin
Robinia pseudoacacia (black .locust)
One-year-old seedlings from seed collected from seven Appalachian sources
(West Virginia, Virginia, North Carolina, 1,800 to 3,000 feet elevation) were set
out in test plantations at Bent Creek in 1935. Seed from an additional five
sources (three foreign, two American) was used to establish test plots in South
Carolina, West Virginia, North Carolina, and north Georgia in 1936. In both
experiments significant differences between the average height of seedlings from
different sources were observed at the end of the first season's growth. Some
difference was also indicated in form of bole.
In the fall of 1935, 20 superior and 20 average seedlings were selected in each of
10 nurseries (in North Carolina, South Carolina, Tennessee, Mississippi, Virginia,
and West Virginia). These were planted in test plots in the Bent Creek Experi-
mental Forest in 1936 to determine the possibility of selecting superior strains from
1-year-old seedlings.
2. Individual Seed- Thee Progeny Tests
Pinits taeda (Loblolly Pine)
Seedlings from 122 individual seed trees were out-planted in 1936 for progeny
study. The purpose of this experiment is to determine the effect of the female
parent on the germination and growth of seedlings, with the ultimate aim of
determining the desirable characteristics of loblolly pine seed trees.
California Forest and Range Experiment Station,
Institute of Forest Genetics
1. Seed Origin
Extensive tests of species and geographical races are well under way. The
arboretum contains approximately 100 species and named varieties of the genus
Pinvs and inumerable climatic forms of many of these species; seed has been
obtained from 40 countries. Growth records', taxonomic records, phenological
records, injury records, and seed, sowing, and germination records are taken on
all of these test trees, which range in age from 4 to 15 years. Among the fastest
growing species so far tested are P. radiala (Monterey pine), P. pinaster (cluster
pine), P. taeda (loblolly pine), P. coulteri (Coulter pine), P. patula (Toluca pine).
In most tests P. radiala has surpassed all other species in rate of growth, particu-
larly in height growth.
The great majority of all the pine species tested have possessed sufficient cold-
hardiness to enable them to survive at the institute at Placcrville, Calif., where
»At Asheville, N. 0.
1268 YEARBOOK, 1937
the lowest temperature on record is 16° F. Exceptions have occurred in the case
of certain tropical species, such as Pinus tropicalis, P. insularis, P. canariensis,
and P. merkusii. These species do not seem to possess enough inherent resistance
to cold to be of practical value in any of the important forest regions of the
United States, but they are of interest to tree breeders who may wish to hybridize
them with hardier species.
Tests with approximately 30 species of pine are under way in cooperation with
numerous organizations (31 in the United States and 1 each in England, Scotland,
and Denmark) to determine the adaptability of the various native and foreign
species.
In addition to the work with pines, 35 species of conifers, representing 17 genera,
and 20 species of hardwood trees, 13 genera, are included in the arboretum.
These investigations will eventually indicate the value and adaptability of
geographic races and strains of many important timber trees, and the arboretum
will be a source of superior germ plasm for future selection and breeding work.
2. Individual Seed-Tree Progeny Tests
Progeny tests have been undertaken with 10 species and varieties of pines.
All seed is collected from tagged seed trees, which are fully described and have
their location recorded in map form. Seed has been gathered from a total of
2,609 separate trees located in 289 field plots. Many thousands of seedlings have
been grown in the nursery and of these 1,843 progeny trees have appeared worthy
of further trial in forest plantations to test the permanence of the early differences
apparent in the nursery.
As rapidly as the desirable seed trees are discovered, they become for many
years potential sources of relatively large quantities of superior seed for practical
reforestation. Trees selected in this way are also valuable for use in breeding
experiments designed to develop still better types.
P. ponderosa (ponderosa pine)
The largest single progeny test was started in 1929 with seed from 742 individual
trees of this species and its varieties scopulorum and jeffreyi. (Pinus jeffreyi is
considered a separate species by Sudworth in his Check List of the Forest Trees
of the United States.) The seed trees represented in this test are scattered over
60 counties in 12 Western States and British Columbia.
Results already indicate that within this species and its varieties there are
innumerable local strains, each with distinct morphological and physiological
characteristics. _ Even within a local geographical strain, individual seed trees
vary strikingly in their ability to produce seedlings that are superior in vigor and
in habit of growth.
Although the hereditary vigor of ponderosa pine in the central Sierras of Cali-
fornia tends to decrease markedly with an increase in the elevation of the seed
source, certain individual seed trees have been found at relatively high elevations
which, contrary to the general tendency, have high inherent vigor. These are
of outstanding value since they probably have the ability to produce offspring
that will be both fast-growing and cold-hardy.
Eldorado County, Calif., seems to be about the center of the optimum belt for
ponderosa pine, and an intensive progeny test is to be started in the spring of
1937 using seed already collected from about 1,000 trees growing in this county
and closely adjoining areas. Seed-collection activities have been so directed that
there has resulted a relatively complete sampling of the local strains within this
limited area. The field plots are distributed over an altitudinal range of more
than 8,000 feet, extending from an elevation of 150 feet up to 8,400 feet.
It is hoped from these various progeny tests to determine whether or not there
are any correlations between the visible characters of the seed trees and the nature
of their progenies, and to ascertain any relationships that may exist between the
environment of a seed tree and the growth, hardiness, etc., of its progeny.
Juglans (walnuts)
Walnuts are being studied primarily from the point of view of developing
superior timber trees, and their nut-producing characteristics are a secondary
consideration in these experiments. Tests have been undertaken with the
progenies of 272 individual trees of 16 species and hybrids of walnuts. After
growing the progenies for 2 years in the nursery, 421 seedlings were selected and
FOREST TREES 1269
set out in permanent plantations. There have been marked differences in the
growth of the different progenies.
In some cases natural cross-pollination between species apparently took place
during the spring prior to the collection of the nuts, for certain nonhybrid seed
trees yielded progenies that were partly hybrid in nature. The nuts were graded
into three sizes before sowing, and it was later discovered that most of the hybrids,
some of which were very vigorous, came from the large nuts. Hybridization
apparently stimulated the development of the nuts, and this may provide a simple
method for selecting a high proportion of naturally hybridized "nuts from walnut
trees exposed to pollen of other walnut species.
3. Hybeidization
Controlled hybridization has been a very important part of the work carried
on at this station.
Progeny of the following artificial crosses (made at the institute) are under
observation:
P. attenuata (knobcone pine) XP. radiata (Monterey pine). Rybridity certain.
Progeny, 8 years old, shows rapid growth of pollen parent combined with frost
resistance of seed parent. Appears to be weakly fertile. Twenty-eight trees.
(P. attenuata X P. radiata) X self. (F2) hybridity certain. Progeny 3 years
old. Five trees.
P. cariba-ca (slash pine X P. taeda (loblolly pine). Hybridity probable. Prog-
eny 3 years old. Ten trees.
P. echinata (shortleaf pine) X P. taeda. Hybridity probable. Vigor of
2-year-old progeny exceeds that of seed parent. Fourteen trees. Seedlings
now 3 years old.
P. ponderosa var. jeffreiji X P. ponderosa. Hybridity certain. Vigor of
3-year-old progeny greatly exceeds that of seed parent. A potentially valuable
cross.
P. rigida (pitch pine) X P. taeda. Hybridity probable. Four trees. Age
3 years.
The following artificial crosses were made with various species and varieties
of Juglans in 1927:
./. hindsii X Royal hybrid; 12 hybrid seedlings obtained.
Royal hybrid X Royal hybrid; 7 hybrid seedlings obtained.
Royal hybrid X J. mandshurica; 1 hybrid seedling obtained.
Royal hybrid X J. regia; 3 hybrid seedlings obtained.
/. hindsii X J. hindsii; 3 seedlings obtained.
Royal hybrid X J. hindsii; 1 h3"brid seedling obtained.
Central States Forest Experiment Station 9
1. Seed Origin
Robinia pseud oa-cacia (black locust)
Experimental work was started in 1935 with approximately 22 strains of black
locust, including the shipmast locust (var. rectissima), in a search for strains
resistant to locust borer.
Yellow pines
Work of a minor nature is in progress with local strains of shortleaf, pitch, and
Virginia pines.
Intermountain Forest and Range Experiment Station 10
1. Seed Origin
Pinus ponderosa (ponderosa pine)
Some experimental work on importance of seed origin is being carried on but
work is too recent for definite observations.
Future plans call for investigations on regional and altitudinal strains of this
species.
•At Columbus, Ohio.
io At Ogden, Utah.
1270 YEARBOOK, 1937
Lake States Forest Experiment Station n
1. Seed Origin
Pinus resinosa (Norway pine)
Three plantations each containing progeny from 154 seed sources (Lake States,
Pennsylvania, New York, New England, Quebec, Ontario) were established in
1931 and 1933. Seed collection was mostly from "individual tree" or "small
group" but some "limited locality" and general collections are also represented.
Differences are already apparent in vigor, winter hardiness, and drought resistance.
Pinus sylveslris (Scotch pine)
Progeny from 27 seed sources (United States and foreign) were included in the
plantations of Norway pine (1931 and 1933). Differences have been observed
in the nursery and in the field between northern and southern stocks in size of
seedlings and color of foliage — stock from southern sources is larger and tends to
have darker green foliage Northern stocks showed markedly superior winter
resistance, 1935-36.
Picea (spruce)
In a search for fast-growing spruce for pulpwood, plantations of nine different
spruces were established in 1936. The following species were used: P. glauca
(white spruce) six seed sources; P. excelsa (Norway spruce) six sources, mostly
from the Union of Soviet Socialist Republics; P. rubra (red spruce) two sources;
P. glauca alberiiana (Alberta spruce) ; P. mariana (black spruce) ; P. glehnii
(Sakhalin spruce); P. orientalis (Oriental spruce) ; and P. omorika (Serbian spruce)
Seed of the last five each from one source.
2. Individual Seed-Tbee Progeny Tests
Fraxinus pennsylvanica lanceolata (green ash)
Progenies of 83 individual trees (from North Dakota, South Dakota, Iowa,
Nebraska, Kansas, and Oklahoma) were grown in two nurseries (York, Nebr.,
and Denbigh, N. Dak.). Variations between individual progenies were apparent
in the nursery; seed from the northern area exhibited slow germination and
growth. Seedlings from northern stock were much smaller, with smaller, darker
green leaves, an d shorter growing periods than southern stock. Transplants of the
York stock were field-planted in Nebraska in the fall of 1936, but are insufficient
in number to give conclusive results.
Artificial drought tests indicated a definite decrease in drought resistance from
north to south and from west to east (definitely correlated with climate). The
greatest difference was observed between plants from the northwest portion of
North Dakota and the eastern portion of Nebraska, Kansas, and Oklahoma.
The evidence indicates that there are inherently different climatic races. Local
variations within a single subdivision of the plains region were also observed.
Pinus resinosa (Norway pine)
Approximately 100 of the 150 seed lots mentioned under Seed origin were from
individual seed trees. A few of the individual progenies are sufficiently out-
standing to indicate that selection and breeding might produce a superrace of
Norway pine.
Pinus sylvestris (Scotch pine)
Some 20 of the 27 seed lots obtained for provenience study were from individual
seed trees growing in the Lake States. No significant differences have been
observed to date.
Northeastern Forest Experiment Station 12
1. Seed Origin
Pinus sylvestris (Scotch pine)
Two-year-old seedlings of two strains of Scotch pine, Riga and Austrian, were
outplanted in 1925 on the Mount Toby Demonstration Forest in Massachusetts.
After 11 years the Austrian Scotch pine has made 2 to 3 feet better height growth
» At St. Paul, Minn.
12 At New Haven, Conn.
FOREST TREES
1271
and greater diameter growth than the Riga strain, and it appears to have a superior
stem form.
Studies are under way to determine whether a single vigorous stock of Scotch
pine is suitable for planting in all parts of the Northeastern region. In 1932, 2-2
planting stock from a single seed source (Booneville, N. Y.) was planted in 10 test
plots of 1,200 trees each throughout the Northeastern States. Additional plant-
ings were made in 1934 using 1-2 and 2-0 stock from the same source. No signifi-
cant results have been noted up to the present time.
A rather comprehensive forest-genetics project is now being started. It is
anticipated that this project will include practical and fundamental research on
seed origin, adequate progeny tests, selective breeding and hybridization. Al-
though the primary emphasis will probably be placed on deciduous forest trees,
some work with conifers, particularly with reference to disease and insect resistance
of native species, will undoubtedly be advisable. The station also expects to
cooperate with the Oxford Paper Co. in continuing the valuable hybridization
work with poplars started by that organization in 1924.
Northern Rocky Mountain Forest and Range Experiment Station 13
1. Seed Origin
Pinus ponderosa (ponderosa pine)
Twenty-two experimental plots in northern Idaho contain progenies from
seed collected in 22 geographic localities in Oregon, California, Idaho, Washing-
ton, Montana, South Dakota, Colorado, Arizona, New Mexico, and Utah. The
trees are now 23 to 27 vears old from seed.
Figure 13. — Racial differences in ponderosa pine: A, The open, piumelike arrange-
ment of long, slender needles of the North Pacific and Northern Rocky Mountain
races is easily distinguished from II. the compact and hushlike growth of short, stout
needles of races from the east slope of the Rocky Mountains,
"At Missoula, Mont.
1272
YEARBOOK, 1937
A number of distinct races have developed under natural conditions in ponder-
osa pine, which is widely distributed throughout the Western States and is sub-
ject to a great diversity of environmental conditions (fig. 13). Progenies from
sources west of the Continental Divide in the North-Pacific and Northern Rocky
Mountain regions have long, slender, flexible needles with slight to moderate
thickening of the hypoderm cell walls, prevailingly in three-needle fascicles (fig. 14,
A). Trees from east of the Continental Divide and in Colorado and Utah have
foliage prevailingly in two-needle fascicles with short, thick, stiff needles with
extremely thick hypoderm tissues (fig. 14, B). Trees from the Arizona-New
^4
Figure 14. — Races of ponderosa pine show inherent differences in needle structure:
I . An example of the thin hypoderm layer and lack of stomatal depressions of the
long-needle type shown in figure 13, A; B, thicker hypoderm layer without stomatal
depressions, characteristic of the short-needle type illustrated in figure 13, B.
Mexico Plateau have preponderantly three-needle fascicles, with moderate
length and slenderness of needles, but with thick hypoderm structure. As these
pronounced differences in foliage were found to be the same in trees of the parent
localities, the conclusion is that these characteristics are strongly heritable.
Progenies that originated in localities within the northern Rocky Mountains,
where the climate was similar to that of the experimental site, have made the
greatest growth in height and diameter. Those from regions of more severe
climates in Colorado, Utah, Arizona, and New Mexico have made the least. The
slowest growing progenies in the experiment have reached an average height
and diameter only half that of the fastest growing offspring. Comparison of
progenies with trees growing in parent localities shows strong inheritance of growth
rate in the new environment, except that the tendency is less marked where the
progeny came from a region of more favorable climate.
Relative degree of hardiness was revealed by a sudden steep drop in tempera-
ture of 57° F. on December 15, 1924. Two progenies from the mild Pacific
coast region were practically eliminated. The progenies from regions of the most
rigorous winter climates suffered little or no loss by this freeze.
FOREST TREES 1273
The results to date indicate that the most suitable seed source for planting
in northern Idaho is from Republic, Wash., to the Continental Divide and from
the Salmon River to the Canadian boundary. Introductions from the mild
climate of the Pacific coast are subject to loss from sudden and severe tempera-
ture changes, which may occur periodically in Idaho. Although an introduced
tree may be perfectly adaptable to the climate, it may, because of slow growth,
be decidedly unsuitable for timber growing in northern Idaho. On this basis
seed from Black Hills and southeastern Montana sources would be unsatisfactory,
and Colorado seed would prove decidedly so.
Pacific Northwest Forest Experiment Station u
1. Seed Obigin Pseudotsuga laxifolia (Douglas fir)
Five replicative plantations were established in 1915 with seed from 13 locali-
ties (northwestern Washington to central-western Oregon, 100- to 3,850-foot ele-
vations) to study climatic and geographic races within the Pacific coast form.
Progenies from individual trees representing variations in age, form, infection
by wood-rot fungi, and site conditions were planted under separate pedigree
numbers. No gross differences have been observed in morphological character-
istics (leaves, crown, stem, flowers) between progenies from different seed sources.
A significant and constant difference was observed in the relative time at which
the various progenies burst their buds in the spring. Different progenies also
varied in their susceptibility to late-spring frost injury. The progenies of certain
individual parents were significantly taller than those from other parents growing
in the same locality. The progeny from two of the seed-source localities made out-
standingly good height growth on every plantation.
Pinus ponderosa (ponderosa pine)
Plantations were established in 1926 for a study of geographical races of this
species. Results indicate that local stock is doing best in growth and survival.
Progenies from different seed sources are already beginning to show rather dis-
tinct variations in the appearance of the foliage.
Rocky Mountain Forest and Range Experiment Station 15
1. Seed Origin pinm pon^erosa (ponderosa pine)
Test plantations were established at Fremont in 1915 and 1916 with seed from
seven sources (five Colorado, one Wyoming, and one South Dakota). Altitude
range of seed sources was from 5,200 to 9,000 feet. A second test plantation was
established in 1920 with seed from eight sources (one each from Montana, Arizona,
California, Oregon, South Dakota, and three from Colorado) . Data are available
on survival, height, and form. The results from the standpoint of survival, rate
of growth, and winter-hardiness point conclusively to the futility of using any but
Colorado (not including southwestern pine type) and possibly Black Hills seed.
Test plantations were established in the Nebraska National Forest (1926) with
seed from eight sources (Nebraska, South Dakota, Colorado, Arizona, New
Mexico). The results indicate the superiority of local Nebraska seed. South-
western and central Rocky Mountain stocks have been extremely susceptible to
tip-moth attack. A segregated seed area has been established.
Pinus contorta (lodgepole pine)
A plantation at Fremont now 21 years old includes trees from seed collected
from nine localities in Wyoming and 'Colorado. There is also a 17-year-old plan-
tation, established with stock from 14 sources from approximately the same general
region. In general the nearest seed sources have given the best results, but the
extent of variation within a seed progeny largely eliminates the significance of the
group performance.
A test planting in the Medicine Bow Forest, Wyo., is now 17 years old; seed
from three sources (local, southern Wyoming, western Colorado). The relative
survival and performance have been in inverse ratio to proximity of the seed source
to the experimental area.
» At Portland, Greg.
»At Tort Collins, Colo.
138904°— 37 81 + +
1274 YEARBOOK, 1937
Pseudotsuga taxifolia (Douglas fir)
A 20-ycar-old plantation at Fremont includes stock from 11 national forests (6
in Colorado, 5 in Wyoming) and 15 climatic sources. Last observations (1923)
indicate that local stock is decidedly superior in survival and height growth.
Wyoming stock failed completely.
Picea engelmanni (Engelmann spruce)
A plantation on the east slope of Pike's Peak (elevation 10,500 feet), 24 years
old, contains 10 climatic strains from 6 Colorado National Forest seed sources.
Results are not conclusive.
2. Individual ^bed-Tuf.e Progeny Tests.
Pinus ponderosa (ponderosa pine)
Test plots were established in 1932 at elevations of 7,200 feet and 9,100 feet in
the Pike's Peak locality with progeny from eight individual parent trees represent-
ing a 2,000-foot altitudinal range within the same locality. The lower plantation
was eliminated by drought. 1 n the upper plantation survival shows a fairly regular
increase from low to high elevation sources.
Progeny from individual mistletoe-susceptible and presumably mistletoe-
resistant trees are being tested in two 4-year-old plantations at Fremont station.
Three plantations (3, 4, and 6 years old) in the Nebraska sand hills include
progeny of individual trees selected because of superior development a~nd freedom
from Peridermium.
Pseudoisuga taxifolia (Douglas fir)
Progeny of individual parent trees possessing peculiar branching habits are
under observation in two plantations at Freemont (6 and 8 years old) .
3. Tree Breeding
Artificial crosses between individuals of an apparently mistletoe-immune strain
of Pinus -ponderosa (ponderosa pine) have been successful. Seedlings are now 4
years old.
Southern Forest Experiment Station 16
1. Seed Origin*
Pinus taeda (loblolly pine)
Test plots were established hi 1927 at Bogalusa, La., with trees from seed col-
lected in Louisiana, Texas, Arkansas, and Georgia. Observation in the spring of
1936 (trees 9 years in field) showed local Louisiana seed definitely superior in
growth rate. Other significant differences may exist.
Pinus palustris (longleaf pine), P. caribaea (slash pine), P. taeda (loblolly pine),
P. echinata (shortleaf pine)
Test plantations were started on the Palustris Experimental Forest (1935-36)
with stock from seed of various geographic sources. The following species were
used: P. pahtstris (eight sources) , P. caribaea (nine sources), P. taeda (two sources) ,
P. echinata (two sources) .
Seed of the following four species was obtained from 40 different sources in 1935:
P. palustris (11 sources), /'. caribaea (7 sources), P. taeda (12 sources). P. echinata
(10 sources). Seedlings from seed of practically all sources for each species were
grown at or near each point of origin, for planting during the 1936-37 planting
season. The purpose of this is to test every geographic strain both in its own
locality and in every other locality included in the study of that species. In at
least one nursery distinct differences in size and in rate of maturing were apparent
in the fall of 1936, the most conspicuous being between shortleaf pine seedlings
from Pennsylvania and from Texas seed.
2. Individual Seed-Tree Progeny Tests
Pinus palustris (longleaf pine)
A test plantation was started in 1936 with 300 seedlings from parents high in
naval stores yield and from parents low in yield.
i" At New Orleans, Lu.
FOREST TREES 1275
3. Tree Breeding
Pinus palustris x P. caribaea, hybridized in 1929, produced approximately 24
hybrid seedlings intermediate between the parents in stem, foliage, and bud char-
acteristics, growth habit, and rate of growth. X P. sondereggeri (Fi) was crossed with
P. palustris, P. iaeda, and X P. sondereggeri. A few seedlings were obtained from
each of these crosses and were planted out in 1933.
Southwestern Forest and' Range Experiment Station u
1. Seed Origin
Pinus ponderosa (ponderosa pine)
Tests of climatic races are under way at the Fort Valley station. Results
indicate that seed from California and the northwest portions of the United States
invariably germinate less rapidly and produce larger, more succulent, but notice-
ably less hardy seedlings than local seed. Seed from Colorado, Utah, and Black
Hills produce plants much like those from local seed, but Black Hills seedlings
always show characteristic differences in color and form, and 20 years after
planting are beginning to show signs of decline.
Tennessee Valley Authority, Forestry Division 18
2. Individual Tree Selection
The tree crop unit of the Forestry Division has been interested in the selection
of individual forest trees that combine desirable timber quality with production
of high quality and quantity of fruit (nuts, acorns, berries). This work has been
carried on through prize contests and through direct scouting. Up to the present
time, one black walnut, two black locusts, two honey locusts, one ash, one hickory,
and two oaks have been discovered which appear to merit special study. These
individuals are being multiplied vegetatively by grafting and budding.
3. Tree Breeding
The tree crop unit initiated a project in hybridization and breeding in the
spring of 1936. During this first year, a total of approximately 5,000 artificial
pollinations were made with 72 species, varieties, and clones of the following 10
genera: Juglans (walnut), Hicoria, syn. Carya (hickory), Corylus (hazel), Castanea
(chestnut), Quercus (oak), Asimina (pawpaw), Amelanchier (scrviceberry),
Gleditsia (honeylocust) , Robinia (black locust), and Diospyros (persimmon).
The purpose of this breeding work was to produce trees combining high pro-
ductivity and high quality of fruit (nuts, berries, acorns, pods) with desirable
timber qualities. Such superior trees are needed for tree-crop planting and will,
before maturity of the timber crop, pay their way by the annual production of
food for man, stock, or game.
The severe spring drought in eastern Tennessee resulted in the loss of a con-
siderable portion of seed that had originally set to cross-pollination.
United States — State, Private, and Endowed Agencies
Brooklyn Botanic Garden n
3. Tree Breeding
Controlled breeding experiments were undertaken in 1930, to produce a chest-
nut with inherently good timber form and high resistance to or immunity from the
chestnut blight disease. The work was started with Japanese and American
chestnuts, but in recent years additional species, varieties, and hybrids have been
used as parent stocks. Some of these hybrids are now 5 years old. Up to the
present time, the following Castanea hybrids have been produced ((E) indicates
reciprocal crosses between the parents) :
C. crenata (Japanese c.) X C. dentata (American c.)
C. mollissima (Chinese c.) X C. denlata (R)
C. S8 X C. dentata (R)
C. S8 X C. crenata (R)
C. crenata X (C. crenata X C. dentata) (R)
17 At Tucson, Ariz.
i« At Norris, Term.
i» At Brooklyn, N. Y.
1276 YEARBOOK, 1937
(C. crenata X C. deniata) X C. mollissima (R)
(C. mollissima X C. pumila (chinquapin) X C. deniata
C. crenata X C. seguinii (Chinese chinquapin)
C. mollissima X 0. seguinii
(C. crenata X C. deniata) X C. dentata
(C. crenata- X C. dentata) X (C. crenata X C. deniata)
(Note.— S8 is apparently a combination o/ C. crenata and C pumila; made by "Walter Van Fleet, IT
S. Department of Agriculture.)
Many of the C. crenata X C. dentata hybrids give promise of timber types and
appear to be resistant to chestnut blight. So far, they have been subjected only
to natural infection, but in 1936 all hybrids were artificially inoculated. It is too
early to determine the results of these inoculation tests. Some of the hybrids
bloomed at 3 years of age; these were immediately used for further hybridization.
1. Seed Origin- Fox Research Forest 20
Investigations originally started by the Brown Co. are being conducted with
Scotch pine, Norway spruce, and European larch. The purpose of these experi-
mental plantations is to determine the most desirable proveniences for reforesta-
tion in New Hampshire. Most of the plantations are too young to provide per-
tinent information.
New York Stale Conserration Department, Bureau of Investigation 21
1. Seed Origin
Pinus si/lvestris (Scotch pine)
Four generations, ranging in age up to 30 years, are now available for study.
Observations to date indicate the possibility of rust-resistant strains and two
apparently inherent growth forms; a straight-boiled, small-limbed type with
small pointed crown, and a fairly straight-boled, large-limbed type with large
bushy crown.
New York State College of Forestry 22
2. Seed Origin
Investigations with climatic varieties of two species of Picea, five species of
Pinus, and two species of Larix have been started on the Pack Demonstration
Forest, Warrensburg, N. Y.
Oxford Paper Co. in Cooperation with the New York Botanical Garden 23
3. Tree Breeding
A breeding project was initiated in the spring of 1924 to develop new hybrid
poplars of particular value for pulpwood reforestation in Maine (Stout and Schrein-
er, 1933) .24 A total of approximately 13,000 hybrid seedlings was obtained from
99 different cross combinations between 34 different types of Po-pulus, as follows:
The parents are arranged in alphabetical order within the main groups of
poplars, and the extent to which each was used in hybridization is indicated by
the use of the numbers assigned in the sequence. The number of seedlings grown
for each cross is indicated iti italics under the female parent. Thus in the cross
P. albaXP. alba nivea 67 seedlings were grown.
A. The white poplars.
1. Populus alba ? X2 (67); 3 (8) ; 4 (34); 0 (22); 7 (16).
2. P. alba nivea cT X I.
3. P. canescens d1 X 1 .
B. The aspens.
4. P. adenopoda&X.l, 17.
5. P. grandidentata c? X10, 31, 32.
6. P. tremula <? XI, 8.
7. P. tremnla Dauidianad'Xl.
8. P. lremuloides<i X6 (11).
*« At Hlllsboro, N. 11.
!' At Albany, N. Y.
21 At Syracuse, N. Y.
'■' At Kumford, Maine, and Bronx Part, New York City, respectively.
81 See Bibliography, published in the Yearbook separate of this article.
FOREST TREES 1277
C. The black poplars and cottonwoods.
9. P. angulala? X 10 (688); 11 (248); 12 (99); 16 (SOS); 21 (214); 22 (00):
25 (214)} 26 (005); 34 (004).
10. P. balsamifera virginiana? X5 (17S); 10 (1SS); ii (IS); 12 (189);
16 (005) ; 21 (188) ; 22 (7) ; 25 (010) ; 26 (245) ; 34 (705) . d" X 9, 10,
13, 15, 18, 19, 23, 31, 33.
11. Cottonwood (unidentified) 0^X9, 10, 13, 15, 18, 19, 31.
12. P. caudina<?X9, 10, 13, 18, 26, 29, 30, 31, 32.
13. P. charkomensis 9 X10 (288); 11 (267); 12 (266); 16 (268); 21 (310);
22 (52); 25 (188); 26 (249); 34 (221).
14. P. Eugenei clone o*X 17, 23.
15. P.fremontil X10 (7); 11 (3); 16 (108); 21 (J&j); 25 (017); 26 (69);
34 (105).
16. P. wcrassataa1X9, 10, 13, 15, 18, 19, 29, 31, 32.
17. P. mora? X 17 (0); 14 (49); 17 (1«4); 20 (44); 27 (217); 28 (377);
32 (0); 34 (000).
18. P. w'jra baatanicorum vitrum^ X10 (0); 11 (00): 12 (51); 16 (10):
21 (157); 25 (170); 34 (101).
19. P. mora betulifolia? X 10 (11); 11 (11); 16 (141); 21 (05); 25 (100);
34 (209).
20. P. ttiora Italica (clon Lombardy) o"X17, 23.
21. P. mora pta««iemm"sd,X9, 10, 13, 15, 18, 19, 26, 29, 31, 32, 33.
22. P. robusta clone o" X9, 10, 13, 32.
23. P. sargenlii? X10 (70); 14 (50); 20 (05); 23 (35); 26 (140); 27 (809);
28 (51); 32 (14); 34 (288).
24. P. serotina clone d1 X 26.
25. P. wfaa eloneo"X9, 10, 13, 15, 18, 19, 26, 31, 32.
D. The balsam poplars, and the older hybrids strongly balsam in character.
26. P. barolinensis1} X12 (8); 21 (17); 24 (00); 25 ( 00); 26 (31); 34 (07).
tf1 X 9, 10, 13, 15, 26, 23, 29, 31, 32, 33.
27. P. berolinensis rossica d"X 17, 23.
28. P. laurifoliad'X 17, 23, 33.
29. P. maximowicziil X12 (170); 16 (0); 21 (145); 00 (110); 34 (5).
30. P. petromskyana 9X12 (05) .
31. P. rasumowskyana9 X5 (0); 10 (50); 11 (.50); 12 (70); 16 (05); 21 (70)
25 (81); 26 (153); 34 (148).
32. P. simonn9X5 (32); 12 (00); 16 (75) 21 (176); 22 (1); 25 (155)
26 (189); 34 (44). cfX17, 23.
33. I3, taeamahacca candicans clone Balm of Gilead 9 X10 (0); 21 (40)
26 (80); 28 (0).
34. P. *rc'cftoca;-pad,X9, 10, 13, 15, 17, 18, 19, 23, 26, 29, 31, 32.
Approximately 700 hybrid seedlings were originally selected for intensive study
and evaluation, and of this number 69 are still under close observation. Descrip-
tions have been published of 10 of these hybrids that appear particularly promising
for use in reforestation.
Propagation of the new poplar hybrids has been entirely vegetative, by cuttings.
Many of the hybrids have so far indicated greater growth vigor than any previously
known poplar species or hybrids. Some have been practically immune to certain
diseases, particularly Melampsora rust and Fusicladium twig disease. Selections
have included frost-hardy types with good forest form that grow vigorously from
cuttings. There is evidence that the wood of many of the fast-growing hybrids
will be denser, and will produce somewhat longer fibers, than the aspens now
used for pulpwood. Most of the original hybrids are growing in plantations
(now 9 and 10 years old) and many have begun to bloom; some individuals
flowered at the age of 7 years.
Foreign Agencies
Austria, Forstliche Bundes, Versuchsanstalt, Mariabrunn
1. Seed Obi gin
Considerable research has been carried out on climatic races and on the im-
portance of the seed origin of forest trees. This work was started previous to
1900. The progress of the work has been reported in publications by Cieslar,
Tschennak, and Oehm.
1278 YEARBOOK, 1937
Canada, Petaivaiva Forest Experiment Station,25 Ontario
3. Tbeb Breeding
Crosses between black spruce and Norway spruce, attempted in Canada in
1934, were unsuccessful. In 1936 Populus canescens was crossed with P. grandi-
dentata, and P. tremuloides was crossed with P. grandidentata, in an effort to
obtain a hybrid combining the wood characteristics required for match and
veneer wood with resistance to heart rot.
C. Hoimburger of this station reports that in 1932 he crossed red spruce witli
Norway spruce while working in New York State. Good seed was produced,
and the seedlings are now being grown by the New York State College of Forestry.
Denmark, Royal Veterinary and Agricultural College, Copenhagen
3. Tree Breeding
In the spring of 1924, Abies concolor lowiana (Pacific white fir) was successfully
crossed with A. grandis (lowland white fir), and the hybrids are under observa-
tion at the present time. In 1929 Juglans sieboldiana (Japanese walnut) was
successfully crossed with J. cinerea (butternut) . Reciprocal crosses have been
made between Larix leptolepis (Japanese larch) and L. decidua (European larch).
Rather extensive self-pollinations have been made by covering portions of large
trees, or entire smaller trees, with closely woven canvas. A tree of Chamaecyparis
sp. was sclfed by covering its top. A larch (7.1 m tall) thought to be a hybrid
between Larix gmelini and L. leptolepis was tented and self-fertilized. A small
Japanese larch was also selfed by potting and transferring it to a greenhouse.
Germany, Botanisches Institut der Forstlichen Hochschule, Eberswalde
1. Seed Origin
Studies arc now under way on climatic races of Pinus sylvestris (Scotch pine)
and Pseudotsuga taxifolia (Douglas fir). Progenies of Douglas fir from 19 differ-
ent seed sources are growing in the vicinity of Eberswalde. Particular emphasis
has been placed upon the possible selection of Douglas fir races that are highlv
resistant to Rhabdocline leaf disease. Results to date indicate that in general the
American coastal forms, although not entirely immune, are sufficiently resistant
to warrant further use in forest planting; that the mountain forms are slower
growing, more susceptible to the disease, and cannot be recommended; and that
certain types should be discontinued entirely.
3. Tree Breeding
Reciprocal crosses between Pinus montana and P. sylvestris have apparently
been unsuccessful. Since natural hybrids between these species have been
reported, it is possible that the negative results may have been due to lack of
"crossibility" of the strains that were used.
Germany, Forstbotanisches Institut, Technischen Hochschule, Dresden
(Forstliche Abteilung Tharandt)
1. Seed Origin
Seed origin investigations of a large number of forest trees, including pine,
spruce, larch, oak, beech, aspen, alder, ash, and maple, are under way at this
station. In addition to the above the following species of most diverse seed
origin are also being tested in experimental plots: Pseudotsuga taxifolia, Betula
verrucosa, Pinus murrayana, Abies cilicica, Pinus armeniaca, P. peuce, Picea
engelmannii, P. sitchensis, Chamaecyparis lawsoniana.
Great Britain, Forestry Commission of Great Britain, Research Division 26
1. Seed Oricin
Investigations on climatic races of Pseudotsuga taxifolia, two species each of
Larix, Picea, and Quercus, and four species of Pinus are under way. This work
was started in 1925 and it is too early to draw any conclusions. The investiga-
tions will include a study of growth and form, frost-hardiness, and resistance to
fungus and insect attacks.
25 At Petawawa, Ontario.
"At London.
FOREST TREES 1279
Switzerland, Eidgenossische Zentralanstalt fiir das Forstliche
Versuchswesen, Zurich
1. Seed Origin
Studies on site races,f orm races, and so forth, were started in 1898 with two species
each of Pinus and Quercus, one species each of Picea, Abies, Larix, Fagus, Acer, and
other important tree species. These studies include the influence of geographical
location, latitude, altitude, soil, precipitation, form, age, and position of the
parent tree in the stand. Results indicate that the following characteristics are
inherited: Color and size of needles and leaves, crown form, stem form, increment,
growth periods, and resistance to frost, heat, light, snow, fungi, and insects.
These investigations are of great importance since they are to bo applied to
protection forests in many of the regions where natural regeneration is practiced.
Results have been published by Engler, Nageli, and Burger.
BIBLIOGRAPHY
A bibliography for this article, including over 300 references related to forest
tree breeding, will be published in the 1937 Yearbook Separate containing the
text of the article.
BREEDING PROBLEMS
WITH ANGORA GOATS
W. V. LAMBERT, Senior Animal
Husbandman, Animal Husbandry Di-
vision, Bureau of Animal Industry
i^INCE its domestication the goat has served man well. As a source
of milk, meat, mohair, and skins it has furnished him both food and
clothing, and because of its brush-eating proclivities, has spared him
untold amounts of hard labor with the brush hook.
Since 1900 the Angora goat industry in the United States has under-
gone rapid expansion. At present it is confined largely to the South-
western States, nearly 90 percent of all Angoras being produced in
Texas, New Mexico, and Arizona. The estimated average yield of
mohair per goat in 1935 was 4.4 pounds although the average yield
in some of the better flocks was probably twice as great. Practically
all improvement has come about through practical breeding. In
comparison with other farm animals, little in the way of scientific
research has been done with the Angora goat. The Texas Agricultural
Experiment Station is the only place in the United States where experi-
mental work is now known to be conducted with this breed. Re-
search is badly needed on problems pertaining to the development of
strains yielding larger amounts and a better quality of mohair. Tech-
niques have been developed for the study of mohair that, combined
with the proper genetic research, offer possiblities of improvement
yet unrealized.
It is quite certain that the goat was one of the first domestic animals.
In all probability, it was first domesticated in western Asia, and from
there it was brought into Africa and other countries. After centuries of
selection, the domestic goat is very different from its wild ancestor.
The goat is probably descended from the pasang or Grecian ibex
(Capra hircus aegagrus), a species of wild goat found in Asia Minor,
Persia, and contiguous countries. It appears unlikely that any wild
species other than the pasang had an appreciable part in the ancestry
of the domesticated goat, although for some breeds, as the Malayan,
Cashmere, and Angora goats, the evidence is not so convincing that
this form was the sole ancestor. It is possible that the ibex and markhor
may have been represented in the ancestry of these breeds, for Lydek-
ker (9)1 states that both of these forms will breed readily in confine-
ment with domesticated goats.
The development of the long-haired type of goats was accomplished
centuries ago, principally in Asia Minor, where the Province of
Angora gave its name to the best known of such breeds. How the
short hair of the pasang and other possible ancestral forms developed
1 Italic numbers in parentheses refer to the Bibliography p. 1292.
1280
ANGORA GOATS 1281
into the long hair characteristic of the Angora goat is not clear, but
it seems most likely that it was simply by the selection of animals with
variations in length of hair. Whether a single major mutation ac-
counted for the change, as appears probable for long-haired types in
the rabbit and the guinea pig, is unknown, but it would seem certain
that the selection of minor variations in length of hair has modified
the character in the desired direction.
According to Willingmyre, Window, Spencer, and others (W),
the original Angora goat was described as a comparatively small animal
with a fine lustrous, silky fleece that hung in ringlets and attained a
length of 8 to 10 inches. In the early part of the nineteenth century
the demand for raw mohair became so great that the Turks, who were
the original breeders of the Angora, were unable to increase their herds
rapidly enough to meet the demand. This resulted in hybridization
of Angora bucks with common Kurd does in an effort to increase the
number of mohair-producing animals quickly by grading up the com-
mon goats of the region. This practice became so prevalent that
purebred Angora goats were practically eliminated. However, the
new type of Angora developed from these cross-breds is a larger and
hardier animal that yields a heavier though somewhat coarser fleece
than the original Angora.
THE DISTRIBUTION OF ANGORA GOATS
FROM ASIA MINOR
Although the Angora goat was developed in Asia Minor centuries
ago,2 its spread into other portions of the world is relatively quite
recent. The first European record of the Angora goat appears in 1554
when, according to Cronwright Schreiner (2), the Dutch ambassador
at Constantinople procured a pair of Angoras and sent them to the
Emperor, Charles V. However, mohair yarn was known before this
date in Europe. Following this early importation of Angora goats
'The uso of mohair can be traced to the time of Moses. Tbo Bible records that Moses commanded the
children of Israel, after being delivered from slavery in Egypt, to bring white silk and goats' wool to weave
altar cloths for the tabernacle (SO).
ONE of the most urgent needs for breed improvement in all branches
of livestock, including mohair goats, is the development of more and
better criteria for the selection of breeding animals. Too generally,
selection is based solely upon the animaVs appearance, or pheno-
type, and it is a well-known fact, substantiated both by practical
experience and by genetic evidence, that appearance is not always a
good criterion of an animal's breeding worth. It is of value and
must be taken into account, but it is only a part of the story. The
question is, not what an animal looks like, but what inheritance it
will pass on; and it is impossible to determine this from appearance.
1282 YEARBOOK. 1937
to Europe, many attempts were made to establish tliem but without
success until the nineteenth century.
In 1838 Angora goafys were first introduced into South Africa. These
goats were crossed with native goats and by a process of selection and
inbreeding, herds of high merit were established. The goats were
prized by the Boers, not so much for their mohair, but, according to
Eose {12), because the infusion of the Angora blood into the native
herds made the cross-bred goats less subject to cutaneous diseases and
more able to resist scab. The cross-breds were also earlier maturing
and heavier than the native goats, and their flesh was more palatable.
No more importations were made into South Africa until 1856, but
after that date several were made and the industry has grown until
today South Africa, Turkey, and the United States are the countries
producing the largest quantities of mohair.
The first importation of Angoras into the United States was made
in 1849 by James C. Davis of Columbia, S. C. It consisted of nine
choice animals — seven does and two bucks. These goats were ex-
hibited at many fairs, where they won numerous prizes and received
much publicity, with the result that great interest was stimulated in
Angora goats.
In 1860 a second importation of 8 Angoras was made by William
Henry Stiles of Carters ville, Ga., this being followed by an importa-
tion of 67 goats by Winthrop W. Chenery of Belmont, Mass., in 1861.
In the next decade several importations were made, including one
by Israel S. Diehl, who had been commissioned by the United States
Commissioner of Agriculture in 1867 to visit the Province of Angora
for the purpose of investigating the mohair industry.
During the 30 years from 1870 to 1900 several small importations
were made by various breeders, mostly bucks to be used in the im-
porters' herds. In 1904 one of the largest and most notable of all im-
portations, consisting of 148 goats, was made by G. A. Hoerle of Mid-
land Park, N. J. This shipment, which came from South Africa,
was made possible by the temporary suspension during the Boer War
of the very high export duty of 100 pounds sterling on each Angora
goat by the South African Government. Soon thereafter the expor-
tation of Angora goats was prohibited from South Africa and this
embargo remained in effect for nearly 20 years.
Recent importations of Angora goats have been few and limited to
a small number of individuals, mostly bucks. The latest importation
from South Africa was made by E. Cawood into Texas in 1925.
THE ANGORA GOAT INDUSTRY IN THE UNITED STATES
Following the Civil War the growing of Angora goats spread into
many parts of the country and the number of goats increased rapidly.
Introduction into new regions was at first largely for the purpose of
brush extermination on new lands being opened for settlement in the
West. In some regions where these goats proved to be well adapted,
however, an interest in Angoras for the production of mohair devel-
oped, and the industry has finally become firmly established in certain
sections.
Since 1900 the industry in the United States has undergone rapid
expansion. The number of Angora goats increased from 329,300 in
ANGORA GOATS
1283
1900 (1) to 2,101,591 in 1920 and to 3,785,127 in 1930 (14). Figures
showing the status of the Angora goat industry in the United States
in 1930 are given in table 1.
Table 1. — The status of the Angora goat industry in the United States in 1930
Region
Total
Angora
goals
Angora
goats by
regions
Total
farms in
the United
States
Farms reporting
Angora goats
Average
per farm
reporting
Number
2, 956, 584
193, 639
193, 320
119, 341
78,839
45, 286
198, 118
Percent
78.1
5.1
5.1
3.2
2.1
1.2
5.2
Number
495, 489
31,404
14, 173
55, 153
255, 940
135, 676
5, 300, 813
Number
9,287
1,177
590
2,895
3,454
1,025
15,951
Percent
1.9
3.7
4.2
5.2
1.3
.8
.3
Number
318.4
164.5
327.7
41.2
22.8
44.2
All other States
12.4
3, 785, 127
100.0
6, 288, 648
34, 379
.5
110.1
From these figures it is apparent that Angora goat production is
largely confined to the southwestern part of the United States; and
that Texas had over 78 percent of all Angora goats in 1930, with
New Mexico and Arizona accounting for over 10 percent of the remain-
ing goats. In Texas the majority of the goats are raised in the Edwards
Plateau area in the southwestern part of the State, where they are kept
in large numbers on ranches. In Arizona and New Mexico similar
conditions exist, this method of production being responsible for the
large number of goats reported per farm in those States.
Since 1930 there has been some decline in the total number of
Angora goats in common with a reduction in number for most classes
of livestock. The 1935 census of agriculture listed 4,093,441 goats
of all kinds in the United States, whereas in 1930 a total of 4,821,294
were listed. If there was a proportionate reduction in the number of
milk and Angora goats the approximate number of Angora goats in
the United States in 1935 was 3,211,000.
The production of mohair and estimated average weight of mohair
fleeces at 5-year intervals since 1920 for the six leading States are
shown in table 2. While the total production of mohair increased in
proportion with the increase in number of goats, it may be noted
that the average production per goat did not increase greatly, although
there was a slight, but not constant, increase in average fleece weight.
For some States, notably Texas, New Mexico, and Oregon, the
average weight of fleece was greater than for other States. The
reason for this is not apparent, but it is probable that both better
breeding and better management were responsible. For instance,
Angora goats in Missouri are kept in small herds principally for the
purpose of clearing brushland, whereas in Texas and some of the
other States they are kept in large herds primarily for the production
of mohair. It is to be expected that in Texas more careful attention
will be given to the selection of breeding stock, as well as to providing
conditions most favorable for mohair production.
In addition to its value as a producer of mohair, which is a very
important textile fiber, the Angora goat is useful for clearing brush
1281
YEARBOOK, 1937
from virgin land (fig. 1 illustrates the feeding habits of the animals)
and it is a valuable source of meat. During the fiscal year ended June
30, 1936, a total of 51,461 goats were slaughtered in packing plants
under Federal inspection (13, p. 27), a large proportion of which were
Figure 1. — Angora goats browsing. This is a common scene in the Edwards Plateau
section of Texas. The goats obtain a large part of their feed from the browse that
grows abundantly in this section.
Angora goats. This meat, sometimes known as chevon, is similar
in flavor to lamb and mutton.
Table 2. — Production of mohair (including kid hair) and estimated average uvight
of mohair fleeces per goat in the 6 leading producing States at 5-year intervals from
1920 to 1935, inclusive
1920
1925
1930
1935
State
Produc-
tion
Fleece
weight
Produc-
tion
Fleece
weight
Produc-
tion
Fleece
weight
Produc-
tion
Fleece
weight
1,000
pounds
6,786
397
404
452
145
230
Pounds
3.7
3.2
3.2
4.0
2.5
3.6
1,000
pounds
8,619
444
599
462
188
220
Pou nds
4.6
3.7
3.7
4.2
2.8
4.4
1,000
pounds
14,800
815
900
480
168
140
Pounds
4.2
3.9
4.0
4.0
2.5
3.5
1,000
pounds
13,000
920
480
331
210
133
Pounds
4.6
4.1
3.2
3.8
2.5
3.8
Total or average
8,474
3.6
10,432
4.4
17, 303
4.1
15,074
4.4
Bureau of Agricultural Economics, U. S. Dept. of Agr.
ANGORA GOATS 1285
Goat meat, according to Williams (19), goes quite generally into
the regular meat trade. In cities and towns in the range districts
Angora wethers are marketed freely as such and the meat is consumed
without discrimination by the buyer. According to some buyers
properly finished goat meat has a sweetness lacking in mutton . Studies
by Miller 3 indicate that the flavor of the meat from kids and lambs
is very similar ; in fact, the flavor was identical as far as tbe committee
judging the two types of meat could decide. The goat meat was a
little coarser in texture and for the older goats was graded as slightly
tougher and somewhat drier. In eastern markets the status of goat
meat has never been established and occasional efforts to sell it in
these markets have been disappointing.
In general the goat carcass is not so well-fleshed, it is not susceptible
of so high a finish, nor is the dressing percentage so high as that of
the average sheep carcass. The selling price of the Angora wether
is about 60 percent of that of the sheep wether where large numbers
are sold. The lower price of chevon meat is attractive to consumers,
and the quality of the meat is probably superior to that of mutton
that could be obtained for the same price (19).
Improvement Brought About by Selective Breeding
The improvement of Angora goats in the United States has come
about through selective breeding. Following the early importations,
imported bucks were used extensively on a foundation of common
short-haired does. Through selection and the use of imported bucks
improvement progressed until the supply of high-class stock is now
so plentiful that cross-breeding is seldom practiced. At present the
chief method of breed improvement is based on a program of selection
within purebred Angora stocks. Figure 2 shows a buck and a doe
representative of the breed.
For the most part, the range herds of Angoras are composed of
high-grade does that are mated with purebred bucks obtained from
breeders who specialize in the production of registered animals.
Most of these breeders are in the States of Texas, Oregon, New
Mexico, and Arizona.
Agencies That are Sponsoring Breed Improvement
In 1900 the American Angora Goat Breeders' Association established
a registry system for Angora goats. The foundation animals admitted
to registry were chosen after official inspection of high-grade American
Angoras, and only animals conforming to the standards required by
the association were admitted. From 1900 to 1924 all goats registered
by this association traced to these foundation animals or to Angoras
imported during this period. In 1918 another association, the Na-
tional Angora Record Association, was organized and. incorporated
under the laws of Texas, but this association merged with the American
Angora Goat Breeders' Association in 1924. At present the latter
association is the only organization registering Angora goats in the
United States. Up to 1937 a total of about 170,000 Angora goats have
been registered. Claudine Bourland of Rock Springs, Tex., is the
secretary of this association. The directory of the association, pub-
8 Milleb, R. II. Quality and palatability or chevok. Master's thesis, Oreg. State Col. 1929.
1286
YEARBOOK, 1937
lished in October 1934, lists a total of 353 members, 2GG of whom are
in Texas.
Other organizations that are active in sponsoring Angora goat
breeding and improvement are the Arizona Mohair Growers' Associa-
tion and the Texas Sheep and Goat Raisers' Association.
The Angora Journal, published at Portland, Oreg., by A. C. Gage,
is the only journal in the United States that specializes exclusively
Figure 2. — An Angora buck and doe in full fleece. These individuals
are good representatives of the breed.
on the promotion and improvement of Angora goats. The South-
western Sheep and Goat Raisers' Magazine is the official publication
of the Texas Sheep and Goat Raisers' Association.
RESEARCH, INCLUDING THAT AT FEDERAL
AND STATE STATIOPsS
Research pertaining to Angora goats either by States or by the
Federal Government is very limited. At present, only three projects
are listed in the Office of Experiment Stations that deal with Angora
goats, and these are all being conducted at the Texas Agricultural
Experiment Station. They cover:
1. The inheritance of type in Angora goats.
2. Inheritance of the ndgling 4 characteristic in goats.
3. Cytological and hybridization studies with goats.
In 1915 the Texas Agricultural Experiment Station established a
branch experiment station, generally known throughout the South-
west as the Ranch Experiment Station, in the Edwards Plateau
section midway between Sonora and Rock Springs (fig. 3). Much
'Ridglimts or "rigs" are animals characterized by cryptorchidism, the condition in which one or both
testes fail to descend into the scrotum. Vsually it involves but one testis, but occasionally both.
ANGORA GOATS
1287
of the research at this station has been devoted to a study of Angora
goats and mohair, and several bulletins have been published dealing
with various aspects of mohair production, particularly studies on
the influence of such factors as age, sex, individuality, and pregnancy
upon the quantity and quality of mohair produced. The Bureau of
Animal Industry of the United States Department of Agriculture has
Figure 3. — The laboratory building at the Texas branch experiment station near
Sonora, Tex. This is the only research institute in the United States that is carrying
on investigations with the Angora goat.
cooperated in some aspects of these investigations, chiefly on studies
pertaining to quality of mohair.
Several years ago the Oregon Agricultural Experiment Station
maintained an experimental herd of Angora goats, but with the
curtailment of funds for research that followed the depression, this
herd was disbanded.
Results of the Germ-Plasm Survey
As a part of the survey of germ plasm in animals and plants, the
Department of Agriculture sent questionnaires to agricultural experi-
ment stations in those States where Angora goats are of considerable
economic importance and also to all prominent breeders whose names
could be obtained. The breeder was asked for information concerning
(1) the size of his herd, (2) the number of purebred and grade goats
in the herd at present and during each of the last 5 years, (3) the total
yield of mohair for each of the last 5 years, (4) the number of sires
used in the herd, (5) the proportion of single and multiple births
observed during the last 2 years, (6) the names of any outstanding
strains bred by him, and (7) whether he was practicing inbreeding.
If he was practicing inbreeding the breeder was requested to furnish
pedigrees of several of his most highly inbred animals.
There were very few returns from the questionnaire, and as a
result no very definite conclusions can be drawn. Some breeders
1288 YEARBOOK, 1937
reported that they were practicing some inbreeding, but no pedigrees
from which the degree of inbreeding could be determined were
included in their replies. Nor is this information available anywhere
in published form, since the record association does not publish herd-
books. While a few breeders have attempted to develop and maintain
certain breed lines, the number of attempts to do this is small and no
families that could be compared with some strains of cattle — as, for
instance, the Anxiety 4th Herefords — were reported. It is improbable
that such strains exist among Angora goats. Some breeders follow
the plan of using bucks produced in their own herds; others the plan
of purchasing sires from other herds; while some use a combination of
both plans. Since no importations have been made in recent years,
little improvement has recently been accomplished in this manner.
Apparently there has been a tendency among Angora breeders to
breed for definite points such as certain fleece types, the elimination
of beards, etc., rather than for the development of breed lines of
especial merit.
From the data submitted it is apparent that mohair production in
the flocks of the better breeders is much above the average reported
in table 3. Two breeders reported an average annual production per
goat during the last 5 years of over 7% pounds; others, an average
annual production of over 6 pounds. These figures are from 2 to 3
pounds, or some 40 to 70 percent, above the estimated average pro-
duction for all Angora goats.
No great tendency was observed in any of the herds reported for
the production of multiple births. A considerable reduction has been
made in the size of some purebred flocks since 1930.
Genetic and Fleece Studies on the Angoka Goat
Only a few investigators have studied the genetics of the Angora
goat and most of the studies reported thus far are in their preliminary
stages. Warwick (16) found that the presence of horns is dominant
to hornlessness in the Angora and he suggests that one major factor
governs the inheritance of this character, although the data are too
few to allow for definite conclusions. Most purebred Angora goats
have horns.
Cryptorchidism, an inherited defect that is quite common in Angora
goats, has been investigated by Lush, Jones, and Dameron (8), and
by Warwick (15). The exact mode of inheritance is not known, and
its determination is difficult since the defect can be observed only in
the male. The condition is recessive and at least two pairs of factors
are involved.
The mode of inheritance of fleece length has not been determined,
but Davies (3) states that the long-haired condition appears to be
recessive. From the meager evidence available, however, it seems
probable that hair length is determined by multiple factors.
The effect of individual differences and of such factors as age, sex,
pregnaney, and lactation on the quality and quantity of fleeces
produced by Angora goats has been investigated by Lush and Jones
(7), and by Jones, Warwick, Dameron, and Davis (6). The studies
by Lush and Jones show that about 17 percent of the differences in
fleece weight produced bjr goats similar in age, sex, and general breed-
ANGORA GOATS 1289
ing is permanent throughout the life of an individual and hence is
subject to selection. The exceptional individual is of more importance
in the less uniform flocks, and it is in such flocks that selection would
be most effective. It was determined, furthermore, that permanent
differences in fleece weight show up less accurately at first shearing
than at later shearings and that they show more accurately at the
fall yearling shearing, usually the second shearing, than at any other
age. This is an important determination from the breeder's stand-
point since culling at this age will result in the selection of those goats
with the greatest inherent mohair production.
Jones, Warwick, Dameron, and Davis (<3) found that the age of
the animal had a marked influence on both the unscoured and the
clean weight of the fleece, the weight increasing to a maximum at
3 years, after which it becomes steadily less. Diameter of mohair
Jiber and body weight were shown to increase until the animal reached
8 years of age. Length of staple, amount of kemp or coarse inferior
hair in the fleece, and the extent of belly covering were somewhat less
influenced by the age of the animal. Staple length reaches its maxi-
mum the first year and the mohair produced during the first year is of
somewhat better quality than that produced later.
The body weight of bucks was found to be about 23 percent greater
than that of does, while their fleece weights averaged about 18 percent
greater unscoured and 29 percent greater when clean. The diameter
of fiber was observed to be coarser in the fleece of the male but the
staple length was somewhat less. Pregnancy was shown to reduce
the fleece weight, as did the suckling of young. A somewhat similar
effect of pregnancy was observed upon staple length although this
effect is more pronounced in younger than in older animals.
Attempts to Cross the Sheep and Goat
Various investigators (11) have described apparent sheep-goat
hybrids and a few writers have stated that such hybrids are rather
common in some sections. Other workers have questioned these
conclusions, and in the light of controlled attempts to make this
cross it is probable that living hybrid offspring are rare, if they exist
at all.
Heller, cited by Popcnoe (10), reported that attempts to make such
crosses between Barbados sheep and the goat in the laboratories of the
Bureau of Animal Industry wore unsuccessful. Recently Warwick,
Berry, and Horlacher (18) described attempts to cross Angora does
with rams, mostly of the Merino breed. In all 38 such matings were
made. In 21 females it was determined that fertilization and im-
plantation of the egg took place, but in no case were living young
obtained. Two of these does were sacrificed, one 44 days after breed-
ing and the other 62 days after mating. In both cases apparently
normal embryos were found. The causes for the early death of the
hybrid fetuses have not been determined.
Not all rams that were tried would mate with the does and, con-
trary to general opinion, Angora males would not mate with ewes.
However, one Angora male that was raised on a sheep foster mother
was mated with 17 ewes, but there is no evidence that fertilization
occurred in any of these cases (17).
138004°— 37 82 +
1290 YEARBOOK, 1937
OPPORTUNITIES FOR FURTHER IMPROVEMENT
It is apparent from the facts presented here that credit for improve-
ment of Angora goats must go to private breeders, past and present,
who alone have been responsible for bringing this breed to its present
development. But improvement is now very slow, and if further
progress is to be stimulated and encouraged, new measures are called
for. On this point few will disagree, but the breeder may well ask
what steps can be taken to bring about further improvement. It
must be confessed that there is no single easy formula. If further
improvement is desired, what will be needed is a program that includes
the active cooperation of breeders, breed associations, State' and
county extension workers, and finally, the research staffs of State
and Federal experiment stations.
No attempt will be made here to outline a research program for
Angora improvement, but some of the points that need be considered
will be briefly discussed.
One of the most urgent needs for breed improvement in all branches
of livestock husbandry at the present time is the development of more
and better criteria for the selection of breeding animals. Too gen-
erally, selection is based solely on the animal's appearance, or pheno-
type, and it is a well-known fact, substantiated both by practical
experience and by genetic evidence, that appearance is not always a
good criterion of an animal's breeding worth. It is of value and must
be taken into account, but it is only part of the story. The question
is, not what an animal looks like, but what inheritance it will pass
on; and it is impossible to determine this from appearance. How to
determine it is a question that science is as yet far from having
answered in the case of animals. Research workers are attacking
the problem, however, and eventually methods should be devised for
determining and evaluating the factors of greatest importance in the
selection of breeding stock.
Meanwhile, in spite of present uncertainties, it is known that the
progeny test is important in evaluating breeding animals. To use
the progeny test properly, however, requires the development of
better records than those that now exist for mohair production. This
is one part of an improvement program in which the practical breeder
can cooperate to advantage with the scientist. Before such tests are
undertaken, however, careful thought must be given to the kind of
records that will be of the greatest use.
To use the progeny test most effectively the breeder must have
accurate data on the offspring of his herd sires. Among the records
of most importance are quality of mohair, freedom from kemp, uniform-
ity of body covering, and yield of mohair determined on a clean basis.
While facilities are probably not now available for securing all such
information, records could undoubtedly be obtained if there were a
sufficient demand for them. In addition to their value to the breeder
in the selection of sires, such records would be of use to the scientist
in getting at the basic physiological problems concerned in mohair
production; and a more complete knowledge of such factors is essen-
tial to continued progress.
Very little information exists concerning the inheritance of any
characters in the goat and particularly of those characters that are
ANGORA GOATS
1291
concerned in the production of good fleeces. Research in this field
is badly needed, since progress in breeding for fleece improvement must
ultimately depend on a better understanding of the genetic, factors
involved. As an example, take the appearance of kemp in the fleece
(fig. 4). The elimination of kemp fibers, which greatly reduce the
value of the fleece, is one of the most important problems in Angora
goat improvement. Until it is known how the kemp-producing charac-
teristic is inherited, it can hardly be eliminated from herds.
There are now outstanding animals in the herds of many breeders,
but along with them there arc manv mediocre and some inferior
Figure I. — Cross sections of mohair fibers showing (A) freedom from kemp and (B)
the presence of many kempy fibers. The kempy fibers, which are short, coarse,
and irregular, are characterized by a uicdullated or hollow central portion. They
do not take dye readily, and because of this and their stiffness and poor spinning
qualities, the presence of such fibers in a fleece lowers its value.
animals. If it were possible for the breeder to increase the uniformity
of the animals in his flock it would be a decided step forward. Little
is now known of the factors making for uniformity of fleece type,
although this question is of vital concern to the breeder and the
producer alike. Research that will lead to the development of
methods for improving uniformity in flocks is badly needed.
These are two problems that should form part of a research pro-
gram. Others might be discussed, but enough has been said to
indicate the need for a scientific approach to the problem of improve-
ment. Research commonly yields large returns for the funds and
efforts expended, but the active encouragement of the industry is
needed if an adequate research program for the improvement of
Angora goats is to be carried on.
Some Immediate Practical Steps
In addition to sponsoring research Angora goat producers might
foster improvement in other ways. One method that has particular
merit would be the development of a system of recording based on
1292 YEARBOOK, 193 7
meritorious production of mohair similar to the register of merit for
many breeds of dairy cattle. In such records scoured weight, fineness,
and uniformity of fleece and freedom from kemp should be partic-
ularly stressed. Other steps that would be helpful would be the inclu-
sion of more information in pedigrees than they now contain, with
provision for certification of production records by some competent
and impartial authority. Since Angora goat breeders are concen-
trated in a relatively few States, it should be possible to arrange for
such certification of records with a minimum of cost to breeders.
Such programs have been developed for register-of-merit records for
other animals, and a similar scheme could be easily devised that would
meet the requirements for breeders of Angora goats.
Again, if mohair were sold on a quality rather than on a weight basis
it would exert an influence toward improvement in the breed by
stimulating producers to raise better goats. This is worth serious
effort on the part of the breeders and their record association. The
adoption of different methods for the awarding of prizes at shows
would also be a step to encourage better breeding practices. More
emphasis should be placed on the get of sires and on outstanding fam-
ilies, and prizes should be awarded to breeders on this basis. This is
in line with the progeny test, and it would focus the attention of
breeders on the breeding ability of their choice animals.
Many difficulties beset those who undertake the improvement of
modern breeds of livestock. But in spite of the excellence of modern
breeds, their inherent variability is still great and the opportunities
for improvement are many. The situation is a challenge to breeder
and scientist alike, and if any great progress is to be made they must
work closely together.
BIBLIOGRAPHY
(1) Black, W. L.
1900. A XEW INDUSTRY, OR RAISING THE ANGORA GOAT AND MOHAIR FOR
profit. 486 pp., illus. Fort Worth, Tex.
(2) Cronwright Schreiner, S< C.
1898. the angora goat . . . 296 pp., illus. London and New York.
(3) Davies, C. J.
1912. heredity in goats. Mendel Jour. 3: 104-116, illus.
(4) Hardy, J. I.
1927. studies of the occurrence and elimination OF KEMP FIBERS
in mohair fleeces. U. S. Dcpt. Agr. Tecli. Bull. 85, 16 pp.,
illus.
(5) Jones, J. M., and Warwick, B. L.
1930. inheritance of type in angora goats. Tex. Agr. Expt. Sta.
Ann. Rept. 43: 24-25. .
(6) Warwick, B. L., Dameron, W. H., and Davis, S. P.
1935. effect of age, sex, and fertility of angora goats on the
quality and quantity of mohair. Tex. Agr. Expt. Sta. Bull.
51 6, 34 pp., illus.
(7) Lush, J. L., and Jones, J. M.
1924. the influence of individuality, age, and season upon the
weight of fleeces produced by angora goats under range
conditions. Tex. Agr. Expt. Sta. Bull. 320, 54 pp., illus.
(8) Jones, J. M., and Dameron, W. H.
1930. the inheritance of cryptorchidism in goats. Tcx. Agr. Expt.
Sta. Bull. 407, 23 pp., illus.
(9) Lydekker, R.
1898. wild oxen, sheep & goats of all lands, living and extinct.
318 pp., illus. London.
ANGORA GOATS 1293
(10) [POPENOE, P.], Cd.
1915. ancestry of the goat. Jour. Heredity 6: 519-524.
(11) Roberts, J. A. Phaser, and Crew, P. A. E.
1925. the genetics op the sheep. Bibliographia Genetica 2: [261]-286.
(12) Rose, P. D.
1924. angora goat industrt in south aphica. Jour. Dept. Agr. Union
So. Africa 8: 230-237.
(13) United States Department op Agriculture, Bureau op Animal
Industry.
1936. annual report op the chief op the bureau of animal indus-
try, 1936. 60 pp.
(14) United States Department op Commerce, Bureau op the Census.
1931-32. fifteenth census op the united states: 1930.
(15) Warwick, B. L.
1933. INHERITANCE OF THE RIDGLING CHARACTER IN GOATS. TeX. Agr.
Expt. Sta. Ann. Rept. 46: 28.
(16)
1933. INHERITANCE OF HORNS IN ANGORA GOATS. Tex. Agr. Expt. Sta.
Ann. Rept. 46: 39.
(17) Berry, R. O., Hogan, A., and Horlacher, W. R.
1935. CYTOLOGICAL AND HYBRIDIZATION STUDIES WITH SHEEP AND GOATS.
Tex. Agr. Expt. Sta. Ann. Rept. 48: 36-37.
(18) Berry, R. O., and Horlacher, W. R.
1935. RESULTS OP MATING RAMS TO ANGORA FEMALE GOATS. Amer. SoC.
Anim. Prod. Proc. (1934): 225-227.
(19) Williams, G. P.
1936. the angora goat. U. S. Dept. Agr. Farmers' Bull. 1203, 22 pp.,
illus. (Revised.)
(20) Willingmyre, G. T., Window, J. J., Spencer, D. A., Hardy, J. I., Chap-
line, W. R., Fitzpatrick, F. E., and Schoffstall, C. W.
1929. the angora goat and mohair industry. U. S. Dept. Agr. Misc.
Circ. 50, 120 pp., illus.
IMPROVEMENT
OF MILK GOATS
V. L. SIMMONS, Assistant Animal Husbandman, and
W. V. LAMBERT, Senior Animal Husbandman,
Animal Husbandry Division, Bureau of Animal Industry
jTjlCCORDING to a recent survey by the United States Department
of Agriculture, only two research institutes in the United States are
now conducting investigations on milk goat breeding. Both institu-
tions, the New Mexico Agricultural Experiment Station and the
Department of Agriculture, have brought about great improvement
in their herds by grading up common does with purebred bucks of
milk breeds, and the results indicate great potentialities for milk goat
improvement by the application of breeding methods.
THE GOAT AS A MILK PRODUCER
Milk goats are widely distributed in the United States but, in con-
trast with Angora goats, they are generally found in small herds and
in many cases as one or a few individuals kept on the farm or in the
back yard of the urban dweller. While they have not attained the
position of economic importance of other classes of livestock, their
numbers are increasing. Because a good milk goat will supply suffi-
cient milk for the average family for at least 9 to 10 months of the
year and can be kept where it would be impossible to keep a cow, they
occupy a place in American agriculture not filled by any other class
of livestock, and one that is probably destined to be increasingly
important.
The average milk production is low, but there are many high-pro-
ducing individuals and some herds in which the average milk produc-
tion is high. Great variability exists both in rate and persistency of
lactation.
The income of milk goat producers is derived principally from two
sources — the sale of breeding stock and the sale of milk and milk
products. Goats' milk has only a specialized demand and the devel-
opment of goat dairy enterprises has been limited largely by the
market created by the producer's own initiative. The producer of
good breeding stock, on the contrary, has been in a more favorable
position, for generally a greater demand exists for good stock than
can be supplied.
Goat meat and goatskins also contribute to a limited extent to the
income of the goat producer. Thousands of goats are slaughtered
annually and their meat enters the same general channels of trade as
mutton and lamb. Their skins are used in the manufacture of shoes,
gloves, book bindings, pocketbooks, and other small articles. The
number of skins produced annually in the United States is not large
1294
MILK GOATS 1295
and millions of skins are imported each year. From July 1934 to
July 1935 a total of about 60 million pounds of skins were imported.
Breeds of Milk Goats in the United States
The goat is one of the most ancient of domestic animals. Most
authorities agree that the numerous varieties are descended from the
Persian wild goat, Capra hircus aegagrus, a species common in Asia
Minor. Just when it was first introduced into Europe is unknown,
but remains of goats are found among the ruins of early European
races.
Becords of early settlements in Virginia and New England indicate
that goats of the milk type were brought to the United States by Capt.
John Smith and by Lord Delaware. Goat raising, while of some conse-
quence to the early settlers, gradually declined after the middle of the
seventeenth century.
Serious attention began to be paid to the breeding of milk goats in
the United States about 30 years ago. Prior to 1904 there were
scarcely any purebred Swiss goats in the United States, records
revealing but one importation, that of four head in 1893. In 1904 a
consignment of 10 Saanen and 16 Toggenburg goats was brought in,
and this was followed by several other importations during the next
two decades. Animals from these importations were widely dispersed
by sale throughout the United States, and have provided the basis for
the development and improvement of milk goats in this country.
The important breeds of milk goats in the United States are those
that have proved most popular on other continents — the Saanen,
Toggenburg, Nubian, Maltese, and Alpine. Representatives of these
breeds of improved milk goats, although increasing, are not so
numerous in this country as the unimproved types of short-haired
goats. Among them are large numbers of the common, or American,
goat. A quarantine against the importation of goats from many
countries largely accounts for the small number of breeds found in
the United States.
A GOAT can be kept where it would be impossible to keep a cow,
and a good producer will supply sufficient milk for the average
family. The milk is a wholesome and nutritious food, and in
addition the meat is palatable and nutritious. In localities where
an adequate supply of milk is not available and the keeping of
cows is impracticable, good milk goats would contribute materially
to the welfare of many families, especially those of low income.
Thus there can be no doubt of the value of efforts to improve the
milk production of these animals in the United States. However,
the improvement of the milk goat, in common with that of other
species of livestock, is a large task that requires the best efforts of
the breeder, the research worker, and all other interested agencies.
1296
YEARBOOK, 1937
The Saanen and Toggenburg breeds of milk goats are the most
popular in point of numbers in this country. Both breeds originated
in Switzerland. Purebred Saanens (fig. 1, A) are solid white in color
and large in size, mature males weighing 175 pounds or more and
mature females, 125 pounds or more. The dairy conformation is
especially well devel-
oped. The marked abil-
ity of this breed to pro-
duce milk is evidenced
by the fact that the high-
est official test on record
in the United States was
made by a Saanen doe
that produced 4,161.7
pounds of milk in 9
months and 10 days, an
average for the period
of 6.9 quarts a day.
The body color of
Toggenburg goats (fig.
1, B) is brown or choc-
olate with a white stripe
or bar down each side
of the face, and the legs
below the knees and
hocks are white. Two
wattles attached to the
underside of the neck
are very characteristic
Figure 1. — High-producing
does from three different
hreeds: A, Saanen; B, Toggen-
burg; C, Anglo-Nubian. The
Saanen doe (No. 40728, Ad-
vanced Registry No. 191 A.
M . G. R. A.) produced 3,144.4
pounds of milk and 95 pounds
of fat in 10 months. Her
highest daily yield was 17.6
pounds. The Toggenburg
doe (No. 41642) produced 11
pounds of milk daily for a
30-day period as a 4-year old.
Each one of these does came
from high-producing ances-
tors and each has won high
honors in the show ring. The
Anglo-Nubian doe (No. 34278,
Advanced Registry No. 201)
produced under official test as
an 8-year old an average of
12.1 pounds of milk, averag-
ing 5.7 percent fat, daily for
3 months.
MILK GOATS 1297
of this breed. Does of this breed, while not usually producing as large
quantities of milk as those of the Saanen breed, arc excellent milkers
and a Toggenburg doe has made an official record of 2,759 pounds of
milk in 10 months. Toggenburg does, when mature, weigh from 100
to 135 pounds and mature bucks, from 150 to 175 pounds. Owing to
the fact that Toggenburg goats are more plentiful here than other
breeds, a good many grade goats of the Toggenburg type are found in
various parts of the country. In fact, many herds have been estab-
lished by crossing Toggenburg bucks on does of the American type.
Nubian milk goats, although considered a valuable breed, are not
numerous in this country. They are natives of Nubia, upper Egypt,
and Abyssinia. The colors of Nubians are black, dark brown, or
tan, with or without white markings. They have a striking appear-
ance, with drooping ears, a convex face, and a prominent forehead.
Nubian bucks when mature weigh 165 pounds or more and mature
does, 125 pounds or more. The Nubian breed is considered one of the
best for milk production and the milk is noted for its high butter fat
content; however, no figures are available on production for this breed.
There are also some Anglo-Nubian goats in this country. These
are a very popular type of goat in England and are descended from
crosses between the Nubian and goats of English origin. The pre-
dominant colors are black, tan, and red, with or without white. Some
good specimens have shown a color approaching a roan, which is the
color of the doe shown in figure 1, G Anglo-Nubians are considered
good milkers. Richards {21)1 states that Nubians and Anglo-Nubians
are less well adapted to cold climates than are the other breeds.
A scattering of Alpine goats are found in the United States and
trace to an importation of 3 bucks and 18 does brought into Cali-
fornia from France in 1922. The Alpines range in color from pure
white to pure black with frequent white spotting on the neck, legs,
or underneath the body. They are of large size and quite hardy,
and they have excellent capacity for milk production.
The Maltese breed, while considered valuable in some parts of the
world, is of no special importance in this country at present, except that
it has had some influence on the type of goats in the Southwest. It is
native to the island of Malta. The color is white and reddish brown
or black. It is considered one of the best breeds for milk production.
In the southwestern part of the United States there is found a type
of goat known as the Spanish Maltese, which is descended from
crosses between the Maltese and goats of Spanish origin. It is said
that at a former time many Maltese goats were taken into Spain and
from there to Mexico and finally to Texas and New Mexico. This
type of goat is white or grayish in color, but many have brown,
bluish-black, or reddish spots. The ears are pendulous. It is
asserted that some are very good milk producers.
The common, or American, goats (fig. 2, A) found in many sec-
tions of the United States, especially in the South, are of mixed origin.
In many sections these goats have been bred for a groat many years
without the introduction of outside blood, so that in general con-
formation they are nearly uniform, being of medium size, somewhat
short legged, and rather meaty in appearance. They do not show
i Italic numbers in parentheses refer to Bibliography, p. 1312.
J298
YEARBOOK, 1937
Figure 2. — A, Common American doe no. 66 used as one of the foundation does of
the United States Department of Agriculture herd at Beltsville, Md. This doe
produced 367 pounds of milk in a lactation period of 275 days. B, United States
Department of Agriculture doe no. 214. This doe represents the third top cross of
high-producing Saanen bucks on a foundation of common American does. This
doe produced 1,796.3 pounds of milk in a lactation of 266 days.
MILK GOATS
1299
the conformation of the Swiss breeds, and they are of various colors —
brown of various shades, brown and white, black and white, bluish
gray, and white predominate. Although a few goats of this type are
occasionally found that are good milkers, the quantity of milk pro-
duced is usually small and the lactation period lasts only a few
months. Yet by crossing common does with bucks of the Saanen,
Toggenburg, and Nubian breeds for several generations, some of the
very best milkers in the United States have been produced. Because
of the scarcity of good milk goats, common does have been used
largely for grading up with the improved breeds.
Distribution of Milk Goats in the United States and the World
With the exception of the dog, the goat is the most widely dis-
tributed of all domesticated animals, and the genus Capra is found
throughout the world outside of the Arctic regions. Table 1 shows
the distribution of goats of all types for those countries that re-
ported an average of 500,000 or more during the 5-year period
1926-30. Although the types of goats are specified in only a few
instances in census data, it seems probable that the majority of the
goats reported are used for milking purposes. The total number of
goats in the world is estimated at 189,000,000, of which 8,000,000 are
classed as Angora goats.1
Table 1. — Number of goats of all kinds in countries having an average of 500,000 or over
for the period 1926-30
Country
North America and Central America:
United States, total, goats. _ _.
United States, Angora goats
Mexico
Dominican Republic.
South America:
Argentina
Brazil — _
Venezuela.. _ _. — ...
Chile
Bolivia
Peru
Europe:
Spain
Greece.
Germany
Italy
Yugoslavia
Portugal
France
Bulgaria
Czechoslovakia . ...
Albania.
Union of Soviet Socialist Republics.
Africa:
Union of S. Africa, total goals
Union of S. Africa, Angora goats. ..
Nigeria and British Cameroons
Kenya Colony
Morocco
Algeria
Average
numbor,
1926-30
Thou-
sands
1 4, 821
i 3, 785
15,984
oso
1 5, 647
5, 207
2, 155
1789
713
638
4,524
4, 490
3,204
U,892
1, 765
1,579
1, 486
1,261
1,163
790
12,200
7,808
1,588
5, 181
3, 766
3, 072
3,003
Country
Africa — Continued.
Tanganyika Territory
French West Africa (total)
Anglo-Egyptian Sudan
British Somaliland
Uganda
Tunisia
Belgian Congo
British Southwest Africa (total)
British Southwest Africa, Angora
goats
Basutoland
Italian Somaliland
Rhodesia (total) ..
Eritrea (Italian)
French Equatorial Africa
Ruanda and Urundi
Egypt —
Asia:
Turkey, European and Asiatic,
total goats
Turkey, European and Asiatic,
Angora goats
Iraq-Mesopotamia
Porsia (Iran)
Syria and Lebanon.
India:
British
Native States
Dutch East Indies..
Average
number,
1926-30
Thou-
sands
2,873
2,397
2,005
1,800
1, 416
1,370
1,127
1,025
32
956
942
883
642
578
510
615
11,436
2, 925
1,757
8,000
1,566
38, 336
1 0, 836
2,739
i Figures from census of 1930.
i The proportion of Angora to milk goats in the United States is much different from that prevailing in
most parts of the world. According to the 1930 census, milk goats constitute less than one-fourth of the
total number of goats in the United States. In many countries, such as Spain and Germany, the propor-
tion of milk goats to Angora goats is much larger.
1300
YEARBOOK, 1937
The total number of milk goats 2 in the United States can only
be estimated as no specific census figures are available. The total
number of goats of all kinds in 1930 according to the census of that
year was 4,821,000, of which 3,785,000 were specified as Angora goats.
Only a small percentage of the 1,036,000 other goats, of short-haired
type, could be classed as improved milk goats. In 1930 3 the five
leading States in number of short-haired 4 goats and kids were Texas
with 185,737; New Mexico, 102,548; Arizona, 97,628; Georgia,
84,503; and Tennessee, 53,948.
Milk goats are found in practically all sections of the United
States and in recent years have increased in numbers in the Eastern
and Middle Western States. While California ranks eleventh in
total number of short-haired goats, the milk goat industry in southern
California has developed to a greater extent than in any other sec-
tion of the United States. The dry, even climate, the abundance of
feed, both wild and cultivated, and the favorable marketing condi-
tions present opportunities not offered in most sections.
In a number of countries milk goats have been bred for many
years, and in a few countries, Switzerland in particular, they have
been brought to a state of considerable efficiency and perfection.
In Spain goats are the chief source of the milk supply. In Europe
and Asia the goat is used quite generally as a dairy animal, while
in Africa meat and skins are the principal products.
Properties and Uses of Goats' Milk
Goats' milk differs in some respects from the milk of the cow.
Chemical analyses of the two kinds of milk are shown in table 2.
Table 2. — Composition of goats milk ] and that of ftco common breeds of dairy cows
Source of milk
Goat
nolstcin-Friesian
Jersey
Water
Percent
88.02
87.50
85.31
Total
solids
Percent
11.98
12.50
14. 69
Fat
Percent
3.50
3.55
5. 18
Percent
3.13
3.42
3. SO
Lactose
Percent
4.55
4.86
4.84
Ash
Percent
0.80
.OS
.70
1 Average of purebred and high-grade Saanen and Toggenburg does.
Considerable variability is observed in the composition of milk
from different breeds of both goats and cows, between individuals
in the same breed and even in samples taken from the same indivi-
dual, especially when such samples are taken at widely different
periods of lactation. The above results for the goat are based on
analyses of milk from the herd kept by the United States Depart-
ment of Agriculture at Beltsville, Md., while the results for the two
breeds of dairy cattle are from data reported by the Associates of
Rogers
' The term "milk goats" is one applied to goats that have been bred and developed especially for milk
production. The term " Angora" is one given to that breed of long-haired goats which have been bred and
developed especially for mohair production. The term "short-haired goats", as used herein, is one com-
monly applied to unimproved goats of mixed breeding that are sometimes used for milk production. In no
case does the term refer to goats producing mohair.
1 Fifteenth Census of the United States, Agriculture, v. 4. 1930.
4 The term "short-haired goats" as used by the census probably includes some milk goats
'Italic numbers in parentheses refer to Bibliography, p. 1312.
MILK GOATS 1301
Studies by Jordan and Smith (11) showed that there are no essential
differences in the casein of goats' and cows' milk. Similarly, studies
on milk from the Department of Agriculture herd show that there
are no significant differences between these two kinds of milk in con-
tent of calcium, phosphorus, iron, and copper. Studies made in the
nutrition laboratories of the Department on the vitamin content of
goats' and cows' milk showed no marked superiority of one over the
other. Jersey milk was found to contain somewhat more vitamin A,
but goats' milk more of vitamins B and C. It was also determined
that goats' milk has a much softer curd than the milk of either
Holstein-Friesian or Jersey cattle.
Through the cooperation of the Department of Agriculture and
Johns Hopkins University, normal infants were fed Holstein, Jersey,
and goat milk. The milk used in these studies was boiled for 1 minute
and was supplemented with orange juice and cod-liver oil. While the
number of infants fed on any one kind of milk was too small to furnisli
conclusive results, no essential differences in health, general appear-
ance, and well-being of the infants were observed, good results being
obtained with each kind of milk.6 The gains in weight were in pro-
portion to the total nutritive contents of the milk. No attempts were
made to compare the two kinds of milk on infants with a history of
malnutrition. Goats' milk may be of value for infant feeding in cases
of food idiosyncrasies, for many cases are on record in which children
are able to utilize goats' milk, but not the milk of the cow.
The fat globules are much smaller in goats' milk and this charac-
teristic, together with a softer curd, makes it easier to digest than
cows' milk. Because of the small fat globules, which prevent the
cream from rising to the surface, the ordinary method of obtaining
cream by allowing it to rise is impracticable. By the use of the sep-
arator, however, practically all the butterfat can be obtained and it
may be used satisfactorily for making butter. Several varieties of
cheese are also made from goats' milk. To a limited extent, powdered,
condensed, and evaporated goats'-milk products are being manu-
factured in the United States.
No figures are available concerning the total production or con-
sumption of goats' milk and of the products made from it. In general,
there has been only a specialized market for goats' milk and the de-
velopment of goat dairy enterprises has been limited to a large extent
by this market. The price of goats' milk has ranged from 10 to 50
cents a quart and sometimes even higher. There is one brand of
evaporated, unsweetened goats' milk on the market which sells for 25
cents for a can of 6 ounces. This is equivalent to about 65 cents a
quart for the original milk.
Studies on the Physiology of Milk Secretion
Cunningham and Addington (8) studied the effect of early breeding
upon milk production. It was found that does freshening for the
second time at 2 years of age produced significantly more milk than
does that freshened for the first time as 2-year-olds. However, the
does freshening for the first time at 2 years of age had somewhat
0 Four infants were fed on goats' milk and 3 each on Uolstein and Jersey milk. The results were in
conformity with similar comparisons of the 3 kinds of milk on both kids and rats.
1302 YEARBOOK, 1937
longer lactation periods. The greater production of the goats freshened
first as yearlings is contradictory to the belief of many goat breeders.
The question of breeding does early or late in the lactation period
has been studied by Brooks (5). He found that while delayed breed-
ing tends to prolong the lactation period indefinitely, the later pro-
duction is at a much lower level. Furthermore, breeding early in the
lactation period did not seem to decrease the rate of production during
the first part of lactation.
The goat is a seasonal breeder. Turner (26) investigated this ques-
tion for goats of various breeds in the United States and found that
estrous cycles in normal does occur quite regularly at intervals of about
21 days during the period from September to February. During the
months from April through July, and perhaps mostly through August,
estrous cycles are generally suppressed. Similar findings were reported
by Kupfer (18) for goats in South Africa and in Switzerland.
By the injection of an extract prepared from the anterior lobe of the
pituitary gland, Asdell (2) was able to bring about some improvement
in milk secretion of goats in the late stages of lactation. No improve-
ment was observed from injections made early in lactation, especially
in the better milkers. Evans (9) was able to induce lactation in sev-
eral virgin milk goats following the injection of a pituitary extract,
and in one mature goat during her dry period. In cattle he reports
that the Bureau of Dairy Industry of the U. S. Department of Agri-
culture has been able to get increases in milk yield following the
injection of pituitary extract in some low-producing cows that appar-
ently had a deficiency of this hormone. The yield returned to former
levels as soon as the injections ceased. Good-producing cows did not
respond. These results indicate that there is a relationship between
the secretion of the pituitary body and the ability to lactate, but
sufficient information is not yet available to make it possible to use
this information in a practical way.
Turner and Reineke (27) observed that involution of the mammary
gland (shrinking of the secretory tissue) was almost complete in a goat
in the late stages of lactation, and that the stimulation of milking was
ineffective in maintaining the secretory tissue in such goats. Their
results suggest that attempts to increase the milk flow by the use of
hormones will fail unless growth of the secretory tissue is first induced.
RESEARCH AND PRACTICE LOOKING TOWARD
MILK GOAT IMPROVEMENT
In 1936 the Department of Agriculture undertook, as a part of the
germ-plasm survey, to determine the status of milk goat breeding in
the United States. Questionnaires were sent to experiment stations
in those States where milk goats are raised in large numbers, and also
to important private breeders whose names had been obtained from
State experiment stations and from breed association secretaries.
The following information was requested: (1) The namo and registra-
tion number of important sires; (2) the number of each daughter and
her dam; (3) the age when the doe was tested; (4) the number of days
in milk; (5) the pounds of milk produced; and (6) the pounds of
butterfat produced, and the percentage of butterfat, for each daughter
and her dam.
MILK GOATS
1303
The returns from private breeders were limited. While there are
some herds of fairly large size, it appears that few breeders are keeping
records on milk and butterfat production, although many breeders
expressed a desire for such records and a willingness to cooperate in
the keeping of records. Certainly no progress in locating superior
germ plasm can be made until better records exist than those now
available.
From this survey it was also determined that New Mexico is the only
State now conducting research on milk goat breeding. This station
has had an extensive breeding program under way since 1919 and the
results are discussed in a later section.
Research in Milk Goat Breeding in the
Department of Agriculture
Research was initiated with milk goats by the Bureau of Animal
Industry in 1909 with the breeding of common or American does to
bucks of the same type, with the purpose of developing a superior
strain for milk production. Progress was slow and difficult and after
2 years of experimentation of this sort purebred bucks of both the
Saanen and Toggenburg breeds were obtained for grading up the com-
mon does. The lines started from the top crosses of the original does
by males of these two breeds were kept distinct. In each generation
the best producing does were retained for top-crossing in the succeed-
ing generation.
Progress has been slow since only a relatively small number of breed-
ing does could be maintained and breeding activities were curtailed at
various times. However, there has been some progress. The average
length of the lactation period for the top-cross does, on the basis of the
1934 and 1935 results, has increased 145 percent and the average
annual milk yield, 335 percent over that of the native does.7 It should
be pointed out that only six native does were available for comparison
and the average length of lactation for these does was only 113 days.
The influence on both milk yield and length of lactation as a result
of continuous top-crossing with purebred bucks is shown in table 3.
With few exceptions, the does were approximately 24 months old at
the beginning of lactation.
Table 3. — Influence of top-crossing with purebred bucks on the milk yield and length of
lactation of does during their first lactation
Grade of
does1
Milk yield
Lactation period
Increase in
Does (number)
First 120
days (aver-
age)
Range during
first 120 days
Total aver-
age length
Range in
length
average
milk yield
over natives
Native
H
H
Purebred
Pounds
a 325. 2
'417.6
466.7
470.4
496.0
491.4
523.9
Pounds
253. 2-445. 2
376.8-450.0
295. 5-554. 6
313.3-698.2
306. 2-707. 0
156. 7-807. 8
298. 6-765. 0
Days
113
256
273
235
256
244
278
Days
107-122
230-276
205-333
137-309
144-366
122-302
227-340
Percent
5 ._ __ ...
28.4
g . -
43.5
13
44.6
13 -.
52.5
13
51.1
61.1
1 Proportion of pure breedng.
' Estimated milk yield for first 120 days.
i Total annual milk yield is dependent on increased production and persistency in lactation. Much of the
increase in annual milk production of the top-crossed does was due to their greater persistency in lactation.
1304
YEARBOOK, 1937
Since the length, of lactation varied greatly, the quantity of milk
produced by each doe during the first 120 days of her first lactation is
used as a basis for the comparison of the productive abilities of does of
the different top-cross generations.
As the trend in improvement of milk yield was similar for the
top-cross does from the Saanen and Toggenburg bucks, the results
for the two breeds were combined. A doe of the third top cross
is shown in figure 2, B. The milk production of the does from the
fourth and fifth top-cross generations was almost equal to that of
the purebred does in the herd. No production data are available for
grade does of more than thirty-one thirty-seconds pure breeding. A
fourth top-cross doe produced 2,221 pounds of milk in 355 days,
while the best purebred doe produced 2,297 pounds in 312 days.
A number of the grade does had production records exceeding 1,600
pounds for one lactation.
The length of the lactation period also was increased as a result
of the top-crossing, although a large part of the improvement was
observed in the first top-cross generation. Since only six native
does were tested, the average of 113 days observed for them may
havo been lower than the average for the population of does from
which they were chosen.
A comparison of the milk production of does of different ages in
the Department herd is shown in table 4. These results show that
the period of maximum milk production for does is between 4 and
6 years of age. The length of lactation period also is greatest between
the ages of 4 and 6 years but the change observed in length of lacta-
tion was not so great as that for milk production.
Table 4. — Average milk yield of does of various ages in the Department of Agriculture
herd at Beltsville, Md., 1930-35
Age of does
Does
Average
milk
yield
Average
lenpth
of
lactation
period
Age of does
Does
Average
milk
yield
Average
length
of
lactation
period
Years
2
Number
28
19
17
12
Pounds
964.8
1, 173. 5
1, 449. 1
1,424.4
Days
255
281
299
276
years
6.
Number
12
7
4
Pounds
1,427.1
1,335.8
1.196.2
Days
286
3.
268
4
8
266
A comparison of the purebred sires used in this herd, as measured
by the sire index (calculated by the commercial form of the Mount
Hope index, as described by Prentice {20)), showed that marked
differences exist in the ability of sires to transmit their characteristics
to their offspring. None of the sires possessed the necessary in-
heritance for raising both the milk yield and the length of the lacta-
tion period of all his daughters.8 However, more sires increased the
milk yield of their daughters than increased the length of the period
of lactation.
1 This study would indicate that all the sires compared are heterozygous for some of the genes affecting
milk yield and length of the lactation period.
MILK GOATS
1305
Research at the Neav Mexico Agricultural Experiment Station
Since 1919 the New Mexico Agricultural Experiment Station has
conducted experiments to determine the improvement that might be
expected from grading up native does of the Southwest with purebred
Toggenburg bucks. The native does were descendants of the goats
brought into the United States by the Spaniards. Since its initia-
tion, the experiment has been expanded to include such studies as
the inheritance of horns and wattles, length of gestation, prolificacy,
the sex ratio, and a determination of the effects of inbreeding and
outcrossing on milk production, and the birth weight of kids.
The foundation animals for the breeding experiment consisted of
10 native yearling does that came from a herd in which there was
no apparent evidence of improvement by the use of improved bucks
of either Angora or milk type. Milk records were secured on 8 of
the 10 foundation native does and their progeny.
The improvement in production resulting from top crosses of
purebred Toggenburg bucks on native does and their resulting off-
spring is shown in table 5 in comparison with the production of pure-
bred does. Each of the does was approximately 2 years old at the
beginning of her lactation period. In all cases the quantity of milk
produced by a doe was corrected to a butterfat basis of 4 percent
by use of the formula of Gaines and Davidson (19). ,9
Tabtje 5. — The effect on milk production of using purebred Toggenburg bucks on native
does and their offspring
Breeding
Native does
Vi Toggenburg
H Toggenburg
Vs. Toggenburg
lr}ie Toggenburg. _.
Above 1He Toggen-
burg
Purebred Toggen-
burg _..
Ani- i
nials
Milk
Num-
ber
8
22
30
27
19
10
22
Pounds
622.2
1, 059. 7
1, 133. 0
1, 319. 4
1,505.2
1,311.4
1,488.7
Butterfat
Per-
cent
5.0
3.99
3.02
3.61
3.73
3.82
3.76
Pounds
20.14
42.23
41.14
47. 60
56.10
50.03
55. 96
Fat-eor-
rected
milk
Pounds
B11.0
1. 057. 6
1,070.3
1. 241. 7
1,444.7
1, 274. 7
1, 436. 7
Length
of lacta-
tion pe-
riod
Days
230
279
282
288
303
300
293
Gain
over na-
tive
does '
Percent
0
73
75
103
136
109
135
Dam-
daughter
pairs
Number
Daughters
higher than
dams in
f. c. m.s
A"M7ft-
ber
Per-
cent
95
32
SI
50
20
63
1 Gain is based on increase in production of fat-corrected milk.
1 Fat-corrected milk.
Marked increases in milk production were obtained from the top-
cross does, the greatest increase occurring in the first generation.
From the fourth top cross, does equaling the production of the pure-
bred females were obtained.
A number of does in the station herd have made creditable records
under the rules for advanced registry of the American Milk Goat
Eecord Association, several being leaders in their respective classes.
One of these, Val Verde's Zula 25467, has a record of 2,759.0 pounds of
milk and 100.2 pounds of fat. Another, NMAC Mary Ann, a
daughter of Val Verde's Zula, has a record of 2,570.4 pounds of milk
• This formula is as follows: f. c. in. (fat-corrected milk) =0.4 m+lo f. M represents weight of milk and t
weight of fat. This formula expresses the energy produced by an animal in the form of milk and butter-
fat as an equivalent amount of 4-percent milk.
138004°— 37- 83 ++
1306
YEARBOOK, 1937
and 77.08 pounds of fat, while several others have records exceeding
2,500 pounds of milk and 90 pounds of fat. Two of these high-pro-
ducing does, Laura Lorenzo 35768 and NMAC Amenta 35769, are
twins.
During the course of the experiment at the New Mexico Station,
line-breeding has been- practiced to three outstanding bucks in an
attempt to fix the desirable characteristics of the family from which
these bucks came. The production of the inbred and outbred
daughters from these males is shown in table 6.
Table 6.-
A comparison of inbred and outbred daughters from three outstanding sires
in the J\Teiv Mexico herd
Name and no. of sire
Leonidas 3820 (A. M. CI. It. A.)=
Rosemont's Angelus 13201 (A. M. G.
It. A.)!
Val Verde's Lorenzo 30551 (A. M. G.
B. A.)> —
In-
breed-
ing r
Average produel ion of- -
Inbred daughters Dams of inbreds
Tested!
Xui fi-
ber
Milk
Bulterfat
Milk
Los .
lluttorfat
Lbs.
Lbs.
Pet.
Lbs.
Pd.
1, 080. 3
39. 27
3.63
1,0(13.4
47.43
4.33
1, 108. 2
34. 30
3.09
949.8
28. 97
3.05
1.101.4
46.12
4.18
1,176.4
42.43
3.61
1, 30(1. 9
50. 00
3.90
1, .123. 6
58.23
3.82
1,218.0
49.20
4.04
1,278.5
47.26
3.69
Name and no. of sire
Average production of—
Outbred daughters
Darns of outbreds
Leonidas 3820 (A. M. G. It. A.)! .:...
Rosemont's Angelus 13201 (A. M. G. It. A.)2_
Val Verde's Lorenzo 30551 (A. M. G. R. A.)'..
Test
ed
Num-\
ber i Lbs.
19 I 1,004.2
35 J 1,201.6
29 1,624.6
1 Calculated by method of Wright (33).
2 American Milk Goat Record Association.
The effect of the inbreeding in general has been to lower slightly
the milk production of the inbred does in comparison with the pro-
diiction of their dams, whereas the outcrossed daughters have ex-
ceeded their dams in milk production. In the production of butter-
fat, however, as measured by the percentage of butterfat in the milk,
the inbred does did somewhat better than the outbred does. While
it would appear from these results that close inbreeding is not a good
practice for the average breeder of goats, it is to be hoped that ex-
periment stations conducting breeding experiments with milk goats,
and likewise some of the larger breeders, can practice some inbreeding
in their herds.
Much experimental work on animals and plants has shown that
inbreeding is a certain method for increasing the purity or homozy-
gosity of inherited characteristics. If accompanied by rigid selection,
good inbred strains may eventually be isolated. Individuals of these
strains, because of their greater purity for certain desirable charac-
MILK GOATS
1307
teristics, should have a greater chance to transmit these characteris-
tics when outcrossed to unrelated goats, and they may be valuable
parental material in other ways. It should be emphasized, however,
that the use of close inbreeding for animal improvement is still in
the experimental stages, and that it is not recommended for the aver-
age private breeder.
In addition to the studies on production, the New Mexico station
has presented data on the length of the gestation period, on fertility
and fecimdity, and on the sex ratio.
A total of 144 gestation periods were recorded, 115 being for does
over 18 months old and 29 for does under 18 months. The mean
Figure 3. — United States Department of Agriculture Saanen doe no. 412 with her
quadruplet kids. Quadruplets are uncommon in milk goats, only 3 sets being re-
corded in a total of 617 parturitions in the Department herd. In the herd of the New
Mexico Agricultural Experiment Station 4 sets of quadruplets have been recorded
in a total of 14-1 parturitions. Instances of a larger number of kids at one parturition
are very rare.
length of the gestation period for all does was 149.9 days, with a
range from 136 to 157 days. For the younger does the range was
from 136 to 154 days and for the older does from 139 to 157 days.
The mean for both groups was 149.9 days.
Fertility in this herd was high. From 152 matings a total of 144
conceptions was secured; 127 of these were from single services, 13
from the second, 3 from the third, and 1 from the fourth service.
From the 144 parturitions 286 kids were produced, the distribution
of single and multiple births being as follows: Single, 40; twins, 70;
triplets, 30; and quadruplets, 4. A somewhat higher proportion of
multiple births was observed for the older does. A Saanen doe with
quadruplet kids is shown in figure 3.
1308 YEARBOOK, 1937
A preponderance of males was observed, the ratio of males to
females being 115 to 100, for a total of 363 kids examined. This is
a somewhat lower proportion of males than has been reported by
other investigators.
Private Organizations Sponsori\g Improvement
Promotion of the interests of milk-goat breeders in the United
States has depended largely on various breed associations and on
State and local organizations of breeders. Through the medium of
exhibits at State and county fairs, and by advertising in various
periodicals mostly devoted to the promotion of goats, much interest
in milk goats has been created in many sections of the country.
At the present time three associations arc registering goats — the
American Milk Goat Record Association of Vincennes, Ind., the
International Dairy Goat Record Association, at Lincoln, Nebr., and
the American Goat Society, Inc., of Wa viand, N. Y. Of these, the
first mentioned is the oldest and largest. It was organized in 1903,
and by the end of October 1936 had recorded 51,118 purebred and
grade goats. The second association was organized in 1927 and had
recorded a total of 2,323 purebred goats, while the third organization
was established in 1935 and had registered 1,527 purebred animals bv
the end of October 193(3.
The American Milk Goat Record Association has established an
advanced registry and is sponsoring the testing of does for milk and
butterfat production. Its requirements for advanced registration are
comparable in some respects with those adopted by the various
organizations promoting advanced registry of dairy cattle.10 A total
of 201 females have met the requirements for advanced registry —
123 Toggenburg, 60 Saanen, 11 Nubian, and 7 native does. In 1936
the American Goat Society, Inc., established a herd-improvement
registry for the purpose of obtaining individual production on each
doe in the herds registered under this plan.
In addition to the registry associations there are many State and
local societies that are promoting the milk-goat industry in various
ways. Three papers — the Goat World, the Dairy Goat Journal, and
the American Goat Herd — are devoted primarily to sponsoring the
interests of milk-goat breeders.
Needs of the Future
Much progress has been made by some breeders of milk goats in
improving their herds. While figures are not available on the aver-
10 The advanced registry of the American Milk Goat Record Association has been divided into two
divisions, one designated as class A and the other as class U. The division known as class A is divided
iuto classes A, B, C, I), E, F, and G, depending on the age of the animal at the beginning of the test. In
order to enter a doe in (ho 10-month, or class A division, it is necessary for the owner to weigh the milk
from each individual milking and keep a proper record of the weights throughout the testing period. A
copy of this record must be forwarded to the association at the end of each month. The doo must also
bo tested for a 24-hour period each month by a representative from the State agricultural college or experi-
ment station, in order to determine the amount of fat in the milk. The testing period cannot exceed 10
months but may be for any period under this that the owner may desire, the tests commencing on the
seventh day after parturition. However, a 2-year-old doe must produce at least 52 5 pounds of fat or
1 ,300 pounds of milk during the consecutive test period in order to be admitted to advanced registry. For
each day that the doe exceeds 2 years at the beginning of the test, and up to 5 years, the required produc-
tion is increased by 0.0U7 pound of fat or 0.2 pound of milk per day. No further increase is required for
does older than 5 years. The class B, or short-time division, of the advnueed registry requires that a doe
produce an average of 10 pounds of milk during three 24-hour test periods, taken at least 30 days apart.
This record to be supervised by three disinterested persons who make sworn statements in regard to the
production. Bucks are entered in the advanced register when they have sired three advanced-registry
daughters out of three different dams.
MILK GOATS 1309
ago production of mill? goats in this country, certainly it is far below
that of the better herds and probably below the average production
of herds in. such countries as Switzerland, where the goat plays a
greater part in domestic economy than in the United States.
There can be no doubt of the need for improvement in the milk
production of goats in the United States. While it is not to be ex-
pected, that the goat will supplant the dairy cow to any great extent,
there are sections of the country where good milk goats would con-
tribute materially to the welfare of many families. The facts that a
goat can be kept where it would be impossible to keep a cow and at
the same time will supply sufficient milk for the average family, are
features that seem to make goats suitable for families of low incomes
living on small acreages in suburban districts, in mining districts,
and in other areas where a good, supply of milk is not available and
the keeping of cows is impracticable.
in addition to milk production, attention should be given to
improvement in. the fat content of the milk, to increasing the average
duration of lactation, to the improvement of fertility and the develop-
ment of strains that will breed at any season.'1 Practically no atten-
tion has been, given to these characteristics, all of which are important.
But improvement of the goat alone will not solve the problems of
the industry as a commercial business. If an industry is to grow,
it must have new or better markets for its products. Kesearch is
greatly needed to develop uses for goat products, and one of the chief
activities of breed organizations should be to encourage research in
this field. Among the problems that might well be studied are (1)
the value of goats' milk for the feeding of infants, invalids, and per-
sons allergic to cows' milk and its products, (2) its value for the
making of cheese of various types, (3) methods for the preparation of
condensed milk in order to make it more widely available, (4) the crea-
tion of a greater demand for goat meat, by advertising and the develop-
ment of new and better recipes for its preparation, and (5) studies
on the economics of production under various systems of farming.
77m? Part of the Breeder in Future Milk Goat Improvement
Future improvement in milk goats must come largely through the
efforts of breeders. Fundamental research is needed to guide breed-
ing efforts, but research of this kind will be undertaken only at the
demand, and with the support and encouragement, of breeders. In
addition, breeders can do much themselves to improve the goat.
Practices that should be of general benefit would include:
1. The keeping of more complete records on milk and butterfat
production, fertility, and fecundity of the goats in the breeding herd.
Such records are vital to breed improvement, and the germ plasm
survey conducted by the Department of Agriculture indicates that
many prominent breeders have been lax in keeping such records.
2. The development of a more extensive record-of-performance
program that will enroll the better breeders. Fortunately the foun-
J1Most goats breed only during certain months of the year, generally from September to March. This
fact provides a problem for the producer who has need for a continuous milk supply. A few investigators
have given attention to the problem. It has been suggested that perhaps the most economical solution
is the breeding of does that come in heat regularly throughout the year. To what extent such does occur
is not known but it seems probable that such strains might be developed by the application of a proper
breeding program.
1310 YEARBOOK, 1937
elation for such a program has been laid and it should be encouraged
to the fullest extent. Dairy breeders have made much progress in
the use of record-of-performance tests and goat breeders can utilize
many of these findings in the development of their own program.
3. The more extensive use of proved sires. It is well known that
sires differ greatly in their ability to transmit inherited characteristics
to their offspring. While the record of his ancestors furnishes some
information about the value of a sire, the surest way of determining
this is to study the records of his daughters. Once a sire has proved
his ability to transmit desirable characteristics, provision should be
made to use him to the fullest extent. Because of the wide distribu-
tion of goat breeders and the relatively small size of the herds, this
will prove difficult in many cases. However, the need for the use of
such sires is so great, if proper progress is to be made, that breeders
and breed associations should make every effort to develop means
whereby exchanges of such sires could be made between breeders.
4. The development of a better spirit of cooperation among breeders.
Too frequently in the past there has been a tendency for the develop-
ment of factions. This has resulted in tendencies for various groups
in the industry to be working at cross-purposes. For instance,
several breed associations have been established, each recording all
breeds of milk goats. The result has been to lower the effectiveness
of the breed associations in sponsoring breed promotion and improve-
ment. It also makes it more difficult for the breeder to record his
animals, especially if transfers from one association to the other are
desired. With the relatively small number of purebred milk goats in
the United States, one vigorous organization receiving the support
of the whole industry certainly would seem to be sufficient.
5. Finally, more consideration needs to be given to the develop-
ment of better procedures to guide breeders in the selection of breeding
animals. Much information on the basic problems of animal breed-
ing that should be of great use to goat breeders is contained in the
1936 Yearbook of Agriculture.12
The improvement of the milk goat, in common with the improve-
ment of other species of livestock, is a large task that will require
the best efforts of the breeder, the research worker, and all other
interested agencies.
GENETIC STUDIES OF THE GOAT 13
Since the improvement of goats has rested largely in the hands of
private breeders and very few research agencies have had projects
pertaining to goat husbandry in any form, genetic studies of this
species have lagged. Nevertheless, some facts concerning the genetics
of various characters have been reported, although most of the con-
clusions must be considered as tentative.
The inheritance of horns in goats has been studied by Lush (14).
Warwick (29), Addington and Cunningham (I), Asdell and Crew (3),
and Asdell and Smith (4). The evidence in each case strongly sug-
gests that the polled and horned conditions constitute a pair of
Mendelian characters, the horned condition being recessive and due
i' See particularly pp. 110-206, 831 -8B2, 907-923, unci 007-lono.
is This section is wri I ten primarily forstudents and others professionally in teresleil in genetics or breeding.
MILK GOATS 1311
to a single, recessive gene. In a few cases, however, individuals with
scnrs (imperfectly developed horns, usually without an attachment
to the bone) were observed, but the data were too few to warrant
an attempt to interpret the significance of the scurs. Muller (18)
investigated the inheritance of the multihorned condition in goats
but found that, while the character is inherited, the mode of inheritance
was com plex.
The mode of inheritance of wattles — sometimes called tassels —
lias been investigated by Asdell and Smith (4), Lush (14), and Adding-
ton and Cunningham (1). The evidence indicates that the wattled
condition is dominant over the nonwattled condition and that one
pair of genes is concerned. The exact manner of inheritance of the
bearded condition lias not been determined, but Asdell and Smith
suggest that it is a sex-limited character dominant in the male and
recessive in the female.
An inherited nervous instability of the goat has been reported
by White and Plaskett (32), Hooper (10), and Lush (IS). If suddenly
frightened or surprised, goats with this affliction become rigid and
the worst frightened usually fall. The spell usually lasts from 10
to 20 seconds. The animals recover the use of the muscles in the
fore part of the body first, and on recovery often start moving away
with the rear quarters dragging or very stiff. After being frightened
once, the goats cannot be affected again, regardless of the extent of
fright, until 20 to 30 minutes have elapsed. These goats apparently
were quite unable to jump over obstacles of ordinary height. The
mode of inheritance has not been determined.
The presence of short ears in the goat has been reported by Wassin
(8 1 ) and Kab (12). Wassin suggests th at one pair of genes is involved
and that long ears are incompletely dominant. This would account
for the three types of ears observed, the homozygous (AA) being
long, the heterozygous (Aa) intermediate, and the recessive (aa) type
being short. The short ears described by Kab, on the other hand,
were dominant. In neither case, however, was the mode of inherit-
ance definitely determined.
Much variability in color and marking occurs in the goat. The
chief colors observed are white, brown, tan, red, roan, gray, black,
fawn, and cream, but several other colors occur less frequently.
Relatively little is known concerning the mode of inheritance of the
various colors and the interactions of the genes concerned.1*
Cryptorchidism (the condition in which one or both testes fail
to descend into the scrotum) occurs quite commonly in the goat, and
Warwick (SO) and Lush, Jones, and Dameron (16) have shown that the
condition is inherited, though the exact mode of inheritance has not
boon determined, xlt least two pairs of genes appear to be involved.
Abnormalities of the reproductive system, which take the form of an
intimate mixture of male and female parts belonging to the accessory
14 Lush (14) considers thai, solid white, as found in the Saanon, is cpistatic to all colors, this being in agree-
ment with the opinion of Asdell and Smith (4).. The latter, however, suggests that there is another type of
white, a light cream, which may be duo to an extreme type of spotting. Lush suggests that there is a tend-
ency for black to be opistat ic over nonblack and for extensive white spotting to be epislatic over nonspotting.
Asdell and Smith, on the contrary, suggest that black may be the lowest term in an alleiomorphic series
of black, chocolate, fawn, and cream, the last color being dominant to all others. They suggest that brown
is episl atic to all colors of the black series and, also, of the red and tan series, with the red and tan being hypo-
static to the black series. Oray and roan appeared to be epistatic to the red and tan, and to the black series
but hypostatic to brown.
1312 YEARBOOK, 1937
sexual organs, are rather common in the goat, according to Crew (7).
wSince the abnormalities occur more frequently in some districts than in
others, and because certain individuals in successive ma tings produce
one of more of these intersexual offspring, it would seem that the
condition is inherited. Nothing has been reported on the mode of
inheritance.
Calder (6) has studied the incidence of multiple births in the goat
and believes that prolificacy is a character controlled to some extent
by genetic factors. The male appears to be equally influential with
the female in transmitting the potentialities for multiple births.
Calder suggests that most effective results will be obtained in selecting
for prolificacy if due consideration is given to the prolificacy of both
strains, and to the actual size of the litters from which the females
and males are chosen.
BIBLIOGRAPHY
(1) Addington, L. H., and Cunningham, O. C
1935. milk goat breeding. K. Mex. Agr. Expt. Sla. Bull. 229, 81 pp.,
illus.
(2) Asdell, S. A.
1935. goat research in 1934. Brit. Goat Soc. Yearbook 1935: 101,
103-104, illus.
(3) and Chew, F. A. E.
1925. THE INHERITANCE Or HORNS IN THE GOAT. Jour. Genetics 15:
367-374.
(4) ■ and Smith, A. D. Buchanan.
1928. INHERITANCE OF COLOR, BEARD, TASSELS, AND HOUNS IN THE GOAT.
Jour. Heredity 19: 425-430, illus.
(5) Brooks, H. J.
1934. THE TREND IN PRODUCTION WITH THE ADVANCE IN" LACTATION.
Brit. Goat Soc. Yearbook 1934: 25, 20, 28-29, 31, illus.
(0) Calder, A.
1928. the inheritance or multiple births. Brit. Goat Sot'. Yearbook
1928: 53-57, illus.
(7) Crew, 1<\ A. E.
1927. the genetics op sexuality in animals. 188 pp., illus. Cambridge.
(8) Cunningham, O. C, and Addington, L. H.
1936. THE EFFECT OF EARLY BREEDING UPON THE MILK ENERGY PRODUC-
TION OF GRADE AND PUREBRED TOGGENBURG GOATS. Joill.
Dairy Sci- 19: 405-409.
(9) Evans, E. I.
1934. VIRGIN ANIMALS SECRETE MINK A FT K II rNJ I'.CTIONS III' PITUITARY
hormone. U. S. Dept. Agr. Yearbook 1934: 360-303, illus.
(10) Hooper, J. J.
1916. A peculiar breed of goats. Science (n. s.) 43: 571.
(11) Jordan, W. H., and Smith, G. A.
1917. goat's milk for infant feeding. N. Y. State Agr. Expt. Sta.
Bull. 429, 20 pp., illus.
(12) Kab, E.
1934. erbliche stummelohren bei der ziege. Zuchtungskundc 9:
452-455, illus.
(13) Kupfer, M.
1928. the sexual cycle of female domesticated mammals, the
ovarian changes anj) the periodicity of oestrum i.n" cattle,
sheep, goats, nos, donkeys, and horses. Union So. Africa
Dept, Agr., Dir. Vet. Ed. and Research Kepis. 13-14: 1211-
1270, illus.
(14) Lush, J. L.
1926. INHERITANCE OF HORNS, WATTLES, AND COLOR IN GRADE TOG-
genbuhg goats. Jour. HerediU 17: 73-91, illus.
(15)
1930. "nervous''' goats. Jour. Heredity 21: 243-247, illus.
MILK GOATS 1313
(16) Lush, J. L., Jones, J. M., and Dameron, W. H.
1930. THE INHERITANCE OF CRYPTORCHIDISM IN GOATS. TeX. Agr.
Expt. Sta. Bull. 407, 23 pp., illus.
(17) Marquardt, J. C.
1936. five million goats. Rural New Yorker 115 (5351): 36, illus.
(18) MtTLLER, R.
1918. WEITERE INZUCHTVERSUCHE MIT VIELHORNIGE ZIEGEN. Arch.
Tierkeilk. Sup. 44: 198-206.
(19) Overman, O. R., and Gaines, W. L.
1933. MILK-ENERGY FORMULAS FOR VARIOUS BREEDS OF CATTLE. Joilr.
Agr. Research 48: 1109-1120, illus.
(20) Prentice, E. P.
1935. breeding profitable dairy cattle; a new source of national
wealth. 261 pp., illus. Boston and New York.
(21) Richards, I.
1921. MODERN MILK GOATS; STATUS OF THE MILK GOAT INDUSTRY . . .
271 pp., illus. Philadelphia and London.
(22) Rogers, L. A., Associates of
1935. FUNDAMENTALS OF DAIRY SCIENCE. Ed. 2, 616 pp., flluS. NOW
York.
(23) Shaw, E. L.
1935. milk goats. U. S. Dept. Agr. Farmers' Bull. 920, 32 pp., illus.
(Revised) .
(24) Smith, A. D. Buchanan.
1934. inheritance of milk yield. Brit. Goat Soc. Yearbook 1934:
95-95, illus.
(25) Thompson, G. F.
1905. the milch goats. U. S. Dept. Agr., Bur. Anim. Indus. Bull. 68,
32 pp., illus.
(26) Turner, C. W.
1936. seasonal variation in the birth rate of the milking goat in
the united states. Jour. Dairy Sci. 19: 619-622.
(27) and Reineke, E. P.
1936. a study of the involution of the mammary gland of the goat.
Mo. Agr. Expt. Sta. Research Bui. 235, 23 pp., illus.
(28) Voohhies, E. C.
1917. the milch goat in California. Calif. Agr. Expt. Sta. Bull. 285,
pp. [87]-114, illus.
(29) Warwick, B. L.
1933. inheritance of horns in angora goats. Tex. Agr. Expt. Sta.
Ann. Rept. 46: 39.
(30)
1934. INHERITANCE OF THE RIDGLING CHARACTER IN GOATS. Tex. Agr.
Expt. Sta. Ann. Rept. 47: 28-29.
(31) Wassin, B.
1928. OHRLOSIGKEIT BEI SCHAFEN UND ZIEGEN. Ztsclir. Illduktive
Abstain, u. Vererbungslehre 49: [95]-104, illus.
(32) White, G. R., and Plaskett, J.
1904. nervous, stiff-legged or "fainting" goats. Amer. Vet. Rev.
28: 556-560, illus.
(33) Wright, S.
1922. COEFFICIENTS OF INBREEDING AND RELATIONSHIP. Amer. Nat.
56: 330-338.
1311
YEARBOOK, 1937
Figure 1.
(Legend on opposite page.)
HEREDITY
IN THE DOG
W. M. DAWSON, Associate Animal
Husbandman, Animal Husbandry
Division, Bureau of Animal Industry
N.
I O OTHER animal serves so many widely different purposes or has
been so plastic in man's hands as the dog. Those characteristics by
which, dogs differ most from other domestic animals and which make
them especially useful to man are largely of a psychological nature
such as intelligence and willingness to cooperate. This can be espe-
cially appreciated by one who has watched, a trained sheep dog working
a quarter or half mile away from his master, yet obeying every signal
that his master gives.
Partly because of their original inheritance and adaptability and
partly because of the great variability that has resulted from centuries
of selection, dogs today serve man as hunters, retrievers, guards, com-
panions, aides in war, herders of livestock, police aides, guides, draft
animals, entertainers in sports and shows, subjects in medical and
scientific investigations, scavengers, fur bearers, and in case of neces-
sity as food. Many of these uses can be subdivided and doubtless
others might be given.
The range in size is so great that some animals in the largest breeds
weigh 100 times as much as other normal individuals of the smallest
breeds. An Irish. Wolfhound standing on his hind legs can often look
over the head of a tall man, while some full-grown Chihuahuas may
stand comfortably on one's outstretched palm. Not only in size but
in form, physique, temperament, aptitude, and intelligence there is
great variation. Long, short, wide, narrow, tall, squat, slender,
chunky, graceful, awkward, excitable, placid, robust, delicate, intelli-
gent, stupid, friendly, savage, affectionate, self-contained, dignified,
ridiculous, ugly, and beautiful are terms that might be aptly applied
to different breeds and individuals. Figure 1 illustrates some of the
wide variations in type.
In many of the breeds there is a so-called "standard" size, but there
also may be a small or "toy" size, and sometimes a giant size. There
arc varieties with smooth, wire-haired, curly, long, stand-off, or corded
coats.1 Some breed standards permit all colors, others certain vari-
1 A stand-oft coat is a long profuse coat with the hair standing straight out from the body as in the Pomer-
anian and Chow. A corded coat is a coat of long curly hair matted together in the form of long ropclike cords
as in the corded poodle.
Figure 1. — Variation in body form, type of coat, and color patterns as shown by some
popular breeds of dogs in the United States. A, Pointer; B, German Shepherd;
C, Toy Poodle; D, Bulldog; E, Dachshund; F, Pekingese; C, Cocker Spaniel;
H, Chow; /, Scottish Terrier; J, Fox Terrier; K, Greyhound; L, St. Bernard.
(C, D, and L by courtesy of G. Howard Walt, Inc.)
1315
1316
YEARBOOK, 1937
ations in color, and others only a single color or color pattern. Later
in this article the causes for much of this variation will be discussed.
ORIGIN AND DOMESTICATION OF THE DOG
It is certain that doglike animals existed on the earth thousands of
years ago. The origin of the dog (Canis jamiliaris) , however, is not
known. There is considerable speculation as to whether dogs origi-
nated from such present-day wild species as wolves, jackals, and
dingoes, with which they will interbreed (fig. 2), or from other forms now-
extinct
Quite probably they trace to more than one of these sources. It has
often been supposed that the fox, which has many doglike char-
acteristics, was one of the ancestors of the dog. However, few, if
any, authentic cases of successful crosses between these two species
are known,2 although
numerous unsuccess-
ful attempts to cross
them have been re-
ported. Accordingly,
it appears improb-
able that the fox has
played a very large
part in the ancestry
of our present dogs.
Students of the an-
tiquity of the dog,
Studer(57,5S),3Breuil
(7), Elliot (/5),Osborn
(46), Allen (2), von
Stephanitz (54), and
Clark (10) are agreed
that dogs were do-
mesticated before
any of the other ani-
mals, but howlong ago
they do not know.
In Europe bones of
dogs have been found
associated with the remains of men who invaded Europe at the close
of the Paleolithic or Old Stone Age, and at the beginning of the
Neolithic or New Stone Age. Since earlier remains of dogs have not
been found in Europe, apparently they were brought to that con-
tinent by the pre-Neolithic peoples and were probably already par-
tially domesticated, serving possibly as scavengers and guards and
for food. This makes it seem probable that the dog was first do-
mesticated in Asia at an even earlier date. Somewhat more recent
evidence of domestication has been left us in the form of crude
pictures carved by prehistoric man (fig. 3) showing dogs used in the
chase (8, 35).
Figure 2. — Hybrid from a German Shepherd dog and a
female wolf. (Photograph by courtesy of John Gaits
and Fachschaft fur Deutsche Schaferhunde after von
Stephanitz (54).)
1 Schmid (6S) reports a successful cross Iwtween a fox and doR by Heck, in Germany.
' Italic numbers in parentheses refer to literature cited, p. 1328.
DOGS 1317
Dogs as Farm Animals
Dogs have held an important place in agriculture and rural life for
centuries. Probably they have been most important to the American
farmer in guarding property, herding livestock, contributing to the
sport and the larder of the master when he goes hunting, helping
exterminate vermin, and as companions and pets. While it is im-
Figure 3. — Prehistoric rock tracing representing reindeer, a horse in a boat, men, and
dogs. Cut in the quartz at Massleberg, Skee Parish, Bohuslan. Height, 5 feet;
width 12 }£ feet. (Courtesy of Cassell & Co., London, after Leighton (35).)
possible to estimate the value of these services, one can hardly imagine
a cheaper or more efficient guard service for the farm than that fur-
nished by a good watchdog, and if the same animal serves in other
ways, as it often does, one can be sure that its value considerably
exceeds the cost of keeping it. The value of dogs as companions,
especially where people lead rather isolated lives, as they sometimes
do in certain agricultural districts, is often underestimated. And
what other animal gives the growing boy, either on the farm or in
the city — or the growing girl, for that matter — as good an opportunity
JUST as some outstanding advances in other scientific fields —
advances of very great value to humanity — have been made with the
help of dogs, so their use in certain fields of genetic research seems
to offer the most practical means of attacking some very important
but difficult problems, notably those connected with the inheritance
of psychological characteristics. Because they show so wide a
range of intelligence, aptitudes, and temperament, and can be
handled easily dogs appear to be better adapted to studies of this
kind, especially with our present limited methods of measurement,
than any other animal. Aside from the possibility of improving
one of our most useful animals through such studies, there is the
still more significant possibility of adding materially to knowledge
of mammalian genetics, especially the inheritance of psychological
traits — afield in which relatively little progress has been made.
1318 YEARBOOK, 1937
to learn self-control and consideration through the care and control
of his pet?
According to an old saying, there is no good flock without a good
shepherd and no good shepherd without a good dog. There are with-
out doubt some exceptions to this, but there is no doubt that a trained
herding dog is a great help and under some conditions indispensable
in handling livestock. Many farmers enjoy hunting so that good
hunting dogs are found on many farms. If one were to estimate the
{>ercentage of the 6,812,350 farms i in the United States that have at
east one dog from the sample of which he has personal knowledge,
it would certainly be very high.
PRESENT STATUS OF GENETIC RESEARCH ON THE DOG
Although dogs have been domesticated for many centuries and have
been successfully molded into many forms adapted to man's uses by
the processes of heredity and selection, most of the breeds we know
today have originated in comparatively recent time, and up to within
a few years ago there had been very little, if any, breeding work with
dogs that could be considered of a scientific nature.
However, there is a considerable store of scientific information
concerning various aspects of the dog. Anatomists, physiologists,
and psychologists have found the dog an excellent subject, especially
in connection with medical research, for studying mammalian charac-
teristics. In fact the diet, physiology, and temperament of dogs
make them indispensable for certain types of experiment. Some of
the outstanding advances in physiology, psychology, and medicine
have been made with the help of dogs, as for example the work on
conditioned reflexes by Pavlov (48) and much of the fundamental
information on artificial respiration, and the control of diabetes and
pernicious anemia (9).
In addition to the gain for humanity that has resulted from these
experiments, dogs have been used, of course, in the study of their own
disorders. The control of hookworm following the work of Hall (19)
and of distemper resulting from the investigations of Dunkin and
Laidlaw (18, 14, 80, 81,82, 83), who were provided with funds by the
Field Distemper Council in Great Britain, has been made possible by
the use of a relatively small number of dogs in the laboratory.
Although the results obtained in some of these researches indicate
that the dog would serve as an excellent subject in the study of certain
aspects of mammalian genetics, few systematic attempts have been
made to obtain information on inheritance in this animal. However,
many reports dealing with various aspects of the genetics of the dog
have been published. The characters reported in these papers will be
considered in this article in the following order: (1 ) Cytological (con-
cerned with the chromosomes in the cell), (2) psychological, (3) mor-
phological (concerned with form and structure), and (4) color.
Investigators are in disagreement as to the number of chromosomes
in the dog. Thus Malone (40) has reported the number in the body
cells as being 21 and 22 in the male and female, respectively; Minou-
chi, according to Oguma and Kakino (44), has reported 78 chromo-
somes in the body cells of both the male and the female ; Painter (47)
4 1933 census figures.
DOGS 1319
has reported the number to be about 50, probably 52; while other
investigators have found intermediate numbers {29).
Mental Characteristics and Temperament
In the study of mental characters psychologists have been able
to measure various abilities of dogs such as the speed with which
they form conditioned reflexes or immediate reactions to a given
situation constantly repeated; their powers of discrimination with
regard to visual objects and sounds of different kinds; their ability
to make delayed responses to stimuli; and their ability to solve
problems such as the opening of a box to get food or finding their
way out of a maze or labyrinth. Since most such measurements are
difficult to make accurately and require considerable time and expense,
practically no information exists on the variation in these abilities
among dogs of the various breeds and strains or on the mode of their
inheritance.
Some information has been collected regarding the inheritance of
certain aptitudes in dogs, as is shown in the appendix. For example,
both Marchlewski (41) and Whitney (64) have reported that the
aptitude for hunting with the head carried high appears to be dominant
to the aptitude for hunting with the head carried low when certain
strains or breeds of dogs are crossed. Although the list given seems
impressive, it presents information on relatively few of the great variety
of aptitudes possessed by dogs and most of the conclusions are based
on a few observations only and have not been completely confirmed.
One of the best studies of temperament in dogs and the practical
application of genetic principles to breeding dogs with superior
abilities is that of Humphrey and his associates in producing and
training dogs for leading the blind, and for police and army service,
at Fortunate Fields, Switzerland (reported by Humphrey and Warner
(22)). The tests used were largely subjective judgments by the
trainers and while it was apparently impossible for them to determine
the exact mode of inheritance of most of the characters, they were
able by assuming that certain of these characters were largely con-
trolled by a few major genes to make marked progress in producing
P ' Body Characteristics
In addition to mental traits, such body characters of the dog as
conformation, functioning of internal organs, fertility, and resistance
to disease play an important part in his usefulness. _ The _ body
characteristics that have been studied genetically are listed in the
appendix. Of particular interest in this connection is the work being
carried on in this country by Stockard (55) and his associates at the
Cornell University .Medical College on the genetics of modified
endocrine secretion and of associated form patterns — such as head
shape — among dog breeds. (See the reported findings of Stockard
and Vicari in the appendix.)
Although the color of the animal is a body character, it is so easily
differentiated from other characters that it seems best to consider it
separately. The third part of the list (p. 1 337) gives the color characters
in dogs for which information concerning the mode of inheritance has
been reported.
1320 YEARBOOK, 1937
On tho whole, where more than one investigator has reported on
the inheritance of a color factor, the results have been similar or the
differences can be reasonably well accounted for. There appear to be
marked similarities between color inheritance in dogs and that in
rodents and in other carnivora (18), which makes some of the con-
clusions appear reasonable even where the evidence from dogs them-
selves is rather scant. No cases of proved linkage have been reported.
There is, however, fairly good evidence that there are a number of
allelomorphic (alternative) series of genes that affect color in the dog.
These have been summarized briefly in table 2 in accordance with
what seems to be the best evidence available. Some genes exhibit
multiple effects, such as those caused by the gene for dominant irregu-
lar spotting, which in addition to affecting the coat color produces
defective sight and hearing, frequently a reduction in general vigor,
and sterility in the female (pp. 1333, 1936, and 1339).
Probably the greatest contribution of the science of genetics to
practical breeding has been the formulation of a definite system of
inheritance. This system furnishes the basis for a rational approach
to breeding problems. However, at present it is difficult, for several
reasons, to make specific recommendations on many practical prob-
lems confronting the dog breeder — the breeder's aims are extremely
diversified; the dogs themselves exhibit such tremendous variations;
there are not nearly enough known facts on inheritance in dogs to
solve most of the problems of practical importance; and many practical
men have not yet familiarized themselves with general genetic prin-
ciples. (The discussion of these principles in introductory articles in
this Yearbook will probably be found helpful in this connection.)
This emphasizes the need for encouraging research on inheritance in
dogs and for organizing breeders so that they can obtain information
with regard to specific problems and can at the same time contribute
to the knowledge of inheritance in dogs from their own records.
One method of encouraging improvement in the animals themselves
would be to offer prizes at dog shows on the basis of the breeding record
of an animal instead of almost wholly on the basis of its individual
appearance or performance. Genetics has very definitely shown that
in many instances the appearance of an animal is not a reliable basis
for judging its value as a breeder. Its real breeding value depends on
its ability to pass on desirable characters and combinations of desirable
characters to its descendants. Because of the effect of dominant
genes, the appearance of an animal may give no hint of the presence of
recessive genes for quite opposite characters, more or less covered up
by the dominants. Thus a short-legged dog may carry the gene for
normal legs, which would show up in some of his descendants if they
received the same recessive gene from the other parent. Similarly,
a black dog may carry the gene for liver color. (See pp. 1334 and 1337.)
Not only individual genes but the particular combination of genes
that an animal inherits also determines its appearance or performance.
Since most animals are very mixed in their inheritance, they are
capable of transmitting a large number of different combinations of
genes to their offspring. For example, a dog of intense agouti or
wild gray color without white spots may carry the genes for dilute coat
color, for nonagouti, and for piebald white spotting. When this dog
DOGS 1321
was mated with an animal of similar mixed genetic composition, one
would expect, if agouti, intense coat color, and absence of piebald
white spotting are considered to be completely dominant, 6 to get
puppies of eight different types so far as appearance is concerned,
provided enough puppies are produced: (1) Intense agouti without
white spots, (2) intense agouti with white spots, (3) intense nonagouti
without white spots, (4) dilute agouti without white spots, (5) dilute
agouti with white spots, (6) intense nonagouti with white spots,
(7) dilute nonagouti without white spots, and (8) dilute nonagouti with
white spots. These 8 types could represent as many as 27 different
combinations of genes, considering only the characters mentioned.
Examples of the effects of certain combinations of genes for color are
given in the appendix (p. 1343). In many cases there are no data on
the results to be expected from given combinations.
This illustrates the fact, well known to geneticists, that often the
only way to judge what an animal does carry in its inheritance is by a
sufficiently extensive progeny test.
Genetic studies indicate that color, type of hair, length of legs,
form of head and body, and many other characters can be transferred
from one breed to another by cross-breeding. It is undoubtedly by
cross-breeding followed by selection that much of the variation in
dogs has come about. New mutations — sudden changes in the germ
plasm, later passed on in inheritance — wore undoubtedly transmitted
to different breeds by cross-breeding and greatly increased the number
of types. The large number of types in turn allowed great leeway for
selection and the development of still different forms. Many muta-
tions are decidedly disadvantageous to the animals possessing them —
so much so that under wild or primitive conditions they may not sur-
vive. Under the conditions of domestication, however, many of the
mutant types not only survive, but may be superior for certain of
man's uses. For example, certain inherited characters possessed by
the Russian Wolfhound give him greater speed than the wolf so that
ho is useful for hunting wolves. On the other hand it is doubtful
whether the Russian Wolfhound could compete successfully with the
wolf in the wild state because he possesses certain other inherited
characters that would put him at a disadvantage, such as a less well-
developed sense of smell and a typo of intelligence that is not quite so
well adapted to self-preservation as that of the wild animal. Reports
(5, v. 1, p. 38) of dogs that have returned to the wild state — feral
dogs — indicate that their descendants are often wolflike in form.
MEASURING THE ABILITY OF DOGS IN COMPETITION
If one were to undertake a comprehensive genetic program on the
inheritance of many of the characters that make dogs useful, a system
of measurements of these characters would have to be worked out so
that accurate comparisons could be made. At the present time dogs
are used in competitive trials of various lands, out of which certain
measurements have been developed. Generally, however, these tests
are of a sporting nature and chiefly measure the ability of the animal
to win over its opponents under the particular conditions of the trial.
'Dominance probably would not be complete in all cases so that it might be possible to subdivide some
of the phenotypie classes.
138004°— 37 84
1322
YEARBOOK, 1937
Often they measure several distinct characteristics. Thus a winning
combination must generally include a strong desire on the part of the
dog to succeed, excellent morphological and psychological adaptability,
a high degree of coordination of physical and mental powers and often
a high degree of intelligence, and perfect cooperation between the dog
and his trainer or handler. While such things are often only crudely
differentiated or measured in competitive trials, nevertheless, such
trials have been a very important factor in the development of breeds
especially suited to certain types of competition. The following
brief descriptions are given to illustrate what has been done in this
connection as well as because of their general interest to dog breeders.
Track and Sled Racing
Dog racing has been on the increase in the United States since the
devising of a mechanical rabbit for the dogs to chase. The first
track using this invention was opened in 1919 in California. In 1935
meets were held in Arizona, Arkansas, California, Florida, Massa-
chusetts, Minnesota, New York, Ohio, Oregon, Pennsylvania, Texas,
and Washington. American racing records taken from the All Sports
Record Book (42) are given in tabic 1.
Table 1. — American racing rec
ords of C
rcyhounds
Distance
(mile)
Dog
Time
Place and date
!Ho
Seconds
KM
25
26%
28
■sm
38%
62%
Tulsa, Okla., 1920.
'4 .
Miami, Fla., 1927.
!4>
Karl Kelly. -
Do.1
West Jefferson, Ohio, 1931.
Hi -
Oh Boy
Miami, Fla., 1924.
% _ __.
Me --- -
Midnight Joe .
Miami, Fla., 1925.
yA
Belmont, Calif., 1932.
i t
audicap. * Futurity is 55 j
ards longer
than J4 of a milo.
These records are not quite so fast as the best time reported for
running horses on oval tracks — three-eighths of a mile in 33% seconds,
seven-sixteenths of a mile in 39 seconds, and one-half mile in 46 %
seconds. Mick the Miller, a British dog, considered the world's
fastest Greyhound, has a record of 600 yards (a little loss than three-
eighths of a mile) in 34 seconds, which compares very well with the
best running-horse record for approximately the same distance.
Perhaps a clearer idea of how fast this dog was traveling may be
gained from stating the rate as an average of 36 miles per hour for a
distance of 600 yards.
According to Menke {42), Mick the Miller is said to be the most in-
telligent of greyhounds and showed uncanny ability in getting clear
of "jams" in the running of races, thus giving him undisputed passage-
way. From 1929 to the end of 1931 he won $50,000 in purses and
numerous cups and trophies. He was 9 years old in 1935, retired and
quartered at Walton-on-Thames for breeding purposes even though
his exact ancestry was unknown. The increase of track racing in this
country has resulted in the importation of thousands of Greyhounds
DOGS 1323
from England and Ireland and the crossing of these dogs with American
Greyhounds.
Another form of racing requiring a very different type of dog is
dog-sled racing. The most famous of these races are run in Canada
and Alaska — for example, the Eastern International Dog Sled Derby
run annually over a 120-mile course at Quebec; the Hudson Dog Sled
Derby (generally called The Pas Derby) run over a 200-mile course
from The Pas, Manitoba, to Flin Flon and return; and the All- Alaska
Dog Race at Nome. Similar races have been run in New Hampshire,
in upper New York State, and from Winnipeg, Manitoba, to St. Paul,
Minn. As the races are run on scheduled dates regardless of the wea-
ther, there is considerable variation in the time required by the win-
ning teams. Thus, over the 200-mile course at The Pas Derby the time
has varied from 24 hours 51 minutes in 1922 to 37 hours in 1929.
Alaska's Borden marathons run over a course of 26 miles 385 yards,
has been won in time varying from 1 hour 50 minutes 27 seconds to 3
hours 35 minutes. Albert Campbell, a Cree Indian, drove his team of
six dogs 522 miles in 118 hours 16 seconds to win the Red River Inter-
national Derby from Winnipeg, Manitoba, to St. Paul, Minn. Rules
governing the contests vary with regard to the number of dogs allowed
per team, whether the race must be run in laps, and other points.
Because of their remarkable strength and endurance, Huskies have
been very successful in these dog-sled races. These dogs are the
result of crossing Eskimo dogs, which probably have considerable
wolf inheritance, with such breeds as Great Dane, Newfoundland, or
German Shepherd. It may well be that at least a part of their
superiority in strength and endurance is an expression of hybrid
vigor. Deerhounds have been used in recent years in crosses with
the Eskimo dogs, but though the offspring are big, rugged animals,
it is said that temperamentally they are more of a hunting-dog than
of a sled-dog type and so are not such useful draft animals as some of
the other cross-breds. Greyhounds are also said to have been tried
in crosses with the Eskimo dogs. The offspring have superior speed
but lack the ability to withstand the severe climatic conditions under
which the sled races are often run. Today it is hard to find pure
Eskimo dogs in the North as the Eskimos themselves prefer the
stronger cross-breds.
Hunting and Herding Field Trials
Field trials for dogs are now widely held in the United States and
in some other countries, notably England, to test the ability of bird
dogs such as Setters and Pointers. These trials are actual hunting
contests in which the dogs are scored by judges for their ability to
locate the birds by scent, to point in the direction of the game, to
hold the point until the hunter fires at or flushes the birds, to retrieve
the game when crippled or killed, to cover a large area both rapidly
and efficiently, and to demonstrate endurance, tractability, style, and
perseverance. Generally the competition is divided into three classes,
PuPPy> derby, and all-age, the division depending on the age of the
dog. Contestants are run either singly or in pairs.
Similar trials are also being run for Retrievers and Spaniels. In
these, the animals must work both on land and in the water and more
1324 YEARBOOK, 1937
attention is paid to retrieving the game and less to pointing. Field
trials with Foxhounds, Bloodhounds, and other types of sporting dogs,
as well as ratters, are sometimes held, and there seems to be a growing
interest in them.
One of the effects of these trials has been a decided tendency to
develop two strains within some of the breeds involved, one being
bred to meet the requirements of field trials and the other to meet
bench-show requirements of the fancier or the standard set up by the
breed association. In the first strain, mental aptitudes and physique
are stressed, and in the second, body conformation and color. A good
example of this is to be found in English Setters, in which the Llewellin
strain has been very successful in the field, while the Laverack strain
has been most noted on the bench.
The herding of sheep by dogs goes back to prehistoric times, though,
of course, organized sheep dog trials such as are held today in a number
of countries to determine the ability of the dogs in competition are of
comparatively recent origin. In Germany organized trials were held
about the beginning of the present century. In 1873 the first sheen
dog trial was held in Wales. Since the World War, these trials
have become very popular in Great Britain and are also held on a
large scale in Australia. In the United States for the last 9 years a
sheep dog contest has been held annually in New England and
exhibitions are given at a number of fairs and livestock shows.
So far the trials in the United States have been of the type held in
Great Britain. One dog is run at a time and is directed entirely with
whistles and gestures by the master. Scores are given for the manner
and style with which the dogs handle the sheep. Trials are held in a
meadow, with the sheep being liberated at one end while the dog
and shepherd enter at the other. The dog is then sent out to gather
in the sheep, which he must bring to the shepherd. Then he must
drive them through a number of hurdles and finally into a small
pen in the open field. In some contests the dog is also required to cut
out or "shed" a certain number of marked sheep from the flock.
All of this must be done within a certain time limit, without hurrying
the sheep, and always with complete obedience to the shepherd's
commands.
Practically all the dogs entered in the contests in Great Britain
or the United States are Border or Working Collies. These dogs gen-
erally have long black and white coats and are somewhat smaller than
the Collies seen at dog shows. Their heads also are somewhat broader
and shorter than those of the show Collies, which have been selected
for long, flat, narrow-type skulls. Scotch and English shepherds
train their dogs not to bite the sheep but only to bluff them, while in
Germany, where the dog must often protect the crops from the sheep,
the shepherds train the dogs to grip the sheep if necessary. Border
Collies seldom bark, which is an advantage under the conditions pre-
vailing where they ordinarily are used. In brush country, however,
a barking dog can be heard by the sheep when he cannot be seen and
is thus often more successful in his work than a quiet one. In some
countries, the sheep must be protected from wolves and other wild
animals so that large and powerful dogs are needed. Because of these
differences in requirements and training, it is not to be expected that
DOGS 1325
the more than 40 varieties of herding dogs, including such varied
breeds as the Gorman Shepherd, Aftsch&raka, Kelpi, Puli, Old English
Sheepdog, Komondor, Bundas, Riesenschnauzer, etc., can compete
satisfactorily in trials designed for the Border Collie alone.
In former years some breeds of dogs were bred to fight each other
in the pit or arena or, as in bullbaiting, to fight a bull. This kind of
competition has largely been outlawed, and the fighting breeds —
Bull Terriers, Bulldogs, and Boxers — are now kept largely as com-
panions and guards.
Some of the recent dog shows have been featuring a new type of
contest called an obedience trial in which prizes are awarded on the
obedience of each animal to a number of commands. Poodles have
been outstandingly successful in these competitions.
Dog Shows
Of the organized competitive activities connected with dogs, the
dog shows attract the most interest. In 1935 there were, according to
Menke (42), 2,760 bench shows in the United States, with 200,000
entries and 1,000,000 paid admissions. No one knows how many dogs
there are in the United States, though a rough estimate would be
between 10,000,000 and 12,000,000. There were registered with the
American Kennel Club in the single year of 1935, 72,000 dogs that were
eligible for shows.
The largest dog show in the United States, the Westminster Dog
Show held in Madison Square Garden, New York, N. Y., had a
record in 1935 of 2,837 entries with 85 breeds represented. This
was the fifty-ninth Westminster Dog Show held under the auspices
of the American Kennel Club and it drew entries from all over the
world.
As is the case with other domestic animals, the dogs that can win
highest honors in competition either in field trials or bench shows,
usually attract the breeders, and dogs that can transmit their ability
to win soon become the foundation animals of a strain or breed. Thus
the sires Gladstone and Count Noble, which produced 25 and 30 field-
trial winners, respectively, are to be found in the ancestry of most field-
type English Setters in the United States. Dog shows also have been
one of the most potent influences on breeding in the last half century.
By fostering the adoption of breed standards and the use of these in
Judging they have kept before dog breeders fairly definite aims to be
attained. They have also been a most efficient medium for advertis-
ing those animals that, in the opinion of the judges, were the best in
their respective breeds and have helped to spread information and
interest in dog breeding. The standards, of course, have often been
largely influenced by changing fashions and frequently have little or
no relation to utility.
On the whole this use of bench-show or field-trial winners as breeders
has made for progress, although the overwhelming enrphasis on indi-
vidual performance has also sometimes perpetuated and spread
through the breeds defects carried by the foundation stock. The
ideal condition for the progress of the breeds would be to place the
emphasis on breeding records, which should include all the offspring
of a given animal instead of the winners only or at best the offspring
1326 YEARBOOK, 1937
without serious defects. Thus breeders would have a progeny test
that would indicate the real genetic constitution of a given animal.
The American Kennel Club (8), under whose auspices most of the
dog shows are held, included descriptions and standards of 102 breeds
of dogs in their book Pure-Bred Dogs published in 1935. These
breeds, together with their color, size, and principal uses, for the most
part as given in Pure-Bred Dogs, have been listed in table 3. This
table clearly indicates the variety of dogs in the United States. It is
impossible, however, to give an adequate amount of detail, and for
more complete information the readers should consult the American
Kennel Club's publication.
POSSIBILITIES OF FURTHER GENETIC RESEARCH
WITH DOGS
The improvement of dogs along certain practical lines by the use of
a knowledge of inheritance appears to offer definite promise for the
future. Thus the relative number of German Shepherd dogs that arc
suitable as guides for the blind or for police or army work can be
greatly increased by means of selective breeding and the application of
genetics as has been demonstrated at Fortunate Fields {22). Also, work-
ing ability can be successfully combined to a considerable extent with
show form according to the results obtained by the same organization.
Superior hunting dogs may be bred for certain conditions as was
done by Adametz (see Iljin (25)), who crossed English Pointers to
German Pointers to produce a rapid-working dog that could stand the
heat on the steppes of Moravia.
Improved physical and disciplinary traits can probably be secured
from certain crosses. Iljin (25) states that in several regions of the
Union of Soviet Socialist Republics German Shepherd dogs and
Doberman Pinschers are crossed for that purpose.
The histories of a large number of the present breeds as given by
the American Kennel Club (3) indicate that they originated from
matings between animals of two or more breeds made purposely to
combine certain desirable characteristics in one strain.
Doubtless many abnormalities or defects, such as cryptorchidism,
cleft palate, reduced larynx, certain types of periodic eczema, etc.,
can be eradicated or controlled through breeding as indicated by the
work of Koch (28). Studies on the inheritance of resistance to infec-
tious diseases with other species of animals, as the mouse, rabbit,
guinea pig, and chicken (see Hill (20) for a review of the subject)
would indicate that it may be possible to develop strains of dogs with
high resistance to certain of the infectious diseases, such as distemper.
In addition to the improvements that might be made in the dogs
themselves, undoubtedly studies of the inheritance of various charac-
ters in dogs would aid in a better general understanding of mammalian
genetics.
That dogs have been used extensively in anatomical, physiological,
and psychological research, as already indicated, but to a very limited
extent in genetic research is probably due to a number of reasons.
(1) Research workers in the fields mentioned have been able to utilize
dogs from city pounds and cheap animals of nondescript breeding,
DOGS
1323
whereas in making a genetic analysis a large number of animals would
have to be produced from specific matings. (2) In studying the
inheritance of certain characters, notably psychological traits, for the
study of which dogs are especially good subjects, methods of measuring
many of the characters must first be perfected before genetic studies
will be very fruitful. In the last analysis, however, probably the
principal reason why less attention has been paid to genetic research
with the dog has been
the feeling that results
promising greater im-
mediate economic gain
were to be had in other
fields.
Yet within a single
species dogs show so
wide a range of intel-
ligence and tempera-
ment that they are bet-
ter adapted for studies
of the inheritance of
these characters with
the crude methods now
available than other
species in which the
differences are less
marked, such as guinea
pigs, rats, mice, rabbits,
and poultry. Dogs
also reproduce with
reasonable rapidity
and would not be so
expensive to maintain
in sufficient numbers
under laboratory con-
ditions as horses, cattle, sheep, goats, and swine. Thus the use of
dogs as subjects in certain fields of genetic research appears to offer
the most practical means of attacking certain very important problems.
The Bureau of Animal Industry has just initiated a project to studv
the inheritance of intelligence and associated characters in farm ani-
mals with especial reference to the influence of such characters upon
performance and production. Dogs are being used in the early phases
of these studies because they probably exhibit a greater range in tem-
perament and in intelligence than most animals; different breeds
have been developed for widely different purposes and some of them
have important agricultural uses.
In this project dogs of several breeds of different temperament will
be subjected to certain tests to determine the range and type of intelli-
gence and their suitability for various purposes, especially for the
herding of sheep. Crosses also will be made between breeds and simi-
lar tests will be made on the offspring of the first generation and later
generations following the cross. One of the breeds being studied is
the Puli. Four individuals of this breed (fig. 4) were recently imported
igur
4. — Puli bitch. One of four animals of this breed
recently imported by the United States Department of
Agriculture from Hungary for use in studying the in-
heritance of intelligence and related characters in ani-
mals. The Puli has the reputation of being an excep-
tionally good herding dog in its native country. The
most favored colors are white, cream, gray, and black.
Dogs weigh about 30 pounds, bitches about 25 pounds.
1328 YEARBOOK, 1937
by the Department from Hungary. These dogs are noted in their
native country for their sheep-herding ability. Studies on this breed
and its hybrids from crosses with several other breeds are now under
way.
From these experiments facts will be secured on (1) the degree to
which intelligence is inherited, (2) the manner of its inheritance, and
(3) the influence of intelligence, temperament, and certain other
psychological traits upon certain special aptitudes of the dog. The
experiments will also furnish fundamental information on the type
of temperament and psychological traits that are needed in dogs for
special purposes. Furthermore, information will be secured on the
relation of various types of temperament to such things as feed
utilization, appetite, management, and growth. The results obtained
from these experiments are expected not only to furnish information
on these functions in dogs but also to be of value in pointing the way
for further investigations of this nature with other farm animals.
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(15) Elliot, G. F. S.
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1921. CARBON TETRACHLORID FOR THE REMOVAL OF PARASITIC WORMS,
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1933. haarfarbenvererbung bei hockbeinigen terriehn. Zlichter
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(25)
(26)
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1935. NEUE PATHOGEN'S ERBFAKTORFN BEI HUNDEN. Ztschr. Induktive
Abstain, u. Vererbungslehre 70: 503-506, illus.
(29) Krallinger, H. F.
1927. die chromosomen der haustieke. Ziichtungskunde 2: [441]-466.
(30) TiAiDLAW, P. P., and Dunkin, G. W.
1926. studies in dog-distemper, hi. the nature of the virus. Jour.
Compar. Path, and Ther. 39: 222-230.
(31) and Dunkin, G. W.
1928. STUDIES IN DOG DISTEMPER. IV. THE IMMUNISATION OF FERRETS
against dog distemper. Jour. Compar. Path, and Ther. 41:
1-17.
(32) and Dunkin, G. W.
1928. STUDIES IN DOG DISTEMPER. V. THE IMMUNISATION OF DOGS.
Jour. Compar. Path.- and Ther. 41: 209-227.
(33) and Dunkin, G. W.
1931. STUDIES IN DOG DISTEMPER. VI. DOG DISTEMPER ANTISERUM.
Jour. Compar. Path, and Ther. 44: 1-25, illus.
(34) Lang, A.
1910. UBER ALTERNATIVE VERERBUNG BEI HUNDEN. Ztschr. Induktive
Abstain, u. Vererbungslehre 3: 1-33, illus.
1330 YEARBOOK, 1937
Leighton, R.
1907. the new book oi? the Doo . . . 024 pp., illus. London, Baris,
, [etc.]
Letahd, E.
1934. LES APPLICATIONS DE LA GENET1QUE A l'kLEVAGE DE8 ANIMAUX
domestiques. 12th Internatl. Vet. Cong., New York, 3:
437-449.
Little, C. C.
1914. coat color ix pointer docs . . . Jour. Heredity 5: 244-248.
1934. inheritance in toy griffons. Jour. Heredity 25: 198-200.
■ and Jones, E. E.
1919. the inheritance of coat color in great danes. Jour. Heredity
10: 309-320.
Malone, J. Y.
1918. spermatogenesis of the dog. Amer. Micros. Soc. Trans.
37: [97]-l 10, illus.
Marohlewski, T.
.1930. genetic studies on the domestic dog. Akad. Umiejetnosci
Krakow (Acad. Sci. Cracovie) Bull. Internatl. (B) 2: [117]-145,
illus.
Menke, P. G.
1936. All Sports Record Book. New York.
Mitchell, A. L.
1935. dominant dilution and other color factors in collie dogs.
Jour. Heredity 26: 425-430, illus.
Oguma, K., and Kakino, S.
1932. a revised check list of the chromosome number in verte-
brata. Jour. Genetics 26: 1239-254].
Onslow, H.
1923. THE RELATION BETWEEN URIC ACID AND ALLANTOIN EXCRETION IN
HYBRIDS OF THE DALMATIAN HOUND. BiocllCm. Jour. 17: [334]-
340, illus.
Osborn, H. F.
1936. MEN OF THE OLD STONE AGE, THEIR ENVIRONMENT, LIFE AND ART.
545 pp., illus. New York.
Painter, T. S.
1925. A COMPARATIVE STUDY OF THE CHROMOSOMES OF MAMMALS. Amer.
Nat. 59: 385-409, illus.
Pavlov, I. P.
1928. LECTURES ON CONDITIONED REFLEXES; TWENTY-FIVE YEARS OF
OBJECTIVE STUDY OF THE HIGHER NERVOUS ACTIVITIES (BE-
HAVIOUR) of animals. Transl. by W. II. Gantt, and G. Vol-
broth. 414 pp., illus. New York.
Pearson, K., Nettleship, E., and Usher, C. II.
1911-13. A MONOGRAPH ON ALBINISM IN MAN. 3 V., illus. London.
and IJsnER, C. II.
1929. albinism in dogs. Biometrika 21: 144-163, illus.
Plate, L.
1925. uber hunderkreuzungen. Verhandl. Deut. Zool. Gescll. 30:
89-91.
1930. UBER nackthunde und kreuzungent von ceylon-nacktiiund
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[227]-282, illus.
SCHMID, B.
1936. zur psyciiologik der caniden. Zentbl. Kleintierk. u. Pclztierk.
Kleinticr u. Pclztier 12 (6): 76-77.
Stephanitz, M. von.
1923. THE GERMAN SHEPHERD DOG IN WORD AND PICTURE. Amer. ed. rev.
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1932. THE GENETICS OF MODIFIED ENDOCRINE SECRETION AND FORM
patterns among dog breeds. 6th Internatl. Cong. Genetics,
Ithaca, 1932, Proc. 2: 193-194.
DOGS 1331
(56) Stockard, C. R.
1936. AN HERID1TAHY LETHAL FOR LOCALIZED MOTOR AND PREGANGLIONIC
NEURONES WITH A RESULTING PARALYSIS IN THE DOG. Amer.
Jour. Anat. 59: 1-53, illus.
(57) Studer, T.
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(58)
1905. ETUDE SUR UN NOUVEAU CIIIEN PHEHISTOFUQUE DE LA ItUSSE.
Anthropologic 16: 269-285.
(59) Tjebbes, K., and Wriedt, C.
1927. the albino factor is the samojede dog. Hereditas 10: [165]-
168.
(60) Vicari, E. M.
1932. inheritance of thyroid-size and thyroid-structure in- sex
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1927. coat color inheritance in greyhounds. Jour. Heredity 18:
513-522, illus.
(62) Whitney, L. P.
1928. the inheritance ox)' a ticking factor in hounds. Jour. Heredity
19: 499-502, Illus.
(63)
1929. heredity of the trail barking propensity in dogs. Jour.
Heredity 20: 561-562, illus.
(64)
1932. inheritance of mental aptitudes in dogs. 6th Internatl. Cong.
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(65) Wriedt, C.
1923. hvite farver iios pattedyr. Naturcn 47: 77-88, illus.
(66) — ■
1925. letale faktoren (todbringende vererbungsfaktoren). Ztschr.
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(67)
1929. acjfspaltung der sciiadelfokm des pekingesers. Ziichter 1:
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APPENDIX
Characters in Dogs, the Inheritance of Which JTas Been Studied
by Various Research Workers 6
Mental Aptitudes
Characters and breeds Investigator
High head carriage of the English Pointer appears to be Marchlewski (41) ■
dominant to low head carriage of some strains of the
German Pointers (a).7
High head carriage of bird dogs is dominant to low head Whitney (64)-
carriage of Bloodhounds and Foxhounds (a) .
Quiet style of hunting of the English Pointer appears to Marchlewski (41).
be dominant to the yelping stylo of some strains of the
German Pointer (a).
Trail barking of hounds is dominant to still trailing of Whitney (63, 64).
various breeds of mute trailers (a) .
'It must be emphasized that many of the conclusions are tentative and that the phenotypie or outward
expression of a character may in some cases differ decidedly as a result of differences in the environment or
of various combinations and interactions of the gene or genes involved.
' Letters in parentheses indicate: (a) Author's statement, no data given, (b) conclusions drawn from small
samplo, (c) studbook records.
1332
YEARBOOK, 1937
Menial Aptitudes — Continued
Characters and breeds
Water-going propensity of the Newfoundland and bird
dogs is dominant to lack of it in hounds (a).
Bird-hunting aptitude of bird dogs is imperfectly domi-
nant to lack of it in hounds and other breeds (a).
Higher grades of pointing instinct appear to be incom-
pletely dominant to lower grades in crosses of English
Pointers and German Pointers (a).
The "backing" instinct is dependent on specific genes in
crosses between English and German Pointers and
strains of the same (a) .
The active, almost nervous, temperament of the English
Pointer is incompletely dominant to the more lethargic
temperament of the German Pointer.
A factor inhibiting liveliness appears to be present in
dogs. Thus the offspring of German Shepherd X
Siberian are rarely lively. However, the situation is
complicated as shown by the fact that the offspring of
Doberman Pinscher X German Shepherd or of Dober-
man Pinscher X Airedale Terrier are often excitable (a) .
Disposition showed a tendency toward segregation in
the offspring from a cross of a very gentle and timid Old
English Sheepdog to a plavful aggressive Scotch Collie
(b).
Auditory undersensitiveness appears to be incompletely
dominant to oversensitiveness in German Shepherd
dogs. Probably more than one factor is involved.
Tactual (body) undersensitiveness appears to be incom-
pletely dominant to tactual oversensitiveness in Ger-
man Shepherd dogs. Probably more than one factor
is involved.
Both auditory and tactual sensitiveness appear to be
associated with sex. Relatively more males are under-
sensitive and more females oversensitive than would be
expected by chance.
Energy, distrust, willingness, and trailing willingness
appear to be inherited, but evidence is not conclusive
(a).
Body Characters Other than Color
Narrow pointed head of the sheep dog is dominant to the
broad dished type of the Pointer (a) .
Elongated type of head in the Greyhound is dominant to
the Bulldog and Pug types of skull formation.
Wide form of skull and lower jaw is dominant to narrow
(as studied in the German Shepherd and crosses
between the dog and the wolf) (a).
Head shape of the Boston Terrier and French Bulldog
gives intermediate head shape when crossed with
Dachshunds. Multiple factors are involved, some
dominant and some recessive (a) .
Head shape of English Bulldog is incompletely dominant
to head shape of the Basset Hound (a) .
"Briek"-shaped head of the Airedale Terrier is incom-
pletely dominant to the type of the Doberman
Pinscher (a).
Bulldog type of head is dominant to the head type of
the Doberman Pinscher (a).
Short crown is dominant to long crown (a)
Head length shows intermediate type of inheritance (a) .
Investigator
Whitney (64).
Do.
Marchlewski (41).
Do.
Adametz. (See Hi in
(26).)
Ujin
Gates (16).
Humphrey and War-
ner (22).
Do.
Do.
Do.
Marchlewski (41).
Stonhege and Wriedt.
(See Marchlewski
(41)).
II] in (25).
Stockard (65).
Do.
Iljin (25).
Do.
Do.
Do.
DOGS
1333
Body Characters Other than Color — Continued
Characters and breeds
The orbital angle 8 appears to bo controlled by at least
two factors in crosses between the German Shepherd
dog and wolf. In the T\ animals the angle is inter-
mediate but closer to the dog type.
The form of the zygomatic process and maxillary angle
(cheekbone and angle at its anterior end) appears to
be controlled by at least two factors. Crosses were
between the German Shepherd and the wolf. The
Pj animals were intermediate but closer to the wolf
type.
Rotundity of the bullae ossea or ear bladders appears
to be controlled by at least two factors in crosses be-
tween the German Shepherd dog and the wolf. The
Pi's were intermediate.
Nonribbedness of the ear bladders appears to be con-
trolled by at least two factors. Crosses between
German Shepherd dog and wolf. Fi intermediate
but closer to wolf type.
Cheekbone breadth appears to be controlled by at least
two factors. Blending type of inheritance.
Length of muzzle and head shape intermediate in off-
spring of normal-nozed Schnauzcr-Dachshund X
short-nosed Pekingese. Results from baekcrosscs
indicate that the broad skull and greatly shortened
muzzle of the Pekingese results from a single factor
(b).
Defective sight is associated with merle dilution (p. 1461)
in the homozygous condition in Collies and with
albinism in Pekingese.
Investigator
Iljin (28).
Do.
Do.
Do.
Do.
Wriedt (67).
Double nose is inherited apparently as an incomplete
dominant in Siberians, Boxers, and Boxer X Bulldog
(a).
Normal palate is a simple dominant to various types of
cleft palate frequent in dogs with short skulls. The
defect is due to a disturbance of the pituitary growth
hormone (a).
Normal larynx is dominant to reduction and narrowing
of the larynx in Skye Terriers (a).
Pitch and timbre of the voice appear to be inherited,
but there has been no analysis (a).
Yapping bark appears to be dominant to hound drawl
(a).
Normal number of teeth is dominant to missing teeth
in German Shepherds. Probably more than one
factor is involved (a).
Deafness is associated with homozygous merle dilution
in Collies and with extreme white spotting in Great
Danes and Bull Terriers.
Small car size of Alsatian appears to be dominant to
largo car size of the Pointer (a).
Triangular type of ear in English Pointer is dominant
to the larger lobed tvpe ear of the German Pointer
(a).
Hanging or pendant ear carriage appears to be incom-
pletely dominant to erect ears in Pointer X Alsatian
and Ceylon Hairless X Dachshund.
Mitchell (43); Pearson,
Nettlcship, and Usher
(49, pt. 2, pp. 460-
520).
Iljin (25).
Koch (28).
Do.
Iljin (25).
Whitney (63).
Humphrey and Warner
(22).
Nettleship,
(49); Mitchell
Pearson
Usher
(43).
Marehlewski (41).
Do.
Plate (51), Marehlewski
(41).
*The angle formed by the intersection of a. plane across the eye socket with a horizontal plane across the
top of the skull.
1334
YEARBOOK, 1937
Body Characters Other than Color — Continued
Characters and breeds
Ear carriage appears to be generally due to three allelo-
morphs with the following relationships suggested:
H" semierect, H— lop, h- erect.
H" completely dominant to H or h.
H incompletely dominant to h.
HaIl" - HaII - IIah - semierect Collie tvpe.
HH - lop.
Hh - semierect.
hh — erect.
There is also an independent semierect type of ear car-
riage as in the Russian AVolfhound, and an indepen-
dent lop-eared type recessive to erect ear. No infor-
mation is given on this last type (a) .
Erect ear carriage seems to be partly dominant to
faulty ear carriage in German Shepherds and prob-
ably depends on multiple factors (a).
Narrow chest is dominant to broad chest (a)
Development of chest is intermediate in inheritance in
crosses of English and German Pointers (a).
Dewlap in the German Pointer is dominant to lack of it
hi the English Pointer (a).
Body form in cross-breds from Doberman Pinscher X
Rottweiler is intermediate.
Body and trunk form of St. Bernard is dominant to that
of Dachshund (b).
Body and leg form showed segregation in a cross of Old
English Sheepdog with Scotch Collie (b).
Short tail or absence of tail is duo to several factors
apparently not related to sex (b).
Short tail is dominant or incompletely dominant to
long tail in Schipperkes, and Belgian or Brussels
Griffons.
Form and posture of the tail appear to bo inherited in
addition to length (a).
11 omozygous short tail is lethal
Normal tail of Dachshund is dominant to screw tail of
Boston Terrier or French Bulldog. Two factors ap-
pear to be involved (a) .
Screw tail does not appear to be linked with hull-shaped
head in crosses of the Boston Terrier or French Bull-
flog with Dachshund and in crosses of the English
Bulldog with the Basset Hound (a) .
Normal tail of the Basset Hound is a simple dominant
over screw tail of English Bulldog (a).
Normal tail is a simple dominant to screw tail in the
French Bulldog. Screw tail is apparently based on
defective functioning of the growth hormone of the
anterior lobe of the pituitary (a).
Short legs of Dachshund, Basset Hound, Scottish Ter-
rier, etc., are incompletely dominant to normal long
legs of Saluki, Bull Terrier, French Bulldog, English
Bulldog, Sehnauzer, Fox Terrier, and other normal-
legged breeds.
Catlike compact foot of the English Pointer appears to
bo incompletely dominant to open harelikc foot of
German Pointer (a).
Closed foot appears to be dominant to open foot in Ger-
man Shepherd (a).
Short foot appears to be dominant to long foot in Ger-
man Shepherd (a).
Investigator
Iljin {25).
Do.
Humphrey and Warner
(22).
Iljin (25).
Marcblewski (41).
Do.
Wriedt (67).
Lang (34).
Gates (16).
Klodnitskv and Spett
(27).
Iljin (25), Little (38).
Iljin (25).
Vilmorin. (See Wriedt
((W)); Iljin (25).
Stockard (55).
Do.
Do.
Koch (28).
Lang (34) ; Stockard
(55); Wriedt (67).
Marchlewski (41).
Humphrey and Warner
(22).
Do.
DOGS
Body Characters Other than Color — Continued
133;
Characters and breeds
Supernumerary (fifth) toe on the hind feet appears to be
inherited in various breeds. Mode of inheritance has
not been determined (a).
Short hair (S) is due to a single gene almost completely
dominant to long hair (s) in the Newfoundland X
Pointer, Belgian or Brussels Griffon, and Dachshund.
Investigator
Iljin {25).
Lang (34); Anker (4);
Iljin (25); Little (38).
Figure 5. — Haired and hairless Mexican dogs from the same litter.
(Photograph by courtesy of the Journal of Heredity, after Stockdale (1).)
Rough or wire hair (R) appears to be due to a single
gene incompletely dominant to smooth short hair (r)
in Belgian or Brussels Griffons, Dachshunds, and
Ceylon Hairless dog X Dachshund. The R series
(R—r) interacts with the »S' series (S—s) to give the
following phenotypes:
ft.S and fts = wire 7?6' = short rs = long.
In a cross of Old English Sheepdog with Scotch Collie,
type of coat showed segregation with the additional
appearance of short smooth coat. This indicates
a more complex genetic basis for the inheritance of
length of coat than shown above (b).
Plate (51); Anker (4);
Iljin (25); Little (38).
Gates (16).
1336
YEARBOOK, 1937
Investigator
[Stockdale] (1) ; Plate
(5 1, 52) ;Letard (86).
Koch (28).
Body Characters Other than Color — Continued
Characters and breeds
Hairlessness (fig. 5) is due to a single gene incompletely
dominant to normal hair in Mexican, Ceylon, Afri-
can, and Egyptian hairless dogs and Ceylon Hairless
X Dachshund. The gene appears to be lethal in the
homozygous state and to be associated with defective
teeth and often with a slender, greyhoundlike body
conformation in the heterozygous individuals.
Cryptorchidism is inherited in many breeds. Normal
descent of the testes is a simple dominant to cryptor-
chidism in breeds having pronounced head shortening
and screw tail; apparently cryptorchidism is caused
by defective functioning of the anterior lobe of the
pituitary (a).
Thyroid size is relatively larger in the offspring of Vicari (60).
Dachshund crossed to Boston Terrier than in either
parent (a).
Relative size of thyroid in the German Shepherd is in- Do.
completely dominant to relative thyroid size of the
Basset Hound (a).
Differences in structure of the thyroid found in various Do.
breeds appear to be inherited in Mendelian fashion
(a).
The greater power of destruction of uric acid with the Onslow (45) .
formation of allantoin found in most dogs appears to
be dominant to the decreased ability reported in
specimens of the Dalmatian breed (b) .
Death of certain motor and sympathetic neurones in Stockard (56).
the lumbar region of the spinal cord causing weak-
ness and paralysis of the hind legs and in the males
chronic dilation of blood vessels to the erectile tissue
appears to be caused by multiple genes. The hypoth-
esis that three dominant genes must be present in
order that the character be expressed is suggested by
Stockard. This condition was observed by Stockard
in crosses between St. Bernard and Great "Dane, and
between Bloodhound and Great Dane. It has been
reported at times in purebred St. Bernards and Great
Danes.
Estrual weakness 9 occurs as a dominant to its absence Koch (28) .
in many breeds of dogs. The defect is due to de-
ficient functioning of the follicular hormone (a) .
One rut during the year is dominant to two ruts during Iljin (86) .
the year in cross-breds from the wolf and dog (a).
A pleiotropic gene in the Dunker breed (dominant Wriedt (66).
irregular spotting) affects color, eyes, general vigor,
and the reproductive cycle in the female.
Hypertrophy of the vaginal mucosa during heat, often Koch (28).
leading to prolapse of the vagina, is probably domi-
nant to the normal condition. It is especially fre-
quent in families showing cryptorchidism and cleav-
age malformations and is apparently due to the
imperfect functioning of the follicular hormone, the
production of which is controlled by the sex hormone
of the anterior lobe of the pituitary (a) .
Inherited periodic exzema is probably a simple dominant Do.
to its absence. Indications are that it is due to a
thyroid disturbance (a) .
Tendencies toward certain diseases, as cataract, Iljin (25).
whistling asthma, several forms of epilepsy, and
recurrent inflammation of the eyes, appear to be
inherited (a).
' The lack of readiness for copulation in the presence of normal morphological estrual phenomena.
DOGS
1337
Color Inheritance
Characters and breeds
Color (C) appears to be a simple dominant to imperfect
albinism (cb) in the offspring of colored and albino
Pekingese and in the progeny from albino Pekingese X
black Pomeranians (Wright, using the data of Pear-
son, Nettlcship, and Usher). Inconsistencies in the
data are probably due to the interaction of other
genes.
White coat with dark nose and eyes of white Pomer-
anian (<;<*) appears to be a dominant allelomorph of
partial albinism (cb) (Cornaz albino, very pale grayish
coat with pale-blue eyes appearing red in some lights)
in the Pekingese (b).
The basic gene for color (C) is dominant to (cr) which
dilutes red to yellow (found in the Siberian) and to
partial albinism (cd) found in the Samoyede (a).
Intense color is incompletely dominant to a factor
causing partial albinism (nearly white coat with
grayish black nose and dark eyes) found in the
. Samoyede dog. In the heterozygous state recessive
red is reduced to pale chamois while black is not
affected (b).
Black (B) is a simple dominant to brown or liver (6) in
Pointers, Cocker Spaniels, Dachshunds, Doberman
Pinschers, Newfoundland X Pointer, and in crosses of
wolf and German Shepherd dog.
Yellow (AY), wild gray color (A) and black and tan
spotting (a') appear to form an allclomorphie scries.
A" restricts the distribution of black and is incom-
pletely dominant over a'. A" and a ■' are found in the
Belgian or Brussels Griffon (b).
Sable is dominant to nonsable in Collies. It is due to a
single gene (A") allelomorphic to the recessive bicolor
or black and tan (o ') and is in the agouti series. It is
dominant to agouti or wild gray color (A) of the
German Shepherd. Mitchell reports the following
relationships:
A" A" — clear yellow sable.
/l"a'=varics from almost a clear yellow to dark
sable apparently governed by modi-
fiers.
A = agouti.
A"a<= sable.
Dominant black and tan (^1(), wild color (.4), self-color
(a), and recessive black and tan or liver and tan spot-
ting (a ') appear to form an allelomorphic series with
dominance in the order given from crosses of Dober-
man Pinscher with a wolf, and Doberman Pinscher
crossed to wild colored German Shepherds.
Wild gray, self-color, and black and tan appear to be
present in an allelomorphic series in crosses of wolf
and German Shepherd dog with dominance in the
order given.
Dominant yellow and its allelomorph brindlc are epi-
static to all other color pigmentation except dominant
black, common in Great Danes, sheep dogs, and
certain breeds of terriers; also probably in the Bull-
dog and Mastiff, practically absent from breeds of
Russian and French origin. (In the light of other
evidence, it may be questioned whether dominant
yellow and brindlc are allelomorphs.)
138904°— 37 85 +-f
Investigator
Pearson, Nottleship,
and Usher (49);
Wright (68) ; Pearson
and Usher (50).
Dawson (data from
Pearson and Usher
(50)).
Iljin (25).
Tjcbbes and Wricdt
(59), and data from
Pearson and Usher
(50).
Lang (34); Little (87);
Barrows and Phillips
(6); Wright (68);
Anker (/,); Iljin (24,
26).
Little (38).
Mitchell (43).
Iljin (24).
Iljin (26).
MarchleWski (41).
i33a
YEARBOOK, 1937
Color Inheritance — Continued
Characters and breeds
Recessive black is hypostatic to dominant yellow but
epistatic to brown (chocolate) and recessive yellow.
It is also recessive to wild or wolf-gray color. "Occurs
in Irish Setters, Dachshunds, Liptaks, shepherd, and
pastoral dogs (b) .
Self-color (71)10 is dominant to bicolor (black and tan)
(t) in the Basset Hound and Dachshund. In com-
bination with /i=black and E-= extension the (T-l)
series gives:
BET^ self-black, BEl<= black and tan.
BeT «= self-tan, red with black nose.
Bet = red and lemon with black nose.
Ibsen states bicolor is not in the agouti series but docs
not give evidence. (In the light of other evidence
this may be questioned.)
Solid color in incompletely dominant to bicolor (black
and tan, brown and tan, red and lemon) in Cocker
Spaniels, Doberman Pinschers, Collies, Gordon Setter
X Irish. Setter.
Dominant red in dominant to black and tan in Dachs-
hunds.
Yellow or red is epistatic to black and brown in Dachs-
hunds.
Red of Irish Terrier (probably (A")) is a simple
dominant to black and tan of Fox Terrier or Welsh
Terrier.
Black and tan may be related to black in the following
three ways:
1 . The recessive factor by which it differs may
be identical with factor by which red differs
from black. A subsidiary factor is neces-
sary to modify a red into black and tan.
2. Black and tan may be due to an allelomorph
of the extension series.
3. Black and tan may bo due to a factor inde-
pendent of the extension series.
Reddish brown (Li) is epistatic to black (A) (except
AABb'- black) in Dachshunds and Ceylon Hairless
crossed to Dachshund. Plato suggests the follow-
ing:
AABB-= dark red.
AnliB and aaBB=light red.
Aalib and aaBb— yellow.
A A lib, A Abb and Aabb = black.
aabb brown (c).
Red appears to cover up the presence of agouti or "hare
coloring" in the wire-haired Dachshund (c).
Agouti is dominant to black and tan or brown and tan
in the wire-haired Dachshund (c).
The more extensive tan markings in the Gordon Setter
are partially dominant to the lesser tan markings
(a).
Dominant black is epistatic to all other types of pig-
ment formation and probably is an allel in the exten-
sion series. It is found in Pointers, Setters, Great
Danes, Spaniels, and in some of the terriers, as the
Fox Terrier (b).
Extension of black pigment (E) is dominant to restric-
tion of black pigment; i. e., yellow (e) in Pointers (c).
Investigator
Marchlewski.(4/).
Ibsen (23); Anker (4).
Barrows and Phillips
(6') ; Iljin (24) ; Mitch-
ell US).
Hagedoorn (17); Ibsen
(23); Anker U).
Hagedoorn (17); Anker
(4).
Hirschfeld (21).
Wright (68).
Plate (»1); Anker (/,).
Anker (i).
Do.
Iljin (.».■;).
Marchlewski (41).
Little (87).
1° The symbol T used by Ibsen and Anker is not the same as that used in table 2 where bicolor is placed
in the agouti series and T is used as the symbol for the ticking series.
DOGS
1339
Color Inheritance — Continued
Characters and breeds
Black (E) is dominant to brindlo (E1) and to red or fawn
(e). Brindle (E1) is dominant to red or fawn (e) in
Great Danes and Greyhounds. Little and Jones, and
Warren suggest that they form a triple allelomorphic
series (c).
Brindling appears to be dominant to the lack of it in
Irish Wolfhounds and Great Danes (c).
Black or liver is a simple dominant to red (ee) (a)
Black appears to be dominant to tan or red in the Dober-
man Pinscher.
Black and liver are dominant to recessive yellow present
in Pointers, and frequently in English Setters (a).
Dirty-white bolt, yellow-brown belt of medium inten-
sity, and bright-yellow belt in wild gray hair appear
to be determined by triple allelomorphic genes in
crosses of the wolf and German Shepherd dog. Domi-
nance tends to bo in the order given but is very weak
between the first two.
Grayish-white dappling, light-yellow dappling, red
dappling, appear to be present in an allelomorphic
series in crosses of wolf and German Shepherd dog.
Dominance is in the order given.
Intense coat color is a simple dominant to a factor dilut-
ing black coat color to blue and red to fawn or lemon
in Cocker Spaniels, Great Danes, Doberman Pin-
schers, and Greyhounds. In Greyhounds, Warren
found some evidence indicating the factor diluting red
was not the same as the one diluting black.
The rough hair gene appears to dilute the coat colors,
especially yellow, in Belgian or Brussels Griffons.
Intense pigmentation of hair, ball of foot, claws, and
skin in hairless dogs (D) is incompletely dominant
to dilute pigmentation of same (d) in crosses of the
Ceylon Hairless dog X the Dachshund.
Dominant irregular white spotting harlequin pattern,
often associated with wall eye and in extreme white
individuals with deafness, is reported to be a simple
dominant to the absence of such spotting in Cocker
Spaniels, Great Danes, Old English Sheepdogs, Dal-
matians, and possibly Bull Terriers. Though re-
ported as a dominant, most individuals affected ap-
pear to be heterozygous. Iljin reports that this
spotting pattern does not show when present in
yellow or lemon hounds.
Dominant irregular spotting (merle dilution — fig. 6)
often associated with wall eye is reported to be due
to a single gene dominant to the absence of such
spotting in the merle Collie, dappled Dachshund,
and Norwegian Dunker Hound. In the heterozygous
condition it produces irregular dark spots on a lighter
pigmented ground color. With yellow or sable ani-
mals, however, its presence is often difficult to detect
unless it has affected the eyes. In the homozygous
condition it produces pale-gray or yellow spots on a
white coat and generally defective sight and hearing.
Mitchell suggests the above pattern is produced by
the same gene as the harlequin pattern except that
in the latter case there is an independent modifying
gene which dilutes the ground color to white.
Investigator
Little and Jones (89);
Dighton (IS); War-
ren (61).
Darling and Gardner
(11); Little and Jones
(39).
Wright (68).
Iljin (H).
Marchlewski (41).
Iljin (26).
Iljin (26).
Barrows and Phillips
(6); Little and Jones
(39); Dighton (12);
Warren (61) ; Iljin
(24).
Little (38).
Plate (SI).
Pearson, Nettleship and
Usher (49); Barrows
and Phillips (6) ;
Wright (68) ; Little
and Jones (39); Wriedt
(66) ; Marchlewski
(41); Iljin (26); Hum-
phrey and Warner
(22); Mitchell (43).
Wriedt (66); Anker (4);
Mitchell (43).
1310
YEARBOOK, 1937
Collies showing the effects
of the genes J'-v for domi-
nant spotting (merle dilu-
tion): A, Normal black and
tan Collie (ti>): B, blue merle
Collie (fv), which happens
to have both eyes normal,
but often one or both eyes
will be wholly or partly of
a pale bluish-white color —
"wall-eyed"; C, merle Collie
with defective sight and
hearing (IT). Since blue
merles or sable merles are
mixed (F '»), they will not
breed true when mated
together. (Photographs by-
courtesy of the Journal of
Heredity, after Mitchell
(43).)
Figure 6.
DOGS
1341
Color Inheritance — Con tinued
Characters and breeds
Self-color (S) is dominant to piebald white spotting (s)
in hounds, sheep dogs, Doberman Pinschers, Great
Danes, Cocker Spaniels, Newfoundland X Pointer,
Ceylon HairlessX Dachshund, Airedale X Fox Terrier,
and wolf X German Shepherd dog. It appears to be
subject to modifying genes causing it to range from
a very little white on the coat to practically entirely
white animals. The lesser degrees of piebald white
spotting appear to be dominant to the greater degrees.
Haldane attributes this variation to throe allelomor-
phic factors, si, s2, and s4. Wriedt suggests »S's animals
are generally solid color except for small white mark-
ings on chest and toes.
Self-color with white on chest and toes completely dom-
inant over markings in Newfoundland X Pointer.
Dominant white .(IF) is dominant to color (w). It
occurs in the Russian Shepherd and sometimes in
the Siberian (a).
Colored coat (11°) appears to be a simple dominant to
white coat (w1) in Collies. Heterozygous animals
(W'w1) often have more prominent white markings
than those free of the factor. These white Collies
have dark eyes and nose. As a ride there is some color
on the head (a).
Tricolor is caused by a combination of black and tan
(bicolor, a') and piebald white spotting (s) in hounds
and Collies.
Pigmented point in the midst of a white area on top of the
head usually dividing the pigmented auricular regions
behaves as a dominant to the lack of it in Pointers (a).
Self-color of ear appears to be dominant to white spots
on the ear. In the heterozygous condition there are
a few white hairs on the ear (a) .
Ticking or roan (fig. 7) is a simple dominant to the lack
of it in Cocker Spaniels, Setters, Pointers, and Fox-
hounds. It does not show except on white, and heav-
ier grades appear to be dominant to the lighter grades.
Nonsilvering appears to be a simple dominant to silver-
ing in Doberman Pinscher (a).
Eye color showed segregation in a cross of a dark brown-
eyed Old English Sheepdog with a light brown-eyed
Scotch Collie with the additional appearance of "" "11
'wall
eye.'
Dark eves appear to be dominant to lighter colored ones
in Cocker Spaniels and German Shepherds (a).
Brown or yellow eyes (F) appear to be dominant to blue
eyes (y) (a).
Normal eyes (P) appear to be dominant to ruby eyes
(VT) (a). _
Wall eye is associated with merle dilution in Collies,
Old English Sheepdogs, Shetland Sheepdogs, Dap-
pled Dachshunds, and Norwegian Dunker Hounds,
and with irregular black and white spotting in har-
lequin Great Danes, Dalmatians, and Bull Terriers.
The nose is always the same color as the footpads in
Cocker Spaniels.
The colors (black, blue, red, fawn, white, brindle, or
white spotting) do not appear to be linked with sex
in Greyhounds.
None of the colors appear to be linked with sex in the
Dachshund.
Investigator
Lang (3/,) ; Wright (68)
Little and Jones (39)
Wriedt (6.5) ; Plate
(51) ; Warren (61)
Haldane (18); Mar
chlewski (41) ; Iljin
(24, 25, 26); Hirsch-
feld (21) ; Mitchell
(43).
Lang (34).
Iljin (26).
Mitchell (43).
Ibsen (23); Wright (68);
Mitchell (43).
Marchlewski (41).
Do.
Barrows and Phillips
(6'); Wright (68);
Whitney (62); Mar-
chlewski (41).
Iljin (24).
Gates (16).
Barrows and Phillips
(6)'; Humphrev and
Warner (22).
Iljin (25).
Do.
Gates (16); Pearson,
Nettleship, and Usher
(49), Anker (4);
Wriedt (65) ; Mitchell
(43).
Barrows and Phillips
(6).
Warren (61).
Anker (4).
1312
YEARBOOK, 1937
Figure 7. — Foxhounds showing the absence and presence of ticking, colored hairs
intermingled with white hairs on those portions of the body that would otherwise
be white: A, Foxhound bitch without ticking («); B, Foxhound dog with ticking (Ti).
Eight of the fifteen offspring from the above animals were ticked. (Photographs by
courtesy of the Journal of Heredity, after Whitney (62).)
DOGS
1343
Table 2. — Allelonutrphic color series in the dog '
Series
Gene
symbol
Phenotypio effect
C
C
Basic factor for color.
Cr
Dilutes red to yellow (found in Siberians) may be Ccd.
e"
Partial albinism, white coat, dark eyes and nose as in Samoyede and white Pomeranian.
C"
Partial albinism, slightly colored coat, blue eyes appearing red in reflected light, albino
Pekingese.
B
B
Factor for black.
b
Dilutes black of coat to chocolate or colTcc brown and also dilutes nose anil eye color.
A
A'
Dominant yellow or sable.
A
Wild gray, agouti.
a
Self-color, black or nonagouti.
a'
Bicolor, black and tan, liver and tan, red and yellow.
E
E<>
Dominant black.
E
Normal extension of black pigment.
ev
Partial extension of black pigment (brindle).
€
Nonextension of black pigment, red or recessive yellow.
I
I
Dirty-white belts in wild gray hair.
jm
Yellow-brown (medium intensity) belts in wild gray hair.
I
Clear-yellow (intense) broad belts in wild gray hair.
h
h
Gray-white dapples.*
il"
Light-yellow dapples.2
Red dapples.2
D
D
Intense color.
d
Dilutes black to blue and possibly red to fawn or yellow.
V
V
Dominant spotting dilutes the coat and often the eye, nose, and footpads except for
irregular pigmented areas, as in the merle Collie and harlequin Great Dane (ap-
parently effected by modifiers).
Self-color (in the absence of other genes for spotting).
V
s
S
Self or solid color.
s
Piebald white markings (there may be other allels in this series).
w
W
Dominant white in Russian Shepherd dog and sometimes in the Siberian.
w'
Colored.
w
W
Colored. ._ „
w
White coat as found in Collies (possibly is an allelomorph of S or s with a modifier).
T
T
Ticking or roaning on white (there may be other allels in this scries).
t
Lack of ticking or roaning.
Si
Si
Nonsilvering.
Si
Silvering.
Y
Y
Brown or yellow eye color.
V
Blue eye color.
P
P
Normal eye (greenish reflection).
V
Ruby eye (red reflection).
1 In general dominance within the series is in the order given. There is a divergence of opinion and lack
of certainty with regard to the existence of some of the above genes and also with regard to the allelomorphic
relationships (see list (pp. 1331-1341) and discussion in the text). The symbols have been changed in some
cases from those used by the original investigator.
2 Possibly the same as the / series; the different pheiiotypic effect may be due to different gene combi-
nations.
Formulas for Some of the Most Common Colors and Color
Patterns in Working Dogs (Homozygous Individuals) n
Genetic formula
CCAABBDDEESS
CCaaBBDDEESS
CCaabbDDEESS
CCaaBBddEESS
CCaaBBDDe*e»SS
CCaaBBDDeeSS
CCAABBDDeeSS
CCaabbDDeeSS
CCa'a'BBDDEESS
CCa'a'bbDDEESS
CCa'a'BBddEESS
CCaaBBDDEEss
CCaabbDDEEss
And generally
cdcd
w
Phenotypic appearance
Wild gray.
Black.
Liver.
Blue.
Brindle.
iYellow, black nose.
Yellow, brown, or light colored nose.
Black with tan markings.
Liver with tan markings.
Blue with tan markings.
Black with white spots.
Liver with white spots.
1 White — Thus cdcd and W are epistatio to, or cover up the
| action of the other genes given.
n From Iljin (25) with slight modifications. He included in working dogs the following breeds: Dober-
man Pinscher, German Shepherd, Airedale Terrier, Rottweiler, Giant Schnauzer, Boxer, Siberian, shep-
herd dog of southern part of the Union of Soviet Socialist Republics. Because of the phenomenon of domi-
nance, heterozygous individuals will often appear similar to homozygous ones; however, segregation may
show up among the offspring of the former. Since there are many genes affecting color, animals heterozygous
for at least some of them are quite cimmon even among purebred dogs.
1344
YEARBOOK, 1937
Tabie 3. — Color, weight, and most important uses of breeds of dogs recognized by the
American Kennel Club 1
GKOfJP 1, SPORTING DOGS
Principal colors
Weight
Broed
Males
Females
Principal uses
Wire-haired
Pointing Griff -
on.
Steel gray with chestnut
splashes. Gray white
with chestnut splashes.
Dirty white mixed with
chestnut. Never black.
White with liver, black, or
lemon markings, solid
black or liver.
Solid liver, liver and white
spotted, liver and white
spotted and ticked, liver
and white ticked.
Dead-grass color, dark
brown to faded tan.
Pounds
About 56
50-55 .
55-70.
65-75
Pounds
About 56
•15-50 _. .
45-00
55-65. ... .
60-70
60-70 .
Pointing game birds;
retrieving.
Pointing and retriev-
ing game birds;
companions.
Pointing and retriev-
ing game birds, in-
cluding ducks;
trailing; compan-
ions.
Retrieving, especial-
ly ducks.
Retrieving game,
land or water.
Do.
Short-haired Ger-
man Pointer.
Chesapeake Bay
Retriever.
Curly-coated Re-
00-70 .
60-70 ....
05-68 .
triever.
Flat-coated Re-
do
triever.
Golden Retriever.
Rich golden...
55-60
55-65
Do.
Labrador Re-
55-65
55-70
About 70
50-65...
Retrieving and gun
dogs.
Pointing and retriev-
ing game birds;
companions.
Do.
Do.
triever.
English Setter. ..
Gordon Setter
Irish Setter
Black, white and tan, black
and white, blue belton,'
lemon and white, lemon
belton, orange belton,
liver and white, liver bel-
ton, solid white.
Black with tan markings
Golden chestnut or mahog-
any red.
Liver and white or orange
and white. Often with
roan ticking.
Lemon and white, orange
and white.
Solid black, red, or liver.
Above colors with white
on chest.
Any color except red and
white, and lemon and
white.
Solid black, liver, golden
liver, mahogany red, roan,
or the above with tan over
the eyes and on cheeks,
feet, and pasterm.
Deep pure liver without
white.
Kich golden liver
50-65
About 70
40-55 . . .
(3)- -
35-50
18-24...
Brittany Spaniel.
(')---
Pointing and retriev-
ing.
Finding game, es-
pecially birds; re-
trieving.
Finding game, es-
pecially birds in
heavy cover; re-
trieving; compan-
ions.
Finding and spring-
ing game, espe-
cially birds; re-
trieving.
Finding game, es-
pecially birds; re-
trieving.
Retrieving ducks.
Finding game, es-
pecially birds in
heavy cover.
Finding game, es-
pecially birds in
rough country with
heavy cover; re-
trievers; compan-
ions.
Clumber Spaniel.
Cocker Spaniel ..
55-65
18-24
English Springer
Spaniel.
Field Spaniel
35-50
Average 42... .
35-50
Irish Water
Spaniel.
Sussex Spaniel
About 60
35-45
About 60
35-45
Welsh Springer
Spaniel.
Dark rich red and white
i
33-40
33-40...
1 For more complete descriptions and histories of the various breeds see the American Kennel Club (8)
from which most of this iniormation was taken. An approximate weight to give the reader some idea of the
size of the breed has been added, where possible, for those breeds having no official weight range in the
breed standard. Dogs of all breeds are used as companions to at least some extent, even though that use is
not listed for each breed in the table. The group classification is that used by the American Kenneli Club.
It is realized that in some respects this classification is not consistent with respect to the uses and characters
of certain breeds. However, it would be difficult to make a classification that would not be subject to similar
criticism, also the above classification appears to meet the needs of breeders fairlv well.
1 The belton color is produced by an intermingling of colored and white hairs in the coat.
8 No published weights.
DOGS
1345
Table 3. — Color, iceight, and most important uses of breeds of dogs recognized by the
American Kennel Club — Continued
GROUP 2. SPOUTING DOGS (HOUNDS)
We
ght
Breed
Principal colors
Principal uses
Males
Females
Pounds
Pounds
Afghan Hound...
Black and tan, black, golden.
About 60
About 60
Coursing jack rab-
bits; in its native
country, hunting
gazelle and leo-
pard.
Hunting foxes, rab-
Basset Hound
Generally black, tan or
white, or a combination of
25-40
25-40 _
bits, and pheas-
these.
ants; trailing in
dense cover.
Beagle
Black, tan, black and tan,
black and white, tan and
white, black and tan and
white.
(3)
W -
Hunting individual-
ly, or in packs for
hare, rabbit, and
drag hunting.
Bloodhound—
Black and tan, red and tan,
tawny, sometimes with
90
80..
Trailing criminals
and hunting for
small amounts of white.
lost persons and
articles.
Dachshund, 3
Solid red (tan) of various
5-35
5-35
Companions; hunt-
varieties-
shades, black with tan
ing rabbits; in their
smooth or
points, ehocoiate with tan
native country
short - haired;
points.
hunting badger.
wire - haired;
long-haired.
Scottish Deer-
Dark blue gray, darker and
SB-no
75-95
Hunting wolves, coy-
hound.
lighter grays, brindles,
yellow and sandy red, red
and fawn.
otes, rabbits; for-
merly for hunting
deer in Scotland;
American Fox-
Black, tan, black and tan,
50-60.. _.
50-60
companions.
Fox hunting; drag
hound.
black and whito, tan and
white, black and tan and
white, often ticked.
hunting; used
singly or in packs.
English Fox-
Black, tan, black and tan,
black and white, tan and
white, black and tan and
60-80..
60-80
Fox hunting; drag
hound.
hunting; generally
in packs.
white.
Greyhound
Black, blue, brindle, red,
65-70
60-65... _.
Coursing hare and
fawn, white and above
jack rabbits;
colors with white.
racing.
Harrier
Black, tan, black and tan,
black and white, tan and
white, black and tan and
white, sometimes of a
blue mottled color.
About 56
About 56
Hunting hare and
drag hunting.
Norwegian Elk-
Gray with black tips to the
About 60
About CO.
Hunting big game;
hound.
long covering hairs, some-
what lighter on under part
of body.
companions.
Otterhound.. ..
Blue and white, grizzle or
sandy, black and tan.
Up to 65
Up to 65
Companions; former-
ly for hunting otter
in England.
Saluki
Cream, fawn, red, grizzle
About 70
About 70
Coursing; hurdle rac-
and tan, black and tan,
ing; companion?.
whito and chestnut, tri-
color (black, white and
tan), solid black.
Whippet
Black, blue, red, white.
30-28, average
10-28, average
Racing; coursing rab-
bits; companions.
fawn, gray, brindle, and
20.
20.
combination of these with
whito.
Irish Wolfhound .
Gray, brindle, red, black,
pure white, fawn.
Minimum 120..
Minimum 120..
Running and killing
coyotes and wolves;
guards; eoin-
R us si an Wolf-
White usually predominat-
75-105
55-90
panions.
Hunting wolves;
hound.
ing marked with lemon,
tan, brindle, gray, or black.
coursing hare;
companions.
' \o published weights.
1346
YEARBOOK, 1937
Table 3. — Color, weight, and most important uses of breeds of dogs recognized by the
American Kennel Club — Continued
GROUP 3. WORKING DOGS
Breed
Alaskan Mala-
inute.
Belgian Sheep-
dog.
Bouviers de
Flandre.
Boxer ,
Brlard _._
Bull-MastifT
Collie (rough)
Collie (smooth)..
Doherman I'in-
sehor.
Eskimo.
German Shep-
herd.
Great Dane
Great Pyrenees..
Kuvasz....
Mastiff....
Newfoundland. . .
Old English
Sheepdog.
Rottweiler.
Weight
Principal colors
Woliish gray or black and
white. Caplike or mask-
like marking on face.
Long-haired variety, black.
Short-haired variety,
brindled fawn with black,
mask.
From fawn to black through
pepper and salt, gray and
brindle.
Fawn and brindle with
mask, white with black,
fawn or brindle mark-
ings.
Black, black witli some
white hairs, dark and
light gray, tawny, and
combinations of gray and
tawny.
Any shade of fawn or brindle.
Black and tan with white
frill and collar, sable with
white markings, white,
blue merle.
Black and tan with white
markings, sable with
white markings.
Black, brown, or blue with
rust-red sharply defined
markings.
Black, white, black and
white, wolf gray, blue
gray, all shades of tan or
bull and all combinations
of these colors.
Various shades of grav,
black, black and tan,
brindle, brown, white
marking permitted.
Brindled, fawn, blue, black,
harlequin.
White or principally white
with markings of badger,
gray, or tan,
Pure white ...
Silver fawn or dark fawn
brindle, with muzzle, ears,
and nose black.
Dull jet black, white and
black or bronze.
Gray, grizzle, blue or blue
merled, with or without
white markings in vary-
ing amounts.
Black with tan or brown
markings.
Males
Pounds
05-85
About S3..
m
About SO-
SO. ..
05...
05-85
Principal uses
Females
Pounds
50-70
About S3.
(?)
About 50..
GO-
ioo.
50...
About 65.
120-160..
100-125..
«-—
About 170.
140-150....
About 65-
(!)
A bout 55.
100-130.
00-115...
(»)
About 170.
110-120....
About 65..
(?)
> No published weights.
Sledge dogs; dog-sled
racing.
Herding sheep; police
and army service.
Farm dog; watchdog;
police and army
service.
Guards and watch-
dogs; police work;
companions; for-
merly dog fighting
and bull baiting.
Sheep and guard
dogs; police arid
army service.
Guards and watch-
dogs.
Herding or driving
livestock; compan-
ions.
Do.
Guards; watchdogs;
police and army
service.
Draft and pack serv-
ice, especially on
ice and snow; bunt-
ing in the Arctic.
Herding livestock;
police and army
service; watchdogs;
guides for the
blind.
Guards; companions;
originally for hunt-
ing large game.
Guards and compan-
ions; used for guard-
ing flocks and for
pack and draft
service in the Pyre-
nees Mountains.
Guards and compan-
ions.
Guards and compan-
ions; formerly for
fighting (dog fight-
ing, bull baiting,
bear baiting, etc.).
Water dogs; formerly
for carrying life
lines from stranded
vessels; guards;
companions.
Herding cattle or
sheep; watchdogs;
companions.
Driving livestock;
pullingcarts;guards;
police service.
DOGS
1347
Table 3. — Color, weight, and inost important uses of breeds of dogs recognized by the
American Kennel Club — Continued
GROUP 3. TiSOHKIXG DOGS— Continued
Weight
Breed
Principal colors
Males
Komales
Principal uses
Samovedo. ..
Pure white, white and bis-
cuit, cream.
Pepper and salt colored or
similar equal mixtures,
pure Mack or black and
tan.
Sable, black, blue, merle,
marked with varying
amounts of white and tan.
White, black, gray, with
white and black markings.
Hed, light or dark brindle,
with white markings.
Red (sable, fawn, or golden),
brindle, black and tan,
black and white, blue
merles.
Any color other than pure
white.
Pounds
About 45...
(3).
Pounds
About 45..
(3)
Watchdogs; compan-
ions; sledge dogs
and herding rein-
deer in Siberia.
Shetland Sheep-
dog.
7-10
54-04..
7-10
44-54
formerly cattle driv-
ing.
Watchdogs; sheep
herding; compan-
ions.
170-210
100-lt'O...
Welsh Corgis
(Cardigan).
18-25-
15-22
rescue work at tho
Ilospice of St. Ber-
nard.
20-24
1K-22
ions; driving cattlo.
(Pembroke).
CROUP 4. TEI1RIEKS
Airedale Terrier..
Eedlington Ter-
rier.
Border Terrier...
Bull Terrier
Head and ears Ian, except
for dark markings on each
side of Hie skull, legs up
to thighs and elbows tan;
body, black or dark grizzle.
Dark blue, blue and tan,
liver, liver and tan,
sandy, sandy and tan.
Red wheaten, grizzle and
tan, or blue and tan.
White
Cairn Terrier ! Any color except white,
dark muzzle, ears and tail
tip desirable.
Dandy Dinmont
Terrier.
Smooth and Wire-
haired Fox Ter-
Irish Terrier..
Kerry Blue Ter-
rier.
Lakeland Terrier.
Lhassa Terrier...
Pepper or mustard (dark
bluish black to light sil-
very gray or reddish
brown to pale fawn).
Predominately white, black,
tan or black and tan mark-
ings.
Bright red, red wheaten,
golden red.
Light to dark blue..
40-45.
About 41)..
Blue, blue and tan, black
and tan, red, mustard,
wheaten, grizzle and black.
Golden, sandy, honey dark
grizzle, slate, smoke parti-
color, black, white or
brown, dark tips to ears
and beard an asset.
24 1 22.
33-lSJi -| 11H-34. _
12-60; average, 12-60; average,
50. I 45.
14 '■ 13.... _
14-24 14-24.
14-18
27....
14-115
Not over 17.
About 14..
32-36
Not over 16.
About 14-..
Guards; hunting;
herding livestock;
police and array
service; compan-
ions.
Pets; formerly used
on badgers, foxes,
otter, etc.
Sporting terrier; bolt-
ing foxes.
Guards and com-
panions; formerly
for dog fighting.
Pets; killing vermin;
formerly for bolt-
ing otter, foxes, and
vermin.
Watchdogs; compan-
ions; hunting and
killing' vermin.
Watchdogs; compan-
ions; hunting and
killing vermin;
originally for bolt-
ing foxes.
Companions; hunt-
ing small game and
vermin; house
dogs; army serv-
ice.
Watchdogs; compan-
ions; hunting;
shepherd dogs.
Watchdogs; compan-
ions; hunting small
game.
Watchdogs; compan-
ions; and pets.
3 No. published weights.
1348
YEARBOOK, 1937
Table 3. — Color, weight, and most important uses of breeds of dogs recognized by the
American Kennel Club — Continued
GROUP 4. TERRIERS— Continued
Weight
IS reed
Principal colors
Manchester Ter-
rier.
Miniature
Sehnauzers.
Standard Sehnau-
zers.
Scottish Torrior.
Sealyham Terrier.
Black and tan..
Skye Terrier Dark or light blue, or gray or ]
I lawn with black points.
Welsh Terrier ' Black and tan or black griz- •
j zle and tan.
West Highland
White Terrier.
Pure while..
Pepper and salt or similar
equal mixtures, light or
dark, including red pep-
per, pure black, black and
tan.
All pepper-and-salt colored
or similar mixtures; pure
black or black and (an.
Steel or iron gray, brindled
or grizzled, black, sandy,
or wheaten.
All white or with'lemon, tan | 2
or badger markings on \
head and ears.
Principal uses
Males
; Females
Pounds
i
Po-unds
11-22
. 14-22
Pets; companions;
hunting and kill-
ing vermin.
13
-.[12
Bo.
About 28
j
. j About 28.. ...
Watchdogs; compan-
ions; hunting anil
killing vermin.
18-20
. 18-20
Pets; companions;
originally tor bolt-
ing foxes and other
vermin.
21. .j ...
_j 20 ..
Pets; companions;
originally lor hunt-
ing fox, otter, and
badger under-
• ground.
1(5-20
._! 11-18
Pets; formerly for
bolting foxes.
20.
"I 20-- -■
[
Companions; hunt-
ing fox; otter;
badger and small
game.
15 1!)
.-■ 13-15
Companions; hunt-
ing vermin.
GROUP
TOY DOGS
Chihuahua, short
and long coat-
ed.
English Toy
Spaniel:
King Charles or
Black and
Tan.
Ruby
Blenheim _
Prince Charles
or Tricolor.
Griffon:
Brussels (wire-
haired) .
Belgian (wire-
haired) .
Brabancons
(s moot h-
coated).
Italian Grey-
hound.
Japanese Spaniel..
Maltese.
Any color, solid or marked
or spashed.
Black with tan markings.
Chestnut red
White with bright rich
chestnut or ruby red
markings, evenly distrib-
uted in large patches, spot
on forehead.
White with black and tan
markings.
Reddish brown, a little
black at whiskers and chin.
Black and reddish brown
mixed black mask and
whiskers.
Reddish brown, black with
reddish brown markings.
All shades of fawn, red,
mouse, blue, cream and
white.
Black and white, all shades
of red and white.
Pure white-
Pols; ratters,
9-12.
9-12.
9-12.
9-12.
Small-sized,
not over 7;
large-sized,
not over 12.
do..
do.
Lightweight, 8
and under;
heavyweight,
over 8.
Lightweight, 7
and under;
heavyweight,
over 7.
Not over 7; un-
der 3, ideal.
Pets and
ions.
9-12.
9-12..
9-12.,
S mall-si zed,
not over 7;
large-sized,
not over 12.
do..
.do.
Lightweight, 8
and under,
heavyweight,
8 and over.
Lightweight, 7
and under;
heavyweight,
over 7.
Not over 7: un- j
der 3, ideal. I
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
compan-
DOGS
1349
Table 3. — Color, weight, and most important uses of breeds of dogs recognized by the
American Kennel Club — Continued
GROUP 5. TOY DOCS— Continued
Breed
Principal colors
Weight
Principal uses
Males
Females
Pounds
Pounds
Mexican Hairless.
Skin generally slatey gray,
sometimes mottled with
flesh-colored spots.
About 14
About 14.
Pets and compan-
ions.
Pappillorj
Unicolor— any pure color.
Two-colored— any color,
with white. Tricolored —
any two colors with white.
Less than 9
Less than 9
Do.
Pekingese
Ked, fawn, black, black and
tan, sable, bridle, white
and particolor well de-
fined, black masks and
spectacles desired.
Maximum 14...
Maximum 14...
Do.
Pinscher (minia-
Lustrous black with tan,
5-10.
5-10
Do.
ture).
rust red or lemon mark-
ings, solid yellow, solid
red or stag red, solid
brown or brown with red
or yellow markings, solid
blue or blue toned with
red or yellow markings.
Pomeranian
Black, brown, chocolate,
Lightweight,
Lightweight,
Pets; companions;
red, orange, cream, orange
not exceed-
not exceed-
watchdogs.
sable, wolf sable, beaver,
ing 7; heavy-
ing 7; heavy-
blue, white, and parti-
weight, over
weight, over
colors.
7.
7.
Pug
14-18
14-18
dark mask, black.
Toy Manchester
Jet black with rich mahog-
About 7
About 7
Pets; companions;
Terrier or Toy
any tan markings.
ratters.
Black and Tan
Terrier.
Toy Poodle
Under 12
Under 12
trick dogs.
2M-13 - -
Pets and compan-
ions.
markings.
GROUP 6, NONSPORTING DOGS
Boston Terrier.
Bulldog.
Chow Chow.
Dalmatian-
French Bulldog.
Keoshonden.
Poodle
Schipperke.
Brindle with white mark-
ings, black with white
markings.
Bed brindle, other brindles,
solid white, solid red,
fawn, or fallow, piebald.
Any clear color, usually red,
black, or blue.
Ground color, pure white
with small black or liver-
colored spots scattered
over the entire animal.
All brindle, fawn, white,
brindle and white.
Wolf gray
Any solid or even color.
Solid black.
Lightweight,
under 15; me-
diumweight,
15-20; heavy-
weight, 2(1-25.
50
55-00
35-50...:.
Lightweight,
under 22;
heavyweight,
22-28.
About 40
Large, over 20;
miniature,
12-20.
Up to 18
Lightweight,
under 15; me-
diumweight,
l.ri-20; heavy-
weight, 20-25.
40_
55-00
35-50
Lightweight,
under 22;
heavyweight,
22-28.
About 40
Large, over 20;
miniature,
12-20.
Up to 18
Companions.
Companions; guards;
formerly for dog
fighting and bull
baiting.
Companions, pets
and guard dogs.
In China as sport-
ing dogs.
Companions, sport,
formerly as coach
dogs.
Companions and
watchdogs.
Do.
Companions, pets,
trick dogs, retriev-
ing, watchdogs.
Watchdogs, ratters,
pets, and compan-
ions.
THE BREEDING
OF TURKEYS
STANLEY J. MARSDEN, Associate Poultry Husbandman,
CHARLES W. KNOX, Senior Poultry Geneticist,
Bureau of Animal Industry
J. HE chief problems of the turkey industry in its rapid development
in the past nave centered around feeding, management, and disease
control. While advances have been made in these fields there is much
yet to be learned, for new problems continue to arise. Breeding prob-
lems have received less study up to the present, partly because they
have been crowded out by these other considerations, and partly
because the turkey stocks of the United States have in a great measure
fulfilled their purpose, which was to produce a superior meat product.
PRESENT NEEDS IN TURKEY BREEDING
But this situation will not necessarily hold forever and today both
breeders and scientists are beginning to think about turkey-breeding
problems. From the standpoint of the geneticist and the practical
breeder, the desirable breeding objectives today might be summed it])
as follows:
1. The production of smaller size strains of turkeys to meet the
growing demand for a family-size bird.
2. The improvement of body type to provide a higher proportion of
edible meat, especially on legs and breast.
3. Early maturity^ in reaching market condition.
4. Higher egg production.
5. Higher fertility and hatchability.
6. Greater viability — that is, a lower mortality rate from various
causes, including disease.
Constructive breeding methods can and should play an important
part in reducing costs by considering these six objectives.
The breeding achievements of the past have consisted mainly of
the production of color variations, a substantial increase in body
weight and egg production, and a reduction in the length of legs
and neck.
At present, for reasons that will be discussed later, there is a definite
trend toward breeding a smaller, more efficient, more rapidly growing
turkey. The main objective is a live bird weighing approximately
7K to 10 pounds as a young hen or 11 to 15 pounds as a young torn, to
meet the increasing popular demand for a well-matured small turkey.
It might be thought that this demand could be supplied by selling
turkeys at an early age when they average 8 to 15 pounds in weight.
However, turkeys at this weight are continuing their rapid growth
and they have too much "framework" and too little flesh. The real
1350
TURKEYS
1351
object in breeding is to develop a small turkey that will be as plump
and well grown as present-day turkeys are at Thanksgiving or Christ-
mas time. A young torn of the small type is shown in figure 1.
The mortality of growing turkeys is a pressing problem and it is
one that the breeder can materially assist in solving. Turkev breeders,
especially those that ,___ ^_ __
trap-nest their stock,
can decrease these
losses to a consider-
able extent by breed-
ing from large fami-
lies and from families
whose progeny have
had comparati vely
little mortality.
Egg production is
an important factor
in determining profit
or loss in turkey-breed-
ing work. Turkey
eggs are sold for hatch-
ing purposes by the
producer for 10 to 50
cents each, depending
on locality and breed-
ing. Hence any in-
crease in egg produc-
tion will help profits
considerably because
it results in lowering
the overhead and feed costs of producing hatching eggs. In addition,
turkeys are seasonal producers of eggs. They lay at a fair rate in the
Northern and Central States from about the latter part of March to
Figure 1. — A young small-type lurkey torn, the second-
generation product of a Bronze-White Holland cross. At
24 weeks of age this bird weighed 13.5 pounds, had a
hroad well-meated breast, and graded U. S. Prime. His
keel measured 6.2 inches long and his shank 7.1 inches.
NOTABLE progress, based on scientific research, has been made in
controlling that major menace to turkey groiving, the blackhead
disease. Less attention has been paid to breeding problems. Today
the turkey industry would gain by a breeding program based on
production records, pedigrees, and progeny testing, like that which
has meant so much to progressive breeders of chickens. There is a
great need for turkey breeders willing to initiate trap-nesting and
pedigreeing, and possessed of the knowledge necessary to isolate
superior families and breed from them. State and Federal stations
might well lead the way by developing strains notable for certain
characteristics of major importance.
1352 YEARBOOK. 1937
about the first of July. The use of electric lights has helped in getting
birds to start laying in January, so that the laying season is extended to
approximately 6 months. However, egg production in commercial
quantities is still confined to about 6 months of the year, and this means
that fresh-killed roasting turkeys must also be a seasonal product unless
turkeys can be bred to lay throughout the year. This situation is
partially remedied by cold storage, which makes a limited supply of
frozen turkeys available at times when there is no fresh stock and
Figure 2. — Trap-nesting — the first step in the pedigree hreeding of turkeys.
permits a large turkey crop to be marketed in the fall in an orderly
manner without a serious price depression.
The greatest drawback to breeding for high egg production and the
other desirable characteristics is the lack of a program based on produc-
tion records, pedigrees, and progeny testing. Such a program has
meant much to progressive breeders of chickens. Here the State and
Federal experiment stations can lead the way by developing strains of
high-producing turkeys with good viability, "quick maturity, and good
market quality. The greatest need of the industry today is for a
number of breeders who are informed concerning the practices in-
volved in selection and breeding and who are willing to initiate trap-
nesting and pedigreeing and, on the basis of the information so
obtained, to isolate superior families and breed from them. This
is an essential step in the production of a superior strain. Two of
the steps involved in the pedigree breeding of turkeys are shown in
figures 2 and 3.
TURKEYS
1353
THE STATUS OF TURKEY GROWING
AS AN INDUSTRY
Turkey raising has been increasing since about 1920 in the United
States and now ranks as a 50,000,000-dollar industry. The interest in
turkey raising has increased rapidly since that time. It was stimu-
lated by a better knowledge of feeding and more effective control of
the disease known as blackhead. The annual loss due to blackhead
still amounts to ap-
proximately $5,000,-
000 a year, or 10 per-
cent of the total
gross income. In the
past, often entire
flocks of young turkeys
were lost from this
disease.
On January 1, 1920,
the census showed
3,627,028 turkeys on
670,834 farms held as
breeders after the
marketing season.
On January 1, 1935,
the number had in-
creased to 5,381,912
On 676 114 farms F,@lre ■?-— The final step in ihe pcdigrceing of turkey
which is 9 9 percent Of P°u,t8— handing the birds as they are taken from the
all the farms in the pedigree baskets.
United States. The leading States according to the number of
turkeys kept were Texas, California, Minnesota, North Dakota, and
Oklahoma.
The 1930 census was the first to record the number of turkeys
raised rather than the number on farms on January 1. According to
tlus census, there were 16,794,485 turkeys raised in the United States,
most of them as a side line to other farm enterprises. The distribution
and number of turkeys raised on farms in 1929 is indicated in figure 4.
The number of turkeys raised in 1936 has been estimated by the Buretfu
of Agricultural Economics to exceed 20,000,000 — an increase of at least
20 percent over the 1930 figures. There was little increase, however,
in the number of farms keeping turkeys. In some localities, turkey
raising has reached such proportions as to be a major full-time enter-
prise, and a great many commercial flocks are large enough to demand
the time of one or more persons throughout the year. The largest
turkey farm was reported to have produced approximately 50,000
turkeys in 1 year.
New Opportunities Through the Control of Blackhead
From a production standpoint, the opportunities in commercial
turkey raising are more promising now than formerly, largely because
of improved methods of management that aid in the control of black-
head and other filth-borne diseases.
138904"— 37 8(i
1354
YEARBOOK, 1937
Beginning late in the nineteenth century, blackhead invaded one
district after another, traveling from east to west with the extension
of the turkey industry, until nearly all of the turkey-growing areas
became infested with it. It was this disease that ruined turkey
growing in the East and Midwest and by 1920 threatened to ruin it
everywhere. In the early eighties production per year amounted to
numb:
0
R OF TURKEYS
HOUSAN0S)
s
OVER J
,000-
,oco
2,000
Wffii
S00 -
— 9 99
^^
300
- «-99
FTTTT71
CZ3
ICO . — 299
.CSS Th*SIC0
Figure I. — Number of turkeys raised, by Stales, in 1929.
one bird for the average American family of about 5 persons, but by
1920 this had been reduced to approximately one bird for 15 persons.
Since that time more adequate methods of controlling blackhead have
been largely responsible for the increase to approximately one turkey
for 6.5 persons. The new knowledge of sanitation and management
as it affects the control of blackhead has meant a gradual return of
turkey production to the East and Midwest and its firm establish-
ment on a more profitable basis in all sections of the country except
the Southeastern States.
MODERN TURKEYS AND THEIR
WILD ANCESTORS
Turkeys are now classified by zoologists as a separate family, Melea-
grididae, of the order Galliformes, or fowllike birds. In this family
there are two genera now living — Agriocharis, the ocellated turkey of
Yucatan (fig. 5), and Meleagris, the North American or common
turkey. These genera contain only one species each.
The ocellated or Yucatan turkey (Agriocharis ocellata) is confined
to the Yucatan Peninsula of Mexico and the adjoining territory,
where it dwells in the tropical forests. Its flesh is considered a delicacy.
It is smaller than the common turkey, lacks the breast tuft, is brighter
colored, has two fleshy appendages on the head instead of one, and has
eyed or ocellated tail feathers, from which it takes its name. So far as
TURKEYS
1355
is known, it lias never been domesticated although natural crossing
with the common turkey has been reported. In striking beauty the
plumage of the ocellated turkey rivals that of the peacock. The
plumage pattern is similar to that of the Bronze turkey although the
colors are different.
The general effect is
green and black with
a coppery red irides-
cence. The large wing
feathers of the male are
distinctly barred, al-
most exactly as in the
Bronze, while those of
the female are indis-
tinctly barred. The
head and neck of the
ocellated turkey are
described as blue,
studded with orange
warts. The eggs are
brown and spotted
like those of Meleagris
but smaller.
Five subspecies
(races or varieties) of
North American wild
turkeys have been de-
scribed. They interbreed freely with each other and with domesti-
cated turkeys. Table 1 contains a brief description of these subspecies.
Figure 5. — The oceNaled turkey
(male).
(Agriocharii ocsllata)
Table 1. — Brief description of ISorth American nild turkeys
Subspecies
Mtlrmiris galtopavo gal-
lopapo Linnaeus, the
Mexican turkey.
M. galtopavo sitventris
Vieillot, the eastern
turkey.
M. galtopavo osceota
.Scott, the Florida tur-
key.
A/. Qalloptiw intermedia
Sennett, the Rio
Grande turkey.
M. galtopavo merriami
Nelson, MerrianTs
turkey.
Original range
Central Mexico.
Eastern Cnited States, except-
ing southern Florida, to the
western and northern limits
of the species as described
above.
Florida, at least as far north :is
Gainesville.
Middle-north Texas to north-
eastern Coahuila, Nueva
Leon, and Tamaulipas.
The mountains of southern
Colorado. Arizona, New
Mexico, western Texas,
northern Sonora, and Chi-
huahua.
Color description
Similar to the Bronze variety but lacks t lie
distinct tail penciling and the heavy-copper-
colored bronzing. The terminal edgings are
almost white.
Similar to the Bronze but lacks the heavy
copper-colored bronzing and the pure white
terminal edgings. The latter are dark chest-
nut or iodine color in silvestris.
Closely resembles xitvestris but is distinguish-
able from it by the white bars of the large
wing feathers, which, in osceota, are much
narrower than the black bars and do not cross
the shaft of the feather. In all other wild
varieties and in the Bronze and Karragan-
sett, the white bars are as wide as or wider
than the black ones and extend completely
across the feathers.
Resembles stlveslris, but its terminal edgings are
light chestnut or cinnamon and its back-
feathers present a decidedly blackish appear-
ance.
Resembles silveslris but the terminal edgings
are creamy to bufTy white.
1356
YEARBOOK, 1937
The North American wild turkey (Meleagris gallopavo, fig. 6)
formerly ranged over all of Mexico except the extreme southern and
western parts; over southern Ontario, Canada; and over the United
States south and east of a line extending from south to north through
western Arizona, northeast diagonally across Colorado and Nebraska
to include a small portion of southeastern South Dakota, east across
Figure 6. — A flock of wild turkeys at the National Agricultural Research Center.
Crosses are being made of the wild on the domestic varieties.
northern Iowa, southern Wisconsin, southern Michigan, northern New
York, northern Vermont, northern New Hampshire, and southern
Maine.
Wild turkeys, principally the eastern turkey, are now bred to some
extent on game farms, both public and private.
Varieties of Domesticated American Turkeys
The turkey, the Muscovy duck, and the Canada (gray) goose
constitute the contribution of the Western Hemisphere to the list of
species of poidtry. At the time North America was discovered, the
wild turkey was found in large numbers and, in some instances, had
been domesticated by the natives. From the meager historical data
available it appears that turkeys were first taken to Spain in 1498.
The sources of these and later importations to Europe were turkeys
domesticated by the natives of Mexico and Central America. All
these turkeys apparently belonged to the Mexican subspecies of the
North American turkey. From Spain turkeys were taken to other
European countries, being introduced into England between 1524
and 1541. Several European varieties were developed, notably the
Cambridgeshire Bronze and the Norfolk Black. From Europe and
North America, turkeys were exported to all parts of the civilized
TURKEYS
1357
world. They are now raised in Europe, North America, South
America, South Africa, Australia, the Philippines, and Hawaii.
After the United States was settled, it appears that the first domes-
ticated turkeys to be raised came not from the native wild stock, but
from the domesticated turkeys of Europe. These birds were probably
all of the Bronze color pattern, although some Blacks may have been
included. For a con-
siderable time no seri-
ous attempts were
made to domesticate
the native wild tur-
keys, but finally early
in the nineteenth cen-
tury turkey breeders
began to cross the
domesticated stock
with the wild.
About 1830^0, in
the Narragansett Bay
district of Rhode
Island there was de-
veloped a local variety
which was the fore-
runner of the modern
Narragansett (fig. 7)
and Bronze (fig. 8)
varieties. About 1860
the first superior strain
of Bronze turkeys
came into prominence
and this variety was
described in the first (1871) American Standard of Perfection.
The development of the Narragansett and White Holland varieties
appears to have paralleled approximately that of the Bronze. A color
standard for the Narragansett was published in 1874, along with stand-
ard descriptions for the Slate, Black, and Buff varieties. The last-
named variety never became popular and was dropped from the
standard in 1915.
The White Holland was admitted to the standard in 1878 and the
Bourbon Red about 1909. Authentic information concerning the
origin of the Slate and Buff varieties appears to be lacking. The
White Holland variety originated as far as is known in North America,
not in the Netherlands, and was developed from white mutations
appearing in Bronze flocks. The Black turkey is an old variety that
appears to have been developed in Europe, although some strains
may have been developed independently in North America. The
Bourbon Red had its origin in Bourbon County, Ky., and is the
newest of the standard varieties.
According to the American Standard of Perfection all standard-
bred turkeys are now classified as one breed, which is subdivided into
varieties. The standard varieties all have the same shape and, except
for the Bronze, which is a little heavier than the others, they are all
lijitire 7. — A Narragansett hen showing typical mark-
ings. Wild, Bronze, and ocellated turkeys have the
same general pattern although the colors arc different.
1358
YEARBOOK, 1937
the same size. They are differentiated only by plumage color, and
one variety is as good as another for commercial turkey production.
However, there is considerable variation within each variety, so that
the selection of a good strain is more important, from the standpoint
of economical production, than the selection of a variety. Six stand-
Figure 8. — A farm breeding unit of Bronze turkeys.
ard varieties of domesticated turkeys arp now bred in the United
States. The data in tables 2 and 3 show some of the characteristics
of these varieties.
Table 2. — Standard Heights of the six standard varieties of American turkeys1
Variety
Adult toin
Yearling
torn
Young torn
Yearling
and adult
ben
Young hen
Pounds
36
33
Pounds
33
30
Pounds
25
23
Pounds
20
18
Pounds
White Holland, Narragansett, Bourbon
Red, Black, and Slate
14
1 The weights shown are for young turkeys 8 to 12 months of age, for yearlings 12 to 24 months of age,
and for adults 24 months of age or older. Actually, very few flocks of turkeys attain standard weights.
Table 3. — Color of the six standard varieties of American turkeys
Variety
Plumage color
Bronze.
Narragansett.
White Holland
Bourbon Red..
Black
Slate
Ground color is dull black but the exposed surfaces
of the feathers are glossed with rich iridescent red
green on the fore part of the body and with a brilliant
copper-colored bronzing edged with black on the
rear half. On the tail, tail coverts, and sides there is,
in addition, a terminal edging of white, which also
appears on the breast feathers of the female. Main
tail feathers and tail coverts are distinctly penciled,
medium brown and black.
The plumage pattern resembles that of the Bronze,
but there is no red-green sheen and no bronzing.
The Narragansett colors are metallic black with
light steel-gray edging bordered in certain sections
by a narrow black band on the ends of the feathers;
main tail feathers and tail coverts distinctly pen-
ciled, light brown and black.
White in all sections _ _
Dark brownish red with white wings. The breast
feathers have narrow black tips which, in the females,
are bordered with white. The tail is white with an
indistinct reddish bar near the end.
Black in all sections
Slate color in all sections
Shank color
Blackish in young birds,
pinkish in adults.
Blackish salmon in
young birds; deep sal-
mon in adults.
Pinkish white.
Reddish brown in young
birds; reddish pink in
adults.
Slate black in young
birds; pink in adults.
Pink
TURKEYS 1359
Past Work in Breeding
Even when raised in captivity and given every opportunity to make
maximum growth, wild turkeys are smaller than their domesticated
relatives. According to reliable observations, young North American
wild turkey toms, when in good condition, in December and January
average approximately 12 pounds in live weight and the young hens
about 8 pounds. The adult wild males usually weigh from 19 to 22
pounds and in rare instances attain a weight of 33 pounds when fat.
When grown in captivity under favorable conditions, the live weights
of wild turkeys are somewhat greater than those mentioned. How-
ever, there is a decided contrast between the weights commonly
attained by strains of Bronze turkeys and the much smaller weights
attained by wild turkeys even when they are raised under similar
conditions. Egg production in the better strains of modern turkeys
has been increased substantially over that of the wild turkey. Prog-
ress in breeding for plumage color is evident by the variety of colors
and patterns in the domestic birds. Some improvement in type has
also been effected. The wild turkey has a rather shallow body, a long
neck, a slender head, and long legs. The breeders of domesticated
turkeys have developed a larger bird with a deeper body, shorter legs
and neck, and heavier fleshing except over the breast, where the wild
turkey is probably the equal of the domesticated bird.
Improvements made have been few and slow and thus the good
qualities of the original stock have not been sacrificed. For example,
the eggs laid by domesticated turkeys are as fertile and hatch fully as
well as those laid by wild turkeys, and modern strains of turkeys are
as resistant to disease as the wild type. Rate of maturity to market
condition has been little influenced by domestication.
Comparatively little inbreeding or cross-breeding has been practiced
in turkey breeding, except by a very few breeders who have developed
distinctive strains or new varieties.
Private breeders have been responsible for the development of the
modern turkey in all its beauty and usefulness. However, there is no
accurate, detailed history of breed development and there has never
been a pedigree-recording system for turkeys similar to the herdbook
used with other animals. Such evidence as there is has been summed
up in the preceding paragraphs.
Today the Bronze variety predominates to an overwhelming extent.
Narragansctts, White Hollands, and Bourbon Reds are fairly common
and appear to be gaining in popularity. The Black variety is less
common although it too is probably gaining in favor. The Slate
turkey may be classified as rare and the wild turkey as rare except on
game farms.
MARKET TRENDS AND THEIR RELATION TO BREEDING
So far turkeys have been produced almost exclusively for roasting
purposes and marketed between 6 and 8 months of age. Turkey
broilers or fryers have not been produced in significant numbers and
there is little reason to believe that they will ever be a factor in the
turkey industry since smaller types of poultry fulfill this need. Tur-
key capons have been successfully produced but have not met with
1360
YEARBOOK, 1937
special favor on the markets. Until they do, the extra cost of pro-
duction will not be justified. Turkey eggs, although palatable and
suitable for cooking, do not possess the delicacy of flavor and fineness
of texture characteristic of chicken eggs. The profitable production
Wm mfw
E279d ja* EZ793
f
Figure 9. — Illustrating body type in dressed turkeys. A, Two young Black loins.
No. 2798, on the left, when killed at the age of 32 weeks, weighed 22.6 pounds
(dressed), had a narrow poorly ineated breast, a keel measuring 8.2 inches long
and a shank 8.1 inches long and produced 3.9 pounds of breast meat. No. 2793,
on its right weighed 22.3 pounds, had a broad well-meated breast, a keel bone
measuring 7.5 inches in length, and a shank 8.3 inches long, and produced 4.1
pounds of breast meat. It is desirable to have a broad well-fleshed breast. The
keel should be as long as the shank or longer. (Length of shank is distance be-
tween rear of hock joint and the ball of the foot.) B, Side view, no. 2798 on left,
no. 2793 on right.
of market eggs from turkeys seems highly improbable even as a side-
line enterprise for the turkey grower.
According to various observers, most but not all larger eating
establishments and individuals buying for large dinner groups prefer
turkeys weighing more than 15 pounds (dressed) while most of the
smaller places and American housewives in general prefer dressed
birds weighing less than 15 pounds. This preference for small turkeys
by what is now the majority of consumers has increased the demand
for hens and small toms.
Accurate estimates of the average weights at which turkeys are
marketed throughout the country are not available, but the average
TURKEYS 1361
for young hens probably ranges, in different producing areas, between
9 to 12 H pounds live weight and 8 to 11% pounds dressed weight
(blood and feathers removed). The average for young toms probably
ranges between 15 to 21% pounds live weight and 13% to 19% pounds
dressed weight. In some producing areas where large stock and good
feeding methods are used, the average body weight will be larger than
in other sections. A few years ago the average body weight of turkeys
was smaller than at the present time, but the advent of commercial
turkey raising with better feeding methods and stock bred, for large
size has increased the average weights. Standardbred young Bronze
torn turkeys raised on full feed will average 18 to 19 % pounds dressed,
and young hens 1.0% to 11% pounds, when marketed at the age of 26
to 28 weeks. Birds from strains of extra large turkeys may exceed
these weights by 25 percent or more. Figure 9 A and B illustrates
body types in dressed turkeys.
The present demand for smaller turkeys appears to be based on
sound economics — the fitting of the dressed turkey unit to the needs
of two great groups of consumers, the small-scale vendor of cooked
turkey meat and the average family. For largo family groups and
for hotels and restaurants, the large turkey is in demand, as large
toms dress out better than small toms and are fully as palatable. At
the present time, the market receipts of large turkeys are slightly in
excess of the demand, resulting in a price differential of % to 4 cents
per pound in favor of hen turkeys and small toms. Unless the de-
mand changes, which appears unlikely, future breeding operations in
turkey production should be in the direction of smaller turkeys.
RESEARCH IN TURKEY BREEDING
There has been little breeding research with turkeys. One draw-
back has been the lack of sufficient funds for this purpose; a lack of
adequately trained personnel with the proper interest in this aspect
of poultry production; and third, the susceptibility of turkeys to black-
head— but this last drawback is being rapidly overcome.
A brief description of the results of scientific investigations to date
follows and a list of references is included at the end of this article.
Work of State Experiment Stations
Except for matings to replenish flocks, turkey-breeding work has
not been carried on extensively by the State experiment stations,
though a few have initiated projects in the past or have some work
under way at the present time.
Studies on the inheritance of plumage color have been limited and
only a few individuals were used in the experiments from which con-
clusions were drawn. Some of the more important findings may be
summed up as follows: (1) Black plumage color is imperfectly dom-
inant to the bronze plumage pattern and imperfectly epistatic l
to the Narragansett plumage patterns and red plumage color. (2)
Red plumage color and Narragansett plumage pattern are epistatic
to the bronze plumage pattern. (3) The factor for slate plumage
color is a dominant dilution factor affecting the bronze and black
'Characterized by the dominant action of a gene over another gene situated on a different chromosome or
at a different place on the same chromosome.
1362 YEARBOOK, 1937
plumage patterns to produce slate-colored turkeys, or red plumage to
produce slate-red turkeys. (4) The factor providing for the presence of
plumage color is dominant to the absence of pigmentation of plumage.
When allowed to express itself, the recessive factor produces a white
bird that has brown eyes because this particular factor affects plumage
color only and does not affect eye color. All white birds, therefore,
carry the plumage pattern or color for bronze, Narragansett, black,
or red but do not show any of these patterns or colors unless they arc
crossed with colored turkeys. However, when mated together, these
white turkeys always produce white offspring. (5) Buff-colored
turkeys may be produced by first crossing black turkeys with rod
ones. The resulting rusty black offspring are then crossed back to
the red turkeys, which results in progeny having four types of plumage
color — rusty black, Bourbon Red, bronze red, and buff. (6) The
factor for Narragansett plumage color pattern, is recessive and sex-
linked. Males showing the Narragansett plumage pattern are pro-
duced only from matings of Narragansetts, but females showing
Narragansett color and males showing bronze color may bo produced
from a mating of Narragansett males and bronze females. The
reciprocal of the mating produces all bronze-colored progeny.
Work of the Federal Government
In the field of plant and animal genetics, there has been a good deal
of experimental work in making wide crosses such as crosses between
species. Certain of these results have been worth while. This is
more true of plants than of animals, although the mule is an outstand-
ing example of a useful wide cross in the animal kingdom. In most
cases, however, the hybrid proves to bo without economic value,
although this means of obtaining a cross of unusual value cannot be
overlooked.
An attempt was made by Quinn, Burrows, and Byerly at the
National Agricultural Research Center, Beltsville, Md., to effect an
intergeneric cross between the turkey and the chicken by the use of
an artificial insemination technique developed at the center. Semen
of turkey males was used to fertilize Rhode Island Red females and
semen from purebred and cross-bred chicken males was used to
fertilize turkey females. About 20 percent of the eggs laid by the
turkey females were fertile, but all except one died in the early stages
of embryonic development. In the reciprocal cross only a few of the
eggs were fertile and all of these died within a 3-day period of incu-
bation.
Although 25 percent of the fertile eggs died as embryos during the
first day of incubation, one hybrid embryo, from the chicken male X
turkey female cross, lived until it was fully developed and apparently
ready to hatch. This hybrid embryo was found dead in the shell on
the twenty-eighth day of incubation, death having occurred some
time between the twenty-third and twenty-eighth days. No daily
observations were made after the twenty^tbird day, so that the exact
time of death, and the age of the embryo when death occurred, were
unknown. The hybrid was obtained from an agg laid by a Bronze
turkey hen on July 3, 20 days after the last fertile turkey egg had
been obtained and 66 days after the removal of the turkey male.
TURKEYS
1363
The turkey-chicken hybrid was intermediate in conformation
between the chicken and the turkey. The hybrid was also lighter in
down color than the turkey, having a reddish cast in both head and
body. It had yellow shanks whereas the shanks of the turkey parent
were quite dusky. The hybrid had a distinct comb and no evidence
of the characteristic fleshy protuberance of the turkey. It also
showed a polydactylism in which the fourth toe of the left foot was
triplicated, a malformation sometimes found in wide crosses. In
various external characteristics such as head type and shape, down
color and shank color, the turkey-chicken hybrid may be said to have
shown the characteristics of the chicken rather than the turkey.
The latest development in poultry breeding for the creation of
superior strains is the building up of inbred strains in order to produce
successful hybrids by subsequent crossing. It is much more difficult
to build up inbred lines of chickens or turkeys than of many plants,
since fewer individuals can be used and self-fertilization cannot be
practiced.
Although he cannot catalog the characteristics of the turkey, and
their mode of inheritance, the scientific breeder might accumulate and
purify certain good characteristics by the process of inbreeding, which
fixes various good and bad traits of the parents in the different lines
of inbred progeny, Sires that show an accumulation of bad traits
might be discarded. A line that showed an accumulation of good
traits might be crossed with another good line, with the object of
producing superior hybrid individuals.
Because inbreeding might play an important role in the improve-
ment of turkeys in some such way as this, an experimental turkey-
breeding project was begun in 1931 by the Bureau of Animal Industry
at its range livestock experiment station, Miles City, Mont. This
project was terminated in 1935 and the results of approximately 5
years' work were summarized. One purpose of the project was to
measure the effect of inbreeding on the fertility and batchability of
eggs, the egg weight, and the egg production of Bronze turkeys. In
order to make an adequate comparison of the effects of inbreeding, a
series of outbred ma tings were maintained. These outbred ma tings
were made between unrelated or distantly related individuals, and
each year the progeny was systematically outbred with the idea of
maintaining a line indefinitely without resorting to close inbreeding
or the introduction of new stock. This plan of outbreeding included
seven matings and constituted a separate experiment that will be dis-
cussed later.
Table 4.-
-Summary of the egg fertility and hatchabilily and of egg production and egg
weight for 773 inbred and outbred Bronze turkeys
Degree of inbreeding
Coefficient
of inbroeding
Fertility
Jlatch-
ability
Production
of eggs to
.Tune 1
Average
egg weight
0. 000-0. 063
. 125- . 218
. 250- . 411
. 500- . 672
Percent
87.8
75.4
82.8
69.3
Percent
67.6
61.7
52.8
34.9
Number
47.7
42.2
39.0
41.4
Grams
83.6
Mild
Close
82.7
82.1
Intensive .. .. .-
81.5
1364 YEARBOOK, 1937
The data in table 4 show the results obtained from unrelated turkey
matings and from matings of different degrees of relationship on
fertility, hatchability of eggs, egg weight, and egg production.
Some general conclusions from this work are as follows:
(1) Mild and close inbreeding had little effect on fertility, egg
production, and egg weight when compared to outbreeding.
(2) Mild and close inbreeding had an adverse effect on the hatch-
ability of turkey eggs. The inbred lines averaged approximately 52
percent hatchability whereas the outbred lines averaged 67.6 percent.
(3) Intensive inbreeding adversely affected fcrtSity and hatch-
ability of eggs but had slight effect on production and average egg
weight.
These conclusions are taken from the final averages. However,
there was considerable variation in the results obtained from various
matings within each of the four groups. For instance, some of the mild
and close inbred turkeys gave better results in regard to the four factors
considered than the outbred turkeys that were used as controls. In
other words, it appears that it might be possible with careful selection
and mating to obtain lines of inbred turkeys that would be as good
as the outbred turkeys in these respects.
Matings were made between unrelated or distantly related indi-
viduals each year and systematically outbred with the idea of estab-
lishing a line of outbred turkeys without resorting to close inbreeding
or introduction of new stock. The method used was briefly as follows:
The start was made with stock purchased from seven different
breeders. Seven breeding pens were mated in such a way that the
males and females in no two pens were from the same source. The
progeny were individually wing-banded, which made it possible to
identify the progeny of each mating at any time. The best young
hens and the best young torn turkeys were selected in each generation
in each pen. The selected young hens from each pen remained to-
gether as a breeding unit each year and were placed in the pen pre-
viously occupied by their parents, but the selected young torn was
placed in the next pen. For example, the selected young hens from
the mating in pen 1 were placed in pen 1 the next year. The best
young torn available from this mating, however, was placed in pen 2.
The young torn turkey from pen 2 was placed in pen 3, and so on,
the young torn from pen 6 being placed in pen 7, and that from pen 7
being placed in pen 1. This revolving process was followed each year.
The plan proved to be satisfactory, simple, easily workable, and
effective in maintaining the average egg weight and improving the
fertility and hatchability of eggs and egg production. The data in
table 5 show the results obtained in the operation of this plan for 5
years. It is regrettable that it was necessary to sell the progeny of
the 1935 matings before records of egg production and egg weight
could bo obtained .
Practical breeding operations are well served by basic research,
especially in a field so new as turkey breeding. The mode of inherit-
ance of characters, the physiology of reproduction, and the study of
mating systems all have a direct application to practical problems.
Through these findings, unwise practices may be brought to light and
discarded and more efficient methods developed.
TURKEYS
Table 5. — Summary of the egg fertility and hatckabilily and of egg production and egg
weight for 390 systematically outbred turkeys
Year
Coeffici-
ent of in-
breeding
Fertility
1931 I
1932 . """ |
1933
1934 .
1935
0. 000
.000
.031
.060
. 053
Percent
72.7
85. 0
92.0
85.3 i
92.0 J
I Produc-
Hatcha- lion of
bility eggs to
I June 1
J'crcent-
55.2
56.6
71. -4
08.7
74.9
Number
44. IS
47.4
49.6
48.0
Average
egg
weight
drams
84.7
85.0
79.6
84.0
SELECTED LIST OF REFERENCES
American Poultry Association.
1930. THE AMERICAN STANDARD OF PERFECTION . . . 487pp., illllS. Buffalo.
(Revised at annual meetings.)
Asmundson, V. S., and Lloyd, W. E.
1935. EFFECT OF AGE ON REPRODUCTION OF THE TURKEY HEN. Poultry
Sci. 14: 259-266, illus.
Barrows, W. B.
1912. MICHIGAN BIRD LIFE, A LIST OF ALL THE BIRD SPECIES KNOWN TO
occur in the state ... 822 pp., illus. [Lansing]. See pp.
236-237.
Bent, A. C.
1932. LIFE HISTORIES OF NORTH AMERICAN GALLINACEOUS BIRDS: ORDERS
GALLIFORMES AND COLUMBIFORMES. C. S. Natl. Mils. Bull. 162
490 pp., illus. See pp. 323-345.
Burrows, W. H., and Quinn, J. P.
1937. THE COLLECTION OF SPERMATOZOA FROM THE DOMESTIC FOWL AND
turkey. Poultry Sci. 16: 19-24, illus.
Cline, L. E.
1933. turkey production; a complete text on breeding, feeding,
handling, marketing, and disease control. 436 pp., illus.
New York and London.
Hammond, J. C, and Marsden, S. J.
1937. DETERMINING THE SEX OF TURKEYS FROM HATCHING TO MATURITY
Poultry Sci. 16: 287-288.
Hinshaw, W. R., and Asmundson, V. S.
1936. observations on pendulous crop in turkeys. Jour. Amer. Vet
Med. Assoc. 88: 154-165, illus.
Kansas Agricultural Experiment Station.
1934. turkey production. Kans. Agr. Expt. Sta. Bien. Rept. (1932-34)
7: 87-88.
McIlhenny, E. A.
1914. the wild turkey and its hunting. 245 pp., illus. Garden City,
Marble, D. R., and Margolf, P. H.
1936. the selection and management of turkey breeders. Poultrv
Sci. 15: 225-229.
Marsden, S. J.
1936. a study of egg production in bronze turkeys. Poultrv Sci. 15-
15: 439-445.
Nebraska Agricultural Experiment Station.
1930. turkey production: the effect of crossing bronze with white
Holland and bourbon RED turkeys. Nebr. Agr. Expt. Sta. Ann.
Rept. (1929-30) 44: 39.
Ogorodny, IT. M.
1935. success in hybridization of fowls. Ascania-Nova. Bull. Agr
Sci. 1: 25. h
Quinn, J. P., and Burrows, W. H.
1936. artificial insemination in fowls. Jour. Heredity 27: 31-37, illus.
1366 YEARBOOK, 1937
Quinn, .7. P., Burrows, W. H., and Byerly, T. C.
1937. turkey-chicken hybridization. Jour. Heredity 28: 169-173, illua.
Robertson, W. R. B.
1920. INHERITANCE OF COLOR IN CROSSES BETWEEN THE VARIOUS BREEDS
of the domestic turkey. Mo. Agr. Expt. Sta. Bull. 236: 88-89.
1930. REVISED terminology for the chief color factors concerned in
crosses ABOSd the hkeeds of the turkey. (Abstract) Anat.
Rec. 44: 289.
Scott, II. M., and Payne, L. P.
1934. the effect of gonadectomy on the secondary sexual characters
of the bronze turkey (m. gallopavo). Jour. Expt. Zool. 69:
123-136, illus.
Serebrovsky, A. S.
1929. observations on interspecific hybrids of the fowl. Jour.
Genetics 21 : [327]-340, illus.
Shiwago, P. J.
1929. SUR les garnitures chhomosomales des poules et des dindes.
Compt. Rend. Acad. Sci. [Paris] 188: 513-515, illus.
Sokolov, N. N., Tiniakov, G. G., and Trofimov, I. E.
1934. on the chromosomes of the domestic turkey. Biol. Zlmr. (Jour.
Biol.) 3: 648-[654], illus. [In Russian. English summary, p. [654]. J
Taibel, A.
1933. valore genetics del colore GRIGO-AZZURO DEL P1UMAGGI0 VEL
TACCHINO DOMEST1CO. [THE GENETIC CONSTITUTION OF THE BLUISH-
GRAY PLUMAGE IN THE DOMESTTC TURKEY.] lliv. Avicult. 3:315-316.
Warren, D. C, and Scott, II . M.
1935. an attempt to produce turkey chicken hybrids. Jour. Heredity
26:105-107, illus.
Werner, O. S.
1931. the chromosomes of the domestic turkey. Biol. Bull. 61: 157-164,
illus.
Some workers identified with turkey-breeding work at Stale
and Federal experiment stations
State Worker Location
California L. W. Taylor,1 V. S. Asmundson Davis.
Indiana C. W. Carrick,1 E. E. Schnetzler LaFayette.
Iowa H. L. Wilcke 1 Ames.
W. R. B. Robertson Iowa City.
Kansas L. P. Payne,* H. M. Scott, D. C. Manhattan.
Warren.
Kentucky J.H. Martin,1 W. M. Insko, Jr Lexington.
Michigan C. G. Card,1 F. N. Barrett East Lansing.
Nebraska F. E. Mussehl,1 H. E. Alder Lincoln.
New Mexico L. N. Berry : State College.
North Dakota F. E. Moore,1 O. A. Barton Fargo.
Oklahoma R. B. Thompson,1 Robert Penquite, Stillwater.
0. E. Gofif.
Pennsylvania H. C. Knandel,1 D. R. Marble, P. H. State College.
Margolf.
Utah Byron Alder ' Logan.
Wisconsin J. G. Halpin,1 G. E. Annin Madison.
Wyoming P. S. Hultz,1 M. O. North Laramie.
U. S. Department Berley Winton,1 S. J. Marsden, Washington, D. C.
of Agriculture, C. W. Knox, J. P. Quinn, W. H.
Bureau of Ani- Burrows,
mal Industry.
1 Head of deimrtmenl or section.
DUCK BREEDING
A. R. LEE, Associate Poultry Hus-
bandman, Animal Husbandry Divi-
sion, Bureau of Animal Industry
R
ELATIVELY little information is available on the breeding of ducks
and practically no genetic investigations have been made on the im-
provement of the breeds. Because of the lack of records, no survey of
duck breeding has been made, nor has the Department of Agriculture
used ducks in its breeding investigations. The same is true of practi-
cally all the State experiment stations. On the otlier hand, although
Federal research in poultry breeding has not dealt specifically with
ducks, it has dealt with fundamentals in genetics, and principles of
management have been worked out that arc applicable to all poultry,
including ducks. The size and extent of the duck indtistry in this
country seem to warrant careful study of this important aspect of
poultry breeding.
Duck raising is conducted as a side^ line in nearly all sections of the
United States, where ducks are kept in small flocks on general farms.
These farm flocks are kept primarily for meat production and while
the birds have been selected for size and market type, very little at-
tention has been given to careful pedigree breeding. Commercial
duck raising has been extensively developed as a highly specialized
industry on Long Island, N. Y. (fig. 1) and to some extent on a few
commercial duck farms in several other sections of the country.
Relatively little has been published on the methods used in the selec-
tion and breeding of ducks on these commercial duck farms.
Few ducks have been bred for high egg production in this country
because of the lack of demand for duck eggs as food. Relatively few
ducks of the breeds especially adapted for egg production have been
kept here and few ducks with high egg records have been produced.
That ducks can be bred for very high production has been demon-
strated in many egg-laying contests in other countries, in which the
duck records have equaled or exceeded the best records made by chick-
ens either here or abroad.
PRODUCTION OF GREEN DUCKS
Although most flocks of ducks are small, about 12 million ducks are
raised each year in the United States. They are raised in every State,
the greatest total farm production occurring in the North Central
States. Large commercial duck farms in New York place that State
first in total number of ducks raised, Long Island alone producing
nearly a million annually. These market ducks from the large com-
mercial flocks are called green ducks. They are hatched in the
winter and early in the spring, forced for rapid growth, and marketed
1367
1368
YEARBOOK, 1937
at 9 to 13 weeks of age when they attain a weight of 4 % to 6 pounds
each. Ducks produced on general farms are not forced for rapid
growth; they are hatched in the spring and marketed in the fall and
winter when they are 5 to 7 months old. These ducks from farm
flocks, although twice as old when they are marketed, are little if
any larger than the green ducks.
The number of ducks raised in this country is about three tunes the
number of ereese but less than two-thirds the number of turkeys.
Figure 1. — The I'ekin duck is [he only breed used for commercial duck farming. A
large number of duck farms have been developed along the inlets of Long Island.
Duck production is similar to turkey production in that both ducks and
turkeys are raised primarily for market as young birds, and relatively
few breeders or mature buds are kept. While chicken and turkey
production have shown a marked increase during the last 25 years,
duck production is barely holding its own. Ducks are primarily in
demand in the large cities, especially among persons of foreign extrac-
tion. The number of ducks kept in proportion to the total population
is much lower in the United States than in most other countries, where
there is a better demand for duck meat and for duck eggs.
ORIGIN AND HISTORY OF DOMESTIC DUCKS
All domesticated ducks, with the exception of the Muscovy, are
descended from the wild mallard (fig. 2). While actual references to
ducks go back to only a few years previous to the Christian era, it is
reasonable to suppose that wild mallards were domesticated at a much
earlier period than this. Common domestic ducks of Europe, among
which there was a variety of colors, were brought to the United States
by the early settlers.
There are three classes of ducks — the meat class, the egg class, and
the ornamental class. Only a few representative breeds of each class
DUCKS
1369
will be discussed in this article. In the meat class, the Rouen, Ayles-
bury, Pekin, Cayuga, and Muscovy are among the well-known breeds.
The Rouen, which has the same color markings as the wild mallard,
shows the effect of domestication by its greatly increased size and
superior fleshing qualities. This breed originated near Rouen,
France, whence it derives its name, but it was greatly improved in
England, where it was bred for very large size, the males weighing
9 to 11 pounds alive and the females 8 to 10 pounds. It was brought
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bgf.fJ-.-
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M|2 ^^^T-i
' ■
HHD.m^ .
V"-«
1 * ■ -* -
Figure 2— Wild mallard, drake (A) and duck (B)— the ancestors of all but one of
our domestic breeds of ducks.
into the United States about 1850 and became quite popular but is
now kept in this country primarily by fanciers.
The Aylesbury is a white duck that originated in England early
in the nineteenth century. It is a large duck with a massive body,
that is carried nearly horizontal. The Aylesbury duck was first
brought into this country about 1849 and was used on the first duck
farms, but was eventually replaced by the Pekin. Duck breeders in
this country consider it less hardy than the Pekin.
The Pekin duck (fig. 3) originated in China and little is known of
its history in that country. It is a white duck of medium size, more
upstanding in type than the Aylesbury, an excellent market bird and
noted for its vigor and hardiness. The breed was brought into the
United States from China in 1873. It rapidly became popular and
soon replaced all other breeds for commercial duck raising. Crosses
were made of the Pekin with Aylesbury and other breeds, but the
pure Pekin was found to be much better adapted for commercial
duck farming and has since maintained this position as the best and
only commercial market duck. The first small importations of Pekins,
from which most of the present commercial flocks are descended,
were very good market ducks, not greatly different in appearance,
size, or other economic characters from those of today.
The Cayuga duck (fig. 4, D) is of interest because it was produced
in Cayuga County, N. Y., and also because it is solid black in color.
It was developed about 1850 and was just becoming well known
when the Pekin, which was better adapted for the market, came along
and replaced it.
138904°— 37-
-87 ++
1370
YEARBOOK, 193 7
The Muscovy, or Brazilian, duck is a native of Brazil and is con-
sidered a different species from the wild mallard and from the other
domestic ducks. The period of incubation for Muscovy eggs is 33
to 35 days, compared with 28 days for eggs of other domestic breeds
of ducks. The breed was introduced into the United States between
1840 and 1850. The Muscovy drake is about one-third larger than
the duck, while in all
the other m a r k e t
breeds the male and
the female are practi-
cally equal in size.
The egg-laying class,
of which the Indian
Runner (fig. 4, E) is
the outstanding breed
in this country, was
brought into United
States only about 40
years ago. It is an
upright Penguin type
of duck noted for great
prolificacy. It was
named Indian Runner
because of its supposed
introduction from East
India, but the evidence
appears to show that it
was a selected duck of
a type common in Bel-
gium and the Nether-
lands. Because of its
small size it is not so
well adapted as the Pekin for meat production. The Khaki-Camp-
bell duck is a popular breed of this class in foreign countries.
In the ornamental class there are ducks of all sizes, types, and colors,
which indicates that great variation has been brought about through
selection and breeding. The Call (Fig. 4, A and B) and the Black
East India are bred for extremely small size, the White and Gray
Calls being miniatures of the Pekin and Rouen, respectively, while
the East India is a small-sized Cayuga. The Mandarin and the Wood
ducks are the most ornamental of the small breeds of waterfowl.
Their plumage contains many brilliant colors and is handsomely
marked. In the ornamental class there are also larger ducks, such
as the Crested White (Fig. 4, C), which is distinguished by a well-
developed crest on the top of its head. Figure 4 shows a few of the
variations that occur in the breeds of ducks.
Improvement by Breeding
Improvement of ducks of the meat class in this country has been
largely confined to the selection of a few individuals notable for size,
type, and rapid growth out of the large number raised for market
each year. On commercial duck farms 40 or more young ducks are
Figure 3. — Most of the commercial flocks of ducks iu
this country came from two small importations of Pekin
ducks hrought from China in 1873.
DUCKS
1371
Hgure 4. — Great variation has been produced in ducks through selection and breeding:
A, Gray Call male; B, Gray Call female; C, Crested White; D, Cayuga; E, Indian
Runner.
1372 YEARBOOK, 1937
marketed annually from each female breeder. Selection of a few
of the outstanding birds from a large flock does not give an accurate
measure of the breeding value of the flock, but this selection, starting
from high-quality stock, has resulted in the production of very uniform
flocks of Pekin ducks. These ducks are noted for their rapid growth
and for uniformity in size and type. Pekin ducks have not been bred
or selected for high yearhy egg production but they lay very steadily
during the months when eggs are desired for hatching.
PRINCIPLES OF BREEDING
An article by Jull in the 1936 Yearbook of Agriculture1 contains a
thorough discussion of the principles of breeding, the use of inbreeding
and cross-breeding, breeding for disease resistance, and other aspects
of poultry breeding that apply to ducks no less than to chickens. A
careful study of the breeding investigations that have been made with
chickens and with turkeys should be of much assistance to those in-
terested in improving the breeding of ducks. No attempt will be
made to discuss these breeding principles in detail here— for this in-
formation the reader is referred to Dr. Jull's article.
Jull stresses the importance of what he calls a three-p program, in-
volving production records, pedigrees, and progeny testing. Produc-
tion records, he points out, are of great value; yet many good individ-
ual producers fail to produce good offspring. Pedigree breeding, in
which detailed records are kept of the breeding birds and their off-
spring, is an improvement over breeding from production records
alone, but again there is no positive assurance that a bird with a good
ancestry will always produce good offspring. Since ducks are rarely
trap-nested, practically no thorough pedigree breeding has been car-
ried on with them. Progeny testing, which is the best method of
evaluating any poultry breeding stock, has not as yet been applied
to the breeding of ducks in this country.
In fact, ducks offer a virgin field for poultry breeding research,
especially in the inheritance of meat characters. The first practical
steps in a breeding program would be the use of the production record,
the pedigree, and the progeny test. They involve expense, however,
in the keeping of records, securing individual egg records, and main-
taining breeding ducks beyond the age now customary; and duck
breeders apparently do not feel that this expense is justified under
present conditions. A very different situation exists among breeders
of chickens, who are primarily interested in breeding for eggs.
Breeding for Size and for Quality of Flesh
Ducks are kept and selected primarily for flesh production. Good
body type and rapid growth to market size are desired for economical
production. But very little research work has been done on the breed-
ing of poultry for meat or flesh production or on the inheritance of
body size. W. F. Waters of the Iowa Agricultural Experiment Sta-
tion has shown that inheritance of body size in chickens is extremely
complex, andexperiments in crossing a large and a small breed at the
National Agricultural Research Center, Beltsville, Md., indicate that
a large number of genes are involved.
i See list of selected references, p. 1377
DUCKS 1373
As already indicated, breeding work with Pekin ducks lias been
confined principally to the selection of birds of the desired market
type, size, and weight, that is, those weighing about 5}i pounds when
dressed at 10 to 12 weeks of age. A larger Pekin can easily be pro-
duced, but it would not be so well adapted to the market demand;
moreover, large heavy ducks are not usually as good breeders as those
of medium size. Since only a small percentage of the ducks raised
are kept for breeding, it is a relatively easy matter to select good-
sized, rapid-growing, and early-maturing birds for the breeding flocks.
INBREEDING AND HATCHABILITY
The Pekin ducks have been bred for a longer period without intro-
ducing outside stock than have any of the popular breeds of chickens.
No work on the use or effect of inbreeding in the egg-laying breeds of
ducks has been reported. The results secured with inbreeding
chickens for egg production should be applicable to the breeding of
ducks. Almost all the Pekin ducks in this country are descended
from two small importations. There have been periods when it
would appear that many of the flocks on Long Island were being too
closely inbred and that this resulted in widespread poor hatchability.
From experiments with chickens it has been concluded that hatcha-
bility tends to decrease and chick mortality tends to increase with
close inbreeding.
Hatchability is an inherited character that can be improved by
careful selection and breeding. However, the fact that Pekin ducks
are usually mass mated and are rarely trap-nested makes it very
difficult to select for hatchability. In these mass ma tings there is
usually one male for every six or seven females. It would be very
desirable to select males for breeding on the basis of high hatchability
of the eggs of their dam and their progeny.
Cross-Breeding
It is sometimes claimed that cross-breeding produces increased
vigor in the offspring. There has been very little cross-breeding of
ducks except in farm flocks where the birds are bred indiscriminately.
The purebred Pekin is the only breed used on commercial duck farms
in this country for meat production. Ducks of the Aylesbury breed
were occasionally crossed with the Pekins in this country some years
ago, but the reports of this introduction of Aylesbury blood have been
unfavorable and these crosses have been entirely eliminated from the
breeding flocks. It is reported that outcrosscs of the Pekin on the
Aylesbury are occasionally made in England to improve the breeding
qualities of certain flocks that show poor fertility and lack of vigor.
The mule duck, a cross of the Muscovy on the common domestic duck,
is occasionally made, especially in the Southern States. The hybrids
are not fertile when bred together, but they will breed to some extent
with either parent race.
Selection for Disease Resistance
Ducks are considered less subject to disease than chickens, and
mortality in commercial flocks, both in the young ducks and in the
mature stock, is usually much less than with chickens. Commercial
1371
YEARBOOK, 193,
duck breeders started with good Pekin stock and appear to have kept
their ducks relatively free from disease by good management of the
breeding flocks. No experimental work has been reported, however,
on breeding ducks for disease resistance. There has doubtless been
much less chance for the spread of disease than in the case of chickens,
since most ducks are very healthy, and commercial duck fanning is a
highly specialized industry largely conducted on very light sandy soil
by a small number of breeders who usually batch and raise tbeir own
Figure 5. — I'ekin clucks, 12 weeks of age, weighing 6 pounds each,
and ready for market.
stock, while the ducks on general farms are kept in very small flocks
and hatched and reared by natural methods with very little trade in
day-old ducklings or breeding stock.
Bkekding for Meat Production
On commercial duck farms picking out breeders has been almost
entirely a matter of selection from appearance and by handling the
birds. Ducks have been bred from large flock matings; few if any
special matings have been made; the birds are not trap-nested and
there has been no selection of outstanding breeders on the basis of
individual pedigree records. However, the uniformity of the original
stock and the selection of small flocks of breeders from very large
numbers of ducks have brought about a much greater uniformity in
type and size than can be found in any other kind of poultry (fig. 5).
The best flocks of ducks are so highly bred that there is practically
only one market grade.
The best-appearing young birds are selected when they are 8 to 10
weeks old and reserved for further selection as breeders. At this age
the birds intended for market are changed to fattening rations.
DUCKS 1375
Breeding males are usually selected during June and females during the
early part of July. When these selected ducks reach market age they
are again carefully examined and only the best are kept. Breeding
ducks are selected for good length, width, and depth of body, and for
early maturity. While good size and quick growth are desired, stock
showing any sign of coarseness is discarded. Heavy birds with very
deep keels have a tendency to take on too much fat and are likely to
show low egg production, poor fertility, and lack of vigor. Most
breeding ducks are kept only through their first laying season, as
young ducks are better producers and lay earlier than older ones. The
use of only mass matings and this restriction to young breeding stock
made it impossible to do any careful pedigree breeding or progeny
testing. Retaining a few of the best breeders for a second season and
keeping adequate records for these birds would be worth trying.
Young Pekin ducks are efficient producers of meat. The young
ducks raised on commercial farms have been selected and bred for
rapid growth and at 10 to 12 weeks of age they are nearly as large as
they are at maturity. At 12 weeks of age Pekin ducks weigh about
6 pounds, or 50 times their initial weight. Chickens fed for rapid
growth and marketed as broilers at 12 weeks of age weigh about 2%
pounds, or less than one-half as much, as ducks of the same ago, while
at maturity the ducks weigh about the same as chickens.
Up to about 1910 market growers exhibited their ducks at the
poultry shows and competed to some extent in the sale of breeding
stock meeting standard requirements. Since that time commercial
duck farmers have shown much less interest in the requirements of the
standard, largely disregarding any points that did not meet their own
particular market demands.2
Breeding for Egg Production
Ducks of the egg-laying class have been selected and bred for very
high egg production. Records of individual ducks and of small flocks
show egg yields as high in number as the best records made by hens,
and higher in total weight. In this country there is very little interest
in the egg-producing breeds of ducks, largely because of lack of demand
for duck eggs for market. The Indian Runner duck, which is one of
the best egg producers, experienced a moderate boom beginning about
1907, but the interest in the breed lasted only for about 7 or 8 years.3
Duck eggs are usually in good demand only early in the spring, especial-
ly around Easter time. There has been some indication of a slightly
increased demand during the last year or two in some markets.
Duck egg-laying contests have been conducted in England and other
foreign countries, where the egg breeds are kept much more extensivoly
than they are in the United States. Trap nests used in Germany are
■ The first standard for Pekin ducks was published in 1874 and ilie following year this breed was admitted
!o the standard of the American Poultry Association. In 1888 the following standard weights were adopted:
Old drake, 8 pounds; old duck, 7 pounds; young drake, 7 pounds; young duck, Cpounds. In 1910 the weights
were increased 1 pound in each class and more emphasis was placed on development of ducks with deep
bodies and long keel bones.
3 The Indian Runner duck standard was first adopted by the American roultry Association in 1808. Rela-
tively few changes have been made in the standard and these changes have been largely confined to minor
points. Standard weights aro 4H pounds and 4 pounds for adult drakes and ducks, respectively. The
standard calls for a long slender bird with carriage approaching the perpendicular. The so-called utility
type of Indian Runner duck, bred only for egg production, is less upright in carriage and not so slender as
the standard type, which is bred primarily for exhibition.
1376
YEARBOOK, 1937
illustrated in figure 6. The 161 ducks entered in one of the English
contests averaged 225 eggs in 48 weeks. The average weight of all
eggs was 2.57 ounces, which gives an egg production per duck of 36
pounds, 3 ounces, or about eight times the average weight of the ducks
of the egg-laying class. This is a much greater average production
per pound of body weight than is made by chickens in the egg-laying
iigurv 6. — Trail nesls used in Germany in pedigree breeding of dueks
|<ir egg prodiietion.
contests. Many individual duck records of over 300 eggs per year have
been made, while the highest individual production runs over 360
eggs. The use of the single-pen system or of trap nests for keeping
records of individual ducks goes back only about 16 years in England,
but great progress has been made in improving egg production during
these years. Considerable inbreeding has been used, and pedigree
breeding and the keeping of production records have been practiced.
Progeny testing offers an opportunity for still greater improvement
in breeding for egg production.
Improving Size and Color of Eggs
Size and color of duck eggs are inherited so that, where individual
records are kept, careful pedigree breeding and selection will lead to
material improvement. It is desirable to maintain good egg size in
both the egg and the meat breeds. Considerable variation occurs in
the color of duck eggs, which have a tendency to show various shades
of green. This is natural, since the wild mallard produces eggs with
DUCKS 1377
green shells. Shell colors range from -white for the Pekins and well-
bred Indian Runners to green for Rouens and dark green or black for
the Cayuga. When the Cayuga and Black East India ducks begin
to lay, their eggs are almost black, but as production increases the eggs
gradually lose their black color and become dark green. White-
shelled eggs are desired for market and the popular egg breeds show the
great improvement that has been made in selecting and breeding for
white eggs. Duck eggs produced by farm flocks on range, which are
poorly fed, are not considered to be of as good a flavor as duck eggs
produced from well-managed flocks.
Ducks offer a virgin field for poultry breeding research, especially for
the inheritance of meat characters, since ducks are used almost ex-
clusively for meat. GENETIC RESEARCH
Very little information has been reported on the genetic composition
of the domestic breeds of ducks. The principal plumage-color-in-
heritance work in this country has been conducted by R. G. Jaap at
the University of Wisconsin. A few other research reports on the
breeding of ducks will be found in the list of references. Jaap studied
the inheritance of three types of white spotting. Two of these types
were found to be simple recessive and the third type exhibited incom-
plete dominance. The dominant type of white markings is found in
the Fawn and White and the Penciled Indian Runner varieties and is
due to the homozygous expression of a dominant type of white spotting,
RB, designated "runner." The two recessive types of spotting are
found in ducks having white primary wing feathers. One class is due
to the heterozygous expression of the genes for runner, Rr; the other
to a recessive gene, w, for white primaries.
Jaap also reported on three allelomorphic genes which produce
differences in the mallard-plumage pattern. These three alleles are
restricted mallard color, Mr, mallard, M, and dusky mallard, md.
Another article describes the effects of a recessive gene which produces
a light color phase in mallards. In the juvenile feathering, in the adult
plumage of the female, and in the summer plumage of the male the
light-phase gene produces a lighter color tone in the ducks that are
genetically restricted mallard color, mallard, or dusky mallard color.
During the summer the adult Rouen male takes on a drab plumage
similar to the plumage of the female. After the fall molt the male
again assumes his normal bright-colored plumage. Young drakes also
have this drab female coloring before they take on their adult plumage.
SELECTED REFERENCES
British Duck Keepers Association.
YEARLY REPORTS ON EGG LAYING CONTESTS. Brit. Duok Keepers ASSOC.
Yearbooks. Swanky, Kent (England).
Oolombi, C.
1934. KAPPORTO FRA LA PRODTJZIONE DELLE NOVA E L'ATTIVITA 1POFISARIA
ntella gallina. 5th World's Poultry Cong. Rept. Proc, v. 2,
pp. 421-425.
The Feathered World.
1927. dttcks, the standard and most authoritative work upon all
WATERFOWL YET PUBLISHED . . . 160 pp., illuS. London.
Finn, F.
1913. SOME SPONTANEOUS VARIATIONS IN" MALLARD AND MUSCOVY' DUCKS.
Avicultnral Mag. 4: 82-87, 106-108, ilhis.
1378 YEARBOOK, 1937
Goodale, H. D.
1911. studies on hybrid ducks. Jour. Expt. Zool. 10: 241-254, illus.
Harper Adams Agricultural College.
yearly egg laying trial reports. Newport, Shropshire, England.
Horton, D. H.
1928. the growth op white pekin ducklings. Poultrv Kci. 7: 163-167.
Jaap, It. G.
1933. inheritance of white spotting in" ducks. Poultry fcici. 12: 233-241,
illus.
1934. alleles of the mallard plumage pattern in ducks. Genetics
19: 310-322, illus.
1933. light-phase mallakd ducks. Jour. Heredity 24: 467-472, illus.
Jull, M. A.
1936. superior breeding stock in poultry. V. ,S. Dept. Agr. Yearbook
1936: 947-995, illus.
Lamon, H. M., and Slocum, It. Jt.
1922. ducks and geese. 231 pp., illus. Xew York.
Lee, A. It., and Haynes, S.
1933. duck raising. U. S. Dept. Agr. Farmers' Bull. 697, 22 pp., illus.
Lipscomb, J. K., and Howes, II.
1934. ducks and geese. 38 pp., illus. Loudon. (Brit. Mm. Agr. and
Fisheries) .
Phillips, J. G.
1915. experimental studies of hybridization among ducks and pheas-
ants. Jour. Expt. Zool. 18: 69-143, illus.
Punnett, It, C.
1930. a sex-linked chakacter in ducks. Nature [London] 126: 757.
1932. note on a sex-linked character in ducks. Jour. Genetics 25:
191-194.
Robinson, J. H.
1924. teie growing of ducks and oeesk for profit and pleasure . . .
447 pp., illus. Dayton, Ohio.
ItOGERON, G.
1903. leb canards, considerIjs a l'etat sauvage, et comme oiseaux
d'agrioment en domesticitb; l'elevage des JEUNKS CANARDS . . .
434 pp., illus. Paris.
Walther, A. It., Hauschildt, J., and Prufeh, J.
1932. EIN wirtshaftlich wichtiger geschlechtsgebundene faktor bei
enten. Zuchter 4: 18-22, illus.
Waters, N. F.
1931. inheritance of body-weight in domestic fowl. R. I. Agr. Expt,
Sta. Bull. 228, 105 pp., illus.
THE BREEDING
OF FUR ANIMALS
FRANK G. ASHBROOK, Principal Biologist
in Charge, Section of Fur Resources, Division of
Wildlife Research, Bureau of Biological Survey
J. HE science of breeding can play an' important part in conserving
and developing the fur resources of the United States in two vital ways.
(1 ) Research is needed to throw light on the breeding habits and gesta-
tion periods of wild fur animals so that an intelligent conservation
program may be based on the biological needs of the animals con-
cerned. (2) As in the case of domesticated livestock, breeding re-
search is needed to give a more certain foundation for the production
of fur animals in captivity— notably the silver fox and the mink. To
state which of these two fields is the more important is difficult.
Without a vigorous conservation program based on sound scientific
knowledge there is great risk of completely wiping out one of the
oldest of the valuable resources of the country. On the other hand,
fur farming is rapidly becoming an important farm enterprise, and if
it is to develop its full possibilities, further information is greatly
needed at various points. The industry is all the more significant
because it does not compete with any other ldnd of farming and it
utilizes land that is of little or no value for any other crop.
A brief backward glance will show what has happened to the fur
resources of the United States to make conservation in the wild so
essential and propagation on fur farms a lucrative undertaking of such
great promise. In almost every civilization furs have been among the
most valued articles of commerce. This was true among the Chinese
3,500 years ago, and later among the Greeks and the Komans. In
medieval Europe fur was a luxury much sought after — and incidentally,
men made greater use of it for clothing than did women. It was not
until after the discovery of North America, of course, that the world
fur trade really got into its stride. That it early became an enor-
mously profitable business on this continent is attested by the fact that
an Indian trapper could often be induced to part with his winter's
catch, worth hundreds of dollars, for a blanket or two and a bottle of
rum — and perhaps not very good rum. Among the great fortunes
amassed in this game the outstanding example is that of John Jacob
Astor.
In these circumstances, with pelts readily obtained and profits large,
no attention whatever was paid to the question of the possible exhaus-
tion of this source of wealth that nature distributed with a prodigal
hand. The more furs there were on the market, the more popular furs
became. The luxury of the rich became the necessity of the moder-
ately well to do. The trap lines were run not less but more intensively,
to the profit of everyone — the professional trapper, the landowner,
1379
1380 YEARBOOK, 1937
the farmer who could turn a few extra dollars without much trouble,
and a large army of wholesalers, factory owners and workers, and
retailers and their employees.
Naturally a depletion of fur resources resulted. This cannot be
attributed, however, entirely to overeagerness in trapping. The dis-
appearance of the wilderness, natural habitat of the fur-bearing ani-
mals, was a major factor. Nevertheless, even today the trappers
and fur farmers of the United States receive $60,000,000 a year for
the raw furs they bring to the market. The annual retail turn-over
is several times that amount; in 1929, the peak year, it reached half
a billion dollars. The United States is in fact the largest consuming
market in the world.
PRODUCTION AND DEMAND FOR FURS
Today, instead of the United States being the world's chief source of
fur supply, this country does not produce enough to meet znore than
a third of its own demand. Twice as many foreign as domestic furs
are now being used in this country, and the demand is increasing
rather than decreasing. To meet this demand, trappers still take fur
animals from the wild with the same extravagant disregard of main-
taining or increasing whatever supply is left. It is unquestionable
that our natural fur resources will be completely exhausted, unless
measures are taken to strike a proper balance between supply and
demand.
In this connection there is much need for greater knowledge re-
garding production. At present no one knows what would constitute
BEFORE the development of fox farming there apparently occurred
in the common red fox two distinctly different mutations to black
(silver) — one among foxes in Canada, giving rise to what are now
called standard silvers, and one among foxes in Alaska, giving rise
to Alaskan silvers. Beginning in 1928 the Bureau of Biological
Survey conducted research to determine the inheritance of the major
color types, and B. L. Warwick and the late Karl B. Hanson worked
out a hypothesis according to which two dominant genes, A and B,
and their recessives, a and b, accounted for all the principal color
variations. The results of experimental crosses and an analysis
of a large number of litters from recorded matings made by fox
farmers substantiated this hypothesis. By refemng to a simple
genetic chart, it is now possible to determine the expected results of
any method of breeding the nine basic combinations of these two pairs
of genes. This research indicates the possibilities in the study of
the inheritance of fur color, which is of primary importance in
fox fanning.
FUR ANIMALS 1381
a proper balance. We do not know, for example, whether we are
producing 10,000,000 muskrats a year and trapping 13,000,000 or
producing 5,000,000 and trapping 25,000,000. We can be pretty sure
that we are trapping more than we are producing; but it is important
to find out how many more. Almost every State has some fur
resources that are a source of income for some of its citizens. The
methods of handling these resources are almost entirely haphazard,
and in fact few State game and conservation commissions have given
sufficient serious thought to the matter. In most States there is no
provision for keeping a record of the furs taken each year. In the
case of some of the most valuable fur bearers — martens, fishers,
wolverines, and otters — the situation has become so serious that the
Bureau of Biological Survey has appealed to all State game and
conservation commissions to protect them with a 5-year closed period,
as the only way to forestall their extermination.
REPRODUCTIVE CYCLES
The usefulness of breeding data in this situation may be illustrated
by the case of the marten (fig. 1). At its experiment station near
Saratoga Springs, N. Y., established in 1923, the Bureau has been
studying the breeding and the gestation period of the marten. As a
result it has found that a period of 9K months elapses between the
time of copulation and birth. With so long a period of gestation,
many pregnant females are bound to be destroyed under the prevailing
system of open and close seasons. It is obvious that unless the
trapping season for a fur animal corresponds accurately with its
gestation-free period, the close season will not accomplish what it is
intended to: the prospective generation will be destroyed along with
the one trapped. Even this precaution, however, would be ineffective
in the case of the marten or the fisher, for their gestation periods are
too long. A 5- or 10-year closed period is necessary to prevent
local or even general extermina,tion of these two fur animals.
The available information on the reproductive cycles of the wild
fur-bearing animals is very meager. A review of the literature shows
that very little research has been conducted to determine their actual
breeding seasons, postnatal development, and gestation periods.
Practically all that is now known has been learned by observing the
living animals. Few investigators have studied actual embryological
material. The one outstanding contribution to the embryological
science of fur animals is that of Hartman,1 of the Department of
Embryology, Carnegie Institution of Washington, at Baltimore, Md.
This paper presents a study of the physiology of growth and repro-
duction, the embryology, the rate of intra-uterine and postnatal
growth, and the breeding season. More information of this kind is
vitally important to any programs of conservation, restoration,
restocking, or transplanting, as well as to the success of any effort to
produce fur species in captivity. Conversely, it is also important
in successful control of noxious animals, which should be most inten-
sively hunted throughout the period preceding the arrival of the
young. Similarly important is definite knowledge of the molting and
1 Hartman, C. Q. the breeding season of the opossum (didelphts vikginiana) and the rate of
INTKA-UTERME AND POSTNATAL DEVELOPMENT. Jour. Morph. and Physiol. 4(5: 143-215. 1928.
1382
YEARBOOK, 193 7
prime-fur cycles, for, with dependable data at hand, trapping may be
confined to the time when a given fur has its maximum value. At
present this is rather vaguely considered to be the period of cold
weather.
This kind of knowledge is fragmentary in comparison with what
has been developed in the case of the domestic animals, which have
Figure 1. — The marten, one of our most valuable fur animals,
is now in danger of extinction.
been under close observation over long periods of time. The place
to begin, however, is at the beginning, no matter how elementary it
may seem.
RAISING FUR ANIMALS IN CAPTIVITY
Raising animals in captivity as a means of supplying the need for
furs is an industry that is both new and not new. The Chinese have
for centuries bred sheep, goats, and dogs for their pelts. The out-
standing example of a domesticated animal bred specifically for this
purpose is the Karakul sheep, which has long been produced for lamb-
skins on the uplands of Bokhara in central Asia. Afghanistan is
now perhaps the most important center of this industry, and the
annual production of lambskins there is (1936-37) 1,200,000; the
FUR ANIMALS
1383
Union of Soviet Socialist Republics is next, with an annual production
of 900,000 skins. About 30 years ago Karakul sheep raising was
started in what was then German Southwest Africa, and today the
farmers of that region are producing annually about 700,000 skins
and shipping them to the raw-fur markets of the world. Karakul
sheep are also being produced in the United States, but there are few
purebred animals in
this country. The
foundation stock
came from small im-
portations from
Bokhara in 1909,
1913, and 1914. Fur-
ther importations are
next to impossible.
The Federal quaran-
tine regulations pro-
hibit direct importa-
tion into the United
States, and it is too
expensive to make in-
direct importations by
holding the animals
for the required length
of time in another
country.
In the face of this
situation the Bureaus
of Animal Industry
and Biological Survey
have been cooperating
in a breeding experiment that promises favorable results. Since it
would be almost impossible to increase the breed to any appreciable
extent from present stocks of purebred animals, the Department has
been carrying on cross-breeding experiments with Karakul X Black-
faced Highland and Karakul X Corriedale at the National Agricul-
tural Research Center, at Beltsville, Md.
The most spectacular and important development in fur-animal
production, however, is in silver-fox farming (fig. 2). This develop-
ment has taken place during the last 40 years, and though brief, the
history of the industry has been sensational. Two Canadian fanners
on Prince Edward Island, Charles Dalton and Robert Oulton, started
to experiment in 1894 with cross and black (silver) foxes, some cap-
tured and some purchased. They bred the foxes in captivity and
finally obtained some entirely black and silver puppies. The neigh-
bors soon learned of their secret operations and before long several
fox farms were established on the island. It was generally under-
stood that Dalton and Oulton were making money, but it was not
until the 1910 sales figures were published that the extent of their
profits became known. In that year they received for 25 pelts an
average price of $1,339. One pelt brought the all-time high price of
$2,627. This started a fox-farming boom and sent the prices of
Figftre 2.-
The production of silver foxes on farms now
(1936) exceeds 200,000 annually.
1384 YEARBOOK, 1937
breeding stock skyrocketing. The boom collapsed at the beginning
of the World War in 1914, but in 1923 people were again investing
anywhere from $500 to $5,000 per pair in foxes, which in some cases
they had never seen. By 1927 the unhealthy speculation in breeding
stock had died out and ranchers went to work producing the animals
for the fur. „ „ _,
Production on I ox Farms
Fox farming today represents the greatest development thus far in
raising fur animals under strictly controlled conditions. It can still be
considered a relatively new industry, however, since practically all the
development in production has taken place since the World War.
The number of pelts produced and sold in the United States is esti-
mated to have increased from 6,000 in 1923 to 200,000 in 1935. The
total value of the sales increased from $819,429 in 1923 to $7,719,600
in 1928. During the next 3 years prices declined because of the
depression and the increased production of skins, but from a low point
of $3,472,200 in 1931 they advanced to $7,114,500 in 1934.
Foxes are grown successfidly throughout the northern half of the
United States, from New England westward to Washington and
Oregon, and in the cooler parts of California. The greatest numbers
of silver foxes are produced in Wisconsin, Minnesota, and Michigan,
and these three States are contributing more than 50 percent to the
annual crop of pelts. The largest two companies in the world pro-
ducing silver foxes operate in Wisconsin. Each maintains about 7,600
breeding pairs. The other principal fox-farming centers are in the
Rocky Mountain region, including Oregon and Washington, and in
the New England States, Illinois, Ohio, New York, and Pennsylvania.
In Canada, fox farminghas had a development similar to that in the
United States but on a somewhat smaller scale. In 1923 sales of
pelts from Canadian fox farms were slightly greater than in this
country. In 1935 the mimber of Canadian pelts sold totaled 120,465.
Furs from farms now play an important part in the fur trade of both
Canada and the United States. The value of the pelts from farm-
raised animals represents approximately 31 pei*cent of the total annual
value of the raw-fur crop in the Dominion and 20 percent in the
United States.
Abroad, fox farming has had a phenominal development, particularly
in Norway, where the industry has grown like a mushroom. During
the season 1934-35 the number of pelts produced was 103,604. Other
European countries also are producing silver foxes, and in Japan and
South America the industry is well established. The European silver
fox pelts, especially those from Norway, must now be considered an
important part of the world supply. If silver fox farming develops
extensively in South America, the farmers of that continent will have a
seasonal advantage in getting the pelts to the markets, for pelting
there is in July and August.
The world production of silver fox pelts for the season 1935-36
was probably in excess of 500,000 distributed approximately as
follows: United States and Canada, 350,000; Norway, 125*000;
Sweden, 25,000; Netherlands, 5,000; Denmark, 3,000; Union of Soviet
Socialist Republics, 4,000; Germany, 3,000; England, France, Switzer-
land, Japan, and South America together, 3,000.
FUR ANIMALS
1385
It can hardly be doubted that this comparatively new fur-farming
industry has become a permanent part of our agriculture. It has met
with relatively more success in recent years than most other branches
of agriculture, and it promises still greater developments when freed
from the artificial restraints and handicaps that at present are retarding
its progress. Fur farming fits in well as a side line to general farming
Figure 3. — Many small fur farms like this one in Massachusetts are producing fur as
a side line to other agricultural pursuits.
because it can utilize certain parts of the farm not adaptable to
growing other crops. It also provides a winter occupation and brings
in additional revenue during the season when both are needed to
balance farm operations.
In 1926, when the annual production of silver fox pelts in the United
States was about 25,000 and the average price for skins was $126,
farmers began to worry about the possibilities of overproduction.
Many were wondering whether increasing production of furs year after
year would not outstrip even the increased demand, including that
resulting from the normal population increase. At that time the
prices paid for pelts were dropping and the cost of feed was going up.
The situation at that time was more alarming to the small than to the
large producers.
Today, a decade later, the annual crop of pelts has multiplied eight
times, to 200,000. Silver fox fur is fashionable, in fact very fashion-
able. The average price for raw pelts has dropped to $42, only a third
of that realized in 1926. Food costs are increasing rapidly. Some
fox farms have grown bigger, others better. Conditions now are not
perplexing so much to the small as to the large producers. The
reason for this change is that the former does not have all his eggs in
one basket — pelt production with him is a side line (fig. 3). Further-
more, pelt production costs him less on the average than it does the
138904°— 37 88
1386
YEARBOOK, 193 7
large producer and the price he receives for a pelt is on a par with
that obtained by the latter. The small producers as a group are today
marketing more than 140,000 pelts each year, while the large producers
contribute only 50,000 or 60,000 to the annual crop.
Experiments with Other Species
Minks, martens, fishers, skunks, raccoons, and opossums also are
being raised in captivity to some extent, the most striking develop-
ments having been in mink farming. The number of farm-raised
Figure 4. — Skunks are easily raised but not at a profit.
mink pelts has increased rapidly, and the prices paid have been excep-
tionally good, reaching their high point during the 1936 season.
These favorable conditions have naturally stimulated expansion.
Generally speaking it may be said that in the case of fur animals other
than foxes and minks more money is invested in feeding, breeding, and
management than can be realized from the sale of the pelts. For the
present, at least, the production of skunks (fig. 4), opossums, raccoons,
martens, and fishers for fur is not a profitable undertaking.
The problems of the fur farmer are fundamentally the same as those
of other producers of livestock. They include a knowledge of his
animals, their physical needs and temperament, and the requisites
of sanitation, feeding, breeding, and disease control. In all of these
lines, scientific research has a part to play, but so far research has
been of very limited extent.
Present Breeding Methods
During the relatively short period that foxes have been raised by
man no particular strains of outstanding characters have been de-
veloped. The best of them, however, produce fur of high quality.
The problem then becomes one of producing fur of a given character
FUR ANIMALS 1387
and quality with greater certainty. In addition, the fox farmer
would like to be sure of getting good producing vixens in order to
increase his pup crop; and he would like to have greater control of
diseases and parasites, some of which are common to domestic live-
stock and some peculiar to foxes. The disease problem has been
paramount, as the losses on fox farms in certain sections of the country
have been disastrous, in some instances entire ranches having been
wiped out. The application of veterinary science is aiding in develop-
ing the industry, although research has not yet developed methods for
complete protection against several diseases that are causing heavy
losses on fox farms.
The accumulated knowledge developed by plant and animal breed-
ers should be of great value to fur farmers, but the latter have been slow
in applying it to fur-animal production. In the past, time given to
promotional schemes for selling breeding stock to unsuspecting buyers
was much more lucrative than that devoted to the tedious study of
basic principles of fox breeding, feeding, and disease control. Then,
too, the rapid sliift in the market requirements from dark to full silver
pelts has kept the farmers busy — and worried — supplying the demands
of fashion.
In their breeding operations, fox farmers have primarily stressed
the selection of particularly good, true-breeding types and the use
of such animals as breeding stock. Increased prolificacy and the
production of fur of high quality have been the main objectives.
The fur farmer has not advanced so far as the breeder of domestic
livestock in the application of definite breeding principles to his
problems. Among fox farmers in general, there is as yet no idea of
developing a fox strain different from any now in existence and per-
haps possessing outstandingly valuable characters. Such good speci-
mens as have been developed have resulted from continued selec-
tions for a few desired types.
Market Requirements
It must be said, however, that the vagaries of fashion have had a
good deal to do with the failure thus far to set up certain definite
long-time objectives. Forty years ago black fox was popular; a few
years later the highest prices were being paid for quarter and half
silvers; and during the last 4 or 5 years the full silvers have been setting
the upper price limits bocause they are in keen demand for working
into short and long capes, short coats, enormous collars, and wide
trimmings on fur coats, cloth coats, and dresses. In 1936 the prices
obtained in the United States for full silver pelts were 50 percent higher
than in Great Britain.
These shifts in market requirements necessitated strenuous efforts
on the part of breeders to satisfy present demands, with a minimum
of attention to the future. Charles E. Kellogg made an exhaustive
study of the silver-fox-pelt markets of the United States and Great
Britain covering the 5-year period 1932-36 to determine the effects of
trends on the percentages of silver in the pelts. The results showed
that about 36 percent of the American offerings in 1936 were full-silver
skins, an increase of 225 percent during the 5-year period.
1388 YEARBOOK, 1937
This demonstrates how quickly the majority of farmers produced
the maximum of light-silver pelts. Some cautious breeders, however,
are retaining some of the darker silvers in the breeding herd as an
insurance reserve, in case there should be a sudden return to the half
and three-quarters silvers, which are more satisfactory for scarf
purposes. Other breeders feel confident that the genetic make-up of
silvering is dependent upon so many factors that persistent selective
mating toward darker colors would supply such a new demand just
as effectively, though perhaps somewhat more slowly. They feel that
their method permits maximum concentration on full silvers for the
present higher prices. There are no authentic scientific data available
to demonstrate that either method is correct, and thus the producers
continue to be faced with an important problem that for the present
remains unsolved.
RESEARCH IN INHERITANCE IN THE FOX
It is quite generally appreciated that there is still much room for
improvement in the color and texture of silver fox fur. The pelts now
coming to the market are generally somewhat better in quality than
a year ago, but this is true mostly for individual ranches rather than
for sections of the country. Since the number of pelts offered for sale
is increasing year after year, buyers are naturally becoming more
discriminating, especially with the increased competition that now
involves other countries as well as the United States. Fox fanners have
reached the point where they must exert every possible effort to im-
prove the quality of the fur produced. For the present, close culling
of the breeding stock, which means pelting the undesirables, and in-
telligent and strict selection of breeding animals are the most certain
methods to bring about a marked improvement in fur quality.
To meet the need for fundamental information on the genetic basis
of silvering, the Biological Survey began an experiment in 1935 at the
United States Fur Animal Experiment Station, at Saratoga Springs,
N. Y. An attempt is being made to determine, if possible, the genetic
factors involved, so that market requirements can be met more
promptly. The objective is to determine the relationships between
the various degrees of silvering and to work out methods of breeding
that will enable the breeder to have more control over them. Only a
small number of foxes is available for this experiment, whereas ex-
perience proves that a large number must be used to obtain definite
results where many genes are concerned. There has been only one
other research program to trace the inheritance of fur colors, and this
was concerned not with gradations in silvering but with the basic
differences between red, cross, and black (silver) foxes. To make this
clear, it is necessary to give a brief account of these different types.
Before the development of fox fanning, there apparently occurred
in the common red fox (Vulpesfulm) two distinctly different mutations
to black. One of these, namely, that to which the standard or Prince
Edward Island silver fox traces its origin, must have occurred some-
where in Canada, probably in the eastern or central part. The other,
to which the Alaskan silver fox traces its ancestry, certainly must have
occurred in Alaska, most likely in the interior. The so-called cross
fox was probably produced by crossing the red and the silver (fig. 5).
FUR ANIMALS
1389
Thus foxes of the genus Vulpes may have three kinds of pelts: (1)
The common red fox, which is primarily red or fulvous with a mixture
of gray or brown except for restricted black markings on the feet and
ears, a white area at the end of the tail, and certain white-banded
hairs on the back and rump; (2) the typical cross fox, in which black
predominates on the feet, legs, and under parts, while red or fulvous
overlying black covers
most of the head, shoul- ^
ders, and back; and (3)
the black (silver) fox,
which carries no red or
fulvous, the entire pel-
age being dark at the
base and heavily or
lightly overlaid with
the banded guard hairs
that produce the
silvery appearance.
These guard hairs are
not entirely white but
are black with a white
band, and some are en-
tirely black. Foxes of
the third group vary
from animals that are
almost entirely silver
to those that are en-
tirely black except for
a few white-banded guard hairs on the back and rump. The fur trade
recognizes five classes of silver fox pelts, graded according to the per-
centage of silver, as follows: Full, three-quarters, half, one-quarter,
and slightly silver or dark.
It is believed that what are called standard silver foxes, carrying
a factor for silver and black color, were found naturallv in many parts
of Canada. Few if any of these foxes migrated into Alaska. On the
other hand, the progeny of Alaskan silver foxes, also carrying a factor
for the silver and black color, probably traveled southward over the
mountain range and spread over a large part of Canada, Neither the
Alaskan nor the standard silvers migrated to any extent south of the
Great Lakes and the St. Lawrence River. The indications are,
however, that some foxes possessing either or both of these factors
for silver and black must have migrated or occurred naturallv south
into the northern parts of the States bordering on the Great Lakes.
In the early days of fox fanning, red and cross foxes captured in the
wild were bred to produce silvers. As more silver foxes became avail-
able, they replaced the red and cross foxes on ranches, and silver foxes
were bred together to produce silvers. As time went on foxes that
woidd breed true for silver were developed and it became generally
understood that silver foxes produced from silver fox parents would
always breed true, Later on, however, when silver foxes originating
in Canada were bred to silver foxes from Alaska, the young produced
proved to be crosses and not silvers.
Figure 5.-
-Litter of pups resulting from cross-breeding
a silver with a red fox.
1390 YEARBOOK, 1937
Genetic Relationships Between Red, Cross, and Black Foxes
Prior to 1928 no scientific research had been conducted to determine
the genetic basis of the red, black (silver), and cross coloring in foxes,
and consequently there was considerable confusion as to the genetic
relationship between the black color in standard and in Alaskan foxes.
In 1928 it was decided to include such studies in the program of
research for the United States Fur Animal Experiment Station.
B. L. Warwick, of the Texas Agricultural Experiment Station, coop-
erated with the late Karl B. Hanson, of the Pur Animal Station, and
proposed a hypothesis that would account for the results obtained.
To clarify the discussion somewhat, this hypothesis will be given first.
Warwick suggested that genes A and B and their alternative forms
(alleles) a and b account for red, black (silver), and cross colors in
foxes. All the possible combinations of these genes would give the
following types:
AABB-= Alaskan red. -<4j4£&-= Smoky red.
A Abb ■= Standard blacl;
AaBB-= Cross. AaBb*= Blended cross.
(silver) .
aaBB-= Alaskan black aaBb-= Sub- Alaskan black
Aabb-= Substandard black.
(silver). (silver).
aa&b= Double black.
Hanson found that when the standard black and the red foxes were
crossed, the offspring were usually a smoky red. Although red was
strongly dominant to black, it was not completely dominant; there
was some blending that produced the smoky color. Foxes of the
first filial generation had larger prominent dark points and more
evidence of black than is usually present in the red parents. Segre-
gation into reds; smoky reds2 and blacks occurred when the first-
generation offspring were bred inter se, that is, bred to their own kind.
The ratio of segregation was about 1 red to 2 smoky red to 1 black.
When smoky red foxes of the first filial generation were backcrossed
to the black parents, the result was a ratio of 1 smoky red to 1 black.
These ratios indicated that a single gene accounts for the difference
between pure standard blacks and reds.
On some fox farms, however, where supposedly pure standard black
foxes were bred with pure red ones, mixed litters of smoky reds and
reds in about equal proportions were produced in the first generation.
Doubtless the black (silver) parents were not pure but had a hybrid
combination of the genes A and a.
Some red foxes caught in the wilds of Canada, the Upper Peninsula
of Michigan, and northern Minnesota and Wisconsin when crossed
with pure standard blacks produced mixed litters, with blacks and
smoky reds in equal proportions. If these wild red foxes were really
hybrids or smoky reds, it would account for the results.
When Alaskan blacks were crossed with red foxes, the first genera-
tion were all cross foxes, but no appreciable dominance of black or
red was in evidence. When the first filial generation was bred inter
se, there was a segregation of 1 red to 2 cross to 1 black (silver). The
cross foxes when backcrossed to black parents again produced crosses
and blacks in equal prpportions. The ratios again indicated a differ-
ence of one gene between pure red and pure Alaskan silver foxes.
Hanson then crossed Alaskan and standard black (silver) foxes.
The first filial generation turned out to be blended cross foxes. This
FUR ANIMALS
1391
KEY TO GENETIC TYPES
PURE BREEDING
PARENTS (Pi)
HYBRID PROGENY (Fi)
OF PURE BREEDING
PARENTS
SECOND GENERATION (Fa)!
OF HYBRID PROGENY
6RED INTER SE
BED
SMOCKY
HEO
A/IBb
STANDARD
BLACK.
slAbb
ALASKAN
RED
CROSS FOX
BLENDED
CROSS FOX
SUB-
STAN DABD
BLACK
ALASKAN
BLACK
rrrr/lH
SUB-
ALASKAN
BLACK
DOUBLE
BLACK
MATINGS
m h m h
12 3 4
H a a H
10
m m m
12 |.|-,i, i 13 14
15
CROSSING FiTO PURE
BREEDING Pi TYPES
CROSSING Fi TO OTHEr(
Pi TYPES J
16 | | | I 17 18 nil! 19 20 | hM 21 22 ■ ■ ■ ■ 23
H ff§" fflffil
24 25 26 27
LSrSMBMffl
28 29 30 31 32 33 34 35
OTHER. POSSIBLE
MATINGS
HB 36 EBB Erfl
38™ I I 39rrn 4otjEi
37
41
42
I B I
43
m
THT
44
IHLl
45
Figure 6. — Diagram illustrating the genetic types of foxes and the results of various
matings on the basis of a two-factor inheritance. Black squares represent matings,
and numerals wilhin the squares represent the expected distribution of progeny
in proportions.
1392
YEARBOOK, 193 7
Figure 7. (Legend on opposite page)
FUR ANIMALS 1393
indicates that two different genes are involved in Alaskan and standard
black foxes.
In some instances when Alaskan blacks and standard blacks were
mated, black young occurred in the litters. Check matings demon-
strated that the occurrence of black in the first filial generation was
due to the fact that one or the other of the parents was not pure but
hybrid for either A or B.
Inadequate facilities and lack of funds made it impossible to main-
tain a sufficient number of foxes at the Fur Animal Station to make a
complete investigation of this kind. Therefore, the research workers
had to solicit the cooperation of fox farmers who had been conducting
cross-breeding experiments in the United States and Canada. They
willingly furnished the data obtained from their breeding operations,
and these proved to be most valuable in amplifying the results ob-
tained at the experiment station.
Hanson made a biomctrical analysis of these data and found that
three principal colors in foxes are inherited in accordance with the
factor hypothesis previously mentioned. In 775 litters, including
over 3,000 pups, representing 30 different combinations of types,
only 4 litters were reported in which the results were contrary to the
hypothesis. In at least two of these cases there was some doubt as
to whether the vixen was served by two different males or whether
the parents were improperly classified as to color.
Hanson designed a chart to illustrate the results of the various
matings on the basis of two-factor inheritance (fig. 6). At the top of
this chart is a key to the three different colorings and the nine different
combinations of genes that result in nine different types. Directly
under the key is a series of smaller nine-block squares giving the 45
different mating combinations of these nine types. The black squares
in the blocks represent the genetic types mated and the numerals
represent the expected distribution of progeny in proportions. Refer-
ence should be made to the key at the top of the chart to determine
the colors (fig. 7) and genetic make-up of the animals being mated
and also the progeny.2
As examples of the use of the chart: Suppose Alaskan blacks are to
be mated with standard blacks. This mating is given in the set of
* In matings producing more than one kind of progeny the result may deviate in the distribution of progeny
in individual litters or in a small number of litters, not only among foxes but among other animals also.
For example, the expectation from crossing a substandard black with an Alaskan black (fig. 6, square 32)
is that the progeny will consist of blended crosses and sub-Alaskan blacks in a 1: 1 (50:50) ratio. As likely
as not, this mating will produce an equal number of crosses and blacks (silvers) . The probable occurrence
of different combinations of cross and black foxes in litters of four thus produced is as follows:
Black (silver) foxes ~~ 4-3-2-1-0
Cross foxes 0-1-2-3-1
Total 4-4-4-4-4
Although these figures represent the proportion of black (silver) and cross foxes that may occur in litters
of four, litters of that size do not always occur. In sufficient numbers there would be produced six times
as many litters containing equal numbers of silver and cross foxes as there would be litters of all silvers or all
crosses. Likewise the litters with three pups of one color and one of the other would be produced four
times as frequently as would be litters of all one color.
Figure 7. — Fox pelts of the nine genetic types, upper and under side illustrated in
each case, and grouped as in the square diagram in figure 6: A, Red, AABB; B,
smoky red, AABb; C, standard Mack, AAbb; D, Alaskan red cross fox, AaBB; E,
blended cross fox, AaBb; F, substandard black, Aabb; G, Alaskan black, aaBB;
H, sub-Alaskan black, aaBb; I, double black, aabb.
1394 YEARBOOK, 1937
squares numbered 9. The figure 1 in the middle square indicates that
all the progeny will be blended cross foxes. Now suppose these
blended cross foxes are bred together, as in the set of sqiiares num-
bered 15. The figures in the squares indicate that every kind of fox
will result from these matings, and that in a large number of matings
the proportions may be expected to be 4 blended crosses, 2 Alaskan
red crosses, 2 smoky reds, 2 substandard blacks, 2 sub-Alaskan
blacks, 1 red, 1 standard black, 1 double black, 1 Alaskan black. If
an Alaskan black is mated with a smoky red, as in the set of squares
numbered 31, the result will be 1 Alaskan red cross to 1 blended cross.
If a sub-Alaskan black is mated with an Alaskan red cross, as in the
set of squares numbered 41, the result will be equal numbers of
Alaskan red crosses, blended crosses, Alaskan blacks, and sub-Alaskan
blacks.
A SUGGESTED PROGRAM EOR FURTHER RESEARCH
Fur farmers look to the scientist for leadership in the development
both of basic information in fur-animal breeding and of methods of
improvement, and they have appealed many times to the Federal and
State Governments for assistance. Little has been done, however,
by public agencies to develop this new and promising animal-produc-
tion enterprise, and there has been no systematic effort on the part of
State agricultural experiment stations or the Department of Agricul-
ture to develop, isolate, perpetuate, or record fur animals of superior
breeding ability.
In order to place fur farming on a foundation comparable with that
of other branches of agricultural production, fundamental knowledge
is essential, and this can be obtained only by inaugurating a compre-
hensive program of research. Such a program might be conveniently
divided into three parts:
1 . Research work on reproductive cycles. Most of the study thus
far has been concerned with domestic species, and the available definite
information on wild animals is very meager, particularly as regards
species of economic importance. A more exact knowledge of the
reproductive cycles of North American fur animals could be applied
in several ways. It would be of great value — (a) in determining the
proper trapping seasons for restoring and conserving fur animals; (b)
in attempting intelligently to supplement the natural supply by restor-
ing and transplanting; (c) in insuring success in producing- fur species in
captivity; and (d) in making possible a more efficient and economical
control of predatory and other injurious species. The object of
research on reproductive cycles would be to establish definitely — (a)
the breeding period of valuable fur animals ; (b) the number of litters
and young produced yearly; (c) the type of embryonic development
(whether uninterrupted or with a delay in implantation); (d) the
hormone control of the breeding cycle; (e) the feasibility of artificial
insemination in those species that might be raised in captivity; and
(f) possibilities for producing or maintaining reproductive fertility by
hormone or other treatment.
2. Breeding experiments with various fur animals under controlled
conditions. These should be conducted to study the inheritance of
prolificacy and fur quality, which includes color, sheen, and density.
FUR ANIMALS 1395
In all animal breeding it is vital to concentrate on as small a number
of objectives as possible. Measurements must be devised to evaluate
all these characteristics with greater certainty, especially fur quality.
Similarly, there should be measurements for efficiency of feed utilisa-
tion, since the cost of feeding is a large part of the cost of production.
Where genetic factors (genes) might be directly useful, as in the case
of coat colors, they should be determined so far as possible. They will
doubtless prove to be extremely complex, but the research on color
inheritance already described indicates that something may be done
to segregate definite traits of this kind and to breed for them. Mean-
time, to use breeding stock of proved performance, as determined by
the progeny test and by dependable records of parental characteristics,
would be to approach the problem in the way that has proved to be
of such great value in other branches of livestock breeding.
3. Attention to nutrition. Tliis article is concerned primarily with
breeding and genetic research, but in any comprehensive research
program, nutrition is equally important. Practically no fur-animal
research studies have been conducted on digestion and metabolism,
the chemical composition of foods, and the part played by various
foods in growth, fattening, maintenance, reproduction, and the eco-
nomical production of pelts of high quality. With few exceptions,
all fur animals are meat eaters. The maximum and minimum quan-
tities of red meat that can be fed during the various stages of develop-
ment should be determined. Some work has been done to determine
the value of cereals, vegetables, and protein supplements in the ration,
but it should be expanded. These and many more nutritional prob-
lems when adequately solved will enable fur-animal breeders to
proceed more surely, safely, and efficiently.
Without extensive controlled experimeuts, all breeding and feeding
practices are of a hit-or-miss nature. But experiments with fur
animals are exceptionally costly, not only in the matter of equipment,
but also in the time involved, for breeding stocks are expensive and
practically all species produce only one litter a year. In addition,
scientific training and the ability to conduct research are required,
and the economic results of any given project are by no means certain.
Private breeders therefore are not likely to do much experimenting,
because they must confine themselves to operations that are fairly
certain to produce immediate profits. Fur-farmers' organizations or
wealthy producers might undertake some forms of research work, but
men change their minds and associations change their policies, and
under these conditions there is no assurance of continuity. There are
many reasons why fur-animal research must be conducted primarily
by properly equipped public institutions, but this can be done only
in response to a sufficient public demand and with the active support
of those who have a stake in the industry.
BEE BREEDING
W. J. NOLAN, Apiculturist, Divi-
sion of Bee Culture, Bureau of
Entomology and Plant Quarantine
A HE economic importance of bee breeding, measured in dollars, is
probably greater than is realized even by the beekeeper. The poten-
tial stake of agriculture in the United States in queens alone is over
$2,000,000, if a value of 50 cents, the minimum price set by the market-
ing agreement governing the sale of queens, is placed on each of the
Figure 1. — The three inhabitants of the hive: A, The worker, a female with arrested
development of the egg-laying organs; B, the queen, a female with completely devel-
oped egg-laying organs but with undeveloped secondary sexual characters such as
those possessed by the worker for secreting larval food, for gathering nectar and pollen,
for secreting wax, and the like; C, the drone, the male bee. During the height of the
season, a bee colony may consist of several thousand workers and a few hundred drones,
but it normally contains only one queen at any time.
queens in the more than 4,000,000 colonies of bees in this country.
The amount invested in bees, hive and honey-house equipment, and
the like is $35,000,000 to $50,000,000 on the conservative basis of $8
to $12 per colony. Whether a fair return is being received by the
beekeeper on these sums, plus the amount involved for his time and
labor, depends primarily on the blood represented by the queen and
by the drone with which she mates (fig. 1).
The public is also directly affected by the breeding problem, not
merely from the standpoint of being insured an abundant supply of
honey, but from the more important standpoint of having bees that
will function as efficiently as possible in the pollination of many of
1396
BEES 1397
our crops. For example, clover crops, which are so fundamental in
the dairy and livestock industries, apples and other fruits, and truck
crops in greenhouses are now more or less wholly dependent on the
efforts of the honeybee. There is interest also in increasing the supply
of native beeswax, which at present comes so far short of meeting
domestic demands that large quantities are imported annually. The
bee is far more valuable to American agriculture through all these
other activities than through its honey production. As a matter of
fact, the activities of the honoybee are so varied and so useful that
practically every person benefits by them in some way or other, and
so will benefit, indirectly at least, by any improvements that result
from scientific breeding.
FACTORS LIMITING PROGRESS OF THE BEE BREEDER
In spite of its importance, bee breeding is only in its infancy, one
reason being that promising methods for mating queens and drones
under laboratory conditions had not been worked out until within the
last few years. Prior to the development in 1923 of the Quinn-
Laidlaw technique — discussed later in this article — whereby, through
the agency of the operator, the drone organ is everted in proper posi-
tion in relation to the queen for insemination to take place, and in
SEVERAL desirable characters have been commonly recognized
among the varieties of honeybees used in the apiary, but the breeder
during past years has been able to do little in combining these in
one bee because in nature queen and drone mate only on the wing.
These characters have to do with disease resistance, color of comb
cappings, size of body parts, constancy of color markings, disposi-
tion, and swarming propensity. Because of recent work that shows
the feasibility of accomplishing the insemination of queen bees by
laboratory methods, the breeder is now in a position, however, to
utilize the characters already available in the germ plasm of bees
and to start at once toward the goal of breeding bees better adapted
to present agricultural demands. It would be a great and perhaps
not impossible achievement to breed a bee with the long tongue of
the Caucasian, capable of reaching sources of nectar not now avail-
able to most honeybees; the gentleness of the Caucasian and the
Carniolan; the white comb capping made by the black bee and the
Camiolan; the reduced swarming tendency, and the resistance to
common hive enemies and European foulbrood, of the Italian; the
uniform marking of the Cyprian; and the industriousness of the
Italian or Cyprian.
1398
YEARBOOK, 1937
1926 of the Watson technique for the artificial insemination of queen
bees through the transfer of sperm from drone to queen by means of a
microsyringe (fig. 2), the bee breeder was forced to trust to luck in
his work, because he had to rely on chance natural matings in midair,
since in nature the honeybee mates only while on the wing away from
the hive. A successful method for obtaining natural matings of
queen and drone in confinement still remains to be developed.
Another reason for the back-
wardness of bee breeding is the
fact that only since the application
of biometric methods in studying
the body parts of individual bees,
a development of recent years, has
progress been made in working out
a method whereby the breeder
can readily identify the race or
strain with which he is working.
Mendel, the father of modern
genetics, lacked a means of dis-
tinguishing between strains when
he endeavored to work out prob-
lems of bee genetics in addition
to those of the genetics of peas,
which brought him fame (9, pp.
142-157).1
The first investigator to make
a comprehensive biometric study
of the honeybee was Kozhevnikov
(12), who in 1900 endeavored to
separate the various races on the
basis of physical measurements made with the aid of a microscope.
He included such measurements as hooks on the wing, tongue length,
length of leg segments, length of abdominal segments, length of wings,
and the like. Since that time Russian investigators have been
particularly active in this field.
However, the problem of checking differences between various
crosses, strains, and races of the honeybee on the basis of the physical
characteristics of individual bees, or even of the productivity of
colonies, and then utilizing the results in breeding, is far more com-
plicated than with other farm animals. This is due not only to the
small size of the honeybee, but also to the fact that honeybee pro-
ductivity represents the collective efforts of the thousands of individ-
uals making up a colony. It is even hard to define a standard colony
for purposes of any comparative experiments, since, even under the
same natural conditions outside the hive, within the hive the physio-
logical ages of the individual bees differ. Furthermore, the honeybee
cannot carry on its life functions indefinitely ha confinement, as can
cattle, poultry, rabbits, or even pigeons.
Advances in scientific bee breeding are also limited by the variety of
demands on the breeder. Queens must be reared and tested; drones
must be reared; mating of queen and drone must be accomplished;
1 Italic numbers in parenthesis refer to Literature Cited, p. 1537.
Figure 2. — L. R. Watson, who developed
the Watson method for the artificial in-
semination of queen bees, seated at his
instruments.
BEES 1399
progeny must be tested for colony characteristics and production, as
well as for physical characteristics of individuals; and results must be
evaluated. The scientific breeder should possess a working knowledge
of the biology of the honeybee, including an intimate knowledge of its
various races and strains, and of genetics, biometrics, and supple-
mentary fields as well. In short, he should be a combination bee-
keeper, laboratory technician, biometrician, and geneticist, or know
bow and where to utilize the services of specialists in the various fields
involved.
Another situation faced by the bee breeder is the fact that worker
bees cannot be bred, and the queen and drones, mating but once in a
lifetime, cannot be used in line breeding involving parent-offspring
crosses. Furthermore, since queen and drone function only in
reproduction, progeny tests — in other words, the collective colony
behavior exhibited by the worker progeny — must be relied upon
exclusively in testing the inheritance of the queen and drone for such
economically important characters as honey gathering, wax secretion,
pollinating activity, and the like. Even when a parent queen is
bred pure for the same color factors as the drone with which she mates,
her color pattern may differ from that of her worker daughters, since
in some races, the Italian being one, the causes that lead to the
development of worker structures in a larva, with a resultant arrest
in the development of its reproductive organs, also lead to a modifica-
tion of its color pattern.
MORE KNOWLEDGE REGARDING REPRODUCTIVE
PROCESS NEEDED
The advantageous employment of present mating methods, or their
improvement, whether natural or artificial insemination is involved,
will be facilitated when the physiological processes preceding and
accompanying mating are better understood, since much remains to
be known regarding the conditions most favorable for mating. For
example, the consensus of opinion is that the queen mates when about
a week old or shortly thereafter, but a queen 56 days old has been
artificially inseminated with success. A knowledge of the external
signs, if there are any, that queen and drones are ready for mating
should go far in increasing the usefulness of methods of artificial in-
semination and also be of advantage in work involving natural in-
semination.
As a matter of fact, until recent years little was known about repro-
duction in the honeybee. Knowledge that drones are produced from
unfertilized eggs (parthenogenesis), at least in European varieties of
the common honeybee, dates only from the middle of the last century,
and the origin of queen and worker and the fact that the queen mates
on the wing outside the hive has been known for only about 150 years.
More has been done in studying the mating processes in the drone
than in the queen. The most complete study on the drone is that by
Bishop (4), who found that usually the drone is not sexually mature
until the ninth to twelfth day after emergence, but that some drones
are apparently incapable of mating at any age. Bishop also found the
function of the mucus, which the male organ contains in addition to
sperm. During mating the sperm is merely transferred from the
1400 YEARBOOK, 1937
drone to a temporary storage place in the vagina and oviducts of the
queen. The spermatozoa collect within the spermatheca during the
next few hours and may live there for 6 years or more. While still
in the oviducts and vagina, however, the sperm might all escape
through the genital opening were not this opening filled with the
mucus from the drone when the last of the sperm has entered. This
mucus quickly hardens on exposure to air, and thus forms a tem-
porary stopper in the genital opening.
The anatomy and the physiological responses of the queen in rela-
tion to mating are being studied by Harry Laidlaw, formerly in the
employ of the Department but now a graduate student at the Uni-
versity of Wisconsin. This study includes the structure and func-
tioning of the queen's genital organs, a subject on which little is
known, but a knowledge of which is demanded for the further success-
ful development of methods, not only of artificial insemination but
even for obtaining natural matings in confinement. Laidlaw has
found that a membranous fold arising from the floor of the vagina
fits so snugly in the genital passage as to be able to thwart attempts
to inseminate queens artificially by his method or perhaps sometimes
to defeat efforts to insert the glass syringe by the Watson method.
MATING STATIONS AN EARLY STEP IN THE
BREEDING PROGRAM
In spite of many handicaps, the bee breeder has not been idle.
During the period when he was attempting to bring the mating of the
honeybee under laboratory control, he made such use of natural mat-
ings as he could by establishing mating stations in isolated bee-free
localities, taking virgins and drones of desired stock there to mate.
The possibility, however, that the queen may mate with a stray
drone, even in a locality thought to be well isolated from local bees,
reduces the value of mating stations in a scientific breeding program.
The first reported use of isolated localities in an endeavor to obtain
pure matings of bees was that by Baldenstein (2 ) in Germany in 1848.
Breeders in a number of European countries are now carrying out
investigations by means of bee-mating stations. In Switzerland the
association of German-speaking beekeepers has for a number of
decades conducted a well-supported movement, inaugurated by the
Swiss beekeeping leader Kramer, to maintain and improve the native
Swiss bee by having selected queens mate in isolated localities at
stations stocked with drones of desired strains. The mating stations
are in charge of personnel from the beekeepers' association. Bee-
keepers bring virgin queens or queen cells in mating nuclei to these
stations and take back the mated queens. The method resembles the
use of community-owned sires in cattle breeding.
On this side of the Atlantic such stations have not been used so
much in scientific investigations. The notable exceptions are the
breeding experiments conducted a number of years ago in Texas by
Newell (21), and those by Sladen (84), of Canada, in progress on an
island in Lake Ontario at the time of his death in 1924. Even com-
mercial queen rearers have made little use of mating stations, because
in this country isolated locations free from wild swarms or colonies
of neighboring beekeepers are not easily accessible to most queen
BEES 1401
rearers. In Colorado, however, a strain of the Caucasian race was
maintained for at least 25 years through natural matings in an isolated
locality (1, p. 40). Certain commercial queen rearers in this country
have attempted insofar as possible to duplicate conditions found in
an ideal mating station by endeavoring to rid the territory in the
immediate vicinity of their mating yards of undesirable colonies of
bees. Their methods have consisted of buying up colonies found in
the neighborhood, requeening colonies nearby with desired stock
free of charge, paying rewards for wild swarms, and similar measures.
OBJECTIVES OF THE BEE BREEDER
What are the immediate objectives of the bee breeder? He may
attempt to standardize the various strains now existing that are of
economic importance. He may even attempt to develop strains
that are more gentle, more disease-resistant, capable of carrying
larger honey loads, or capable of flying longer distances than strains
now available. He may attempt to develop strains with tongues
long enough to secure nectar from floral sources not now available
to the honeybee. For some regions it would seem desirable to develop
strains that fly at lower temperatures than do bees now commonly
found in the United States. This is of particular importance to
those interested in bees as pollenizing agents.
The breeder need not await the occurrence of mutations, or an
exhaustive survey of existing strains, to find some definite character
of economic importance with which to begin work. On the contrary,
he is able to start at once toward his goal, a bee better adapted to
present agricultural demands, since not one but several desirable
characters have already been identified among the varieties of honey-
bee now used in the apiary. Other desirable characters may exist,
while still others are to be expected from futiire mutations occurring
either naturally or under experimental conditions.
What are the characters in the available germ plasm with which
work may be begun immediately? They are related to disease
resistance, color of comb cappings, size of body parts, constancy of
color markings, disposition, swarming propensity, and the like. For
instance, the breeding of a bee in which are incorporated the long
tongue of the Caucasian, the gentleness of the Caucasian and the
Carniolan, the white capping made by the common black bee and
the Carniolan, the reduced swarming tendency and resistance to
common hive enemies and European foulbrood of the Italian, the
uniformity of marking of the Cyprian, and the industriousness of
the Italian or Cyprian would be a big achievement. Some commonly
accepted worker characters, desirable and undesirable, and the races
in which they are found are given below:
Character Race
Resistance to European foulbrood Italian.
Fighting wax moth Italian, Cyprian.
Hive cleanliness Italian.
Clinging to frame during manipulation Italian, Cyprian.
Running on frame during manipulation Common black, European brown.
White cappings on honey Common black, European brown,
Carniolan.
Water-soaked cappin gs Cyprian.
138904°— 37 89 ++
1402 YEARBOOK, 193 7
Character Race
Tongue length over 6.75 mm Caucasian.
Tongue length under 6.25 mm Common black, European brown;
Long legs Caucasian.
Uniformity of markings Cyprian.
Yellow scutellum Do.
Gentleness Caucasian, Carniolan.
Viciousness Cyprian.
Reduced swarming tendency Italian.
Excessive swarming Common black.
Propolizing tendency Caucasian .
BEE BREEDING IN THE UNITED STATES
Investigations of the Department of Agriculture
The Department of Agriculture was a pioneer in providing the
American beekeeper with new breeding stock. It began this work by
bringing in bees from Europe in an effort to have better blood than
Figure 3. — Multiple set-up devised in the Department of Agriculture for inseminating
each equipped with a microsyringe and apparatus to hold the queen during the opera
that represented by the common black bee, introduced about the
middle of the seventeenth century, and as a result is credited with
having established the Italian race in the United States through
importations made in 1860.
In 1905 the Department sent a specialist around the world, pri-
marily to secure the introduction of Apis dorsata Fab., the largest
honeybee known, but the effort was unsuccessful. At that time the
Department was distributing queens of the Cyprian, the Carniolan,
and, more especially, the Caucasian race. During the last few years
it has given further attention to a study of various races. As a result
of this work and observations made by beekeepers in general, the
recommendations of the Department as to an all-around bee for tins
country, for anyone other than the bee specialist or fancier, are usually
limited to the Italian or Caucasian race.
The Department also led the way in this country in attempts to
develop methods for the artificial insemination of queen bees. As
early as 1885, the date when it employed its first full-time specialist
BEES 1403
in beekeeping, it set forth as one of his duties: "To make experiments
in the methods of artificial fertilization and, if possible, demonstrate
the best process by which the same may be accomplished." Some
slight success was reported from this early venture, and a method
described in which a fine-pointed syringe was employed, as in the
present Watson method, but this early work was not followed up. In
1907 the Department conducted unsuccessful attempts to obtain the
mating of queens on the wing within enclosures.
Within the last few years the Department (23) has greatly simpli-
fied the technique and equipment for the Watson method, reducing
the cost of equipment and making it possible to operate on several
queens more or less simultaneously, thus increasing the output (fig. 3).
Some of the special features of this new equipment differentiating it
from that developed by Watson are as follows: Only one microscope
is needed in using a large number of syringes; a cheap and easily made
manipulator is provided for the microsyringe; the queen is held in a
several queens more or less siimil taneously. The set-uj) shown consists of 6 separate units,
tion. One microscope serves the entire set-up, being moved from unit to unit as needed.
glass tube with only her abdominal tips projecting, instead of being
bound by thread to a small wooden block hollowed out to fit her body;
and the queen's abdominal tips are spread apart by a pair of metal
hooks held mechanically instead of by forceps held by hand (fig. 4).
With this equipment the genital opening of the queen can be found
quickly under the miscroscope, and the microsyringe then can readily
be brought into correct position for discharging the sperm without
injury to the queen.
A durable microsyringe, all metal except for the minute plunger
tube of glass that holds the sperm, has been developed from an auto-
matic pencU by substituting a fine wire plunger for the lead and attach-
ing the plunger tube to the point of the pencil. The earlier syringe
consisted of a piece of glass tubing drawn out to proper shape for
holding the plunger and plunger mechanism, as well as for attaching
the plunger tube.
Sperm to fill the syringe is obtained by causing partial eversion of
the drone organ by pressure on the drone, after which the bulb con-
1404
YEARBOOK, 193 7
taining both sperm and mucus is pulled loose with a pair of forceps.
With the bulb still held in the forceps, the end containing the white
mucus is cut away and the remainder, forming a minute sac contain-
ing the cream-colored sperm, is slipped over the point of the syringe.
The sperm is then drawn into the plunger tube.
The Department has also modified the Quinn-Laidlaw method for
artificial insemination, commonly referred to as a "hand-mating"
Figure 4. — Separate unit of the multiple set-up, showing queen and niierosyringe in
position. The microsyringe differs somewhat in construction from the original Watson
type but works on the same principle. A less fragile microsyringe, all metal except
for the glass point and with the movement of the plunger in and out caused by direct
action, has since been devised in the Department.
method, by using a glass tube to hold the queen and a small spring
placed inside her abdominal tips to hold them apart (H). A micro-
scope is now used during the process. As when the method was first
developed, the drone is so held by hand as to cause partial eversion
of its genital organs and is then so placed in relation to the queen that
the transfer of sperm will be accomplished after complete eversion
has taken place.
Biometric data on common races of the honeybee and on the
progeny of various crosses made by controlled ma tings are being
collected by the Department to determine racial or strain characters
of a quantitative nature and their behavior in crosses. The data
collected so far consist mostly of linear measurements of various
parts of the head, thorax, and abdomen. The specimens are mounted
on slides under a microscope and the measurements are made on
projected images (fig. 5). Those of head parts (fig. 6) include
BEES
1405
tongue and scapus (the long joint of the antenna). On the thorax
they cover counts of hooks on the hind wing and dimensions of the
fore wings (fig. 7, ^1) and hind legs (fig. 8). On the abdomen the
measurements deemed important are width of the third tergum (the
upper surface of the third segment), longest width of third sternum
(lower surface of third segment) across its left wax plate, and longest
dimension of the wax
plate itself. The first
two abdominal seg-
mcnts, because of their
shape and lack of wax
plates, do not lend
themselves to such
measurements (fig. 9).
The size of the fore-
going parts is of eco-
nomic interest as well
as of value in distin-
guishing races or
strains, because nearly
all of them function
directly in the gather-
ing of nectar and pollen
and in the production
of wax. The tongue,
for instance, is of im-
portance in nectar
gathering. The wings
are important in all
activities taking the
bees away from the
hive. The hind legs
carry pollen. The ab-
dominal segments con-
tain the wax plates,
and may serve to limit
the size of the honey sac.
Characters of a quali-
tative nature are also
being studied. These include gentleness, industry, disease resistance,
and the like. At the present time the Department is engaged in a
cooperative undertaking with the States of Iowa, Texas, AVisconsin,
and Wyoming, to search for stock resistant to American foulbrood,
and then to combine the factor for resistance, if any be found, witli
other desirable factors by breeding.
During the past year the Department has employed a trained
geneticist for the first time in its beekeeping work. His immediate
genetical problem is to determine whether heritable factors affect
supersedure, especially the premature supersedure of queens sold
commercially. By "supersedure" is meant the replacement of the
queen by another reared by the colony apparently for that purpose.
Figure 5. — Apparatus used in the Department of Agri
culture for measuring external parts of bees. A microm-
eter eyepiece with a movable scale is attached to the
microscope.
1406
YEARBOOK, 1937
If heritable factors play a part in this behavior, they may lie in the
behavior of the queen alone — lack of fecundity, for example — or
they may lie in the behavior of the workers — for example, undue
hostility to a queen reared in another colony.
State Bee-Breeding Work
Only a few States have been engaged in breeding work. A number
of years ago Shafer (80), at the Michigan Agricultural Experiment
figure 6.— A, Head of bee, showing: a, Antenna; b, gena; c, clypeus; and d, labrum.
longue is shown extruded but cut off. B, Extended tongue, showing: a, Submen-
turn; b, mentuiu; c, ligula; and d, labial palpus. (Drawing by Snodgrass.)
Station, made an unsuccessful attempt to obtain controlled matings
of queen bees by natural insemination. The New Jersey Station
conducted bee-breeding work in an isolated location for a number of
years in connection with a study of disease resistance. More recently
the Iowa Station, in cooperation with the American Bee Journal,
has been engaged in a program to find stock resistant to American
foulbrood and to breed for this character. The Texas Station is
endeavoring to breed a bee that will better withstand Texas weather
and possess greater honey-gathering ability than present strains . The
College of Agriculture of the University of California is studying the
correlation between physical characters of queens and their produc-
tivity, and is also studying environmental factors that influence the
development of queens. The College of Agriculture of the University
BEES
1407
of Minnesota a number of years ago conducted work on the artificial
insemination of queen bees by the syringe method, with some slight
success. In this work, performed by Jager and Howard (10), the
sperm was diluted with salt solution.
Merrill (1 6), while in charge of apicultural work at the Kansas
State Agricultural College, became the American pioneer in the bio-
metric study of the activities of the colony as a whole. He attempted
to correlate honey production with tongue length, size of honey sac,
and other physical
characters. A few years ff
ago Munro (19), while ~t~
a student at this college,
made a study of color
inheritance, using nat-
ural matings. At pres-
ent E. J. McNay, a
graduate student at
the same institution, is
making use of the
Watson method in
breeding work.
Work by Private
Breeders
The outstanding bee-
breeding work of a pri-
vate nature is that by
Watson (36, 37), who
developed the method
for the artificial inse-
mination of queen bees
that bears his name,
and who now holds a
Guggenheim fellowship
for the study of bee
breeding. He is making a survey of tongue lengths of various strains
in an endeavor to develop a longer tongued bee than is now available.
He is also trying by artificial insemination to perpetuate the "Albino"
bee, a mutation of the Italian that appeared in this country about 50
years ago but has now apparently disappeared except for stock in
Watson's apiary. This bee is marked by an unusually large quantity
of long gray or white hairs, especially on the abdomen.
Jay A. Smith is using the Watson method in an endeavor to breed a
more yellow and gentler bee. In a private communication he reports
success in diluting the sperm with a saline solution before taking it
into the microsyrmge.
About 25 years before the present methods for the artificial insem-
ination of queen bees were developed, Root (26) greatly stimulated
interest in bee breeding through publicity given a "red clover queen"
of the Italian race, from which was bred progeny said to have excep-
tionally long tongues for Italian bees. This strain soon disappeared.
Among present-day workers in this country who are endeavoring to
Figure 7. — A, Front, wing of honeybee, showing: a-b,
Proximal length measured; b-d, distal length measured;
c, third cubital cell. B, Cubital cell enlarged to show
method of measuring cubital index (a/6). (Drawing by
Snodgrass.)
1408
YEARBOOK, 193 7
breed bees by natural insemination may be mentioned Ralph Benton
and Erwin Alfonsus, the latter formerly with the University of
Wisconsin.
Balinkin (8) and Clifford Muth have pioneered in this country in
the application of ultraviolet rays to young gueens, but details of their
method have not yet been published. An increase in egg laying and
progeny with better dispositions were
reported, but it was not claimed that
this modified behavior is transmissible.
BEE BREEDING IN FOREIGN
COUNTRIES
Numerous foreign workers are inter-
ested in bee breeding (see the appen-
dix) . The work of the German-speaking
beekeepers' association in Switzerland
has already been mentioned. Breed-
ing along the same lines is in progress
in Germany and elsewhere in central
Europe. Zander (40, p. 193), assisted
by A. Himmer, for years used isolated
mating stations to breed an improved
strain of the European brown bee, as
part of the program of the bee-research
institute at Erlangen. Armbruster (2)
is another German investigator who has
worked in this field.
Gotze (7), also of Germany, has been engaged in a biometric study
of progeny of crosses obtained at mating stations. He has reported
unsatisfactory results in the use of artificial insemination. He places
considerable reliance upon certain indices, which are based on pro-
portions involving certain wing cells, as a means of identifying various
strains with which he works. The
most important of these is the cu-
bital index, which is the ratio of the
two parts into which the line joining
the two corners of the third cubital
cell of the front wing on the side
bounded by the cubital vein is di-
vided when a perpendicular is
dropped from this line to the
second recurrent vein (fig. 7, B, il-
lustrates this measurement).
Alpatov (1, p. 24), of the Union
of Soviet Socialist Republics, has
perhaps made a wider use of bio-
metrical indices in studying the differences of races or strains than has
any other investigator. Some indices used by him are the proportion
between width of the first wax gland and width of the sternum that
contains it, length of the hind metatarsus and width of third abdo-
minal tergum, length of hind tibia and width of third abdominal
tergum, length of hind femur and width of third abdominal tergum,
Figure 8.- — Hind leg of worker bee,
showing measurements made: a,
Length of femur; 6, length of tibia;
c, length of metatarsus; d, width
of metatarsus. (Drawing by
Snodgrass.)
liSiP
i
Figure 9-. — Lateral view of worker abdo-
men showing the six abdominal seg-
ments, including a portion of the thorax
at left: a, Left end of third abdominal
sternum; 6, left end of third abdominal
tergum. (Drawing by Snodgrass.)
BEES 1409
distal length and proximal length of front wing, and width and proximal
length of front wing (figs. 7, 8, and 9).
Jaroslav Rytif, of Czechoslovakia, has made observations on the
inheritance of measurable characters of various strains, including
"strain 47". This strain was developed, or rather perpetuated, by the
Austrian queen breeder Sklenar (SI, p. 5) from a colony that had been
outstanding in his apiary. Sklenar thinks the strain is descended from
a mixture of the Carniolan and Italian races, although the workers
show no yellow color. They are usually gray but occasionally one is
reddish brown. Rytif (27) has also studied inheritance of amount of
coloration on abdominal segments, and has devised a workable system
for obtaining quantitative data on this characteristic.
A few years ago Mikhailoff, of the Union of Soviet Socialist Re-
publics, reported considerable success with the Watson method.
From the same country also came the Malyschev method (15). This
differs from the Quinn-Laidlaw method in that the drone organ is
first dissected out under the microscope and then placed in position
in the queen. Prell (25), of Germany, working independently,
reported success with a method like that of Malyschev.
GEOGRAPHICAL STATUS OF DEVELOPMENT
OF BREEDING TECHNIQUE
In the United States successful methods for the controlled mating of
queen and drone under laboratory conditions have been developed
and existing races of the honeybee have been tried out. In western
and central Europe workers have made praiseworthy attempts at the
improvement of bees by selective breeding in isolated mating stations.
In the Union of Soviet Socialist Republics breeding work has centered
largely around biometric studies in an endeavor to reduce the char-
acteristics of races and strains to some sort of mathematical formula
whereby each can be more easily distinguished. Some work has been
carried out with artificial insemination.
CYTOLOGICAL STUDIES 2
Too little is known concerning the cytology of the honeybee. For
a long time the work of Nachtsheim (20), which seemed to show that
the diploid number of chromosomes (that of queen and worker) is
32 and that the haploid mimber (that of drones) is 16, has been ac-
cepted as standard. In recent work, however, Sanderson (29) has
questioned whether Nachtsheim has reported the normal numbers or
whether they are not 16 and 8 for queen and drone, respectively.
The characteristic shape of any of the chromosomes has not yet been
determined.
Even the type of sex chromosome and the method of sex determina-
tion in the honeybee are still undetermined. Nachtsheim holds that
the sex chromosomes are of the X type, the female possessing two and
the male but one, since the drone arises from an unfertilized egg.
Likewise the female possesses twice as many other chromosomes
(autosomes) as does the male. Consequently, according to Nacht-
sheim, sex is determined on a quantitative basis — doubling the sex
' The following sections are written primarily for studonts and others professionally interested in breeding
or genetics, although some of the results discussed are also of general interest.
1410 YEARBOOK, 1937
chromosome and autosome complement results in a female instead
of a male. This view is not in accord with the theory of genie balance
that is now applied to so many organisms. According to this theory,
sex is not determined on a quantitative basis, but is the resultant of
a tendency towards maleness or femaleness in genes of the autosomes
taken as a group and an opposing tendency in genes of the sex chromo-
somes.
In contrast to Nachtsheim's theory of sex chromosomes in the
honeybee, Whiting (39) holds that in the parasitic wasp Habrobracon
juglandi,s Ashmead, another hymenopterous form in which males
develop parthenogcnetically, the two sex chromosomes of the female
are of the XY and not of the XX type. Consequently two types
of haploid males develop, depending on whether they contain a
single X or a single Y chromosome. Outwardly they appear alike,
but they can be identified genetically. They are produced in equal
numbers. Of even greater interest, two types of biparental males
are to be found and these contain either two X or two Y chromo-
somes. Biparental males, like the females, carry two sets of
autosomes, but cannot be distinguished from the ordinary par-
thenogenotic males unless the parent male possesses a factor that
is dominant to the homologous factor carried by the homozygous
mother.
Whiting (39), basing his conclusions on experimental evidence,
explains sex determination in Habrobracon by assuming that the X
chromosome carries the factors F.g while the allelomorphs (f.G) of
these two factors are carried by the F chromosome. The presence
of both F and G, classed as "complementary factors" by Whiting, is
necessary for the development of a female, otherwise only a male will
result. The dominants F and G would both be present, of course,
whenever fertilization of the egg represents the union of A' and Y,
since the egg would then carry the factors F.gjf.G. The union of a
sperm and an egg each of which has an X chromosome, or each of
which has a Y chromosome, could only result in a biparental male,
because in either event the fertilized egg would contain only one of
the two dominant complementary factors necessary if a female is to
result. The factors in the one case would be F.g/F.g, and, in the
other j.G\j.G, Whiting's line of reasoning would hold, whether F
and G each represents only a single dominant gene or whether they
are the symbols of a group of dominant genes carried in their respective
chromosomes (X and Y).
Whiting (38) first encountered biparental Habrobracon males in a
culture headed by a female homozygous for orange-colored eyes but
mated to a male with black eyes, the dominant color. Instead of all
the sons having orange eyes, a few resembled the daughters in having
black eyes. Such males usually proved sterile, although in certain
instances in which they were mated with females homozygous for
orange-colored eyes a few daughters were obtained, some with orange
eyes and some with black eyes. A knowledge of whether or not
Whiting's results on Habrobracon hold good for the honeybee awaits
further work.
The fact that the drone is haploid seems to have led to the impression
that drones from a heterozygous queen will be only of two kinds,
BEES 1411
corresponding to the queen's maternal and paternal inheritance.
Such a conclusion holds only if one pair of unit factors or linkage
groups is under consideration. For example, normally half the drones
from a queen heterozygous for color — say, yellow and black — would
carry the factor for yellow and half of them the factor for black if
these Were unit factors. Her drones would fall into four types,
however, if their inheritance of any two pairs of unlinked factors is
considered. Thus, if it is assumed that the characters for tongue
length and those for color are not linked, but that each is determined
merely by a unit factor, a queen heterozygous for these two factors
would produce long-tongued yellow drones, short-tongued yellow
drones, long-tongued black drones, and short-tongued black drones.
The greater the number of pairs of unlinked factors that are under
consideration, the greater will be the number of types into which the
drones can be classified.
RESULTS OBTAINED FROM BEE BREEDING
It is unfortunate that Mendel's detailed records have never been
brought to light. His studies were not confined to one race of the
honeybee, since it is reported (9) that he worked on the heather or
Dutch bee, the Italian, the Camiolan, the Egyptian, and the Cyprian,
in addition to the native bee of his region.
Since so much of the work concerned the development of a tech-
nique for breeding the honeybee under controlled conditions, and a
biometric study to determine measurable physical characters of
individual members of a colony as well as characteristic colony
behavior marking races or strains, strictly genetic results are scanty
as yet, and often of a somewhat general nature.
The work of the Department has verified the fact that honeybees
can be successfully carried from generation to generation by means
of artificial insemination, seven successive generations having been
obtained in three seasons' work. Allowing the queen 16 days to
develop from egg to adult, 7 days in which to mate, and 3 more in
which to begin egg laying, there should theoretically be a laying
queen of each successive generation every 26 days, but the normal
hazards and delays of beekeeping have greatly increased this period
in actual practice.
The Department has verified Watson's feat (87) of transferring
sperm from the spermatheca of one queen to that of another. The
queen from which sperm was transferred had been dead for several
hours. This procedure makes possible a type of line breeding, involv-
ing crosses of a drone with his offspring, although on an extremely
limited scale, because the supply of sperm from the original drone
cannot be replenished but will be diminished when transferred from
queen to queen.
The work of the Department also indicates that color and tongue
length can be inherited independently of each other and that each
race has its own size characteristics, which are inheritable and more
or less constant within fairly definite limits. Judging from prelimi-
nary data, some correlation exists between tongue length and mimbcr
of wing hooks, and also between tongue length and length of scapus.
Gotze's statement (7, p. 227) of the correlation between tongue
1412 YEARBOOK, 1937
length and length of labial palpi also seems borne out by the work
thus far.
A hitherto undescribed mutation, involving a yellow coloration on
the face of the bee — principally on the clypeus, geuae, labrum, and,
at times, bases of antennae (fig. 6, .4) — was found in an Italian strain
in the Department's apiary formerly at Somerset, Md., and an attempt-
is being made to obtain a homozygous strain. However, it appears
to be a recessive character.
The development of stock especially resistant to European foul-
brood was announced as the result of selective breeding experiments in
New Jersey (6). In describing the first season's work of the Iowa
Agricultural Experiment Station to find stock resistant to American
foulbrood, Park (24) concluded that variation in resistance to Ameri-
can foulbrood exists. Some evidence of the inheritance of number
of egg tubules has been reported in a private communication from
J. E. Eckert, describing work at the University of California.
Since the World War an independent breeder, Henry Brown of
New Jersey, has developed a light-colored strain, reputed to be very
gentle, by crossing the Cyprian and Italian races, according to a
private communication.
Even years before Brown's work the "golden" Italian bee, a strain
with the anterior portion of each of the first five abdominal tergites
marked with a golden band, instead of only each of the first three as
in the ordinary Italian, was developed in this country, supposedly
by crossing the Italian with the Cyprian. This golden Italian, while
held to be gentle and a beautiful bee, had little repute as a honey
gatherer. Sladen (82) developed a "British golden" by crossing the
English strain of the common black bee, the Italian, and the "American
golden." By continued selective breeding in an isolated locality, a
bee was obtained which Sladen claimed combined the hardiness and
industriousness of the black with the prolificness of the Italian,
although its area of golden coloration was not so extensive as that of
the "American golden." No attempt was made to increase the area
of golden coloration, however, since this character was used merely
to provide breeding stock with drones of such a color that their progeny
could easily be distinguished from that of the common black drone,
which prevailed elsewhere in the locality.
Jay A. Smith reports in a private communication that in crosses
obtained by the Watson method no correlation seemed to exist
between color and gentleness.
The reports of the work in Switzerland are of especial interest to
beekeepers, since rather extensive records are kept showing the
returns from improved (veredelte) stock, meaning that developed at
the mating stations, as compared with those from ordinary or unim-
proved stock. Thus from 1915 to 1928, according to a survey of
certain apiaries which contained colonies of both types of stock, the
honey crop of the improved stock averaged larger per colony each
year than that of the unimproved stock, ranging from 20 percent more
in 1923 to 100 percent more in 1924 (IS, p. SO).
Mikhailoff (18) used the Watson method of insemination to dem-
onstrate that the spermatozoa from white-eyed drones are active,
BEES 1413
and he succeeded in obtaining white-eyed workers and queens.
White-eyed drones apparently do not see and do not mate in nature.
That the gene for white eyes is recessive to the normal eye color
is shown by the fact that with natural mating a queen laying eggs
from which white-eyed drones arise gives only workers with normal
eye color.
In the Department apiary formerly at Somerset, Md., half of the
drones from an Italian queen that produced white-eyed drones were
white-eyed and half were black-eyed, a proportion also observed by
other investigators. A few of the white-eyed drones were seen to
fly off into the air, but none was seen to reenter the hive. Some, on
leaving the hives, made short hops or flew in small circles away from
the hive entrance. In the fall only black-eyed drones were found in
the hive with this queen. Whether at this season the workers
removed the white-eyed drones before emergence is problematical,
since no white-eyed drone pupae were found in any of the sealed cells.
A number of virgins were reared from this queen, but attempts to
inseminate them with sperm from the white-eyed drones were unsuc-
cessful. One of these virgins inseminated with sperm from a normal
drone, however, produced some white-eyed drones. Part of the
worker progeny of the original queen were a lighter yellow on their
abdomens than the ordinary Italian bee.
As for the inheritance of quantitative characters, Mikhailoff re-
ported (17) that a Caucasian queen from a colony with a tongue
length of 6.9393 mm was mated with a central-Russian black bee with
a tongue length of 6.1729 mm, and the resulting cross gave a bee with
tongue length of 6.705 mm. Twelve percent of these hybrids had
tongue lengths of 7.0282 mm, this being greater than that of either
parent race. Two Caucasian queens that were inbred with "brother"
drones had progeny with shorter tongues than those of their worker
sisters. Other quantitative data are included and, although they
represent a very scanty number of colonies, they are of interest
because they are the first statistical data to be published that are
derived from controlled crossing of the honeybee.
Alpatov (1) has concludedas a result of his studies in the Union
oi Soviet Socialist Republics that, in the area covered, absolute size
of body and of wings, relative size of the wax gland, and the color
of the abdomen seem linked. The same is true concerning length of
tongue and length of hind legs. He (1, p. 40) has pointed out that
the constancy of color of the yellow and the black races in the
United States shows that color is an inherited racial characteristic.
Watson (37) has stated that the albino bee is dominant over the
common black bee.
Newell (21) crossed yellow Italians and black Carniolans and found
yellow dominant. Watson (87) crossed a black virgin and a yellow
drone and obtained all black offspring. It may be assumed that
Watson used the common black or Dutch bee. Sladen (S3, p. 64),
in crossing a golden queen with pure black drones, obtained "inter-
mediate" workers that had black bands on the posterior margins of
the second to fifth abdominal tergites, increasing in width from
tergite to tergite toward the rear. The sixth tergite was black. As
a matter of fact, the last abdominal tergite is black in all varieties of
1414 YEARBOOK, 1937
the European honeybee, no mutation showing a different color having
yet been reported.
In work at the Department (22) a daughter of a European brown
bee crossed with a yeltow drone produced workers that might have
been taken casualty as a dark strain of three-banded Italians, possibly
because of the blackness of the posterior bands of each of the first
three abdominal tergites. Practically the same results were obtained
later with Caucasians and Italians.
Mikhailoff (17), in crossing queens of the central-Russian black
bee with golden Italian drones, found yellow to be the dominant color
in 90 percent of the progeny.
Gotze (8) holds that the yellow scutellum, such as occurs in the
Cyprian and other eastern races, is the expression of a dominant unit
factor. He found that a golden queen mated to a black drone gave
workers with yellow scutella. These workers, however, as regards
abdominal coloration, were not golden, but had abdominal segments
with decided black edges, as in the work by Sladen and the writer.
Gotze (8, p. 71) therefore calls the Ft an "intermediate form" and fur-
ther assumes that a separate gene is responsible for the black edges
on the abdominal segments.
Gotze has found in various colonies both black and brown drones
as well as some termed by him "leather-colored." To account for
these various colorations he assumes a basic color factor, N, which
requires the presence of an activating factor to give rise to color. He
assumes that not one but two activating factors or their allelomorphs
are carried. These are M, a factor for black, and B, a factor for brown.
B is inhibited by M. When only their allelomorphs bm are present,
leather-colored individuals arise. Gotze states that m is a factor
for leather-colored but does not give the nature of b. A black drone,
according to this scheme, would have the genie composition NBM or
NbM; a brown drone, NBm; and a leather-colored drone, Nbm. In
addition, Gotze found that certain eggs did not hatch, and he holds
that they had the genie combination nbm, which he assumes is lethal.
In an actual count, omitting the supposed lethal cases, he found 110
black, 48 brown, and 21 leather-colored workers.
Stucki (35) has suggested the possibility that certain definite
excesses or deficiencies from the normal wing venation may be char-
acteristic of certain strains of Swiss bees, although he postpones
definite conclusions until more material is accumulated. Like Casteel
and Phillips (5) and others, he found drones especially variable.
Rytif (28) reports, as a result of crossing the Iskra strain of bees from
Czechoslovakia with the Nigra strain of the European brown bee —
the latter strain having a lower cubital index (fig. 7, B) — that the
lower index is completely dominant over the higher.
The dominance or recessiveness of certain characters of the honeybee
that have been reported as heritable is shown below. It is to be
remembered that most of the data need further confirmation before
being accepted and that, while many of the characters listed seemingly
have little or no direct economic importance in themselves, yet, if
they happen to be linked with characters of economic importance,
perhaps they may ultimately prove of use as an index to the presence
of such characters.
BEES 1415
Dominance or recessiveness as shown in Fi generation
Dominant factors Recessive factors Reported by-
Eye color normal Eye color white Mikhailoff (18) .
Abdominal marking: Abdominal marking:
Italian European brown Mikhailoff (17).
Do Carniolan Newell (21).
Common black Italian Watson (87, p.
40).
Albino Common black Do.
Cubital index low Cubital index high Rytif (27).
Scutellum yellow Scutellum black Munro (19) .
Clypeus, genae, and labrum dark. Clypeus, genae, and labrum Nolan (this arti-
yellow. cle, p. 1534).
Use of wax for sealing crevices, Use of propolis for sealing Newell (81).
etc. (Carniolan). crevices, etc.
Some crosses in which dominance or recessiveness is not shown for certain
characters by Fi generation
Cross Character Reported by-
European brown X Golden Abdominal coloration Gotze (8, p. 71).
Common black X Golden do Sladen (88, p.
64).
European brown X Italian do Nolan (22).
Long X short Tongue length Gotze (8, p. 73).
Some linked characters
Characters Reported by-
Absolute size of body and wings, relative size of
wax glands, color of abdomen Alpatov (1, p. 48).
Tongue length, labial palpi Gotze (8, p. 227) .
Tongue length, number of egg tubules Komarov and Alpatov (11).
Yellow color, light weight (drones) Munro (19).
Black color, heavy wreight (drones) Do.
Now that a notable advance in the technique of accomplishing
matings has been made, methods for obtaining biometric data have
been worked out, and germ plasm that possesses a number of desirable
characters is available, the way appears open for a worth-while
advance in bee breeding, although quick results should not be expected.
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(1) Alpatov, W. W.
1929. BIOMETRICAL STUDIES ON VARIATION AND RACES OF THE HONEY BEE
(apis mellifera l.). Quart. Eev. Biol. 4: 1-58, illus.
(2) Armbruster, L.
1919. BIENENZUCHTUNGSKUNDE. VERSUCH DER ANWENDUNG -WI6SEN-
SCHAFTLICHER VERERBUNGSLEHREN AUF DIE ZUCHTUNG EINES
ntttztieres. 120 pp., illus. Leipzig, Berlin.
(3) Balinkin, I.
1930. the wonders within the bpectrtjm. Beekeepers' Item 14:
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(4) Bishop, G. H.
1920. fertilization in the honey-bee. i. the male sexual organs:
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1903. COMPARATIVE VARIABILITY OF DRONES AND WORKERS OF THE
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(6) FlLMER, R. S.
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1416 YEARBOOK, 193 7
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(8)
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1930. die rassenzucht der schweizer imker. Aufl. 7, revised by
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(14) Laidlaw, H. J., Jr.
1932. hand mating of queenbees. Amer. Bee Jour. 72: 280.
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1924. [artificial insemination of the honeybee.) Chelovek i Priroda
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(18)
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(19) Munbo, J. A.
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1915. inheritance in the honey bee. Science (n. s.) 41: 218-219.
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1936. DISEASE RESISTANCE AND AMERICAN FOULBHOOD. Amer. Bee Jour.
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(26) Root, E. R.
1900. our $200 red clover queen and her daughter. Gleanings
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BEES 1417
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(28)
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1909. BREEDING THE BRITISH GOLDEN BEE IN RIPPLE COURT APIARY.
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1913. QUEEN-REAKING IN ENGLAND. WITH NOTES ON A SCENT-PRODUC-
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(34)
1920. queen-mating EXPERIMENTS. Gleanings in Bee Cult. 48: 717-718.
(35) Stucki, H.
1936. HAT uns das ADERBILD DES bienenflugels wichtiges zc sagen?
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(36) Watson, L. R.
1927. controlled mating of queenbees. 50 pp., illus. Hamilton, 111.
(37)
1927. controlled mating in the honeybee. Iowa State Apiarist
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(38) Whiting, P. W.
1921. HEREDITY IN WASPS. A STUDY OF HEREDITY IN" A PARTHENOGE-
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(39)
1935. sex determination in BEES and wasps. Jour. Hereditv 26:
263-278.
(40) Zander, E.
1930. die zucht der biene. Ed. 3, 310 pp., illus. Stuttgart.
APPENDIX
Some Workers Identified with Bee Improvement at Stale and Federal Experiment Stations
and Other Institutions
State Agricultural Experiment Stations:
California, Davis: J. E. Eckert.
Connecticut, New Haven: L. C. Curtis.
Iowa, Ames: O. W. Park.
Kansas, Manhattan: E. J. McNay.
New Jersey, New Brunswick: R. *S. Filmer.
Texas, San Antonio: H. B. Parks.
Wisconsin, Madison: H. Laidlaw.
Other institutions:
Brigham Young University, Provo, Utah: J. Fleming Wakefield.
Alfred University, Alfred, N. Y.: L. R. Watson.
Depauw University, Greencastle, Ind.: Jay A. Smith.
United States Department of Agriculture, Bureau of Entomology and Plant
Quarantine:
Baton Rouge, La.: Otto Mackensen.
Beltsville, Md.: W. J. Nolan.
Laramie, Wyo.: A. P. Sturtevant.
138904°— 37 90
1418 YEARBOOK, 1937
Some Workers in Foreign Countries Identified with Bee Improvement
Austria, Mistelbach: Guido Sklenar.
China, Fukien Christian University, Foochow: C. R. Kellogg.
Canada, Dominion Experimental Farms, Ottawa: C. B. Gooderham.
Czechoslovakia, Krpy: Jaroslav Rytif.
Czechoslovakia, Ober-Hohenelbe: Egon RotteT.
Egypt, Matarich, Cairo: A. Z. Abushady.
Germany, Landesanstalt fiir Bienenzucht, Erlangen: E. Zander and A. Himmer.
Germany, Landwirtschaftliche Hochschule, Hohenheim bei Stuttgart: G. A.
Rosch.
Germany, Rheinische Lehr- und Versuchsanstalt fiir Bienenzucht, Mayen-Eifel:
G. Gotze.
Germany, Berlin-Zehlendorf: L. Armbruster.
India, Punjab Agricultural College, Lyallpur: S. Singh.
Italy, Instituto Zoologico della R. University di Bologna: Anita "Vecchi.
Switzerland, Verein Deutsch-Schweizerischer Bienenfreunde, St. Gallen: M.
Justricb.
Union of Soviet Socialist Republics, Ecological Laboratory, Moscow: W. W.
Alpalov.
Union of Soviet Socialist Republics, Petrovka, Moscow: A. S. Michailoff.
FUNDAMENTALS OF
HEREDITY FOR BREEDERS
E. N. BRESSMAN, Scientific
Adviser, Office of the Secretary '
1 HE preliminary articles in the 1936 Yearbook included some dis-
cussion of the fundamental nature of genes and chromosomes, but very
little about how the chromosomes, the carriers of the genes that are
the determiners of hereditary traits, are distributed among the de-
scendants of two parents used as breeding stock. This distribution
occurs in certain genetic ratios, which were first discovered by Johann
Gregor Mendel and gave the clue to the orderly operation of heredity.
Before explaining them, it is necessary to consider what happens when
two reproductive cells unite to produce progeny.
WHAT HAPPENS WHEN THE CELLS UNITE
This has been well described by A. H. E. Buller in his account of
the discovery of Marquis wheat. Buller not only understood the
facts of his science of botany ; he had a feeling for its poetry as well.
The following description is taken from Ids book. Telling how all
Marquis wheat plants came originally from a single kernel or seed,
the offspring of a cross between Red Fife and Hard Red Calcutta
selected by the famous Canadian plant breeder, Charles Saunders,
Buller wrote: 2
Pollen dust from some stamens removed with forceps from a few flowers of
[Red Fife] was placed on the two feathery stigmas of a flower of [Hard Red Cal-
cutta]. The pollen grains germinated, each grain producing a single pollen tube.
The pollen tubes, which were exceedingly delicate cylindrical structures, grew
down the stigmas and made their way, by elongating at their apices, into the
ovary below. This ovary was a tiny chamber containing a single ovule or potential
seedattached laterally to its wall. One of the pollen tubes, guided by chemo-
tropic stimuli, directed its course toward the ovule, entered at its mouth or micro-
pyle, and penetrated into its interior as far as the ovum or egg-cell. The egg-cell
having been reached, the wall at the tip of the pollen tube liquefied and broke
down, and from the opening so produced there were emitted two exeeedingly
minute dense rounded masses of gelatinous protoplasm known as male nuclei.
One of these nuclei, carried by forces as yet not perfectly understood, advanced
through the general protoplasm of the egg-cell toward the female nucleus situated
in its center. The male and female nuclei, after coming into contact, brought
their affinity for one another to a climax by mingling together and forming one
whole; and this nuclear fusion, this formation of a single nucleus from two others
of opposite sex, marked the completion of the act of fertilization. * * * With-
'Many workers in the Department have made contributions to this article. The writer is indebted
particularly to George Haines, senior animal husbandman, Office of Experiment Stations, and W. V. Lam-
bert, senior animal husoandman, Bureau of Animal Industry, who have been very generous^withsuggestions
and help on animal genetics, not only in this article but elsewhere in tho Yearbook.
' R. Buller, A. H. essays on wheat; including ttif. discovery and introduction or marquis wheat,
THE EARLY HISTORY OF1 WHEAT-GROWING IN MANITOBA, WHEAT IN WESTERN CANADA, THE ORIGIN OF RED
ROBS AND KITCHENER, AND THE WILD WHEAT OF PALESTINE. 339 pp., illus. Newi'ork. 1919. See pp.
219-220.
1419
1420 YEARBOOK, 1937
out fertilization, the egg-cell would have * * * withered and died; but, its
fertilization having been accomplished, a most extraordinary future was opened
to it. Further development became irresistible, with the result that, in the course
of a few years, its products became in numbers like the stars on a clear night, or
the grains of yellow sand upon a sea beach.
To round out the description, it is necessary to add that when the
male and female nuclei fuse, the resulting single nucleus becomes the
embryo of a new plant. But this embryo is not the whole seed. It
will be noted that there were two male nuclei, only one of which united
with the female nucleus. But there was also more than one female
nucleus, for this one was attended by two much smaller bodies known
as the polar nuclei. During fertilization, these two polar nuclei
united with the other male nucleus and from this separate union came
the endosperm, the starchy part of the seed, the function of which is
to furnish food for the embryonic plant during the initial stages of
its growth. This union of a male nucleus with two female polar nuclei
is peculiar to plants, and it accounts for the fact that the male parent
may immediately impress certain characters on the endosperm and
embryo of the seed — a phenomenon known as xenia. Except for
xenia and metaxenia, the inheritance from the male parent does not
appear until the new plant has grown and produced seed in its turn.
This immediate effect of the two polar nuclei, visible in the endo-
sperm, is commonly seen in corn. When a pollen grain from purple
corn pure for this characteristic fertilizes an egg cell of white corn,
for example, the resulting seed is purple. In some other seeds, like
wheat, the effect of xenia is not evident because the endosperm is
covered with female tissue known as the pericarp ; but even though it
is not always observed, xenia occurs hi all seed plants. It might be
added here that certain other tissues associated with the seed may
sometimes be affected in a similar manner by the male parent. This
happens in the case of date fruits, and the phenomenon, which has
been called metaxenia, is discussed in the date section of the article on
subtropical fruits.
The details of the process of fertilization in animals differs somewhat
from that in plants although the end result in each case is a new
individual which received half of its heredity from the male parent
and half from the female parent. In animals the male reproductive
cells, known as spermatozoa, are produced literally by the millions in
the testes or sex glands of the male. They are microscopic, motile
cells, which are propelled by long hairlike tails. The larger part of
the head of the spermatozoon is composed of the nucleus, the part of
the cell that carries the hereditary factors. The female reproductive
cells, known as ova, are produced in the ovaries or sex glands of the
female. They are much larger than the male reproductive cells and
are nonmotile.3 They contain a microscopic nucleus that corresponds
in size to the nucleus of the spermatozoon. The remainder of the egg
consists largely of food material intended to nourish the young embryo
until food connections are established with the tissues of the mother,
or in the case of birds and other forms in which development takes
3 The yolk of the hen's egg is the true egg; the remainder of the contents within the shell are secreted by
the glands of the oviduct or "egg hag." Most of the yolk consists of food material. The eggs of mammals
are much smaller than the eggs of birds. Most mammalian eggs are of a size that makes them barely visible
to the naked eye.
FUNDAMENTALS OF HEREDITY 1421
place outside of the body of the female, food to nourish the embryo
throughout its entire development.
In contrast with plants, the spermatozoon, which corresponds to a
pollen grain, and the egg cell, which corresponds to the ovule of the
plant, are ready to function in fertilization without further nuclear divi-
sions. The sperm cells are deposited by the millions in the reproductive
tract of the female at the time of mating. From the point of deposit
they move in a swarm to the innermost part of the reproductive tract
(the fallopian tubes) of the female, where they are ready to unite with
the egg or eggs as soon as they are freed from the ovary. Normally
only one spermatozoon enters the egg and takes part in fertilization
although thousands of spermatozoa surround an egg. When the sper-
matozoon enters the egg its nucleus unites with the nucleus of the egg,
and this joining of the two nuclei into a single new nucleus is what is
known as fertilization. The new nucleus, which received half of its
heredity (genes) from the male parent and half from the female parent,
constitutes a new individual. All animals and plants begin their life as
such single cells. From that point growth proceeds by a continual
process of cell division and as it proceeds the new cells are formed into
the tissues and organs of the body of the new animal. The processes
of growth are similar in both plants and animals. The embryo observed
in the seed of plants is a partially developed plant since it contains
many cells that arose by the division of the fertilized ovule.
Now we must consider another aspect of those male and female
nuclei whose union was described by Buller for wheat plants.
It is generally recognized that the chromosome number for a given
species is constant. For example, every nucleus in each body cell of
the Red Fife and Hard Red Calcutta parents contained 21 pairs of
chromosomes, or 42 altogether. But the nucleus of each reproduc-
tive cell — as distinguished from the body cell — contained only 21
chromosomes, not 21 pairs. (This reduction in number occurs when
reproductive cells are formed, as described by Kempton.)4 These 21
chromosomes in the male Red Fife reproductive nucleus contained a
complete set of genes capable of reproducing all the Red Fife charac-
teristics; and the same thing was true for the female Hard Red Cal-
cutta nucleus. The two joined, promptly lost their individual
identity, and formed a new nucleus with 42 chromosomes containing
all the genes of both parents, and therefore capable of producing their
characteristics. From that cell came a new plant, the first-generation
or Fx hybrid5 between the two.
Under ordinary circumstances, if the two parents are pure, all the
Fx or first-generation plants of the cross are exactly alike, for each
individual offspring contains a full set of genes from the mother and
a full set from the father and it expresses the dominant characteristics
of both of them. Very often also these Fi hybrid plants are unusually
vigorous in size or productiveness or other characteristics, especially
if the parents were considerably unlike one another. This is the well
known "hybrid vigor" or heterosis, for which several explanations
have been suggested.
4 Kempton, J. H. Heredity under the microscope. U. S. Dept. Agr. Yearbook 1930: 165-182, 111ns.
1936.
• l'i is pronounced eff-one. The F stands for filium or filial, depending upon whether it is used as a noun
or an adjective, and the subscript numerals indicate which generation is meant — first, second, third, etc.
1422 YEARBOOK, 1937
One of these explanations is that all the dominant genes from both
parents have a chance to express themslves in the hybrids. To take
an imaginary example, suppose one parent had a dominant gene for
height so that it was tall, but it had small leaves because of a reces-
sive gene. Suppose the other parent had large leaves because of a
dominant gene, but that a recessive gene for dwarfness made it a
short plant. The Fi hybrid would then be tall because of the dominant
gene for height inherited from one parent, and it would have large
leaves because of the dominant gene for leaf size inherited from the
other parent. A number of such dominant genes might express
themselves and in combination make the Fi hybrid seem unusually
vigorous. Or, to consider another characteristic such as disease
resistance — each parent might have certain dominant genes that
increase resistance. When all of these genes came together in the
progeny, it might be more disease-resistant than either of the parents.
Another suggested explanation of hybrid vigor is that it is the
result of physiological stimulation, which somehow comes from the
mixing of unlike protoplasm from the egg and the sperm.
SEGREGATION OF CHARACTERISTICS IN THE PROGENY
But hybrid vigor is not the immediate point of this discussion. We
are not concerned here with what happens in the first hybrid genera-
tion, but with what occurs in the second generation, which breeders
call the F2. This is well illustrated in figure 1.
We shall assume that both the original parents have been bred
pure, and that the Fi generation is then inbred or fertilized by its own
pollen to produce the F2 generation — the grandchildren of the original
parents. What happens to the chromosomes in the F2 progeny?
Perhaps this can best be visualized for the present by concentrating
on a single pair of genes, let us say a pair governing height. Now
genes have alternative forms, called allelomorphs or alleles (allelomorph
comes from two Greek words meaning "alternative form"). Suppose
that a gene for height in the original male parent was one that made
the plant tall. Suppose that the gene in exactly the same place on the
corresponding or homologous chromosome in the original female
parent was an allel or alternate that made the plant short. The
Fx hybrid would receive both chromosomes, making a pair, with the
gene for tallness in one and the gene for shortness in the other. These
two genes would be present in every body cell of the Fj. But the time
would come when reproductive cells were formed, and this would
involve the separation of the two members of a pair of chromosomes,
since each reproductive cell receives only one chromosome where there
were two in the body cell. Thus whenever an original cell divided to
form two male reproductive cells, one of them would be bound to receive
the chromosome containing the gene for tallness and the other would
be certain to receive the chromosome containing the gene for shortness.
If several thousand male reproductive cells were produced by the plant,
half of them would have the tallness gene, half the shortness gene.
And the same thing would be true of the female reproductive cells.
Next this plant is to be self-fertilized; its own male nuclei are to
join with its own eggs to form the primary cells of F2 plants, the next
generation. Obviously there could be four kinds of these new cells.
FUNDAMENTALS OF HEREDITY
1423
THE SEED PARENT
Cucurbita moschata
var. Japanese Pie
THE POLLEN PARENT
Cucurbita Pepo
var. Mammoth Yellow Bush Scallop
X
FRUIT OF THE Fj
GENERATION
(The seeds in. this
"gramma" have hybrid
embryos formed by
applying pollen from,
the other parent to
the pistil which.
matured into this
fruit)
(Pollen from flowers
on a plant thatr
produces the above
type of fruit carried
half the plant
characteristics which
went to form, the
hybrid embryos)
Seeds of the squash above retain in various combinations
characteristics of both parents shown at the top. The*
pistil that developed into this fruit was fertilised by
pollen from, a staminate flower of the same plant
II
FRUITS OF THE F2 GENERATION.
These fruits show how the characteristics of both parents reunite
in various combinations to produce new types
Figure I. — A cross between two species of cucurbits widely differing in appearance.
Typical fruits of the parental types; the first generation, which exhibits dominant
characteristics: and the second generation, which exhibits characteristics of both
parents in various combinations. This is a typical example of the operation of
Mendelism. (Courtesy of New York (State) Agricultural Experiment Station.)
(1) A male nucleus with a tallness gene might join a female cell with
a tallness gene, giving "tallness-tallness."
(2) A male nucleus with a tallness gene might join a female cell with
a shortness gene, giving "tallness-shortness."
1424 YEARBOOK, 1937
(3) A male nucleus with a shortness gene might join a female cell
with a tallness gene, giving "shortness-tallness."
(4) A male nucleus with a shortness gene might join a female cell
with a shortness gene, giving "shortness-shortness."
Since there are as many reproductive cells that carry the tallness
gene as there are reproductive cells that carry the shortness gene and
fertilization of the two kinds of eggs by the two kinds of pollen grains
occurs entirely by chance, there would be equal numbers of these four
different kinds of new cells if large numbers were produced. But
group (2) and group (3) above would be exactly the same in effect,
since each is a tall-short combination. Thus the proportions in the
total population would be 1 tall-tall to 2 tall-short to 1 short-short.
This is a simple Mendelian characteristic, the probable breeding
behavior of which is expressed as a 1 to 2 to 1 or 1 : 2 : 1 ratio.
Thus the plants in the F2 generation are not at all like those in the
Ft. In the F,, all are alike; in the F2, with exactly the same basic
characteristics, there are three different kinds of plants, with respect to
this pair of genes, and they occur in definite proportions. That is,
they occur in definite proportions if the population is large enough and
is considered as a whole. If only a few plants were produced, these
proportions might not hold; out of any four individuals selected at
random, there would obviously be a very small chance that one would
be a tall-tall, two tall-short, and one short-short. But for large
numbers, the ratios hold well. This might be compared to the fact
that any given family may have more boys than girls, or vice versa,
but that on the whole the male and female population is about equal.
Segregation Ratios
This splitting up into several combinations of characteristics in the
second generation is what is technically called segregation, and the
generation in which it occurs is often called the segregating generation.
Segregation occurs even in pollen grains as is shown in figure 2. It
should be noted that segregation may occur in the F! if the parents are
hybrids rather than bred pure. For example, if the hybrids in this
example were the original parents, segregation would begin in the first
generation after they were selfed or crossed. But this would be merely
a change in names; what was really the F2 would now be called the E\.
It is important to remember, however, that whenever hybrid material
is used to start with — as it often is in practice — segregation is apparent
in the first generation. In fact, this is the test that proves whether
the parent material is hybrid or pure. If a breeder takes a plant the
ancestry of which he does not know, selfs it, and finds the progeny in
the next generation segregating into different types, he knows the
original plant must have been a hybrid. This is what happens, for
example, with ordinary open-pollinated varieties of corn. Upon
being selfed, the progeny begins to segregate into types immediately.
Before going on with the discussion of segregation ratios, it might
be well to consider what happens on further inbreeding of these F2
plants. We derived three kinds — the tall-tall, the tall-short, and the
short-short. When reproductive cells are formed in the tall-tall
plant, obviously every one of them must receive a tallness gene, since
there is no other. Thus when such plants are selfed all the descend-
FUNDAMENTALS OF HEREDITY
1425
ants of the tall-tall plants will also have the tall-tall combination, and
this will go on indefinitely as long as they are selfed. Likewise, the
short-short plants will produce only short progeny. AVhenever an
organism has exactly the same genes for a certain character on botli
members of a pair of homologous chromosomes, it is said to be homozy-
gous for that character Ordinarily, it will go on breeding true for
that character indefinitely
as long as it is selfed. From
a genetic standpoint, this is
what pure breeding means.
Often the effort of the plant
breeder is to produce plants
that, for practical purposes,
are homozygous for all
characters. Then he can
continue reproducing them
indefinitely with the assur-
ance that the progeny will
be like the parents. His
basic procedure — though
there are many necessary
modifications and complica-
tions— is commonly the one
given here.
But what about the third
type mentioned above — the
plants with the tall-short
combination in their cells?
Here we have exactly the
same combination we had
in the Fi. In each cell of
this type there is a chromo-
some containing the gene for tallness and one containing the gene for
shortness. One-half of the reproductive cells, then, would get the
gene for shortness and one-half the gene for tallness. Thus when the
plants with the tall-short combination are inbred, they again segregate
in the next generation into 1 tall-tall, 2 tall-short, 1 short-short.
When an organism has two alternative genes for a certain character
in its homologous chromosomes, it is said to be heterozygous for that
character, as opposed to homozygous.
Effect of Dominance
So far, we have dealt only with what are called the genotypes of this
tall-short combination in breeding. The segregation in the F2 really
took the form of 1 tall-tall, 2 tall-short, 1 short-short so far as the
actual cells of the progeny were concerned. But it happens that with
these particular characters of tallness and shortness there is a compli-
cation, namely, that tallness is a completely dominant characteristic
and shortness a recessive. This means that when a cell contains the
gene for tallness in one chromosome of a pair and the gene for shortness
in the other, the tallness gene will dominate in the growth of the plant,
and the shortness gene will, as it were, recede into the background.
Figure 2. — An early effect of u gene on a charac-
teristic is shown in these pollen grains from a sor-
ghum plant heterozygous for the waxy gene.
One-half of the pollen grains are waxy and stain
red (light) with iodine, while the remainder are
starchy and stain deep blue (dark). (Courtesy of
Journal of Heredity.)
1426 YEARBOOK, 1937
We know that the cell actually contains both genes, but the plant does
not show it so far as appearances go ; it is a tall plant. In breeding
terminology, its phenotype, which literally means its appearance type,
is tall; its genotype, which literally means its breeding type, is tall-
short. The genotype designates the actual genie constitution regard-
less of expression. The phenotype is the type that results from the
interaction of the genes among themselves, as well as with the
environment.
Thus in this case the phenotypic and .genotypic ratios are not the
same. All the plants with the tall-tall combination in their cells will
of course be tall, but so will all the plants with the tall-short combina-
tion, because tallness is dominant. So far as the phenotype is con-
cerned, then, the ratio becomes 3 tall plants: 1 short plant (the one
with the short-short combination). This also is a simple phenotypic
ratio, which is really only a modification of the genotypic 1 :2:1 ratio
and is produced whenever complete dominance is involved. Where
there is no complete dominance, the segregation of the phenotype as
well as of the genotype is 1 : 2 : 1 . This occurs, for example, when the
hybrid pink four o'clock, a flower, is selfed. The progeny segregates
in the ratio of 1 red : 2 pink : 1 white.6 Ked in this case is partly domi-
nant, but not enough to make plants with the red-white combination
red in appearance. They are pink instead.
Another ratio that is a variation of the 1:2:1 was obtained by
Cuenot, crossing yellow and black mice. The dominant gene, desig-
nated Y, produces yellow, and its allel, y, produces black.7 Now it
happens that when a cell received the homozygous combination YY,
it could not live; that is, this gene was lethal for any cell that received
it in both chromosomes of the pair. With only one Y, however, the
cell could live. Thus in the segregation 1 YY:2 Yy.l yy, the YY
perished, leaving a ratio of 2 : 1. Since yellow (Y) was dominant, the
phenotypic ratio was 2 yellow mice (Yy) to 1 black mouse (yy).
There are many lethal genes in animals and plants that would give
the same sort of results, but in most cases the lethals are recessives
rather than dominants.
Such ratios are useful to the breeder in two ways. If he knows that
a certain character is governed by a single pair of genes, he can tell
what proportion of each type he will obtain in a large segregating
progeny. When he does not know how many genes are involved in
a certain character, he can find out, or obtain an estimate, at least, by
figuring the ratio in the segregating progeny. If the character segre-
gation is 1 :2:1, he concludes he must be dealing with a single pair of
genes and that complete dominance is not involved. If it is 3:1, he
assumes it is a single pair of genes involving complete dominance. If
it is 2 : 1, he knows it may be a single pair of genes, and that one of the
alleles in the double condition is lethal.
6 Knowledge of the 3:1 phenotypic segregation preceded that of the 1:2:1 as a phenotypic ratio. One of
the first reports of the latter was made by Corrcns— German botanist and one of the rediscoverers of Men-
del's original paper— working with the hybrid pink four o'elocks mentioned. There is no gene for pink,
but the color is produced by the interaction of thewhiteness and the redness genes in the same cell. The
same result is obtained in the blue Andalusian fowl, which is produced by crossing a splashed white with a
black. The segregation in the F2 is 1 splashed white:2 blue:l black. This ratio also occurs in commercial
double carnations, produced by crossing the burster and the single varieties.
' The genetic formula is somewhat simplified. Tho designation is in accordance with the practice of desig-
nating a recessive gene by a lower-case letter and its dominant allel by the same letter capitalized.
FUNDAMENTALS OF HEREDITY
1427
*» z
Ratios With More Than One Pair of Genes
The situation becomes much more complicated when there are two
pahs of genes and their alleles to be taken into account instead of one
pair. Corn has been a favorite plant for studies of this kind. Figure
3 shows same heritable characters in corn.
Consider a pea plant with a pair of genes for tallness (T — dominant)
and a pair of genes
for red blossoms (R —
dominant) crossed
with a plant that has
alleles (t and r) of
these two genes and
is dwarf (recessive)
and white-flowered
(recessive). The gen-
otypic segregation, in-
cluding all possible
combinations of these
two characteristics,
would be like this:
Parents: Tall -tall
red-red X8 dwarf-
dwarf white -white.
The first parent indi-
cated here would pro-
duce only gametes
(germ cells) carrying
genes for tall and red,
while the second par-
ent would produce
only gametes carrying
genes for dwarf and
white. The progeny,
Fi, of course, would
carry both kinds of
genes, that is, geno-
typically they would
be tall-dwarf red-
white; but in pheno-
typic appearance they
would all be tall and
red.
Ft: tall-dwarf red-
white X tall-dwarf
red-white. The gam-
etes produced by each
of the parents here
would be of four
kinds — tall-red, tall-
white, dwarf-red, and
-«
* The symbol
"crossed with."
X stands (or
Figure 3. — Segregation for more than one character is
shown on these ears of corn. It will he noted that
there is not only a variation in color of the kernels but
also a difference in the development of the kernels.
Studies of heritable characters of this kind have enabled
geneticists to increase their knowledge of heredity greatly
beyond the fundamental laws formulated by Mendel.
(Courtesy of Journal of Heredity.)
1428
YEARBOOK, 1937
dwarf-white. These four kinds of gametes would unite by chance to
give the various F2 progeny. Possibly the best way to show the for-
mation of these F2 genotypes is by what is commonly known as the
checkerboard square, presented below. The gametes produced by
each parent are shown at the top and side of the checkerboard square.
The genotype of each of the progeny formed by the union of all
the different kinds of gametes is shown within the squares.
F2:
Parent (gametes)
to
TR
TTRR
Tr
tR
tr
TR
TTRr
TtRR
TtRr
Tr
TTRr
TTrr
TtRr
Ttrr
tR
TtRR
TtRr
URR
URr
ir
TtRr
Ttrr
URr
ttrr
Progeny (zygotes)
This F2 checkerboard square adds up to the following genotypes:
1 tall-tall red-red: 2 tall-tall red-white: 2 tall-dwarf red-red: 4 tall-dwarf
red-white: 1 tall-tall white-white: 2 tall-dwarf white-white: 1 dwarf-
dwarf red-red: 2 dwarf-dwarf red-white: 1 dwarf-dwarf white-white.
But tall is dominant to dwarf and red is dominant to white; that
is, every plant with the tall-dwarf combination in its cells would be
tall in appearance, and every plant with the red-white combination
would have red flowers. Thus in the F2, the segregation from the
standpoint of phenotype or appearance would be:
Tall red —9 (1 tall-tall red-red +2 tall-tall red-white+2 tall-dwarf red-
red +4 tall-dwarf red- white).
Tall white — 3 (1 tall-tall white-white +2 tall-dwarf white-white).
Dwarf red — 3 (1 dwarf-dwarf red-red +2 dwarf-dwarf red-white).
Dwarf white — 1 (dwarf-dwarf white- white).
This 9:3:3:1 is the basic phenotypic ratio when two independently
inherited dominant genes with their two recessive alleles are concerned .
Modifications of Basic Ratios
The basic ratios are modified in various ways. Interaction between
the genes accounts for many of the modifications. It will be enough
here to analyze five of the most common of these modifications through
interaction.
(1) One dominant gene may have no visible effect unless a member
of another pair is present. There is an example of this in corn, in
which many color genes have been identified by E. A. Emerson and
Ins associates at Cornell University. The dominant gene B governs
red color, and its recessive allel r produces white. The dominant gene
Pr produces purple, but only if R is present; otherwise it has no
FUNDAMENTALS OF HEREDITY 1429
effect. Suppose we have corn with the genes r and Pr (expressed as
r Pr). This is white because, though it contains the gene for purple,
Pr, it does not at the same time possess R. Let us cross this with a
variety containing the genes R pr, which is red because it contains the
R without the Pr that would modify it. Since the Fi would have all
the genes from both parents, its constitution would be R r Pr pr.
It would be purple because it would have both R and Pr. The geno-
types would work out in the 9:3:3:1 ratio already given — that is:
9 R-Pr-3 (purple, because R and Pr are both present) .
3 R-prpr (red, because R is present but not Pr) .
3 rrPr- (white, because though Pr is present, it lias no effect without R).
1 rrprpr (white — double recessive).
Thus the phenotypes add up to 9 purple: 3 red: 4 white, and we get
9:3:4 as the typical ratio for this kind of gene interaction.10
(2) Sometimes two dominants have a complementary effect on
one another, but neither exerts any visible influence alone. Again
we may turn to corn for an example. The dominant gene C and the
dominant gene R produce colored (red or purple) kernels if they are
both present, but neither has any effect alone. The recessive alleles,
c and r, produce white. Suppose we have a variety with the com-
position CCrr, which is white because only one of the dominant genes
is present, and another variety ccRR, white for the same reason.
The Fj contains the two dominants and the two recessives — Gc Rr —
and is therefore colored. All the possible combinations would give
us the following genotypes in the F2:
9 C-R- (colored, because both dominants are present) .
3 C-rr (white, because only one of the dominants is present).
3 ccR- (white, because only one of the dominants is present) .
1 ccrr (white — double recessive) .
Here the phenotypes add up to 9 colored: 7 white, and one concludes
that 9:7 is the typical ratio for this kind of interaction.11
(3) Sometimes one dominant hides the effect of the other when
both are present. In oats, the gene G produces a gray seed coat and
the gene B a black seed coat, but the effect of 6 is always hidden
if B is present. The gene Y produces a yellow seed coat, but only if
neither B nor 6 is present. Suppose we cross a variety BBGGYY
(black because B hides G and Y) with a variety bbggYY (yellow
because Y is present but not B or G). The Fr is BbGgYY and is
therefore black. All possible combinations would give in the F2:
9 B-G-Y- (black because B hides G and Y).
3 B-ggY- (black because B hides Y).
3 bbG-Y- (gray because G can show its effect without B).
1 bbggY- (yellow because Fis present without B or G).
This gives a phenotype ratio of 12 black, 3 gray, and 1 yellow — 12 :3 : 1
being the typical segregation for genes interacting in this way.
(4) Sometimes when there are two dominants, one acts as an
inhibitor of the other. For example, in corn, R produces red kernels;
3 The small dash (.-) In the symbol stands for the presence of either the dominant or the recessive gene.
In this case, R- stands for RR or Rr, while Pr- stands for Pr Pr or Pr pr.
10 In this particular example, there are really four other known genes present, At, At, C, and i. Together,
these genes produce color when R is present, but they have no effect when R is not present. The real com-
position of the white parent, then, is AiAiAsAiCCrrPrPrii; of the red parent AiAiAiAiCCRRprprii;
and of the purple Fi, AiAiAzAiCCRRPrPrii. Since AiAiCi is the same in all three cases, it is omitted to
make the analysis clearer.
" This example is also somewhat simplified in the genetic formula.
1430 YEARBOOK, 1937
r white kernels ; / prevents the action of B ; i has no effect. Stated in
another way, the recessive (n) must be present to allow the gene R
to be effective. Suppose a variety rrii (white, the double recessive)
is crossed with RRII (also white because, though R is present, it
is inhibited by /). The genotype of the Fx is Rrii and is white.
The F2 segregates as:
9 R-I- (white because / inhibits R) .
3 R-ii (colored because R can act with i).
3 rrl- (white because R is not present and also because / is present).
1 rrii (white because R is not present).
The phenotypes here add up to 13 white: 3 colored.12 This 13:3
phenotypic ratio is commonly called the inhibitor ratio, and the larger
number always represents the gene that acts as the inhibitor.
(5) Finally, there may be two dominants, each having the same
effect as the other, or as both of them together. In the common
shepherds-purse, the seed capsule is triangular in shape if the domi-
nant gene C or the dominant D is present — and also if both are
present. If both the rccessives of these genes, c and d, are homozy-
gous, the seed capsule is top-shaped. Dr. Shull of Princeton crossed
a variety cedd (top-shaped) with a variety CCDD (triangle-shaped).
From the triangular Fi (CcDd) he obtained in the F2:
9 C—D- (triangular — both dominant genes present).
3 C-dd (triangular — one dominant gene present).
3 ccD- (triangular — one dominant gene present).
1 cedd (top-shaped — double recessive) .
This adds up to 15 triangular: 1 top-shaped, giving a 15:1 ratio.
Other modifications of the ratio for two pairs of genes are: 9:6:1,
4:11:1,1:11:4,7:4:4:1,1:7:4:4,1:8:4:2:1.
When three genes with their alleles arc involved instead of two,
the ratios become still more complicated,13 and they will not be illus-
trated in detail here. The basic phenotypic ratio in the case of three
pairs of genes is 27:9:9:3:9:3:3:1. If the genes are considered as
ABC and abc, this ratio is 27 ABC: 9 ABc: 9 AbC: 3 Abe: 9 aBC:
3 aBc: 3 abC: 1 abc Some variations in this basic ratio produced by
the interaction of genes are 27:37, 27:9:28, and 63:1.
With more than three pairs of genes, the ratios become even more
complicated, especially if there are complex interactions among the
genes. It is evident that large numbers of progeny would be needed
to furnish a population with proportionate representation of all classes.
This need for large numbers of progeny is one of the difficulties in
animal genetics, where there is reason to believe that many genes,
interacting in a very complex way, are involved in what appears to
be a simple characteristic such as high or low milk production.
Backcrossing and the Backcboss Ratio
The backcross ratio is different from any of those previously
explained. The backcrossing technique consists chiefly in crossing
an Fi or later progeny back to one of the original parents or to an
individual recessive for whatever characteristic is under consideration.
11 In this ease also, the genes A1A2C are present in all the combinations, but they can be disregarded for
the sake of simplifying the analysis.
13 It will be noted in the above examples that three pairs of genes are sometimes involved, or even more,
but only two of them in both the dominant and recessive forms— that is, only two genes with their alleles.
FUNDAMENTALS OF HEREDITY
1431
The ratio is now being used to advantage by both the geneticist and
the breeder. The genetic make-up of the sow shown in figure 4 is
being tested by the backcross method. The geneticist uses it primarily
to test for linkage, a phenomenon explained in the next few pages.
The breeder uses it chiefly for two purposes — (1) to test whether a
given character exists in a pure (homozygous) form or in a hybrid
Figure 4. — A backcross ratio obtained in a litter from a cross-bred Berkshire-York-
sbire sow by a Berkshire sire. The ratio is 7 white: 6 black with some white. Two
of the latter type died. (Courtesy of Journal of Heredity.)
(heterozygous) form in one of the parents used in the backcross and
(2) to transfer a valued characteristic such as disease resistance into
an otherwise desirable variety that lacks it.
Suppose the breeder is dealing with a gene B, which produces
black in Aberdeen Angus cattle and is dominant to its allel b, which
produces red. He is not sure whether a given black animal is homo-
zygous or heterozygous, since both BB and Bb produce exactly the
same appearance. It is necessary for him to know, however, if he
wants to go on breeding pure black animals, because if he picks two
that are heterozygous the progeny will keep on segregating into blacks
and reds. In order to test the composition of an animal by this
method, he backcrosses it to a red individual, which, of course, has
the double recessive, bb. In the following generations one of two
tilings must happen. (1) All the progeny will be black, in which
case he knows that the animal he was testing must have been
homozygous, with the composition BB; for BB crossed with bb would
give every offspring a B and a b, or Bb, which would make every
animal black. (2) He might get an equal number of blacks and reds,
in which case he knows that the uncertain animal must be hetero-
zygous, or Bb; for Bb crossed with bb would give 1 Bb: 1 Bb: 1 bb: 1 bb,
or 1 black: 1 red. In the first case, he can keep on using the animal
he has chosen with the assurance that it will breed true. In the
1432 YEARBOOK, 1937
second case he will have to discard the animal and its progeny if lie
wants a herd pure for black.
Backcrossing, especially with plants naturally selfed, is seldom
resorted to for the purpose of determining whether they are homo-
zygous for a given gene. A few progeny from selfed plants are all
that are needed for this purpose, and, of course, in self -fertilized
plants it is much simpler to self a plant, grow a few progeny, and note
whether they segregate.
The 1 : 1 is a so-called backcross ratio, and it always appears when a
recessive is crossed with a heterozygous individual. The backcross
method therefore can be used to test the purity of any stock that
exhibits a dominant character. Backcross ratios also have been
worked out for two and three pairs of genes with their various inter-
actions. For example, in the case of two genes, A and B, with their
alleles, a and b, a heterozygous plant with the composition AaBb
crossed with the pure recessive aabb would give 1 Aa Bb: 1 Aa bb:
1 aa Bb: 1 aa bb.
The second use of the backcross is to transfer a certain valued
character to an otherwise desirable variety. Suppose the breeder
has a plant, A, that has good commercial characteristics but is
susceptible to a disease, such as bunt in wheat, and a plant, B, that
is worthless commercially but has bunt resistance, a dominant charac-
teristic. He crosses them, determines by suitable tests that the
Fj is resistant, inbreeds the Fi, and finds that the F2 segregates into
disease-resistant and disease-susceptible plants. He may backcross
the Fx to A, the double recessive for bunt resistance, and obtain the
backcross ratio of 1 resistant to 1 susceptible. A second or third
backcross may result in successfully retaining bunt resistance and at
the same time getting all of the desirable characters of the susceptible
parent, A. This backcross method is most successful when only one
dominant factor is involved. When the resistant reaction is recessive,
the backcross method of breeding is not so successful.
The important thing for the breeder to keep in mind here is that
B contributes worthless commercial characteristics as well as the
valuable one of disease resistance, and he must use skill in selecting
the particular disease-resistant plants for backcrossing on A. They
must have as many A qualities as possible, but, of course, lack
susceptibility to disease. Too much emphasis cannot be placed on
the importance of wise selection, especially in view of the fact that
usually many genes are involved in even the simplest characters,
rather than one dominant gene as in the above example.
LINKAGE AND CROSSING OVER
Although the discussion of ratios has dealt with genes, it should
be kept in mind that the genes are located in chromosomes. Just
what genes or chromosomes are, or by what means they exert their
fateful control over the characteristics of organisms, remains an
unsolved mystery of science. A chromosome may be thought of as
merely an aggregation of genes that stick together, like a chain
composed of a series of links, each somewhat different from the
others; or as a spiral of protoplasm inclosed in a matrix and divided
into sections, each section being a gene; or as a package containing
FUNDAMENTALS OF HEREDITY 1433
genes, like a druggist's vial containing pills. The point is that genes
occur in groups; and since they do, all of the genes on one chromosome
and the characters controlled by these genes tend to be inherited
together in what is known as linked-inheritance or linkage.
This is quite different from the idea held by Mendel, the father of
modern genetics. One of Mendel's laws was that all characteristics
assort independently of each other in inheritance — the theory of
independent assortment. As a matter of fact, apparently all the
characteristics Mendel studied in peas were so located that they did
assort independently. This was one of the most lucky of scientific
accidents. If Mendel had happened to deal with, linked characteristics
or those involving the interaction of genes, the results might have been
so complicated that ho could not have worked out his clear-cut laws
with the knowledge then available.
It was about 1905 when Bateson and Punnett in England discovered
characteristics that did not assort independently but remained
together in inheritance. As more evidence of this kind accumulated ,
various theories were proposed to account for it. The one finally
accepted was that genes for certain characteristics tend to be linked
together in what were called linkage groups. When Sutton in 1902
showed that chromosomes, the existence of which was known through
microscopic studies of the cell, play the dynamic role in inheritance,
it took only one more step to demonstrate that the genes in a linkage
group are carried on a specific chromosome and the number of linkage
groups and chromosomes is the same. Corn, for example, has 10 chro-
mosomes and 10 linkage groups. However, it is not possible by looking
at a chromosome to tell what genes it contains. The breeder must first
discover by actual test what characteristics tend to be linked together in
inheritance ; then he assumes that the genes determining these charac-
teristics are located in the same chromosome. In some cases, notably
the pomace fly and the corn plant, it has been possible by such breeding-
tests to assign a large number of genes to definite chromosomes.
But the situation is not so simple as this account might indicate.
A given gene does not always stay in the same chromosome. Kemp-
ton's article in the 1936 Yearbook described how a pair of homologus
chromosomes become twisted together during the formation of repro-
ductive cells, and how they may exchange equal portions during this
process. This is called crossing over, and it is equivalent to saying
that genes are exchanged between the two chromosomes. Thus the
original linkage group is changed and a new combination within the
linkage group is formed.
Suppose, to take an imaginary example, that on one chromosome
there is a gene A determining resistance to a certain disease and not
far from it a gene B determining broad leaves. In the corresponding
places on the homologous chromosome of the pair, there is a gene a
determining susceptibility to the disease and a gene b determining
narrow leaves. When these chromosomes segregate in inheritance,
every plant that is disease-resistant will have broad leaves and every
one that is not resistant mil have narrow leaves, since AB are located
in one chromosome and ab in one chromosome. But suppose that
in the reproductive cells of one plant, A and a are exchanged by
crossing over. Now Ab mil be in one chromosome and aB in the
338904°— 37 01 ++
1434
YEARBOOK, 193 7
^4
SZIIlfeffiPBS^fcl:¥3^
C\
D
Figure 5. — Models of chromosomes (A) broken into "chroma lids" (longitudinal
sections), showing two ways (B, C) in which the sections might wrap around one
another to produce the cross-overs shown in D. These chromosome models were
prepared by H. B. Newcombe and G. B. Wilson, of the Department of Genetics,
Met Jill University, Montreal, Canada. (Courtesy of Journal of Heredity.)
FUNDAMENTALS OF HEREDITY 1435
other, and there will be an opportunity to obtain new true-breeding
strains as a result of these recombinations. Figure 5 illustrates two
ways in which linkage groups are broken up by crossing-overs.
If the genes were very close together, the break would obviously
have to occur within a very narrow range to bring about an exchange,
and if they were next to each other it would have to occur exactly
between them. In other words, the closer the genes are on a chromo-
some the less likelihood there is that a break wall occur in the right
place to make an exchange possible. Geneticists have taken advant-
age of this fact to locate the position of genes on chromosomes without
actually seeing the genes. For example, if in a case of linkage 20 recom-
binations are obtained out of every 100 progeny, the two genes are said
to be located about 20 units apart on the chromosome, for the num-
ber of new combinations that are obtained when linkage is involved
depends upon the amount of crossing over, and this in turn depends
on the distance of the genes apart. In this case the genes would be
said to have 20 percent linkage, since the degree of linkage is desig-
nated by the amount of crossing over. Cross-overs are extremely fre-
quent and they may make breeding operations either more difficult or
easier, depending upon a breeder's desire for new combinations.
It is this physical fact that enables the geneticist to draw maps
showing the locations of genes on chromosomes. First, by appropriate
tests he determines that two genes, A and B, are located on the same
chromosome. Then, by breeding many progeny, he determines the
percentage of cases in which there is crossing over. By getting a
whole series of percentages for other genes — C, D, E, F, 6, H, etc. — in
relation to both A or B, he can determine how close these are to the
genes already located. Without ever seeing or identifying any of
the genes, he can determine mathematically their relative position
on the chromosome, and knowing the percentages of crossing over
between them, he can make a genetic map of a chromosome showing
the approximate locations of the genes. Other techniques are avail-
able for aiding in chromosome mapping.
Effect of Linkage on Segregation
The effect of linkage on segregation ratios may be illustrated with
the fowl. Landaucr and other investigators have demonstrated a
linkage between the creeper characteristic, which causes a marked
shortening of the long bones of the wings and logs (the fowl seems
to creep), and single comb. Rose comb (R) is dominant, and single
comb (r) is recessive. Creeper (Cr) is dominant, and normal or non-
creeper (cr) is recessive. To show how this linkage affects ratios an
example of an actual cross is given. One parent is normal and rose-
combed (cr cr RR), the other is creeper and single-combed (Cr cr rr).
The "creeper" parent is heterozygous for this condition because when
homozygous it is lethal, the embryos dying at about the seventy-
second hour of incubation. When these parents are crossed, one-half
cr R
of the Fi progeny have all four genes and are of the genotype -^— u.
or t
They are creeper and rose-combed because of the effects of the two
» This form is used in linkage studies to de-ignate which genes are linked. In this case cr and R are on
one chromosome and Cr and r on its homologue.
1436
YEARBOOK, 1937
dominants. Now the F/s of this type are backcrossed on double
recessives, that is, fowls with single comb and normal wings and legs,
cr r
cr r
If the creeper and single-combed condition were assorted inde-
pendently, we would get the normal backcross ratio — t creeper rose
comb: 1 creeper single comb: 1 normal rose comb: 1 normal single
■
cr R
cr R
(Normal, rose comb)
X
Cr r
cr r
(Creeper, single comb)
cr
Cr
(Doubl
creep
R
r
e heterozygo+e,
sr, rose comb )
cr R
cr r
(Normal, rose
Not Used
comb)
BACKCROSS
cr r
( cr r
(Double recessive,
normal, single comb)
cr R
Cr r >
(Double heterozygote
creeper, rose comb)
NONCROSS-OVERS
cr R Cr r
CROSS-OVERS
cr r Cr R
cr
(Nor
cr r
mal.rose comb) (Creeper, single
3219 comb) 3383
cr r cr r
(Normal, single comb) (Creeper,
9 rose comb)
15
Figure 6. — Test for linkage between rose-comb and creeper genes.
comb. But this does not occur. Instead the following proportions,
as shown by Landauer, are obtained — normal rose comb 3,219:
creeper single comb 3,383: creeper rose comb 15: normal single comb 9.
In other words, the normal rose comb and creeper single-comb birds
(parental types) are enormously in excess of the number expected.
The conclusion therefore is that the genes for normal wings and legs and
rose comb are on the same chromosome, and those for the creeper con-
dition and single comb are on its mate or homologue. When the chro-
mosomes segregate, the original combination of genes stays together,
and the few cases of the opposite combination are due to crossing over.
Without crossing over there could not be a creeper bird with rose comb,
or a normal one with single comb. Since 0.36 percent of the progeny
were of these types, there must have been crossing over between the
genes on the chromosome carrying the creeper rose comb characters
and their alleles in 0.36 percent of the gametes produced by the parent
heterozygous for both characteristics. This is referred to as 0.36 per-
cent crossing over. The matings and segregations are shown in figure
6. The proportions were obtained by Landauer.15
'» Landauer, W. studies ok the creeper fowl. v. the linkage of tiie csenes for creepf.r and
single couii. Jour. Genetics 26: [285J-290. 1932.
FUNDAMENTALS OF HEREDITY
1437
Figure 7. — A Plymouth Rock X Bantam cross, showing the barring gene, which is
sex-linked: A, Barred Plymouth Rock male parent; B, Rose Comb Black Bantam
female parent; C, D, first generation; E, F, G, H, second generation. Note that
barring is dominant (no black birds in the first generation) and a 3:1 ratio is
obtained in the second generation. There are, however, no black males in this
generation.
1438 YEARBOOK, 1937
Sex Linkage
A special case of linkage of particular importance is the linkage
associated with sex. Maleness and femaleness may be considered to
be characteristics just as truly as any others. If they were determined
exactly like other characteristics, however, the world would be very
different than it is. Suppose, to take a hypothetical case, that in
animals there was a gene Mfor maleness and an allel m for femaleness.
Whenever a male and a female — MM and mm — crossed, all the prog-
eny would be Mm. If M were dominant, they would all be males,
and no further reproduction would be possible. If neither gene were
dominant, all the progeny would be male-female, that is, hermaphro-
dite. Neither of these conditions occurs; instead, in the population
at large, males and females are born in approximately equal numbers.
If sex is determined by a gene, then, it does not operate like other
genes.
What actually does determine sex is another of the unsolved prob-
lems. It is known, however, that in many animals, sex is associated
with a chromosome peculiarity. In the dog, the cat, the pig, the
cow, the horse, and some other animals it is believed that the female
has one more chromosome than the male. In these cases the male
contains all the chromosomes contained in the body cell of the female,
and in addition one so-called X chromosome — not a pair. The female,
who has a pair of these X chromosomes, therefore always has one
more chromosome than the male with X. In some species of Droso-
phila, each sex has a pair of sex chromosomes, but they are different
in males and females. The odd chromosome found in the male is
designated as Y, so that the female has the composition XX
and the male the composition XY. In moths and birds, this
situation is reversed; the male has a pair of sex chromosomes called
ZZ and the female a single Z chromosome and a W chromosome.
The effect of a typical sex-linked gene-barring is shown in figures 7
and 8.
If sex is determined by a gene (or even a number of genes in com-
bination) on a sex chromosome, this arrangement would bring about
a segregation that accords with the facts. Let us say the female is the
one homozygous for sex, with the combination XX. The male is
heterozygous, with the combination XY. When the chromosomes
are reduced to form reproductive cells, every reproductive cell pro-
duced by the female has an X chromosome. Out of every two repro-
ductive cells produced by the male, however, one has an X chromo-
some and one has a Y. When a female cell met an X male cell, the
union would give the combination XX, which would become a female
organism. The female cell that met a male Y would have the com-
bination XY, which would become a male organism. In the WZ
type of sex determination males are homozygous, ZZ, and females
heterozygous, WZ. In both cases, males and females would be
produced in approximately equal numbers in the population as
a whole.
On the other hand, it is possible that sex is not determined by a
gene or genes. One theory is that it is determined by a certain
balance between all the chromosomes. There might well be a different
FUNDAMENTALS OF HEREDITY
1439
Figure 8. — The reciprocal of the cross shown in figure 7: A, Rose Comb Black Bantam
male parent; B, Barred Plymouth Rock female parent; C, D, first generation; E, F,
C, H, second generation. Note that in this cross the Black Bantam is a male and the
Plymouth Rock a female. The color factors show typical sex-linked inheritance — •
also what is known as "criss-cross inheritance." The latter is common in cases of
sex-linked inheritance. In this cross it is readily seen when the parental and first
generation types are compared. The black color of the male parent is shown only
in the female of the first generation and the barred characteristic of the parental
female is shown only in the male. In the second generation there is an equal number
of barred and black males and females, respectively.
1440 YEARBOOK, 1937
balance between an organism with one X or one Z chromosome and
an organism with two.
The sex chromosomes do more than determine sex (granted that
they do that). They also carry genes determining other less unique
characteristics such as barring, mentioned above. All the genes on a
sex chromosome, naturally, are in a single linkage group, and they are
associated with sex in inheritance. How docs this work out?
As an example, we might take the type of color blindness in man that
renders a person unable to distinguish between red and green. This
is a sex-linked characteristic; it is recessive and its determining gene
is located on the X chromosome. Now it has been shown that when
an X chromosome from a female cell combines with a Y in the male
cell, the result is a male organism, a son, On the other hand, when an
X from a male cell combines with an X from a female, the result is a
female, a daughter. This is another way of saying that a son can
receive the X chromosome only from his mother. The father's X
chromosome, on the other hand, can go only to the daughter. Thus
if the father's X chromosome contains the gene for color blindness,
it will go to his daughter but will be expressed only if both father
and mother transmit color blindness, since the two recessives must
come together. A son who is color blind could have inherited the
trait only from his mother, from whom alone he receives the X
chromosome.
A sex-linked characteristic, it. should be noted, is quite different
from a sex-limited characteristic. A sex-limited characteristic is one
that can be expressed by one sex only ; genes for it may be contained
in the other sex, but there is something that inhibits its expression.
Thus milk production may conceivably be inherited by both males
and females, but its actual expression is limited to females. Horns
in Rambouillet sheep are limited to males ; presumably there is some-
thing in the glands of the females that inhibits the expression of
horns, or perhaps something in the glands of the male that compels
the expression.
MUTATION OF GENES AND CHROMOSOMES
Other phenomena in addition to linkage and crossing over affect the
orderly transmission of a given sot of genes to offspring. In a broad
sense these phenomena may be classed as mutations. Gene muta-
tions involve a change in one or more genes, and they are now under-
stood to be caused in any one of a number of ways, as by heat reaching
the cell at a certain stage of its development, or by radiations of
certain wave lengths. In the latter case, it has been suggested that a
gene may be altered by a direct hit from an electric particle. In any
case, once a gene in a reproductive cell has mutated, it is thereafter
inherited in the new form, unless there is another mutation, It is
now commonly believed that many, perhaps most mutations, are
harmful to the organism.
Polyploidy brings about similar results. This is an increase in the
number of chromosomes in the cell, beyond the number that is normal
for the particular organism. Polyploidy frequently occurs when
organisms only distantly related are crossed. Presumably some or all
of the chromosomes from the two parents are so unlike that they are
FUNDAMENTALS OF HEREDITY 1141
unable to join in pairs, with the result that the number cannot be
reduced in the regular way when reproductive cells are formed. Tho
unpaired chromosomes are then left over to increase the regular num-
ber in the reproductive cell. Sometimes there is only one extra
chromosome, sometimes several, sometimes a whole extra set, or more
than one extra set. The phenomenon is treated at greater length in
Dr. Blakeslee's article, which appears in a separate of this Yearbook.
Naturally geneticists deal with other concepts besides Mendelian
ratios, linkage, sex-linked factors, lethal factors, multiple allelomorphs,
and other phenomena discussed in this article. They are paying con-
siderable attention to such things as chromosomal aberrations, trans-
locations, gene frequency, epistasis, and genetic tensions. As yet the
real importance of some of these newer concepts is not known. Some
may have a profound effect upon our knowledge of heredity, others
may be of little importance or may prove to be another way of stating
something that is already known.
The influence of environment on the expression of genes cannot be
ignored. For instance, in the case of animals it is only under certain
specific conditions of feeding, care, and management that genes for
rapidity and economy of gain, or for high milk production, can be
fully expressed. Taking production as an example, it is conceivable
that one strain of dairy cattle might have genes that would enable it
to produce at a high level on a diet that would reduce the production
of another strain to a very low level. In other words, there is no
universally optimum environment but an optimum for a specific gene
or genes. Temperature and nutrition have been found to produce
important effects even on such characters as coat color in rabbits and
rats. In certain kinds of rabbits low temperatures cause new hair to
come in black, whereas at higher temperatures the hair developing on
the same parts of the body is white. Thus it is evident that the
geneticist must consider the interaction of the genes with the environ-
ment in accurately describing their expression .
GENETIC ANALYSIS— PLANTS AND ANIMALS COMPARED
Intensive study of one animal form, the small pomace fly of the
genus Drosophila, principally by Thomas Hunt Morgan and his
students, has contributed very largely to the understanding of the
mechanism of heredity. Because of its short life span (it lives only
13 days on the average), its minute size, which permits hundreds
of flies to be grown in small vials, its small number of chromosomes,
and the presence in the species of a large number of different char-
acters, it has proved to be remarkably good material for genetic
study. But even with Drosophila, progress has been made at the
cost of much painstaking labor, and probably over 25,000,000 flies
have been raised and examined with meticulous care by students of
this species.
With the laboratory rodents and the fowl progress has also been
relatively rapid. The manner of inheritance of many traits, such as
color and various defects of structure and function, has been clearly
determined and it has been shown that the types of inheritance (inde-
pendent, linked, and sex-linked) are the same for these forms as for
Drosophila and many plants. And the masterful analysis by Wright
1442 YEARBOOK, 1937
of the results of many years of inbreeding of guinea pigs by the
Department of Agriculture has contributed much to what is known o)
the consequences of inbreeding, cross-breeding, and various othei
systems of mating, in both plants and animals.
With the larger animals progress has not been so great and the
criticism is frequently made that genetics has contributed little ol
importance to animal breeding. Much of this criticism is unjustified.
While the direct contribution to breeding practice has not yet been
great, genetics has contributed in a large way to an understanding of
the basic principles of breeding, and many concepts and superstitions,
such as telegony (an alleged effect of a sire on later progeny of the
same dam by another sire) and maternal impressions, have been dis-
carded as a result. It is now possible more readily to eliminate unde-
sirable hereditary traits from breeding stock. Application of this
knowledge has been employed especially in the elimination of such
abnormalities as lethal conditions, which have been found to be
inherited to some extent in most classes of animals.
The way in which the breeder of dairy cattle, for example, is today
shaping some of his breeding methods on the basis of genetic principles
is greater than is ordinarily realized. Within a period of 10 years
breed associations have adopted herd tests for the purpose of securing
records on all animals in a herd instead of the best ones only — a
recognition of the fallacy of selective testing. They are publishing
daughter-dam records for sires in recognition of the need of determining
the genetic make-up of outstanding sires. Great emphasis is being
placed on the sire that has proved through the progeny test that he
possesses a superior inheritance. Finally, many courses for the study
of the principles of Mendelian inheritance as applied to dairy cattle
are now held regularly.
In a negative way also genetics has contributed to practical breed-
ing. A knowledge of Mendelian laws has brought an understanding
of the consequences of the various systems of mating that have shown
the limitations of selection and certain other breeding practices.
In plant production it is usually possible to obtain large numbers
of progeny in a relatively short time and at little expense. The segrega-
tion by classes permits a determination of the ratios between them,
and this makes it possible to formulate a hypothesis to explain the
mode of inheritance and the genotype of the parents in a rather con-
clusive manner for most qualitative and some quantitative character-
istics. By the application of the principles of Mendelism it has also
been possible to work out the genetic basis for the more simply
inherited unit characters in animals, explain the occurrence of unex-
pected progeny, and predict the frequency with which they may be
expected in the future. With a background of such information the
breeder can decide whether he wishes to continue to breed a dam that
produces progeny meritorious in some such character as conformation
even though a certain percentage of her progeny have a very unde-
sirable characteristic and must be culled.
An understanding of the mechanism of sex determination was also
largely dependent upon genetic discoveries. Cytologistshadpostulated
the sex chromosomes as the basic sex-determining mechanism, but it
remained for the discovery of sex-linked characters and the genetic
FUNDAMENTALS OF HEREDITY 144-3
analysis of such characters to furnish final proof of the correctness of
this hypothesis. In poultry a largo number of sex-linked genes have
been studied and the facts obtained from some of theso studies have
been put to practical use in certain crosses to determine the sex of
chicks at the time of hatching. There is also some evidence that
certain genes affecting such characters as maturity and rate of winter
egg production are sex-linked, and, if these observations are sub-
stantiated, the information should eventually enable the poultryman
to incorporate these genes more easily into his flock.
Aside from such rapid-breeding forms as Drosophila, Mendeliau
analysis with animals in the sense of locating individ ual genes or finding
the number of genes that determine a given character will always be
more difficult than with plants, and a complete analysis with the larger
animals will probably never be made.
Why Progress in Animal Genetics Is Slow
There are numerous reasons why animal genetics has not made and
cannot hope to make as rapid progress in working out a complete
genetic analysis as has been possible with plants. Some of these
reasons will be discussed below.
(1) The male and the female are different individuals. Thus self-
fertilization, an important method used extensively in plant breed-
ing, is not possible in the breeding of livestock. The progeny always
has genes contributed by both parents, and since each parent has a
different set of genes this greatly retards the rate of production of
genetically pure forms. Progress in plant genetics has been aided by
the ability to determine the genotype through the segregation of prog-
eny produced by self-fertilization. The mating of brother and sister
or of a parent to his or her offspring is an approach to the self-ferti-
lization method used by the plant breeder, but the progeny test, as
showTi in figure 9, is being more and more widely used as a method
of determining the genotype in animal breeding. _
(2) The rate of maturity and breeding is relatively slow. In most
plants with which genetic progress has been made, it is possible to
obtain at least one generation a year. An animal— for example, a
calf — must often be kept 2 years before it produces any progeny. In
turn, the female progeny must be kept 2 years before it produces milk,
in case this is the character to be measured. Another year is required
to get the complete lactation. If the first calf happens to be a female,
at least 5 years are required to get the first record of production on
dam and daughter. Further records on other progeny will be needed
to determine the genotype of the dam.
(3) The number of progeny of any pair of individuals is usually too
small to be sure of the genotype of the parents. Earlier in this article,
it was pointed out that the genotype of the individual is determined
by the type of progeny it produces. Backcrossing to the homozygous
recessive strain was found to be the easiest way to determine the
genotype. Applying this to a dairy animal, let us assume that dom-
inance is involved in inheritance of milk yield. If the animal in ques-
tion were a cow and if a bull carrying the recessive factors were avail-
able, so many years would be required to get sufficient milk records
on the female progeny of this cow in order to have data on which
1444
YEARBOOK, 1937
sound conclusions might be based regarding the genotype of the dam
that the procedure would be impracticable. Moreover, only half of
the calves would be females, and not all of these would be raised so that
milk records could be obtained for them.
A case of polled condition in cattle involving a single pair of genes
will help to explain this, although it should be kept clearly in mind
Figure 9. — Brother and sister malings are the closest approach that the livestock
breeder can make to the self-fertilization method used by the plant breeder. Here
is shown a cross-bred Berkshire-Yorkshire sow with pigs by a Yorkshire-Berkshire
sire. The ratio is 7 white pigs: 2 black with some white. Both of the latter type
died. (Courtesy of Journal of Heredity.)
that milk production is probably due to several pairs of genetic factors.
In cattle the polled condition (P) is dominant and horns (p) recessive.
Suppose a polled cow produces a polled heifer calf, but in later matings
produces a honied bull calf (simple recessive). It is desired to know
if the genotype of the polled heifer calf is PP or Pp. In the former
case, the heifer might advantageously be kept for breeding purposes,
but in the latter case, it might be undesirable to do this in view of the
fact that she would transmit the gene for horns to one-half her progeny.
Of course, she could be used for breeding purposes and produce no
horned calves if mated to a PP sire even though the gene for horns
would be transmitted to one-half her progeny.
FUNDAMENTALS OF HEREDITY 1443
After reaching sexual maturity, the polled heifer (P-) is mated to
a horned bull (fp). If she carries horns? one-half of the calves should
be horned. If all the calves are polled, it will be necessary to produce
four to six calves to obtain a reasonable degree of assurance that the
polled heifer does not carry the gene for horns. Here, it has taken
several years to determine the genotype of the polled heifer for one
pair of genes, which may be expressed in calves of either sex. Con-
sider how much more complex the problem becomes when the charac-
teristic concerned is due to the action of several pairs of genetic factors,
expressed only by females and not by them until they have reached
sexual maturity, as in the case of milk production or egg production.
Further, a cow that has produced four to six calves will not be available
very much longer for breeding purposes.
The case of horns involving the action of only one pair of genes is
the simplest kind that will be encountered. Suppose we are con-
cerned with the inheritance of characters behaving like comb type in
fowls. Here, two pairs of genes are involved. The double recessive
for both pairs of genes results in a single-combed bird. The dominant
gene of one of the pairs produces pea comb and the dominant gene of
the other, rose comb. When the dominant genes are present in both
pairs, a walnut comb results. _ The ratios to be expected in cases
where two pairs of factors are involved have been pointed out in the
previous discussion. At least 16 individuals would be necessary to
represent the segregating groups in the proportion in which they occur
in the F? generation.
Warwick has suggested that inguinal hernia in swine is due to the
operation of at least two pairs of recessive genes. This characteristic
does not ordinarily appear in sows, although sows transmit the genes
for it. To determine whether a sow transmits hernia, it would be
desirable to mate her with a herniated boar (backcross) and ascertain
if any of her male pigs were herniated. The ratios expected would
depend somewhat on the genotype of the sow. If she did not transmit
both recessive factors, none of the pigs would be herniated. Still we
would not know whether she transmitted the recessive gene of one of
the allelic pairs. If she were heterozygous for one pair of factors and
homozygous recessive for the other pair — that is, with the constitution
Aa bb — one-half of her male progeny from the herniated boar would
have hernias. If she were heterozygous for both pairs of factors, with
the constitution Aa Bb, one-fourth of the male progeny would be ex-
pected to have hernias. Modifying factors may still further compli-
cate the situation. Therefore, it is usually considered advisable,
instead of testing the individual concerned in a definitely planned
experiment, to go ahead with the usual breeding operations, and if the
parents produce herniated pigs, to assume that both parents transmit
the undesirable characteristics, and discard them so as to eliminate
the possibility that their progeny will carry an undesirable recessive to
still more descendants.
The difference between high and low milk production certainly is
due to the operation of several pairs of genetic factors. Estimates of
different investigators have ranged from 3 to nearly 20 pairs of genes.
This increases the number of animals necessary to give a complete
segregating population beyond any possibility of a single pair of par-
1446 YEARBOOK, 1937
ents producing sufficient progeny to determine the genotype accu-
rately. With 10 pairs of genes, which has been suggested by Turner
as the minimum number controlling milk production, 1,048,546 animals
would be required to give a complete F2 population and 1,024 progeny
to give a complete backcross generation. Obviously, it is impossible
to get enough progeny from matings between the same two individuals,
yet genotypes of a pair cannot be ascertained otherwise. Moreover,
to allow for chance variations, it is usually considered necessary to
have at least three times as many individuals as are needed for the
complete segregating population.
(4) Animal-breeding research is ver3r costly. It is much more ex-
pensive to produce a single individual than would be required in the
case of a single plant. Special care, feeding, management, and ade-
quate space are required. The progeny of any single mating is small
as contrasted with the large number of seeds produced by most plants.
The cost of keeping the numbers of animals needed to work out a
rather complex ratio involving several pairs of genetic factors is almost
prohibitive.
(5) Many of the characteristics of economic importance do not
readily group by classes. Color, horns, and many of the more obvious
characteristics are inherited in a relatively simple manner, but the
genetic basis for characteristics concerned with the production of
milk, meat, eggs, wool, etc., is more complex. The genes determining
milk-producing capacity may act in a cumulative manner, or domi-
nance may govern their expression to a greater or lesser extent. It
is probable that if several pairs of genes are involved, various kinds of
gene interactions occur, which adds to the complexity of determining
the mode of inheritance of such characters.
In cases where a large number of genes are operative in determining
a quantitative characteristic such as yearly butterfat production, dif-
ferent genotypes may give rise to the same phenotype. For example,
with genes A, B, and C, assuming that A was responsible for 150
pounds; a, 25 pounds; B, 75 pounds; b, 25 pounds; G, 100 pounds; and
c, 25 pounds, one might have an individual producing 350 pounds of
butterfat with the genotype Aa bb Cc, or aa Bb CO. Such conditions
make the identification of the effect of the different genes very difficult,
if not impossible. When a large population is needed in order to have
representatives of the different types, the difficulties encountered in
studying quantitative characters, which includes so many of those of
economic importance, are apparent.
(6) Modifying factors, which play an important part in the inheri-
tance of many characters, tend to spread the classes so that one grades
into another. The mode of inheritance of these factors is similar to
that of the other genes concerned, yet their presence may completely
change the results obtained. For example, in some poultry there is
an inhibiting gene preventing the appearance of any color. The
presence of this gene results in the white of the White Leghorn. Yet
the White Leghorn may carry many color genes, expression of which is
inhibited until suitable crosses with other breeds permit their expres-
sion in the absence of the inhibitor. In quantitative characters, such
genes may increase or reduce the expression of another gene, as in the
case of the relative amounts of color and of white in spotted animals.
FUNDAMENTALS OF HEREDITY 1447
(7) Environmental effects may prevent the expression of certain
genes. The characters of economic importance in livestock are in-
fluenced to a considerable extent by environment. For example, it
is well known that a dairy cow may not produce up to her inherent
capacity if she receives an insufficient food supply. To be sure, the
plant is subject to environmental influences also, but ordinarily plants
are placed under more adequate control, or at least the effect of en-
vironment can be evaluated more easily and at less expense. The
identification of the role of the individual gene becomes practically
impossible unless the environmental effects are kown and kept
constant.
Breeding Programs and the Future of Animal Genetics
Fortunately there is a brighter side to this picture. It is not neces-
sary to know how many genes affect each character nor the effect of
each individual gene entering into the final expression of a given quan-
titative character in order to make progress in animal breeding. Again
we may use the inheritance of milk yield as an example. We now
know that the cow that produces 350 pounds of butterfat cannot be
depended on to transmit the inheritance for that level of production
to all her offspring. But if a herd of such cows are mated to a certain
sire and all or most of the daughters produce 400 to 450 pounds of
butterfat under the same environmental conditions, then we know that
the sire possesses a genotype for a higher level of production than did
the dams to which he was mated. Furthermore, the continuous use
of sires that have demonstrated through the progeny test that they
possess a genotype for higher levels of production will result in con-
centrating the factors determining the higher levels of production in
the germ plasm of the herd. (The genotype of the dam as well as
that of the sire can be determined by the progeny test, but the time
required is so much greater and the inheritance of the individual
dam is transmitted to so few progeny that it is much more feasible to
work through the sire.) Thus progress is made in animal breeding
by working with the end result of numerous genes, even though the
number of genes involved is not known, nor the part that an individ-
ual gene plays in bringing about the end result.
Kesearch work is gradually bringing about a knowledge of the extent
to which some of the more common environmental variations may
influence the expression of a character. In dairy cattle, for instance,
knowledge is being accumulated concerning the effect on production
of a number of factors, including age; the use of box stalls as compared
to stanchions; the number of mukings per day; different ratios of grain
or the all-roughage ration. Such information helps in evaluatmg a
sire when, as frequently happens, the dams and daughters did not
make their records under entirely comparable conditions, since suitable
corrections can be made. However, more knowledge is needed to
solve many of the problems that confront such a system of breeding
as that outlined above. For example, when a sire is mated to dams
with a very high level of production and the daughters of that mating
have a somewhat lower level of production than the dams, it is difficult
to determine what the genotype of the sire is, unless he has also been
mated to cows possessing a lower level of production to see whether
1448 YEARBOOK, 1937
he raised it or not. Likewise, when a sire is mated to dams with a
level of, say, 350 pounds of butterfat and his daughters prove to be
considerably above that level, it is impossible to know whether he has
a genotype that will enable him to improve the germ plasm of a herd
of cows with an average level of, say, 600 pounds, perhaps made under
different environmental conditions than the record of the first herd.
The so-called provcd-sire system of breeding progresses most rapidly
where (1 ) the sire is mated at an early age to a large group of females,
so that there is a sufficient number of female progeny to make possible
the evaluation of his genotype before he reaches too advanced an age;
(2) there is no selection of the daughters and their dams on the basis of
high records; (3) records are made \mder environmental conditions
that are comparable for both daughters and dams; and (4) environ-
mental conditions are sufficiently good to enable the animals to express
levels of production approaching their inherent capacity.
The difficulties encountered with the breeding of larger animals as
contrasted with the progress made with insects, plants, and laboratory
animals lends support to the idea that it never will be practicable, or
perhaps possible, to identify the action of each gene in animal breeding.
Genetic principles may be worked out with laboratory animals or
insects that may be kept at much less cost and will reproduce rapidly.
In experiments writh larger animals, the genes will not necessarily have
to be identified, but evaluations may be made by methods analagous
to those employed in proving dairy sires in order to determine trans-
mitting ability. It makes little difference to the dairyman whether
350 pounds of butterfat is produced because the animal was of the
genotype Aa bb Cc, aa Bb CO, or what not, except that crosses of strains
of certain genotypes would be expected to produce animals superior to
either parent. In practice, it probably would be more satisfactory to
test the complementary action of the genes from different animals by
trial crossing rather than to attempt to discover the specific genes
carried by each animal and the part they play in determining and
transmitting characteristics.
The complementary action of unidentified genes has been success-
fully used with corn. Strains have been inbred to insure that they
were homozygous, and by trial and error it has been found that the
progeny from certain crosses are superior to ordinary varieties. The
practice of similar methods would appear to offer promise in animal
breeding, though experimental evidence will be needed in order to
determine whether the results would be superior to, or more reliable
than, those obtained by the proved-sire system. Then too, when close
inbreeding in animals results in a loss of efficiency in characteristics
of economic value, as is often the case, the cost of maintaining these
closely inbred strains for crossing will be much greater than is the
case with inbred strains of corn. Not all inbred strains of corn respond
with marked hybrid vigor when crossed, and many strains have to be
crossed in order to find those that result in increased yields. If this
same amount of work is necessary with livestock, the expense of this
method of breeding appears quite formidable, particularly in the case
of cattle and horses. With smaller animals, like swine, the limitation
is somewhat reduced and in fact experimental work of this kind is
rapidly getting under way.
FUNDAMENTALS OF HEREDITY 1449
With the larger animals it is apparent that breeding progress will
come about largely through what might be called a mass determination
of the genotype. By the application of the progeny test and the use
of sires proved in that manner, it will probably be possible to produce
strains of animals in the various species containing combinations of
genes that will give better average production than any, strains now
in existence. This method, combined, perhaps, with some inbreeding
to produce greater homozygosity of the desired characters, holds great
promise for the improvement of all forms of livestock. Progress
obviously will be slow, however, owing to the difficulties that have
been enumerated.
That genetics has not contributed more to livestock-breeding prac-
tice is not surprising. As a science it is less than 40 years old, and
many of the basic discoveries have been made in the last 20 years.
But the principles underlying breed improvement have been deter-
mined, and progress in the future should be more rapid. While
Mendelian analysis has taken first place in some forms of life, it is
certain that with the larger animals such an analysis will remain
secondary to the testing of various breeding systems with the aim of
synthesizing better and better strains.
138904°— 37 92
VEGETATIVE
REPRODUCTION
■
J. R. MAGNESS, Principal Pomologist,
Division of Fruit and Vegetable Crops
and Diseases, Bureau of Plant Industry
J\hh of the important fruit-crop plants in the United States, many
of the ornamentals, a few crops like potatoes, and some of the nut
and forest trees are multiplied or propagated for commercial production
by vegetative means. This means that a new plant is developed
from a vegetative portion of a mother plant, such as a cutting or bud,
instead of from a seed, as is the case with most of the cereal, forage,
and vegetable crops. This fact is extremely important from the stand-
point of the principles and methods employed in the improvement of
fruit crops by breeding.
As was explained in detail in the article on Heredity Under the
Microscope, in the 1936 Yearbook, the seed in the ordinary plant
develops from a single cell, the fertilized egg, which has received in
the fertilizing process chromosomes from both the female or seed
parent and the male or pollen parent. These chromosomes transmit
the hereditary factors or genes from both parents, and the offspring
that develops from this cell, therefore, inherits the characteristics
of both. If the germ cells from the two parents carry genes that are
alike for all characteristics, the plants that develop from the seeds
will be very similar to these parents. On the other hand, if the parents
transmit unlike genes for various characters, many of the offspring
will vary widely from either parent because of the effects of dominance,
recessiveness; or modifying factors.
In vegetative propagation the new plant also develops from a single
original cell. Although the bud or other propagative tissue may con-
sist of thousands of cells, at one stage of its development only a single
cell was involved. This cell carries the same genes as the mother
tissue from which it was developed, and the genetic characteristics
of the new tissue correspond to those of the mother plant, except in
the case of vegetative mutations, to be discussed later in this article.
From the hereditary standpoint it may be said that the vegetative
offspring of a plant is a part of that plant itself rather than a new
individual.
The Winesap apple, for example, originated as a seedling about 200
years ago. The original tree has probably been dead for more than a
century. Before that tree died, however, buds taken from it were
grafted into other apple roots and these buds developed into new
individual Winesap trees, the tops of which are genetically a continua-
tion of the parent trees. Many generations of trees have been grown
from this original Winesap, yet the characteristics of the Winesap
1450
VEGETATIVE REPRODUCTION 1451
trees and fruits today are but little, if at all, changed from those of
the original tree.
Varieties of European wine grapes exist today that are believed to
have originated several hundred years ago. These grapes have come
down to the present time practically unchanged in character because
vegetative portions of the vines rather than the sexual portions or
seeds have been used for propagating them. The Wilson straw-
berry, originated in 1852, is still grown to some extent in Oregon. It
has been propagated by runner plants ever since its origin and after
many vegetative generations is today apparently similar in all respects
to the parent plant.
CELL DIVISION IN VEGETATIVE TISSUES
In many respects the division of a cell to form two daughter cells
in vegetative tissue is quite similar to that described in the article on
Heredity Under the Microscope for germ cells. Each vegetative cell
consists of the cell wall, the cytoplasm, and a nucleus. The nucleus,
while the cell is in the resting stage — that is, not in the act of dividing
— contains numerous chromatin granules, just as the germ cells do.
In the beginning stages of cell division these chromatin granules
collect in threadlike bodies, which are the forerunners of the more
definitely organized chromosomes. These threadlike bodies are
usually more or less separate, though in some cases they appear to be
arranged end to end. Later they break up into independent chromo-
somes.
At this stage one very important step occurs that does not occur
in the same way in the germ cell. After the chromosomes are formed
in the vegetative cell, each chromosome appears to split longitudinally
into two parts, giving twice the original number. Each of these parts
appears to function as an independent chromosome. After that, the
process is like that in the germ cell. The two halves of each original
chromosome migrate, one to each of two poles on opposite sides of the
nucleus. These two groups of chromosomes, one at either pole, now
reorganize as separate daughter nuclei, each similar to the original
one. A cell wall is formed between the two daughter nuclei, and there
are two complete cells instead of the original one. Each of these
cells, however, has the same number of chromosomes as the original,
whereas if they were germ cells they would have half the original
number.
Apparently the genes, which are the carriers of hereditary factors
in the chromosomes, are also divided in this process of longitudinal
splitting of the chromosomes, and this gives each daughter cell exactly
the same hereditary factors. If it were possible at this stage to isolate
each daughter cell and develop from it a wholly new individual, the
new individuals would be exactly alike genetically and both would be
exact genetic replicas of the parent plant.
However, it is, of course, never possible to grow two plants and
have them exactly alike even though they have exactly the same
genetic make-up. The final size and shape of a plant depends upon
two factors — its genetic make-up and its environment. It is never
possible to have exactly the same environment for two individuals.
Variations in nutrition, light exposure, moisture relations, or in other
1452 YEARBOOK, 1937
factors in the environment will always make some difference in the
ultimate development of individuals. Genetically, however, plants
that develop from these vegetative daughter cells will have the same
make-up that was contained in the parent cell from which they were
derived.
But, even in the most nearly perfect mechanism there is always
the possibility that it may not function exactly the same in every
case. Thus in the division of thousands of cells there is the possibility
that certain cells may not divide so as to give the daughter cells exactly
the same genetic make-up. In the splitting of the chromosomes, for
example, it might occasionally happen that certain genes would fail to
split, in which case one daughter cell might have a certain gene while
the companion daughter cell might lack it.
There is ample evidence in the horticultural field that abnormal cell
division occasionally occurs in the vegetative development of the plant.
TV hen it does occur, if the cell concerned is one from which major
portions of the plant develop, a so-called bud sport branch may
arise, showing a different character, and this sport or mutant may be
propagated by vegetative means. Thus, in an apple variety a gene
for fruit color may be added to or taken from a chromosome in a divid-
ing cell at the tip, giving rise to a "color sport branch."
In certain plants shoots arise, not from the continued division of a
single cell at the tip, but rather from the divisions of many cells in a
group. In such cases the mutant cell may affect only one portion of
the new shoot. This may represent a sector running throughout the
length of the shoot, in which case we have what is called a sectorial
chimera or variation. Buds taken from that particular section will
develop into plants showing the variationthroughout.
Also, in certain plants mutations occur involving only the outer ring
or rings of cells on the stem. These are termed periclinal chimeras.
The thornless sports of blackberries are of this type. They reproduce
true to the thornless type from propagations made from stem tissue as
tip layers, since in this case the new bark develops as a continuation
of the old, but not from root tissues, because in this case all the new
tissues originate from deep-seated cells that carry genes for thorniness.
These mutations in the vegetative tissues may involve only one gene
or they may involve several. Thus, not only color of fruit might
be modified, but shape, texture, season of ripening, or chemical compo-
sition might be affected by such imitations. At rare intervals a
doubling of some or all of the chromosomes may occur without nuclear
division, followed by regular division thereafter. Such a mutation,
which produces a permanent increase in the number of chromosomes
in each cell, often results in marked variations in vigor, fruit size,
quality, and other factors in the mutant tissue. The variations can
be reproduced in practically identical form by vegetative propagation.
It is noteworthy, however, that in most plants these vegetative
mutations occur very infrequently. Ten thousand buds taken from a
grape variety may develop into as many individual vines with hardly
an observable variation that can be attributed to a lack of perfectly
regular genetic reproduction in the vegetative cells. The remarkable
feature is not that occasional irregular cell divisions occur, but rather
that the irregularities are so rare.
VEGETATIVE REPRODUCTION 1453
This fact is of tremendous importance from the standpoint of
establishing fruit varieties. Once an individual plant is obtained,
as a result either of hybridization or of selection, it is possible to
reproduce that plant almost exactly by vegetative propagation.
With seed-propagated plants, on the other hand, before a new varie-
ty can be established it is necessary not only to secure an individ-
ual plant that has the characteristics desired but to follow this with
selfing or inbreeding until a group of plants is secured of proper
genetic purity to come true in large proportion from seed. This
long process of breeding to secure varieties that come true from seed
is not necessary in the improvement of plants that are vegetatively
propagated.
The fact that all fruit varieties are vegetatively propagated, how-
ever, is not an unmixed advantage to the breeder of fruit crops. The
very fact that individuals can be reproduced by vegetative means
has resulted in the selection of varieties without any regard to how
nearly they reproduce true to type from seed. Furthermore, up to
the present time much less study has been made of the hereditary
make-up of our fruits as a group than of many of the seed-propa-
gated crop plants. We can. usually judge what characters will be
transmitted in inheritance, in the case of seed-propagated varieties of
sufficient purity, by the type of parent material. This is not always
true of vegetatively propagated plants.
The Northern Spy apple, for example, in its vegetatively propagated
form is large-fruited. Seed of this variety, however, produces mostly
smaller apples. A particular variety of grape may be black, yet,
seed planted from tliis variety may produce white, red, or black
grapes. The possibilities of our horticultural varieties as breeding
stock can be determined only by trial. In actual experience it has
sometimes been found that a variety having very valuable character-
istics when vegetatively propagated does not tend to reproduce these
characteristics in the seed offspring. On the other hand, certain
rather mediocre varieties may prove superior as parents for the
development of improved sorts by breeding methods.
Most of our tree fruits and some ornamentals are propagated by
budding or grafting the desired variety on the roots of the same or
closely related species. With our tree fruits, these roots are mainly
developed from seedlings. With grapes and roses, the roots are also
propagated vegetatively.
There is much need for investigations in the United States to
determine the best rootstock to use with the various fruit and nut
varieties. The use of the best rootstocks might greatly improve the
vigor and longevity of orchards under certain conditions. For ex-
ample, peach rootstocks resistant to nematodes in the South and in
parts of California should result in longer lived and more vigorous
trees. The development of grape rootstocks resistant to phylloxera
has saved the vinifera grape industry of southern Europe and in
parts of California. The development of apple stocks resistant to
woolly aphis would be a great, asset to apple growing in many parts
of the world. The characters of the rootstock are second only to the
characters of the variety in determining successful production of
manv of our fruit varieties.
1454 YEARBOOK, 1937
DO VEGETATIVELY PROPAGATED VARIETIES "RUN OUT"?
Closely allied to this discussion of the relation of vegetative propa-
gation to breeding is the question of whether or not such vegetativelv
propagated varieties last indefinitely. It was long held, even by
horticultural authorities, that after a few generations of vegetative
propagation, varieties gradually lose their superior characters, be-
come less vigorous, and decrease in value until they are abandoned
as commercial sorts. Andrew Knight, of England, probably the
Figure 1. — Potatoes in middle row were propagated from seed pieces infected with
curly dwarf, one of the potato virus diseases. The rows on each side were propagated
from healthy seed stock. Virus diseases transmitted by vegetative propagation
undoubtedly account for the so-called "running out" of many varieties.
greatest horticultural authority at the beginning of the nineteenth
century, believed that varieties "run out" under vegetative propaga-
tion. Potato growers strongly held to this view until recent years,
because their varieties appeared to deteriorate rather rapidly. Until
recently, most growers of vegetatively propagated plants believed
that such propagation is a weakening process and that new varieties
propagated from seed must be developed frequently if vigor, quality,
and productiveness are to be maintained.
It is true that many vegetatively propagated varieties are popular
for a plant generation or two and then pass out of the trade. However,
there is no evidence that varieties have become progressively weaker
owing to repeated vegetative multiplication. In some cases, varieties
develop diseases that may be carried from the mother plant to the
daughter through the bud, cutting, or runner plant. This is espe-
cially true of the virus group of diseases, and many varieties may have
disappeared because of such transmitted infection. A number of
virus diseases are known that affect potatoes (fig. 1), strawberries,
raspberries, and other vegetatively propagated plants. An under-
VEGETATIVE REPRODUCTION
1 !.-).',
standing of these diseases has come only in very recent years. Prior
to a knowledge of these diseases it was natural that the grower would
assume that the weakened or malformed plants, resulting from vegeta-
tive propagation from infected parent material, were "running out."
By keeping the parent material for vegetative propagation free of
disease, such deterioration can be prevented.
Other varieties are discarded because of changing preferences on
the part of the consumer or because the plant may not be sufficiently
Figure 2. — Winesap apple trees still vigorous, productive, and producing good-
quality fruit. The leading commercial apple variety of the United States, this variety
has been propagated vegetatively since its origin almost 200 years ago.
hardy, vigorous, or disease-resistant to meet new demands. The
Early Crawford peach is an excellent example of tliis. This variety,
which originated about 100 years ago, is still identical with the original
in all the characters that made it very popular 50 years ago. Today,
however, it is little grown, despite its high quality. Other varieties
have developed that are heavier yielders, that can be shipped and held
on the market in better condition, and that are somewhat hardier.
The Esopus Spitzenburg apple is another example of a very high-
quality dessert variety that is disappearing from American orchards
because the tree is not hardy and is particularly susceptible to many
diseases. Yet there is no reason to believe that this variety as propa-
gated today is in any way inherently different from the parent tree
of 150 years ago. It is still a vigorous tree and productive, if pro-
tected from low winter temperatures and diseases. In contrast, the
most extensively grown apple in the United States today is the Wine-
sap (fig. 2), which is believed to have originated at least 200 years ago.
1456
YEARBOOK, 1937
Occasionally a variety may show a lack of stability under vegetative
propagation, which leads to an abundance of vegetative mutations
generally of one particular type. For example, in a number of straw-
erry varieties under vegetative propagation there has been a marked
tendency to mutate to a yellow-foliage form (fig. 3). Such wholesale
Figure 3. — The yellow-plant mutation (center) in the Blakemore strawberry. This
mutation occurs very frequently in this variety and will result in the commercial
deterioration of the variety unless propagating material is carefully selected to avoid it.
mutation has occurred in the Howard 17, or Premier, variety, and in
recent years it has occurred in the Blakemore. Apparently some
.unstable gene occurs in the make-up of these varieties that develops a
very high proportion of mutations. In certain strawberry varieties
this has resulted in their passing out of commercial production.
The Washington Navel orange also appears to develop a rather
large number of mutations under vegetative propagation. In most
cases careful selection of the parent stock will permit the maintenance
of such varieties. Perhaps this marked tendency to mutate, which
occurs in a very few vegetatively propagated varieties, most nearly
represents "running out" in the sense that the term has usually been
employed. Even in this case, however, the selection of true-to-type
parent material will usually maintain a variety indefinitely.
A CHRONOLOGY
OF GENETICS
ROBERT COOK, Editor, Journal of Heredity
_L HE science of genetics as of 1937 has a long and rather involved
history, which has not proved easy to treat as a chronology. Made
up as it has been of a fusion of diverse specialties which have developed
at different rates, a simple chronological listing of discoveries and
developments necessarily gives a rather fragmentary picture of the
unfolding of the modem science of heredity. Various plans were
considered to avoid this difficulty, but the most satisfactory treat-
ment seemed to be to combine everything in one simple chronology,
which branches out into occasional summary paragraphs to suggest,
without prohibitive chronological detail, the recent developments,
and to buttress this with a graphic genetic family tree to give visually
the relations of the various main components that have gone to make
our modern genetic organism. The difficulties that have been en-
countered in determining many of the "first discoveries" noted in
this chronology suggest that an exhaustive history of genetics will
soon be necessary. Roberts and Zirkle have recently summarized the
early publications on plant hybridization, but a connected story of
the development of genetics as a whole remains to be written.
The compiler takes this opportunity to acknowledge invaluable
help and suggestions from a group of about 35 geneticists who gener-
ously read and commented on a mimeographed first draft of this
chronology. In the time allotted it would have been impossible
without this freely given aid to have done nearly so complete a job
as is here presented — which remains, it is regretfully realized, even
with this help, only a very rough sketch. It was the wish of the
editors to present in this Yearbook a bird's-eye view of genetic progress
pointing out the important highlights but not in too much detail.
Without overburdening this chronology with bibliographic refer-
ences, and thereby reducing its readability to a minimum, and at the
same time to make available authority for the dates given, a condensed
list of references is included. A more detailed bibliography giving
titles of articles cited and authors in full has been deposited in manu-
script form in the United States Department of Agriculture library.
Copies of this bibliography may be obtained from the library through
the Biblioform Film Service. It is hoped that this will make all
references reasonably easily available to all who are interested.
BEGINNINGS
First hybrids were probably of species and varieties of cattle and clogs,
by Neolithic people, possibly as much as 10,000 to 25,000 years ago.
1457
1458 YEARBOOK, 1937
Several varieties of dogs and of cattle and sheep are depicted on
Egyptian and Babylonian monuments of 5,000 years ago. The
bisexual nature of the date palm was also recognized by the early
Babylonians and Assyrians 5,000 years ago. Mules are mentioned
in Homer (B. C. 800) and in Herodotus (fifth century B. C). The
writings of Aristotle and other ancients abound in a wealth of observa-
tions, many of them confirmed by modern experiments. Unfortu-
nately they also contain much very fanciful material — descriptions
of astonishing and highly improbable hybrids between a great variety
of animals. This very likely meant no more than that monstrosities
were ascribed to hybridization, as the ancients generally looked upon
the process of hybridization with abhorrence. Even angels and
demons were reported on excellent authority to have produced hybrid
progeny whose astonishing characteristics were limited only by the
imagination of the narrator. Theories of heredity were not lacking,
but facts that might verify these purely speculative fabrications were
held in small esteem. Vergil tells us that the chosen seed, improved
through years and labor, was seen to run back, unless man selected
by hand the largest and fullest ears (Georgics I: 197). Columella
and Varro also affirm the need for selection of cereal varieties.
Theophrastus and Pliny discussed sex in plants but reported no
experiments.
Allusions to the tendency of "like to beget like" are not hard to
Ibid in ancient literature. The Middle Ages enthusiastically added
much to the fables but nothing to the factual background of the an-
cients. In spite of the lack of theoretical background, animal breed-
ing, based on traditional methods ("like begets like" and various
approximations to the progeny test), excellently exemplified in the
New Testament aphorism "by their fruits ye shall know them",
(Matthew 7: 20) made very considerable progress.
That primitive men have been not only persistent plant breeders but
fairly successful ones is evidenced by the remarkable progress made in
plant breeding in many parts of the world. The ancient Chinese are
credited with breeding superior varieties of rice and hybrid flowers.
Russian, workers have recently published most interesting accounts
of the wheat breeding on the southern slopes of the Caucasus Moun-
tains. We have only to consider Indian corn, and the remarkable
varieties produced by the American Indians, to realize the fact that
man has been breeding plants from very early times.
The records left by the Babylonians and Egyptians leave no doubt
that at least 5,000 years ago distinct breeds of domesticated animals
were recognized. Certain of the types depicted on those ancient
monuments bear a remarkable resemblance to modern breeds. Ex-
cellent types of beef cattle and of merinolike sheep are to be seen in
some of these ancient relics, which mark the beginnings of recorded
history. Jacob's famous agreement with Laban regarding "goats
that were ringstraked and spotted" (Genesis 30: 35) has often been
cited as evidence of an early belief in maternal impressions. But we
read in. the next verse that Jacob relied on "three days' journey"
between Laban's solid-colored "cattle" and his own spotted flocks,
and when it is explicitly stated that the rams used were spotted, it
is clear that this ancient Hebrew herdsman did not depend entirely
CHRONOLOGY 1459
on magic to produce results in animal breeding. Early Hindu
writers also discussed these matters at length.
Wlule the philosophers and scholars of the Middle Ages were piling
one improbability on another, at least two great modern breeds were
being formed — the Arab horse and the merino sheep. The desert
horse had very remote beginnings, and it had reached or maintained
such a state of excellence by the Middle Ages that it contributed
greatly to the development of the horse of today. The English
Thoroughbred breed traces to two Arab horses and a Barb imported
into England about the time of Charles II. From very remote begin-
nings the Spanish merino had reached a perfection that gave Spain
virtually a monopoly of the fine wool weaving industry by the fifteenth
century. Tliis monopoly was maintained by a strict embargo.
Through royal courtesy the ban was lifted in 1705 to permit the ex-
port of merinos into Saxony. Within a few years merinos were ex-
ported from Spain to several other countries. In 1786 the famous
merino herd at Rambouillet, France, was established. Maintained
continuously since that time with only one importation of outside
blood, this herd has formed the basis for the modern Rambouillet
breed, which today is spread over all the world and is raised in greater
numbers than any other type of sheep.
One other "root" of modern genetics also had a very early begin-
ning. Mathematics was a subject intensively studied in Babylon,
Egypt, and Greece. Some branches of the science of numbers were
highly developed among the ancients, although algebra, so essential
in modern genetic experiments, was not well developed until after
the Crusades. This early science of numbers formed the groundwork
for the later development of statistics, probability, and correlation,
all necessary tools of modern genetics.
BACKGROUND
By the beginning of the seventeenth century a new spirit of scien-
tific skepticism had begun to be manifest. The reaction of common
sense against the cumulative absurdities of centuries of uncontrolled
verbalism was reflected in the first stirrings of an age of scientific
experiment. Nehemiah Grew in 1676 suggested the nature of ovules
and pollen. A growing interest in biology culminated in the publi-
cation in 1694 of Camerarius' (Germany) famous 50-page letter on
the sex of plants (De Sexu Plantarum Epistola), which put on record
convincing evidence that plants are sexual organisms. This was
followed early iu the eighteenth century by the production of the first
artificial plant hybrid by Thomas Fairchild (in England a short time
before 1717). The practical implication of these discoveries is re-
flected in the founding in 1727 of the seed-breeding establishment
today world-famous as Vilmorin-Andrieux et Cie. (One of the early
great successes of the Vilmorins was the development of the sugar
beet during the Napoleonic era.) In the next 50 years there was a
veritable wave of hybridizing. Crosses between more than a dozen
different plant genera were made by several investigators and reported
with varying degrees of accuracy. This period culminated in the
publication of J. G. Koelrcuter's work (Germany, 1761-66), report-
ing the results of 136 experiments in artificial hybridization. This
1460 YEARBOOK, 1937
mass of evidence definitely established plant hybridization as a scien-
tific pursuit.
At the same time independent progress was being made in fields that
after 1900 were to have a profound influence on genetics. M. Mal-
phigi (Italy) was laying the groundwork for descriptive embryology
(1650-70). A. von Leeuwenhoek (Holland) was discovering the tiny
world of the miscroscope, and with his pupil, Johau Ham (Holland),
in 1677, was the first to see mammalian germ cells (spermatozoa).
In 1780 L. Spallanzani (Italy) attempted to demonstrate by artificial
insemination in dogs the essential part played by the male in fertiliza-
tion.1 The modern science of statistics had its beginnings at about
the same time, in a treatise published in 1761 by a Prussian divine,
J. P. Siissmilch, who undertook by appeal to vital statistics to prove
the glory of God. The leisurely progress of scientific thought is sug-
gested by the award to Linneaus (Sweden) in 1 760 of a prize for an
essay on sex in plants: — nearby a century after Camerarius had rather
conclusively laid the groundwork of this subject. Linnaeus' publi-
cation of Species Plantarum in 1753, which attempted to classify
plants according to their assumed relationships, marks an important
step in the development of evolution theory. In 1760 Robert Bake-
well. (England) took over the management of the Dishley Estate,
where for 35 years he proved to his own satisfaction that inbreeding
is not necessarily injurious and that it is the quickest way to fix type.
His experiments laid the groundwork for the development of many
of the modern breeds of livestock. In 1793 C. K. Sprengel (Prussia)
observed the cross-pollination of plants by insects.
In the matter of human heredity some knowledge had also been
accumulating. From the earliest times resemblance in relatives had
been noted . The inheritance of such definite anatomical peculiarities
as the "Hapsburg jaw" had frequently been recognized. Man has
never been well adapted for laboratory study, and little exact progress
was made. A notable exception has to do with sex-linked inheritance.
The peculiar inheritance of color-blindness was reported to the
Royal Society as long ago as 1779 by a British divine, Michael Lort.
Forty years later C. T. Nasse (Germany) formulated a law of sex-
linked inheritance based on hemophilia, a disease of unusual interest
because of its occurence in the royal families of Europe.
By 1760 the stage was set for a century of biological progress that
culminated in 1859 with the publication of Darwin's Origin of Species.
GENETICS IS BORN, 1760-1900
1760-1830 — Foundation of important livestock breeds through inbreeding and
selection practiced by English breeders — Bakewell, Bates, the Collings,
and others.
1809 — Publication of J. B. P. de Lamarck's Philosophic Zoologique (France)
represented the first attempt to produce a comprehensive theory of evo-
lution. Erasmus Darwin (England), G. L. L. de Buffon (France), and
W. von Goethe (the German poet whose Metamorphosis of Plants, 1790,
is a notable milestone in biological thinking) had dealt with various phases
of the problem of organic development of individuals, species, and genera.
Lamarck attempted to weld these observations and speculations into a
coherent theory of evolution, an important step in biological progress.
1 His "proof" that the fluid and not the spermatozoa was the fertilizing agent was unfortunately wrong.
Not until 1824 did Pxevost and Dumas correct this mistake.
CHRONOLOGY 1461
1812 — (1) Karl Friedrich Gauss (Germany), Theoria combinations observa-
tioimm erroribus minimis obnoxia (theory of least squares — basic in the
statistical evaluation of data) .
(2) Pierre Simon Laplace (France), Theoric analytiques des proba-
bilitcs. Beginning of "the law of error concept."
1820 — (1) Gauss, evolution of the probable error- — for a century the almost
universally used test of the significance of experimental data"
(2) C. F. Nassc (Germany) , Nasse's law of male sex-linked inheritance,
based on study of hemophilia.
1822 — John Goss (England) reports but does not interpret dominance and reces-
siveness, and segregation in pea hybrids.
1823 — Thomas Andrew Knight (England), Knight-Darwin law of cross-breeding
(value of crossing to produce better plants). Dominance, recessiveness,
and segregation observed in peas without mathematical relationships.
1826 — A. Sageret (France) classifies contrasting characters in the parents of a
cross in pairs, using muskmelons and cantaloups, cites unit characters in
human eye color, and uses the term "dominant."
1835 — (1) Division of cells described by H. von Mohl (Germany).
(2) Publication of K. F. von Gaertner's Memoir (Germany) reporting 25
years of hybridization experiments dealing with 107 species of plants;
noted distinction between the uniformity of first hybrid generation and
the diversity of later generations, and reported hybrid vigor.
1838-39 — Cell theory, M. J. Schleiden and T. Schwann (Germany). First
generalized statement of the theory that all organisms are made up of
cells — one of the great generalizations of experimental biology.
1840 — Word "protoplasm" coined by J. E. Purkinje (Bohemia), though used in a
slightly different sense from that of today. A. Payen (France) and F.
Cohn (Germany) suggested the essential similarity of protoplasm as the
physical basis of all life (1846-50).
1841 — R. A. von Kollikcr (Switzerland) proves that spermatozoa arise from
parent body and are not parasites as was previously believed.
1840-50 — Louis de Vilmorin (France) develops the progeny test ("genealogical
selection") in wheat, oat, and sugar-beet breeding.
1843 — John Le Couteur (island of Jersey) publishes a summary of his work on
wheat breeding. "This summary has been the basis and origin of variety
testing" (De Vrics). The same methods wore independently developed
somewhat earlier by Patrick Sheriff (Scotland), who produced many out-
standing varieties.
1846 — (1) A. Quetelet (Belgium), Lettros . . . sur la Theorie des Probability.
Described biological phenomena in quantitative terms.
(2)Von Mohl recognizes nature and importance of protoplasm in its
present sense.
1848 — W. Hofmeistcr (Germany) figures the chromosomes as unstained bodies,
but without appreciating their significance.
1849 — (1) Sir Richard Owen (England) enunciates principle of the continuity
of the germ plasm. This idea was developed by Virchow, Weismann,
and others, and culminated in the modern gene theory.
(2) Union of sperm cell and egg cell (fertilization) first seen in seaweed
(Fucus) by G. Thuret (France). A year later he showed that the egg
would not develop without fertilization.
1858 — R. Virchow (Germany) enunciates the principle: Omnis cellula e
cellula (every cell from a cell), finally disposing of the theory of
spontaneous generation — a basic biological generalization which com-
pleted the cell theory, establishing the continuity of all life from remote
beginnings.
1859 — Publication of Charles Darwin's Origin of Species (England). This
contains extensive discussions of hybrids, but its contribution to gen-
etics was mostly indirect. It marks a turning point in scientific thought
and dates the beginning of the modern experimental approach to biological
problems.
1861-62 — M. J. S. Schultze (Germany) and H. A. de Bary (Germany) establish
the essential unity of protoplasm in all living cells.
1462 YEARBOOK, 1937
1863 — D. A. Godron and C. V. Naudin (Prance) independently report experiments
in plant hybridization. Naudiu confirmed Sageret's work, in general dis-
cussed work of the early hybridizers, and reported dominance and segrega-
tion in Datura (jimsonweed) hybrids. He did not deal with single char-
acters and reported no statistical observations on the second generation.
His theoretical explanation of his facts was a forerunner of Mendel's ideas,
but inferred rather than deduced.
1865 — F. Schweigger-Seidel and A. von la Valette St. George (Germany) inde-
pendently prove that a spermatozoon is a single cell and contains nucleus
and cytoplasm.
It is impossible to tell how much of this earlier work was known
to Gregor Mendel. Very likely most of it was. The work of Godron
and Naudin was jointly awarded a prize by the French Academy of
Sciences, so that it must have been fairly well known in scientific
circles. Mendel had access to a rather extensive library, which
included all of Darwin's works, and many other books on plant
hybridization, etc. He was in contact with such eminent biologists
as Nageli, so that there is an excellent possibility that he had the
benefit of this earlier work. But be that as it may:
1866 — (1) Gregor Mendel (Austria) publishes in the Proceedings of the Brimn
Natural History Society (Verhandlungeu der Natur Forschenden Verein
in Brunn) his investigations concerning plant hybrids, Versuche tiber
Pflanzcn-Hybriden, one of the oustandingly lucid and detailed expositions
of a fundamental discovery. For 34 years Mendel's papers lay forgotten.
(2) E. Haeckel (Germany) predicts that the cell nucleus will play a star
role in heredity.
1867 — (1) Vilmoiin tests immediate effect of pollen.
(2) H. S. Bidwell (United States) reports controlled pollination in maize.
1868— Darwin's pangen hypothesis — gemmules (hypothetical particles that float
in the blood stream) are given off by cells and held to modify germ cells.
1873-4 — L. Auerbach (Germany) begins experimental study of cell mechanics
(fertilization) .
1875 — (1) E. Strasburger (Germany) describes the chromosomes.
(2) Oscar Ilertwig (Germany) proves that fertilization consists of union
of two parental nuclei contained in the sperm and ovum. This demonstra-
tion that sexual reproduction is a process contributed to essentially equally
by the two sexes marked an important advance. It disposed of speculation
regarding the role of the two sexes in inheritance, and it showed that
genetics is basically a problem of cell physiology.
1878-81 — W. J. Beal (United States) determines increased yields of corn hybrids
between varieties and suggests their use in corn production.
1879-82 — W. Flemming (Germany) describes the longitudinal splitting of the
chromosomes.
1881 — W. O. Focke (Germany) coins the term "xenia" to denote immediate effect
of pollen on the endosperm in the maize seed.
1883 — (1) P. J. van Beneden (Belgium) begins study of early history of animal
egg. Reports reduction of the chromosome number in the egg cells to half
that in body cells and holds that chromosomes have a genetic continuity
throughout the life cycle — basically important concepts in genetic theory.
(2) E. L. Sturtevant (United States) observes without interpreting first
linkage of genes now known as tunicate and sugary (TuSu) in maize.
1884 — K. W. von Nageli (Switzerland), ideoplasm concept — control of heredity-
seen as due to "ids", which were conceived to be solid particles. Nageli's
book was important as a precursor of Weismann's The Germ Plasm.
1884-5— (1) Identification of the cell nucleus as the basis of inheritance "made
independently and almost simultaneously by Hertwig, Strasburger,
Kolliker, and A. Weismann" (Germany) .
(2) Halves of split chromosomes shown going to opposite poles by
Flemming and others.
1885 — C. Rabl (Austria) announces the individuality of the chromosomes.
CHRONOLOGY 1463
1886 — (I) Francis Galton (England) devises the correlation table — a most useful
tool in applying statistical methods to many biological problems.
(2) Hugo de Vries (Holland) discovers aberrant evening primrose plants
at Hilversum, Holland. Experiments with these extending over 15 years
■formed the basis for his mutation theory of evolution.
1885-87 — Weismann publishes a theory of chromosome behavior during cell
division and fertilization which explains earlier observations of Van Bene-
den, Strasburger, etc., and predicts that two kinds of cell division will be
discovered — mitosis (already known) and reduction, in which the chromo-
some number will be reduced to half by an orderly separation of paternal
and maternal chromosomes.
1887 — W. Roux (Germany) suggests that the longitudinal splitting of the chro-
mosomes when dividing means that many different qualities are arranged
single file in the chromosome, and that these are all contributed by this
method of division to each daughter cell.
1887-88 — Th. Boveri (Germany) verifies Weismann's prediction of the reduction
of the chromosomes by observing the phenomenon in Ascaris.
1888 — Chromosomes named by W. Waldeyer (Germany).
1889 — (1) De Vries revises the "pangen" theory of determiners floating in the
blood stream, and denies any transfer of gemmules (determiners) from
body cells to gametes.
(2) Francis Galton (England) publishes Natural Inheritance, which
formulates his law of ancestral inheritance — a statistical statement of the
relative influence of parents, grandparents, etc., in determining charac-
teristics in offspring.
1890 — (1) Law of numerical equality of paternal and maternal chromosomes at
fertilization in animals and plants (Boveri, Germany; L. Guignard,
France) .
(2) Babcock test for buttcrfat percentages (United States). Begin-
nings of dairy-cattle selection for buttcrfat production oil scientific basis.
1891 — (1) Willctt M. Hays (United States) develops the centgener progeny test,
thereby recognizing that the test of the genetic quality of an individual
can be adequately evaluated only by a study of its progeny. At about the
same time the New York (Cornell) Agricultural Experiment Station
develops rod-row method of small grain testing.
(2) W. A. Kellerman and W. T. Swingle (United States) make first
count on a segregating ear of maize.
1892 — With publication of Das Keimplasma (The Germ Plasm) Weismann
enunciates the then very radical principle of noninhcritance of acquired
characters, and expands Nageli's idioplasm theory to bring cell theory
and "genetic theory" into organic relationship. Basing his theory on
Van Beneden's observations. Weismann explains the reduction division
as a method of exactly distributing the chromosome material.
1894 — (1) W. Bateson (England) emphasizes the importance of the study of
"discontinuous variation" (an approach toward the idea of Mendclian
units) in solving the problem of heredity.
(2) Karl Pearson (England) publishes first of Contributions to the
Mathematical Theory of Evolution, developing methods of dealing statis-
tically with skew frequency curves.
(3) A. Millardct (France) notes "false hybrids" entirely resembling
pollen parent (patrogenesis) .
1897 — (1) G. Udny Yule (England), publications On the Theory of Correla-
tion.
(2) First egg-laying contests (England).
1898 — (1) Pearson develops Galton's Law of Ancestral Heredity and also intro-
duces the standard deviation, an improved method of determining the
significance of deviations of observed data from theoretical perfection.
(2) S. G. Navashin (Russia) discovers double fertilization in higher
plants.
(3) W. J. Spillman (United States) notes segregation in wheat, which he
reported in 1901 in an independent statement of Mcndelian principles.
(4) G. M. Gowell (United States) installs 52 trap nests and initiates
scientific breeding for egg production.
(5) Flemming counts human chromosomes, finding 24 in corneal (eye)
tissue. (Later work with improved technique shows 24 pairs.)
1464 YEARBOOK, 1937
1899 — (1) L. Cucnot (France) working with animals, and Strasburger (Germany)
working with plants, advance theory that sex is controlled within the
germ cell, not by environment.
(2) De Vries and C. F. J. E. Correns (Germany) publish almost simul-
taneously an explanation of xenia in corn as due to double fertilization.
(3) First International Conference of Hybridization (the later con-
ferences in this series were called Congresses of Genetics) held in London.
EARLY DAYS OF GENETICS
The turn of the century was an epochal year in the experimental
study of heredity. The almost simultaneous rediscovery of Mendel's
paper independently by three investigators (who had, when they read
Mendel's paper, experimental material of their own to verify his
conclusions), was a striking symptom of an even wider trend. Bateson
had for years been attacking the problem of discontinuous variation,
and Haldane says that had not Mendel's paper been discovered,
Bateson would undoubtedly have been buried in Westminster Abbey
as the discoverer of atomic heredity. Spillman's wheat work in the
United States had reached a point where he appears to have been just
on the brink of making the same illuminating generalization. Other
workers also were hot on the trail of the gene, and the time was ripe
for a veritable explosion of genetic progress. Within 3 years of the
triple De Vries-Correns-Von Tschermak announcements, abundant
verification of Mendel's work had been made by many workers, and
the universality of the Mondelian principles had been demonstrated
in plants, animals, and man. The fecund pomace fly, Drosophila,
was about to enter his milk-bottle kingdom and populate acres of
banana-agar nutrient medium with an ever-growing progeny of
mutant forms. Into the hands of the research investigator had been
given the key to unlock that perennial mystery of the ages, heredity.
1900 — Rediscovery and verification of Mendel's principles independently by
De Vries (Holland), Correns (Germany), andE. von Tschermak (Austria),
marking the beginning of modern genetics.
1901 — (1) H. Henking (Germany), F. C. Paulmier (United States), and others
report an "accessory chromosome" in spermatozoa (later identified with sex
determination), based on work begun in 1891.
(2) Bateson publishes a translation of Mendel's paper.
1902 — (1) Terms allelomorph, homozygote, hetcrozygotc, Fi, F2, coined by Bate-
son. Iu their report to the evolution committee, Bateson and Saunders
list 26 instances of allelomorphism which had been "actually provedt to
exist, or may be inferred from the published record." This included cases
in peas, wheat, maize, Datura, Oenothera, snapdragon, mouse, fowl, catle.
The Mondelian nature of polydactylism (an extra finger) in man was
suggested.
(2) De Vries — The Mutation Theory of Evolution, based on studies of
evening primrose.
(3) T. TI. Montgomery (United States) announces the pairing of homolo-
gous maternal and paternal chromosomes during synapsis (joining and
separation prior to formation of germ cells with reduced chromosome
number).
(4) E. C. McClung (United States) relates an accessory chromosome
found in some insects to sex determination — first attempt to connect a
specific character with a particular chromosome. The concept of specific
sex chromosomes, which have a major influence in determining sex, has been
verified, with modifications, in a range of organisms extending from the
pomace fly to man.
(5) Cuenot first demonstrates Mendelism in animals (normal and albino
mice) .
CHRONOLOG Y 1465
1902 — (6) Bateson defends Mendelism against attacks of W. P. R. Weldon and
Karl Pearson (England). This heated clash regarding the utility of experi-
mental versus statistical approaches to biological problems continued inter-
mittently until 1904. Publication of first number of Biometrika, the load-
ing journal dealing with the statistical aspects of genetics.
1902-3 — Yv. W. Sutton (United States) shows that body chromosomes are indi-
vidually recognizable and points out the mutual interrelations between
cytological observations and Mendclian phenomena, closing the gap be-
tween cytology and genetics.
1903 — (1) Pure-line concept (variations in the progeny of a single plant of a self-
fertilized species are not due to inheritance) first put forward by W. L.
Johannscn (Denmark). Plienotype and genotype defined. Modern con-
cept of "selection" born.
(2) R. H. Biffen (England) reports that resistance to stripe rust of wheat
is governed by a single Mendelian recessive factor.
(3) Bateson (walnut, rose, and single comb in fowl) and Cucnot (albino
and pigmented mice) note interaction of nonallelomorphic factors (later
called epistacy).
1904 — (1) C. B. Davenport (United States) confirms Mendelian inheritance of
polydactylism in man.
(2) American Breeders Association founded under Secretary of Agricul-
ture James Wilson, with Willett M. Hays as secretary.
(3) Thomas Hunt Morgan becomes professor of zoology at Columbia
University. This represents the beginning of the former "Columbia
group" of genetic research workers, which included many of the names
outstanding in genetics today. Other centers also had their origin about
this time, at Harvard University, the University of Chicago, the Univer-
sity of Indiana, and Leland Stanford University.
(4) Station for Experimental Evolution established by the Carnegie
Institution of Washington.
(5) A. F. Blakeslee (United States) reports isolation of sex-different
strains of molds. First called "plus" and "minus", these were later called
"male" and "female" though no morphological differences could be found
between them.
1905 — (1) G. H. Shull and E. M. East (United States) begin independent experi-
ments on inbreeding in maize that opens up a field of the utmost theo-
retical and practical importance.
(2) N. M. Stevens and E. B. Wilson (United States) confirm McClung's
sex-determination theory.
(3) "Coupling" (linkage) in sweet pea analyzed by Bateson, E. R.
Saunders, and R. C Punnett (England). Bateson and Punnett explain the
walnut comb in the fowl as being due to two dominant factors, one of which
alone produces pea combs, and the other, rose combs — the double recessive
being single combs. This first report of interaction of Mendelian factors
marked a very important advance.
(4) O. F. Cook and W. T. Swingle (United States) publish diagram and
propose names for the sexual cycle (sporophyte-gametophyto) in plants.
1906— (1) Term "genetics" coined by Bateson.
(2) C. W. Woodworth and W. E. Castle (United States) "discover"
Drosophila. "More has been learned concerning heredity from this one
species since 1910 than had been learned from all sources before that
time." It produces 25 generations a year and has but 4 pairs of chromo-
somes, so that it is ideally suited to make linkage studies. The modern
gene theory is based largely on studies of Drosophila.
(3) Possible relation between linkage and the chromosomes pointed out
by R. H. Lock (England).
(4) George Rommel begins U. S. Department of Agriculture inbreeding
experiments with guinea pigs, which have been continued ever since.
1907 — (1) Correns advances theory of two kinds of male gametes (male-determin-
ing and female-determining).
(2) J. B. Norton (United States) publishes rod-row system of breeding,
first put into general use by him in 1902.
(3) Strasburgor uses terms haploid and diploid for reduced and double
number of chromosomes.
138004 °— :J7 1)3 ++
1466 YEARBOOK, 1937
1907 — (4) A. M. Lutz (United States) .shows that the gigas mutation of the
evening-primrose has double number of chromosomes of Oenothera
lamarckiana Ser.
The discovery of a tetraploid in the evening-primrose opened up
the subject of variation of chromosome number in general, and of
polyploidy in particular. This discovery that organisms might vary
in their chromosome constitution by an entire set of chromosomes has
today developed a xery extensive branch of cyto-genetics. Discover-
ies of polyploid series in wheat, the roses, the Daturas and Solanums,
and elsewhere have marked a distinct advance in our understanding
of the development of species. The artificial production of polyploids
by heat treatment and by other means has been a more recent devel-
opment of great promise. Even greater in its possibilities may be the
production of generic polyploids (amphidiploids) having one or more
complete chromosome complements from each parent species. These
forms are generally self-fertile but are usually sterile with the parent
species or genera.
(5) Bateson coins terms "cpistatic" and "hypostatic" to describe inter-
relations of non-allelomorphic genes.
1908 — (1) Cuenot discovers that the yellow gene ( Y) in mice is lethal, suggesting
that it kills the embryo early in development when inherited from both
parents.
(2) Zeitschrift fur induktive Abstammungs-und Vcrerbungslehre
(Journal for Inductive Descendence and Inheritance Theory) founded.
(3) Delaware Agricultural Experiment Station begins inbreeding
experiments with swine.
Many practical breeders before this time had used intensive inbreed-
ing in their operations, but the degree of inbreeding actually practiced
is very hard to determine. Several instances are on record of herds
being maintained for a number of generations without the introduction
of new blood. N. H. Gentry's work with Berkshire swine in Missouri
was a notably successful example of the use of inbreeding in breed
improvement. The Delaware experiment represents the first attempt
to attack this problem in a scientific manner with farm animals. All
of the swine inbreeding experiments (and they are practically the only
experiments in the intense inbreeding of livestock, by brother X sister
matings, that have been undertaken, though considerably more has
been done with poultry) have been only partially successful from a
practical standpoint. The hoped-for production of highly inbred lines
of swine that could be crossed to utilize to the full the principle of
hybrid vigor in the first generation has failed to materialize because
of the practical difficulties encountered in maintaining the inbred lines.
Theoretically there appears to be no reason why robust inbred lines
cannot be produced as has been done with rats and guinea pigs.
Among the outstanding later experiments are those at the University
of California, the Oklahoma Agricultural Experiment Station, Iowa
State College (poultry), the Minnesota Agricultural Experiment
Station, and the United States Department of Agriculture.
Many less direct attempts to produce highly inbred herds of live-
stock have been started and are continuing. Notable among these
is the United States Department of Agriculture's development in
dairy-cattle breeding, which has continued since 1912. The intention
is to produce dairy sires pure or homozygous for high production by
CHRONOLOGY 1167
line breeding as intense as possible to the foundation sire of the herd.
While many practical breeders have used this method with livestock
for short periods, this continuing project, with accurate records for
many generations, is unique.
(4) H. Nilsson-Ehle (Sweden) explains that inheritance of color of seed
in wheat is largely due to three Mendelian factors — multiple factors and
blending inheritance begin to be added to Mendelian concepts. This
principle was confirmed a year later by East in corn.
1909 — (1) Crossing-over hypothesis (exchange of segments in paired chromosomes)
advanced by F. A. Janssens (Belgium).
(2) R. A. Emerson (United States) reports multiple allelomorphs (more
than one alternative factor) in beans and maize.
(3) Sir Francis Galton's bequest to found the Galton Laboratory at the
University of London establishes the first laboratory devoted to the study
of human heredity.
(4) Shull suggests use of first-generation hybrids between inbred lines
as a basis of practical corn breeding.
1910 — (1) L. Epstein and R. Ottenberg (United States) point out that human
blood groups (discovered by K. Landsteincr, Austria, in 1900 and classified
by Jansky, Germany, in 1907) follow Mendelian principles in inheritance.
(2) Morgan proposes explanation of sex-linked inheritance; publishes
first gene mutation in Drosophila (white eye) .
(3) Announcement of the gene theory by Morgan, which includes the
principle of linkage of genes resident on the same chromosome. This
brilliant hypothesis has been upheld in a multitude of experiments. Bo-
ginning of chromosome maps compiled by linkage and cross-over data.
(4) A. B. Bruce, and F. W. Keeble, and C. Pellew (England) suggest that
hybrid vigor is due to dominant favorable growth factors.
v (5) A. Lang (Switzerland) suggests multiple factor hypothesis to account
for size differences in rabbits.
(6) H. Winkler (Germany) publishes method of producing Solarium
chimaeras artificially. The" explanation of these chimaeras as layers
(periclinal) and sectors (sectorial) of cells from stock and cion was fur-
nished by Erwin Baur (Germany) 1914.
1911 — (1) Journal of Genetics (England) established.
(2) Raymond Pearl (United States) publishes the first of his studies of
egg production in the fowl.
(3) G. N. Collins and J. H. Kempton (United States) report first link-
age in maize.
(4) Baur publishes the first edition of his Introduction to the Experi-
mental Study of Heredity, Einfuhrung in die experimentelle Vererbungs-
lehre.
(5) Richard Goldschmidt (Germany) publishes the first edition of his
Einfuhrung in die Vererbungswissenschaft (Introduction to the Science
of Heredity), which summarizes his theory of sex determination as a
matter of rate of developmental expression of sex-determining genes —
demonstrated by the production of intersexual forms in hybrids of the
gypsy moth.
(6)" W. E. Castle and J. C. Philips (United States), ovary transplanta-
tion experiment in the guinea pig, showing nonmodifi cation of genetic
characters through change in embryo environment.
(7) Cuenot, explanation of multiple allelomorphism in mice.
1912 — (1) R. R. Gates (England) identifies Oenothera semi-gigas Vries as a trip-
loid — the first to be recognized (triploids have three sets of chromosomes) .
(2) H. S. Jennings (United States) shows that with self-fertilization the
percentage of heterozygosis is halved in each successive generation.
This principle was elaborated by H. D. Fish (United States 1914)
and Pearl 1913-17, and expanded by Jennings in 1917. In 1923 Sewell
Wright (United States) published a general inbreeding coefficient
applicable to irregular systems of mating. Since that time the
evolutionary implications of Mendelian heredity have been developed
by Wright, R. A. Fisher, J. B. S. Haldane, and others.
1468 YEARBOOK, 1937
1913 — (1) C. B. Bridges (United States) reports nondisjunction of sex chromo-
somes (both sex chromosomes going to one gamete and none to the other).
Important confirmation of chromosome theory.
(2) Nils Hansson (Sweden) publishes first formula for a sire index, an
improvement in the progeny test for characters not expressed by the sire.
More recently the sire-index idea has been elaborated by a number
of suggested modifications of Hansson's original idea. All of these
are based on the concept that the sire's transmitting ability for a
character he does not himself show (such as milk or egg production)
can be measured by comparing the production of his daughters with
that of their dams. This concept is one of the bases of the "proved-
sire movement" started in 1918 by the United States Department of
Agriculture, which attempts to discover and to utilize to the maximum
the sires that transmit desirable qualities to the greatest degree.
1915 — Morgan, A. H. Sturtevant, Bridges, and H. J. Muller (United States)
publish The Mechanism of Mendelian Heredity — an epoch-making book.
1916 — (1) Castle confirms Lang's multiple-factor hypothesis of blending inherit-
ance in rabbits.
(2) Winkler produces polyploid forms from the callus tissue of decapi-
tated grafts.
This method of doubling, tripling, and quadrupling the chromosome
number has been rather widely used in experimental procedures by
other workers. By applying it to haploid tomatoes, E. W. Lind-
strom (United States, 1927) was able to obtain a pure line by doubling
of identical chromosome complements — a procedure of considerable
value in genetics and plant breeding.
(3) Castle and Wright discover first linkage in a mammal (rat).
(4) Pearl demonstrates effectiveness of pedigree selection contrasted
with mass selection in the fowl.
(5) Shull suggests the word "heterosis" to designate the vigor of first-
generation hybrids.
1917 — (1) O. Winge (Denmark) elaborates theory of polyploid origin of new
species by multiplication of a basic chromosome complex.
(2) Emerson finds variegated pericarp in maize due to an unstable gene.
(3) The Connecticut Agricultural Experiment Station produces the first
commercial "crossed corn."
Following the early experiments of Beal, and the inbreeding experi-
ments of Shull and East, inbreeding experiments with maize enjoyed
a considerable vogue. It was found that where some of these uniform
but usually rather unpromising inbred lines were crossed, an extremely
vigorous and uniform first-generation hybrid was produced, which
exceeded the yields of commercial varieties by 30 percent or even
more. The production of this crossed corn seed on a commercial
basis was first attempted at the Connecticut Station. Unfortunately
the lack of vigor and the small quantities of seed produced by the
inbred strains made seed production difficult and expensive. To
obviate this difficulty the system of "double-crossed corn" (suggested
by D. F. Jones in 1919, first commercial production attempted in
1921 by George S. Carter, Clinton, Conn.) was perfected, whereby
four inbred lines were used. These lines (designated A, B, C, D)
are crossed in pairs (A X B and C X D), and the resulting two extremely
vigorous hybrids are crossed to produce the commercial seed. These
varieties have great vigor and uniformity,' and production of seed in
commercial quantities is entirely feasible. Many workers have con-
CHRONOLOGY 1169
tributed notably to this development, ninong them D. F. Jones, H. A.
Wallace, F. D. Bichey, and M. T. Jenkins, and many others in the
United States Department of Agriculture and in the Corn Belt
experiment stations.
The concepts developed by inbreeding have been applied in other
ways, such as that of shifting a single desirable character from one
variety to another by crossing and then by repeatedly back-crossing,
to the other parental variety with the majority of desirable charac-
teristics, those segregates that have the one desired character. II. V.
Harlan and M. L. Martini (United States) first used this technique
in barley in 1922, and it has been applied with equal success by several
other workers.
(4) W. B. Kirkham, II. L. Ibsen, and E. Stoigledor (United States)
prove the lethal action of the yellow gene in the mouse by embryological
studies.
The attempt to trace the beginnings of gene elfects in the earliest
possible stages of development (and to follow through to maturity
the developmental history of a gene) has grown iuto a new and
promising but often very difficult branch of genetic research — the
"genetics and development" studies. The problem has also been
approached by experiments in the transplantation of tissues and
organs, by hormone injections, and by studies of the gene chemistry
involved in color development of hair, etc. The field is just
beginning to be explored.
(5) J. Jcswiet (Netherlands) working in Java proves that the Kassoer
sugarcane (used in breeding mosaic-resistant P. O. J. hybrid sugarcane) is
a second-generation hybrid of true sugarcane with a wild grass, Saccharum
spontaneum L., that contains little or no sugar. This initiated large-scale
sugarcane breeding in many countries, with wild relatives used to secure
disease resistance. Later researches showed that the vigorous, disease-
resistant, high-yielding sugarcane hybrids all showed a much higher
chromosome count than true sugarcane (polyploidy).
1918 — H. D. King (United States) reports results of inbreeding rats for 25 con-
secutive generations, showing that close inbreeding is not necessarily dele-
terious, and that fertility and vigor can be maintained in some lines.
1919 — Morgan and others publish The Physical Basis of Heredity, setting forth
in detail the gene theory, and summarizing Drosophila genetics.
RECENT DEVELOPMENTS
Even from the safe vantage of a third of a century it is not easy to
evaluate the developments that followed the rediscovery of Mendel's
work. As we advance nearer to the present our task becomes more
difficult, for discoveries that now seem not especially revolutionary
may, in the light of later work, be as epochal as Mendel's pioneer con-
tribution. The time is too short to place a final value on many
advances, and progress is being made on too many fronts to attempt
to cover adequately the multitudinous work in genetics and related
sciences. Some recent developments that may have been overlooked
may be much more important 20 years hence than they seem today.
Thus the compiler is sure only that in this most hazardous part of his
journey he is treading on very dangerous ground indeed.
It was planned in compiling this chronology to avoid mention of
any names in this final part, simply citing significant developments
and trends, letting the perspective of tho years determine more fairly
1470 YEARBOOK, 1937
those who have made fundamental contributions to genetic progress.
In practice this has proved difficult, because some names are so closely
linked to certain discoveries that anonymity seems unfair. Thus
radiation genetics and salivary-gland chromosomes immediately bring
to mind the names of the pioneers whose work has very recently led
the way to new bonanzas of genetic facts. Certain developments
have been so interesting and significant that to stop the chronology
10 or 15 years ago purely through the promptings of the instinct of
self-preservation would destroy much of its interest and value. The
following compromise, which attempts to maintain perspective at
very short range, is put forth with many misgivings and with a pain-
ful realization of the hazards involved. In the short summary para-
graphs frequently interspersed with names and dates, an attempt has
been made to suggest the extent and significance of some of the impor-
tant developments.
1920 — (1) Tobacco variety "made to order" by genetic methods (East and Jones
in the United States) .
(2) H. D. Goodale's (United States) studies of effects of selection on
egg production.
(3) E. B. Babcock (United States) begins Crepis investigations, which
are adding much to our knowledge of chromosome evolution within a genus.
(4) G. Tackholm (Sweden), monograph on polyploid series in Rosa,
suggesting how a genus may have evolved through changes in chromosome
number.
1921— (1) Triploid discovered in Drosophila by Bridges.
(2) Morgan estimates that the gene has a diameter between 20 and 70
microns.
Since Morgan first attempted to estimate the size of the gene several
other approximations have been attempted. These have been based
on the volume of the chromosomes, the number of genes known to
to reside in the chromosomes, and the number of mutations that have
been known to occur in a given chromosome; or on the number of
mutations alone. As our knowledge of the number of genes increases,
the maximum estimated size of the individual gene is necessarily
reduced. Very recently the problem of gene action has begun to be
attacked from the angle of the physical chemist by D. Wrinch (Eng-
land) and other biochemists. It is thus shown that the giant protein
molecules of which the chemists have built mental pictures through
X-ray analysis and by other means come within the range of size
postulated for the individual gene. At the present time no experi-
mental evidence exists to prove the speculations that the gene in fact
consists of a single molecule.
(3) East makes genetic analysis of partial sterility in tobacco hybrids.
1922 — (1) Haploid Datura discovered by A. F. Blakeslee, J. Belling, M. E. Farn-
ham, and A. D. Bergner (United States). This is the first discovery of
a flowering plant developing with single instead of paired chromosomes.
(2) R. E. Cleland (United States) shows that characteristic arrangement
of chromosome chains (rings) in Oenothera are typical of different species.
1923 — (1) K. Sax (United States) demonstrates linkage between quantitative and
qualitative characters in the garden bean.
(2) F. A. E. Crew (Great Britain) presents evidence to show that the
"bulldog" calf, a nonliving monster frequently appearing in crosses of
Dexter and Kerry cattle, is due to a lethal factor.
While other workers had suggested the inheritable nature of this
defect, Crew was the first worker to suggest the possibility of its being
CHRONOLOGY 1171
a lethal Mendelian character, the first lethal character identified as
such in the livestock breeds. Since that time many other lethals
have been recorded. O. Wriedt (Norway) has noted a tendency
for outstanding dairy sires to transmit lethal factors, suggesting a
linkage between such lethals and factors of economic value. They
are thus a matter of some importance to the practical breeder. Their
genetic interest is considerable because of the studies they have made
possible in the developmental history of genes, from fertilization to
adult organisms — the first of these being the study of L. C. Dunn
and W. Landauer (United States) on the "creeper" fowl.
1924 — (1) Blakeslee and Belling produce pure-lino Datura by self-fertilization of
a haploid.
(2) W. R. Taylor adapts smear technique to plant cytology, simplifying
previous cumbersome methods and making possible tlio study of a much
larger amount of material.
(3) Blakeslee, Belling, and Farnhani explain certain Datura mutants as
being plants with an extra chromosome. Blakeslee suggests the term
"simple trisomic" for such forms in a classification of chromosomal types.
(4) W. T. Swingle and It. W. Nixon (United States) coin the term
"metaxenia" to describe the effect of the pollen on maternal tissue outside
the embryo. They confirm earlier observations, hitherto generally dis-
credited, that date pollen has a profound effect on time of ripening and
some other genetic characters.
1925 — (1) T. H. Goodspeed and R. E. Clausen (United States) publish an analysis
of their "artificial species", Nicoliana digluta, showing that this form (which
arose as a fertile seedling from a normally sterile first-generation hybrid)
contains a complete diploid set of chromosomes of each parent species of
the original cross (N. glutinosa L.XiV. tabacum L.). This amphidiploid
("double diploid") is self-fertile but is sterile with the parent species. This
mechanism for the production of fertile polyploids by doubling the chro-
mosome number of sterile first-generation hybrids has been found to be of
rather wide occurrence in plants.
Primula kewensis W. Wats, was the first of the amphidiploids to be
noted. It arose as a fertile branch of a sterile hybrid. The phenom-
enon remained an enigma until Goodspeed 's and Clausen's publica-
tion. Nicotiana digluta explained the origin of a considerable number
of such "artificial new species." Among forms recognized as amphi-
diploids on the basis of Clausen's and Goodspeed's work are Kar-
petchenko's Raphano-Brassica, C. A. Jorgcnseu's Solarium luteo-
nigrum, wheat-agropyron hybrids of the Russian workers, etc. Other
true-breeding interfertile forms, essentially new species, have been
produced by chromosomal rearrangement in Datura.
(2) E. S. McFadden (United States) produces the two wheats, Hope
and H-44, from a cross betwen Marquis wheat and Yaroslav Eiiimer.
In the mature plant stage these wheats have been found to be nearly im-
mune from almost all the physiological races of stem rust now known.
(3) J. A. Clark and E. R. Ausemus (United States) point out that the
near-immune reaction in Hope wheat is a new character in common hard
red spring wheat, inherited as a dominant character. The Hope and H-44
wheats have since become successfully and extensively used in further
breeding for stem-rust control.
(4) East and A. J. Mangelsdorf (United States) offer a genetic interpreta-
tion of self-sterility in Nicotiana as duo to rate-of-growth genes affecting
the pollen tubes.
1926 — (1) Belling advances the segmental interchange theory of chromosome
evolution (exchange of segments between chromosomes that are not
homologous).
(2) J. Percival (England) publishes explanation of polyploid origin of 14
and 21 chromosome wheats.
1472 YEARBOOK, 1937
1927 — (1) Artificial (X-ray) transmutation of the gene, Mullcr in Drosophila
and L. J. Stadler in plants (United States).
The discovery made almost simultaneously by Muller and Stadler
and Goodspeed that X-rays, and by F. B. Hanson (United States)
that radium produces abundant gene mutations is one of the great
bonanzas of modern genetic research. In the short time since this
discovery was made it has been shown that X-rays produce a va-
riety of effects ranging from mutations in a single gene to pro-
found rearrangements and reassortments of entire chromosomes.
Since Muller's original announcement the radiation technique has
been extended to other forms of wave energy. It is impossible to
give in any detail the development in this very widespread and
fertile field of research.
(2) T. S. Painter (United States) finds a chromosome deficiency in
mice which, with associated genetic evidence, establishes the first case in
mammals of locating a definite gene on a definite chromosome.
(3) J. H. Craigie (Canada) reports hybridization of rust fungi to produce
new pysiological forms; reports mutation in rust fungi.
The discovery by Craigie that hybridization of rust fungi is possible
has opened up a wide field of most interesting research in micro-
genetics. Other workers have shown that the disease-producing
fungi that attack plants mutate rather frequently in respect to their
ability to infect and affect a given strain. The problem of the plant
breeder seeking resistance has been enormously increased in com-
plexity by these discoveries, which necessitate methods of protection
by breeding against an enemy whose physiological reactions change
with no visible outward alteration.
(4) Belling, iron-aceto-carmine technique of chromosome staining,
makes possible more detailed studies of chromosome structure.
(5) B. O. Dodge (United States) publishes first report on the genetics
of Ascomycetes (fungi), which have some advantages for genetic research
because their haploid nature makes direct observation of all gene effects
possible. With this material C. L. Lindegren (United States) has recently
produced the first chromosome map of genes in a lower plant.
1930 — (1) Stadler finds that maize genes vary widely in rate of mutation (no
mutation in V/% million waxy gametes, 492 per million in red pericarp [P]
gametes).
(2) H. A. Timofeeff-Ressovsky (Union of Soviet Socialist Republics)
reports induced reverse gene variations in Drosophila, demonstrating that
X-ray effects are not purely destructive.
1930-37 — The perfecting of the gene-frequencv technique for the analysis of
human inheritance bv F. Bernstein (Germany), L. Hogben, J. B. S-
Haldane, and L. S. Penrose (England), A. S. "Wiener and L. S. Snyder
(United States) makes possible much greater precision in the use of pedigree
data, when the samples are too small to allow statistical treatment by
older methods.
1931 — (1) B. McClintock and H. Croighton (United States) in maize, and C.
Stern (Germany) in Drosophila, prove crossing-over cytologically.
(2) McClintock and others of the Cornell group relate maize linkage
groups to specific chromosomes by use of trisomies (diploid plants with
one extra chromosome) .
(3) Cleland and Blakeslee unify Oenothera and Datura cyto-genetic
observations through segmental interchange theory.
(4) Wright gives first comprehensive picture of evolution in Mendelian
terms, with stress on the balance and interplay between selection intensity,
mutation rates, inbreeding, isolation, and migration.
CHRONOLOGY 1473
1932 — (1) L. F. Randolph (United States) produces tetraploid maize by heat
treatment.
(2) Th. Dobzhansky (United States), and Mullcr and Painter show
that "chromosome map" distance and actual (cytological) distance do not
coincide.
(3) Variegation in Drosophila shown to be dependent on chromatin not
organized into chromosomes (hetorochromatin) bv J. W. Gowen and
and E. H. Gay (United States).
(4) J. M. Rasmusson (Norway) formulates hypothesis of interaction of
genes to interpret certain observations of quantative character inheritance.
1934— Painter discovers genetic value of giant salivary gland chromosomes
(discovered many years earlier, but considered a cytological curiosity),
making possible "detailed studies of chromosome structure, and leading
to very exact location of genes.
THE FAMILY TREE OF GENETICS
It is customary to visualize historical development by analogy to a
tree, whose roots go back into the distant past, whose trunk symbo-
lizes a nicely unified development, and whose spreading branches
denote the wide ramifications of our pet discipline at the moment we
are considering it. Under any circumstances such an analogy is
probably hazardous, and with some misgivings we shall symbolize
genetics as a tree which has drawn its sustenance from four main
roots.
These four taproots of modern genetics are: (1) The genetics root,
leading back through Morgan, Bateson, De Vries, Mendel, Koelreuter,
etc.: (2) the cytological root, tracing through Belling, McClung,
Wilson, Sutton, Van Beneden, Leeuwenhoek, to Hooko, who first
saw and named the cell; (3) the biomotrical root, tracing through
Wright, Fisher, Pearson, Galton, Laplace; and (4) the animal-breeding
root, tracing through the stud and herd books, through the breed
founders (such as Bakewellj the Collings, and Bates of a century
ago) to Mago the Carthagenian, who is to be credited with compiling
the first recorded score card — which is still used, with surprisingly
little modification. Other "roots" could also be thought of.
It should bo borne clearly in mind that these roots have generally
been entirely distinct through much of their developmental history.
No experimental connection existed between the observational work
of the hybridizers and that of the microscopists until Sutton in 1902
confirmed Haeckel's prediction (1866) that the nucleus would prove
to be the vehicle of heredity. The observed facts of Mendelian hered-
ity fitted the cytologists' finding that meiosis and fertilization were a
method for keeping the chromosome complement constant. The
heretofore independent concepts wore thus mutually confirmatory and
together made a complete picture. Since that time it has been increas-
ingly difficult to ignore cytology in studying strictly genetic phenom-
ena. Without the cytologist's aid much genetic work would remain
purely speculative. In the case of polyploidy, for instance, cytolog-
ical counts of chromosome number and observation of chromosomal
behavior at the reduction division have been of tremendous importance.
Similarly the mathematical root developed entirely independently
until Galton and Pearson bridged a gap that previously had been so
wide that few students of the subjects involved would have admitted
any close relationship.
1474
YEARBOOK, 1937
1930
The family tree of genetics.
CHRONOLOGY 1175
What of future developments? The chronologer can do no better
than quote one of the greatest geneticists, T. II. Morgan:
I have been challenged recently to state on this occasion what seemed to be the
most important problems for genetics in the immediate future. I have decided to
try, although I realize only too well that my own selection may only serve to show
to future generations how blind we are (or I have been, at least) to the significant
events of our own time.
First, then, the physical and physiological processes involved in the growth of
genes and their duplication (or as we say their "division") arc obviously phe-
nomena on which the whole process of reproduction rests. The ability of the new
genes to retain the property of duplication is the background of all genetic theory.
Whether the solution will come from a frontal attack by cytologists, geneticists,
and chemists, or by flank movements, is difficult to predict.
Second: An interpretation in physical terms of the changes that take place dur-
ing and after the conjugation of the chromosomes. This includes several separate
but interdependent phenomena' — the elongation of the threads, their union in
pairs, crossing over, and the separation of the four strands. Here is a problem on
the biological level, as we say, whose solution may be anticipated only by a
combined attack of geneticists and cytologists.
Third: The relation of genes to characters. This is the explicit realization of
the implicit power of the genes, and includes the physiological action of the gene
on the rest of the cell. This is the gap in our knowledge to which I referred already
at some length.
Fourth: The nature of the mutation process — perhaps I may say the chemico-
physical changes involved when a gene changes to a new one. Emergent evolu-
tion, if you like, but as a scientific problem, not one of metaphysics.
Fifth: The application of genetics to horticulture and to animal husbandry,
especially in two essential respects — more intensive work on the physiological
rather than the morphological aspects of inheritance; and the incorporation of
genes from wild varieties into strains of domesticated types.
Should you ask me how these discoveries are to be made, I should become vague
and resort to generalities. I should then say: By industry, trusting to luck for
new openings. By the intelligent use of working hypotheses (by this I mean a
readiness to reject any such hypotheses unless critical evidence can be found for
their support) . By a search for favorable material, which is often more important
than plodding along the well-trodden path hoping that something a little different
may be found. And lastly, by not holding genetics congresses too often.
It is probable that we are even now witnessing the development of
another major branch of the genetic tree — the biochemical branch. It
has long been guessed that genes must be chemical in their action, and
the molecular nature of the gene has more than once been suggested
and speculated on. Studies of the analysis and synthesis of the sex
hormones, of growth hormones and cancer-producing substances, and
of the filterable viruses are bringing to light effects that closely resem-
ble the action of genes. The next great important advance may be to
link the gene with the newer biochemistry, which will make it necessary
to revise our "genetic tree" and to add another important root tracing
through Wilstetter, Mendeleeff, Dalton, and Lavoisier, to the alchem-
ists of the Middle Ages!
Thus while specialization has been essential to promote the progress
of science, it is distinctly a danger that too much specialization may
endanger continued progress, if it prevents the formation of such
fruitful graft-hybrids in ideas as those that have contributed so greatly
to the progress of genetics. The geneticist and the breeder of the
future must be intelligently cognizant of many fields of knowledge
that are more and more impinging on their chosen specialty. Synthe-
sis of these increasingly complicated factors seems essential if progress
is to continue.
1476 YEARBOOK, 1937
A SELECTED LIST OF REFERENCES TO THE
CHRONOLOGY OF GENETICS
History of Domestic Animals
Beown, W. R
1929. the horse op the deseet. 218 pp., illus. New York.
Burns, R. H., and Mooney, E. L.
1935. the trek op the golden fleece. Jour. Heredity 20: 431-443.
Lush, J. L.
1937. animal breeding plans. 350 pp. Ames, Iowa. See ch. 1.
Morse, E. W.
1912. the ancestrv of domesticated cattle. U. S. Bur. of Anim.
Indus. Ann. Rept. (1910) 27: 187-239, illus.
Prentice, E. P.
1935. breeding profitable dairy cattle; a new source of national
wealth. 261 pp., illus. Boston and New York. See ch. 1-2.
Zirkle, C.
1935. the beginnings of plant hybridization. 231 pp., illus. Philadel-
phia and London.
Early History of Plant Breeding
Babcock, E. B., and Clausen, R. E.
1927. genetics in relation to agriculture. Ed. 2, 673 pp., illus. New
York. See ch. 28.
Roberts, H. F.
1929. plant hybridization before mendel. 374 pp., illus. Princeton,
N. J.
Vries, H. de
1905. species and varieties, their origin by mutation. . . 847 pp.
Chicago.
Zirkle, C.
1935. the beginnings of plant hybridization. 231 pp., illus. Philadel-
phia and London.
Citations of Important Discoveries in Genetics
Babcock, E. B., and Clausen, R. E.
1927. genetics in relation to agriculture. Ed. 2, 673 pp., illus. New
York.
Bateson, W.
1928. scientific papers of William bateson. Edited by R. C. Punnett.
2v., illus. Cambridge, England.
Baur, E., Fischer, E., and Lenz, F.
1931. human heredity. Transl. by E. and C. Paul. 734 pp., illus. New
York.
Castle, W. E.
1930. genetics and eugenics; a textbook for students of biology and
a reference book for animal and plant breeders. Rev. ed. 4,
474 pp., illus. Cambridge, Mass.
East, E. M., and Jones, D. F.
1919. inbreeding and outbreeding; their genetic and sociological
significance. 285 pp., illus. Philadelphia and London.
Gates, R. R.
1929. heredity in man. 385 pp., illus. London.
Morgan, T. H.
1935. the scientific basis of evolution. Ed. 2, 306 pp., illus. New
York.
Sturtevant, A. H., Muller, H. J., and Bridges, C. B.
1923. the mechanism of mendelian heredity. 357 pp., illus. New York.
Sharp, L. W.
1934. introduction to cytology. Ed. 3, 567 pp., illus. New York and
London. See concluding chapters.
CHRONOLOG Y 1477
Sinxott, B. W., and Dunn, L. C.
1932. principles op genetics; a textbook, with problems. Ed. 2, 441
pp., iJlus. New York and London.
Bibliographies
International Congress of Genetics.
1932. proceedings op 6th international congress op genetics. 2 v.,
illus. New York.
Warner, M. F., Sherman, M. A., and Colvin, E. M.
1934. a bibliography op plant genetics. U. S. Dept. Agr. Misc. Pub.
164, 552 pp.
INDEX
Page
Aotinidia, breeding possibilities .. 540-548
Africa, grasses useful in breeding -.. 1030,1078
Agricultural —
byproducts, research 72-73
credit, improvement, discussion by Secre-
tary - - 57-59
production —
control programs, discussion by Secretary. 2-3
long-time effects of soil-conservation
program 17-18
program, long-term, in drought areas 40-48
Agricultural Adjustment Act-
provisions for agriculture •■-- 10-11
surplus-removal provisions in amendment-. 38-40
Agricultural Adjustment Administration- -
benefit payments, statistics 3-7
marketing agreements 01-05
surplus removal by marketing agreement.— 02-03
Agricultural Engineering, Bureau of, research
investigations -- 96-99
Agriculture, Department of —
apple breeding 599-000,614
bee-breeding investigations 1402-
1406,1411,1413,1417
Wackborrv breedin g 507-508, 520
citrus breeding, results 797-799,811.822-823
currant and gooseberry breeding 543
goat breeding 1286-1288
grape breeding 658,660-864
introduction of citrus species and varieties. 816-818
milk goat breeding -■ - 1303-1304
peach-breeding 685-686
plum-breeding 714,720-721
production and testing of apricot hybrids at
Palo Alto, Calif 745-746
raspberry breeding 519, 528,529
strawberry breeding 403-465,486,487
timothy improvement 1105,1106
turkey breeding 1362-1366
work. See also under specific crop or class of
livestock.
Agriculture national policy, discussion by
.Secretary '-18
Alabama Agricultural Experiment Station,
citrus breeding. "05
Alfalfa-
acreage, 1929 1122-1123
articlo on, summary 153-154
bacterial wilt, prevalence 1122, 1130-1132
breeders and workers 1127, 1149-1151
breeding—
experiment stations 1149
methods 1142-1145
objectives 1145
problems — 1128,1129-1132,1145-1146
characters-
correlation, inheritance—. - 1132-1133
supenor.
,,„j . _ 1133
distribution H2S-1125
early breeding work 1126-1128
early history H23- H»
Grimm, development 1125-1126, 1127
hybrid vigor lrS"11?S
hybridization 1133-1136, 1137, 1146
improvements—
H. M. Tysdal and II. L. Westover... 1122-llo3
early efforts 1128-1129
methods and objectives- 1140-1146
projects - 1132-1146
Alfalfa— Continued. Pa£e
inheritance and cytology 1146-1147
insects, relation to improvement work.. 1138-1139
introduction into Americas 1124-1125
natural selection, results 1126-1127
seed sett ing, aid of insects 11 38-1 1 39
selection for disease and cold resistance. . 1136-1138
species-
description and economic importance. 1152-1153
key 1152
types, adaptability 1123
value for soil-improvement. 1122
variety improvement, summary 1150-1161
Alfalfa Improvement Conference, organization
and work 154,1139-1140
Almond-
breeders, list 884
breeding, status in United States 807-869,884
hybridization 868-869
improvement 865-809
Almonds, article on, summary 148-149
Amaryllis, breeding, possibilities 922-926
Arnygdalus communis. See Almond.
Amygdalus perska. See Poach.
Ancuploidv, importance in forest tree breed-
ing. _ 1260-1261
Animal-
breeding, genetic progress 1443-1417
cells, fertilization, process 1420-1421
Animal Industry, Bureau of, livestock inves-
tigations. - 80-85
Animals-
breeding programs and genetic possibili-
ties . - — - 1447-1449
genetic analysis, comparison with plant
genetics 1441-1149
See also Livestock.
Antilles, subtropical and tropical fruit- breed-
ing stations, workers, and work 814
Antirrhinum mains, breeding possibilities.. 965-969
Apis spp. See Bee.
Appalachian Forest Experiment Station,
forest-tree improvement 1207
Apple—
breeder, raw materials used ;>u-o,S
breeders, list 613-614
breeding-
American, objectives 578-580
In Canada. 600-601
in Europe 601,602-604
in United States 592-600, 604-614
requirements for 5i6
work, locations and personnel .... 613-614
chromosome numbers, unusual, signifi-
cance 585-589
crosses, successful experiments, list. - 608-613
early history— 5Z?^II
hybridization technique 581-591
improvement—
by selection of bud mutations, methods . 580-o81
progress. J. K. Magness.. 575-614
seeds, handling for hybridization 583-585
tree and fruit, character inheritance 591-592
triploid varieties, breeding for 590-591
varieties—
development, list 604i,*°
origin, list v,*4"? ''
vegetative propagation studies. 1450-1451,
1452, 1453, 1455
Apples, article on, summary.. 139-140
1479
1480
INDEX
Apricot- FaS«
breeders, list _ 744
breeding—
and workers in United States and other
countries 744
at State and Federal stations- 741-743
in foreign countries 743,744
material available 744-745,746
material, introduction - — 740-741
objectives - 741
distribution and production 738
foreign types 739-740
genetics and cytology 743
history and botanical relationships _ _ 733-740
hybridization work 741-743
hybrids, production and testing at Palo Alto,
Calif__ 745-746
improvement . 738-746
seedlings, growing at California Agricul-
tural Experiment Station, Davis, Calif. 742, 744
varieties, of interest to breeders - 740-74 1
Apricots, article on, summary .. 144
Arizona, grapefruit industry. 779
Ashbhook, Frank G.: The Breeding ol Fur
Animals.. 1379-1305
Asia-
citrus improvement 789
grasses useful in breeding 1035-1036, 1077-1078
subtropical and tropical fruit-breeding sta-
tions, workers, and work. . 812-813
Asparagus-
breeders, list 365,366,367,369
breeding—
and improvement in foreign countries 375
State and Federal agencies. 365, 366, 367, 369
varieties, strains, and breeding lines, in cul-
tures of State and Federal research agencies. 362
Astragalus, improvement, possibilities... 1000
Austin, Lloyd, recommendations on forest
improvement. 1261
Australia-
alfalfa breeders, list. 1149
citrus improvement 790
clover breeders, list 1214
grape breeding 653
peach breeding 687
jjlum breeding and workers 717
soybean workers, list.. 1185
strawberry breeding 470
subtropical and tropical fruit-breeding sta-
tions, workers, and work 814
vegetable breeding and improvement 371-373
Austria, forest-tree improvement 1277
A vocado, farm value, 1934-35 751
Bahia grass, climatic adaptation 1042
Bankhead-Jones Act-
projects—
of Bureau of Chemistry and Soils 71-74
under, discussion by Secretary 37-38
provision tor-
establishment of vegetable breeding labor-
atory 123-174
establishing and operating regional re-
search laboratories 111-112
Bean —
Adzuki, inheritance studies 1017
breeding-
activities of State and Federal agencies-.. 341,
351, 365, 366, 367, 368, 369, 370
and improvements in foreign countries — 371
373,375,376,377,378
improved varieties, development by State
and Federal research agencies 342-343
varieties, strains, and breeding lines, in cul-
tures of State and Federal research agen-
cies. --- 350-351
See also jPhaseolus.
Beans-
ami peas, breeding and improvement. B. 7,.
Wade. 251-282
article on, summary 127-128
breeding at experiment stations... 264-265,266,268
disease resistance, genetics of 275-276
genetics, research— 273-277
improvement - 260-268
Beans— Continued. Pa£e
lima—
characteristics, origins, and breeding 267-268
genetics, research.. 277
snap-
breeders.... 261-268
culture, disease factors... 262-263
history and classification 260-26 1
newer varieties, prod uction 263-267
older varieties, origin 261-262
See also Phaseolus.
Bee-
breeder—
objectives... 1401-1402
progress, factors aifeeting '- 1397-1399
breeding—
W.J.Nolan 1396-1418
economic importance 1396-1397
in foreign countries 1408-1409, 1418
in United States 1402-1408,1417
possibilities 1397
private agencies _. 1407-1408
results 1411-1415
technique, geographical development 1409
use of mating stations... 1400-1401,1409
characters, linkage 1415
chromosomes —
numbers. .. . 1409
types 1409-14)0
colonies, value in United States.. ... 1396
coloration, inheritance . 1407,1409-1415
crosses, dominance and reeessiveness 1415
cytology 1409-1411
genetics 1409-1411
improvement, workers, list 1417-1418
industry, value in United States 1396
mating stations, improvement program 1400-
1401, 1409
queen-
artificial insemination, technique 1398,1403-
1404
breeding practice 1400-1401
races—
biometric data 1404-1405, 1407, 1408, 1413
worker characters 1401-1402
reproductive process, information 1399-1400
worker, characters, by races 1401-1402
Beekeepers, maintenance of bee-mating sta-
tions 1400-1401
Beer making, use of hops 1215-1216
Bees, article on, summary 165-166
Beet-
breeding—
activities of State and Federal agencies ... 362,
368, 370
and improvement in foreign countries 371
for improved varieties 304-306
chromosome number 306
genetic studies 319-321
improved variety, development by State and
Federal research agencies 349
varieties, strains, and breeding lines, in
cultures of State and Federal research
agencies _ 362
Bcggarweed, improvement, possibilities 1000
Belgium, timothy-breeding projects 1121
Bentgrasses, climatic adaptation... _ 1040-1041
Bermuda grass, introduction and adaptation . 1041-
1042
Biological Survey, Bureau of, wildlile conser-
vation program 94-96
Blackberries, articles on, summary 135
Blackberry—
and raspberry improvement. George M.
Darrow— 496-533
botanical history and names of breeders.. 501-503
breeders —
list 526,527
problems and objectives 509
breeding-
objectives 526
work, Department 507-509
work, experiment stations 506,526
chromosome numbers 532-533
colors, varied, description 513-514
INDEX
1481
Blackberry— Continued. P»S0
crossing, technique _.. 522-523
early history and origin 496-497
evolution in Europo and distribution 505
hybridizing for varietal improvement 506-508
improvement work.- __ __ 496-509
Logan, development and related species.. 503-505
plant and fruit characters, superiority. 527
qualities of value to breeders _. 499-501
superior qualities-
list 526-527
sourco 527
thornless sports, value 505-506
varieties —
derivation _ 501
early breeding stock 496-497
originated by private agencies 527
originated by public agencies 52fi
wild-
groups, description 497-501
hybrids, value 498-501
sourco of cultivated varieties 497-501
Blackberry-raspberry hybrids-
characteristics.. 504
growing in England and Germany 508
value _ 516-517
Blister rust, white-pine, spread, relation of
currants and gooseberries to 536-537
Blueberries —
articles on, summary 138
testing, important factors 566-568
wild, use of, best for breeding purposes... 559-561
Blueberry —
Brooks, selection for breeding __ 561
Cabot, development 569
Catawba, development 572
chromosome numbers 562-563
Concord, development 570
cross-pollination, success 563-565
Dixi, development 573-574
flavor, tests 566-568
OM37, development . 573
Greenfield, development 569
hybrids, first generation. _ 563-565
improvement through self-pollination, fail-
ure '561-562
Jersey, development 570
Juno, development... 570-571
Katherinc, development 569
Pioneer, development 568
propagation for new varieties 568
Rancocas, development 569-570
Eedskin, development _ _ 571-572
Russell, selection for breeding 563
Scammell, development 571
seedlings, pedigroed, tests to obtain fifteen
named varietios 565-568
Sooy, selection for breeding 565
Stanley, development 571
varioties, improved, list... 568-574
Wareham, development 572
Weymouth, development 572-573
wild, improving. Frederick ,V. Coville... 559-574
Blucgrass—
Canada, introduction and adaptation... 1039-1040
Kentucky, introduction and adaptation. 1 039-1 040
Bonavist —
improvement, possibilities 1001
inheritance studies 1016
BOSWELL, VlCTOB It.—
Improvement and Genetics of Tomatoes,
Peppers, and Eggplant 176-203
Improvement of Vegetable Crops-
Appendix 310-378
Vegetable Crop Breeding and Improve-
ment—An Introduction 171-175
Brasska—
breeding and improvement in foreign
countries 375
genetics and cytology 292-298
hybrids, varieties, strains, and breeding
lines, in cultures of State and Federal
research agencies 352
Brassicas—
American improvements 289
biennial, breeding method 288
brooding tochnique, developments.. 289-292
138904°— 37 04
Brassicas— Continued. Page
improvement 283-298
loaiy types, cytology and genetics 292-298
linkage 298
See also Crucifers; and under specific kind.
Brazil, vegetable breeding and improvement
work 373
Breeders, of —
alfalfa, list. 1127,1149-1151
almonds, list _ 884
apples, list _ 613-614
apricots, list 744
asparagus, list. _ 365,366,367,369
bees, list 1417-1418
black walnuts, list 885-886,888-889
blackberries, list 526,527
butternuts, list 884,888
cherries, list 736
chestnuts, list 885
citrus, list 811-815
clover, list 1213-1214
dogs, list. 1331-1341
filberts, list 885,886
forest trees 1264-1266
fruit, subtropical and tropical, list 811-815
grasses, list 1081-1093
hickory, list 885,886-887
hops, list 1240-1241
Japanese walnuts, list 886,889
kale 369
muskmolon, list 367,368, 370, 372, 376
nuts, list 884-889
peaches, list 678-681,696-097
pears,list 628
pecan, list 885,887-888
Persian walnuts, list 886,889
plums, list 709-711,717
raspberries, list. 527-528,530
snapbeans 261-268
soybeans, list __ 1184-1185
strawberries, list 486-493
subtropical and tropical fruits, list 811-812
sweet corn 381,383-387
tung tree, list.. 885
Breeding —
fundamentals of heredity. E. N. Bress-
man._ 1419-1449
importance in potato improvement. F. J.
Stevenson and O. F. Clark 405-444
See also under specific crop.
Beessman, E. N.: Fundamentals of Heredity
for Breeders. __ _ 1419-1449
Browing interests, hop requirements. 1218-1219
Bbiekly, Philip: Improvement of Flowers by
Breeding. With S. L. Emsweller, D. V.
Lumsden, and F. L. Mulford 890-998
Broccoli-
breeding —
activities of State and Federal agencies... 369
and improvement in foreign countries 374
research work, results 283, 289, 292, 293
Bromegrass, awnless, introduction and clima-
tic adaptation 1042-1043
Brooklyn Botanic Garden,forest-tree improve-
ment 1251,1264,1275-1276
BnuNSON, Arthur M.: Popcorn Breeding. 395-404
Brussels sprouts —
breeding-
activities of State and Federal agencies. .. 366
and improvement in foreign countries 374,
375, 377
research work, results 283-284,292,293,296
Bur-clover, improvement, possibilities — 1001-1003
Butternut-
breeders, list 884,888
improvement 859
Cabbage-
article on, summary.. . ... .. — -. 128-129
breeding—
and improvement in foreign countries 371 ,
373, 375, 376, 377
at cxperimen t stations 286-289, 292, 294
for resistance to yellows 284,
286-287, 289, 290, 297-298
State and Federal agencies 343,
353, 385, 366, 367, 368, 369, 870
1482
INDEX
Cabbage— Continued. 1 see
development by seedsmen 284-286
family, improvement— _ __ 283-298
improved varieties, development by State
and Federal research agencies 342-343
varieties-
lists _ 285-286
strains, and breeding lines, in cultures of
State and Federal research agencies.— 352,353
yellows, resistance to, breeding for._ _ 284,
286-287, 289, 290, 297-298
Cajanus indicus. See Pigeonpea.
California —
grapefruit industry 779
lemon industry, development- 781-782
sweet-orange varieties, improvement 770-772
California Agricultural Experiment Station,
Davis, Calif.—
apricot seedlings available 742, 744
cherry-breeding stock available 737
peach and nectarine breeding material avail-
able 1 698-700
plum-breeding stock available... 721-724
California Citrus Experiment Station, River-
side, Calif.—
citrus breeding 803-804
discovery of citrus bud mutations, 1809-36. 824-825
California Forest and Eange Experiment Sta-
tion, forest-tree improvement 1244-1246,
1248, 1204, 1265, 1266, 1267-1269
Callistephus chintnsis, breeding, possibili-
ties 926-929
Canada —
alfalfa-
breeders, list 1149
variety improvement, summary 1150-1151
apple breeding 600-601
cherry-
breeders 736
breeding woik.. 733,736
clover breeders, list 1214
forest-tree improvement _. 1278
grass breeding... 1087-1088
peach breeding.... 686-687,696-697
plum breeding and workers 715,717
raspberry breeding 519-520
selective breeding of grasses. 1051-3055
soybean workers, list 1185
strawberry breeding 469
timothy-breeding projects 1120
Canna, breeding, possibilities.- 929-932
Cantaloup —
breeding, State and Federal agencies 365, 366
improved varieties, development by State
and Federal research agencies __ 346
varieties, strains, and breeding lines, in cul-
tures ot State and Federal research agen-
cies __ _ 355,356
See also Melon; Muskmelon.
Caraway, breeding and improvement in for-
eign countries 375
Carbohydrate, percentage in sweet-corn
kernels 391
Carnation, breeding, possibilities 932-935
Carpet grass, climatic adaptation 1042
Carrot-
breeding—
and improvement 306-307
and improvement in foreign countries 377
State and Federal agencies 366, 367
cross-pollination technique 311
crossing for hybrid vigor 322
genetic studies 321-322
improved variety, development by State and
Federal research agencies 349
varieties, strains, and breeding lines, in
cultures of State and Federal research
agencies 362
Cahtter, J. L.: Improvement in Soybeans.
With W.J. Morse - 1154-1189
Castanea dentata. See Chestnut.
Cattle-
situation, effect of drought 53
See also Livestock.
Cauliflower— l'wso
breeding and improvement in foreign coun-
tries _ 374,377
research, results 283,292
Celery —
article on, summary... 130-131
breeding—
and improvement in foreign countries 372
State and Federal agencies. 365, 366, 367, 360
hybrid, in cultures of State and Federal
research agencies 352
importance as salad crop.. _ 335-337
improved varieties, development by State
and Federal research agencies : 342
improvement for disease-resistant strains. 336-337
inheritance studies 338-339
varieties, history 335-336
Cell division, in vegetative tissues, studies.1451-1453
Cells, fertilization, process 1419-1422
Central Africa, subtropical and tropical fruit-
breeding stations, workers, and work 813
Central America —
grasses useful in breeding 1037, 1078-1079
subtropical and tropical fruit-breeding sta-
tions, workers, and work 8J4
Central States Forest Experiment Station,
forest-tree improvement 1269
Chemistry and Soils, Bureau of, research work,
discussion by Secretary _ 71-78
Cherries —
article on, summary1 143-144
commercial production 665
Cherry-
breeding—
and workers in United States and Canada. 736
in Canada 733
in United States 730-733
material, available 732-733,737
methods 729
objectives 727-729
possibilities 555-558
characters, inheritance 734-736
Chinese, breeding possibilities 555-558
distribution in United States and com-
mercial use _ 724-725
genetics and cytology 734-736
groups, description 725-727
hybridization 730-733
improvement... 724-737
qualities desirable to growers 727-729
species, chromosomes, numbers.— 735
varietal improvement 729-730
varieties —
classification _. 725-727
in use by New York Agricultural Experi-
ment Station, Geneva, N. Y 737
incompatibility tests 733-734
sterility types __ 734
Chestnut —
blight, effect on chestnut forests 828
breeders, list 885
breeding, present status in United States. 828, 835
early introductions, developments 829-831
hybridization, possibilities. 831-832
improvement 827-835
varieties, defects and merits 833-835
Chestnuts, article on, summary 147
Chickpea-
improvement, possibilities 1003
inheritance studies 1014-1015
China-aster, breeding, possibilities 926-929
Chromosomes —
behavior in —
second-generation progeny 1422-1432
tomato... 197-198
wheat 1421
linkage and crossing over. 1432-1440
mutation. __ __ _ 1440-1441
new studies 168-169
numbers-
importance in forest-tree breeding 1260-1261
in different plants 312-313
in legumes, list 1019-1027
in vegetative tissues 1451-1453
irregularities 917-922
of various grasses 1067-1069,1094-1099
INDEX
1483
Chromosomes — Continued. ly
numbers — continued. J- use
unusual, significance in apple and pear
breeding- 585-589
See also under specific crop.
sex linkage 1438-1140
somatic, number in nut-producing species,
list 884
typos in bee 1400-1410
Chrysanthemum, breeding, possibilities 935-938
Cicer arietinum. See Chickpea.
Citron-
chromosomes, numbers.- 792,815
introduction by Department of Agriculture. 817
varieties, introduction 782
Citrus—
aurwntifolla. See Lime.
breeder, objectives 703-784, 705, 788-790
breeders, list 811-815
breeding —
achievements and possibilities 764-705
by Department of Agriculture, sum-
mary 822-823
materials 758-700
methods 702-703,795-797
problems peculiar to 700-702
results, work of Department bl Agricul-
ture 797-799,805
technical problems andresults— 791-800
bud mutations 750,
770, 778, 783-785, 790, 824-825
capacity for vitamin production, inherit-
ance- 802-803
chromosomes, numbers 792-793,815
crosses, with other citrus 797-799
disease resistance, inheritance 800-802
diseases 763-764, 800-802
fruit, growing in—
Hawaii _ 757
Philippines 757-758
Puerto Bico.._ 757
fruits-
acid, improvemen; 780-782
article on, summary 144-145
character and uscs__ 759-760
early history 752-753
farm value, 1934-35.- 751
minor, improvement 782-783
producing areas in United States 752
production and value in United States,
1934._ _ 751
regional characteristics in United States.. 753-75"!
genetics 791-794,799-803
grandis. See Grapefruit; Puinmelo.
hybridization _. 797-800,822-823
hybrids, character and uses 759-760
improvement-
Hamilton P. Traub and T. Ralph Robin-
son 749-825
at experiment stations 704-705,
780, 783, 78 1-785, 803-800
by bud selection. 783-785, 790
in foreign countries 788-790
trends and problems— 760-705
industry, development in —
central irrigated region 756-757
southeastern humid region.- 753-755
southwestern irrigated region 755-756
inheritance of characters— 799-800
timonia. See Lemon.
medica. See Citron.
nobilis var. delichsa. See Orange, tangerine.
nobilis var. unshin. See Orange, Satsuma.
pollination technique. 762
polyembryony 761-762, 794-795, 796-797
related genera 758,760,819-821
relatives, introduction by Department of
Agriculture 760,819-821
rootstock, selection 786-787
sinensis. See Orange, sweet,
species—
and varieties, introduction by Department
of Agriculture 816-818
crossing with trifoliate orange 798-799
susceptibility to disease 801
superior strains, buds sold 781
Citrvs — Continued,
varieties— *■ a£e
crossing with mandarin orange 797-798
value as rootstocks 785-787
variety improvement _ 705-782
Clark, C. F.: Breeding and Genetics in
Potato Improvement. With F. J. Steven-
son.. _ 405-444
Clover—
alsikc, characteristics- 1203
annual, commercial unimportance 1203
articles on, summary 155-156
breeders, list 1213-1214
breeding by Department of Agriculture. 1193, 1213
chromosomes, numbers 1213
crimson, characteristics 1203
genetics.- 1208-1211
importance in agriculture. _ 1190
i mprovement—
A. J. Picters and E. A. JTollowpll 1190-1214
by kinds, locations, and workers 1213-1214
rod-
breeding methods 1199-1201
classes and varieties 1192-1193
cytology 1209
disease-resistant strains, development 1193-
1196
distribution 1190-1191
fertility and pollination relationships. 1197-1198
genetics 1208-1209
hairiness, development 1191-1192
hybridization— 1199-1201
improvement 1190-1201
improvementin foreign countries 1196-1197
improvement in United States.- 1193-1196
introduction into America 1191-1192
natural development 1 1 91 -1 1 92
pollination by insects _ _. 1199
regional needs _ __ 1191
self fertility, effect on progeny. 1198-1199
variations 1191
white-
breeding investigations 1202-1203
genetics and cytology... 1209
history 1201
improvement 1201-1203
variations 1202
varieties and forms, origin 1201-1202
Collards—
breeding, State and Federal agencies 366
improved variety, development by State
and Federal research agencies. 342
research, results.. 283, 289, 292
Commodity Exchange Act, provisions 106-107
Commodity Exchange Administration, work. 106-
107
Cook, Robert: A Chronology of Genetics. _. 1457-
1477
Cooperative extension work, discussion bv
Secretary 107-110
Corn-
adjustment under Agricultural Adjustment
Act, discussion by Secretary 10, 1 1
popping quality 395
sweet —
articlcon, summary _ 131
breedersof, work 381,383-387
breeding and improvement in foreign
countries __ 372
breeding for marke t varieties. 389-390
breeding in United States. . 349, 361, 371, 381-390
breeding, State and Federal agencies 365,
366, 307, 368, 369, 371
canning varieties _ 382-383
carbohydrate percentages for whole ker-
nels 391
cultivation, geographic range 379
ear characters, inheritance. 392
early history and varieties 379-381
endosperm, chemical composition 391-392
genetic studies.— 390-392
hybridization, early work 380-381
hybridization technique... 385-387
improved varieties, development by Si ate
and Federal research agencies 347-349
improvement. C.F.Poole 379-394
inbreeding, importance to canners 380
] J 84
INDEX
Corn— Continued. Pago
sweet— continued .
pseudostarchy, investigations 391
qualities for market and canning varieties- 382
top-crossing, value _.. 387-388
varieties, strains, and breeding lines, in
cultures ol State and Federal research
agencies 359-362
Corn-hog income, distribution, discussion by
Secretary 53
Corvallis, Oreg., hop varieties and seedlings,
physical and chemical analyses _._ 1229
Corylus spp. See Filbert.
Costa Rica, vegetable breeding and improve-
ment work 373
Cotton-
adjustment under Agricultural Adjustment
Act, discussion by Secretary.-. 10,11
export trade, obstacle, discussion by Secre-
tary ._ 49
situation, 1934-30, discussion by Secretary... 48-49
varieties, development 88-90
Cover crop legumes, and miscellaneous forage.
Roland McKee and A.J. J'ieters _ 999-1031
Cover crops, article on, summary.. 130-151
COVILLE, FREDERICK V.—
death notice 500
Improving the Wild Blueberry 559-574
Cowpea—
improvement, possibilities. 1003-1004
Inheritance studies 10L6-101C
Cranberry bush, American, breeding pos-
sibilities „ 548-550
Crane, H. L.: Nut Breeding. With O. A.
Reed and M.N. Wood 827-889
Credit, agricultural, improvement, discussion
by Secretary 57-59
Crop insurance, nature and purpose, discus-
sion by Secretary - 44-47
Crops—
leafy-
improved varieties, development by State
and Federal research agencies 342-343
varieties, strains, and breeding lines, in
cultures of State and Federal research
agencies 351-353
miscellaneous —
improved varieties, development by State
and Federal research agencies 349-350
strains, varieties, and breeding lines, in
cultures of State and Federal research
agencies 302-3(54
See also under specific kinds.
Cross-breeding. See under specific crop or
class of livestock.
Crotalaria, improvement possibilities 1004-1005
Crucifer hybrids, varieties, strains, and breed-
ing lines, in cultures of State and Federal
research agencies 352
Crucifers —
inbreeding aspects 309-311
leafy, improvement. Roy Magrudor 283-299
root, improvement program 301-304
See also Brassieas; and under specific kind.
Cucumber —
breeding—
and improvement 210-213
and improvement in foreign countries 372,
373, 374, 370, 377
for disease resistance 213
State and Federal agencies.. 358, 366, 367, 368, 370
English variety, importance in development
of American varieties 172
improved varieties, development by State
and Federal research agencies 347
inheritance studies 228
varietal improvement 210-2J2
varieties, strains, and breeding lines, in
cultures of State and Federal research
agencies 357,358
Cucurbita, breeding and improvement in
foreign countries 376
Cucurbits-
article on, summary 124-125
breeding-
activities of State and Federal agencies.. 367, 368
Cucurbits— Continued,
breeding— continued. Page
and improvement. T. W. Whitaker and
1. C. Jagger 207-231
responses and pollination technique 208-210
improved varieties, development by State
and Federal research agencies 346-347
inheritance studies.. 227-231
varieties, strains, and breeding lines, in
cultures of State and Federal research
agencies 355-358
Cullinan, F. P.: Improvement of Stone
Fruits 665-748
Currants—
and gooseberries, improvement. George M.
.Darrow 534-544
article on, summary 130, 137
breeding-
Department of Agriculture 543
experiment stations. 541-544
in foreign countries 543-544
material _ 534-538
English introductions, list 544
relation to white-pine blister rust 536-537
species, distribution 537-538
systematic breeding 540-544
Cytology-
importance in breeding potatoes 428-434
of popcorn, similarity to cytology of corn 404
Czechoslovakia—
fruit-breeding stations _ 602
grape-breeding %vork 650
vegetable breedingandimprovement 373-374
Dahlia, breeding, possibilities 938-942
Dairy-
byproducts, utilization, discussion by Secre-
tary 78-80
products, prices, 1934-36, discussion by Secre-
tary.. 54-55
Dairy Industry, Bureau of, investigations 78-80
Dairying, improvement, factors affecting, dis-
cussion by Secretary 54-55
Dallis grass, introduction and adaptation. 1041-1042
Darrow, George M.—
Blackberry and Raspberry Improvement. 496-533
Improvement of Currants and Goose-
berries..- 534-544
Some Cnusual Opportunities in Plant
Breeding. With Qny E. Yerkes. 545-558
Strawberry Improvement 443-495
Dasheen. See Taro.
Date, farm value, 1934-35 751
Dawson, W. M.: Heredity in the Dog... 1314-1349
Daylilies, breeding possibilities 945-947
Denmark—
forest-tree improvement 1247, 1253, 1278
vegetable breeding and improvement 374
Dewberry, early history and origin 496-497
Dianthuscaryophytlns, breeding, possibilities. 932-935
Diet statistics, value, discussion by Secre-
tary .._ 104-105
Dill, breeding and improvement in foreign
countries 375
Dog-
allelomorphic color series 1343
body characters-
description 1319-1321
inheritance, research 1332-1336
breeders, list 1331-1341
characters, inheritance, studies by research
workers 1331-1343
color inheritance 1337-1343
genetics-
future possibilities 1326-1328
present status.. 1318-1321
inheritance studies 1315-1349
mental characteristics and temperament 1319
origin and domestication 1316-1318
psychological inheritance, studies 1317
shows, value _ _. 1325-1326
variation, in size and color 1315-1316
Dogs-
ability, in competition, measurement-.. 1321-1326
article on, summary 161-162
as farm animals, value... 1317-1318
hunting and herding, field trails 1323-1325
INDEX
1485
Dogs-Continued. PaS°
mental aptitudes, inheritance research.- 1331-1332
nonsporting, color, weight, and uses, list 1349
sporting, color, weight, and uses, list 1344-1345
toy, color, weight, and uses, list 1348-1349
use in track and sled racing 1322-1323
working —
color, weight, and uses, list 1346-1347
common colors and color patterns in,
formulas 1343-1349
Dolkhos labtab. See Bonavist.
Donahue, Eoy L., recommendations on forest
improvement 1264
Drought-
causes, discussion by Secretary. _ 35-36
effects on—
farm crops, discussion by Secretary 32-33
livestock situation 52-53
poultry industry 57
truck crops. 56
regions, long-term agricultural program 40-48
relief, measures under Agricultural Adjust-
ment Act, discussion by Secretary 38-40
Duck-
breeding —
A. B. Lee._ 1367-1378
for disease resistance. 1373-1374
for egg production 1375-1376
for improvement _. 1370-1732
for meat production- 1374-1375
for size and quality of flesh. 1372-1373
limitations 1367
principles 1372
cross-breeding __. 1373
eggs, size and color, improvement 1376-1377
genetics _ 1377
inbreeding and hatchability 1373
Ducks-
article on, summary _ 163-164
domestic, origin and history 1368-1377
green, production 1367-1368
Dunning, Duncan, recommendations on forest
improvement 1264
East Africa, citrus improvement 790
Eggplant-
article on, summary 124
breeding —
and improvement in foreign countries 375
State and Federal agencies 367, 368, 369
history and value 192-193
improved variety, development by State and
Federal research agencies 350
improvement and genetics, Victor It. Bos-
well.. 192-194,202-203
inheritance studies.. - '---- 202-203
variety and breeding lines, in cultures of
Stato and Federal research agencies 354, 355
Elaeagnus spp., breeding possibilities 551-553
Emsweller, S. L.: Improvement of
Flowers by Breeding. With Philip
Brierly, D. V. Lumsden, and F. L. Mul-
ford _ 890-998
England—
blackberry-raspberry hybridization SOS
fruit-breeding stations _ 602-603
peach —
breeding 687
genetic studies 694-695
plum-breeding work and workers 717
raspberry breeding 520
soybean workers, list 1185
strawberry-
breeding and breeders... 469, 492-493
varieties of importance 454
vegetable breeding and improvement 374
Erosion, soil, control methods, discussion by
Secretary 18-22
Etteb, A. F., pioneer breeder of strawberries.. 463
Europe —
apple breeding 601,602-604
citrus improvement 788-789
forest-tree breeding 1244, 1247, 1253, 1 277-1279
grape improvement in, development 649-650
grasses useful in breeding 1034,1077
subtropical and tropical fruit-breeding
stations, workers, and work 812
Page
Evans, Morgan ~\\'.: Improvement of
Timothy 1103-1121
Experiment stations-
alfalfa breeders, list 1149
apple breeding 592-599, 604-614
apricot breeding _. 741-742,744
bean breeding 264-265,266,268
bee breeding - 1406-1407,1417
bee improvement, workers 1417
blackberry breeding. 506,526
cabbage breeding 286-289, 292, 294
cherry breeding 730-733
citrus improvement 764-765,
780, 783, 784-785, 803-806
currant and gooseberry breeding— — 541-543
feed crops, breeding — 150-151, 153, 155-156
forest-tree breeding 1244,
1247-1248, 1252-1253, 1264-1275
fruit breeding 134-137,139-145
grape breeding 656-660
grass breeding 1052, 1053-1055, 1084-1088
hop breeding 157
hop improvement and workers 1222, 1240-1241
nut breeding 147-149
pea breeding 258,259
peach breeding and breeders. 681-685
pear breeding... 620-623,628
plum breeding.. 711-714, 717, 719-720, 721-723
popcorn breeding 399-404
potato breeding 414-416
raspberry breeding 611-513,514-519,527-528
red clover improvement 1193-1196
soybean workers, list 1184-1185
strawberry breeding and breeders 463,
464, 465-469, 486-489
subtropical and tropical fruit breeding and
workers _. 811-812
sweet-corn breeding 383-385
timothy improvement 1105-
1106,1114-1115,1120,1121
tomato improvement 182-187
tung-tree breeding. 870
turkey breeding 162, 163, 1361-1362
vegetable breeding 123-
125, 127, 128, 130-133, 365-378
work. See also under specific crop or class of
livestock.
Experiment Stations, Office of, cooperative re-
search projects 110-113
Extension Service, cooperative work 107-110
Farm-
equipment, improvement, discussion by
Secretary 96-98
lands, values, increases, discussion by Secre-
tary 26-27
products-
exchange value, discussion by Secretary.. 4-6
foreign trade in, discussion by Secretary. 27-31
marketing problems, discussion by Secre-
tary 63-65
real estate, situation, discussion by Secre-
tary 59-61
recovery, progress, discussion by Secretary. 1-3
Farm Credit Administration, loans to farmers. 58-39
Federal Reserve System, farm-mortgage loans. 58
Fenugreek, improvement, possibilities 1005
Fertilization, in —
nut-producing plants, factors affecting 877-878
plants and animals, process _ 1419-142?
Fertilizer-placement studies 93-94
Fertilizers, improvement studies 76-77
Fig, farm value, 1934-35 751
Filbert-
breeders, list 885,886
breeding-
material available 841-842
present and future possibilities.. 842-844
cross-pollination, need for 837-839
hybridization 842-844
improvement- 835-844
Filberts-
article on, summary 147-148
European, growing in eastern United
States _ _ 839-841
1486
INDEX
Page
Flood Control Act, provisions 22
Florida-
grapefruit varieties, improvement 777-778
lemon varieties, improvement 780-781
limo improvement 781
sweet-orange varieties, improvement 766-770
Florida State Citrus Experiment Station,
citrus breeding 805
Florist trade, history and investments 890-801
Flower-
breeders, amateur and professional, work.. 891-894
breeding —
achievements and possibilities 922-977
history. 891-898
methods, scientific, need for 894-898
study of cells __ 915-922
genetics and cytology 915-922
germ plasm, changing, by artificial methods
913-915
mutations, occurrence 910-912
Flowers-
article on, summary 149-150
breeding technique 898-915
chromosome numbers 910-912,915-922
hybridization, methods.. 908-910
improvement —
by breeding. S. L. Kmsweller, Philip
Erierly, D. V. Lumsdcn, P. L. Mulford
890-998
through mass selection and line breeding- 907-908
superior types, producing, methods 907
Food and Drugs Act, enforcement- 113-114
Forage-
crops, article on, summary 150-151
miscellaneous, and cover crop legumes.
Eoland McKee and A. J. Pielers 999-1031
Foreign countries —
bee breeding 1408-1409,1418
bee improvement, workers 1418
citrus improvement 788-790
clover breeders, list 1214
currant and gooseberry breeding 543-544
grass-breeding stations 1055-1056
hop improvement 1 222-1 223, 1 232, 1238-1238
peach breeding 686-688
plum breeding and workers 717
raspberry breeding 519-520
red clover improvement 3190-1197
soybean workers, list 1185
strawberry —
breeding and breeders 469-470
varieties of importance 453-454
subtropical and tropical fruit breeding sta-
tions, work, and workers 812-815
timothy improvement 1107,1115
vegetablo breeding and improvement 371-378
Foreign trade, in farm products, discussion
by Secretary 27-31
3T OFPS t
genetics 1255-1257,1263-1266
stock, superior germ plasm, selection. 124(1
trees. See Trees, forest.
Forest Service, research work 85-88
Forestry-
practices, change in viewpoint 1243
research, discussion by Secretary 85-88
Fortunella spp. —
crossing with trifoliate orange 798-799
See also Kumquat.
Fox-
breeding methods. 1386-1387
farming, development 1380,1384-1386
genetics 1380,1390-1394
rod, mutations 1380
Fox Research Forest, forest-tree improve-
ment.-. __ 1276
Foxes-
inheritance studies ..- 1388-1394
red, cross, and black, genetic relation-
ships 1390-1394
s il ver, market requirements -_ 1 387-1388
Fragaria. See Strawberry.
France-
grape breeding 650
strawberry varieties of importance 'loi
Page
Frost, Howard B., breeder of citrus. 764,
772, 779, 787, 792, 793, 794, 795, 796, 797, 800
Frost tolerance, development in potato hy-
brids 418
Fruit-
breeding—
stations in Europe, list 602-604
work of experiment stations 134-137, 139-145
crops, subtropical, improvement. Ham-
ilton P. Traub and T. Ralph Robinson. 749-825
trees, improvement, breeding possibilities. _ 54(1
Fruits-
bush, unusual-
article on, summary 137-138
breeding possibilities 546-558
production, 1934-36 56
solanaceous, inheritance and cytology, stud-
ies-— 194-203
stone-
article on, summary _._ 142-144
blossoms, bagging after pollination 669-671
botanical relationships. 666-667
breeding methods 667-672
characteristics 666-067
drying and treatment of pits 671
flower structure 668
germination of seeds 671-672
improvement. F. P. Cullinan 665-748
improvement, early history 665-666
pollination technique 668-671
subtropical-
article on, summary 145-147
breeding stations and workers in United
States 811-812
breeding stations in foreign countries,
workers, and work 812-815
history 749-751
of Rutaceae, chromosome numbers 815
tropical —
breeding stations and workers in United
States __. 811-812
breeding stations in foreign countries,
workers, and work 812-815
history _ 749-750
of Rutaceae, chromosome numbers 815
vegetative reproduction studies J450-1456
Fur-
animal breeding, research program, recom-
mendations 1394-1395,1383
animals —
article on, summary 164
breeding. Frank G. Ashbrook 1379-1395
raising in captivity _ 1382-1388
resources, conservation efforts .. - 1379-1380
Furs, production and demands for 1380-1381
Game refuges, projects and improvements 95-96
Garet, T. A., pioneer in citrus introduction.. 755
Garlic-
culture and improvement 247-248
varieties, strains, and breeding lines, in cul-
tures of State and Federal research agen-
cies 362
Generic crosses, in strawberry, results 480-481
Genes —
in soybeans, list 1185-1186
mutation 1440-1441
several pairs, inheritance ratios 1427-1428
sexlinkage . _ 1438-1440
Genetics-
analysis, plant and animal comparisons. 1441-1449
animal-
possibilities and breeding programs.. 1447-1449
problems 1443-1447
background 1459-1460
birth, 1760-1900 1460-1464
chronology-
Robert Cook 1457-1477
1694 to recent developments 169-170
early-
days.... .1464-1469
history... 1457-1459
family tree _ 1473-1475
INDEX
1487
Genetics — Continued. Page
importance in —
breeding Angora goats __ 1288-1289
breeding apricots... 743
breeding bees 1409-1411
breeding beets 319-321
breeding carrots. .__ 321-322
breeding cherries „_'. 734-738
breeding clover ...... 1208-1211
breeding ducks . . 1377
breeding flowers 894-898
breeding forage legumes 10J3-1018
breeding ornamental plants... 983-998
breeding peaches ... 690-696
breeding pears .... 026-627
breeding plums 715-717
breeding potatoes 428-434
breeding radishes .316-319
breeding rutabagas.. 313-316
breeding salad crops ...337-339
breeding soybeans 1180
breeding strawberries . . 473-482
breeding sweetcorn 390-392
breeding turnips .. 313-316
forest-tree improvement 1255-1257, 1263-1266
potato improvement. F. J . Stevenson and
C. V. Clark _ 405-444
of—
citrus, status of research 791-794
dog, status of research 1318-1321
fox, status of research . ... 1390-1394
milk goat, status of research 1310-1312
onion, status o f research 248-249
popcorn, similarity to condition in corn... 404
root vegetables, status of research.. 313-322
tomatoes, peppers, and eggplant, and their
improvement. Victor R. Boswell 176-203
recent developments 1469-1473
second-generation hybrids 1422-1432
Georgia Agricultural Experiment Station, Ex-
periment, Ga., peach and nectarine breeding
material available 700
Germ plasm-
flower, changing by artificial methods 913-915
sources for various grasses ... 1032-1038
superior, in strawberries .. 470-473
survey, of Angora goats ... 1287-1288
survey of milk goats. .. 1302-1303
Germany —
alfalfa breeding. . 1149
blaekborry-raspberry hybridization work... 508
clover breeders, list 1214
forest-tree improvement 1263-1278
fruit-breed ing stations 003-604
grape breeding 651
soybean workers, list 1185
strawberry —
breeding 469-470
varieties of importance. 454
vegetable breeding and improvement. 375
Gii.let, Felix, pioneer in filbert breeding 839
Gladiolus, breeding possibilities 942-945
Glycine wmj. See Soybean.
Goat —
agencies, sponsor ing breed improvement. 1285-1286
as a milk producer 1294-1302
breeders, future possibilities and needs. . 1308-1310
breeding-
superior germ plasm needs 1281
work of experiment stations 157
crossing with sheep, experiments 1289
Goats-
Angora—
article on, summary 159
breeding for improvement 1285
breeding, improvementpossibilities... 1290-1292
breeding problems. W. V. Lambert.. 1280-1293
distribution from Asia Minor 1281-1282
genetics and fleece studies 1288-1289
germ-plasm survey 1287-1288
industry in United States 1282-1286
research, Federal and State 1286-1289
breeding early, effects on milk secretion.. 1301-1302
domestication, history 1280-1281
milk-
article on. summary 160-161
Goats— Continued. Page
milk— continued.
breeders, organizations 1308
breeding, survey _ 1294
breeds in XJnited States 1295-1299
distribution in United States and
world 1299-1300
genetics 1310-1312
germ-plasm survey _ _ 1302
improvement. V. L. Simmons and \\\
V.Lambert 1294-1313
improvement needs 1309-1310
improvement, research and practices. . 1302-1310
Goodspeed, T. H., pioneer in flower breeding 913
Gooseberries—
and currants, improvement. George M.
Darrow 534-544
article on, summary 136-137
breeding-
Department of Agriculture 543
experiment stations.. _ 541-544
in foreign countries... 543-544
material... 538-540
English introductions, lisl _ 544
relation to white-pine blister rust 536-537
species, distribution _ 540
systematic breeding work 540-544
Goumi, breeding possibilities . 551-553
Grain Futures Act of 1922, amendment. . . 106-107
Grains-
breeding, for bunt resistance 90-92
feed —
production, 1934-36 _ _ 62
supply, effect of drought 33
seeds, shortage, situation, discussion by
Soeretary '_ 39-40
Granary, normal, purpose of crop insurance,
discussion by Secretary... _ 47-48
Grape-
blossoms, structure, description 639-640
breeders, United States, list 655
breeding-
achievements and need 653
and investigators conducting work, loca-
tion.. 655
Department of Agriculture 600-664
different varieties, objectives 614-645,
646, 048-649
experiment stations 656-660
in foreign countries 650-653
present status in United States..,. _ . 642-649
technique 639-641
development and improvement. Elmer
Snyder 631-664
direct-producing varieties, available for
breeding work 664
inheritance studies 653-655
rooistock varieties, available for breoding
work. _ 664
species, qualities for breeding, list. .. 634-635
varieties, introduction by-
Georgia Experiment Station, list. 656
New York State Agricultural Experiment
Station, list 668
South Dakota Agricultural Experiment
Station, list 659
vinifera—
development.. 646-649
varieties available for breeding 062-664
Grapefruit-
bud mutations.- 825
chromosomes, number 815
crossing with other citrus.. __ _ 798
improvement 775-779
industry, development in Puerto Rico 757
introduction by Department of Agriculture. 816
production and value in United States, 1934. . 751
See also Citrus fruit; Pummelo.
Grapes-
American native —
development and early improvement- . 633-639
parentage and origin, list 638-639
article on, summary 141-142
distribution and history 631-639
early improvement in Europe 649-650
European, development 646-649
1488
INDEX
Grapes— Continued. Page
hybridization —
methods.. Ml
possibilities 032
Muscadine, development 645-640
native bunch, development 042-045
Old World, introduction 632-033
Grass-
hybrids —
intergencric, list 1091-1093
interspecific, nature and characteristics, list. 1089-
1090
self-fertility, variation 1007
seed, yield and viability, increases.. 1048
Grasses-
adaptability to wet or saline soils.. 1050
aggressiveness, regulation by breeding... J048-1049
breeders, list 1081-1093
breeding-
importance 1045-1046
material available 1055
objectives and results 1051-1059, 1081-1093
possibilities and problems 1046-1050
selective, in United States and Canada... 1051-
1055
stations, foreign location 1055-1050
status in United States 1034
United States and Canada 1081-1088
character inheritance. 1074
chromosome numbers.-. 1067-1069, 1094-1099
compatibility, factor in hybridization 1009
defoliation, increased growth and vigor after. 1049
disease-resistant strains, production 1048
emasculation, methods and equipment- 1070-1072
flowering habits, description 1062-1064
forage, climatic adaptation in United
States 1038-1045
genetics and hybridization, technique.- 1001-1074
hybridization-
degrees of compatibility 1069
isolation methods and materials 1073
progress 1056-1060
technique 1009-1073
improved strains, development by selec-
tion. _. 1052-1054
inbreeding effects, relation to self-fertil-
ity 1064-1067
investigations . 92-93
miscellaneous-
article on, summary 151-152
breeding. II. N. Vinall and M. A.
Hcin 1032-1102
nativoshort, improvement 1044
nutritive value, importance 1050
palatibility, importance 1050
pasture, longevity studies 1049-1050
pollination studies. 1072-1073
self-fertility, relation to effect of inbreed-
ing _. 1064-1067
turf, quality, durability, and uniformity 1050
useful in breeding, world development cen-
ters 1034-1038, 1077-1080
various, germ-plasm sources 1032-1038
See also tinder specific kind.
Graves, Arthvk H., recommendations on
forest improvement 1204
Great Britain, forest-tree improvement 1278
Great Plains Horticultural Field Station at
Cheyenne, Wyo., vegetable breeding 123, 174
Griffiths, David, pioneer in lily breeding.. . 951,
952,953,955
Grimm, Wendelin, pioneer in alfalfa breed-
ing 1125, 1127, 1150
Groundcherry, breeding activities of State and
Federal agencies 368
Guar, status in United States 1006
Hambidge, Gove: What the Hook Is About. 119-170
Hart, E. H., pioneer in citrus introduction... 753
Hatch, A. T., pioneer in almond breeding.. 866-867
Hawaii-
Agricultural Experiment Station, citrus
breeding 800
citrus industry 757
Hay— Page
alfalfa, acreage, 1929 1122-1123
varieties, improved, distribution 1113-1114
Hays, Wiij.et M., pioneer in timothy breed-
ing _ _. 1104-1105
Heimburger, C, recommendations on forest
improvement- ._ 1264-1205
Hein, M. A.: Breeding Miscellaneous
Grasses. With H. X. Vinall... _. 1032-1102
Hemerocallis spp., breeding possibilities 945-947
Heredity-
fundamentals- -
discussion 106-107
for breeders. E. NT. Brossmau ]4iy-]449
in the dog. W. M. Dawson 1314-1349
See a/so Inheritance.
Hickories —
article on, summary 148
hybridization 854-856
miscellaneous, improvement- __ 852-850
Hickory —
breeders, list 885,886-887
breeding, problems and possibilities 855-857
varieties, improvement 844-850
ITicoria pecan. See Pecan.
Hippeastrum, breeding, possibilities 922-926
Hogs, adjustment under Agricultural Adjust-
ment Act, discussion by Secretary 10
Hor.i.owELi., E. A.: Clover Improvement.
With A. J. Pieters 1190-1214
Home Economics, Bureau of, research work. 102-106
Honeybee. See Bee.
Hoosac Mills case, decision of Supreme Court. 01
Hop-
breeders, list 1240-1241
breeding-
experiment stations _ 157
objectives and progress 1228-1230
possibilities 1217
problems and peculiarities 1218-1221
program, possibilities 1238-1239
recent 1223-1239
varieties —
and seedlings, physical and chemical
analyses 1229
characteristics 1228-1231
yards, variety testing progress 1223, 1225-1228
Hopkins, A. ])., pioneer in timothy breeding. 1105
Hops-
acreage and yield, 1935. 1217,1218-1219
article on, summary ... 156-157
brewing requirements, yield, and maturity.. 1218-
1220
chromosomes, numbers _ 1238
commercial varieties 1218-1219
countries producing 1216-1217
diseases of. _ 1219-1220
downy mildew —
prevalence and losses 1219-1220
records 1232
history _ 1215-1218
hybridization work 1221
improvement —
experiment stations 1222
in foreign countries 1222-1223, 1232, 1235-1238
survey summary, Willamette Valley,
Oreg., 1934-35. _ 1233
insects injurious to 1220
introduction by Department of Agricul-
ture 1221,1224
pollination work... 1234
quality characters 1220
seasonal productivity 1233-1234
seedlings, soft-resin contents 1235
use in beer making 1215-1216
varietal improvement—
D.C.Smith 1215-1241
experiment stations and workers 1240-1241
varieties-
development _ 1221-1223
important in United States 1221
yields, 1934-35 1233-1234
vegetative characters, constancy 1234
Horsebean, inheritance studies _ 1017
Uumulus spp. See Hop; Hops.
INDEX
1489
Page
Hybrid vigor, explanation 1421-1422
Hybridization. See undor specific crop.
Hybrids-
first generation, vigor 1421-1422
socond generation, inheritance in 1422-J432
Imports, competitive, significance discussion
by Secretary 28-29
Income —
consumer's, relation to farm prices, discus-
sion by Secretary 0-7
farm, relation to buying power, discussion by
Secretary 3-7
India, grasses useful in breeding _ __ 1036, 1078
Industrial production, comparision with agri-
cultural production 3
Inheritance —
characters in —
Adzukibean. 1017
alfalfa 1132-1133,1140-1147
Angora goats 1287-128!)
apple and pear, tree and fruit 691-592
apricots 743
bee, dominance and recossivencss., 1415
beets .... 319-321
celery 338-339
cherries... 734-736
citrus 791-794,799-803
clover 1208-1211,1213
cucumber.. 228
cucurbits 227-231
dog 1315-1349
ducks... 1377
eggplant 202-203
flowers 915-922
foxes.. 1388-1394
Fmgaria, peculiarities 481-482
grapes ... 053-055
grasses 1074
legumes 1013-1018
lettuce .. 338
milkgoats 1302,1310-1312
muskmelons _ 228-229
nut-producing species 879-881
peach 690-096
pear 585-589,626-627
peas 1427-1428
peppers 200-202
pigeonpea 1018
plums 715-717
potatoes 433,434,440-443
pumpkin 229-231
radish 317
red clover 1208-1209
rutabagas 314-315
soybeans 1169-1180,1186
squash 229-231
strawberries 470-474, 480, 48 1-482
sweet corn 390-392
sweetclover ._ 1210
tomato 194-197
turnip 314
velvctbean 1017
watermelon 229
white clover 1209
color in bees 1407,1409-1415
dominant characters, effects 1425-1426
linkage and crossing over 1432-1440
ratios, modifications 1428-1430
ratios, progeny with more than one pair of
genes 1427-1428
second-generation hybrids ... _ 1422-1432
See also Heredity; and under specific crop or
class of livestock.
Insect pests, control studies 65-67, 69-71
Insurance, crop. See Crop insurance,
lntermountain Forest and Range Experiment
Station, forest -tree improvement — . 1269
Introductions. See under spocific crop or
class of livestock.
Iris, breeding passibilities . ..... 917-950
Italy, grape-breeding work . — .651-652
Jaogeh, T. C: breeding and Improvement
Cucurbits. "WithT. W. Whiluker
Japan —
soybean wTorkers, list
vegetable breeding and improvement wor
Jenkix, T. J., pioneer in grass breeding
1050, 1060. 1007, 1009-1
Johnson grass, introduction and adaptation.
Page
-231
.. 1185
k. 375
.. 1055-
070, 1074
.. 1041-
1042
233-250
837-839
.Tones, II. A.: Onion Improvement
Jonks, J. I\, pioneer in filbert breeding..
Jvglant spp. See Walnut; Walnuts.
Kaki, T. ¥,., recommendations on forest im-
provement 1265
Kale--
breeding, State and Federal agencies 309
improved variety, development by State
and Federal research agencies 343
research results.. ._ 283, 289, 292, 293, 294, 295, 298
Kearney, T. H., tribute to Dr. Ooville 500
Kidneyvefch, status in United States 1006
KtitK, L. K, pioneer in sweetclover breeding. 1204,
1206
Kkox, Oiiakles \V.: The Breeding of Turkeys.
With Stanley J. Mursden . 1350-1360
Kohlrabi—
breeding and improvement in foreign coun-
tries . 375
research work, results. 283,292,294,290
Kudzu-bean, improvement, possibility 1006
Kumquat —
chromosomes, number 815
varieties, introduction __ 782
Lake States Forest Experiment Station, forest-
tree improvement 1266.1270
Lamhekt, W. V. —
Breeding Problems with Angora floats.. 1280-1293
Improvement of Milk floats. Willi V. L.
Simmons 1294-1313
Land-
tenure, practices in United States, discussion
by Secretary 25-26
utilization, policy, discussion by Secretary.. 22-27
Larkspur, chromosome numbers .. .. . 919,922
Late blight—
of potatoes, losses to grower. 400,408-409
resistance, development i n potato hybrids.. 418,
419-421
Lathyrus odoratus, breeding, possibilities.. .. 974-977
Lee, A. K.: Duck Breeding.. .. .... 1367-1378
Legumes-
articles on, summary 150-151
breeding possibilities 999-1018
chromosome numbers, list 1019-1027
cover crop, and miscellaneous forage. Holand
McKeeand A. J. Fioters . 999-1031
genetic studies . 1013-1018
miscellaneous, inheritance studies 1013-1018
value 1000
Leland Stanford Junior University, Palo Alio,
Calif.—
production and testing of apricot hybrids . 745-746
production and testing of plum hybrids. .. 720-721
Lemon —
bud mutations 824-825
chromosomes, number _. ... 815
crossing with lime, results 798
introduction by Department of Agriculture. 818
production and valuein United States, 1934. 751
varieties, introduction and improvement ... 780-782
See also Citrus fruit. .
Tjespedeza, improvement, possibilities... . 1000-1008
Lettuce-
article on, summary 130,131
broeding —
and improvement in foreign countries 372,
374, 375, 376
in United Slates . 332-334
State and Federal agencies. 332-
331,343, 352, 305, 300, 367, 368, 37()
history and value. 327,329-332
importance in United States . 327-334
1490
INDEX
Lettuce— Continued. 1 a8c
improved varieties, development by State
and Federal research agencies 342, 343
inheritance studies 338
types and adaptation _. 328-329
varieties-
description and introduction- 329-332
strains, and breeding lines, in cultures of
State and Federal research agencies.-- 351, 352
Lilies, chromosome numbers _ 917-918,922
IMium spp., classification 950,978
Lily-
breeding—
possibilities 950-955
supplementary data 978-983
hybrids, list 978-983
species, classification 950,978
Lime —
bud mutations 825
chromosomes, number _ 815
crossing with lemon, results 798
industry in Florida.-- 781
introduction by Department of Agriculture. 818
production and value in United States, 1934. 751
See also Citrus fruit.
Livestock —
situation —
1934-30, discussion by Secretary. 52-54
discussion by Secretary 80-85
See also Animals; and under specific name.
Livingston, A. W., introduction of new to-
mato varieties 123, 179-180,181
Loans, farm, type of and financing, discussion
by Secretary 59
Loganberry. See Blackberry, Logan.
Lotus, status in United States 1008-1009
Louisiana, sweet-orange industry 775
Lucerne. See Alfalfa.
Lumsden, D . V.: Improvement of Flowers by
Breeding. With S. L. Emsweller, Philip
Brierly, and F. L. Mulford 890-998
Lupine-
development, objectives 1009-1010
inheritance studies.. 101(1
Lupulin, use 1215
Magness, J. K —
Progress in Apple Improvement 575-014
Progress in Pear Improvement 615-630
Vegetative Reproduction. 1450-1456
Magruder, Roy: Improvement in the Leafy
Cruciferous Vegetables _•_ 283-299
Malaya-
citrus improvement 790
subtropical and tropical fruit-breeding sta-
tions, workers, and work _ 812-813
Manchuria, soybean workers, list 1185
Maple trees, breeding possibilities 545-546
Marketing agreements, discussion by Secre-
tary 61-65
Maksuen, Stanley J . : The Breeding of Tur-
keys. With Charles W.Knox 1350-1366
Marten, reproductive cycle 1381-1382
Mallhiola incana. See Stock, double-flowered.
McAkdle, Richard E., recommendations on
forest improvement _ 1265
McConkev, O., pioneer breeder of grasses 1054
McKee, Roland: Miscellaneous Forago and
Cover Crop Legumes. WithA.J.Pieters. 999-1031
Medicago—
saliva. See Alfalfa,
spp., improvement, possibilities 1003
Mediterrean region, grasses useful in breeding. 1034-
1035, 1077
Meibomia spp., improvement, possibilities 1000
Melilotus spp. See Sweetclover.
Melon-
breeding for resistance to powdery mildow_ 209,
218-220
Honey Dew, improved variety, development
by Stae and Federal research agencies 340
See alsot Cantaloup; Muskmel on; Water-
melon.
Mexico —
citrus improvement— 788
subtropical and tropical fruit-breeding sta-
tions and work... 814
vegetable breeding and improvement 376
Milk, of goats— Page
palatability and value 1295
physiology of secretion, studies. 1301-1302
properties and uses __ 1300-1301.
Milkweed, breeding possibilities 5(5
Mink farming, experiments 1380
Minnesota Agricultural Experiment Station,
plum introductions 719-720
Minnesota, University of, plum varieties of use
Inbreeding 718-719
Mohair production, statistics, 1920-35 1284
Morocco-
apricot breeding 743,741
peach breeding 087-688
Morris, Robert Tutti.e, pioneer in nut
breeding 853-854
Morse, W. J.: Improvement in Soybeans.
With J. L. Cartler 1154-1189
Mortgages, debt, farm , discussion by Secretary. 58-59
Mulford, F. L.: Improvement of Flowers by
Breeding. With S. L. Emsweller, Philip
Brierly, and D. V. Lumsden 890-998
Munson, Thomas Voi.xey, pioneer in grapo
breeding.. 037-038
Muskmelon —
breeding—
and improvement, history 213-220
and improvement in foreign countries. . 372, 370
for disease resistance 209,218-220
States and Federal agencies 357,
358, 307, 308, 370
improved variety, development by State
and Federal research agencies. _ _ _ 347
inheritance studies 228-229
varietal improvement and breeding 214-218
varieties, strains, and breeding lines, in
cultures of State and Federal research
agencies 355,357,358
See also Cantaloup; Melon.
Mustard, breeding and improvement in
foreign countries 375
Mutation-
bud, selection methods of improvement in
applo breeding 580-581
importance in potato improvement 409-411
Napier grass, climatic adaptation.-- 1042
Nasturtium, breeding possibilities... __ 955-958
National Park Service, land-utilization proj-
ects 23
Nectarine-
breeding material available 097-702
relation to peach 075
varieties of importance to breeders. 097-702
Netherlands—
red-clover breeding __ 1214
strawberry varieties of importance 454
New Jersoy Agricultural Experiment Station,
New Brunswick, N . J ., peach and nectarine
breeding material available... 700-702
New Mexico Agricultural Experiment Station,
milk-goat breeding, research 100, 1305-1308
New South Wales, apricot breeding 743, 744
New York Agricultural Experiment Station,
Geneva, N. Y., cherry varieties in use by... 737
New York Botanical Garden, forest-tree im-
provement 1249,1270-1277
New York State College of Forestry, forest-tree
improvement 1270
New York State Conservation Department,
forest-tree improvement. 1270
New York State Experiment Station, intro-
duction of new pear varieties 628
New Zealand —
citrus improvement 790
strawberry varieties of importance ... 454
subtropical and tropical fruit-breeding sta-
tions, workers, and work 814
Nolan, W.J. : Bee Breeding __ 1390-1418
North Africa —
citrus improvement __ 789
subtropical and tropical fruit-breeding sta-
tions, wrorkers, and work 812
North America —
grasses useful in breeding 1037-1038, 1078-1080
pear growing, development 616-025
INDEX
1191
Pago
Northeastern Forest Experiment Station,
forest-tree improvement ] 270-1271
Northern Kocky Mountain Forest and Kange
Experiment Station, forest-tree improve-
ment- 121-1,1271-1273
Norway —
clover breeding 1214
strawberry varieties of importance _ 4M
vegetable breeding and improvement. 378
Nut-
breeders, in United States, list 881-889
breeding—
H. L. Orane, C. A. Heed, and M. N.
Wood 827-889
experiment stations — 117-119
fundamentals .. 871-881
stations in United States, list 881-88<i
varieties of value 886-889
producing plants-
character inheritance .. .. 879-88 1
fertilisation of ovule and embryo develop-
ment 877-878
incompatibility, factors affecting 838-879
somatic chromosome n umbers in, list 884
stigma receptivity, pollen shedding, and
pollon viability . 875-877
varieties of value for breeding 880-889
Nuts-
article on, summary _ 147-149
native, improvement 852-858
Okra—
breeding activities of State and Federal
agencies 366,369
varieties, strains, and breeding lines, in cul- 4
tures of State and Federal research agen-
cies 3(12
Olive, farm value, 1934-35 751
Onion- —
breeding —
and improvement in foreign countries. . . 372, 374
for resistance to disease 242-244
for resistance to thrips 244-245
for resistant varieties, possibilities 234
State and Federal agencies 305, 366, 367, 369
commercial varieties, introduction 236-237
cytology and genetics 248-249
improved varieties, development by State
and P'cderal research agencies 349
improvement. H.A.Jones 233-250
origin, culture, and uses 233-235
premature seeding and freezing injury 247
varietal adaptation .. . 235-236
varietal improvement 237-242
varieties, strains, and breeding lines, in cul-
tures of State and Federal research agen-
cies - 362-363
Onions-
article on, summary _ 125-120
crossing between species 245-247
Orange—
mandarin-
crossing with other citrus, results 797-79S
improvement 779-780
introduction by Department of Agricul-
ture - 817
typo, introduction 754-755
navel, improvement 770-772
Satsuma —
chromosomes, number 815
introduction by Department of Agricul-
ture 817
variety improvement— 779-780
sour, introduction by Department of Agri-
culture - 816
sweet —
bud mutations 821
chromosomes, numbers 792,815
growing in Hawaii -- 757
improvement-— 766-775
introduction by Department of Agricul-
ture 816-817
tangerine-
bud mutations - 825
chromosomes, number 815
variety improvement 779
Orange— Continued. ' aSe
trifoliate- -continued.
chromosomes, number 815
crossing with Cilrns and Fortunclla
species .. .._ _ 708-799
Washington Navel, development. 771-772
See also Citrus fruit.
Oranges —
growing in Philippines 757-758
production and value in United States, 1934 751
production in Puerto Uieo ... 757
Ornamentals, genetics 983-998
Oxford Paper Co., forest -tree improvement. . 1249,
1262, 1276-1277
Pacific Northwest Forest Experiment Sta-
tion, forest-lree improvement 1244, 1273
Palo Alto, Calif., production and testing of
plum hybrids 720-721
Para grass, climatic adaptation KU2
Parsnip —
breeding and improvement in foreign coun-
tries— 374
history and present status :)|)8
Parthenogenesis, in strawberry, value to
breeder _ 482
Pasture, investigations 92-93
Pea-
breeders, work 253-260
breeding—
and improvement in foreign countries 372,
374, 375, 376, 377
at experiment stations. .... . .. 258,259
State and Federal agencies . 259, 365, 366. 368, 370
characters, heritable, ratios with more than
one pair of genes . II 27-1 428
disease resistance, genetics of. ... 272
field, improvement, possibilities— _ ._ ... 1005
garden, English varieties, superiority 171, 172
genetics, research _. . 268-273
grass, status in United States — 1006
improved varieties, development by State
and Federal research agencies. . . 344
improvement work __ 251-260
Progress, description and value 252, 25-1
varieties —
and strains, in cultures of State and Fed-
eral research agencies .. _ 353
and strains, new, origin and evaluation . 258-260
current, characteristics and origin . 254-257
forcanning 255-257
misnaming _ _ ... 255
oilier, origin 253-251
See aim Peas.
Peach-
blossoms, bagging precautions — . 670
breeders, private, and varieties originated
by - 678-681
breeding—
and breeders in United States and
Canada - ... - 696-697
at experiment stations . ._ .— 681-685
in foreign countries. — 686-088
in United States (178-686
material available. 697-702
objectives 088-690
characters, inheritance 600-696
chromosome numbers 690
commercial-
requirements 678
varieties, qualities 676-677
distribution 673
early history 673-675
Elberta, origin and development. _ 666
flower structure 068
genetics, contributions to 690-096
growing commercially, effect on variety
improvement — 675-678
hybridization 680-687
introduction and improvement. 673-702
pollen sterility, frequency.. . 695-696
race groups and description. 673-675
varietal improvement 680-087, 688-690
varieties—
commercial, in United States 676-67 1
development and introduction by public
institutions -- G82
1492
INDEX
Peach— Continued. Page
varieties — continued .
improvement by breeding, objectives. . _ 688-690
of importance to breeders 097-702
of use to breeders 679-881
Peaches-
article on, summary 142
commercial production 665
dried, commercial production.- 605
Peanut-
breeding—
and improvement in foreign countries 372
State and Federal agencies 363-305,309
improved variety, development by State
and Federal research agencies 349
improvement, possibilities 1010
varieties, strains, and breeding lines, in cul-
tures of State and Federal research agencies. 363
Pear-
blight, menace to eastern pear growing... 616-617
breeders, list 628
breeding—
at experiment stations 620-623, 628
by Department of Agriculture, 623-624
material, availability 619-620,629-630
objectives.- 618-619
present status in United States 620-625
chromosome numbers 585-589, 626-627
cytology and genetics... 626-627
early history 015-616
growing in North America, development.. 616-625
hybridization technique 581-591
improvement, progress. J. K. Magness.. 615-639
seeds, handling for hybridization 583-585
tree and fruit, character inheritance 591-592
varieties-
introduction by New York (State) Experi-
ment Station 628
introduction from China and Kussia 617
leading, list 627-028
Pears, article on, summary 140-141
Peas—
and beans, breeding and improvement. B.
L. Wade 251-282
article on, summary 127,128
classification by use 252
freezing and canning _•___ 252-253
history 251
world production 261-252
See also Pea.
Pecan-
breeders, list 885,887-888
breeding-
history in United States 846-849
problems... 849-851
status and aims 851-852
improvement 845-852
Pecans, article on, summary 148
Pepper-
breeding, State and Federal ageneies. 365, 366, 367
improved varieties, development by State
and Federal research agencies 349
improvement in United States 188-192
inheritance studies 200-202
varieties-
description 189-192
introduction and breeding 193-194
variety, strain, and breeding lines, in cul-
tures of State and Federal research agencies 354
Peppers-
article on, summary 124
history and value 187-188
improvement and genetics. Victor R. Bos-
well 187-192,200-202
Phaseolus—
crossing technique and interspecific hybrid-
ization 276
genetic factors _ 273-275
linkage and cytology 276-277
lunatus. See Beans, lima.
See also Bean; Beans.
Philippine Islands-
citrus industry 757-758
polyembryony in citrus _ 794
Phleum pratense. See Timothy.
Physalis. See Groundcherry.
Page
PlETEIiS, A. J —
Clover Improvement. With E. A. Hollo-
well 1190-1214
Miscellaneous Forage and Cover Crop Le-
gumes. With KolandMeKee... 999-1031
Pigeonpea—
inheritance studies _ mis
introduction and improvement 1010
Pinus spp., seed origin studies.. 1244-1240, 1267-1279
Piper, Charles Vancouver, pioneer in soy-
bean breeding " 1155
Pistache, development, possibility 869-870
Pisum—
arvemc, improvement, possibilities 1005
genetic factors _ 269-272
history _ 251
linkage and cytology. 272-273
See also Pea; Peas.
Plant-
breeding, some unusual opportunities.
George M. Darrow and Guy E. Yerkes.. 545-558
cells, fertilization, process 1419-1420, 1421-1422
pests, control studies _ 67-69
research, discussion by Secretary 88-94
tissues, chromosome studies 1451-1 453
Plant Industry, Bureau of—
Division of Plant Exploration and Intro-
duction, introduction of disease-resistant
potato varieties 418,420
Division of Plant Exploration and Introduc-
tion, vegetable-breeding programs— __ 175
forest-tree hybridization 1266-1267
research work 88-94
Plants-
characters, second-generation combinations. 1424-
1425
dominant characters, inheritance 1425-1420
double-flowering, chromosome numbers, un-
usual, significance 919-922
genetic analysis, comparison with animal
genetics.. 1441-1449
ornamentals, genetics 983-998
segregation ratios 1424-1425
Plum-
breeders, private, and varieties originated
by 709-711
breeding—
in Canada- 715
material available at California Agricul-
tural Experiment Station, Da vis, Calif. 721-724
material for commercial varieties 703-708
methods .. 709
objectives 709
State and Federal stations 711-715
varieties in useat University of Minnesota. 718-71U
work and workers in United States and for-
eign countries 717
characters of interest to breeder 715-710
chromosomes, numbers 716-717
early history 703
genetics and cytology _ 715-717
hybridization progress 710-715
hybrids, production and testing in coopera-
tive breeding investigations, Palo Alto,
Calif 720-721
improvement 703-724
introduction into North America 703
species commercially important in America . 703-
708
sterility, genetic explanation 716
varieties —
incompatibility tests 716
introduction by Minnesota Agricultural
Experiment Station.. 719-720
introduction by New York Agricultural
Experiment Station 713
Plums —
article on, summary 142-143
commercial production 665
Pollen, handling for pear and apple hybridiza-
tion 583
Pollination-
control, importance in nut breeding 871-875
self, failure in blueberry improvement ex-
periments 501-562
INDEX
1493
Page
Polyploidy, importance In forest-tree breeding. 1260-
1261, 1265
Poncirus trifoliala. See Orange, trifoliate.
Poole, C. F.—
Improvement of Sweet Corn 379-394
Improving the Root Vegetables 300-325
Popcorn-
article on, summary.- 131-132
breeding-
Arthur M. Branson _ 395-404
for resistance to diseases and insects 403-404
methods and results 397-404
commercial varieties 396
distribution, varieties, and desirable quali-
ties 395-397
ear tests and factors affecting. ._ 397-398
early history 395
genetics and cytology, similarity to condi-
tionsincorn ... . — 404
hybridization 399-403
improvement by mass selection 397-399
inbreeding results 402-403
production . 395,396
synthetic varieties, production. 403
Potato -
botanical relationships.. 406-407
breeders, early, and varieties originated 438
breeding —
cooperative work, organization 414-416
for disease resistance 418-427
methods, advantages and limitations. . _ 428-430
methods, genetics, and cytology .. 428-434
program in United States 413-427,439
recent results 417-418
changes duo to mutation . 409-111
characters, genetic behavior, and investiga-
tors and reference numbers . . 434, 440-442
chromosomes, numbers. .. , 433, 142-443
(irons-pollination technique . 412-413
disease-resistant varieties, distribution by
Department. .- 425-427
diseases —
control 406,408-409
losses and problem 406
early history 405-406
early improvement in quality and yield- 407-408
flower, morphology and pollination... ._ ... 411
genetic studies 433
hybrids, resistance to late blight and toler-
ance to frost. 418,419-421
improvement-
breeding and genetics in. F. 3. Steven-
son and C. F. Clark 405-444
by asexual reproduction .. 409-411
by clonal selection 417
by sexual reproduction 411-413
inbreeding and recombination of selfed lines. 417
introduction into Europe and North Amer-
ica - 40.5-406
late blight, varieties resistant to 418, 419-421
lines and progenies of superior genetic char-
acters . .439-4-10
reproduction methods . 409-413
scab-
causal organism and losses to grower.. 409
varieties resistant to.. . — 421-424
species-
characters of breeding value ..... . 443-444
chromosome numbers... 433,442-443
sterility, handicap to breeders. . 430-433
susceptibility to-
late blight 406,408-109
virus diseases 408
varieties -
available, of value to breeders 438-439
resistant to late blight 419-121
resistant to scab -121-124
virus diseases, varieties resistant to.. - 418-419
Potatoes, article on, summary 132-133
Poultry industry, situation, discussion by
Secretary -- 57
Prairie grass, improvement 101!
Primrose, chromosome numbers 918-919
Pritciiaku, F. J ., tomato breeding 183-186
Progeny— Pago
baekcrossing, technique 1430-1432
characteristics, segregation 1422-1432
characters —
second generation, segregation ratios.. 1424-1425
segregation ratios, linkage effects 1435-1440
dominant characters, effects... 1425-1426
inheritance ratios-
modifications 1428-1430
with more than one pair of genes 1427-1428
Prunes, dried, commercial production 665
Prunvs —
arweniaca. See Apricot; Apricots.
domestka. See Plum; Prune.
perxica. See Peach.
Pseudostarchy, occurrence in sweet corn 391
Public Roads, llureau of, work _ 111-116
Puerto Rico, citrus industry 757
Pummelo—
introduction by Department of Agriculture, 810
varieties, introduction. ... 782
See also Grapefruit.
Pumpkin-
breeding and improvement—
in foreign countries... .. _. 372
investigations 224-227
inheritance studies 229-231
varietal improvement.. 225-227
Purchase power, relation to farm income, dis-
cussion by Secretary... ... 3-7
QrARNBERO, A. A., pioneer in filbert brood-
ing. 840
Quinces, oriental, breeding possibilities 553-555
Radish-
breeding—
and improvement in foreign countries 373
and improvement, possibilities .... 301
States and Federal agencies 367,370
genetic studies 316-319
Raspberries, article on, summary 135-130
Raspberry—
and blackberry improvement. George M.
Darrow 496-533
berries related to 511
black-
characteristics in America and Europe 510-511
early history .... 510
breeders, lis t 527-528, 530
breeding—
at experiment stations.. 511-513, 511-519, 527-528
by Department... 519
by private agencies 530
in foreign countries... 519-520
objectives 527-528
chromosome numbers 632-533
colors, varied, description 513-514
crossing, technique 522-523
early history and origin 609-510
overbearing, or fall-fruiting habil, descrip-
tion _. 621-522
fruit characters, superiority 531-532
generic crosses, fruitlessness 521
introduction and improvement 509-523
plant characters, superiority ... ... 531
qualities of value to breeders 511-513
red-
breeding possibilities 497
characteristics in America and Europe.. 510-511
early history 509-510
species, improvement possibilities 511-513
superior qualities-
list - 529-530
source 531-532
varieties originated by public agencies 529-530
variety crossing 511',, 518
wild black, source of cultivated black varie-
ties.. 510
wild red, source of cultivated red varieties. .. 510
Rasp berry-blackberry h y brids—
characteristics 504
growing in England and Germany — 508
value 516-517
Real cst.ate, farm, situation, discussion by
Secrelary 59-61
1494
INDEX
Page
Reasoner Bros., introduction of citrus fruit. 778,782
Redtop, climatic adaptation 1040-1041
Reed, C. A.: Nut Breeding. With II. L.
Crane and M. N. Wood 827-889
Reed canary grass, climatic adaption 1045
Reimer, F. C., pioneer in pear breeding 623
Reproduction, vegetative—
J. R. Magness 1450-1456
discussion _ _.. 167-168
Research-
agricultural, provisions under Bankhead-
Jones Act 37-38
projects, cooperative, discussion by Secre-
tary 110-113
Resettlement Administration, land-utilization
program 22,23,24,25-26
Resin contents, of hops 1235
Rhubarb-
breeding—
activities of Stale and Federal agencies. . . 367
and improvement in foreign countries. . 372, 373
varieties, strains, and breeding lines, in cul-
tures of State and Federal research
agencies 363
Riohter, F. I., recommendations on forest
improvement 1265-1206
Risien, E. E., pioneer in pecan breeding... 846-847
Road construction, discussion by Secretary. 114-116
Ropjnson, T. Ralph: Improvement of Sub-
tropical Fruit Crops: Citrus. With Hamil-
ton P. Traub 749-825
Rocky Mountain Forest and Range Experi-
ment Station, forest-tree improvement 1247,
1253, 1265, 1273-1274
Rogers, Edward Stanifohd, pioneer in grape
breeding 636
Root vegetables. See Vegetables, root.
Rosa, J. T., breeding of cucurbits 218-219
Rose, breeding possibilities 958-965
Roses, developed by Walter Van Fleet, list.- 961
Hubus, chromosome numbers 532-533
Rudolf, Paul O., recommendations on forest
improvement 1266
Russia. See Union of Soviet Socialist Repub-
lics.
Rutabaga —
breeding and improvement 302-303
chromosome number 302,303
genetic studies 313-316
X turnip hybrids, genetic studies 315-316
Rutaccae —
chromosome numbers of subtropical and
tropical fruit species and varieties 815
genera of interest to citrus breeder. 758, 760, 819-821
introduction by Department of Agricul-
ture 819-821
Sainfoin, improvement, possibilities. 1010
Salad-
crop plants-
genetics -. 337-339
improvement problems 326-327
crops-
article, on, summary 130-131
improvement. Ross C. Thompson 326-339
Salsify, history and present status 308
Saunders, William, introduction and propa-
gation of Washington Navel orange 771
Scab, potato varieties resistant to 421-424
Schreineu, Ernst J.: Improvement of Forest
Trees 1242-1279
Scotland-
strawberry varieties of importance 454
timothy-breeding projects 1121
vegetable breeding and improvement work. 375
Seed origin, studies of species, varieties, races,
and strains 1244-1246, 1254-1256, 1267-1279
Serradella, status in United States 1010
Sesbania, status in United States 1011
Shaddock, introduction by Department of
Agriculture 816
Shallot-
breeding, State and Federal agencies 366
improved varieties, development by State
and Federal research agencies 350
Page
Sheep-
crossing with goat, experiments 1289
situation, effect of drought 54
Simmons, V. L.: Improvement of Milk Goats.
With W. V. Lambert 1294-1313
Smith, D. C: Varietal Improvement in
Hops 1215-1241
Snapdragon, breeding, possibilities 965-969
Snyder, Elmer: Grape Development and
Improvement.. 661-664
Soja max. See Soybean.
Soil-
chemistry and physics, research work 75-77
conservation-
associations, projects 21-22
program, discussion by Secretary 14-22
depletion in South, discussion by Secretary. 13-14
erosion. See Erosion, soil.
losses from floods and dust storms.. _ 19-20
Soil Conservation Act of 1935, authorization
for research and demonstration. 12-13
Soil Conservation and Domestic Allotment
Act, provisions and policies 10, 11-12
Sotanum tuberosum. See Potato.
South Africa, subtropical and tropical fruit-
breeding stations, workers, and work 813
South America-
citrus improvement 788
grasses useful in breeding 1037,1078
subtropical and tropical fruit-breeding sta-
tions, workers, and work 814-815
Southern Forest Experiment Station, forest-
tree improvement 1252-1253, 1274-1275
Southwestern Forest and Range Experiment
Station, forest-tree improvement 1275
Soybean-
acreage, 1935 1156
breeders, list.. 1184-1185
breeding methods 1164-1169
characters, linkage 1186
chromosomes and genes, identification ] ISO
classification by seed characters 1175
crossing, natural and artificial... 1165-1167
development, possibilities _. 1156
disease resistance 1179
distribution 1156-1157
genes, list — 1185-1186
genetics liso
history 1154-1156
hybrid vigor 1169
improvement. W. J. Morse and J. I,.
Cartter 1154-1189
inheritance and cytology 1169-1180
mutations 1168
oil, production 1159-1160
plant characters, inheritance 1169-1174
pollination technique l]67
products, commercial uses 1160
seed characters—
by varieties 1187-1189
inheritance 1175-1179
utilization 1159-1160
varietal-
adaptation... net
improvement 11C1-11R3
varieties, origin and characteristics 1187-1189
workers, list 1184-1185
world production 1156-1157
Soybeans, article on, summary 154-155
Spinach —
breeding—
and improvement in foreign countries 377
State and Federal agencies 365,366,369
improved varieties, development by State
and Federal research agencies 342,343
Squash-
breeding —
and improvement in foreign countries 372
and improvement investigations 224-227
State and Federal agencies 347,
358, 365, 366, 368, 369
bush, improved variety, development by
State and Federal research agencies 346
inheritance studies. 229-231
INDEX
I19S
Squash— Continued. IaSe
varietal improvement 225-22"
varieties, strains, and breeding lines, in cul-
tures of State and Federal research agen-
cies 353-356, 357, 358
Standards, Federal, use and improvements. 100-102
Stevenson, F. J.: Breeding and Genetics in
Potato Improvement. With C. F. Clark. 405-444
Slizolobium spp. See Velvetbean.
Stock—
double-flowered, breeding, possibilities 969-973
double-flowered, chromosome numbers, un-
usual, significance 919-922
Strawberries, article on, summary 133-134
Strawberry —
breeders —
in United States _ 403,490-491
private, and varieties originated by. 403. 490-493
breeding —
at experiment stations. 403,404,405-409,486-489
by Department of Agriculture 440
for improved varieties 405-470
for superior qualities 470-473,487-489
in United States 401-469
methods _ 402-403
objectives .... 461
technique 457-461
bud selection, infrequency of sports 482
chromosomes —
numbers 472,473-480
variability 478-479
commercial development 445-446
distribution 445-446
early history 446-451
everbearing variety, description 454
flower, types, description ... 455-457
generic crosses, results 480-481
genetics and cytology — 473-482
germ plasm, superiority, inheritance 470-473
growing from seed 454-455
hybridization-
methods 457-460
work 448-450
hybrids, crossing between chromosome
groups 479-480
improvement—
George M. narrow .... 445-495
early eilorts 446-401
inheritance in —
peculiarities -. 481-482
species with seven pairs of chromosomes . 480
parthenogenesis, value to breeder 482
perfect-flowered varieties, partial sterility. 456-457
pollination methods 457-460
qualities, superior, sources 494-495
seedlings, selection '460-461
species, of world 474-478
varieties —
American and European, origin 450-451
important, in foreign countries 453-454
important, in United States 451-453
originated by private breeders 463, 490-492
originated by public agencies 487-489
superior qualities 472-473,494-495
wild, selection, by Indians 447
Stubtevant, Grace, pioneeriniris breeding. 948-949
Sudan grass, climatic adaptation 1045
Sugar beets, pollination technique 31 1
Sulla, status, United States and foreign coun-
tries 1011
Summary of articles. GoveHambidge 119-170
Surpluses, removal under marketing-agree-
ment programs 62-63
Sweden —
alfalfa breeders, list 1149
clover breeders, list 1214
fruit-breeding stations 604
timothy-breeding projects 1121
vegetable breeding and improvement work. 377
Sweet pea, breeding, possibilities 974-977
Sweetclover—
breeding—
abroad.. 1207
in North America 1206-1207
Sweetclover— Continued. Page
characteristics and distribution 1203-1204
genetics and cytology 1210
hybridization. 1206-1207
improvement 1203-1208
interspecific hybridization _. 1210-1211
pollination and fertility 1207-1208
varieties, history 1204-1200
Sweetpotato—
breeding—
and improvement in foreign countries.. 372
State and Federal agencies 350,
364, 365, 360, 368, 369, 371
improved varieties, development by State
and Federal research agencies... 350
varieties, strains, and breeding lines, in cul-
tures of State and Federal research agen-
cies..
383-364
Switzerland —
forest-tree improvement 1279
red-clover breeding 1214
Taber, G. L., introduction of citrus fruit. . 782, 785
Tangerine. See Orange, tangerine.
Tariff, concessions by United States, discus-
sion by Secretary _ 30-31
Taro—
history and introduction of new varieties. 307-308
pollination technique 311-312
Tasmania, strawberry varieties of importance. 454
Taxes, farm real estate, situation, discussion by
Secretary _ 59-61
Tennessee Valley Authority, forest-tree im-
provement 1251-1252,1275
Terriers, color, weight, and uses, list 1347-1348
Texas-
Agricultural Experiment Station-
citrus breeding 805-806
goat breeding 1286-1288
grapefruit varieties, improvement 778-779
sweet-orange varieties, improvement 774-775
Thompson, Ross C: Improvement of Salad
Crops 326-339
Tlirips, control by breeding resistant onion
strains J 244-245
Timothy-
acreage 1103
article on, summary 152-153
breeding-
objectives 1107-1115
projects 1120-1121
work 1114-1115
cross pollination 1109-1111
history 1103-1104
improvement —
Morgan W. Evans 1103-1121
at experiment stations 1105-1106,
1114-1116,1120-1121
by Department of Agriculture 1105, 1106
history 1104-1107
in foreign countries 1107, 1115
introduction and adaptation 1039-1040
loafy-pasture varieties, development 1108-1109
qualities, value of single-plant selections 1110
rust-resistant strains, selection 1107-1108
variations, basis for improvement 1 109
varietal improvement 1107-1108, 1111, 1113
vfiripl, ip s^ —
development 1109-1111
improved, description 1111-1113
introduction 1118-1119
Tobacco-
adjustment under Agricultural Adjustment
Act, discussion by Secretary 10
situation, 1923-36, discussion by Secretary. . 55-56
Tobacco Inspection Act, provisions 99
Tomato —
breeding—
and improvement in foreign countries 373,
374, 375, 376, 378
State and Federal agencies.. 182-187,346,355,
365, 366, 367, 368, 369, 370, 371
chromosome behavior studies 197-198
cytology, studies 198-200
history and value 176-177
1496
INDEX
Tomato— Continued. Page
improved varieties, development by State
and Federal research agencies 344-346
improvement in United States, 1850-1910.. 178-181
inheritance studies 194-197
Stone, introduction 180
Trophy, introduction 179
varietal adaptation, review.. 177-178
varieties-
grown in Europe 171-172
introduced by public agencies 182-187
private introductions, 1910-36 181-182
strains, and breeding lines, in cultures of
State and Federal research agencies — 354-355
Tomatoes-
article on, summary 123-124
improvement and genetics. Victor K.
Boswcll- 170-187,194-200
Top-crossing, value in breeding sweet corn.. 387-388
Trade-
agreements, reciprocal, discussion by Secre-
tary 29^30
foreign, in farm products, discussion by
Secretary 27-31
Tjuub, Hamilton P.: Improvement of Sub-
tropical Fruit Crops: Citrus. With T.
Ralph Robinson 749-825
Tree-
breeding—
early work - i«»
need for and outlook 1243
recent accomplishments - - - 1249-1253
progeny, individual, tests.. .. 1246-1248,1254-1256,
i b 1207,1208-1270,1274
Trees-
forest —
article on, summary - 158-159
breeders - 1204-1260
breeding in Europe.... 1244, 1247, 1253, 1277-1279
breeding, need of developing technique... 1262-
breeding, time element 1259-1260
characters 1254-1255
chromosome numbers 1260-1261
fundamental investigations 1263-1206
hybridization 1248-
1253, 1256-1257, 1266-1267, 1269, 1274, 1275-1278
improvement. Ernst J. Schreiner — 1242-1279
improvement bibliography 1266
improvement phases 1244
improvement problem, approach 1254-1263
mass selection 1256-1258
mutations 1200-1261
pedigree breeding within and between
varieties, species, and genera 1258-1259
pollination control, technique 1255-1266
vegetative propagation 1253-
1254,1261-1262,1275
hybrids, natural, list 1248
improvement, through selective breeding
and hybridization. 1256-
1257, 1266-1267, 1269, 1274, 1275-1278
Trifolium spp. See Clover.
Tropaeolum spp., breeding, possibilities 955-958
Truck crops, production, effect of drought,
1934-36 - 56
Tung tree-
breeders, list - 885
development 870
Turkey —
blackhead disease of, control 1351, 1353-1354
breeding— . ,„„,„„
bv experiment stations 162,163
needs... 1350-1352
past work 1359
relation to market trends 1359-1361
research - 1361-1365
Bronze, ogg quality studies 1363-1364
domestic, American varieties, description.—
1356-1358
industry, development, problems 1350
wild, North American, description 1355-1356
Turkeys— . ...
American, six standard varieties, weight and
color -,roViu%
article on, summary. — 102-103
Turkeys— Continued. 1 aK°
breeding. Stanley J. Marsden and Charles
W.Knox 1350-1366
modern, relation to wild ancestors 1354-1359
outbred, egg quality studies 1365
Turnip-
breeding and improvement 302-303
Bruce, varietal resistance to clubroot... 303
chromosome number 302,303
genetic studies 313-316
TurnipXrutabaga hybrids, genetic studies.. 3J5-316
Tysdai., n. M.: Alfalfa Improvement. With
H. h. Westover 1122-1153
Union of South Africa, vegetable breeding and
improvement 378
Union of Soviet Socialist Republics—
fruit-breeding stations ... 604
grape-breeding investigations 652-653
red-clover breeding 1214
vegetable breeding and improvement 378
United States-
alfalfa—
breeders, list 1127,1149
varietal improvement, summary 1150-1151
apple breeding 592-600,004-614
apricot broeding and workers 744
bee breeding 1402-1408,1417
cherry breeding and workers 730-733,730
clover breeders, list 1213
forest-tree breeding 1266-1277
grass breeding 1051-1055,1081-1087
nut-breeding stations, list 884-886
peach breeding 678-686,090-697
peach varieties grown commercially 676-677
plum breeding and workers 711-714, 717
rod-clover improvement 1193-1190
soybean workers, list 1184-1185
strawberry-
breeding 461-469
varieties of importance 451-453
subtropical and tropical fruit-breeding sta-
tions and workers 811-812
timothy-breeding projects 1120
vegetable breeding _ 365-371
United States Horticultural Station, Belts-
villo, Aid., peach and nectarine breeding
material available 697-698
United States Regional Vegetable Breeding
Laboratory, work 123,174
Vak Fleet, Walter, pioneer in rose breed-
ing 961-962
Vegetable—
breeding laboratory, provisions under Jones-
Bankhead Act 123, 174
crop breeding and improvement, introduc-
tion. Victor R. Boswell 171-175
crops-
articles on, summary 122-123
improved varieties and strains, develop,
ment by State and Federal research
agencies 341-351
improvement, appendix. Victor R. Bos-
well 340-378
improvement, new influences affecting... 174-175
oyster, history and present status - 308
strains, varieties, and breeding lines, in cul-
tures of State and Federal research agen-
cies., 350-364
varietal improvement agencies, work 173-174
Vegetables-
breeding—
and improvement in foreign countries.. 371-378
State and Federal agencies in United
States 365-371
foreign varieties, adoption in United
States 171-173
leafy cruciferous, improvement. Roy ila-
gruder 283-299
production, effect of drought 50
root-
article on, summary 129-130
breeding aspects.. 308-313
genetic studies 313-322
INDEX
1497
Vegetables— Continued. page
root — continued.
history and origin 300-301
hybridization 312-313
improvement. C.F.Poole 300-325
improvement, early methods 300-301
Vegetative-
propagation, relation to plant breeding.. 1454-1456
reproduction. J. R. Magness 1450-1456
Velvetbean—
improvement, possibilities 1011-1012
inheritance studies _. 1017
Vetch, improvement, possibilities _. 1012-1013
Vicia spp., improvement, possibilities 1012-1013
Victoria, strawberry varieties of importance.. 454
Vigna sinensis. See Cowpea.
Vinall, H. N.: Breeding Miscellaneous
Grasses. With M. A. Hein 1032-1102
Virus diseases-
immunity of potato hybrids to_._ 418-419
susceptibility of potato to _-_ 408
Vitamin production, inheritance in citrus.. 802-803
Volz, Charles J., pioneer grower of citrus... 750
Wade, B. L.: Breeding and Improvement of
Peas and Beans 251-282
Waite, M. D., pioneer in pear breeding 623-624
Wakeley, Philip C, recommendations on
forest improvement 1266
Wales-
alfalfa breeding _ 1149
clover breed 1214
timothy-breeding projects 1121
Wallace, Henry A., Secretary: Explanatory
Statement _ [118]
Walnut-
black—
breeders, list 885-886,888-889
improvement 857-859
breeding by Department of Agriculture 858-
859, 885-886
English. See Walnut, Persian.
Japanese-
breeders, list _ 886,889
improvement 859-860
Persian-
breeders, list 886,889
breeding, objectives 863-865
early history and distribution 861-863
hybridization 862-865
improvement 860-865
Walnuts— PaKe
article on, summary _ 148
improvement 857-865
Watermelon —
breeding —
and improvement in foreign countries 373
and improvement studies. 221-224
for wilt resistance 223-224
State and Federal agencies.. 347, 365, 368, 369, 371
improved varieties, development by State
and Federal research agencies 346,347
inheritance studies 229
varietal improvement '. 221-223
varieties, strains, and breeding lines, in cul-
tures of State and Federal research agen-
cies 356,357
See also Melon.
Watson, L. R., development of method of bee
breeding 1398, 1407
Weather —
conditions of 1936, discussion by Secretary.. 33-35
forecasting, new methods, discussion by
Secretary 36-37
Webber, Herbert J., pioneer breeder of
citrus. 787,794,797
Westover, H. L.: Alfalfa Improvement.
With H. M. Tysdal 1122-1153
Wheat-
adjustment under Agricultural Adjustment
Act, discussion by Secretary 10,11
chromosomes, number and behavior 1421
situation, 1935-37, discussion by Secretary.. 50-51
Wheatgrass, crested, introduction and climatic
adaptation _ _. 1042-1043
Wheatgrasses, climatic adaptation 1045
Whitaker,. T. W.: Breeding and Improve-
ment of Cucurbits. With I. C. Jagger... 207-231
White-pine blister rust, spread, relation of cur-
rants and gooseberries to _ 536-537
Wildlife conservation, discussion by Secretary. 94-96
Willamette Valley, Oreg., survey summary of
hop improvement, 1934-35 1233
Williams, R. D., red-clover breeder... 1198
Wisconsin, University of, duck breeding 1377
Wood, M. N.: Nut Breeding. With H. L.
Crane and C. A. Keed 827-889
Yearbook articles, summary 122-170
Yerkes, Guy E.: Some Unusual Opportu-
nities in Plant Breeding. With George M.
Darrow _ 545-558
Young, B. M., pioneer breeder of blackberries. 503
o
138904°— 37-
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